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eamad: use the bytestream2 API instead of AV_RL 

This is safer and possibly fixes invalid reads on truncated data.

CC:libav-stable@libav.org
This commit is contained in:
Anton Khirnov 2014-07-20 12:06:47 +00:00
parent 7215fcf840
commit 541427ab4d
1 changed files with 20 additions and 17 deletions
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37
libavcodec/eamad.c
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@ -29,6 +29,7 @@
*/
#include "avcodec.h"
#include "bytestream.h"
#include "bswapdsp.h"
#include "get_bits.h"
#include "aandcttab.h"
@ -235,30 +236,32 @@ static int decode_frame(AVCodecContext *avctx,
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
const uint8_t *buf_end = buf+buf_size;
MadContext *s = avctx->priv_data;
AVFrame *frame = data;
GetByteContext gb;
int width, height;
int chunk_type;
int inter, ret;
if (buf_size < 17) {
av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
*got_frame = 0;
return -1;
}
bytestream2_init(&gb, buf, buf_size);
chunk_type = AV_RL32(&buf[0]);
chunk_type = bytestream2_get_le32(&gb);
inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
buf += 8;
bytestream2_skip(&gb, 10);
av_reduce(&avctx->time_base.num, &avctx->time_base.den,
AV_RL16(&buf[6]), 1000, 1<<30);
bytestream2_get_le16(&gb), 1000, 1<<30);
width = AV_RL16(&buf[8]);
height = AV_RL16(&buf[10]);
calc_quant_matrix(s, buf[13]);
buf += 16;
width = bytestream2_get_le16(&gb);
height = bytestream2_get_le16(&gb);
bytestream2_skip(&gb, 1);
calc_quant_matrix(s, bytestream2_get_byte(&gb));
bytestream2_skip(&gb, 2);
if (bytestream2_get_bytes_left(&gb) < 2) {
av_log(avctx, AV_LOG_ERROR, "Input data too small\n");
return AVERROR_INVALIDDATA;
}
if (avctx->width != width || avctx->height != height) {
av_frame_unref(s->last_frame);
@ -285,12 +288,12 @@ static int decode_frame(AVCodecContext *avctx,
}
av_fast_padded_malloc(&s->bitstream_buf, &s->bitstream_buf_size,
buf_end - buf);
bytestream2_get_bytes_left(&gb));
if (!s->bitstream_buf)
return AVERROR(ENOMEM);
s->bbdsp.bswap16_buf(s->bitstream_buf, (const uint16_t *) buf,
(buf_end - buf) / 2);
init_get_bits(&s->gb, s->bitstream_buf, 8*(buf_end-buf));
s->bbdsp.bswap16_buf(s->bitstream_buf, (const uint16_t *)(buf + bytestream2_tell(&gb)),
bytestream2_get_bytes_left(&gb) / 2);
init_get_bits(&s->gb, s->bitstream_buf, 8*(bytestream2_get_bytes_left(&gb)));
for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)