From 5038933977d06d1048b41d71e0ada4d1ac536ddc Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 5 Feb 2022 20:37:22 +0100 Subject: avformat/matroskadec: Check desc_bytes Fixes: Division by 0 Fixes: 44035/clusterfuzz-testcase-minimized-ffmpeg_dem_WEBM_DASH_MANIFEST_fuzzer-4826721386364928 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavformat/matroskadec.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'libavformat') diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c index 628cfdaf56..31e5111225 100644 --- a/libavformat/matroskadec.c +++ b/libavformat/matroskadec.c @@ -4216,12 +4216,16 @@ static int64_t webm_dash_manifest_compute_bandwidth(AVFormatContext *s, int64_t do { int64_t desc_bytes = desc_end.end_offset - desc_beg.start_offset; int64_t desc_ns = desc_end.end_time_ns - desc_beg.start_time_ns; - double desc_sec = desc_ns / nano_seconds_per_second; - double calc_bits_per_second = (desc_bytes * 8) / desc_sec; + double desc_sec, calc_bits_per_second, percent, mod_bits_per_second; + if (desc_bytes <= 0) + return -1; + + desc_sec = desc_ns / nano_seconds_per_second; + calc_bits_per_second = (desc_bytes * 8) / desc_sec; // Drop the bps by the percentage of bytes buffered. - double percent = (desc_bytes - prebuffer_bytes) / desc_bytes; - double mod_bits_per_second = calc_bits_per_second * percent; + percent = (desc_bytes - prebuffer_bytes) / desc_bytes; + mod_bits_per_second = calc_bits_per_second * percent; if (prebuffer < desc_sec) { double search_sec = -- cgit v1.2.3