[PATCH] drm/amd/display: Avoid reading audio pattern past AUDIO_CHANNELS_COUNT

[Harry Wentland]

On 2022-04-28 13:44, Alex Deucher wrote:
> On Thu, Apr 28, 2022 at 1:41 PM Harry Wentland <harry.wentland at amd.com> wrote:
>>
>> A faulty receiver might report an erroneous channel count. We
>> should guard against reading beyond AUDIO_CHANNELS_COUNT as
>> that would overflow the dpcd_pattern_period array.
>>
>> Signed-off-by: Harry Wentland <harry.wentland at amd.com>
> 
> Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

Thanks. Merged.

Harry

> 
>> ---
>>  drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
>> index c15c46b81111..55a5a6a49fe2 100644
>> --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
>> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
>> @@ -4464,7 +4464,7 @@ static void dp_test_get_audio_test_data(struct dc_link *link, bool disable_video
>>                 &dpcd_pattern_type.value,
>>                 sizeof(dpcd_pattern_type));
>>
>> -       channel_count = dpcd_test_mode.bits.channel_count + 1;
>> +       channel_count = min(dpcd_test_mode.bits.channel_count + 1, AUDIO_CHANNELS_COUNT);
>>
>>         // read pattern periods for requested channels when sawTooth pattern is requested
>>         if (dpcd_pattern_type.value == AUDIO_TEST_PATTERN_SAWTOOTH ||
>> --
>> 2.35.1
>>