[FFmpeg-devel] [PATCH] lavfi/perlin: Fix out of bounds stack buffer write

[epirat07 at gmail.com]

On 6 Jul 2024, at 11:26, Stefano Sabatini wrote:

> On date Tuesday 2024-07-02 20:38:00 +0200, Marvin Scholz wrote:
>> An incorrect calculation in ff_perlin_init causes a write to the
>> stack array at index 256, which is out of bounds.
>>
>> Fixes: CID1608711
>> ---
>>  libavfilter/perlin.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/libavfilter/perlin.c b/libavfilter/perlin.c
>> index 09bae7ad33..ffad8c1e4e 100644
>> --- a/libavfilter/perlin.c
>> +++ b/libavfilter/perlin.c
>> @@ -129,7 +129,7 @@ int ff_perlin_init(FFPerlin *perlin, double period, int octaves, double persiste
>>          for (i = 0; i < 256; i++) {
>>              unsigned int random_idx = av_lfg_get(&lfg) % (256-i);
>>              uint8_t random_val = random_permutations[random_idx];
>> -            random_permutations[random_idx] = random_permutations[256-i];
>> +            random_permutations[random_idx] = random_permutations[255-i];
>>
>>              perlin->permutations[i] = perlin->permutations[i+256] = random_val;
>>          }
>
> Looks good, thanks.

Please push then, I do not have commit access.

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