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ffmpeg
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tgq: convert to bytestream2 API. 

This protects against input buffer overreads.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
This commit is contained in:
Ronald S. Bultje 2012-03-06 14:18:32 -08:00
parent aed9da20af
commit 1255eed533
1 changed files with 28 additions and 28 deletions
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56
libavcodec/eatgq.c
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@ -43,6 +43,7 @@ typedef struct TgqContext {
ScanTable scantable;
int qtable[64];
DECLARE_ALIGNED(16, DCTELEM, block)[6][64];
GetByteContext gb;
} TgqContext;
static av_cold int tgq_decode_init(AVCodecContext *avctx){
@ -141,39 +142,36 @@ static void tgq_idct_put_mb_dconly(TgqContext *s, int mb_x, int mb_y, const int8
}
}
static void tgq_decode_mb(TgqContext *s, int mb_y, int mb_x, const uint8_t **bs, const uint8_t *buf_end){
static void tgq_decode_mb(TgqContext *s, int mb_y, int mb_x){
int mode;
int i;
int8_t dc[6];
mode = bytestream_get_byte(bs);
if (mode>buf_end-*bs) {
av_log(s->avctx, AV_LOG_ERROR, "truncated macroblock\n");
return;
}
mode = bytestream2_get_byte(&s->gb);
if (mode>12) {
GetBitContext gb;
init_get_bits(&gb, *bs, mode*8);
init_get_bits(&gb, s->gb.buffer, FFMIN(s->gb.buffer_end - s->gb.buffer, mode) * 8);
for(i=0; i<6; i++)
tgq_decode_block(s, s->block[i], &gb);
tgq_idct_put_mb(s, s->block, mb_x, mb_y);
bytestream2_skip(&s->gb, mode);
}else{
if (mode==3) {
memset(dc, (*bs)[0], 4);
dc[4] = (*bs)[1];
dc[5] = (*bs)[2];
memset(dc, bytestream2_get_byte(&s->gb), 4);
dc[4] = bytestream2_get_byte(&s->gb);
dc[5] = bytestream2_get_byte(&s->gb);
}else if (mode==6) {
memcpy(dc, *bs, 6);
bytestream2_get_buffer(&s->gb, dc, 6);
}else if (mode==12) {
for(i=0; i<6; i++)
dc[i] = (*bs)[i*2];
for (i = 0; i < 6; i++) {
dc[i] = bytestream2_get_byte(&s->gb);
bytestream2_skip(&s->gb, 1);
}
}else{
av_log(s->avctx, AV_LOG_ERROR, "unsupported mb mode %i\n", mode);
}
tgq_idct_put_mb_dconly(s, mb_x, mb_y, dc);
}
*bs += mode;
}
static void tgq_calculate_qtable(TgqContext *s, int quant){
@ -193,28 +191,30 @@ static int tgq_decode_frame(AVCodecContext *avctx,
AVPacket *avpkt){
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
const uint8_t *buf_start = buf;
const uint8_t *buf_end = buf + buf_size;
TgqContext *s = avctx->priv_data;
int x,y;
int big_endian = AV_RL32(&buf[4]) > 0x000FFFFF;
buf += 8;
if(8>buf_end-buf) {
if (buf_size < 16) {
av_log(avctx, AV_LOG_WARNING, "truncated header\n");
return -1;
}
s->width = big_endian ? AV_RB16(&buf[0]) : AV_RL16(&buf[0]);
s->height = big_endian ? AV_RB16(&buf[2]) : AV_RL16(&buf[2]);
bytestream2_init(&s->gb, buf + 8, buf_size - 8);
if (big_endian) {
s->width = bytestream2_get_be16u(&s->gb);
s->height = bytestream2_get_be16u(&s->gb);
} else {
s->width = bytestream2_get_le16u(&s->gb);
s->height = bytestream2_get_le16u(&s->gb);
}
if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
avcodec_set_dimensions(s->avctx, s->width, s->height);
if (s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
}
tgq_calculate_qtable(s, buf[4]);
buf += 8;
tgq_calculate_qtable(s, bytestream2_get_byteu(&s->gb));
bytestream2_skip(&s->gb, 3);
if (!s->frame.data[0]) {
s->frame.key_frame = 1;
@ -226,14 +226,14 @@ static int tgq_decode_frame(AVCodecContext *avctx,
}
}
for (y=0; y<(avctx->height+15)/16; y++)
for (x=0; x<(avctx->width+15)/16; x++)
tgq_decode_mb(s, y, x, &buf, buf_end);
for (y = 0; y < FFALIGN(avctx->height, 16) >> 4; y++)
for (x = 0; x < FFALIGN(avctx->width, 16) >> 4; x++)
tgq_decode_mb(s, y, x);
*data_size = sizeof(AVFrame);
*(AVFrame*)data = s->frame;
return buf-buf_start;
return avpkt->size;
}
static av_cold int tgq_decode_end(AVCodecContext *avctx){