avcodec/agm: Do not crash on invalid codes
authorMichael Niedermayer <michael@niedermayer.cc>
Sun, 21 Apr 2019 09:05:17 +0000 (11:05 +0200)
committerMichael Niedermayer <michael@niedermayer.cc>
Sun, 21 Apr 2019 21:29:04 +0000 (23:29 +0200)
commit158efc045c718054e3fbd7d0a19d8703e2c1b234
tree1b33f5266204c598c89bfe5b8690d58ede8d682e
parentf17e8e90bb1fe5e4db18cc6dde9522417108c7bd
avcodec/agm: Do not crash on invalid codes

I do not know if such vlc trees are allowed in agm, I have no specification
So i do not know if these should be treated as error, or not.
But the code does contain a check for idx < 0 already ...

Fixes: Stack-buffer-overflow in get_tree_codes
Fixes: 14189/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AGM_fuzzer-5745747003179008

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>
libavcodec/agm.c