dm stripe: avoid divide by zero with invalid stripe count

If a table containing zero as stripe count is passed into stripe_ctr
the code attempts to divide by zero.

This patch changes DM_TABLE_LOAD to return -EINVAL if the stripe count
is zero.

We now get the following error messages:
  device-mapper: table: 253:0: striped: Invalid stripe count
  device-mapper: ioctl: error adding target to table

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Cc: stable@kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index e0efc1a..bd58703 100644 (file)
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -110,7 +110,7 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
        }
 
        stripes = simple_strtoul(argv[0], &end, 10);
-       if (*end) {
+       if (!stripes || *end) {
                ti->error = "Invalid stripe count";
                return -EINVAL;
        }