dm: raid fix write_mostly arg validation

Fix off-by-one error in validation of write_mostly.

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@redhat.com>
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index a002dd8..86df8b2 100644 (file)
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -449,7 +449,7 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
                                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;
                        }