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 <michael@niedermayer.cc>
(cherry picked from commit fe12aa6890)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2021-04-25 20:45:10 +02:00
parent 7da58f8fe7
commit 8b8e5ccdc2
1 changed files with 2 additions and 1 deletions

View File

@ -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);