Commit dd4c1b7d authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer

dm stats: fix divide by zero if 'number_of_areas' arg is zero

If the number_of_areas argument was zero the kernel would crash on
div-by-zero.  Add better input validation.
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # v3.12+
parent bccab6a0
...@@ -792,6 +792,8 @@ static int message_stats_create(struct mapped_device *md, ...@@ -792,6 +792,8 @@ static int message_stats_create(struct mapped_device *md,
return -EINVAL; return -EINVAL;
if (sscanf(argv[2], "/%u%c", &divisor, &dummy) == 1) { if (sscanf(argv[2], "/%u%c", &divisor, &dummy) == 1) {
if (!divisor)
return -EINVAL;
step = end - start; step = end - start;
if (do_div(step, divisor)) if (do_div(step, divisor))
step++; step++;
......
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