avformat/matroskadec: Check pre_ns for overflow

Fixes: signed integer overflow: -3483479120376300096 - 7442323944145700864 cannot be represented in type 'long'
Fixes: 383187489/clusterfuzz-testcase-minimized-ffmpeg_dem_WEBM_DASH_MANIFEST_fuzzer-4561470580391936

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2024-12-11 21:36:11 +01:00
parent 8f4eb0fe03
commit 361d24e6d9
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@ -4618,9 +4618,10 @@ static int64_t webm_dash_manifest_compute_bandwidth(AVFormatContext *s, int64_t
// The prebuffer ends in the last Cue. Estimate how much data was
// prebuffered.
pre_bytes = desc_end.end_offset - desc_end.start_offset;
pre_ns = desc_end.end_time_ns - desc_end.start_time_ns;
if (pre_ns <= 0)
if (desc_end.end_time_ns <= desc_end.start_time_ns ||
desc_end.end_time_ns - (uint64_t)desc_end.start_time_ns > INT64_MAX)
return -1;
pre_ns = desc_end.end_time_ns - desc_end.start_time_ns;
pre_sec = pre_ns / nano_seconds_per_second;
prebuffer_bytes +=
pre_bytes * ((temp_prebuffer_ns / nano_seconds_per_second) / pre_sec);