Re: [PATCH 4/5 v4] accel/qaic: move and expand integer overflow checks for map_user_pages()

[Pranjal Ramajor Asha Kanojiya]

On 7/11/2023 1:51 PM, Dan Carpenter wrote:

The integer overflow checking for find_and_map_user_pages() was done in
encode_dma().  Presumably this was to do it before the allocation.  But
it's not super important that the failure path is a fast path and it
hurts readability to put the check so far from the where the variable is
used.

Move the check to find_and_map_user_pages() instead and add some more
additional potential integer overflow checks.

Fixes: 129776ac2e38 ("accel/qaic: Add control path")
Signed-off-by: Dan Carpenter <dan.carpen...@linaro.org>
---
no change

  drivers/accel/qaic/qaic_control.c | 9 ++++++---
  1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/accel/qaic/qaic_control.c 
b/drivers/accel/qaic/qaic_control.c
index 23680f5f1902..d5ce36cb351f 100644
--- a/drivers/accel/qaic/qaic_control.c
+++ b/drivers/accel/qaic/qaic_control.c
@@ -402,6 +402,12 @@ static int find_and_map_user_pages(struct qaic_device 
*qdev,

xfer_start_addr = in_trans->addr + resources->xferred_dma_size; + if (in_trans->size == 0 ||

+           in_trans->addr + in_trans->size < in_trans->addr ||
+           in_trans->addr + resources->xferred_dma_size < in_trans->addr ||

Why not use xfer_start_addr ?

+           in_trans->size + offset_in_page(xfer_start_addr) < 
resources->xferred_dma_size)
+               return -EINVAL;
+
        need_pages = DIV_ROUND_UP(in_trans->size + 
offset_in_page(xfer_start_addr) -
                                  resources->xferred_dma_size, PAGE_SIZE);

@@ -564,9 +570,6 @@ static int encode_dma(struct qaic_device *qdev, void *trans, struct wrapper_list

                     QAIC_MANAGE_EXT_MSG_LENGTH)
                return -ENOMEM;

- if (in_trans->addr + in_trans->size < in_trans->addr || !in_trans->size)

-               return -EINVAL;
-
        xfer = kmalloc(sizeof(*xfer), GFP_KERNEL);
        if (!xfer)
                return -ENOMEM;