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D45567.1775489582.diff
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diff --git a/usr.bin/wall/ttymsg.h b/usr.bin/wall/ttymsg.h
--- a/usr.bin/wall/ttymsg.h
+++ b/usr.bin/wall/ttymsg.h
@@ -1,4 +1,4 @@
#define TTYMSG_IOV_MAX 32
-const char *ttymsg(struct iovec *, int, const char *, int);
+const char *ttymsg(struct iovec *, int, const char *, int, int);
diff --git a/usr.bin/wall/ttymsg.c b/usr.bin/wall/ttymsg.c
--- a/usr.bin/wall/ttymsg.c
+++ b/usr.bin/wall/ttymsg.c
@@ -30,10 +30,13 @@
*/
-
+#include <sys/procdesc.h>
#include <sys/types.h>
#include <sys/uio.h>
+
+#include <capsicum_helpers.h>
#include <dirent.h>
+#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
@@ -53,17 +56,20 @@
* ignored (exclusive-use, lack of permission, etc.).
*/
const char *
-ttymsg(struct iovec *iov, int iovcnt, const char *line, int tmout)
+ttymsg(struct iovec *iov, int iovcnt, const char *line, int tmout, int fd)
{
struct iovec localiov[TTYMSG_IOV_MAX];
ssize_t left, wret;
- int cnt, fd;
+ int cnt;
char device[MAXNAMLEN] = _PATH_DEV;
static char errbuf[1024];
char *p;
- int forked;
+ char rel_path[1024];
+ int fd2;
+ int pd;
+ cap_rights_t rights;
- forked = 0;
+ strcpy(rel_path,"./");
if (iovcnt > (int)(sizeof(localiov) / sizeof(localiov[0])))
return ("too many iov's (change code in wall/ttymsg.c)");
@@ -82,19 +88,20 @@
* open will fail on slip lines or exclusive-use lines
* if not running as root; not an error.
*/
- if ((fd = open(device, O_WRONLY|O_NONBLOCK, 0)) < 0) {
- if (errno == EBUSY || errno == EACCES)
- return (NULL);
- (void) snprintf(errbuf, sizeof(errbuf), "%s: %s", device,
- strerror(errno));
- return (errbuf);
- }
+ strcat(rel_path, p);
+ fd2 = openat(fd, rel_path, O_WRONLY|O_NONBLOCK, O_RDONLY);
+ if (fd2 < 0)
+ err(1, "openat(%s)", rel_path);
+
+ cap_rights_init(&rights, CAP_WRITE, CAP_FSTAT,CAP_FSTATAT);
+ if (caph_rights_limit(fd2, &rights) == -1)
+ err(1, "unable to limit capability rights");
for (cnt = 0, left = 0; cnt < iovcnt; ++cnt)
left += iov[cnt].iov_len;
for (;;) {
- wret = writev(fd, iov, iovcnt);
+ wret = writev(fd2, iov, iovcnt);
if (wret >= left)
break;
if (wret >= 0) {
@@ -118,22 +125,15 @@
if (errno == EWOULDBLOCK) {
int cpid;
- if (forked) {
- (void) close(fd);
- _exit(1);
- }
- cpid = fork();
+ cpid = pdfork(&pd, 0);
if (cpid < 0) {
(void) snprintf(errbuf, sizeof(errbuf),
"fork: %s", strerror(errno));
- (void) close(fd);
return (errbuf);
}
if (cpid) { /* parent */
- (void) close(fd);
return (NULL);
}
- forked++;
/* wait at most tmout seconds */
(void) signal(SIGALRM, SIG_DFL);
(void) signal(SIGTERM, SIG_DFL); /* XXX */
@@ -148,16 +148,10 @@
*/
if (errno == ENODEV || errno == EIO)
break;
- (void) close(fd);
- if (forked)
- _exit(1);
(void) snprintf(errbuf, sizeof(errbuf),
"%s: %s", device, strerror(errno));
return (errbuf);
}
- (void) close(fd);
- if (forked)
- _exit(0);
return (NULL);
}
diff --git a/usr.bin/wall/wall.c b/usr.bin/wall/wall.c
--- a/usr.bin/wall/wall.c
+++ b/usr.bin/wall/wall.c
@@ -36,9 +36,12 @@
#include <sys/param.h>
#include <sys/stat.h>
+#include <sys/types.h>
#include <sys/uio.h>
+#include <capsicum_helpers.h>
#include <ctype.h>
+#include <dirent.h>
#include <err.h>
#include <grp.h>
#include <locale.h>
@@ -68,13 +71,27 @@
static char *mbuf;
static int
-ttystat(char *line)
+ttystat(char *line,int fd)
{
struct stat sb;
char ttybuf[MAXPATHLEN];
+ int fd2;
+ char *p;
+ char device[MAXNAMLEN] = _PATH_DEV;
+ char rel_path[1024];
+
+ strcpy(rel_path,"./");
+ strlcat(device, line, sizeof(device));
+ p = device + sizeof(_PATH_DEV) - 1;
+ if (strncmp(p, "pts/", 4) == 0)
+ p += 4;
+ if (strchr(p, '/') != NULL)
+ return -1;
+ strcat(rel_path, p);
(void)snprintf(ttybuf, sizeof(ttybuf), "%s%s", _PATH_DEV, line);
- if (stat(ttybuf, &sb) == 0) {
+ fd2 = openat(fd,rel_path,O_RDONLY);
+ if (fstat(fd2, &sb) == 0) {
return (0);
} else
return (-1);
@@ -92,9 +109,20 @@
char **np;
const char *p;
struct passwd *pw;
+ int devfd;
(void)setlocale(LC_CTYPE, "");
+ /*
+ * Cache NLS data, for strerror, for err(3), before entering capability
+ * mode.
+ */
+ caph_cache_catpages();
+ caph_cache_tzdata();
+ setutxent();
+ devfd = open("/dev/pts/", O_RDONLY|O_NONBLOCK,0);
+ if (devfd < 0)
+ err(1, "open(/dev)");
while ((ch = getopt(argc, argv, "g:n")) != -1)
switch (ch) {
case 'n':
@@ -134,7 +162,7 @@
while ((utmp = getutxent()) != NULL) {
if (utmp->ut_type != USER_PROCESS)
continue;
- if (ttystat(utmp->ut_line) != 0)
+ if (ttystat(utmp->ut_line,devfd) != 0)
continue;
if (grouplist) {
ingroup = 0;
@@ -158,9 +186,10 @@
if (ingroup == 0)
continue;
}
- if ((p = ttymsg(&iov, 1, utmp->ut_line, 60*5)) != NULL)
+ if ((p = ttymsg(&iov, 1, utmp->ut_line, 60*5, devfd)) != NULL)
warnx("%s", p);
}
+ (void)close(devfd);
exit(0);
}
@@ -187,12 +216,29 @@
const char *tty;
const char *whom;
gid_t egid;
+ cap_rights_t rights;
(void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
err(1, "can't open temporary file");
(void)unlink(tmpname);
+ cap_rights_init(&rights, CAP_FSTAT, CAP_IOCTL, CAP_READ,
+ CAP_SEEK,CAP_WRITE);
+ if (caph_rights_limit(fd, &rights) == -1)
+ err(1, "unable to limit capability rights");
+ if (fname) {
+ egid = getegid();
+ setegid(getgid());
+ if (freopen(fname, "r", stdin) == NULL)
+ err(1, "can't read %s", fname);
+ if (setegid(egid) != 0)
+ err(1, "setegid failed");
+ }
+
+ if (caph_enter() < 0)
+ err(1, "unable to enter capability mode");
+
if (!nobanner) {
tty = ttyname(STDERR_FILENO);
if (tty == NULL)
@@ -223,14 +269,6 @@
}
(void)fwprintf(fp, L"%79s\r\n", " ");
- if (fname) {
- egid = getegid();
- setegid(getgid());
- if (freopen(fname, "r", stdin) == NULL)
- err(1, "can't read %s", fname);
- if (setegid(egid) != 0)
- err(1, "setegid failed");
- }
cnt = 0;
while (fgetws(lbuf, sizeof(lbuf)/sizeof(wchar_t), stdin)) {
for (p = lbuf; (ch = *p) != L'\0'; ++p, ++cnt) {

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