Re: [PATCH 1/4] venus: hfi: add checks to perform sanity on queue pointers

[Konrad Dybcio]

On 27.07.2023 06:34, Vikash Garodia wrote:
> Read and write pointers are used to track the packet index in the memory
> shared between video driver and firmware. There is a possibility of OOB
> access if the read or write pointer goes beyond the queue memory size.
> Add checks for the read and write pointer to avoid OOB access.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: d96d3f30c0f2 ("[media] media: venus: hfi: add Venus HFI files")
> Signed-off-by: Vikash Garodia <quic_vgarodia@xxxxxxxxxxx>
> ---
>  drivers/media/platform/qcom/venus/hfi_venus.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/media/platform/qcom/venus/hfi_venus.c b/drivers/media/platform/qcom/venus/hfi_venus.c
> index f0b4638..dc228c4 100644
> --- a/drivers/media/platform/qcom/venus/hfi_venus.c
> +++ b/drivers/media/platform/qcom/venus/hfi_venus.c
> @@ -206,6 +206,10 @@ static int venus_write_queue(struct venus_hfi_device *hdev,
>  
>  	new_wr_idx = wr_idx + dwords;
>  	wr_ptr = (u32 *)(queue->qmem.kva + (wr_idx << 2));
> +
> +	if (wr_ptr < (u32 *)queue->qmem.kva || wr_ptr > (u32 *)(queue->qmem.kva + queue->qmem.size))
Shouldn't the cases on the right side of the OR operator include a
"- 1"?

Konrad