dm raid: fix a couple integer overflows

My static checker complains that if "num_raid_params" is UINT_MAX then
the "if (num_raid_params + 1 > argc) {" check doesn't work as intended.

The other change is that I moved the "if (argc != (num_raid_devs * 2))"
condition forward a few lines so it was before the call to
context_alloc().  If we had an integer overflow inside that function
then it would lead to an immediate crash.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 7 insertions, 9 deletions

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 07c0fa0fa284..41acc9dd7342 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -1243,7 +1243,7 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
         argv++;
 
         /* Skip over RAID params for now and find out # of devices */
-        if (num_raid_params + 1 > argc) {
+        if (num_raid_params >= argc) {
                 ti->error = "Arguments do not agree with counts given";
                 return -EINVAL;
         }
@@ -1254,6 +1254,12 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
                 return -EINVAL;
         }
 
+        argc -= num_raid_params + 1; /* +1: we already have num_raid_devs */
+        if (argc != (num_raid_devs * 2)) {
+                ti->error = "Supplied RAID devices does not match the count given";
+                return -EINVAL;
+        }
+
         rs = context_alloc(ti, rt, (unsigned)num_raid_devs);
         if (IS_ERR(rs))
                 return PTR_ERR(rs);
@@ -1262,16 +1268,8 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
         if (ret)
                 goto bad;
 
-        ret = -EINVAL;
-
-        argc -= num_raid_params + 1; /* +1: we already have num_raid_devs */
         argv += num_raid_params + 1;
 
-        if (argc != (num_raid_devs * 2)) {
-                ti->error = "Supplied RAID devices does not match the count given";
-                goto bad;
-        }
-
         ret = dev_parms(rs, argv);
         if (ret)
                 goto bad;