magicyuv: invalid read with fuzzed file

[ami_stuff]

aaa@aaa-VirtualBox /media/sdb1 $ valgrind --leak-check=full ffmpeg/ffmpeg_g -i f/400_f.avi -f null -
==14158== Memcheck, a memory error detector
==14158== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==14158== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info
==14158== Command: ffmpeg/ffmpeg_g -i f/400_f.avi -f null -
==14158== 
ffmpeg version 3.0.git Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 5.3.0 (Ubuntu 5.3.0-3ubuntu1~14.04) 20151204
  configuration: --disable-ffprobe --disable-ffserver --enable-gpl
  libavutil      55. 24.100 / 55. 24.100
  libavcodec     57. 43.100 / 57. 43.100
  libavformat    57. 37.101 / 57. 37.101
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 46.100 /  6. 46.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Input #0, avi, from 'f/400_f.avi':
  Duration: 00:00:00.83, start: 0.000000, bitrate: 8581 kb/s
    Stream #0:0: Video: magicyuv (MAGY / 0x5947414D), gray, 320x240, 8945 kb/s, 23.97 fps, 23.97 tbr, 23.97 tbn
[null @ 0x42f7ae0] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf57.37.101
    Stream #0:0: Video: wrapped_avframe, gray, 320x240, q=2-31, 200 kb/s, 23.97 fps, 23.97 tbn
    Metadata:
      encoder         : Lavc57.43.100 wrapped_avframe
Stream mapping:
  Stream #0:0 -> #0:0 (magicyuv (native) -> wrapped_avframe (native))
Press [q] to stop, [?] for help
[magicyuv @ 0x43436c0] unsupported format: 0x2B is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[magicyuv @ 0x43436c0] If you want to help, upload a sample of this file to ftp://upload.ffmpeg.org/incoming/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
Error while decoding stream #0:0: Not yet implemented in FFmpeg, patches welcome
Error while decoding stream #0:0: Invalid data found when processing input
[magicyuv @ 0x43450a0] unknown prediction: 34881 is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[magicyuv @ 0x43450a0] If you want to help, upload a sample of this file to ftp://upload.ffmpeg.org/incoming/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
[magicyuv @ 0x43450a0] unknown prediction: 53133 is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[magicyuv @ 0x43450a0] If you want to help, upload a sample of this file to ftp://upload.ffmpeg.org/incoming/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
[magicyuv @ 0x43450a0] unknown prediction: 23843 is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[magicyuv @ 0x43450a0] If you want to help, upload a sample of this file to ftp://upload.ffmpeg.org/incoming/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
[magicyuv @ 0x43450a0] unknown prediction: 55638 is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[magicyuv @ 0x43450a0] If you want to help, upload a sample of this file to ftp://upload.ffmpeg.org/incoming/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
[magicyuv @ 0x43450a0] unknown prediction: 20291 is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[magicyuv @ 0x43450a0] If you want to help, upload a sample of this file to ftp://upload.ffmpeg.org/incoming/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
==14158== Thread 14:
==14158== Invalid read of size 4
==14158==    at 0x85BC0AF: decode_slice (magicyuv.c:140)
==14158==    by 0x8743699: avcodec_default_execute2 (utils.c:1002)
==14158==    by 0x85BCC21: decode_frame (magicyuv.c:401)
==14158==    by 0x867D8AC: frame_worker_thread (pthread_frame.c:146)
==14158==    by 0x40ECF6F: start_thread (pthread_create.c:312)
==14158==    by 0x41EDBED: clone (clone.S:129)
==14158==  Address 0x44b7a1b is 46,227 bytes inside a block of size 46,230 alloc'd
==14158==    at 0x402A17C: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==14158==    by 0x402C3AF: realloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==14158==    by 0x8B9898F: av_buffer_realloc (buffer.c:176)
==14158==    by 0x8370C84: packet_alloc (avpacket.c:77)
==14158==    by 0x8370C84: av_new_packet (avpacket.c:89)
==14158==    by 0x8370C84: av_grow_packet (avpacket.c:114)
==14158==    by 0x83133F9: append_packet_chunked (utils.c:239)
==14158==    by 0x820370E: avi_read_packet (avidec.c:1418)
==14158==    by 0x8314951: ff_read_packet (utils.c:759)
==14158==    by 0x831835B: read_frame_internal (utils.c:1457)
==14158==    by 0x83196CF: av_read_frame (utils.c:1642)
==14158==    by 0x80D32FE: get_input_packet (ffmpeg.c:3673)
==14158==    by 0x80BD826: process_input (ffmpeg.c:3793)
==14158==    by 0x80BD826: transcode_step (ffmpeg.c:4103)
==14158==    by 0x80BD826: transcode (ffmpeg.c:4157)
==14158==    by 0x80BD826: main (ffmpeg.c:4350)
==14158== 
[magicyuv @ 0x4348480] unknown prediction: 56173 is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[magicyuv @ 0x4348480] If you want to help, upload a sample of this file to ftp://upload.ffmpeg.org/incoming/ and contact the ffmpeg-devel mailing list. (ffmpeg-devel@ffmpeg.org)
Error while decoding stream #0:0: Invalid data found when processing input
frame=   14 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.79 bitrate=N/A speed=2.28x    
video:5kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
==14158== 
==14158== HEAP SUMMARY:
==14158==     in use at exit: 24 bytes in 1 blocks
==14158==   total heap usage: 1,498 allocs, 1,497 frees, 2,425,852 bytes allocated
==14158== 
==14158== LEAK SUMMARY:
==14158==    definitely lost: 0 bytes in 0 blocks
==14158==    indirectly lost: 0 bytes in 0 blocks
==14158==      possibly lost: 0 bytes in 0 blocks
==14158==    still reachable: 24 bytes in 1 blocks
==14158==         suppressed: 0 bytes in 0 blocks
==14158== Reachable blocks (those to which a pointer was found) are not shown.
==14158== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==14158== 
==14158== For counts of detected and suppressed errors, rerun with: -v
==14158== ERROR SUMMARY: 340 errors from 1 contexts (suppressed: 0 from 0)

[Elon Musk]

Fixed in e8a236add82e668c3e665a4ab38c91d875047e43.