From aa441ac105328965bb3b7a7a19571fc6446e544b Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 18 Sep 2022 18:35:19 +0200 Subject: [PATCH] avformat/matroskadec: Error out if a timestamp is beyond duration Maybe timestamp / duration validity should be checked earlier Fixes: 50993/clusterfuzz-testcase-minimized-ffmpeg_dem_WEBM_DASH_MANIFEST_fuzzer-6586894739177472 Fixes: signed integer overflow: 0 - -9223372036854775808 cannot be represented in type 'long' Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavformat/matroskadec.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c index 16a3e93611..8b079e1110 100644 --- a/libavformat/matroskadec.c +++ b/libavformat/matroskadec.c @@ -4009,7 +4009,8 @@ typedef struct { /* This function searches all the Cues and returns the CueDesc corresponding to * the timestamp ts. Returned CueDesc will be such that start_time_ns <= ts < - * end_time_ns. All 4 fields will be set to -1 if ts >= file's duration. + * end_time_ns. All 4 fields will be set to -1 if ts >= file's duration or + * if an error occurred. */ static CueDesc get_cue_desc(AVFormatContext *s, int64_t ts, int64_t cues_start) { MatroskaDemuxContext *matroska = s->priv_data; @@ -4028,6 +4029,8 @@ static CueDesc get_cue_desc(AVFormatContext *s, int64_t ts, int64_t cues_start) } } --i; + if (index_entries[i].timestamp > matroska->duration) + return (CueDesc) {-1, -1, -1, -1}; cue_desc.start_time_ns = index_entries[i].timestamp * matroska->time_scale; cue_desc.start_offset = index_entries[i].pos - matroska->segment_start; if (i != nb_index_entries - 1) {