Revert "SELinux: do not handle seclabel as a special flag"

This reverts commit 308ab70c.

It breaks my FC6 test box.  /dev/pts is not mounted.  dmesg says

SELinux: mount invalid.  Same superblock, different security settings
for (dev devpts, type devpts)

Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NEric Paris <eparis@redhat.com>

security/selinux/hooks.c

@@ -504,6 +504,9 @@ static int selinux_get_mnt_opts(const struct super_block *sb,
 			opts->num_mnt_opts++;
 		tmp >>= 1;
 	}
+	/* Check if the Label support flag is set */
+	if (sbsec->flags & SBLABEL_MNT)
+		opts->num_mnt_opts++;
 
 	opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC);
 	if (!opts->mnt_opts) {

security/selinux/include/security.h

@@ -43,7 +43,7 @@
 #endif
 
 /* Mask for just the mount related flags */
-#define SE_MNTMASK	0x1f
+#define SE_MNTMASK	0x0f
 /* Super block security struct flags for mount options */
 /* BE CAREFUL, these need to be the low order bits for selinux_get_mnt_opts */
 #define CONTEXT_MNT	0x01