xfs: ioctl check for capabilities in the current user namespace

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@redhat.com>
Reviewed-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

2 files changed, 10 insertions, 2 deletions

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index e9c17e2ed6d7..999c1efd6af5 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1015,15 +1015,22 @@ 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) {
@@ -1137,7 +1144,7 @@ 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 f6c2ce5701e1..a4b67446dc87 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);