[dm-devel] [PATCH] DM RAID: Fix off-by-one comparison.

[jbrassow at redhat.com]

Fix off-by-one comparison.

The user-supplied value given for the 'write_mostly' argument must be an
index starting at 0.  The validation of the supplied argument failed to
check for 'N' ('>' vs '>='), which would have caused an access beyond the
end of the array.

Reported-by: Doug Ledford <dledford at redhat.com>
Signed-off-by: Jonathan Brassow <jbrassow at redhat.com>


Index: linux-upstream/drivers/md/dm-raid.c
===================================================================
--- linux-upstream.orig/drivers/md/dm-raid.c
+++ linux-upstream/drivers/md/dm-raid.c
@@ -449,7 +449,7 @@ static int parse_raid_params(struct raid
 				rs->ti->error = "write_mostly option is only valid for RAID1";
 				return -EINVAL;
 			}
-			if (value > rs->md.raid_disks) {
+			if (value >= rs->md.raid_disks) {
 				rs->ti->error = "Invalid write_mostly drive index given";
 				return -EINVAL;
 			}