[PATCH 3.19.y-ckt 083/251] selinux: fix setting of security labels on NFS

[Kamal Mostafa]

3.19.8-ckt4 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: "J. Bruce Fields" <bfields at redhat.com>

commit 9fc2b4b436cff7d8403034676014f1be9d534942 upstream.

Before calling into the filesystem, vfs_setxattr calls
security_inode_setxattr, which ends up calling selinux_inode_setxattr in
our case.  That returns -EOPNOTSUPP whenever SBLABEL_MNT is not set.
SBLABEL_MNT was supposed to be set by sb_finish_set_opts, which sets it
only if selinux_is_sblabel_mnt returns true.

The selinux_is_sblabel_mnt logic was broken by eadcabc697e9 "SELinux: do
all flags twiddling in one place", which didn't take into the account
the SECURITY_FS_USE_NATIVE behavior that had been introduced for nfs
with eb9ae686507b "SELinux: Add new labeling type native labels".

This caused setxattr's of security labels over NFSv4.2 to fail.

Cc: Eric Paris <eparis at redhat.com>
Cc: David Quigley <dpquigl at davequigley.com>
Reported-by: Richard Chan <rc556677 at outlook.com>
Signed-off-by: J. Bruce Fields <bfields at redhat.com>
Acked-by: Stephen Smalley <sds at tycho.nsa.gov>
[PM: added the stable dependency]
Signed-off-by: Paul Moore <pmoore at redhat.com>
[ kamal: backport to 3.19-stable: context ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 security/selinux/hooks.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 6da7532..7634300 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -403,7 +403,8 @@ static int selinux_is_sblabel_mnt(struct super_block *sb)
 
 	if (sbsec->behavior == SECURITY_FS_USE_XATTR ||
 	    sbsec->behavior == SECURITY_FS_USE_TRANS ||
-	    sbsec->behavior == SECURITY_FS_USE_TASK)
+	    sbsec->behavior == SECURITY_FS_USE_TASK ||
+	    sbsec->behavior == SECURITY_FS_USE_NATIVE)
 		return 1;
 
 	/* Special handling for sysfs. Is genfs but also has setxattr handler*/
-- 
1.9.1