avformat/gxf: Check pkt_len

Fixes: Infinite loop
Fixes: 26576/clusterfuzz-testcase-minimized-ffmpeg_dem_GXF_fuzzer-4823080360476672

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2020-10-26 21:08:55 +01:00
parent 0ba71a72d3
commit dad9a86ca7

View File

@ -285,9 +285,12 @@ static void gxf_track_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si
static void gxf_read_index(AVFormatContext *s, int pkt_len) {
AVIOContext *pb = s->pb;
AVStream *st;
uint32_t fields_per_map = avio_rl32(pb);
uint32_t map_cnt = avio_rl32(pb);
uint32_t fields_per_map, map_cnt;
int i;
if (pkt_len < 8)
return;
fields_per_map = avio_rl32(pb);
map_cnt = avio_rl32(pb);
pkt_len -= 8;
if ((s->flags & AVFMT_FLAG_IGNIDX) || !s->streams) {
avio_skip(pb, pkt_len);