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

[Vikash Garodia]

On 7/27/2023 10:38 PM, Konrad Dybcio wrote:
> 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"?

I see your point here. Possibly subtracting with sizeof(*wr_ptr) instead of "1"
would be appropriate. Similarly for read queue handling.

- Vikash

> Konrad