Lynne via ffmpeg-devel: > On 26/06/2024 01:57, Michael Niedermayer wrote: >> On Wed, Jun 26, 2024 at 01:35:18AM +0200, Lynne via ffmpeg-devel wrote: >>> On 24/06/2024 01:01, Michael Niedermayer wrote: >>>> ff_aac_usac_config_decode() needs AACDecContext to be set but some >>>> callers >>>> pass NULL. >>>> >>>> I have no real testcase to implement/test this, so failing in this case >>>> seems safest. >>>> >>>> Fixes: member access within null pointer of type 'AACDecContext' >>>> (aka 'struct AACDecContext') >>>> Fixes: >>>> 69435/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AAC_LATM_fuzzer-5733527483121664 >>>> >>>> Found-by: continuous fuzzing process >>>> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg >>>> Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> >>>> --- >>>> libavcodec/aac/aacdec_usac.c | 3 +++ >>>> 1 file changed, 3 insertions(+) >>>> >>>> diff --git a/libavcodec/aac/aacdec_usac.c >>>> b/libavcodec/aac/aacdec_usac.c >>>> index 132ffee9c20..4856c1786b7 100644 >>>> --- a/libavcodec/aac/aacdec_usac.c >>>> +++ b/libavcodec/aac/aacdec_usac.c >>>> @@ -348,6 +348,9 @@ int ff_aac_usac_config_decode(AACDecContext *ac, >>>> AVCodecContext *avctx, >>>> int map_pos_set = 0; >>>> uint8_t layout_map[MAX_ELEM_ID*4][3] = { 0 }; >>>> + if (!ac) >>>> + return AVERROR_PATCHWELCOME; >>>> + >>>> memset(usac, 0, sizeof(*usac)); >>>> freq_idx = get_bits(gb, 5); /* usacSamplingFrequencyIndex */ >>> >>> This doesn't seem possible at all. >>> There are 2 callers, parse_audio_preroll and >>> decode_audio_specific_config_gb. Both of these will crash way before the >>> function is called. >>> >>> Could you at least get a backtrace? >> >> sure >> >> libavcodec/aac/aacdec_usac.c:402:39: runtime error: member access >> within null pointer of type 'AACDecContext' (aka 'struct AACDecContext') >> SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior >> libavcodec/aac/aacdec_usac.c:402:39 in >> AddressSanitizer:DEADLYSIGNAL >> ================================================================= >> ==215602==ERROR: AddressSanitizer: SEGV on unknown address >> 0x000000005b10 (pc 0x00000154771e bp 0x7ffcf5049e90 sp 0x7ffcf5049e70 T0) >> ==215602==The signal is caused by a READ memory access. >> #0 0x154771d in av_channel_layout_uninit >> ffmpeg/libavutil/channel_layout.c:439:25 >> #1 0x57346e in ff_aac_usac_config_decode >> ffmpeg/libavcodec/aac/aacdec_usac.c:402:9 >> #2 0x500a0a in decode_audio_specific_config_gb >> ffmpeg/libavcodec/aac/aacdec.c:1050:20 >> #3 0x50a542 in latm_decode_audio_specific_config >> ffmpeg/libavcodec/aac/aacdec_latm.h:80:21 >> #4 0x4f8638 in read_stream_mux_config >> ffmpeg/libavcodec/aac/aacdec_latm.h:160:24 >> #5 0x4f8638 in read_audio_mux_element >> ffmpeg/libavcodec/aac/aacdec_latm.h:233 >> #6 0x4f8638 in latm_decode_frame >> ffmpeg/libavcodec/aac/aacdec_latm.h:275 >> #7 0x68f26f in decode_simple_internal >> ffmpeg/libavcodec/decode.c:429:20 >> #8 0x68f26f in decode_simple_receive_frame >> ffmpeg/libavcodec/decode.c:600 >> #9 0x68f26f in decode_receive_frame_internal >> ffmpeg/libavcodec/decode.c:631 >> #10 0x68dc9d in avcodec_send_packet >> ffmpeg/libavcodec/decode.c:721:15 >> #11 0x4d1e55 in LLVMFuzzerTestOneInput >> ffmpeg/tools/target_dec_fuzzer.c:534:25 >> >> >> [...] >> >> >> >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> >> To unsubscribe, visit link above, or email >> ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > > This patch actually is correct. > USAC in LATM is not supported AFAIK. > > LGTM with a note like: > "Happens only when the LATM decoder is used, and USAC is not supported > in LATM". >
But then it is not PATCHWELCOME, but INVALIDDATA. - Andreas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
