apparmor: fix regression in mount mediation when feature set is pinned

jrjohansen · jrjohansen · commit 5b9f57cf47b8 · 2018-01-05T15:07:42.000-08:00
When the mount code was refactored for Labels it was not correctly updated to check whether policy supported mediation of the mount class. This causes a regression when the kernel feature set is reported as supporting mount and policy is pinned to a feature set that does not support mount mediation. BugLink: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=882697#41 Fixes: 2ea3ffb ("apparmor: add mount mediation") Reported-by: Fabian Grünbichler <f.gruenbichler@proxmox.com> Cc: Stable <stable@vger.kernel.org> Signed-off-by: John Johansen <john.johansen@canonical.com>
diff --git a/security/apparmor/mount.c b/security/apparmor/mount.c
@@ -329,6 +329,9 @@ static int match_mnt_path_str(struct aa_profile *profile,
 	AA_BUG(!mntpath);
 	AA_BUG(!buffer);
 
+	if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
+		return 0;
+
 	error = aa_path_name(mntpath, path_flags(profile, mntpath), buffer,
 			     &mntpnt, &info, profile->disconnected);
 	if (error)
@@ -380,6 +383,9 @@ static int match_mnt(struct aa_profile *profile, const struct path *path,
 	AA_BUG(!profile);
 	AA_BUG(devpath && !devbuffer);
 
+	if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
+		return 0;
+
 	if (devpath) {
 		error = aa_path_name(devpath, path_flags(profile, devpath),
 				     devbuffer, &devname, &info,
@@ -558,6 +564,9 @@ static int profile_umount(struct aa_profile *profile, struct path *path,
 	AA_BUG(!profile);
 	AA_BUG(!path);
 
+	if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
+		return 0;
+
 	error = aa_path_name(path, path_flags(profile, path), buffer, &name,
 			     &info, profile->disconnected);
 	if (error)
@@ -613,7 +622,8 @@ static struct aa_label *build_pivotroot(struct aa_profile *profile,
 	AA_BUG(!new_path);
 	AA_BUG(!old_path);
 
-	if (profile_unconfined(profile))
+	if (profile_unconfined(profile) ||
+	    !PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
 		return aa_get_newest_label(&profile->label);
 
 	error = aa_path_name(old_path, path_flags(profile, old_path),
