From fe12aa689003db9b07a6e1b837031dcc57a71435 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 25 Apr 2021 20:45:10 +0200 Subject: [PATCH] avformat/realtextdec: Check the pts difference before using it for the duration computation Fixes: signed integer overflow: 5404200000 - -9223372031709351616 cannot be represented in type 'long' Fixes: 29102/clusterfuzz-testcase-minimized-ffmpeg_dem_REALTEXT_fuzzer-6737340551790592 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavformat/realtextdec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/libavformat/realtextdec.c b/libavformat/realtextdec.c index 22fc58bc99..3aeeee8d1c 100644 --- a/libavformat/realtextdec.c +++ b/libavformat/realtextdec.c @@ -111,10 +111,11 @@ static int realtext_read_header(AVFormatContext *s) if (!merge) { const char *begin = ff_smil_get_attr_ptr(buf.str, "begin"); const char *end = ff_smil_get_attr_ptr(buf.str, "end"); + int64_t endi = end ? read_ts(end) : 0; sub->pos = pos; sub->pts = begin ? read_ts(begin) : 0; - sub->duration = end ? (read_ts(end) - sub->pts) : duration; + sub->duration = (end && endi > sub->pts && endi - (uint64_t)sub->pts <= INT64_MAX) ? endi - sub->pts : duration; } } av_bprint_clear(&buf);