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avformat/iamf_parse: prevent overreads in update_extradata

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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 <jamrial@gmail.com>
This commit is contained in:
James Almer
2025-06-23 12:31:37 -03:00
parent f67ca10f2e
commit a7beac704b
1 changed files with 12 additions and 5 deletions
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17
libavformat/iamf_parse.c
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@ -288,7 +288,7 @@ static int update_extradata(AVCodecParameters *codecpar)
uint8_t buf[6]; uint8_t buf[6];
int size = FFMIN(codecpar->extradata_size, sizeof(buf)); 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); ret = init_get_bits8(&gb, codecpar->extradata, size);
if (ret < 0) if (ret < 0)
return ret; return ret;
@ -304,7 +304,10 @@ static int update_extradata(AVCodecParameters *codecpar)
skip_bits(&gb, 4); skip_bits(&gb, 4);
put_bits(&pb, 4, codecpar->ch_layout.nb_channels); // set channel config 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) { while (ret >= 32) {
put_bits32(&pb, get_bits_long(&gb, 32)); put_bits32(&pb, get_bits_long(&gb, 32));
ret -= 32; ret -= 32;
@ -317,9 +320,10 @@ static int update_extradata(AVCodecParameters *codecpar)
} }
case AV_CODEC_ID_FLAC: { case AV_CODEC_ID_FLAC: {
uint8_t buf[13]; uint8_t buf[13];
int size = FFMIN(codecpar->extradata_size, sizeof(buf));
init_put_bits(&pb, buf, 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) if (ret < 0)
return ret; return ret;
@ -328,11 +332,14 @@ static int update_extradata(AVCodecParameters *codecpar)
put_bits(&pb, 20, get_bits(&gb, 20)); // samplerate put_bits(&pb, 20, get_bits(&gb, 20)); // samplerate
skip_bits(&gb, 3); skip_bits(&gb, 3);
put_bits(&pb, 3, codecpar->ch_layout.nb_channels - 1); 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)); put_bits(&pb, ret, get_bits(&gb, ret));
flush_put_bits(&pb); flush_put_bits(&pb);
memcpy(codecpar->extradata, buf, sizeof(buf)); memcpy(codecpar->extradata, buf, put_bytes_output(&pb));
break; break;
} }
} }