[PATCH 4.0 35/55] selinux: fix setting of security labels on NFS

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

From: "J. Bruce Fields" <bfields@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@redhat.com>
Cc: David Quigley <dpquigl@davequigley.com>
Reported-by: Richard Chan <rc556677@outlook.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
[PM: added the stable dependency]
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 security/selinux/hooks.c |    1 +
 1 file changed, 1 insertion(+)

--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -404,6 +404,7 @@ static int selinux_is_sblabel_mnt(struct
 	return sbsec->behavior == SECURITY_FS_USE_XATTR ||
 		sbsec->behavior == SECURITY_FS_USE_TRANS ||
 		sbsec->behavior == SECURITY_FS_USE_TASK ||
+		sbsec->behavior == SECURITY_FS_USE_NATIVE ||
 		/* Special handling. Genfs but also in-core setxattr handler */
 		!strcmp(sb->s_type->name, "sysfs") ||
 		!strcmp(sb->s_type->name, "pstore") ||