By default now, if AV_EF_CRCCHECK or AV_EF_IGNORE_ERR are enabled the decoder
will skip the chunk and carry on with the next one. This should make the
decoder able to decode more corrupt files because the functions which decode
individual chunks will very likely error out if fed invalid data and stop the
decoding of the entire image.
Fixes: 21089/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APNG_fuzzer-5135981419429888
Fixes: out of array read
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Found while reviewing a patch fixing a similar issue
Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
The current design, where
- proper init is called for the first per-thread context
- first thread's private data is copied into private data for all the
other threads
- a "fixup" function is called for all the other threads to e.g.
allocate dynamically allocated data
is very fragile and hard to follow, so it is abandoned. Instead, the
same init function is used to init each per-thread context. Where
necessary, AVCodecInternal.is_copy can be used to differentiate between
the first thread and the other ones (e.g. for decoding the extradata
just once).
add inner loop specialisations for 2 bpp and 4 bpp
These are all cases for which i found testsamples.
30M cycles -> 5M cycles
Testcase: fate-rgbapng-4816
Testcase: 16097/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APNG_fuzzer-5664690889293824
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
assuming each block contains an empty chunk there has to be at least 8 bytes extra.
Fixes: 15327/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_LSCR_fuzzer-5676669303521280
Fixes: Timeout (11->5sec)
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Fixes: out of array access
Fixes: 15540/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APNG_fuzzer-5684905029140480
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
method 0 (inflate/deflate) is the only specified in the specification and the only supported
Fixes: Timeout
Fixes: 10976/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PNG_fuzzer-5729372588736512
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Fixes tsan warnings in fate-apng:
WARNING: ThreadSanitizer: data race (pid=51230)
Read of size 4 at 0x7d50000042fc by main thread (mutexes: write M1000):
#0 frame_copy_props frame.c:302 (ffmpeg:x86_64+0x1019a35d6)
[..]
Previous write of size 4 at 0x7d50000042fc by thread T1 (mutexes: write M997):
#0 decode_idat_chunk pngdec.c:708 (ffmpeg:x86_64+0x100f5562a)
Fixes a reported (but false) race condition in tsan for fate-apng:
WARNING: ThreadSanitizer: data race (pid=6274)
Read of size 4 at 0x7d680001ec78 by main thread (mutexes: write M1338):
#0 update_thread_context src/libavcodec/pngdec.c:1456 (ffmpeg+0x000000dacf0c)
[..]
Previous write of size 4 at 0x7d680001ec78 by thread T1 (mutexes: write M1335):
#0 decode_idat_chunk src/libavcodec/pngdec.c:737 (ffmpeg+0x000000dae951)
Fixes: runtime error: shift exponent 132 is too large for 32-bit type 'int'
Fixes: 609/clusterfuzz-testcase-4825202619842560
See 11.2.2 IHDR Image header
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This fixes a segmentation fault caused by calling memcpy with NULL as
second argument in handle_p_frame_apng.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
This reverts commit e0c6b32046.
Said commit changed the behavior of the demuxer and decoder in a non
backwards compatible way.
Demuxers should make extradata available at init if possible, and send
new extradata as side data within a packet if needed.
A better fix for the remuxing crash will follow.
Signed-off-by: James Almer <jamrial@gmail.com>
Fixes remuxing apng streams coming from the apng demuxer.
This is a regression since 940b8908b9.
Found-by: James Almer <jamrial@gmail.com>
Reviewed-by: James Almer <jamrial@gmail.com>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
The buffer needs s->bpp bytes, at maximum currently 10.
Assert that s->bpp is not larger.
This fixes a stack buffer overflow.
Reviewed-by: wm4 <nfxjfg@googlemail.com>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Use optional sTER chunk defining side-by-side stereo pair
within "Extensions to the PNG 1.2 Specification", version 1.3.0.
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
Lynne
Michael Niedermayer
Limin Wang
Peter Ross
Anton Khirnov
Steven Liu
Paul B Mahol
Jun Zhao
Nicolas George
Rostislav Pehlivanov
Luca Barbato
Muhammad Faiz
Ronald S. Bultje
Clément Bœsch
Derek Buitenhuis
Diego Biurrun
Andreas Cadhalpun
James Almer
Vittorio Giovara
Matthieu Bouron
Kirill Gavrilov