Commit 72cf81f6 by Serge Hallyn Committed by Stéphane Graber

CVE-2015-1331: lxclock: use /run/lxc/lock rather than /run/lock/lxc

This prevents an unprivileged user to use LXC to create arbitrary file on the filesystem. Signed-off-by: 's avatarSerge Hallyn <serge.hallyn@ubuntu.com> Signed-off-by: 's avatarTyler Hicks <tyhicks@canonical.com> Acked-by: 's avatarStéphane Graber <stgraber@ubuntu.com>
parent f52c0d26
...@@ -103,13 +103,13 @@ static char *lxclock_name(const char *p, const char *n) ...@@ -103,13 +103,13 @@ static char *lxclock_name(const char *p, const char *n)
char *rundir; char *rundir;
/* lockfile will be: /* lockfile will be:
* "/run" + "/lock/lxc/$lxcpath/$lxcname + '\0' if root * "/run" + "/lxc/lock/$lxcpath/$lxcname + '\0' if root
* or * or
* $XDG_RUNTIME_DIR + "/lock/lxc/$lxcpath/$lxcname + '\0' if non-root * $XDG_RUNTIME_DIR + "/lxc/lock/$lxcpath/$lxcname + '\0' if non-root
*/ */
/* length of "/lock/lxc/" + $lxcpath + "/" + "." + $lxcname + '\0' */ /* length of "/lxc/lock/" + $lxcpath + "/" + "." + $lxcname + '\0' */
len = strlen("/lock/lxc/") + strlen(n) + strlen(p) + 3; len = strlen("/lxc/lock/") + strlen(n) + strlen(p) + 3;
rundir = get_rundir(); rundir = get_rundir();
if (!rundir) if (!rundir)
return NULL; return NULL;
...@@ -120,7 +120,7 @@ static char *lxclock_name(const char *p, const char *n) ...@@ -120,7 +120,7 @@ static char *lxclock_name(const char *p, const char *n)
return NULL; return NULL;
} }
ret = snprintf(dest, len, "%s/lock/lxc/%s", rundir, p); ret = snprintf(dest, len, "%s/lxc/lock/%s", rundir, p);
if (ret < 0 || ret >= len) { if (ret < 0 || ret >= len) {
free(dest); free(dest);
free(rundir); free(rundir);
...@@ -128,40 +128,13 @@ static char *lxclock_name(const char *p, const char *n) ...@@ -128,40 +128,13 @@ static char *lxclock_name(const char *p, const char *n)
} }
ret = mkdir_p(dest, 0755); ret = mkdir_p(dest, 0755);
if (ret < 0) { if (ret < 0) {
/* fall back to "/tmp/" + $(id -u) + "/lxc" + $lxcpath + "/" + "." + $lxcname + '\0' free(dest);
* * maximum length of $(id -u) is 10 calculated by (log (2 ** (sizeof(uid_t) * 8) - 1) / log 10 + 1) free(rundir);
* * lxcpath always starts with '/' return NULL;
*/ }
int l2 = 22 + strlen(n) + strlen(p);
if (l2 > len) {
char *d;
d = realloc(dest, l2);
if (!d) {
free(dest);
free(rundir);
return NULL;
}
len = l2;
dest = d;
}
ret = snprintf(dest, len, "/tmp/%d/lxc%s", geteuid(), p);
if (ret < 0 || ret >= len) {
free(dest);
free(rundir);
return NULL;
}
ret = mkdir_p(dest, 0755);
if (ret < 0) {
free(dest);
free(rundir);
return NULL;
}
ret = snprintf(dest, len, "/tmp/%d/lxc%s/.%s", geteuid(), p, n);
} else
ret = snprintf(dest, len, "%s/lock/lxc/%s/.%s", rundir, p, n);
ret = snprintf(dest, len, "%s/lxc/lock/%s/.%s", rundir, p, n);
free(rundir); free(rundir);
if (ret < 0 || ret >= len) { if (ret < 0 || ret >= len) {
free(dest); free(dest);
return NULL; return NULL;
......
...@@ -122,7 +122,7 @@ int main(int argc, char *argv[]) ...@@ -122,7 +122,7 @@ int main(int argc, char *argv[])
exit(1); exit(1);
} }
struct stat sb; struct stat sb;
char *pathname = RUNTIME_PATH "/lock/lxc/var/lib/lxc/"; char *pathname = RUNTIME_PATH "/lxc/lock/var/lib/lxc/";
ret = stat(pathname, &sb); ret = stat(pathname, &sb);
if (ret != 0) { if (ret != 0) {
fprintf(stderr, "%d: filename %s not created\n", __LINE__, fprintf(stderr, "%d: filename %s not created\n", __LINE__,
......
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