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avcodec/c93: Check for block overlap. 

Fixes overlapping memcpy()

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2013-04-16 16:41:21 +02:00
parent e701cd96c2
commit 6b657ac788
1 changed files with 8 additions and 1 deletions
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9
libavcodec/c93.c
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@ -168,7 +168,14 @@ static int decode_frame(AVCodecContext *avctx, void *data,
case C93_4X4_FROM_PREV:
for (j = 0; j < 8; j += 4) {
for (i = 0; i < 8; i += 4) {
offset = bytestream2_get_le16(&gb);
int offset = bytestream2_get_le16(&gb);
int from_x = offset % WIDTH;
int from_y = offset / WIDTH;
if (block_type == C93_4X4_FROM_CURR && from_y == y+j &&
(FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) {
avpriv_request_sample(avctx, "block overlap %d %d %d %d\n", from_x, x+i, from_y, y+j);
return AVERROR_INVALIDDATA;
}
if ((ret = copy_block(avctx, &out[j*stride+i],
copy_from, offset, 4, stride)) < 0)
return ret;