[PATCH 3.2 132/185] dm table: fail dm_table_create on dm_round_upoverflow

From: Ben Hutchings
Date: Sat Dec 28 2013 - 21:42:53 EST

3.2.54-rc1 review patch. If anyone has any objections, please let me know.


From: Mikulas Patocka <mpatocka@xxxxxxxxxx>

commit 5b2d06576c5410c10d95adfd5c4d8b24de861d87 upstream.

The dm_round_up function may overflow to zero. In this case,
dm_table_create() must fail rather than go on to allocate an empty array
with alloc_targets().

This fixes a possible memory corruption that could be caused by passing
too large a number in "param->target_count".

Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
drivers/md/dm-table.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -215,6 +215,11 @@ int dm_table_create(struct dm_table **re

num_targets = dm_round_up(num_targets, KEYS_PER_NODE);

+ if (!num_targets) {
+ kfree(t);
+ return -ENOMEM;
+ }
if (alloc_targets(t, num_targets)) {
t = NULL;

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