RDMA/mlx5: Fix integer overflow while resizing CQ

The user can provide very large cqe_size which will cause to integer
overflow as it can be seen in the following UBSAN warning:

Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/hw/mlx5/cq.c b/drivers/infiniband/hw/mlx5/cq.c
index b5cfdaa..15457c9 100644 (file)
--- a/drivers/infiniband/hw/mlx5/cq.c
+++ b/drivers/infiniband/hw/mlx5/cq.c
@@ -1178,7 +1178,12 @@ static int resize_user(struct mlx5_ib_dev *dev, struct mlx5_ib_cq *cq,
        if (ucmd.reserved0 || ucmd.reserved1)
                return -EINVAL;
 
-       umem = ib_umem_get(context, ucmd.buf_addr, entries * ucmd.cqe_size,
+       /* check multiplication overflow */
+       if (ucmd.cqe_size && SIZE_MAX / ucmd.cqe_size <= entries - 1)
+               return -EINVAL;
+
+       umem = ib_umem_get(context, ucmd.buf_addr,
+                          (size_t)ucmd.cqe_size * entries,
                           IB_ACCESS_LOCAL_WRITE, 1);
        if (IS_ERR(umem)) {
                err = PTR_ERR(umem);