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FFmpeg/libavcodec/avpacket.c
Clément Bœsch 151b4947e5 lavc/avpacket: fill padding area on side data split. 
The padding data is assumed to be 0 in several places, notably in
subtitles. This problem was not detected with fate-sub-srt test because
the first element of the side data (x1) is 0 in the test, so the
trailing side data present in the packet wasn't read by the decoder. The
issue can be observed with a large enough x1.

It is also noted in FF_INPUT_BUFFER_PADDING_SIZE doxy that MPEG
bitstreams require that padding with 0, so it might fix other issues.
2013-06-01 15:12:49 +02:00

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/*
* AVPacket functions for libavcodec
* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <string.h>
#include "libavutil/avassert.h"
#include "libavutil/common.h"
#include "libavutil/mem.h"
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
void ff_packet_free_side_data(AVPacket *pkt)
{
int i;
for (i = 0; i < pkt->side_data_elems; i++)
av_free(pkt->side_data[i].data);
av_freep(&pkt->side_data);
pkt->side_data_elems = 0;
}
#if FF_API_DESTRUCT_PACKET
void av_destruct_packet(AVPacket *pkt)
{
av_free(pkt->data);
pkt->data = NULL;
pkt->size = 0;
}
/* a dummy destruct callback for the callers that assume AVPacket.destruct ==
* NULL => static data */
static void dummy_destruct_packet(AVPacket *pkt)
{
av_assert0(0);
}
#endif
void av_init_packet(AVPacket *pkt)
{
pkt->pts = AV_NOPTS_VALUE;
pkt->dts = AV_NOPTS_VALUE;
pkt->pos = -1;
pkt->duration = 0;
pkt->convergence_duration = 0;
pkt->flags = 0;
pkt->stream_index = 0;
#if FF_API_DESTRUCT_PACKET
pkt->destruct = NULL;
#endif
pkt->buf = NULL;
pkt->side_data = NULL;
pkt->side_data_elems = 0;
}
int av_new_packet(AVPacket *pkt, int size)
{
AVBufferRef *buf = NULL;
if ((unsigned)size >= (unsigned)size + FF_INPUT_BUFFER_PADDING_SIZE)
return AVERROR(EINVAL);
av_buffer_realloc(&buf, size + FF_INPUT_BUFFER_PADDING_SIZE);
if (!buf)
return AVERROR(ENOMEM);
memset(buf->data + size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
av_init_packet(pkt);
pkt->buf = buf;
pkt->data = buf->data;
pkt->size = size;
#if FF_API_DESTRUCT_PACKET
pkt->destruct = dummy_destruct_packet;
#endif
return 0;
}
void av_shrink_packet(AVPacket *pkt, int size)
{
if (pkt->size <= size)
return;
pkt->size = size;
memset(pkt->data + size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
}
int av_grow_packet(AVPacket *pkt, int grow_by)
{
int new_size;
av_assert0((unsigned)pkt->size <= INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE);
if (!pkt->size)
return av_new_packet(pkt, grow_by);
if ((unsigned)grow_by >
INT_MAX - (pkt->size + FF_INPUT_BUFFER_PADDING_SIZE))
return -1;
new_size = pkt->size + grow_by + FF_INPUT_BUFFER_PADDING_SIZE;
if (pkt->buf) {
int ret = av_buffer_realloc(&pkt->buf, new_size);
if (ret < 0)
return ret;
} else {
pkt->buf = av_buffer_alloc(new_size);
if (!pkt->buf)
return AVERROR(ENOMEM);
memcpy(pkt->buf->data, pkt->data, FFMIN(pkt->size, pkt->size + grow_by));
#if FF_API_DESTRUCT_PACKET
pkt->destruct = dummy_destruct_packet;
#endif
}
pkt->data = pkt->buf->data;
pkt->size += grow_by;
memset(pkt->data + pkt->size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
return 0;
}
int av_packet_from_data(AVPacket *pkt, uint8_t *data, int size)
{
if (size >= INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)
return AVERROR(EINVAL);
pkt->buf = av_buffer_create(data, size + FF_INPUT_BUFFER_PADDING_SIZE,
av_buffer_default_free, NULL, 0);
if (!pkt->buf)
return AVERROR(ENOMEM);
pkt->data = data;
pkt->size = size;
#if FF_API_DESTRUCT_PACKET
pkt->destruct = dummy_destruct_packet;
#endif
return 0;
}
#define ALLOC_MALLOC(data, size) data = av_malloc(size)
#define ALLOC_BUF(data, size) \
do { \
av_buffer_realloc(&pkt->buf, size); \
data = pkt->buf ? pkt->buf->data : NULL; \
} while (0)
#define DUP_DATA(dst, src, size, padding, ALLOC) \
do { \
void *data; \
if (padding) { \
if ((unsigned)(size) > \
(unsigned)(size) + FF_INPUT_BUFFER_PADDING_SIZE) \
goto failed_alloc; \
ALLOC(data, size + FF_INPUT_BUFFER_PADDING_SIZE); \
} else { \
ALLOC(data, size); \
} \
if (!data) \
goto failed_alloc; \
memcpy(data, src, size); \
if (padding) \
memset((uint8_t *)data + size, 0, \
FF_INPUT_BUFFER_PADDING_SIZE); \
dst = data; \
} while (0)
/* Makes duplicates of data, side_data, but does not copy any other fields */
static int copy_packet_data(AVPacket *pkt, AVPacket *src, int dup)
{
pkt->data = NULL;
pkt->side_data = NULL;
if (pkt->buf) {
AVBufferRef *ref = av_buffer_ref(src->buf);
if (!ref)
return AVERROR(ENOMEM);
pkt->buf = ref;
pkt->data = ref->data;
} else {
DUP_DATA(pkt->data, src->data, pkt->size, 1, ALLOC_BUF);
}
#if FF_API_DESTRUCT_PACKET
pkt->destruct = dummy_destruct_packet;
#endif
if (pkt->side_data_elems && dup)
pkt->side_data = src->side_data;
if (pkt->side_data_elems && !dup) {
return av_copy_packet_side_data(pkt, src);
}
return 0;
failed_alloc:
av_destruct_packet(pkt);
return AVERROR(ENOMEM);
}
int av_copy_packet_side_data(AVPacket *pkt, AVPacket *src)
{
if (src->side_data_elems) {
int i;
DUP_DATA(pkt->side_data, src->side_data,
src->side_data_elems * sizeof(*src->side_data), 0, ALLOC_MALLOC);
memset(pkt->side_data, 0,
src->side_data_elems * sizeof(*src->side_data));
for (i = 0; i < src->side_data_elems; i++) {
DUP_DATA(pkt->side_data[i].data, src->side_data[i].data,
src->side_data[i].size, 1, ALLOC_MALLOC);
pkt->side_data[i].size = src->side_data[i].size;
pkt->side_data[i].type = src->side_data[i].type;
}
}
return 0;
failed_alloc:
av_destruct_packet(pkt);
return AVERROR(ENOMEM);
}
int av_dup_packet(AVPacket *pkt)
{
AVPacket tmp_pkt;
if (!pkt->buf && pkt->data
#if FF_API_DESTRUCT_PACKET
&& !pkt->destruct
#endif
) {
tmp_pkt = *pkt;
return copy_packet_data(pkt, &tmp_pkt, 1);
}
return 0;
}
int av_copy_packet(AVPacket *dst, AVPacket *src)
{
*dst = *src;
return copy_packet_data(dst, src, 0);
}
void av_free_packet(AVPacket *pkt)
{
if (pkt) {
int i;
if (pkt->buf)
av_buffer_unref(&pkt->buf);
#if FF_API_DESTRUCT_PACKET
else if (pkt->destruct)
pkt->destruct(pkt);
pkt->destruct = NULL;
#endif
pkt->data = NULL;
pkt->size = 0;
for (i = 0; i < pkt->side_data_elems; i++)
av_free(pkt->side_data[i].data);
av_freep(&pkt->side_data);
pkt->side_data_elems = 0;
}
}
uint8_t *av_packet_new_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
int size)
{
int elems = pkt->side_data_elems;
if ((unsigned)elems + 1 > INT_MAX / sizeof(*pkt->side_data))
return NULL;
if ((unsigned)size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)
return NULL;
pkt->side_data = av_realloc(pkt->side_data,
(elems + 1) * sizeof(*pkt->side_data));
if (!pkt->side_data)
return NULL;
pkt->side_data[elems].data = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
if (!pkt->side_data[elems].data)
return NULL;
pkt->side_data[elems].size = size;
pkt->side_data[elems].type = type;
pkt->side_data_elems++;
return pkt->side_data[elems].data;
}
uint8_t *av_packet_get_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
int *size)
{
int i;
for (i = 0; i < pkt->side_data_elems; i++) {
if (pkt->side_data[i].type == type) {
if (size)
*size = pkt->side_data[i].size;
return pkt->side_data[i].data;
}
}
return NULL;
}
#define FF_MERGE_MARKER 0x8c4d9d108e25e9feULL
int av_packet_merge_side_data(AVPacket *pkt){
if(pkt->side_data_elems){
AVBufferRef *buf;
int i;
uint8_t *p;
uint64_t size= pkt->size + 8LL + FF_INPUT_BUFFER_PADDING_SIZE;
AVPacket old= *pkt;
for (i=0; i<old.side_data_elems; i++) {
size += old.side_data[i].size + 5LL;
}
if (size > INT_MAX)
return AVERROR(EINVAL);
buf = av_buffer_alloc(size);
if (!buf)
return AVERROR(ENOMEM);
pkt->buf = buf;
pkt->data = p = buf->data;
#if FF_API_DESTRUCT_PACKET
pkt->destruct = dummy_destruct_packet;
#endif
pkt->size = size - FF_INPUT_BUFFER_PADDING_SIZE;
bytestream_put_buffer(&p, old.data, old.size);
for (i=old.side_data_elems-1; i>=0; i--) {
bytestream_put_buffer(&p, old.side_data[i].data, old.side_data[i].size);
bytestream_put_be32(&p, old.side_data[i].size);
*p++ = old.side_data[i].type | ((i==old.side_data_elems-1)*128);
}
bytestream_put_be64(&p, FF_MERGE_MARKER);
av_assert0(p-pkt->data == pkt->size);
memset(p, 0, FF_INPUT_BUFFER_PADDING_SIZE);
av_free_packet(&old);
pkt->side_data_elems = 0;
pkt->side_data = NULL;
return 1;
}
return 0;
}
int av_packet_split_side_data(AVPacket *pkt){
if (!pkt->side_data_elems && pkt->size >12 && AV_RB64(pkt->data + pkt->size - 8) == FF_MERGE_MARKER){
int i;
unsigned int size, orig_pktsize = pkt->size;
uint8_t *p;
p = pkt->data + pkt->size - 8 - 5;
for (i=1; ; i++){
size = AV_RB32(p);
if (size>INT_MAX || p - pkt->data < size)
return 0;
if (p[4]&128)
break;
p-= size+5;
}
pkt->side_data = av_malloc(i * sizeof(*pkt->side_data));
if (!pkt->side_data)
return AVERROR(ENOMEM);
p= pkt->data + pkt->size - 8 - 5;
for (i=0; ; i++){
size= AV_RB32(p);
av_assert0(size<=INT_MAX && p - pkt->data >= size);
pkt->side_data[i].data = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
pkt->side_data[i].size = size;
pkt->side_data[i].type = p[4]&127;
if (!pkt->side_data[i].data)
return AVERROR(ENOMEM);
memcpy(pkt->side_data[i].data, p-size, size);
pkt->size -= size + 5;
if(p[4]&128)
break;
p-= size+5;
}
pkt->size -= 8;
/* FFMIN() prevents overflow in case the packet wasn't allocated with
* proper padding.
* If the side data is smaller than the buffer padding size, the
* remaining bytes should have already been filled with zeros by the
* original packet allocation anyway. */
memset(pkt->data + pkt->size, 0,
FFMIN(orig_pktsize - pkt->size, FF_INPUT_BUFFER_PADDING_SIZE));
pkt->side_data_elems = i+1;
return 1;
}
return 0;
}
int av_packet_shrink_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
int size)
{
int i;
for (i = 0; i < pkt->side_data_elems; i++) {
if (pkt->side_data[i].type == type) {
if (size > pkt->side_data[i].size)
return AVERROR(ENOMEM);
pkt->side_data[i].size = size;
return 0;
}
}
return AVERROR(ENOENT);
}
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