LSM/SELinux: Interfaces to allow FS to control mount options

Introduce new LSM interfaces to allow an FS to deal with their own mount
options.  This includes a new string parsing function exported from the
LSM that an FS can use to get a security data blob and a new security
data blob.  This is particularly useful for an FS which uses binary
mount data, like NFS, which does not pass strings into the vfs to be
handled by the loaded LSM.  Also fix a BUG() in both SELinux and SMACK
when dealing with binary mount data.  If the binary mount data is less
than one page the copy_page() in security_sb_copy_data() can cause an
illegal page fault and boom.  Remove all NFSisms from the SELinux code
since they were broken by past NFS changes.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 1 insertions, 8 deletions

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 770eb06..0241fd35 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -189,17 +189,10 @@ static void smack_sb_free_security(struct super_block *sb)
  * Copy the Smack specific mount options out of the mount
  * options list.
  */
-static int smack_sb_copy_data(struct file_system_type *type, void *orig,
-			      void *smackopts)
+static int smack_sb_copy_data(char *orig, char *smackopts)
 {
 	char *cp, *commap, *otheropts, *dp;
 
-	/* Binary mount data: just copy */
-	if (type->fs_flags & FS_BINARY_MOUNTDATA) {
-		copy_page(smackopts, orig);
-		return 0;
-	}
-
 	otheropts = (char *)get_zeroed_page(GFP_KERNEL);
 	if (otheropts == NULL)
 		return -ENOMEM;