Fixes: out of array access:
Fixes: 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PNG_fuzzer-6716193709096960
Alternatively it should be possible to limit this to 3 plane RGB 8 /16bit to ensure the size is what it should be
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit d5bae70406)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
They should be treated the same as APNG_DISPOSE_OP_NONE.
Broken in 5663301560.
Fixes#9184.
(cherry picked from commit aa726eaed9)
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Calling av_frame_make_writable() from decoders is tricky, especially
when frame threading is used. It is much simpler and safer to just make
a private copy of the frame.
This is not expected to have a major performance impact, since
APNG_DISPOSE_OP_BACKGROUND is not used often and
av_frame_make_writable() would typically make a copy anyway.
Found-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit b593abda6c)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This data cannot be stored in PNGDecContext.picture, because the
corresponding chunks may be read after the call to
ff_thread_finish_setup(), at which point modifying shared context data
is a race.
Store intermediate state in the context and then write it directly to
the output frame.
Fixes exporting frame metadata after 5663301560Fixes#8972
Found-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
(cherry picked from commit 8d74baccff)
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Do not store the image buffer pointer/linesize in the context, just
access them directly from the frame.
Stop assuming that linesize is the same for the current and last frame.
(cherry picked from commit 89ea5057bf)
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Current code is very confused and confusing. It uses two different
reference frames - "previous" and "last" - when only one is really
necessary. It also confuses the two, leading to incorrect output with
APNG_DISPOSE_OP_PREVIOUS mode.
Fixes#9017.
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.
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>
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)
