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h264: limit allowed pred modes in ff_h264_check_intra_pred_mode() to 3

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Higher modes are not allowed for 16x16/chroma, which is what this
function is used for. Otherwise this function would return 0 (vertical
prediction) for invalid higher modes, which could result in invalid
reads.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC:libav-stable@libav.org
This commit is contained in:
Anton Khirnov 2013-11-28 10:54:35 +01:00 committed by Reinhard Tartler
parent c4033cd4eb
commit 51ae8e26af
1 changed files with 3 additions and 3 deletions
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6
libavcodec/h264.c
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@ -107,10 +107,10 @@ int ff_h264_check_intra4x4_pred_mode(H264Context *h){
*/
int ff_h264_check_intra_pred_mode(H264Context *h, int mode, int is_chroma){
MpegEncContext * const s = &h->s;
static const int8_t top [7]= {LEFT_DC_PRED8x8, 1,-1,-1};
static const int8_t left[7]= { TOP_DC_PRED8x8,-1, 2,-1,DC_128_PRED8x8};
static const int8_t top[4] = { LEFT_DC_PRED8x8, 1, -1, -1 };
static const int8_t left[5] = { TOP_DC_PRED8x8, -1, 2, -1, DC_128_PRED8x8 };
if(mode > 6U) {
if(mode > 3U) {
av_log(h->s.avctx, AV_LOG_ERROR, "out of range intra chroma pred mode at %d %d\n", s->mb_x, s->mb_y);
return -1;
}