ffmpeg | branch: master | James Almer <jamr...@gmail.com> | Mon Jun 23 12:31:37 2025 -0300| [a7beac704b1c3ba38c487e2fa367bb7a84a6c382] | committer: James Almer
avformat/iamf_parse: prevent overreads in update_extradata Fixes: libavcodec/put_bits.h:232:32: runtime error: shift exponent -19 is negative Fixes: Assertion n>=0 && n<=32 failed at ./libavcodec/get_bits.h:406 Fixes: 398527871/clusterfuzz-testcase-minimized-ffmpeg_dem_IAMF_fuzzer-6602025714647040 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: James Almer <jamr...@gmail.com> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a7beac704b1c3ba38c487e2fa367bb7a84a6c382 --- libavformat/iamf_parse.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/libavformat/iamf_parse.c b/libavformat/iamf_parse.c index 71497876ac..46a74ea679 100644 --- a/libavformat/iamf_parse.c +++ b/libavformat/iamf_parse.c @@ -288,7 +288,7 @@ static int update_extradata(AVCodecParameters *codecpar) uint8_t buf[6]; int size = FFMIN(codecpar->extradata_size, sizeof(buf)); - init_put_bits(&pb, buf, size); + init_put_bits(&pb, buf, sizeof(buf)); ret = init_get_bits8(&gb, codecpar->extradata, size); if (ret < 0) return ret; @@ -304,7 +304,10 @@ static int update_extradata(AVCodecParameters *codecpar) skip_bits(&gb, 4); put_bits(&pb, 4, codecpar->ch_layout.nb_channels); // set channel config - ret = put_bits_left(&pb); + ret = get_bits_left(&gb); + if (ret < 0) + return AVERROR_INVALIDDATA; + ret = FFMIN(ret, put_bits_left(&pb)); while (ret >= 32) { put_bits32(&pb, get_bits_long(&gb, 32)); ret -= 32; @@ -317,9 +320,10 @@ static int update_extradata(AVCodecParameters *codecpar) } case AV_CODEC_ID_FLAC: { uint8_t buf[13]; + int size = FFMIN(codecpar->extradata_size, sizeof(buf)); init_put_bits(&pb, buf, sizeof(buf)); - ret = init_get_bits8(&gb, codecpar->extradata, codecpar->extradata_size); + ret = init_get_bits8(&gb, codecpar->extradata, size); if (ret < 0) return ret; @@ -328,11 +332,14 @@ static int update_extradata(AVCodecParameters *codecpar) put_bits(&pb, 20, get_bits(&gb, 20)); // samplerate skip_bits(&gb, 3); put_bits(&pb, 3, codecpar->ch_layout.nb_channels - 1); - ret = put_bits_left(&pb); + ret = get_bits_left(&gb); + if (ret < 0) + return AVERROR_INVALIDDATA; + ret = FFMIN(ret, put_bits_left(&pb)); put_bits(&pb, ret, get_bits(&gb, ret)); flush_put_bits(&pb); - memcpy(codecpar->extradata, buf, sizeof(buf)); + memcpy(codecpar->extradata, buf, put_bytes_output(&pb)); break; } } _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
