diff --git a/en_US.ISO8859-1/books/arch-handbook/Makefile b/en_US.ISO8859-1/books/arch-handbook/Makefile index 0d446a0995..f0390ebe65 100644 --- a/en_US.ISO8859-1/books/arch-handbook/Makefile +++ b/en_US.ISO8859-1/books/arch-handbook/Makefile @@ -1,54 +1,55 @@ # # $FreeBSD$ # # Build the FreeBSD Developers' Handbook. # MAINTAINER=murray@FreeBSD.org DOC?= book FORMATS?= html-split HAS_INDEX= true INSTALL_COMPRESSED?= gz INSTALL_ONLY_COMPRESSED?= # Images IMAGES= sockets/layers.eps sockets/sain.eps sockets/sainfill.eps sockets/sainlsb.eps sockets/sainmsb.eps sockets/sainserv.eps sockets/serv.eps sockets/serv2.eps sockets/slayers.eps # # SRCS lists the individual SGML files that make up the document. Changes # to any of these files will force a rebuild # # SGML content SRCS= book.sgml SRCS+= boot/chapter.sgml SRCS+= dma/chapter.sgml SRCS+= driverbasics/chapter.sgml SRCS+= introduction/chapter.sgml SRCS+= ipv6/chapter.sgml SRCS+= isa/chapter.sgml SRCS+= jail/chapter.sgml SRCS+= kerneldebug/chapter.sgml SRCS+= kobj/chapter.sgml SRCS+= l10n/chapter.sgml SRCS+= locking/chapter.sgml +SRCS+= mac/chapter.sgml SRCS+= pci/chapter.sgml SRCS+= policies/chapter.sgml SRCS+= scsi/chapter.sgml SRCS+= secure/chapter.sgml SRCS+= sockets/chapter.sgml SRCS+= sound/chapter.sgml SRCS+= sysinit/chapter.sgml SRCS+= tools/chapter.sgml SRCS+= usb/chapter.sgml SRCS+= vm/chapter.sgml SRCS+= x86/chapter.sgml # Entities DOC_PREFIX?= ${.CURDIR}/../../.. .include "${DOC_PREFIX}/share/mk/doc.project.mk" diff --git a/en_US.ISO8859-1/books/arch-handbook/book.sgml b/en_US.ISO8859-1/books/arch-handbook/book.sgml index 2a50cec9b8..89027183b6 100644 --- a/en_US.ISO8859-1/books/arch-handbook/book.sgml +++ b/en_US.ISO8859-1/books/arch-handbook/book.sgml @@ -1,302 +1,304 @@ %bookinfo; %man; %chapters; + %mac-entities; %authors %mailing-lists; ]> FreeBSD Developers' Handbook The FreeBSD Documentation Project August 2000 2000 2001 2002 The FreeBSD Documentation Project &bookinfo.legalnotice; Welcome to the Developers' Handbook. This manual is a work in progress and is the work of many individuals. Many sections do not yet exist and some of those that do exist need to be updated. If you are interested in helping with this project, send email to the &a.doc;. The latest version of this document is always available from the FreeBSD World Wide Web server. It may also be downloaded in a variety of formats and compression options from the FreeBSD FTP server or one of the numerous mirror sites. Basics &chap.introduction; &chap.tools; &chap.secure; &chap.l10n; &chap.policies; Interprocess Communication * Signals Signals, pipes, semaphores, message queues, shared memory, ports, sockets, doors &chap.sockets; &chap.ipv6; Kernel &chap.boot; &chap.locking; &chap.kobj; &chap.jail; &chap.sysinit; + &chap.mac; &chap.vm; &chap.dma; &chap.kerneldebug; * UFS UFS, FFS, Ext2FS, JFS, inodes, buffer cache, labeling, locking, metadata, soft-updates, LFS, portalfs, procfs, vnodes, memory sharing, memory objects, TLBs, caching * AFS AFS, NFS, SANs, etc. * Syscons Syscons, tty, PCVT, serial console, screen savers, etc. * Compatibility Layers * Linux Linux, SVR4, etc. Device Drivers &chap.driverbasics; &chap.isa; &chap.pci; &chap.scsi; &chap.usb; * NewBus This chapter will talk about the FreeBSD NewBus architecture. &chap.snd; Architectures &chap.x86; * Alpha Talk about the architectural specifics of FreeBSD/alpha. Explanation of alignment errors, how to fix, how to ignore. Example assembly language code for FreeBSD/alpha. * IA-64 Talk about the architectural specifics of FreeBSD/ia64. Appendices Dave A Patterson John L Hennessy 1998Morgan Kaufmann Publishers, Inc. 1-55860-428-6 Morgan Kaufmann Publishers, Inc. Computer Organization and Design The Hardware / Software Interface 1-2 W. Richard Stevens 1993Addison Wesley Longman, Inc. 0-201-56317-7 Addison Wesley Longman, Inc. Advanced Programming in the Unix Environment 1-2 Marshall Kirk McKusick Keith Bostic Michael J Karels John S Quarterman 1996Addison-Wesley Publishing Company, Inc. 0-201-54979-4 Addison-Wesley Publishing Company, Inc. The Design and Implementation of the 4.4 BSD Operating System 1-2 Aleph One Phrack 49; "Smashing the Stack for Fun and Profit" Chrispin Cowan Calton Pu Dave Maier StackGuard; Automatic Adaptive Detection and Prevention of Buffer-Overflow Attacks Todd Miller Theo de Raadt strlcpy and strlcat -- consistent, safe string copy and concatenation. diff --git a/en_US.ISO8859-1/books/arch-handbook/chapters.ent b/en_US.ISO8859-1/books/arch-handbook/chapters.ent index a529ab7daf..ccb6a43c74 100644 --- a/en_US.ISO8859-1/books/arch-handbook/chapters.ent +++ b/en_US.ISO8859-1/books/arch-handbook/chapters.ent @@ -1,46 +1,47 @@ + diff --git a/en_US.ISO8859-1/books/arch-handbook/mac.ent b/en_US.ISO8859-1/books/arch-handbook/mac.ent new file mode 100644 index 0000000000..381b994b23 --- /dev/null +++ b/en_US.ISO8859-1/books/arch-handbook/mac.ent @@ -0,0 +1,18 @@ + + + + + + + + + + Parameter + Description + Locking + + +'> diff --git a/en_US.ISO8859-1/books/arch-handbook/mac/chapter.sgml b/en_US.ISO8859-1/books/arch-handbook/mac/chapter.sgml new file mode 100644 index 0000000000..dae0ee52be --- /dev/null +++ b/en_US.ISO8859-1/books/arch-handbook/mac/chapter.sgml @@ -0,0 +1,5681 @@ + + + + + + + Chris + Costello + + + TrustedBSD Project +
chris@FreeBSD.org
+ + + + + Robert + Watson + + + TrustedBSD Project +
rwatson@FreeBSD.org
+ + + + + + Writing MAC Policies + + + Synopsis + + MAC, or Mandatory Access Control, is a feature introduced by + the TrustedBSD Project to supplement the existing standard DAC + (Discreationary Access Control) policies of BSD Unix systems. + + This chapter introduces the MAC policy framework and + provides documentation for a sample MAC policy module. + + + + + Introduction + + The TrustedBSD MAC framework provides a mechanism to allow + the compile-time or run-time extension of the kernel access + control model. New system policies may be implemented as + kernel modules and linked to the kernel; if multiple policy + modules are present, their results will be composed. While the + framework is intended to support a variety of access control + models, its design was derived from the requirements of a set + of specific access control models required for the TrustedBSD + and CBOSS Projects. This includes support for fixed and + floating label Biba integrity policies, the MLS + confidentiality policy, the Type Enforcement rule-based access + control policy, and the ability to support layering of the NSA + FLASK framework above the TrustedBSD MAC framework. This + document describes the rough architecture of the framework, + with the understanding that this is a work-in-progress and may + change subtantially as requirements evolve. + + + + Kernel Architecture + + The TrustedBSD MAC framework provides the opportunity for + policy modules to be augment system access control decisions. + Policies are permitted the opportunity to restrict the set of + rights available for processes at a variety of relevant points + in the kernel. In addition, they are provided the opportunity + to tag processes and various kernel objects with labels storing + access control information. Policy modules may register + interest in a subset of the total available events or objects, + and are not required to implement events or objects that are not + relevant to the policy. Multiple modules may be loaded at once, + and the results of the modules are composed as necessary to + build an over-all system policy. Policy modules may be + implemented such that they can be loaded on-demand at run-time, + or such that they may only be loaded early in the boot process. + This permits policies requiring pervasive labeling of all + objects to prevent improper use. + + + + Userland Architecture + + ... + + + + Entry Point Framework + + Four classes of entry points are offered to policies + registered with the framework: entry points associated with + the registration and management of policies, entry points + denoting initialization, creation, destruction, and other life + cycle events for kernel objects, events assocated with access + control decisions that the policy module may influence, and + calls associated with the management of labels on objects. In + addition, a mac_syscall() entry point is + provided so that policies may extend the kernel interface + without registering new system calls. + + Policy module writers should be aware of the kernel + locking strategy, as well as what object locks are available + during which entry points. Writers should attempt to avoid + deadlock scenarios by avoiding grabbing non-leaf locks inside + of entry points, and also follow the locking protocol for + object access and modification. In particular, writers should + be aware that while necessary locks to access objects and + their labels are generally held, sufficient locks to modify an + object or its label may not be present for all entry points. + Locking information for arguments is documented in the MAC + framework entry point document. + + Policy entry points will pass a reference to the object + label along with the object itself. This permits labeled + policies to be unaware of the internals of the object yet + still make decisions based on the label. The exception to this + is the process credential, which is assumed to be understood + by policies as a first class security object in the kernel. + Policies that do not implement labels on kernel objects will + be passed NULL pointers for label arguments to entry + points. + + + Policy Module Registration + + Modules may be declared using the + MAC_POLICY_SET() macro, which names the + policy, provides a reference to the MAC entry point vector, + provides load-time flags determining how the policy framework + should handle the policy, and optionally requests the + allocation of label state by the framework: + + static struct mac_policy_op_entry mac_none_ops[] = +{ + { MAC_DESTROY, + (macop_t)mac_none_destroy }, + { MAC_INIT, + (macop_t)mac_none_init }, + { MAC_INIT_BPFDESC, + (macop_t)mac_none_init_bpfdesc }, +/* ... */ + { MAC_CHECK_VNODE_STAT, + (macop_t)mac_none_check_vnode_stat }, + { MAC_CHECK_VNODE_WRITE, + (macop_t)mac_none_check_vnode_write }, + { MAC_OP_LAST, NULL } +}; + + The MAC policy entry point vector, + mac_none_ops in this example, associates + functions defined in the module with specific entry points. A + complete listing of available entry points and their + prototypes may be found in the MAC entry point reference + section. Of specific interest during module registration are + the MAC_DESTROY and MAC_INIT + entry points. MAC_INIT will be invoked once a + policy is successfully registered with the module framework + but prior to any other entry points becoming active. This + permits the policy to perform any policy-specific allocation + and initialization, such as initialization of any data or + locks. MAC_DESTROY will be invoked when a + policy module is unloaded to permit releasing of any allocated + memory and destruction of locks. Currently, these two entry + points are invoked with the MAC policy list mutex held to + prevent any other entry points from being invoked: this will + be changed, but in the mean time, policies should be careful + about what kernel primitives they invoke so as to avoid lock + ordering or sleeping problems. + + The policy declaration's module name field exists so that + the module may be uniquely identified for the purposes of + module dependencies. An appropriate string should be selected. + The full string name of the policy is displayed to the user + via the kernel log during load and unload events, and also + exported when providing status information to userland + processes. + + The policy flags field permits the module to provide the + framework with information about its loader-related + capabilities. Currently, two flags are defined: + + + + MPC_LOADTIME_FLAG_UNLOADOK + + + This flag indicates that the policy module may be + unloaded. If this flag is not provided, then the policy + framework will reject requests to unload the module. + This flag might be used by modules that allocate label + state and are unable to free that state at + runtime. + + + + + MPC_LOADTIME_FLAG_NOTLATE + + This flag indicates that the policy module + must be loaded and initialized early in the boot + process. If the flag is specified, attempts to register + the module following boot will be rejected. The flag + may be used by policies that require pervasive labeling + of all system objects, and cannot handle objects that + have not been properly initialized by the policy. + + + + + + <function>&mac.mpo;_init</function + + + + void + &mac.mpo;_init + + struct mac_policy_conf + *conf + + + + + + &mac.thead; + + + + conf + MAC policy definition + + + + + + Policy load event. The policy list mutex is held, so + caution should be applied. + + + + <function>&mac.mpo;_destroy</function> + + + + void + &mac.mpo;_destroy + + struct mac_policy_conf + *conf + + + + + + &mac.thead; + + + + conf + MAC policy definition + + + + + + Policy load event. The policy list mutex is held, so + caution should be applied. + + + + + Label Events + + This class of entry points is used by the MAC framework to + permit policies to maintain label information on kernel + objects. For each labeled kernel object of interest to a MAC + policy, entry points may be registered for relevant life cycle + events. All objects implement initialization, creation, and + destruction hooks. Some objects will also implement + relabeling, allowing user processes to change the labels on + objects. Some objects will also implement object-specific + events, such as label events associated with IP reassembly. A + typical labeled object will have the following life cycle of + entry points: + + Label initialization o +(object-specific wait) \ +Label creation o + \ +Relabel events, o--<--. +Various object-specific, | | +Access control events ~-->--o + \ +Label destruction o + + Label initialization permits policies to allocate memory + and set initial values for labels without context for the use + of the object. The label slot allocated to a policy will be + zero'd by default, so some policies may not need to perform + initialization. + + Label creation occurs when the kernel structure is + associated with an actual kernel object. For example, mbufs + may be allocated and remain unused in a pool until they are + required. mbuf allocation causes label initialization on the + mbuf to take place, but mbuf creation occurs when the mbuf is + associated with a datagram. Typically, context will be + provided for a creation event, including the circumstances of + the creation, and labels of other relevant objects in the + creation process. For example, when an mbuf is created from a + socket, the socket and its label will be presented to + registered policies in addition to the new mbuf and its label. + Memory allocation in creation events is discouraged, as it may + occur in performance sensitive ports of the kernel; in + addition, creation calls are not permitted to fail so a + failure to allocate memory cannot be reported. + + Object specific events do not generally fall into the + other broad classes of label events, but will generally + provide an opportunity to modify or update the label on an + object based on additional context. For example, the label on + an IP fragment reassembly queue may be updated during the + MAC_UPDATE_IPQ entry point as a result of the + acceptance of an additional mbuf to that queue. + + Access control events are discussed in detail in the + following section. + + Label destruction permits policies to release storage or + state associated with a label during its association with an + object so that the kernel data structures supporting the + object may be reused or released. + + In addition to labels associated with specific kernel + objects, an additional class of labels exists: temporary + labels. These labels are used to store update information + submitted by user processes. These labels are initialized and + destroyed as with other label types, but the creation event is + MAC_INTERNALIZE, which accepts a user label + to be converted to an in-kernel representation. + + + File System Object Labeling Event Operations + + + <function>&mac.mpo;_create_devfs_device</function> + + + + void + &mac.mpo;_create_devfs_device + + dev_t dev + struct devfs_dirent + *devfs_dirent + struct label + *label + + + + + + &mac.thead; + + + + dev + Device corresponding with + devfs_dirent + + + + devfs_dirent + Devfs directory entry to be labeled. + + + + label + Label for devfs_dirent + to be filled in. + + + + + + Fill out the label on a devfs_dirent being created for + the passed device. This call will be made when the device + file system is mounted, regenerated, or a new device is made + available. + + + + <function>&mac.mpo;_create_devfs_directory</function> + + + + void + &mac.mpo;_create_devfs_directory + + char *dirname + int dirnamelen + struct devfs_dirent + *devfs_dirent + struct label + *label + + + + + + &mac.thead; + + + + dirname + Name of directory being created + + + + namelen + Length of string + dirname + + + + devfs_dirent + Devfs directory entry for directory being + created. + + + + + + Fill out the label on a devfs_dirent being created for + the passed directory. This call will be made when the device + file system is mounted, regenerated, or a new device + requiring a specific directory hierarchy is made + available. + + + + <function>&mac.mpo;_create_devfs_vnode</function> + + + + void + &mac.mpo;_create_devfs_vnode + + struct devfs_dirent + *devfs_dirent + struct label + *direntlabel + struct vnode + *vp + struct label + *vnodelabel + + + + + + &mac.thead; + + + + devfs_dirent + Object; devfs directory entry + + + + direntlabel + Policy label for + devfs_dirent + + + + vp + Object; file system object being labeled + + + + vnodelabel + Policy label to be filled in for + vp + + + + + + Fill out the label on the vnode being created for the + passed devfs_dirent. This call will be made when a vnode is + required to represent the specified devfs_dirent in a + mounted devfs instance. + + + + <function>&mac.mpo;_vnode_create_from_vnode</function> + + + + void + &mac.mpo;_vnode_create_from_vnode + + struct ucred + *cred + struct vnode + *parent + struct label + *parentlabel + struct vnode + *child + struct label + *childlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + parent + Parent vnode; the directory in which + child is being + created + + + + parentlabel + Policy label for + parent + + + + child + New vnode + + + + childlabel + Label to be filled in for + child + + + + + + Fill out the label on the vnode being created in the + passed vnode parent by the passed subject credential. This + call will be made when a vnode is allocated during a vnode + creation operation. For example, this call is made by + multi-label file systems during the creation of a new file + or directory. + + + + <function>&mac.mpo;_create_mount</function> + + + + void + &mac.mpo;_create_mount + + struct ucred + *cred + struct mount + *mp + struct label + *mnt + struct label + *fslabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + mp + Object; file system being mounted + + + + mntlabel + Policy label to be filled in for + mp + + + + fslabel + Policy label for the file system + mp mounts. + + + + + + Fill out the labels on the mount point being created by + the passed subject credential. This call will be made when + a new file system is mounted. + + + + <function>&mac.mpo;_create_root_mount</function> + + + + void + &mac.mpo;_create_root_mount + + struct ucred + *cred + struct mount + *mp + struct label + *mntlabel + struct label + *fslabel + + + + + + &mac.thead; + + + + See . + + + + + + Fill out the labels on the mount point being created by + the passed subject credential. This call will be made when + the root file system is mounted, after + &mac.mpo;_create_mount;. + + + + <function>&mac.mpo;_vnode_relabel</function> + + + + void + &mac.mpo;_vnode_relabel + + struct ucred + *cred + struct vnode + *vp + struct label + *vnodelabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + vnode to relabel + + + + vnodelabel + Existing policy label for + vp + + + + newlabel + New, possibly partial label to replace + vnodelabel + + + + + + Update the label on the passed vnode given the passed + update vnode label and the passed subject credential. + + + + <function>&mac.mpo;_stdcreatevnode_ea</function> + + + + int + &mac.mpo;_stdcreatevnode_ea + + struct vnode + *vp + struct label + *vnodelabel + + + + + + &mac.thead; + + + + vp + vnode to commit + Locked on entry, locked on exit + + + + vnodelabel + Label associated with + vp + + + + + + + This entry point is called when a vnode is to be + committed to disk via the extended attribute service (see + &man.extattr.9;). If committing to the disk is successful, + a value of 0 should be returned; + otherwise, an appropriate error code should be + returned. + + The current implementation as of July 24, 2002 + commits the data to disk from within the architecture. + The implementation will be updated to be closer to the + above documentation as development progresses. + + + + <function>&mac.mpo;_update_devfsdirent</function> + + + void + &mac.mpo;_update_devfsdirent + + struct devfs_dirent + *devfs_dirent + struct label + *direntlabel + struct vnode + *vp + struct label + *vnodelabel + + + + + + &mac.thead; + + + + devfs_dirent + Object; devfs directory entry + + + + direntlabel + Policy label for + devfs_dirent to be + updated. + + + + vp + Parent vnode + Locked + + + + vnodelabel + Policy label for + vp + + + + + + Update the devfs_dirent label + from the passed devfs vnode label. This call will be made + when a devfs vnode has been successfully relabeled to commit + the label change such that it lasts even if the vnode is + recycled. It will also be made when when a symlink is + created in devfs, following a call to + mac_vnode_create_from_vnode to + initialize the vnode label. + + + + <function>&mac.mpo;_update_procfsvnode</function> + + + + void + &mac.mpo;_update_procfsvnode + + struct vnode + *vp + struct label + *vnodelabel + struct ucred + *cred + + + + + + &mac.thead; + + + + vp + Object; procfs vnode + Locked + + + + vnodelabel + Policy label to be filled in for + vp + + + + cred + Subject; credential for the process + entry + Immutable + + + + + + Update the procfs vnode label from the passed subject + credential. This call will be made when an operation on a + procfs vnode requires a fresh label on a process-derived + vnode. + + + + <function>&mac.mpo;_update_vnode_from_extattr</function> + + + + int + &mac.mpo;_update_vnode_from_extattr + + struct vnode + *vp + struct label + *vnodelabel + struct mount + *mp + struct label + *fslabel + + + + + + &mac.thead; + + + + vp + Object; vnode whose label is being updated + Locked + + + + vnodelabel + Policy label to refresh + + + + mp + Mount point for + vp + + + + fslabel + Policy label for vp's + file system. + + + + + + Update the vnode label by refreshing the label data from + the extended attribute service for the vnode. The mount + point fslabel is also made available + so that the fslabel may be used as a + labeling source if fallback is appropriate for the policy. + This call is permitted to fail; if the call fails, the + associated label refresh will also fail, causing the failure + of the operation requiring the MAC check and vnode label + refresh, permitting a fail closed policy if + labeling data is not available. + + + + <function>&mac.mpo;_update_from_externalized</function> + + + + int + &mac.mpo;_update_from_externalized + + struct vnode + *vp + struct label + *vnodelabel + struct mac + *extmac + + + + + + &mac.thead; + + + + vp + Object; vnode + Locked + + + + vnodelabel + Policy label for + vp + + + + extmac + Externalized MAC policy label + + + + + + Update the vnode label from the passed externalized + label loaded from disk by the MAC framework. This call is + permitted to fail; if the call fails, the associated label + refresh will also fail, causing the failure of the operation + requiring the MAC check and vnode label refresh, permitting + a fail closed policy if labeling data is not + available. This call will be obsoleted by the new extended + attribute labeling interface. + + + + <function>&mac.mpo;_update_vnode_from_mount</function> + + + + void + &mac.mpo;_update_vnode_from_mount + + struct vnode + *vp + struct label + *vnodelabel + struct mount + *mp + struct label + *mountlabel + + + + + + &mac.thead; + + + + vp + Object; vnode + Locked + + + + vnodelabel + Policy label for + vp + + + + mp + Mount point where vp + resides + + + + fslabel + Policy label for the file system where + vp resides. + + + + + + Update the vnode label from the passed mount point + label. This call is made when a single label file system + vnode requires a label, or if the obsoleted MAC framework + externalized extended attribute read fails. + + + + + IPC Object Labeling Event Operations + + + <function>&mac.mpo;_create_mbuf_from_socket</function> + + + + void + &mac.mpo;_create_mbuf_from_socket + + struct socket + *so + struct label + *socketlabel + struct mbuf *m + struct label + *mbuflabel + + + + + + &mac.thead; + + + + socket + Socket + Socket locking WIP + + + + socketlabel + Policy label for + socket + + + + m + Object; mbuf + + + + mbuflabel + Policy label to fill in for + m + + + + + + Set the label on a newly created mbuf header from the + passed socket label. This call is made when a new datagram + or messsage is generated by the socket and stored in the + passed mbuf. + + + + <function>&mac.mpo;_create_socket</function> + + + + void + &mac.mpo;_create_socket + + struct ucred + *cred + struct socket + *so + struct label + *socketlabel + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + so + Object; socket to label + + + + socketlabel + Label to fill in for + so + + + + + + Set the label on a newly created socket from the passed + subject credential. This call is made when a socket is + created. + + + + <function>&mac.mpo;_create_socket_from_socket</function> + + + + void + &mac.mpo;_create_socket_from_socket + + struct socket + *oldsocket + struct label + *oldsocketlabel + struct socket + *newsocket + struct label + *newsocketlabel + + + + + + &mac.thead; + + + + oldsocket + Object; parent socket; created from + &man.listen.2; + + + + oldsocketlabel + Label for + oldsocket + + + + newsocket + Object; child socket; incoming connection + + + + newsocketlabel + Label to be filled in for + newsocket + + + + + + Set the label on a newly created stream socket from the + passed listen socket. This call may occur during &man.accept.2;, + or prior to &man.accept.2;, depending on the protocol. + + + + <function>&mac.mpo;_socket_relabel</function> + + + + void + &mac.mpo;_socket_relabel + + struct ucred + *cred + struct socket + *so + struct label + *oldlabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + so + Object; socket + + + + oldlabel + Current label for + so + + + + newlabel + Label update for + so + + + + + + Update the label on a socket from the passed socket + label update. + + + + <function>&mac.mpo;_set_socket_peer_from_mbuf</function> + + + + void + &mac.mpo;_set_socket_peer_from_mbuf + + struct mbuf + *mbuf + struct label + *mbuflabel + struct label + *oldlabel + struct label + *newlabel + + + + + + &mac.thead; + + + + mbuf + First datagram received over socket + + + + mbuflabel + Label for mbuf + + + + oldlabel + Current label for the socket + + + + newlabel + Policy label to be filled out for the + socket + + + + + + Set the peer label on a stream socket from the passed + mbuf label. This call will be made when the first datagram + is received by the stream socket, with the exception of Unix + domain sockets. + + + + <function>&mac.mpo;_set_socket_peer_from_socket</function> + + + + void + &mac.mpo;_set_socket_peer_from_socket + + struct socket + *oldsocket + struct label + *oldsocketlabel + struct socket + *newsocket + struct label + *newsocketpeerlabel + + + + + + &mac.thead; + + + + oldsocket + Local socket + + + + oldsocketlabel + Policy label for + oldsocket + + + + newsocket + Peer socket + + + + newsocketpeerlabel + Policy label to fill in for + newsocket + + + + + + + Set the peer label on a stream UNIX domain socket from + the passed remote socket endpoint. This call will be made + when the socket pair is connected, and will be made for both + endpoints. + + + + + Network Object Labeling Event Operations + + + <function>&mac.mpo;_create_bpfdesc</function> + + + + void + &mac.mpo;_create_bpfdesc + + struct ucred + *cred + struct bpf_d + *bpf_d + struct label + *bpflabel + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + bpf_d + Object; bpf descriptor + + + + bpf + Policy label to be filled in for + bpf_d + + + + + + Set the label on a newly created BPF descriptor from the + passed subject credential. This call will be made when a + BPF device node is opened by a process with the passed + subject credential. + + + + <function>&mac.mpo;_create_ifnet</function> + + + + void + &mac.mpo;_create_ifnet + + struct ifnet + *ifnet + struct label + *ifnetlabel + + + + + + &mac.thead; + + + + ifnet + Network interface + + + + ifnetlabel + Policy label to fill in for + ifnet + + + + + + Set the label on a newly created interface. This call + may be made when a new physical interface becomes available + to the system, or when a pseudo-interface is instantiated + during the boot or as a result of a user action. + + + + <function>&mac.mpo;_create_ipq</function> + + + + void + &mac.mpo;_create_ipq + + struct mbuf + *fragment + struct label + *fragmentlabel + struct ipq + *ipq + struct label + *ipqlabel + + + + + + &mac.thead; + + + + fragment + First received IP fragment + + + + fragmentlabel + Policy label for + fragment + + + + ipq + IP reassembly queue to be labeled + + + + ipqlabel + Policy label to be filled in for + ipq + + + + + + Set the label on a newly created IP fragment reassembly + queue from the mbuf header of the first received + fragment. + + + + <function>&mac.mpo;_create_datagram_from_ipq</function> + + + + void + &mac.mpo;_create_create_datagram_from_ipq + + struct ipq + *ipq + struct label + *ipqlabel + struct mbuf + *datagram + struct label + *datagramlabel + + + + + + &mac.thead; + + + + ipq + IP reassembly queue + + + + ipqlabel + Policy label for + ipq + + + + datagram + Datagram to be labeled + + + + datagramlabel + Policy label to be filled in for + datagramlabel + + + + + + Set the label on a newly reassembled IP datagram from + the IP fragment reassembly queue from which it was + generated. + + + + <function>&mac.mpo;_create_fragment</function> + + + + void + &mac.mpo;_create_fragment + + struct mbuf + *datagram + struct label + *datagramlabel + struct mbuf + *fragment + struct label + *fragmentlabel + + + + + + &mac.thead; + + + + datagram + Datagram + + + + datagramlabel + Policy label for + datagram + + + + fragment + Fragment to be labeled + + + + fragmentlabel + Policy label to be filled in for + datagram + + + + + + Set the label on the mbuf header of a newly created IP + fragment from the label on the mbuf header of the datagram + it was generate from. + + + + <function>&mac.mpo;_create_mbuf_from_mbuf</function> + + + + void + &mac.mpo;_create_mbuf_from_mbuf + + struct mbuf + *oldmbuf + struct label + *oldmbuflabel + struct mbuf + *newmbuf + struct label + *newmbuflabel + + + + + + &mac.thead; + + + + oldmbuf + Existing (source) mbuf + + + + oldmbuflabel + Policy label for + oldmbuf + + + + newmbuf + New mbuf to be labeled + + + + newmbuflabel + Policy label to be filled in for + newmbuf + + + + + + Set the label on the mbuf header of a newly created + datagram from the mbuf header of an existing datagram. This + call may be made in a number of situations, including when + an mbuf is re-allocated for alignment purposes. + + + + <function>&mac.mpo;_create_mbuf_linklayer</function> + + + + void + &mac.mpo;_create_mbuf_linklayer + + struct ifnet + *ifnet + struct label + *ifnetlabel + struct mbuf + *mbuf + struct label + *mbuflabel + + + + + + &mac.thead; + + + + ifnet + Network interface + + + + ifnetlabel + Policy label for + ifnet + + + + mbuf + mbuf header for new datagram + + + + mbuflabel + Policy label to be filled in for + mbuf + + + + + + Set the label on the mbuf header of a newly created + datagram generated for the purposes of a link layer response + for the passed interface. This call may be made in a number + of situations, including for ARP or ND6 responses in the + IPv4 and IPv6 stacks. + + + + <function>&mac.mpo;_create_mbuf_from_bpfdesc</function> + + + + void + &mac.mpo;_create_mbuf_from_bpfdesc + + struct bpf_d + *bpf_d + struct label + *bpflabel + struct mbuf + *mbuf + struct label + *mbuflabel + + + + + + &mac.thead; + + + + bpf_d + BPF descriptor + + + + bpflabel + Policy label for + bpflabel + + + + mbuf + New mbuf to be labeled + + + + mbuflabel + Policy label to fill in for + mbuf + + + + + + Set the label on the mbuf header of a newly created + datagram generated using the passed BPF descriptor. This + call is made when a write is performed to the BPF device + associated with the passed BPF descriptor. + + + + <function>&mac.mpo;_create_mbuf_from_ifnet</function> + + + + void + &mac.mpo;_create_mbuf_from_ifnet + + struct ifnet + *ifnet + struct label + *ifnetlabel + struct mbuf + *mbuf + struct label + *mbuflabel + + + + + + &mac.thead; + + + + ifnet + Network interface + + + + ifnetlabel + Policy label for + ifnetlabel + + + + mbuf + mbuf header for new datagram + + + + mbuflabel + Policy label to be filled in for + mbuf + + + + + + Set the label on the mbuf header of a newly created + datagram generated from the passed network interface. + + + + <function>&mac.mpo;_create_mbuf_multicast_encap</function> + + + + void + &mac.mpo;_create_mbuf_multicast_encap + + struct mbuf + *oldmbuf + struct label + *oldmbuflabel + struct ifnet + *ifnet + struct label + *ifnetlabel + struct mbuf + *newmbuf + struct label + *newmbuflabel + + + + + + &mac.thead; + + + + oldmbuf + mbuf header for existing datagram + + + + oldmbuflabel + Policy label for + oldmbuf + + + + ifnet + Network interface + + + + ifnetlabel + Policy label for + ifnet + + + + newmbuf + mbuf header to be labeled for new + datagram + + + + newmbuflabel + Policy label to be filled in for + newmbuf + + + + + + Set the label on the mbuf header of a newly created + datagram generated from the existing passed datagram when it + is processed by the passed multicast encapsulation + interface. This call is made when an mbuf is to be + delivered using the virtual interface. + + + + <function>&mac.mpo;_create_mbuf_netlayer</function> + + + + void + &mac.mpo;_create_mbuf_netlayer + + struct mbuf + *oldmbuf + struct label + *oldmbuflabel + struct mbuf + *newmbuf + struct label + *newmbuflabel + + + + + + &mac.thead; + + + + oldmbuf + Received datagram + + + + oldmbuflabel + Policy label for + oldmbuf + + + + newmbuf + Newly created datagram + + + + newmbuflabel + Policy label for + newmbuf + + + + + + Set the label on the mbuf header of a newly created + datagram generated by the IP stack in response to an + existing received datagram (oldmbuf). + This call may be made in a number of situations, including + when responding to ICMP request datagrams. + + + + <function>&mac.mpo;_fragment_match</function> + + + + int + &mac.mpo;_fragment_match + + struct mbuf + *fragment + struct label + *fragmentlabel + struct ipq + *ipq + struct label + *ipqlabel + + + + + + &mac.thead; + + + + fragment + IP datagram fragment + + + + fragmentlabel + Policy label for + fragment + + + + ipq + IP fragment reassembly queue + + + + ipqlabel + Policy label for + ipq + + + + + + Determine whether an mbuf header containing an IP + datagram (fragment) fragment matches + the label of the passed IP fragment reassembly queue + (ipq). Return + (1) for a successful match, or + (0) for no match. This call is + made when the IP stack attempts to find an existing fragment + reassembly queue for a newly received fragment; if this + fails, a new fragment reassembly queue may be instantiated + for the fragment. Policies may use this entry point to + prevent the reassembly of otherwise matching IP fragments if + policy does not permit them to be reassembled based on the + label or other information. + + + + <function>&mac.mpo;_ifnet_relabel</function> + + + + void + &mac.mpo;_ifnet_relabel + + struct ucred + *cred + struct ifnet + *ifnet + struct label + *ifnetlabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + ifnet + Object; Network interface + + + + ifnetlabel + Policy label for + ifnet + + + + newlabel + Label update to apply to + ifnet + + + + + + Update the label of network interface, + ifnet, based on the passed update + label, newlabel, and the passed + subject credential, cred. + + + + <function>&mac.mpo;_update_ipq</function> + + + + void + &mac.mpo;_update_ipq + + struct mbuf + *fragment + struct label + *fragmentlabel + struct ipq + *ipq + struct label + *ipqlabel + + + + + + &mac.thead; + + + + mbuf + IP fragment + + + + mbuflabel + Policy label for + mbuf + + + + ipq + IP fragment reassembly queue + + + + ipqlabel + Policy label to be updated for + ipq + + + + + + Update the label on an IP fragment reassembly queue + (ipq) based on the acceptance of the + passed IP fragment mbuf header + (mbuf). + + + + + Process Labeling Event Operations + + + <function>&mac.mpo;_create_cred</function> + + + + void + &mac.mpo;_create_cred + + struct ucred + *parent_cred + struct ucred + *child_cred + + + + + + &mac.thead; + + + + parent_cred + Parent subject credential + + + + child_cred + Child subject credential + + + + + + + Set the label of a newly created subject credential from + the passed subject credential. This call will be made when + crcopy(9) is invoked on a newly created struct + ucred. This call should not be confused with a + process forking or creation event. + + + + <function>&mac.mpo;_execve_transition</function> + + + + void + &mac.mpo;_execve_transition + + struct ucred + *old + struct ucred + *new + struct vnode + *vp + struct label + *vnodelabel + + + + + + &mac.thead; + + + + old + Existing subject credential + Immutable + + + + new + New subject credential to be labeled + + + + vp + File to execute + Locked + + + + vnodelabel + Policy label for + vp + + + + + + Update the label of a newly created subject credential + (new) from the passed existing + subject credential (old) based on a + label transition caused by executing the passed vnode + (vp). This call occurs when a + process executes the passed vnode and one of the policies + returns a success from the + mpo_execve_will_transition entry point. + Policies may choose to implement this call simply by + invoking mpo_create_cred and passing + the two subject credentials so as not to implement a + transitioning event. Policies should not leave this entry + point unimplemented if they implement + mpo_create_cred, even if they do not + implement + mpo_execve_will_transition. + + + + <function>&mac.mpo;_execve_will_transition</function> + + + + int + &mac.mpo;_execve_will_transition + + struct ucred + *old + struct vnode + *vp + struct label + *vnodelabel + + + + + + &mac.thead; + + + + old + Subject credential prior to + &man.execve.2; + Immutable + + + + vp + File to execute + + + + vnodelabel + Policy label for + vp + + + + + + Determine whether the policy will want to perform a + transition event as a result of the execution of the passed + vnode by the passed subject credential. Return + 1 if a transition is required, + 0 if not. Even if a policy + returns 0, it should behave + correctly in the presence of an unexpected invocation of + mpo_execve_transition, as that call may + happen as a result of another policy requesting a + transition. + + + + <function>&mac.mpo;_create_proc0</function> + + + + void + &mac.mpo;_create_proc0 + + struct ucred + *cred + + + + + + &mac.thead; + + + + cred + Subject credential to be filled in + + + + + + Create the subject credential of process 0, the parent + of all kernel processes. + + + + <function>&mac.mpo;_create_proc1</function> + + + + void + &mac.mpo;_create_proc1 + + struct ucred + *cred + + + + + + &mac.thead; + + + + cred + Subject credential to be filled in + + + + + + Create the subject credential of process 1, the parent + of all kernel processes. + + + + <function>&mac.mpo;_cred_relabel</function> + + + + void + &mac.mpo;_cred_relabel + + struct ucred + *cred + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + newlabel + Label update to apply to + cred + + + + + + Update the label on a subject credential from the passed + update label. + + + + + + Access Control Checks + + Access control entry points permit policy modules to + influence access control decisions made by the kernel. + Generally, although not always, arguments to an access control + entry point will include one or more authorizing credentials, + information (possibly including a label) for any other objects + involved in the operation. An access control entry point may + return 0 to permit the operation, and an &man.errno.2; error + value. The results of invoking the entry point across various + registered policy modules will be composed as follows: if all + modules permit the operation to succeed, success will be + returned. If one or modules returns a failure, a failure will + be returned. If more than one module returns a failure, the + errno value to return to the user will be selected using the + following precedence, implemented by the + error_select() function in + kern_mac.c: + + + + + + Most precedence + EDEADLK + + + + EINVAL + + + + ESRCH + + + + EACCES + + + Least precedence + EPERM + + + + + + If none of the error values returned by all modules are + listed in the precedence chart then an arbitrarily selected + value from the set will be returned. In general, the rules + provide precedence to errors in the following order: kernel + failures, invalid arguments, object not present, access not + permitted, other. + + + <function>&mac.mpo;_check_bpfdesc_receive</function> + + + + int + &mac.mpo;_check_bpfdesc_receive + + struct bpf_d + *bpf_d + struct label + *bpflabel + struct ifnet + *ifnet + struct label + *ifnetlabel + + + + + + &mac.thead; + + + + bpf_d + Subject; BPF descriptor + + + + bpflabel + Policy label for + bpf_d + + + + ifnet + Object; network interface + + + + ifnetlabel + Policy label for + ifnet + + + + + + Determine whether the MAC framework should permit + datagrams from the passed interface to be delivered to the + buffers of the passed BPF descriptor. Return + (0) for success, or an + errno value for failure Suggested + failure: EACCES for label mismatches, + EPERM for lack of privilege. + + + + <function>&mac.mpo;_check_socket_bind</function> + + + + int + &mac.mpo;_check_socket_bind + + struct ucred + *cred + struct socket + *socket + struct label + *socketlabel + struct sockaddr + *sockaddr + + + + + + &mac.thead; + + + + cred + Subject credential + + + + socket + Socket to be bound + + + + socketlabel + Policy label for + socket + + + + sockaddr + Address of + socket + + + + + + + + + + <function>&mac.mpo;_check_socket_connect</function> + + + + int + &mac.mpo;_check_socket_connect + + struct ucred + *cred + struct socket + *socket + struct label + *socketlabel + struct sockaddr + *sockaddr + + + + + + &mac.thead; + + + + cred + Subject credential + + + + socket + Socket to be connected + + + + socketlabel + Policy label for + socket + + + + sockaddr + Address of + socket + + + + + + Determine whether the subject credential + (cred) can connect the passed socket + (socket) to the passed socket address + (sockaddr). Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatches, + EPERM for lack of privilege. + + + + <function>&mac.mpo;_check_cred_visible</function> + + + + int + &mac.mpo;_check_cred_visible + + struct ucred + *u1 + struct ucred + *u2 + + + + + + &mac.thead; + + + + u1 + Subject credential + + + + u2 + Object credential + + + + + + Determine whether the subject credential + u1 can see other + subjects with the passed subject credential + u2. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatches, + EPERM for lack of privilege, or + ESRCH to hide visibility. This call + may be made in a number of situations, including + inter-process status sysctls used by ps, + and in procfs lookups. + + + + <function>&mac.mpo;_check_socket_visible</function> + + + + int + &mac.mpo;_check_socket_visible + + struct ucred + *cred + struct socket + *socket + struct label + *socketlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + socket + Object; socket + + + + socketlabel + Policy label for + socket + + + + + + + + + <function>&mac.mpo;_check_ifnet_relabel</function> + + + + int + &mac.mpo;_check_ifnet_relabel + + struct ucred + *cred + struct ifnet + *ifnet + struct label + *ifnetlabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + ifnet + Object; network interface + + + + ifnetlabel + Existing policy label for + ifnet + + + + newlabel + Policy label update to later be applied to + ifnet + + + + + + Determine whether the subject credential can relabel the + passed network interface to the passed label update. + + + + <function>&mac.mpo;_check_socket_relabel</function> + + + + int + &mac.mpo;_check_socket_relabel + + struct ucred + *cred + struct socket + *socket + struct label + *socketlabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + socket + Object; socket + + + + socketlabel + Existing policy label for + socket + + + + newlabel + Label update to later be applied to + socketlabel + + + + + + Determine whether the subject credential can relabel the + passed socket to the passed label update. + + + + <function>&mac.mpo;_check_cred_relabel</function> + + + + int + &mac.mpo;_check_cred_relabel + + struct ucred + *cred + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + newlabel + Label update to later be applied to + cred + + + + + + Determine whether the subject credential can relabel + itself to the passed label update. + + + + <function>&mac.mpo;_check_vnode_relabel</function> + + + + int + &mac.mpo;_check_vnode_relabel + + struct ucred + *cred + struct vnode + *vp + struct label + *vnodelabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + vp + Object; vnode + Locked + + + + vnodelabel + Existing policy label for + vp + + + + newlabel + Policy label update to later be applied to + vp + + + + + + Determine whether the subject credential can relabel the + passed vnode to the passed label update. + + + + <function>&mac.mpo;_check_mount_stat</function> + + + + int &mac.mpo;_check_mount_stat + + struct ucred + *cred + struct mount + *mp + struct label + *mountlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + mp + Object; file system mount + + + + mountlabel + Policy label for + mp + + + + + + + Determine whether the subject credential can see the + results of a statfs performed on the file system. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatches + or EPERM for lack of privilege. This + call may be made in a number of situations, including during + invocations of &man.statfs.2; and related calls, as well as to + determine what file systems to exclude from listings of file + systems, such as when &man.getfsstat.2; is invoked. + + + + <function>&mac.mpo;_check_proc_debug</function> + + + + int + &mac.mpo;_check_proc_debug + + struct ucred + *cred + struct proc + *proc + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + proc + Object; process + + + + + + Determine whether the subject credential can debug the + passed process. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, EPERM for lack of + privilege, or ESRCH to hide + visibility of the target. This call may be made in a number + of situations, including use of the &man.ptrace.2; and + &man.ktrace.2; APIs, as well as for some types of procfs + operations. + + + + <function>&mac.mpo;_check_vnode_access</function> + + + + int + &mac.mpo;_check_vnode_access + + struct ucred + *cred + struct vnode + *vp + struct label + *label + int flags + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + flags + &man.access.2; flags + + + + + + Determine how invocations of &man.access.2; and related + calls by the subject credential should return when performed + on the passed vnode using the passed access flags. This + should generally be implemented using the same semantics + used in &mac.mpo;_check_vnode_open. + Return 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatches + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_chdir</function> + + + + int + &mac.mpo;_check_vnode_chdir + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Object; vnode to &man.chdir.2; into + + + + dlabel + Policy label for + dvp + + + + + + Determine whether the subject credential can change the + process working directory to the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_create</function> + + + + int + &mac.mpo;_check_vnode_create + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + struct componentname + *cnp + struct vattr + *vap + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Object; vnode + + + + dlabel + Policy label for + dvp + + + + cnp + Component name for + dvp + + + + vap + vnode attributes for vap + + + + + + Determine whether the subject credential can create a + vnode with the passed parent directory, passed name + information, and passed attribute information. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES. for label mismatch, + or EPERM for lack of privilege. + This call may be made in a number of situations, including + as a result of calls to &man.open.2; with + O_CREAT, &man.mknod.2;, &man.mkfifo.2;, and + others. + + + + <function>&mac.mpo;_check_vnode_delete</function> + + + + int + &mac.mpo;_check_vnode_delete + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + struct vnode + *vp + void *label + struct componentname + *cnp + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Parent directory vnode + + + + dlabel + Policy label for + dvp + + + + vp + Object; vnode to delete + + + + label + Policy label for + vp + + + + cnp + Component name for + vp + + + + + + Determine whether the subject credential can delete a + vnode from the passed parent directory and passed name + information. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, or EPERM for lack of + privilege. This call may be made in a number of situations, + including as a result of calls to &man.unlink.2; and + &man.rmdir.2;. Policies implementing this entry point + should also implement + mpo_check_rename_to to authorize + deletion of objects as a result of being the target of a + rename. + + + + <function>&mac.mpo;_check_vnode_deleteacl</function> + + + + int + &mac.mpo;_check_vnode_deleteacl + + struct ucred *cred + struct vnode *vp + struct label *label + acl_type_t type + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + vp + Object; vnode + Locked + + + + label + Policy label for + vp + + + + type + ACL type + + + + + + Determine whether the subject credential can delete the + ACL of passed type from the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_exec</function> + + + + int + &mac.mpo;_check_vnode_exec + + struct ucred + *cred + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode to execute + + + + label + Policy label for + vp + + + + + + Determine whether the subject credential can execute the + passed vnode. Determination of execute privilege is made + seperately from decisions about any transitioning event. + Return 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_getacl</function> + + + + int + &mac.mpo;_check_vnode_getacl + + struct ucred + *cred + struct vnode + *vp + struct label + *label + acl_type_t + type + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + type + ACL type + + + + + + Determine whether the subject credentical can retrieve + the ACL of passed type from the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_getextattr</function> + + + + int + &mac.mpo;_check_vnode_getextattr + + struct ucred + *cred + struct vnode + *vp + struct label + *label + int + attrnamespace + const char + *name + struct uio + *uio + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + attrnamespace + Extended attribute namespace + + + + name + Extended attribute name + + + + uio + I/O structure pointer; see &man.uio.9; + + + + + + Determine whether the subject credential can retrieve + the extended attribute with the passed namespace and name + from the passed vnode. Policies implementing labeling using + extended attributes may be interested in special handling of + operations on those extended attributes. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_socket_listen</function> + + + + int + &mac.mpo;_check_socket_listen + + struct ucred + *cred + struct socket + *socket + struct label + *socketlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + socket + Object; socket + + + + socketlabel + Policy label for + socket + + + + + + Determine whether the subject credential can listen on + the passed socket. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_lookup</function> + + + + int + &mac.mpo;_check_vnode_lookup + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + struct componentname + *cnp + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Object; vnode + + + + dlabel + Policy label for + dvp + + + + cnp + Component name being looked up + + + + + + Determine whether the subject credential can perform a + lookup in the passed directory vnode for the passed name. + Return 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_open</function> + + + + int + &mac.mpo;_check_vnode_open + + struct ucred + *cred + struct vnode + *vp + struct label + *label + mode_t + acc_mode + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + acc_mode + &man.open.2; access mode + + + + + + Determine whether the subject credential can perform an + open operation on the passed vnode with the passed access + mode. Return 0 for success, or + an errno value for failure. Suggested failure: + EACCES for label mismatch, or + EPERM for lack of privilege. + + + + <function>&mac.mpo;_check_vnode_readdir</function> + + + + int + &mac.mpo;_check_vnode_readdir + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Object; directory vnode + + + + dlabel + Policy label for + dvp + + + + + + Determine whether the subject credential can perform a + readdir operation on the passed + directory vnode. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_readlink</function> + + + + int + &mac.mpo;_check_vnode_readlink + + struct ucred + *cred + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + + + Determine whether the subject credential can perform a + readlink operation on the passed + symlink vnode. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, or EPERM for lack of + privilege. This call may be made in a number of situations, + including an explicit readlink call by + the user process, or as a result of an implicit + readlink during a name lookup by the + process. + + + + <function>&mac.mpo;_check_rename_from_vnode</function> + + + + int + &mac.mpo;_check_rename_from_vnode + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + struct vnode + *vp + struct label + *label + struct componentname + *cnp + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Directory vnode + + + + dlabel + Policy label for + dvp + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + + cnp + Pathname + + + + + + Determine whether the subject credential can rename the + passed vnode (vp) in the passed + directory (dvp) using the passed name + (cnp). This call will be made in + combination with a follow-up call to + mpo_check_rename_to_vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_rename_to_vnode</function> + + + + int + &mac.mpo;_check_rename_to_vnode + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + struct vnode + *vp + struct label + *label + int samedir + struct componentname + *cnp + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Directory vnode + + + + dlabel + Policy label for dvp + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + cnp + Pathname + + + + + + Determine whether the subject credential can rename to + the passed vnode (vp) and the passed + directory (dvp) with the passed name + (cnp). This call will be made in + combination with an earlier call to + mpo_check_rename_from_vnode. + Return 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_revoke</function> + + + + int + &mac.mpo;_check_vnode_revoke + + struct ucred + *cred + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + + + Determine whether the subject credential can revoke + access to the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_setacl</function> + + + + int + &mac.mpo;_check_vnode_setacl + + struct ucred + *cred + struct vnode + *vp + struct label + *label + acl_type_t + type + struct acl + *acl + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + type + ACL type + + + + acl + ACL + + + + + + Determine whether the subject credential can set the + passed ACL of passed type on the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_setextattr</function> + + + + int + &mac.mpo;_check_vnode_setextattr + + struct ucred + *cred + struct vnode + *vp + struct label + *label + int + attrnamespace + const char + *name + struct uio + *uio + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for vp + + + + attrnamespace + Extended attribute namespace + + + + name + Extended attribute name + + + + uio + I/O structure pointer; see &man.uio.9; + + + + + + Determine whether the subject credentical can set the + extended attribute of passed name and passed namespace on + the passed vnode. Policies implementing security labels + backed into extended attributes may want to provide + additional protections for those attributes. Additionally, + policies should avoid making decisions based on the data + referenced from uio, as there is a + potential race condition between this check and the actual + operation. The uio may also be + NULL if a delete operation is being + performed. Return 0 for success, + or an errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_setflags</function> + + + + int + &mac.mpo;_check_vnode_setflags + + struct ucred + *cred + struct vnode + *vp + struct label + *label + u_long flags + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + flags + File flags; see &man.chflags.2; + + + + + + Determine whether the subject credential can set the + passed flags on the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_setmode</function> + + + + int + &mac.mpo;_check_vnode_setmode + + struct ucred + *cred + struct vnode + *vp + struct label + *label + mode_t mode + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for vp + + + + mode + File mode; see &man.chmod.2; + + + + + + Determine whether the subject credential can set the + pased mode on the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_setowner</function> + + + + int + &mac.mpo;_check_vnode_setowner + + struct ucred + *cred + struct vnode + *vp + struct label + *label + uid_t uid + gid_t gid + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for vp + + + + uid + User ID + + + + gid + Group ID + + + + + + Determine whether the subject credential can set the + passed uid and passed gid as file uid and file gid on the + passed vnode. The IDs may be set to (-1) + to request no update. Return 0 + for success, or an errno value for + failure. Suggested failure: EACCES + for label mismatch, or EPERM for lack + of privilege. + + + + <function>&mac.mpo;_check_vnode_setutimes</function> + + + + int + &mac.mpo;_check_vnode_setutimes + + struct ucred + *cred + struct vnode + *vp + struct label + *label + struct timespec + atime + struct timespec + mtime + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vp + + + + label + Policy label for + vp + + + + atime + Access time; see &man.utimes.2; + + + + mtime + Modification time; see &man.utimes.2; + + + + + + Determine whether the subject credential can set the + passed access timestamps on the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_proc_sched</function> + + + + int + &mac.mpo;_check_proc_sched + + struct ucred + *ucred + struct proc + *proc + + + + + + &mac.thead; + + + + cred + Subject credential + + + + proc + Object; process + + + + + + Determine whether the subject credential can change the + scheduling parameters of the passed process. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + EPERM for lack of privilege, or + ESRCH to limit visibility. + + See &man.setpriority.2; for more information. + + + + <function>&mac.mpo;_check_proc_signal</function> + + + + int + &mac.mpo;_check_proc_signal + + struct ucred + *cred + struct proc + *proc + int signal + + + + + + &mac.thead; + + + + cred + Subject credential + + + + proc + Object; process + + + + signal + Signal; see &man.kill.2; + + + + + + Determine whether the subject credential can deliver the + passed signal to the passed process. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + EPERM for lack of privilege, or + ESRCH to limit visibility. + + + + <function>&mac.mpo;_check_vnode_stat</function> + + + + int + &mac.mpo;_check_vnode_stat + + struct ucred + *cred + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + + + Determine whether the subject credential can + stat the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + See &man.stat.2; for more information. + + + + <function>&mac.mpo;_check_ifnet_transmit</function> + + + + int + &mac.mpo;_check_ifnet_transmit + + struct ucred + *cred + struct ifnet + *ifnet + struct label + *ifnetlabel + struct mbuf + *mbuf + struct label + *mbuflabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + ifnet + Network interface + + + + ifnetlabel + Policy label for + ifnet + + + + mbuf + Object; mbuf to be sent + + + + mbuflabel + Policy label for + mbuf + + + + + + Determine whether the network interface can transmit the + passed mbuf. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_socket_receive</function> + + + + int + &mac.mpo;_check_socket_receive + + struct ucred + *cred + struct ifnet + *ifnet + struct label + *ifnetlabel + struct mbuf + *mbuf + struct label + *mbuflabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + ifnet + Network interface + + + + ifnetlabel + Policy label for + ifnet + + + + mbuf + Object; mbuf to be received + + + + mbuflabel + Policy label for + mbuf + + + + + + Determine whether the socket may receive the datagram + stored in the passed mbuf header. Return + 0 for success, or an + errno value for failure. Suggested + failures: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_socket_visible</function> + + + + int + &mac.mpo;_check_socket_visible + + struct ucred + *cred + struct socket + *so + struct label + *socketlabel + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + so + Object; socket + + + + socketlabel + Policy label for + so + + + + + + Determine whether the subject credential cred can "see" + the passed socket (socket) using + system monitoring functions, such as those employed by + &man.netstat.8; and &man.sockstat.1;. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatches, + EPERM for lack of privilege, or + ESRCH to hide visibility. + + + + + Label Management Calls + + Relabel events occur when a user process has requested + that the label on an object be modified. A two-phase update + occurs: first, an access control check will be performed to + determine if the update is both valid and permitted, and then + the update itself is performed via a seperate entry point. + Relabel entry points typically accept the object, object label + reference, and an update label submitted by the process. + Memory allocation during relabel is discouraged, as relabel + calls are not permitted to fail (failure should be reported + earlier in the relabel check). + + + <function>&mac.mpo;_init_bpfdesc</function> + + + + void + &mac.mpo;_init_bpfdesc + + struct bpf_d + *bpf_d + struct label + *label + + + + + + &mac.thead; + + + + bpf_d + Object; bpf descriptor + + + + label + New label to apply + + + + + + Initialize the label on a newly instantiated bpfdesc (BPF + descriptor) + + + + <function>&mac.mpo;_init_devfsdirent</function> + + + + void + &mac.mpo;_init_devfsdirent + + struct devfs_dirent + *devfs_dirent + struct label + *label + + + + + + &mac.thead; + + + + devfs_dirent + Object; devfs directory entry + + + + label + New label to apply + + + + + + Initialize the label on a newly instantiated devfs + entry. + + + + <function>&mac.mpo;_init_ifnet</function> + + + + void + &mac.mpo;_init_ifnet + + struct ifnet + *ifnet + struct label + *label + + + + + + &mac.thead; + + + + ifnet + Object; network interface + + + + label + New label to apply + + + + + + Initialize the label on a newly instantiated network + interface. + + + + <function>&mac.mpo;_init_ipq</function> + + + + void + &mac.mpo;_init_ipq + + struct ipq + *ipq + struct label + *label + + + + + + &mac.thead; + + + + ipq + Object; IP reassembly queue + + + + label + New label to apply + + + + + + Initialize the label on a newly instantiated IP fragment + reassembly queue. + + + + <function>&mac.mpo;_init_mbuf</function> + + + + void + &mac.mpo;_init_mbuf + + struct mbuf + *mbuf + int how + struct label + *label + + + + + + &mac.thead; + + + + mbuf + Object; mbuf + + + + how + Blocking/non-blocking &man.malloc.9; see + below + + + + label + Policy label to initialize + + + + + Initialize the label on a newly instantiated mbuf packet + header (mbuf). The + how field may be one of + M_WAITOK and M_NOWAIT, and + should be employed to avoid performing a blocking + &man.malloc.9; during this initialization call. Mbuf + allocation frequently occurs in performance sensitive + environments, and the implementation should be careful to + avoid blocking or long-lived operations. This entry point + is permitted to fail resulting in the failure to allocate + the mbuf header. + + + + <function>&mac.mpo;_init_mount</function> + + + + void + &mac.mpo;_init_mount + + struct mount + *mount + struct label + *mntlabel + struct label + *fslabel + + + + + + + &mac.thead; + + + + mount + Object; file system mount point + + + + mntlabel + Policy label to be initialized for the mount + itself + + + + fslabel + Policy label to be initialized for the file + system + + + + + + Initialize the labels on a newly instantiated mount + point. + + + + <function>&mac.mpo;_init_socket</function> + + + + void + &mac.mpo;_init_socket + + struct socket + *socket + struct label + *label + struct label + *peerlabel + + + + + + &mac.thead; + + + + socket + Object; socket + + + + label + New label to apply to the socket + + + + peerlabel + New label to apply to the socket's peer + + + + + + Initialize the labels on a newly instantiated + socket. + + + + <function>&mac.mpo;_init_cred</function> + + + + void + &mac.mpo;_init_cred + + struct ucred + *cred + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject; user credetial + + + + label + New label + + + + + + Initialize the labels on a newly instantiated subject. + + + + <function>&mac.mpo;_init_temp</function> + + + + void + &mac.mpo;_init_temp + + struct label + *label + + + + + + &mac.thead; + + + + label + Temporary label + + + + + + Initialize a newly instantiated temporary label; + temporary labels are frequently used to hold label update + requests. + + + + <function>&mac.mpo;_init_vnode</function> + + + + void + &mac.mpo;_init_vnode + + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + vp + Object; file system object + + + + label + New label to initialize + + + + + + Initialize the label on a newly instantiated vnode. + + + + <function>&mac.mpo;_destroy_bpfdesc</function> + + + + void + &mac.mpo;_destroy_bpfdesc + + struct bpf_d + *bpf_d + struct label + *label + + + + + + &mac.thead; + + + + bpf_d + Object; bpf descriptor + + + + label + Label being destroyed + + + + + + Destroy the label on a BPF descriptor. In this entry + point, a policy module should free any internal storage + associated with label so that it may + be destroyed. + + + + <function>&mac.mpo;_destroy_devfsdirent</function> + + + + void + &mac.mpo;_destroy_devfsdirent + + struct devfs_dirent + *devfs_dirent + struct label + *label + + + + + + &mac.thead; + + + + devfs_dirent + Object; devfs directory entry + + + + label + Label being destroyed + + + + + + Destroy the label on a devfs entry. In this entry + point, a policy module should free any internal storage + asociated with label so that it may + be destroyed. + + + + <function>&mac.mpo;_destroy_ifnet</function> + + + + void + &mac.mpo;_destroy_ifnet + + struct ifnet + *ifnet + struct label + *label + + + + + + &mac.thead; + + + + ifnet + Object; network interface + + + + label + Label being destroyed + + + + + + Destroy the label on a removed interface. In this entry + point, a policy module should free any internal storage + associated with label so that it may + be destroyed. + + + + <function>&mac.mpo;_destroy_ipq</function> + + + + void + &mac.mpo;_destroy_ipq + + struct ipq + *ipq + struct label + *label + + + + + + &mac.thead; + + + + ipq + Object; IP reassembly queue + + + + label + Label being destroyed + + + + + + Destroy the label on an IP fragment queue. In this + entry point, a policy module should free any internal + storage associated with label so that + it may be destroyed. + + + + <function>&mac.mpo;_destroy_mbuf</function> + + + + void + &mac.mpo;_destroy_mbuf + + struct mbuf + *mbuf + struct label + *label + + + + + + &mac.thead; + + + + mbuf + Object; mbuf + + + + label + Label being destroyed + + + + + + Destroy the label on an mbuf header. In this entry + point, a policy module should free any internal storage + associated with label so that it may + be destroyed. + + + + <function>&mac.mpo;_destroy_mount</function> + + + + void + &mac.mpo;_destroy_mount + + struct mount + *mp + struct label + *mntlabel + struct label + *fslabel + + + + + + &mac.thead; + + + + mp + Object; file system mount point + + + + mntlabel + Mount point label being destroyed + + + + fslabel + File system label being destroyed> + + + + + + Destroy the labels on a mount point. In this entry + point, a policy module should free the internal storage + associated with mntlabel and + fslabel so that they may be + destroyed. + + + + <function>&mac.mpo;_destroy_socket</function> + + + + void + &mac.mpo;_destroy_socket + + struct socket + *socket + struct label + *label + struct label + *peerlabel + + + + + + &mac.thead; + + + + socket + Object; socket + + + + label + Socket label being destroyed + + + + peerlabel + Socket peer label being destroyed + + + + + + Destroy the labels on a socket. In this entry point, a + policy module should free any internal storage associated + with label and + peerlabel so that they may be + destroyed. + + + + <function>&mac.mpo;_destroy_cred</function> + + + + void + &mac.mpo;_destroy_cred + + struct ucred + *cred + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject; user credential + + + + label + Label being destroyed + + + + + + Destroy the label on a credential. In this entry point, + a policy module should free any internal storage associated + with label so that it may be + destroyed. + + + + <function>&mac.mpo;_destroy_temp</function> + + + + void + &mac.mpo;_destroy_temp + + struct label + *label + + + + + + &mac.thead; + + + + label + Temporary label being destroyed + + + + + + Destroy a temporary label. In this entry point, a + policy module should free any internal storage associated + with the temporary label label so + that it may be destroyed. + + + + <function>&mac.mpo;_destroy_vnode</function> + + + + void + &mac.mpo;_destroy_vnode + + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + vp + Object; file system object + + + + label + Label being destroyed + + + + + + Destroy the label on a vnode. In this entry point, a + policy module should free any internal storage associated + with label so that it may be + destroyed. + + + + <function>&mac.mpo;_externalize</function> + + + + void + &mac.mpo;_externalize + + struct label + *label + struct mac + *extmac + + + + + + &mac.thead; + + + + label + Label to be externalized + + + + extmac + MAC structure to be filled in + + + + + Given an internalized subject or object label, fill out + an externalized label. This call is permitted to fail. + This call will be obsoleted by the new userland and extended + attribute interfaces for the MAC framework. + + + + <function>&mac.mpo;_internalize</function> + + + + void + &mac.mpo;_internalize + + struct label + *label + struct mac + *extmac + + + + + + &mac.thead; + + + + label + Label to be filled in + + + + extmac + MAC structure to internalize + + + + + + Given an externalized subject or object label, likely + from userland, internalize the label. The entry point + implementation should handle incorrect or corrupted labels. + This call is permitted to fail. This call will be obsoleted + by the new userland and extended attribute interfaces for + the MAC framework. + + + + + Additional Framework API Calls + + The MAC_SYSCALL entry point provides a + policy-multiplexed system call so that policies may provide + additional services to user processes without registering + specific system calls. The policy name provided during + registration is used to demux calls from userland, and the + arguments will be forwarded to this entry point. When + implementing new services, security modules should be sure to + invoke appropriate access control checks from the MAC + framework as needed. For example, if a policy implements an + augmented signal functionality, it should call the necessary + signal access control checks to invoke the MAC framework and + other registered policies. + + + + + Userland APIs + + The userland API is still under development. + + + + Sample Policy Modules + + The mac_none policy provides sample + prototypes and registration of all available policy entry + points. + + The mac_seeotheruids policy provides + a simple access control policy without the use of labeling, + relying only on information already present in the kernel + objects. + + The mac_biba policy provides a sample + information flow based labeled access control policy, + assigning labels to all kernel objects. + + + + System Integration + ... + + + + Conclusion + + The TrustedBSD MAC framework permits kernel modules to + augment the system security policy in a highly integrated + manner. They may do this based on existing object properties, + or based on label data that is maintained with the assistance of + the MAC framework. The framework is sufficiently flexible to + implement a variety of policy types, including information flow + security policies such as MLS and Biba, as well as policies + based on existing BSD credentials or file protections. Policy + authors may wish to consult this documentation as well as + existing security modules when implementing a new security + service. + + + + diff --git a/en_US.ISO8859-1/books/developers-handbook/Makefile b/en_US.ISO8859-1/books/developers-handbook/Makefile index 0d446a0995..f0390ebe65 100644 --- a/en_US.ISO8859-1/books/developers-handbook/Makefile +++ b/en_US.ISO8859-1/books/developers-handbook/Makefile @@ -1,54 +1,55 @@ # # $FreeBSD$ # # Build the FreeBSD Developers' Handbook. # MAINTAINER=murray@FreeBSD.org DOC?= book FORMATS?= html-split HAS_INDEX= true INSTALL_COMPRESSED?= gz INSTALL_ONLY_COMPRESSED?= # Images IMAGES= sockets/layers.eps sockets/sain.eps sockets/sainfill.eps sockets/sainlsb.eps sockets/sainmsb.eps sockets/sainserv.eps sockets/serv.eps sockets/serv2.eps sockets/slayers.eps # # SRCS lists the individual SGML files that make up the document. Changes # to any of these files will force a rebuild # # SGML content SRCS= book.sgml SRCS+= boot/chapter.sgml SRCS+= dma/chapter.sgml SRCS+= driverbasics/chapter.sgml SRCS+= introduction/chapter.sgml SRCS+= ipv6/chapter.sgml SRCS+= isa/chapter.sgml SRCS+= jail/chapter.sgml SRCS+= kerneldebug/chapter.sgml SRCS+= kobj/chapter.sgml SRCS+= l10n/chapter.sgml SRCS+= locking/chapter.sgml +SRCS+= mac/chapter.sgml SRCS+= pci/chapter.sgml SRCS+= policies/chapter.sgml SRCS+= scsi/chapter.sgml SRCS+= secure/chapter.sgml SRCS+= sockets/chapter.sgml SRCS+= sound/chapter.sgml SRCS+= sysinit/chapter.sgml SRCS+= tools/chapter.sgml SRCS+= usb/chapter.sgml SRCS+= vm/chapter.sgml SRCS+= x86/chapter.sgml # Entities DOC_PREFIX?= ${.CURDIR}/../../.. .include "${DOC_PREFIX}/share/mk/doc.project.mk" diff --git a/en_US.ISO8859-1/books/developers-handbook/book.sgml b/en_US.ISO8859-1/books/developers-handbook/book.sgml index 2a50cec9b8..89027183b6 100644 --- a/en_US.ISO8859-1/books/developers-handbook/book.sgml +++ b/en_US.ISO8859-1/books/developers-handbook/book.sgml @@ -1,302 +1,304 @@ %bookinfo; %man; %chapters; + %mac-entities; %authors %mailing-lists; ]> FreeBSD Developers' Handbook The FreeBSD Documentation Project August 2000 2000 2001 2002 The FreeBSD Documentation Project &bookinfo.legalnotice; Welcome to the Developers' Handbook. This manual is a work in progress and is the work of many individuals. Many sections do not yet exist and some of those that do exist need to be updated. If you are interested in helping with this project, send email to the &a.doc;. The latest version of this document is always available from the FreeBSD World Wide Web server. It may also be downloaded in a variety of formats and compression options from the FreeBSD FTP server or one of the numerous mirror sites. Basics &chap.introduction; &chap.tools; &chap.secure; &chap.l10n; &chap.policies; Interprocess Communication * Signals Signals, pipes, semaphores, message queues, shared memory, ports, sockets, doors &chap.sockets; &chap.ipv6; Kernel &chap.boot; &chap.locking; &chap.kobj; &chap.jail; &chap.sysinit; + &chap.mac; &chap.vm; &chap.dma; &chap.kerneldebug; * UFS UFS, FFS, Ext2FS, JFS, inodes, buffer cache, labeling, locking, metadata, soft-updates, LFS, portalfs, procfs, vnodes, memory sharing, memory objects, TLBs, caching * AFS AFS, NFS, SANs, etc. * Syscons Syscons, tty, PCVT, serial console, screen savers, etc. * Compatibility Layers * Linux Linux, SVR4, etc. Device Drivers &chap.driverbasics; &chap.isa; &chap.pci; &chap.scsi; &chap.usb; * NewBus This chapter will talk about the FreeBSD NewBus architecture. &chap.snd; Architectures &chap.x86; * Alpha Talk about the architectural specifics of FreeBSD/alpha. Explanation of alignment errors, how to fix, how to ignore. Example assembly language code for FreeBSD/alpha. * IA-64 Talk about the architectural specifics of FreeBSD/ia64. Appendices Dave A Patterson John L Hennessy 1998Morgan Kaufmann Publishers, Inc. 1-55860-428-6 Morgan Kaufmann Publishers, Inc. Computer Organization and Design The Hardware / Software Interface 1-2 W. Richard Stevens 1993Addison Wesley Longman, Inc. 0-201-56317-7 Addison Wesley Longman, Inc. Advanced Programming in the Unix Environment 1-2 Marshall Kirk McKusick Keith Bostic Michael J Karels John S Quarterman 1996Addison-Wesley Publishing Company, Inc. 0-201-54979-4 Addison-Wesley Publishing Company, Inc. The Design and Implementation of the 4.4 BSD Operating System 1-2 Aleph One Phrack 49; "Smashing the Stack for Fun and Profit" Chrispin Cowan Calton Pu Dave Maier StackGuard; Automatic Adaptive Detection and Prevention of Buffer-Overflow Attacks Todd Miller Theo de Raadt strlcpy and strlcat -- consistent, safe string copy and concatenation. diff --git a/en_US.ISO8859-1/books/developers-handbook/chapters.ent b/en_US.ISO8859-1/books/developers-handbook/chapters.ent index a529ab7daf..ccb6a43c74 100644 --- a/en_US.ISO8859-1/books/developers-handbook/chapters.ent +++ b/en_US.ISO8859-1/books/developers-handbook/chapters.ent @@ -1,46 +1,47 @@ + diff --git a/en_US.ISO8859-1/books/developers-handbook/mac.ent b/en_US.ISO8859-1/books/developers-handbook/mac.ent new file mode 100644 index 0000000000..381b994b23 --- /dev/null +++ b/en_US.ISO8859-1/books/developers-handbook/mac.ent @@ -0,0 +1,18 @@ + + + + + + + + + + Parameter + Description + Locking + + +'> diff --git a/en_US.ISO8859-1/books/developers-handbook/mac/chapter.sgml b/en_US.ISO8859-1/books/developers-handbook/mac/chapter.sgml new file mode 100644 index 0000000000..dae0ee52be --- /dev/null +++ b/en_US.ISO8859-1/books/developers-handbook/mac/chapter.sgml @@ -0,0 +1,5681 @@ + + + + + + + Chris + Costello + + + TrustedBSD Project +
chris@FreeBSD.org
+ + + + + Robert + Watson + + + TrustedBSD Project +
rwatson@FreeBSD.org
+ + + + + + Writing MAC Policies + + + Synopsis + + MAC, or Mandatory Access Control, is a feature introduced by + the TrustedBSD Project to supplement the existing standard DAC + (Discreationary Access Control) policies of BSD Unix systems. + + This chapter introduces the MAC policy framework and + provides documentation for a sample MAC policy module. + + + + + Introduction + + The TrustedBSD MAC framework provides a mechanism to allow + the compile-time or run-time extension of the kernel access + control model. New system policies may be implemented as + kernel modules and linked to the kernel; if multiple policy + modules are present, their results will be composed. While the + framework is intended to support a variety of access control + models, its design was derived from the requirements of a set + of specific access control models required for the TrustedBSD + and CBOSS Projects. This includes support for fixed and + floating label Biba integrity policies, the MLS + confidentiality policy, the Type Enforcement rule-based access + control policy, and the ability to support layering of the NSA + FLASK framework above the TrustedBSD MAC framework. This + document describes the rough architecture of the framework, + with the understanding that this is a work-in-progress and may + change subtantially as requirements evolve. + + + + Kernel Architecture + + The TrustedBSD MAC framework provides the opportunity for + policy modules to be augment system access control decisions. + Policies are permitted the opportunity to restrict the set of + rights available for processes at a variety of relevant points + in the kernel. In addition, they are provided the opportunity + to tag processes and various kernel objects with labels storing + access control information. Policy modules may register + interest in a subset of the total available events or objects, + and are not required to implement events or objects that are not + relevant to the policy. Multiple modules may be loaded at once, + and the results of the modules are composed as necessary to + build an over-all system policy. Policy modules may be + implemented such that they can be loaded on-demand at run-time, + or such that they may only be loaded early in the boot process. + This permits policies requiring pervasive labeling of all + objects to prevent improper use. + + + + Userland Architecture + + ... + + + + Entry Point Framework + + Four classes of entry points are offered to policies + registered with the framework: entry points associated with + the registration and management of policies, entry points + denoting initialization, creation, destruction, and other life + cycle events for kernel objects, events assocated with access + control decisions that the policy module may influence, and + calls associated with the management of labels on objects. In + addition, a mac_syscall() entry point is + provided so that policies may extend the kernel interface + without registering new system calls. + + Policy module writers should be aware of the kernel + locking strategy, as well as what object locks are available + during which entry points. Writers should attempt to avoid + deadlock scenarios by avoiding grabbing non-leaf locks inside + of entry points, and also follow the locking protocol for + object access and modification. In particular, writers should + be aware that while necessary locks to access objects and + their labels are generally held, sufficient locks to modify an + object or its label may not be present for all entry points. + Locking information for arguments is documented in the MAC + framework entry point document. + + Policy entry points will pass a reference to the object + label along with the object itself. This permits labeled + policies to be unaware of the internals of the object yet + still make decisions based on the label. The exception to this + is the process credential, which is assumed to be understood + by policies as a first class security object in the kernel. + Policies that do not implement labels on kernel objects will + be passed NULL pointers for label arguments to entry + points. + + + Policy Module Registration + + Modules may be declared using the + MAC_POLICY_SET() macro, which names the + policy, provides a reference to the MAC entry point vector, + provides load-time flags determining how the policy framework + should handle the policy, and optionally requests the + allocation of label state by the framework: + + static struct mac_policy_op_entry mac_none_ops[] = +{ + { MAC_DESTROY, + (macop_t)mac_none_destroy }, + { MAC_INIT, + (macop_t)mac_none_init }, + { MAC_INIT_BPFDESC, + (macop_t)mac_none_init_bpfdesc }, +/* ... */ + { MAC_CHECK_VNODE_STAT, + (macop_t)mac_none_check_vnode_stat }, + { MAC_CHECK_VNODE_WRITE, + (macop_t)mac_none_check_vnode_write }, + { MAC_OP_LAST, NULL } +}; + + The MAC policy entry point vector, + mac_none_ops in this example, associates + functions defined in the module with specific entry points. A + complete listing of available entry points and their + prototypes may be found in the MAC entry point reference + section. Of specific interest during module registration are + the MAC_DESTROY and MAC_INIT + entry points. MAC_INIT will be invoked once a + policy is successfully registered with the module framework + but prior to any other entry points becoming active. This + permits the policy to perform any policy-specific allocation + and initialization, such as initialization of any data or + locks. MAC_DESTROY will be invoked when a + policy module is unloaded to permit releasing of any allocated + memory and destruction of locks. Currently, these two entry + points are invoked with the MAC policy list mutex held to + prevent any other entry points from being invoked: this will + be changed, but in the mean time, policies should be careful + about what kernel primitives they invoke so as to avoid lock + ordering or sleeping problems. + + The policy declaration's module name field exists so that + the module may be uniquely identified for the purposes of + module dependencies. An appropriate string should be selected. + The full string name of the policy is displayed to the user + via the kernel log during load and unload events, and also + exported when providing status information to userland + processes. + + The policy flags field permits the module to provide the + framework with information about its loader-related + capabilities. Currently, two flags are defined: + + + + MPC_LOADTIME_FLAG_UNLOADOK + + + This flag indicates that the policy module may be + unloaded. If this flag is not provided, then the policy + framework will reject requests to unload the module. + This flag might be used by modules that allocate label + state and are unable to free that state at + runtime. + + + + + MPC_LOADTIME_FLAG_NOTLATE + + This flag indicates that the policy module + must be loaded and initialized early in the boot + process. If the flag is specified, attempts to register + the module following boot will be rejected. The flag + may be used by policies that require pervasive labeling + of all system objects, and cannot handle objects that + have not been properly initialized by the policy. + + + + + + <function>&mac.mpo;_init</function + + + + void + &mac.mpo;_init + + struct mac_policy_conf + *conf + + + + + + &mac.thead; + + + + conf + MAC policy definition + + + + + + Policy load event. The policy list mutex is held, so + caution should be applied. + + + + <function>&mac.mpo;_destroy</function> + + + + void + &mac.mpo;_destroy + + struct mac_policy_conf + *conf + + + + + + &mac.thead; + + + + conf + MAC policy definition + + + + + + Policy load event. The policy list mutex is held, so + caution should be applied. + + + + + Label Events + + This class of entry points is used by the MAC framework to + permit policies to maintain label information on kernel + objects. For each labeled kernel object of interest to a MAC + policy, entry points may be registered for relevant life cycle + events. All objects implement initialization, creation, and + destruction hooks. Some objects will also implement + relabeling, allowing user processes to change the labels on + objects. Some objects will also implement object-specific + events, such as label events associated with IP reassembly. A + typical labeled object will have the following life cycle of + entry points: + + Label initialization o +(object-specific wait) \ +Label creation o + \ +Relabel events, o--<--. +Various object-specific, | | +Access control events ~-->--o + \ +Label destruction o + + Label initialization permits policies to allocate memory + and set initial values for labels without context for the use + of the object. The label slot allocated to a policy will be + zero'd by default, so some policies may not need to perform + initialization. + + Label creation occurs when the kernel structure is + associated with an actual kernel object. For example, mbufs + may be allocated and remain unused in a pool until they are + required. mbuf allocation causes label initialization on the + mbuf to take place, but mbuf creation occurs when the mbuf is + associated with a datagram. Typically, context will be + provided for a creation event, including the circumstances of + the creation, and labels of other relevant objects in the + creation process. For example, when an mbuf is created from a + socket, the socket and its label will be presented to + registered policies in addition to the new mbuf and its label. + Memory allocation in creation events is discouraged, as it may + occur in performance sensitive ports of the kernel; in + addition, creation calls are not permitted to fail so a + failure to allocate memory cannot be reported. + + Object specific events do not generally fall into the + other broad classes of label events, but will generally + provide an opportunity to modify or update the label on an + object based on additional context. For example, the label on + an IP fragment reassembly queue may be updated during the + MAC_UPDATE_IPQ entry point as a result of the + acceptance of an additional mbuf to that queue. + + Access control events are discussed in detail in the + following section. + + Label destruction permits policies to release storage or + state associated with a label during its association with an + object so that the kernel data structures supporting the + object may be reused or released. + + In addition to labels associated with specific kernel + objects, an additional class of labels exists: temporary + labels. These labels are used to store update information + submitted by user processes. These labels are initialized and + destroyed as with other label types, but the creation event is + MAC_INTERNALIZE, which accepts a user label + to be converted to an in-kernel representation. + + + File System Object Labeling Event Operations + + + <function>&mac.mpo;_create_devfs_device</function> + + + + void + &mac.mpo;_create_devfs_device + + dev_t dev + struct devfs_dirent + *devfs_dirent + struct label + *label + + + + + + &mac.thead; + + + + dev + Device corresponding with + devfs_dirent + + + + devfs_dirent + Devfs directory entry to be labeled. + + + + label + Label for devfs_dirent + to be filled in. + + + + + + Fill out the label on a devfs_dirent being created for + the passed device. This call will be made when the device + file system is mounted, regenerated, or a new device is made + available. + + + + <function>&mac.mpo;_create_devfs_directory</function> + + + + void + &mac.mpo;_create_devfs_directory + + char *dirname + int dirnamelen + struct devfs_dirent + *devfs_dirent + struct label + *label + + + + + + &mac.thead; + + + + dirname + Name of directory being created + + + + namelen + Length of string + dirname + + + + devfs_dirent + Devfs directory entry for directory being + created. + + + + + + Fill out the label on a devfs_dirent being created for + the passed directory. This call will be made when the device + file system is mounted, regenerated, or a new device + requiring a specific directory hierarchy is made + available. + + + + <function>&mac.mpo;_create_devfs_vnode</function> + + + + void + &mac.mpo;_create_devfs_vnode + + struct devfs_dirent + *devfs_dirent + struct label + *direntlabel + struct vnode + *vp + struct label + *vnodelabel + + + + + + &mac.thead; + + + + devfs_dirent + Object; devfs directory entry + + + + direntlabel + Policy label for + devfs_dirent + + + + vp + Object; file system object being labeled + + + + vnodelabel + Policy label to be filled in for + vp + + + + + + Fill out the label on the vnode being created for the + passed devfs_dirent. This call will be made when a vnode is + required to represent the specified devfs_dirent in a + mounted devfs instance. + + + + <function>&mac.mpo;_vnode_create_from_vnode</function> + + + + void + &mac.mpo;_vnode_create_from_vnode + + struct ucred + *cred + struct vnode + *parent + struct label + *parentlabel + struct vnode + *child + struct label + *childlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + parent + Parent vnode; the directory in which + child is being + created + + + + parentlabel + Policy label for + parent + + + + child + New vnode + + + + childlabel + Label to be filled in for + child + + + + + + Fill out the label on the vnode being created in the + passed vnode parent by the passed subject credential. This + call will be made when a vnode is allocated during a vnode + creation operation. For example, this call is made by + multi-label file systems during the creation of a new file + or directory. + + + + <function>&mac.mpo;_create_mount</function> + + + + void + &mac.mpo;_create_mount + + struct ucred + *cred + struct mount + *mp + struct label + *mnt + struct label + *fslabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + mp + Object; file system being mounted + + + + mntlabel + Policy label to be filled in for + mp + + + + fslabel + Policy label for the file system + mp mounts. + + + + + + Fill out the labels on the mount point being created by + the passed subject credential. This call will be made when + a new file system is mounted. + + + + <function>&mac.mpo;_create_root_mount</function> + + + + void + &mac.mpo;_create_root_mount + + struct ucred + *cred + struct mount + *mp + struct label + *mntlabel + struct label + *fslabel + + + + + + &mac.thead; + + + + See . + + + + + + Fill out the labels on the mount point being created by + the passed subject credential. This call will be made when + the root file system is mounted, after + &mac.mpo;_create_mount;. + + + + <function>&mac.mpo;_vnode_relabel</function> + + + + void + &mac.mpo;_vnode_relabel + + struct ucred + *cred + struct vnode + *vp + struct label + *vnodelabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + vnode to relabel + + + + vnodelabel + Existing policy label for + vp + + + + newlabel + New, possibly partial label to replace + vnodelabel + + + + + + Update the label on the passed vnode given the passed + update vnode label and the passed subject credential. + + + + <function>&mac.mpo;_stdcreatevnode_ea</function> + + + + int + &mac.mpo;_stdcreatevnode_ea + + struct vnode + *vp + struct label + *vnodelabel + + + + + + &mac.thead; + + + + vp + vnode to commit + Locked on entry, locked on exit + + + + vnodelabel + Label associated with + vp + + + + + + + This entry point is called when a vnode is to be + committed to disk via the extended attribute service (see + &man.extattr.9;). If committing to the disk is successful, + a value of 0 should be returned; + otherwise, an appropriate error code should be + returned. + + The current implementation as of July 24, 2002 + commits the data to disk from within the architecture. + The implementation will be updated to be closer to the + above documentation as development progresses. + + + + <function>&mac.mpo;_update_devfsdirent</function> + + + void + &mac.mpo;_update_devfsdirent + + struct devfs_dirent + *devfs_dirent + struct label + *direntlabel + struct vnode + *vp + struct label + *vnodelabel + + + + + + &mac.thead; + + + + devfs_dirent + Object; devfs directory entry + + + + direntlabel + Policy label for + devfs_dirent to be + updated. + + + + vp + Parent vnode + Locked + + + + vnodelabel + Policy label for + vp + + + + + + Update the devfs_dirent label + from the passed devfs vnode label. This call will be made + when a devfs vnode has been successfully relabeled to commit + the label change such that it lasts even if the vnode is + recycled. It will also be made when when a symlink is + created in devfs, following a call to + mac_vnode_create_from_vnode to + initialize the vnode label. + + + + <function>&mac.mpo;_update_procfsvnode</function> + + + + void + &mac.mpo;_update_procfsvnode + + struct vnode + *vp + struct label + *vnodelabel + struct ucred + *cred + + + + + + &mac.thead; + + + + vp + Object; procfs vnode + Locked + + + + vnodelabel + Policy label to be filled in for + vp + + + + cred + Subject; credential for the process + entry + Immutable + + + + + + Update the procfs vnode label from the passed subject + credential. This call will be made when an operation on a + procfs vnode requires a fresh label on a process-derived + vnode. + + + + <function>&mac.mpo;_update_vnode_from_extattr</function> + + + + int + &mac.mpo;_update_vnode_from_extattr + + struct vnode + *vp + struct label + *vnodelabel + struct mount + *mp + struct label + *fslabel + + + + + + &mac.thead; + + + + vp + Object; vnode whose label is being updated + Locked + + + + vnodelabel + Policy label to refresh + + + + mp + Mount point for + vp + + + + fslabel + Policy label for vp's + file system. + + + + + + Update the vnode label by refreshing the label data from + the extended attribute service for the vnode. The mount + point fslabel is also made available + so that the fslabel may be used as a + labeling source if fallback is appropriate for the policy. + This call is permitted to fail; if the call fails, the + associated label refresh will also fail, causing the failure + of the operation requiring the MAC check and vnode label + refresh, permitting a fail closed policy if + labeling data is not available. + + + + <function>&mac.mpo;_update_from_externalized</function> + + + + int + &mac.mpo;_update_from_externalized + + struct vnode + *vp + struct label + *vnodelabel + struct mac + *extmac + + + + + + &mac.thead; + + + + vp + Object; vnode + Locked + + + + vnodelabel + Policy label for + vp + + + + extmac + Externalized MAC policy label + + + + + + Update the vnode label from the passed externalized + label loaded from disk by the MAC framework. This call is + permitted to fail; if the call fails, the associated label + refresh will also fail, causing the failure of the operation + requiring the MAC check and vnode label refresh, permitting + a fail closed policy if labeling data is not + available. This call will be obsoleted by the new extended + attribute labeling interface. + + + + <function>&mac.mpo;_update_vnode_from_mount</function> + + + + void + &mac.mpo;_update_vnode_from_mount + + struct vnode + *vp + struct label + *vnodelabel + struct mount + *mp + struct label + *mountlabel + + + + + + &mac.thead; + + + + vp + Object; vnode + Locked + + + + vnodelabel + Policy label for + vp + + + + mp + Mount point where vp + resides + + + + fslabel + Policy label for the file system where + vp resides. + + + + + + Update the vnode label from the passed mount point + label. This call is made when a single label file system + vnode requires a label, or if the obsoleted MAC framework + externalized extended attribute read fails. + + + + + IPC Object Labeling Event Operations + + + <function>&mac.mpo;_create_mbuf_from_socket</function> + + + + void + &mac.mpo;_create_mbuf_from_socket + + struct socket + *so + struct label + *socketlabel + struct mbuf *m + struct label + *mbuflabel + + + + + + &mac.thead; + + + + socket + Socket + Socket locking WIP + + + + socketlabel + Policy label for + socket + + + + m + Object; mbuf + + + + mbuflabel + Policy label to fill in for + m + + + + + + Set the label on a newly created mbuf header from the + passed socket label. This call is made when a new datagram + or messsage is generated by the socket and stored in the + passed mbuf. + + + + <function>&mac.mpo;_create_socket</function> + + + + void + &mac.mpo;_create_socket + + struct ucred + *cred + struct socket + *so + struct label + *socketlabel + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + so + Object; socket to label + + + + socketlabel + Label to fill in for + so + + + + + + Set the label on a newly created socket from the passed + subject credential. This call is made when a socket is + created. + + + + <function>&mac.mpo;_create_socket_from_socket</function> + + + + void + &mac.mpo;_create_socket_from_socket + + struct socket + *oldsocket + struct label + *oldsocketlabel + struct socket + *newsocket + struct label + *newsocketlabel + + + + + + &mac.thead; + + + + oldsocket + Object; parent socket; created from + &man.listen.2; + + + + oldsocketlabel + Label for + oldsocket + + + + newsocket + Object; child socket; incoming connection + + + + newsocketlabel + Label to be filled in for + newsocket + + + + + + Set the label on a newly created stream socket from the + passed listen socket. This call may occur during &man.accept.2;, + or prior to &man.accept.2;, depending on the protocol. + + + + <function>&mac.mpo;_socket_relabel</function> + + + + void + &mac.mpo;_socket_relabel + + struct ucred + *cred + struct socket + *so + struct label + *oldlabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + so + Object; socket + + + + oldlabel + Current label for + so + + + + newlabel + Label update for + so + + + + + + Update the label on a socket from the passed socket + label update. + + + + <function>&mac.mpo;_set_socket_peer_from_mbuf</function> + + + + void + &mac.mpo;_set_socket_peer_from_mbuf + + struct mbuf + *mbuf + struct label + *mbuflabel + struct label + *oldlabel + struct label + *newlabel + + + + + + &mac.thead; + + + + mbuf + First datagram received over socket + + + + mbuflabel + Label for mbuf + + + + oldlabel + Current label for the socket + + + + newlabel + Policy label to be filled out for the + socket + + + + + + Set the peer label on a stream socket from the passed + mbuf label. This call will be made when the first datagram + is received by the stream socket, with the exception of Unix + domain sockets. + + + + <function>&mac.mpo;_set_socket_peer_from_socket</function> + + + + void + &mac.mpo;_set_socket_peer_from_socket + + struct socket + *oldsocket + struct label + *oldsocketlabel + struct socket + *newsocket + struct label + *newsocketpeerlabel + + + + + + &mac.thead; + + + + oldsocket + Local socket + + + + oldsocketlabel + Policy label for + oldsocket + + + + newsocket + Peer socket + + + + newsocketpeerlabel + Policy label to fill in for + newsocket + + + + + + + Set the peer label on a stream UNIX domain socket from + the passed remote socket endpoint. This call will be made + when the socket pair is connected, and will be made for both + endpoints. + + + + + Network Object Labeling Event Operations + + + <function>&mac.mpo;_create_bpfdesc</function> + + + + void + &mac.mpo;_create_bpfdesc + + struct ucred + *cred + struct bpf_d + *bpf_d + struct label + *bpflabel + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + bpf_d + Object; bpf descriptor + + + + bpf + Policy label to be filled in for + bpf_d + + + + + + Set the label on a newly created BPF descriptor from the + passed subject credential. This call will be made when a + BPF device node is opened by a process with the passed + subject credential. + + + + <function>&mac.mpo;_create_ifnet</function> + + + + void + &mac.mpo;_create_ifnet + + struct ifnet + *ifnet + struct label + *ifnetlabel + + + + + + &mac.thead; + + + + ifnet + Network interface + + + + ifnetlabel + Policy label to fill in for + ifnet + + + + + + Set the label on a newly created interface. This call + may be made when a new physical interface becomes available + to the system, or when a pseudo-interface is instantiated + during the boot or as a result of a user action. + + + + <function>&mac.mpo;_create_ipq</function> + + + + void + &mac.mpo;_create_ipq + + struct mbuf + *fragment + struct label + *fragmentlabel + struct ipq + *ipq + struct label + *ipqlabel + + + + + + &mac.thead; + + + + fragment + First received IP fragment + + + + fragmentlabel + Policy label for + fragment + + + + ipq + IP reassembly queue to be labeled + + + + ipqlabel + Policy label to be filled in for + ipq + + + + + + Set the label on a newly created IP fragment reassembly + queue from the mbuf header of the first received + fragment. + + + + <function>&mac.mpo;_create_datagram_from_ipq</function> + + + + void + &mac.mpo;_create_create_datagram_from_ipq + + struct ipq + *ipq + struct label + *ipqlabel + struct mbuf + *datagram + struct label + *datagramlabel + + + + + + &mac.thead; + + + + ipq + IP reassembly queue + + + + ipqlabel + Policy label for + ipq + + + + datagram + Datagram to be labeled + + + + datagramlabel + Policy label to be filled in for + datagramlabel + + + + + + Set the label on a newly reassembled IP datagram from + the IP fragment reassembly queue from which it was + generated. + + + + <function>&mac.mpo;_create_fragment</function> + + + + void + &mac.mpo;_create_fragment + + struct mbuf + *datagram + struct label + *datagramlabel + struct mbuf + *fragment + struct label + *fragmentlabel + + + + + + &mac.thead; + + + + datagram + Datagram + + + + datagramlabel + Policy label for + datagram + + + + fragment + Fragment to be labeled + + + + fragmentlabel + Policy label to be filled in for + datagram + + + + + + Set the label on the mbuf header of a newly created IP + fragment from the label on the mbuf header of the datagram + it was generate from. + + + + <function>&mac.mpo;_create_mbuf_from_mbuf</function> + + + + void + &mac.mpo;_create_mbuf_from_mbuf + + struct mbuf + *oldmbuf + struct label + *oldmbuflabel + struct mbuf + *newmbuf + struct label + *newmbuflabel + + + + + + &mac.thead; + + + + oldmbuf + Existing (source) mbuf + + + + oldmbuflabel + Policy label for + oldmbuf + + + + newmbuf + New mbuf to be labeled + + + + newmbuflabel + Policy label to be filled in for + newmbuf + + + + + + Set the label on the mbuf header of a newly created + datagram from the mbuf header of an existing datagram. This + call may be made in a number of situations, including when + an mbuf is re-allocated for alignment purposes. + + + + <function>&mac.mpo;_create_mbuf_linklayer</function> + + + + void + &mac.mpo;_create_mbuf_linklayer + + struct ifnet + *ifnet + struct label + *ifnetlabel + struct mbuf + *mbuf + struct label + *mbuflabel + + + + + + &mac.thead; + + + + ifnet + Network interface + + + + ifnetlabel + Policy label for + ifnet + + + + mbuf + mbuf header for new datagram + + + + mbuflabel + Policy label to be filled in for + mbuf + + + + + + Set the label on the mbuf header of a newly created + datagram generated for the purposes of a link layer response + for the passed interface. This call may be made in a number + of situations, including for ARP or ND6 responses in the + IPv4 and IPv6 stacks. + + + + <function>&mac.mpo;_create_mbuf_from_bpfdesc</function> + + + + void + &mac.mpo;_create_mbuf_from_bpfdesc + + struct bpf_d + *bpf_d + struct label + *bpflabel + struct mbuf + *mbuf + struct label + *mbuflabel + + + + + + &mac.thead; + + + + bpf_d + BPF descriptor + + + + bpflabel + Policy label for + bpflabel + + + + mbuf + New mbuf to be labeled + + + + mbuflabel + Policy label to fill in for + mbuf + + + + + + Set the label on the mbuf header of a newly created + datagram generated using the passed BPF descriptor. This + call is made when a write is performed to the BPF device + associated with the passed BPF descriptor. + + + + <function>&mac.mpo;_create_mbuf_from_ifnet</function> + + + + void + &mac.mpo;_create_mbuf_from_ifnet + + struct ifnet + *ifnet + struct label + *ifnetlabel + struct mbuf + *mbuf + struct label + *mbuflabel + + + + + + &mac.thead; + + + + ifnet + Network interface + + + + ifnetlabel + Policy label for + ifnetlabel + + + + mbuf + mbuf header for new datagram + + + + mbuflabel + Policy label to be filled in for + mbuf + + + + + + Set the label on the mbuf header of a newly created + datagram generated from the passed network interface. + + + + <function>&mac.mpo;_create_mbuf_multicast_encap</function> + + + + void + &mac.mpo;_create_mbuf_multicast_encap + + struct mbuf + *oldmbuf + struct label + *oldmbuflabel + struct ifnet + *ifnet + struct label + *ifnetlabel + struct mbuf + *newmbuf + struct label + *newmbuflabel + + + + + + &mac.thead; + + + + oldmbuf + mbuf header for existing datagram + + + + oldmbuflabel + Policy label for + oldmbuf + + + + ifnet + Network interface + + + + ifnetlabel + Policy label for + ifnet + + + + newmbuf + mbuf header to be labeled for new + datagram + + + + newmbuflabel + Policy label to be filled in for + newmbuf + + + + + + Set the label on the mbuf header of a newly created + datagram generated from the existing passed datagram when it + is processed by the passed multicast encapsulation + interface. This call is made when an mbuf is to be + delivered using the virtual interface. + + + + <function>&mac.mpo;_create_mbuf_netlayer</function> + + + + void + &mac.mpo;_create_mbuf_netlayer + + struct mbuf + *oldmbuf + struct label + *oldmbuflabel + struct mbuf + *newmbuf + struct label + *newmbuflabel + + + + + + &mac.thead; + + + + oldmbuf + Received datagram + + + + oldmbuflabel + Policy label for + oldmbuf + + + + newmbuf + Newly created datagram + + + + newmbuflabel + Policy label for + newmbuf + + + + + + Set the label on the mbuf header of a newly created + datagram generated by the IP stack in response to an + existing received datagram (oldmbuf). + This call may be made in a number of situations, including + when responding to ICMP request datagrams. + + + + <function>&mac.mpo;_fragment_match</function> + + + + int + &mac.mpo;_fragment_match + + struct mbuf + *fragment + struct label + *fragmentlabel + struct ipq + *ipq + struct label + *ipqlabel + + + + + + &mac.thead; + + + + fragment + IP datagram fragment + + + + fragmentlabel + Policy label for + fragment + + + + ipq + IP fragment reassembly queue + + + + ipqlabel + Policy label for + ipq + + + + + + Determine whether an mbuf header containing an IP + datagram (fragment) fragment matches + the label of the passed IP fragment reassembly queue + (ipq). Return + (1) for a successful match, or + (0) for no match. This call is + made when the IP stack attempts to find an existing fragment + reassembly queue for a newly received fragment; if this + fails, a new fragment reassembly queue may be instantiated + for the fragment. Policies may use this entry point to + prevent the reassembly of otherwise matching IP fragments if + policy does not permit them to be reassembled based on the + label or other information. + + + + <function>&mac.mpo;_ifnet_relabel</function> + + + + void + &mac.mpo;_ifnet_relabel + + struct ucred + *cred + struct ifnet + *ifnet + struct label + *ifnetlabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + ifnet + Object; Network interface + + + + ifnetlabel + Policy label for + ifnet + + + + newlabel + Label update to apply to + ifnet + + + + + + Update the label of network interface, + ifnet, based on the passed update + label, newlabel, and the passed + subject credential, cred. + + + + <function>&mac.mpo;_update_ipq</function> + + + + void + &mac.mpo;_update_ipq + + struct mbuf + *fragment + struct label + *fragmentlabel + struct ipq + *ipq + struct label + *ipqlabel + + + + + + &mac.thead; + + + + mbuf + IP fragment + + + + mbuflabel + Policy label for + mbuf + + + + ipq + IP fragment reassembly queue + + + + ipqlabel + Policy label to be updated for + ipq + + + + + + Update the label on an IP fragment reassembly queue + (ipq) based on the acceptance of the + passed IP fragment mbuf header + (mbuf). + + + + + Process Labeling Event Operations + + + <function>&mac.mpo;_create_cred</function> + + + + void + &mac.mpo;_create_cred + + struct ucred + *parent_cred + struct ucred + *child_cred + + + + + + &mac.thead; + + + + parent_cred + Parent subject credential + + + + child_cred + Child subject credential + + + + + + + Set the label of a newly created subject credential from + the passed subject credential. This call will be made when + crcopy(9) is invoked on a newly created struct + ucred. This call should not be confused with a + process forking or creation event. + + + + <function>&mac.mpo;_execve_transition</function> + + + + void + &mac.mpo;_execve_transition + + struct ucred + *old + struct ucred + *new + struct vnode + *vp + struct label + *vnodelabel + + + + + + &mac.thead; + + + + old + Existing subject credential + Immutable + + + + new + New subject credential to be labeled + + + + vp + File to execute + Locked + + + + vnodelabel + Policy label for + vp + + + + + + Update the label of a newly created subject credential + (new) from the passed existing + subject credential (old) based on a + label transition caused by executing the passed vnode + (vp). This call occurs when a + process executes the passed vnode and one of the policies + returns a success from the + mpo_execve_will_transition entry point. + Policies may choose to implement this call simply by + invoking mpo_create_cred and passing + the two subject credentials so as not to implement a + transitioning event. Policies should not leave this entry + point unimplemented if they implement + mpo_create_cred, even if they do not + implement + mpo_execve_will_transition. + + + + <function>&mac.mpo;_execve_will_transition</function> + + + + int + &mac.mpo;_execve_will_transition + + struct ucred + *old + struct vnode + *vp + struct label + *vnodelabel + + + + + + &mac.thead; + + + + old + Subject credential prior to + &man.execve.2; + Immutable + + + + vp + File to execute + + + + vnodelabel + Policy label for + vp + + + + + + Determine whether the policy will want to perform a + transition event as a result of the execution of the passed + vnode by the passed subject credential. Return + 1 if a transition is required, + 0 if not. Even if a policy + returns 0, it should behave + correctly in the presence of an unexpected invocation of + mpo_execve_transition, as that call may + happen as a result of another policy requesting a + transition. + + + + <function>&mac.mpo;_create_proc0</function> + + + + void + &mac.mpo;_create_proc0 + + struct ucred + *cred + + + + + + &mac.thead; + + + + cred + Subject credential to be filled in + + + + + + Create the subject credential of process 0, the parent + of all kernel processes. + + + + <function>&mac.mpo;_create_proc1</function> + + + + void + &mac.mpo;_create_proc1 + + struct ucred + *cred + + + + + + &mac.thead; + + + + cred + Subject credential to be filled in + + + + + + Create the subject credential of process 1, the parent + of all kernel processes. + + + + <function>&mac.mpo;_cred_relabel</function> + + + + void + &mac.mpo;_cred_relabel + + struct ucred + *cred + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + newlabel + Label update to apply to + cred + + + + + + Update the label on a subject credential from the passed + update label. + + + + + + Access Control Checks + + Access control entry points permit policy modules to + influence access control decisions made by the kernel. + Generally, although not always, arguments to an access control + entry point will include one or more authorizing credentials, + information (possibly including a label) for any other objects + involved in the operation. An access control entry point may + return 0 to permit the operation, and an &man.errno.2; error + value. The results of invoking the entry point across various + registered policy modules will be composed as follows: if all + modules permit the operation to succeed, success will be + returned. If one or modules returns a failure, a failure will + be returned. If more than one module returns a failure, the + errno value to return to the user will be selected using the + following precedence, implemented by the + error_select() function in + kern_mac.c: + + + + + + Most precedence + EDEADLK + + + + EINVAL + + + + ESRCH + + + + EACCES + + + Least precedence + EPERM + + + + + + If none of the error values returned by all modules are + listed in the precedence chart then an arbitrarily selected + value from the set will be returned. In general, the rules + provide precedence to errors in the following order: kernel + failures, invalid arguments, object not present, access not + permitted, other. + + + <function>&mac.mpo;_check_bpfdesc_receive</function> + + + + int + &mac.mpo;_check_bpfdesc_receive + + struct bpf_d + *bpf_d + struct label + *bpflabel + struct ifnet + *ifnet + struct label + *ifnetlabel + + + + + + &mac.thead; + + + + bpf_d + Subject; BPF descriptor + + + + bpflabel + Policy label for + bpf_d + + + + ifnet + Object; network interface + + + + ifnetlabel + Policy label for + ifnet + + + + + + Determine whether the MAC framework should permit + datagrams from the passed interface to be delivered to the + buffers of the passed BPF descriptor. Return + (0) for success, or an + errno value for failure Suggested + failure: EACCES for label mismatches, + EPERM for lack of privilege. + + + + <function>&mac.mpo;_check_socket_bind</function> + + + + int + &mac.mpo;_check_socket_bind + + struct ucred + *cred + struct socket + *socket + struct label + *socketlabel + struct sockaddr + *sockaddr + + + + + + &mac.thead; + + + + cred + Subject credential + + + + socket + Socket to be bound + + + + socketlabel + Policy label for + socket + + + + sockaddr + Address of + socket + + + + + + + + + + <function>&mac.mpo;_check_socket_connect</function> + + + + int + &mac.mpo;_check_socket_connect + + struct ucred + *cred + struct socket + *socket + struct label + *socketlabel + struct sockaddr + *sockaddr + + + + + + &mac.thead; + + + + cred + Subject credential + + + + socket + Socket to be connected + + + + socketlabel + Policy label for + socket + + + + sockaddr + Address of + socket + + + + + + Determine whether the subject credential + (cred) can connect the passed socket + (socket) to the passed socket address + (sockaddr). Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatches, + EPERM for lack of privilege. + + + + <function>&mac.mpo;_check_cred_visible</function> + + + + int + &mac.mpo;_check_cred_visible + + struct ucred + *u1 + struct ucred + *u2 + + + + + + &mac.thead; + + + + u1 + Subject credential + + + + u2 + Object credential + + + + + + Determine whether the subject credential + u1 can see other + subjects with the passed subject credential + u2. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatches, + EPERM for lack of privilege, or + ESRCH to hide visibility. This call + may be made in a number of situations, including + inter-process status sysctls used by ps, + and in procfs lookups. + + + + <function>&mac.mpo;_check_socket_visible</function> + + + + int + &mac.mpo;_check_socket_visible + + struct ucred + *cred + struct socket + *socket + struct label + *socketlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + socket + Object; socket + + + + socketlabel + Policy label for + socket + + + + + + + + + <function>&mac.mpo;_check_ifnet_relabel</function> + + + + int + &mac.mpo;_check_ifnet_relabel + + struct ucred + *cred + struct ifnet + *ifnet + struct label + *ifnetlabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + ifnet + Object; network interface + + + + ifnetlabel + Existing policy label for + ifnet + + + + newlabel + Policy label update to later be applied to + ifnet + + + + + + Determine whether the subject credential can relabel the + passed network interface to the passed label update. + + + + <function>&mac.mpo;_check_socket_relabel</function> + + + + int + &mac.mpo;_check_socket_relabel + + struct ucred + *cred + struct socket + *socket + struct label + *socketlabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + socket + Object; socket + + + + socketlabel + Existing policy label for + socket + + + + newlabel + Label update to later be applied to + socketlabel + + + + + + Determine whether the subject credential can relabel the + passed socket to the passed label update. + + + + <function>&mac.mpo;_check_cred_relabel</function> + + + + int + &mac.mpo;_check_cred_relabel + + struct ucred + *cred + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + newlabel + Label update to later be applied to + cred + + + + + + Determine whether the subject credential can relabel + itself to the passed label update. + + + + <function>&mac.mpo;_check_vnode_relabel</function> + + + + int + &mac.mpo;_check_vnode_relabel + + struct ucred + *cred + struct vnode + *vp + struct label + *vnodelabel + struct label + *newlabel + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + vp + Object; vnode + Locked + + + + vnodelabel + Existing policy label for + vp + + + + newlabel + Policy label update to later be applied to + vp + + + + + + Determine whether the subject credential can relabel the + passed vnode to the passed label update. + + + + <function>&mac.mpo;_check_mount_stat</function> + + + + int &mac.mpo;_check_mount_stat + + struct ucred + *cred + struct mount + *mp + struct label + *mountlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + mp + Object; file system mount + + + + mountlabel + Policy label for + mp + + + + + + + Determine whether the subject credential can see the + results of a statfs performed on the file system. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatches + or EPERM for lack of privilege. This + call may be made in a number of situations, including during + invocations of &man.statfs.2; and related calls, as well as to + determine what file systems to exclude from listings of file + systems, such as when &man.getfsstat.2; is invoked. + + + + <function>&mac.mpo;_check_proc_debug</function> + + + + int + &mac.mpo;_check_proc_debug + + struct ucred + *cred + struct proc + *proc + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + proc + Object; process + + + + + + Determine whether the subject credential can debug the + passed process. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, EPERM for lack of + privilege, or ESRCH to hide + visibility of the target. This call may be made in a number + of situations, including use of the &man.ptrace.2; and + &man.ktrace.2; APIs, as well as for some types of procfs + operations. + + + + <function>&mac.mpo;_check_vnode_access</function> + + + + int + &mac.mpo;_check_vnode_access + + struct ucred + *cred + struct vnode + *vp + struct label + *label + int flags + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + flags + &man.access.2; flags + + + + + + Determine how invocations of &man.access.2; and related + calls by the subject credential should return when performed + on the passed vnode using the passed access flags. This + should generally be implemented using the same semantics + used in &mac.mpo;_check_vnode_open. + Return 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatches + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_chdir</function> + + + + int + &mac.mpo;_check_vnode_chdir + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Object; vnode to &man.chdir.2; into + + + + dlabel + Policy label for + dvp + + + + + + Determine whether the subject credential can change the + process working directory to the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_create</function> + + + + int + &mac.mpo;_check_vnode_create + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + struct componentname + *cnp + struct vattr + *vap + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Object; vnode + + + + dlabel + Policy label for + dvp + + + + cnp + Component name for + dvp + + + + vap + vnode attributes for vap + + + + + + Determine whether the subject credential can create a + vnode with the passed parent directory, passed name + information, and passed attribute information. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES. for label mismatch, + or EPERM for lack of privilege. + This call may be made in a number of situations, including + as a result of calls to &man.open.2; with + O_CREAT, &man.mknod.2;, &man.mkfifo.2;, and + others. + + + + <function>&mac.mpo;_check_vnode_delete</function> + + + + int + &mac.mpo;_check_vnode_delete + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + struct vnode + *vp + void *label + struct componentname + *cnp + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Parent directory vnode + + + + dlabel + Policy label for + dvp + + + + vp + Object; vnode to delete + + + + label + Policy label for + vp + + + + cnp + Component name for + vp + + + + + + Determine whether the subject credential can delete a + vnode from the passed parent directory and passed name + information. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, or EPERM for lack of + privilege. This call may be made in a number of situations, + including as a result of calls to &man.unlink.2; and + &man.rmdir.2;. Policies implementing this entry point + should also implement + mpo_check_rename_to to authorize + deletion of objects as a result of being the target of a + rename. + + + + <function>&mac.mpo;_check_vnode_deleteacl</function> + + + + int + &mac.mpo;_check_vnode_deleteacl + + struct ucred *cred + struct vnode *vp + struct label *label + acl_type_t type + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + vp + Object; vnode + Locked + + + + label + Policy label for + vp + + + + type + ACL type + + + + + + Determine whether the subject credential can delete the + ACL of passed type from the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_exec</function> + + + + int + &mac.mpo;_check_vnode_exec + + struct ucred + *cred + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode to execute + + + + label + Policy label for + vp + + + + + + Determine whether the subject credential can execute the + passed vnode. Determination of execute privilege is made + seperately from decisions about any transitioning event. + Return 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_getacl</function> + + + + int + &mac.mpo;_check_vnode_getacl + + struct ucred + *cred + struct vnode + *vp + struct label + *label + acl_type_t + type + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + type + ACL type + + + + + + Determine whether the subject credentical can retrieve + the ACL of passed type from the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_getextattr</function> + + + + int + &mac.mpo;_check_vnode_getextattr + + struct ucred + *cred + struct vnode + *vp + struct label + *label + int + attrnamespace + const char + *name + struct uio + *uio + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + attrnamespace + Extended attribute namespace + + + + name + Extended attribute name + + + + uio + I/O structure pointer; see &man.uio.9; + + + + + + Determine whether the subject credential can retrieve + the extended attribute with the passed namespace and name + from the passed vnode. Policies implementing labeling using + extended attributes may be interested in special handling of + operations on those extended attributes. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_socket_listen</function> + + + + int + &mac.mpo;_check_socket_listen + + struct ucred + *cred + struct socket + *socket + struct label + *socketlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + socket + Object; socket + + + + socketlabel + Policy label for + socket + + + + + + Determine whether the subject credential can listen on + the passed socket. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_lookup</function> + + + + int + &mac.mpo;_check_vnode_lookup + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + struct componentname + *cnp + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Object; vnode + + + + dlabel + Policy label for + dvp + + + + cnp + Component name being looked up + + + + + + Determine whether the subject credential can perform a + lookup in the passed directory vnode for the passed name. + Return 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_open</function> + + + + int + &mac.mpo;_check_vnode_open + + struct ucred + *cred + struct vnode + *vp + struct label + *label + mode_t + acc_mode + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + acc_mode + &man.open.2; access mode + + + + + + Determine whether the subject credential can perform an + open operation on the passed vnode with the passed access + mode. Return 0 for success, or + an errno value for failure. Suggested failure: + EACCES for label mismatch, or + EPERM for lack of privilege. + + + + <function>&mac.mpo;_check_vnode_readdir</function> + + + + int + &mac.mpo;_check_vnode_readdir + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Object; directory vnode + + + + dlabel + Policy label for + dvp + + + + + + Determine whether the subject credential can perform a + readdir operation on the passed + directory vnode. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_readlink</function> + + + + int + &mac.mpo;_check_vnode_readlink + + struct ucred + *cred + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + + + Determine whether the subject credential can perform a + readlink operation on the passed + symlink vnode. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, or EPERM for lack of + privilege. This call may be made in a number of situations, + including an explicit readlink call by + the user process, or as a result of an implicit + readlink during a name lookup by the + process. + + + + <function>&mac.mpo;_check_rename_from_vnode</function> + + + + int + &mac.mpo;_check_rename_from_vnode + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + struct vnode + *vp + struct label + *label + struct componentname + *cnp + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Directory vnode + + + + dlabel + Policy label for + dvp + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + + cnp + Pathname + + + + + + Determine whether the subject credential can rename the + passed vnode (vp) in the passed + directory (dvp) using the passed name + (cnp). This call will be made in + combination with a follow-up call to + mpo_check_rename_to_vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_rename_to_vnode</function> + + + + int + &mac.mpo;_check_rename_to_vnode + + struct ucred + *cred + struct vnode + *dvp + struct label + *dlabel + struct vnode + *vp + struct label + *label + int samedir + struct componentname + *cnp + + + + + + &mac.thead; + + + + cred + Subject credential + + + + dvp + Directory vnode + + + + dlabel + Policy label for dvp + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + cnp + Pathname + + + + + + Determine whether the subject credential can rename to + the passed vnode (vp) and the passed + directory (dvp) with the passed name + (cnp). This call will be made in + combination with an earlier call to + mpo_check_rename_from_vnode. + Return 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_revoke</function> + + + + int + &mac.mpo;_check_vnode_revoke + + struct ucred + *cred + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + + + Determine whether the subject credential can revoke + access to the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_setacl</function> + + + + int + &mac.mpo;_check_vnode_setacl + + struct ucred + *cred + struct vnode + *vp + struct label + *label + acl_type_t + type + struct acl + *acl + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + type + ACL type + + + + acl + ACL + + + + + + Determine whether the subject credential can set the + passed ACL of passed type on the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_setextattr</function> + + + + int + &mac.mpo;_check_vnode_setextattr + + struct ucred + *cred + struct vnode + *vp + struct label + *label + int + attrnamespace + const char + *name + struct uio + *uio + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for vp + + + + attrnamespace + Extended attribute namespace + + + + name + Extended attribute name + + + + uio + I/O structure pointer; see &man.uio.9; + + + + + + Determine whether the subject credentical can set the + extended attribute of passed name and passed namespace on + the passed vnode. Policies implementing security labels + backed into extended attributes may want to provide + additional protections for those attributes. Additionally, + policies should avoid making decisions based on the data + referenced from uio, as there is a + potential race condition between this check and the actual + operation. The uio may also be + NULL if a delete operation is being + performed. Return 0 for success, + or an errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_setflags</function> + + + + int + &mac.mpo;_check_vnode_setflags + + struct ucred + *cred + struct vnode + *vp + struct label + *label + u_long flags + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + flags + File flags; see &man.chflags.2; + + + + + + Determine whether the subject credential can set the + passed flags on the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_setmode</function> + + + + int + &mac.mpo;_check_vnode_setmode + + struct ucred + *cred + struct vnode + *vp + struct label + *label + mode_t mode + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for vp + + + + mode + File mode; see &man.chmod.2; + + + + + + Determine whether the subject credential can set the + pased mode on the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_vnode_setowner</function> + + + + int + &mac.mpo;_check_vnode_setowner + + struct ucred + *cred + struct vnode + *vp + struct label + *label + uid_t uid + gid_t gid + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for vp + + + + uid + User ID + + + + gid + Group ID + + + + + + Determine whether the subject credential can set the + passed uid and passed gid as file uid and file gid on the + passed vnode. The IDs may be set to (-1) + to request no update. Return 0 + for success, or an errno value for + failure. Suggested failure: EACCES + for label mismatch, or EPERM for lack + of privilege. + + + + <function>&mac.mpo;_check_vnode_setutimes</function> + + + + int + &mac.mpo;_check_vnode_setutimes + + struct ucred + *cred + struct vnode + *vp + struct label + *label + struct timespec + atime + struct timespec + mtime + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vp + + + + label + Policy label for + vp + + + + atime + Access time; see &man.utimes.2; + + + + mtime + Modification time; see &man.utimes.2; + + + + + + Determine whether the subject credential can set the + passed access timestamps on the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_proc_sched</function> + + + + int + &mac.mpo;_check_proc_sched + + struct ucred + *ucred + struct proc + *proc + + + + + + &mac.thead; + + + + cred + Subject credential + + + + proc + Object; process + + + + + + Determine whether the subject credential can change the + scheduling parameters of the passed process. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + EPERM for lack of privilege, or + ESRCH to limit visibility. + + See &man.setpriority.2; for more information. + + + + <function>&mac.mpo;_check_proc_signal</function> + + + + int + &mac.mpo;_check_proc_signal + + struct ucred + *cred + struct proc + *proc + int signal + + + + + + &mac.thead; + + + + cred + Subject credential + + + + proc + Object; process + + + + signal + Signal; see &man.kill.2; + + + + + + Determine whether the subject credential can deliver the + passed signal to the passed process. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + EPERM for lack of privilege, or + ESRCH to limit visibility. + + + + <function>&mac.mpo;_check_vnode_stat</function> + + + + int + &mac.mpo;_check_vnode_stat + + struct ucred + *cred + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject credential + + + + vp + Object; vnode + + + + label + Policy label for + vp + + + + + + Determine whether the subject credential can + stat the passed vnode. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatch, + or EPERM for lack of + privilege. + + See &man.stat.2; for more information. + + + + <function>&mac.mpo;_check_ifnet_transmit</function> + + + + int + &mac.mpo;_check_ifnet_transmit + + struct ucred + *cred + struct ifnet + *ifnet + struct label + *ifnetlabel + struct mbuf + *mbuf + struct label + *mbuflabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + ifnet + Network interface + + + + ifnetlabel + Policy label for + ifnet + + + + mbuf + Object; mbuf to be sent + + + + mbuflabel + Policy label for + mbuf + + + + + + Determine whether the network interface can transmit the + passed mbuf. Return 0 for + success, or an errno value for failure. + Suggested failure: EACCES for label + mismatch, or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_socket_receive</function> + + + + int + &mac.mpo;_check_socket_receive + + struct ucred + *cred + struct ifnet + *ifnet + struct label + *ifnetlabel + struct mbuf + *mbuf + struct label + *mbuflabel + + + + + + &mac.thead; + + + + cred + Subject credential + + + + ifnet + Network interface + + + + ifnetlabel + Policy label for + ifnet + + + + mbuf + Object; mbuf to be received + + + + mbuflabel + Policy label for + mbuf + + + + + + Determine whether the socket may receive the datagram + stored in the passed mbuf header. Return + 0 for success, or an + errno value for failure. Suggested + failures: EACCES for label mismatch, + or EPERM for lack of + privilege. + + + + <function>&mac.mpo;_check_socket_visible</function> + + + + int + &mac.mpo;_check_socket_visible + + struct ucred + *cred + struct socket + *so + struct label + *socketlabel + + + + + + &mac.thead; + + + + cred + Subject credential + Immutable + + + + so + Object; socket + + + + socketlabel + Policy label for + so + + + + + + Determine whether the subject credential cred can "see" + the passed socket (socket) using + system monitoring functions, such as those employed by + &man.netstat.8; and &man.sockstat.1;. Return + 0 for success, or an + errno value for failure. Suggested + failure: EACCES for label mismatches, + EPERM for lack of privilege, or + ESRCH to hide visibility. + + + + + Label Management Calls + + Relabel events occur when a user process has requested + that the label on an object be modified. A two-phase update + occurs: first, an access control check will be performed to + determine if the update is both valid and permitted, and then + the update itself is performed via a seperate entry point. + Relabel entry points typically accept the object, object label + reference, and an update label submitted by the process. + Memory allocation during relabel is discouraged, as relabel + calls are not permitted to fail (failure should be reported + earlier in the relabel check). + + + <function>&mac.mpo;_init_bpfdesc</function> + + + + void + &mac.mpo;_init_bpfdesc + + struct bpf_d + *bpf_d + struct label + *label + + + + + + &mac.thead; + + + + bpf_d + Object; bpf descriptor + + + + label + New label to apply + + + + + + Initialize the label on a newly instantiated bpfdesc (BPF + descriptor) + + + + <function>&mac.mpo;_init_devfsdirent</function> + + + + void + &mac.mpo;_init_devfsdirent + + struct devfs_dirent + *devfs_dirent + struct label + *label + + + + + + &mac.thead; + + + + devfs_dirent + Object; devfs directory entry + + + + label + New label to apply + + + + + + Initialize the label on a newly instantiated devfs + entry. + + + + <function>&mac.mpo;_init_ifnet</function> + + + + void + &mac.mpo;_init_ifnet + + struct ifnet + *ifnet + struct label + *label + + + + + + &mac.thead; + + + + ifnet + Object; network interface + + + + label + New label to apply + + + + + + Initialize the label on a newly instantiated network + interface. + + + + <function>&mac.mpo;_init_ipq</function> + + + + void + &mac.mpo;_init_ipq + + struct ipq + *ipq + struct label + *label + + + + + + &mac.thead; + + + + ipq + Object; IP reassembly queue + + + + label + New label to apply + + + + + + Initialize the label on a newly instantiated IP fragment + reassembly queue. + + + + <function>&mac.mpo;_init_mbuf</function> + + + + void + &mac.mpo;_init_mbuf + + struct mbuf + *mbuf + int how + struct label + *label + + + + + + &mac.thead; + + + + mbuf + Object; mbuf + + + + how + Blocking/non-blocking &man.malloc.9; see + below + + + + label + Policy label to initialize + + + + + Initialize the label on a newly instantiated mbuf packet + header (mbuf). The + how field may be one of + M_WAITOK and M_NOWAIT, and + should be employed to avoid performing a blocking + &man.malloc.9; during this initialization call. Mbuf + allocation frequently occurs in performance sensitive + environments, and the implementation should be careful to + avoid blocking or long-lived operations. This entry point + is permitted to fail resulting in the failure to allocate + the mbuf header. + + + + <function>&mac.mpo;_init_mount</function> + + + + void + &mac.mpo;_init_mount + + struct mount + *mount + struct label + *mntlabel + struct label + *fslabel + + + + + + + &mac.thead; + + + + mount + Object; file system mount point + + + + mntlabel + Policy label to be initialized for the mount + itself + + + + fslabel + Policy label to be initialized for the file + system + + + + + + Initialize the labels on a newly instantiated mount + point. + + + + <function>&mac.mpo;_init_socket</function> + + + + void + &mac.mpo;_init_socket + + struct socket + *socket + struct label + *label + struct label + *peerlabel + + + + + + &mac.thead; + + + + socket + Object; socket + + + + label + New label to apply to the socket + + + + peerlabel + New label to apply to the socket's peer + + + + + + Initialize the labels on a newly instantiated + socket. + + + + <function>&mac.mpo;_init_cred</function> + + + + void + &mac.mpo;_init_cred + + struct ucred + *cred + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject; user credetial + + + + label + New label + + + + + + Initialize the labels on a newly instantiated subject. + + + + <function>&mac.mpo;_init_temp</function> + + + + void + &mac.mpo;_init_temp + + struct label + *label + + + + + + &mac.thead; + + + + label + Temporary label + + + + + + Initialize a newly instantiated temporary label; + temporary labels are frequently used to hold label update + requests. + + + + <function>&mac.mpo;_init_vnode</function> + + + + void + &mac.mpo;_init_vnode + + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + vp + Object; file system object + + + + label + New label to initialize + + + + + + Initialize the label on a newly instantiated vnode. + + + + <function>&mac.mpo;_destroy_bpfdesc</function> + + + + void + &mac.mpo;_destroy_bpfdesc + + struct bpf_d + *bpf_d + struct label + *label + + + + + + &mac.thead; + + + + bpf_d + Object; bpf descriptor + + + + label + Label being destroyed + + + + + + Destroy the label on a BPF descriptor. In this entry + point, a policy module should free any internal storage + associated with label so that it may + be destroyed. + + + + <function>&mac.mpo;_destroy_devfsdirent</function> + + + + void + &mac.mpo;_destroy_devfsdirent + + struct devfs_dirent + *devfs_dirent + struct label + *label + + + + + + &mac.thead; + + + + devfs_dirent + Object; devfs directory entry + + + + label + Label being destroyed + + + + + + Destroy the label on a devfs entry. In this entry + point, a policy module should free any internal storage + asociated with label so that it may + be destroyed. + + + + <function>&mac.mpo;_destroy_ifnet</function> + + + + void + &mac.mpo;_destroy_ifnet + + struct ifnet + *ifnet + struct label + *label + + + + + + &mac.thead; + + + + ifnet + Object; network interface + + + + label + Label being destroyed + + + + + + Destroy the label on a removed interface. In this entry + point, a policy module should free any internal storage + associated with label so that it may + be destroyed. + + + + <function>&mac.mpo;_destroy_ipq</function> + + + + void + &mac.mpo;_destroy_ipq + + struct ipq + *ipq + struct label + *label + + + + + + &mac.thead; + + + + ipq + Object; IP reassembly queue + + + + label + Label being destroyed + + + + + + Destroy the label on an IP fragment queue. In this + entry point, a policy module should free any internal + storage associated with label so that + it may be destroyed. + + + + <function>&mac.mpo;_destroy_mbuf</function> + + + + void + &mac.mpo;_destroy_mbuf + + struct mbuf + *mbuf + struct label + *label + + + + + + &mac.thead; + + + + mbuf + Object; mbuf + + + + label + Label being destroyed + + + + + + Destroy the label on an mbuf header. In this entry + point, a policy module should free any internal storage + associated with label so that it may + be destroyed. + + + + <function>&mac.mpo;_destroy_mount</function> + + + + void + &mac.mpo;_destroy_mount + + struct mount + *mp + struct label + *mntlabel + struct label + *fslabel + + + + + + &mac.thead; + + + + mp + Object; file system mount point + + + + mntlabel + Mount point label being destroyed + + + + fslabel + File system label being destroyed> + + + + + + Destroy the labels on a mount point. In this entry + point, a policy module should free the internal storage + associated with mntlabel and + fslabel so that they may be + destroyed. + + + + <function>&mac.mpo;_destroy_socket</function> + + + + void + &mac.mpo;_destroy_socket + + struct socket + *socket + struct label + *label + struct label + *peerlabel + + + + + + &mac.thead; + + + + socket + Object; socket + + + + label + Socket label being destroyed + + + + peerlabel + Socket peer label being destroyed + + + + + + Destroy the labels on a socket. In this entry point, a + policy module should free any internal storage associated + with label and + peerlabel so that they may be + destroyed. + + + + <function>&mac.mpo;_destroy_cred</function> + + + + void + &mac.mpo;_destroy_cred + + struct ucred + *cred + struct label + *label + + + + + + &mac.thead; + + + + cred + Subject; user credential + + + + label + Label being destroyed + + + + + + Destroy the label on a credential. In this entry point, + a policy module should free any internal storage associated + with label so that it may be + destroyed. + + + + <function>&mac.mpo;_destroy_temp</function> + + + + void + &mac.mpo;_destroy_temp + + struct label + *label + + + + + + &mac.thead; + + + + label + Temporary label being destroyed + + + + + + Destroy a temporary label. In this entry point, a + policy module should free any internal storage associated + with the temporary label label so + that it may be destroyed. + + + + <function>&mac.mpo;_destroy_vnode</function> + + + + void + &mac.mpo;_destroy_vnode + + struct vnode + *vp + struct label + *label + + + + + + &mac.thead; + + + + vp + Object; file system object + + + + label + Label being destroyed + + + + + + Destroy the label on a vnode. In this entry point, a + policy module should free any internal storage associated + with label so that it may be + destroyed. + + + + <function>&mac.mpo;_externalize</function> + + + + void + &mac.mpo;_externalize + + struct label + *label + struct mac + *extmac + + + + + + &mac.thead; + + + + label + Label to be externalized + + + + extmac + MAC structure to be filled in + + + + + Given an internalized subject or object label, fill out + an externalized label. This call is permitted to fail. + This call will be obsoleted by the new userland and extended + attribute interfaces for the MAC framework. + + + + <function>&mac.mpo;_internalize</function> + + + + void + &mac.mpo;_internalize + + struct label + *label + struct mac + *extmac + + + + + + &mac.thead; + + + + label + Label to be filled in + + + + extmac + MAC structure to internalize + + + + + + Given an externalized subject or object label, likely + from userland, internalize the label. The entry point + implementation should handle incorrect or corrupted labels. + This call is permitted to fail. This call will be obsoleted + by the new userland and extended attribute interfaces for + the MAC framework. + + + + + Additional Framework API Calls + + The MAC_SYSCALL entry point provides a + policy-multiplexed system call so that policies may provide + additional services to user processes without registering + specific system calls. The policy name provided during + registration is used to demux calls from userland, and the + arguments will be forwarded to this entry point. When + implementing new services, security modules should be sure to + invoke appropriate access control checks from the MAC + framework as needed. For example, if a policy implements an + augmented signal functionality, it should call the necessary + signal access control checks to invoke the MAC framework and + other registered policies. + + + + + Userland APIs + + The userland API is still under development. + + + + Sample Policy Modules + + The mac_none policy provides sample + prototypes and registration of all available policy entry + points. + + The mac_seeotheruids policy provides + a simple access control policy without the use of labeling, + relying only on information already present in the kernel + objects. + + The mac_biba policy provides a sample + information flow based labeled access control policy, + assigning labels to all kernel objects. + + + + System Integration + ... + + + + Conclusion + + The TrustedBSD MAC framework permits kernel modules to + augment the system security policy in a highly integrated + manner. They may do this based on existing object properties, + or based on label data that is maintained with the assistance of + the MAC framework. The framework is sufficiently flexible to + implement a variety of policy types, including information flow + security policies such as MLS and Biba, as well as policies + based on existing BSD credentials or file protections. Policy + authors may wish to consult this documentation as well as + existing security modules when implementing a new security + service. + + + +