On 31.10.2016 08:33, Paul B Mahol wrote: > On 10/30/16, Andreas Cadhalpun <andreas.cadhal...@googlemail.com> wrote: >> On 30.10.2016 22:18, Paul B Mahol wrote: >>> On 10/30/16, Andreas Cadhalpun <andreas.cadhal...@googlemail.com> wrote: >>>> This fixes out-of-bounds reads by the bitstream reader. >>>> >>>> Signed-off-by: Andreas Cadhalpun <andreas.cadhal...@googlemail.com> >>>> --- >>>> libavcodec/interplayacm.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/libavcodec/interplayacm.c b/libavcodec/interplayacm.c >>>> index 0486e00..f4a3446 100644 >>>> --- a/libavcodec/interplayacm.c >>>> +++ b/libavcodec/interplayacm.c >>>> @@ -72,7 +72,7 @@ static av_cold int decode_init(AVCodecContext *avctx) >>>> s->block = av_calloc(s->block_len, sizeof(int)); >>>> s->wrapbuf = av_calloc(s->wrapbuf_len, sizeof(int)); >>>> s->ampbuf = av_calloc(0x10000, sizeof(int)); >>>> - s->bitstream = av_calloc(s->max_framesize, sizeof(*s->bitstream)); >>>> + s->bitstream = av_calloc(s->max_framesize + >>>> AV_INPUT_BUFFER_PADDING_SIZE / sizeof(*s->bitstream) + 1, >>> >>> How did you came up with this fix? >>> Little background would help. >> >> The out-of-bounds read happens in get_bits called from linear. >> The buffer passed to init_get_bits8 is &s->bitstream[s->bitstream_index]. >> The get_bits documentation says: >> /** >> * Initialize GetBitContext. >> * @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE >> bytes >> * larger than the actual read bits because some optimized bitstream >> * readers read 32 or 64 bit at once and could read over the end >> * @param byte_size the size of the buffer in bytes >> * @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would >> overflow. >> */ >> static inline int init_get_bits8(GetBitContext *s, const uint8_t *buffer, >> int byte_size) >> >> Increasing the buffer size fixed the problem, so the case seems quite clear. >> >> Best regards, >> Andreas >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> > > ok
Pushed. Best regards, Andreas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
