ffmpeg | branch: master | Mark Thompson <s...@jkqxz.net> | Sat May 3 18:44:43 2025 +0100| [ea457e54e1b0e9d1309a85fc783e1433abc4bc53] | committer: Mark Thompson
apv_entropy: Improve robustness to bitstream errors > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ea457e54e1b0e9d1309a85fc783e1433abc4bc53 --- libavcodec/apv_entropy.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/libavcodec/apv_entropy.c b/libavcodec/apv_entropy.c index 00e0b4fbdf..a5648c09b4 100644 --- a/libavcodec/apv_entropy.c +++ b/libavcodec/apv_entropy.c @@ -84,6 +84,14 @@ static unsigned int apv_read_vlc(GetBitContext *gbc, int k_param, next_bits = show_bits(gbc, 16); leading_zeroes = 15 - av_log2(next_bits); + if (leading_zeroes == 0) { + // This can't happen mid-stream because the lookup would + // have resolved a leading one into a shorter code, but it + // can happen if we are hitting the end of the buffer. + // Return an invalid code to propagate as an error. + return APV_MAX_TRANS_COEFF + 1; + } + skip_bits(gbc, leading_zeroes + 1); return (2 << k_param) + @@ -182,6 +190,14 @@ int ff_apv_entropy_decode_block(int16_t *coeff, else level = abs_ac_coeff_minus1 + 1; + if (level < APV_MIN_TRANS_COEFF || + level > APV_MAX_TRANS_COEFF) { + av_log(state->log_ctx, AV_LOG_ERROR, + "Out-of-range AC coefficient value: %d " + "(from prev_level %d abs_ac_coeff_minus1 %d sign_ac_coeff %d)\n", + level, prev_level, abs_ac_coeff_minus1, sign_ac_coeff); + } + coeff[ff_zigzag_direct[scan_pos]] = level; prev_level = abs_ac_coeff_minus1 + 1; _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
