[FFmpeg-cvslog] avformat/mpegts: Limit iterations of get_packet_size()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu Oct 22 20:41:48 2020 +0200| [4bdb7966fac87fdbf76f4828a3fbe14fd874679c] | committer: Michael Niedermayer

avformat/mpegts: Limit iterations of get_packet_size()

This is a pathological case where the fuzzer provides only 2 bytes per iteration.

Fixes: Timeout (>30 -> 0.9sec)
Fixes: 26488/clusterfuzz-testcase-minimized-ffmpeg_dem_MPEGTS_fuzzer-5911031077142528

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4bdb7966fac87fdbf76f4828a3fbe14fd874679c
---

 libavformat/mpegts.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index a2003c6632..7549fc91c9 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -609,8 +609,9 @@ static int get_packet_size(AVFormatContext* s)
     /*init buffer to store stream for probing */
     uint8_t buf[PROBE_PACKET_MAX_BUF] = {0};
     int buf_size = 0;
+    int max_iterations = 16;
 
-    while (buf_size < PROBE_PACKET_MAX_BUF) {
+    while (buf_size < PROBE_PACKET_MAX_BUF && max_iterations--) {
         ret = avio_read_partial(s->pb, buf + buf_size, PROBE_PACKET_MAX_BUF - buf_size);
         if (ret < 0)
             return AVERROR_INVALIDDATA;