xfs: check for possible overflow in xfs_ioc_trim

If range.start or range.minlen is bigger than filesystem size, return
invalid value error. This fixes possible overflow in BTOBB macro when
passed value was nearly ULLONG_MAX.

Signed-off-by: Tomas Racek <tracek@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
index f9c3fe304a17..69cf4fcde03e 100644
--- a/fs/xfs/xfs_discard.c
+++ b/fs/xfs/xfs_discard.c
@@ -179,12 +179,14 @@ xfs_ioc_trim(
          * used by the fstrim application.  In the end it really doesn't
          * matter as trimming blocks is an advisory interface.
          */
+        if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
+            range.minlen > XFS_FSB_TO_B(mp, XFS_ALLOC_AG_MAX_USABLE(mp)))
+                return -XFS_ERROR(EINVAL);
+
         start = BTOBB(range.start);
         end = start + BTOBBT(range.len) - 1;
         minlen = BTOBB(max_t(u64, granularity, range.minlen));
 
-        if (XFS_BB_TO_FSB(mp, start) >= mp->m_sb.sb_dblocks)
-                return -XFS_ERROR(EINVAL);
         if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
                 end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;