[FFmpeg-trac] #8221(undetermined:new): left shift of negative value bugs in libavcodec/vc2enc.c

[FFmpeg]

#8221: left shift of negative value bugs in libavcodec/vc2enc.c
-------------------------------------+-------------------------------------
             Reporter:  Suhwan       |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:  ubsan        |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 There're two left shift of negative value bugs in libavcodec/vc2enc.c
 {{{
 libavcodec/vc2enc.c:660:51: runtime error: left shift of negative value -2
 SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior
 libavcodec/vc2enc.c:660:51 in
 libavcodec/vc2enc.c:661:51: runtime error: left shift of negative value -1
 SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior
 libavcodec/vc2enc.c:661:51 in
 }}}
 How to reproduce:
 {{{
 % ffmpeg_g -t 1 -y -r 118 -i $PoC -target vcd -loglevel 0 -map 0 -c:v:0
 vc2 -disposition:v:105 ppm -disposition:a:103 alias_pix -aframes 118 -r 71
 -b:v 440k tmp.mp4

 ffmpeg version N-95199-g9847380f5f Copyright (c) 2000-2019 the FFmpeg
 developers
   built with clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
   configuration: --cc=clang --cxx=clang++ --ld=clang --enable-debug
 --toolchain=clang-usan
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8221>
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