avformat/avidec: Check nb_streams in read_gab2_sub()

Fixes null pointer dereference
Fixes: 1/null_point.avi

Found-by: 连一汉 <lianyihan@360.cn>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2016-09-28 16:14:08 +02:00
parent 14bac7e00d
commit 2679ad4773

View File

@ -1101,6 +1101,8 @@ static int read_gab2_sub(AVFormatContext *s, AVStream *st, AVPacket *pkt)
goto error;
if (!avformat_open_input(&ast->sub_ctx, "", sub_demuxer, NULL)) {
if (ast->sub_ctx->nb_streams != 1)
goto error;
ff_read_packet(ast->sub_ctx, &ast->sub_pkt);
avcodec_parameters_copy(st->codecpar, ast->sub_ctx->streams[0]->codecpar);
time_base = ast->sub_ctx->streams[0]->time_base;