Re: [PATCH] dm-stripe: fix a possible integer overflow

[Dongsheng Yang]

在 7/7/2025 6:39 PM, Mikulas Patocka 写道:

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 <mpato...@redhat.com>
Cc: sta...@vger.kernel.org

---
  drivers/md/dm-stripe.c |   10 +++++++---
  1 file changed, 7 insertions(+), 3 deletions(-)

Index: linux-2.6/drivers/md/dm-stripe.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-stripe.c       2025-07-06 15:02:23.000000000 
+0200
+++ linux-2.6/drivers/md/dm-stripe.c    2025-07-07 12:32:49.000000000 +0200
@@ -456,10 +456,14 @@ static void stripe_io_hints(struct dm_ta
                            struct queue_limits *limits)
  {
        struct stripe_c *sc = ti->private;
-       unsigned int chunk_size = sc->chunk_size << SECTOR_SHIFT;
+       unsigned int io_min = sc->chunk_size << SECTOR_SHIFT;
+       unsigned int io_opt = io_min * sc->stripes;

- limits->io_min = chunk_size;

-       limits->io_opt = chunk_size * sc->stripes;
+       if (io_min >> SECTOR_SHIFT == sc->chunk_size &&
+           io_opt / sc->stripes == io_min) {
+               limits->io_min = io_min;
+               limits->io_opt = io_opt;
+       }

Hi Mikulas,

    What about using check_xxx_overflow() ? something like:


    if (check_shl_overflow(sc->chunk_size, SECTOR_SHIFT, &io_min))
        return;


    if (check_mul_overflow(io_min, sc->stripes, &io_opt))
        return;

    limits->io_min = io_min;
    limits->io_opt = io_opt;

  }

static struct target_type stripe_target = {