The upload is attacker-supplied and its CONTENT can steer ffmpeg to open other
files or URLs (HLS/concat playlists). Pins -protocol_whitelist file,pipe and
-format_whitelist to the containers real recordings use, before the input
(after -i it would apply to the output).
Verified with the real static ffmpeg 7.0.2 on koala: real AAC .m4a and WAV
still probe/convert; a crafted concat file is rejected with 'Format not on
whitelist'. Note ffmpeg 7.0.2 ALREADY refused the playlists tried without the
whitelist, so the live check cannot prove the whitelist -- the argv unit tests
do; this protects against a different ffmpeg version being put in the image.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
mathiasandClaude Sonnet 5.5
291a360a83