avcodec/ffv1dec: Fix out of array read in slice counting

Fixes: test-201710.mp4

Found-by: 连一汉 <lianyihan@360.cn> and Zhibin Hu
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit c20f4fcb74)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2017-10-09 11:49:28 +02:00
parent d13d3feba2
commit 48933f28c2

View File

@ -699,7 +699,7 @@ static int read_header(FFV1Context *f)
} else {
const uint8_t *p = c->bytestream_end;
for (f->slice_count = 0;
f->slice_count < MAX_SLICES && 3 < p - c->bytestream_start;
f->slice_count < MAX_SLICES && 3 + 5*!!f->ec < p - c->bytestream_start;
f->slice_count++) {
int trailer = 3 + 5*!!f->ec;
int size = AV_RB24(p-trailer);