[dm-devel] [PATCH] dm-statistics: better argument validation

[Mikulas Patocka]

If the number_of_areas argument was zero, the kernel would crash on
div-by-zero. This patch fixes it.

Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
Cc: stable at vger.kernel.org	# v3.12+

---
 drivers/md/dm-stats.c |    2 ++
 1 file changed, 2 insertions(+)

Index: linux-4.1-rc6/drivers/md/dm-stats.c
===================================================================
--- linux-4.1-rc6.orig/drivers/md/dm-stats.c	2015-06-05 15:39:58.000000000 +0200
+++ linux-4.1-rc6/drivers/md/dm-stats.c	2015-06-05 15:42:09.000000000 +0200
@@ -795,6 +795,8 @@ static int message_stats_create(struct m
 		return -EINVAL;
 
 	if (sscanf(argv[2], "/%u%c", &divisor, &dummy) == 1) {
+		if (!divisor)
+			return -EINVAL;
 		step = end - start;
 		if (do_div(step, divisor))
 			step++;