[3.16.y-ckt stable] Patch "selinux: fix setting of security labels on NFS" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    selinux: fix setting of security labels on NFS

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt15.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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>From 98af651c215522f9a9bcf37a6b493abb2c72b531 Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields" <bfields at redhat.com>
Date: Thu, 4 Jun 2015 15:57:25 -0400
Subject: selinux: fix setting of security labels on NFS

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>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques 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 a2aa95ecd1d5..9a23a7cccdc4 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -394,7 +394,8 @@ 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*/