releases/3.4.75/dm-table-fail-dm_table_create-on-dm_round_up-overflow.patch

   1 From 5b2d06576c5410c10d95adfd5c4d8b24de861d87 Mon Sep 17 00:00:00 2001
   2 From: Mikulas Patocka <mpatocka@redhat.com>
   3 Date: Fri, 22 Nov 2013 19:52:06 -0500
   4 Subject: dm table: fail dm_table_create on dm_round_up overflow
   5
   6 From: Mikulas Patocka <mpatocka@redhat.com>
   7
   8 commit 5b2d06576c5410c10d95adfd5c4d8b24de861d87 upstream.
   9
  10 The dm_round_up function may overflow to zero.  In this case,
  11 dm_table_create() must fail rather than go on to allocate an empty array
  12 with alloc_targets().
  13
  14 This fixes a possible memory corruption that could be caused by passing
  15 too large a number in "param->target_count".
  16
  17 Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
  18 Signed-off-by: Mike Snitzer <snitzer@redhat.com>
  19 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  20
  21 ---
  22  drivers/md/dm-table.c |    5 +++++
  23  1 file changed, 5 insertions(+)
  24
  25 --- a/drivers/md/dm-table.c
  26 +++ b/drivers/md/dm-table.c
  27 @@ -215,6 +215,11 @@ int dm_table_create(struct dm_table **re
  28
  29         num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
  30
  31 +       if (!num_targets) {
  32 +               kfree(t);
  33 +               return -ENOMEM;
  34 +       }
  35 +
  36         if (alloc_targets(t, num_targets)) {
  37                 kfree(t);
  38                 t = NULL;