On Wed, Jun 26, 2024 at 08:58:27AM +0200, Lynne via ffmpeg-devel wrote: > 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".
will apply with this thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB There will always be a question for which you do not know the correct answer.
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