[PATCH 3.4 25/31] dm table: fail dm_table_create on dm_round_up overflow

From: Greg Kroah-Hartman
Date: Wed Dec 18 2013 - 16:09:24 EST


3.4-stable 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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
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)) {
kfree(t);
t = NULL;


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