avcodec/ylc: Check count in build_vlc()

Fixes: runtime error: signed integer overflow: 211633430 + 2147483647 cannot be represented in type 'int'
Fixes: 1874/clusterfuzz-testcase-minimized-5037763613163520

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 2017-05-28 17:20:42 +02:00
parent b9c032ebc0
commit 67b30decf7
1 changed files with 5 additions and 1 deletions

View File

@ -109,7 +109,7 @@ static int build_vlc(AVCodecContext *avctx, VLC *vlc, const uint32_t *table)
int new_node = j;
int first_node = cur_node;
int second_node = cur_node;
int nd, st;
unsigned nd, st;
nodes[cur_node].count = -1;
@ -133,6 +133,10 @@ static int build_vlc(AVCodecContext *avctx, VLC *vlc, const uint32_t *table)
st = nodes[first_node].count;
nodes[second_node].count = 0;
nodes[first_node].count = 0;
if (nd >= UINT32_MAX - st) {
av_log(avctx, AV_LOG_ERROR, "count overflow\n");
return AVERROR_INVALIDDATA;
}
nodes[cur_node].count = nd + st;
nodes[cur_node].sym = -1;
nodes[cur_node].n0 = cur_node;