[FFmpeg-devel] [PATCH] interplayacm: check for too large b

[Andreas Cadhalpun]

On 30.10.2016 22:16, Paul B Mahol wrote:
> On 10/30/16, Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> wrote:
>> This fixes out-of-bounds reads.
>>
>> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
>> ---
>>  libavcodec/interplayacm.c | 12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>>
>> diff --git a/libavcodec/interplayacm.c b/libavcodec/interplayacm.c
>> index 0fd3501..0486e00 100644
>> --- a/libavcodec/interplayacm.c
>> +++ b/libavcodec/interplayacm.c
>> @@ -326,6 +326,10 @@ static int t15(InterplayACMContext *s, unsigned ind,
>> unsigned col)
>>      for (i = 0; i < s->rows; i++) {
>>          /* b = (x1) + (x2 * 3) + (x3 * 9) */
>>          b = get_bits(gb, 5);
>> +        if (b > 26) {
>> +            av_log(NULL, AV_LOG_ERROR, "Too large b = %d > 26\n", b);
>> +            return AVERROR_INVALIDDATA;
>> +        }
>>
>>          n1 =  (mul_3x3[b] & 0x0F) - 1;
>>          n2 = ((mul_3x3[b] >> 4) & 0x0F) - 1;
>> @@ -351,6 +355,10 @@ static int t27(InterplayACMContext *s, unsigned ind,
>> unsigned col)
>>      for (i = 0; i < s->rows; i++) {
>>          /* b = (x1) + (x2 * 5) + (x3 * 25) */
>>          b = get_bits(gb, 7);
>> +        if (b > 124) {
>> +            av_log(NULL, AV_LOG_ERROR, "Too large b = %d > 124\n", b);
>> +            return AVERROR_INVALIDDATA;
>> +        }
>>
>>          n1 =  (mul_3x5[b] & 0x0F) - 2;
>>          n2 = ((mul_3x5[b] >> 4) & 0x0F) - 2;
>> @@ -375,6 +383,10 @@ static int t37(InterplayACMContext *s, unsigned ind,
>> unsigned col)
>>      for (i = 0; i < s->rows; i++) {
>>          /* b = (x1) + (x2 * 11) */
>>          b = get_bits(gb, 7);
>> +        if (b > 120) {
>> +            av_log(NULL, AV_LOG_ERROR, "Too large b = %d > 120\n", b);
>> +            return AVERROR_INVALIDDATA;
>> +        }
>>
>>          n1 =  (mul_2x11[b] & 0x0F) - 5;
>>          n2 = ((mul_2x11[b] >> 4) & 0x0F) - 5;
>> --
>> 2.10.1
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>>
> 
> probably ok.

Pushed.

Best regards,
Andreas