[PATCH 3.8 076/116] xfs: ioctl check for capabilities in the current user namespace

[Kamal Mostafa]

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

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

From: Dwight Engen <dwight.engen at oracle.com>

commit fd5e2aa8653665ae1cc60f7aca1069abdbcad3f6 upstream.

Use inode_capable() to check if SUID|SGID bits should be cleared to match
similar check in inode_change_ok().

The check for CAP_LINUX_IMMUTABLE was not modified since all other file
systems also check against init_user_ns rather than current_user_ns.

Only allow changing of projid from init_user_ns.

Reviewed-by: Dave Chinner <dchinner at redhat.com>
Reviewed-by: Gao feng <gaofeng at cn.fujitsu.com>
Signed-off-by: Dwight Engen <dwight.engen at oracle.com>
Signed-off-by: Ben Myers <bpm at sgi.com>
[ kamal: 3.8-stable prereq for
  23adbe1 fs,userns: Change inode_capable to capable_wrt_inode_uidgid ]
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/xfs/xfs_ioctl.c  | 11 +++++++++--
 kernel/capability.c |  1 +
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index cdaef2d..ec74a78 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -976,15 +976,22 @@ xfs_ioctl_setattr(
 	 * to the file owner ID, except in cases where the
 	 * CAP_FSETID capability is applicable.
 	 */
-	if (current_fsuid() != ip->i_d.di_uid && !capable(CAP_FOWNER)) {
+	if (!inode_owner_or_capable(VFS_I(ip))) {
 		code = XFS_ERROR(EPERM);
 		goto error_return;
 	}
 
 	/*
 	 * Do a quota reservation only if projid is actually going to change.
+	 * Only allow changing of projid from init_user_ns since it is a
+	 * non user namespace aware identifier.
 	 */
 	if (mask & FSX_PROJID) {
+		if (current_user_ns() != &init_user_ns) {
+			code = XFS_ERROR(EINVAL);
+			goto error_return;
+		}
+
 		if (XFS_IS_QUOTA_RUNNING(mp) &&
 		    XFS_IS_PQUOTA_ON(mp) &&
 		    xfs_get_projid(ip) != fa->fsx_projid) {
@@ -1098,7 +1105,7 @@ xfs_ioctl_setattr(
 		 * cleared upon successful return from chown()
 		 */
 		if ((ip->i_d.di_mode & (S_ISUID|S_ISGID)) &&
-		    !capable(CAP_FSETID))
+		    !inode_capable(VFS_I(ip), CAP_FSETID))
 			ip->i_d.di_mode &= ~(S_ISUID|S_ISGID);
 
 		/*
diff --git a/kernel/capability.c b/kernel/capability.c
index f6c2ce5..a4b6744 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -464,3 +464,4 @@ bool inode_capable(const struct inode *inode, int cap)
 
 	return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid);
 }
+EXPORT_SYMBOL(inode_capable);
-- 
1.9.1