dm-stripe: fix a possible integer overflow

JIRA: https://issues.redhat.com/browse/RHEL-119008
Upstream Status: kernel/git/torvalds/linux.git

commit 1071d56
Author: Mikulas Patocka <mpatocka@redhat.com>
Date:   Mon Aug 11 13:17:32 2025 +0200

    dm-stripe: fix a possible integer overflow

    There's a possible integer overflow in stripe_io_hints if we have too
    large chunk size. Test if the overflow happened, and if it did, don't set
    limits->io_min and limits->io_opt;

    Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
    Reviewed-by: John Garry <john.g.garry@oracle.com>
    Suggested-by: Dongsheng Yang <dongsheng.yang@linux.dev>
    Cc: stable@vger.kernel.org

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>

Author: bmarzins

drivers/md/dm-stripe.c

@@ -456,11 +456,15 @@ static void stripe_io_hints(struct dm_target *ti,
 			    struct queue_limits *limits)
 {
 	struct stripe_c *sc = ti->private;
-	unsigned int chunk_size = sc->chunk_size << SECTOR_SHIFT;
+	unsigned int io_min, io_opt;
 
 	limits->chunk_sectors = sc->chunk_size;
-	limits->io_min = chunk_size;
-	limits->io_opt = chunk_size * sc->stripes;
+
+	if (!check_shl_overflow(sc->chunk_size, SECTOR_SHIFT, &io_min) &&
+	    !check_mul_overflow(io_min, sc->stripes, &io_opt)) {
+		limits->io_min = io_min;
+		limits->io_opt = io_opt;
+	}
 }
 
 static struct target_type stripe_target = {