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avcodec/c93: Check for block overlap.

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Fixes overlapping memcpy()

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 6b657ac7889738b9ab38924cca4e7c418f6fbc38)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2013-04-16 16:41:21 +02:00
parent a2186a8054
commit 8ded3738d1
1 changed files with 7 additions and 1 deletions
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8
libavcodec/c93.c
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@ -175,7 +175,13 @@ 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)) {
return AVERROR_INVALIDDATA;
}
if ((ret = copy_block(avctx, &out[j*stride+i],
copy_from, offset, 4, stride)) < 0)
return ret;