libselinux: is_selinux_enabled(): drop no-policy-loaded test.
upstream commit 685f4aeeadc0b60f3770404d4f149610d656e3c8.
SELinux can be disabled via the selinux=0 kernel parameter or via
/sys/fs/selinux/disable (triggered by setting SELINUX=disabled in
/etc/selinux/config). In either case, selinuxfs will be unmounted
and unregistered and therefore it is sufficient to check for the
selinuxfs mount. We do not need to check for no-policy-loaded and
treat that as SELinux-disabled anymore; that is a relic of Fedora Core 2
days. Drop the no-policy-loaded test, which was a bit of a hack anyway
(checking whether getcon_raw() returned "kernel" as that can only happen
if no policy is yet loaded and therefore security_sid_to_context() only
has the initial SID name available to return as the context).
May possibly fix https://bugzilla.redhat.com/show_bug.cgi?id=1195074
by virtue of removing the call to getcon_raw() and therefore avoiding
use of tls on is_selinux_enabled() calls. Regardless, it will make
is_selinux_enabled() faster and simpler.
[sds: Adapted for the Android libselinux port. Also drops the
fallback to scanning /proc/filesystems for selinuxfs as this was
already done upstream; init mounts selinuxfs via libselinux prior to any
is_selinux_enabled() checks. The tls bug is not relevant in Android
since the Android libselinux port does not use tls, but this change
is nonetheless useful to optimize is_selinux_enabled().]
Change-Id: Ia8b484a3a2fe7f604b0bfb8f5b109ad7674c1152
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
diff --git a/src/enabled.c b/src/enabled.c
index ab015a4..c60eb19 100644
--- a/src/enabled.c
+++ b/src/enabled.c
@@ -10,56 +10,10 @@
int is_selinux_enabled(void)
{
- char buf[BUFSIZ];
- FILE *fp;
- char *bufp;
- int enabled = 0;
- char * con;
-
/* init_selinuxmnt() gets called before this function. We
* will assume that if a selinux file system is mounted, then
* selinux is enabled. */
- if (selinux_mnt) {
-
- /* Since a file system is mounted, we consider selinux
- * enabled. If getcon fails, selinux is still enabled.
- * We only consider it disabled if no policy is loaded. */
- enabled = 1;
- if (getcon(&con) == 0) {
- if (!strcmp(con, "kernel"))
- enabled = 0;
- freecon(con);
- }
- return enabled;
- }
-
- /* Drop back to detecting it the long way. */
- fp = fopen("/proc/filesystems", "r");
- if (!fp)
- return -1;
-
- while ((bufp = fgets(buf, sizeof buf - 1, fp)) != NULL) {
- if (strstr(buf, "selinuxfs")) {
- enabled = 1;
- break;
- }
- }
-
- if (!bufp)
- goto out;
-
- /* Since an selinux file system is available, we consider
- * selinux enabled. If getcon fails, selinux is still
- * enabled. We only consider it disabled if no policy is loaded. */
- if (getcon(&con) == 0) {
- if (!strcmp(con, "kernel"))
- enabled = 0;
- freecon(con);
- }
-
- out:
- fclose(fp);
- return enabled;
+ return (selinux_mnt ? 1 : 0);
}
hidden_def(is_selinux_enabled)