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FFmpeg/libavcodec/cbs.c
Andreas Rheinhardt cda3e8ca04 avcodec/cbs: Fix potential overflow 
The number of bits in a PutBitContext must fit into an int, yet nothing
guaranteed the size argument cbs_write_unit_data() uses in init_put_bits()
to be in the range 0..INT_MAX / 8. This has been changed.

Furthermore, the check 8 * data_size > data_bit_start that there is
data beyond the initial padding when writing mpeg2 or H.264/5 slices
could also overflow, so divide it by 8 to get an equivalent check
without this problem.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2019-11-17 23:31:45 +00:00

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/*
* 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 "config.h"
#include "libavutil/avassert.h"
#include "libavutil/buffer.h"
#include "libavutil/common.h"
#include "cbs.h"
#include "cbs_internal.h"
static const CodedBitstreamType *cbs_type_table[] = {
#if CONFIG_CBS_AV1
&ff_cbs_type_av1,
#endif
#if CONFIG_CBS_H264
&ff_cbs_type_h264,
#endif
#if CONFIG_CBS_H265
&ff_cbs_type_h265,
#endif
#if CONFIG_CBS_JPEG
&ff_cbs_type_jpeg,
#endif
#if CONFIG_CBS_MPEG2
&ff_cbs_type_mpeg2,
#endif
#if CONFIG_CBS_VP9
&ff_cbs_type_vp9,
#endif
};
const enum AVCodecID ff_cbs_all_codec_ids[] = {
#if CONFIG_CBS_AV1
AV_CODEC_ID_AV1,
#endif
#if CONFIG_CBS_H264
AV_CODEC_ID_H264,
#endif
#if CONFIG_CBS_H265
AV_CODEC_ID_H265,
#endif
#if CONFIG_CBS_JPEG
AV_CODEC_ID_MJPEG,
#endif
#if CONFIG_CBS_MPEG2
AV_CODEC_ID_MPEG2VIDEO,
#endif
#if CONFIG_CBS_VP9
AV_CODEC_ID_VP9,
#endif
AV_CODEC_ID_NONE
};
int ff_cbs_init(CodedBitstreamContext **ctx_ptr,
enum AVCodecID codec_id, void *log_ctx)
{
CodedBitstreamContext *ctx;
const CodedBitstreamType *type;
int i;
type = NULL;
for (i = 0; i < FF_ARRAY_ELEMS(cbs_type_table); i++) {
if (cbs_type_table[i]->codec_id == codec_id) {
type = cbs_type_table[i];
break;
}
}
if (!type)
return AVERROR(EINVAL);
ctx = av_mallocz(sizeof(*ctx));
if (!ctx)
return AVERROR(ENOMEM);
ctx->log_ctx = log_ctx;
ctx->codec = type;
if (type->priv_data_size) {
ctx->priv_data = av_mallocz(ctx->codec->priv_data_size);
if (!ctx->priv_data) {
av_freep(&ctx);
return AVERROR(ENOMEM);
}
}
ctx->decompose_unit_types = NULL;
ctx->trace_enable = 0;
ctx->trace_level = AV_LOG_TRACE;
*ctx_ptr = ctx;
return 0;
}
void ff_cbs_close(CodedBitstreamContext **ctx_ptr)
{
CodedBitstreamContext *ctx = *ctx_ptr;
if (!ctx)
return;
if (ctx->codec && ctx->codec->close)
ctx->codec->close(ctx);
av_freep(&ctx->write_buffer);
av_freep(&ctx->priv_data);
av_freep(ctx_ptr);
}
static void cbs_unit_uninit(CodedBitstreamContext *ctx,
CodedBitstreamUnit *unit)
{
av_buffer_unref(&unit->content_ref);
unit->content = NULL;
av_buffer_unref(&unit->data_ref);
unit->data = NULL;
unit->data_size = 0;
unit->data_bit_padding = 0;
}
void ff_cbs_fragment_reset(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag)
{
int i;
for (i = 0; i < frag->nb_units; i++)
cbs_unit_uninit(ctx, &frag->units[i]);
frag->nb_units = 0;
av_buffer_unref(&frag->data_ref);
frag->data = NULL;
frag->data_size = 0;
frag->data_bit_padding = 0;
}
void ff_cbs_fragment_free(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag)
{
ff_cbs_fragment_reset(ctx, frag);
av_freep(&frag->units);
frag->nb_units_allocated = 0;
}
static int cbs_read_fragment_content(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag)
{
int err, i, j;
for (i = 0; i < frag->nb_units; i++) {
CodedBitstreamUnit *unit = &frag->units[i];
if (ctx->decompose_unit_types) {
for (j = 0; j < ctx->nb_decompose_unit_types; j++) {
if (ctx->decompose_unit_types[j] == unit->type)
break;
}
if (j >= ctx->nb_decompose_unit_types)
continue;
}
av_buffer_unref(&unit->content_ref);
unit->content = NULL;
av_assert0(unit->data && unit->data_ref);
err = ctx->codec->read_unit(ctx, unit);
if (err == AVERROR(ENOSYS)) {
av_log(ctx->log_ctx, AV_LOG_VERBOSE,
"Decomposition unimplemented for unit %d "
"(type %"PRIu32").\n", i, unit->type);
} else if (err < 0) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to read unit %d "
"(type %"PRIu32").\n", i, unit->type);
return err;
}
}
return 0;
}
static int cbs_fill_fragment_data(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag,
const uint8_t *data, size_t size)
{
av_assert0(!frag->data && !frag->data_ref);
frag->data_ref =
av_buffer_alloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!frag->data_ref)
return AVERROR(ENOMEM);
frag->data = frag->data_ref->data;
frag->data_size = size;
memcpy(frag->data, data, size);
memset(frag->data + size, 0,
AV_INPUT_BUFFER_PADDING_SIZE);
return 0;
}
int ff_cbs_read_extradata(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag,
const AVCodecParameters *par)
{
int err;
err = cbs_fill_fragment_data(ctx, frag, par->extradata,
par->extradata_size);
if (err < 0)
return err;
err = ctx->codec->split_fragment(ctx, frag, 1);
if (err < 0)
return err;
return cbs_read_fragment_content(ctx, frag);
}
int ff_cbs_read_packet(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag,
const AVPacket *pkt)
{
int err;
if (pkt->buf) {
frag->data_ref = av_buffer_ref(pkt->buf);
if (!frag->data_ref)
return AVERROR(ENOMEM);
frag->data = pkt->data;
frag->data_size = pkt->size;
} else {
err = cbs_fill_fragment_data(ctx, frag, pkt->data, pkt->size);
if (err < 0)
return err;
}
err = ctx->codec->split_fragment(ctx, frag, 0);
if (err < 0)
return err;
return cbs_read_fragment_content(ctx, frag);
}
int ff_cbs_read(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag,
const uint8_t *data, size_t size)
{
int err;
err = cbs_fill_fragment_data(ctx, frag, data, size);
if (err < 0)
return err;
err = ctx->codec->split_fragment(ctx, frag, 0);
if (err < 0)
return err;
return cbs_read_fragment_content(ctx, frag);
}
static int cbs_write_unit_data(CodedBitstreamContext *ctx,
CodedBitstreamUnit *unit)
{
PutBitContext pbc;
int ret;
if (!ctx->write_buffer) {
// Initial write buffer size is 1MB.
ctx->write_buffer_size = 1024 * 1024;
reallocate_and_try_again:
ret = av_reallocp(&ctx->write_buffer, ctx->write_buffer_size);
if (ret < 0) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Unable to allocate a "
"sufficiently large write buffer (last attempt "
"%"SIZE_SPECIFIER" bytes).\n", ctx->write_buffer_size);
return ret;
}
}
init_put_bits(&pbc, ctx->write_buffer, ctx->write_buffer_size);
ret = ctx->codec->write_unit(ctx, unit, &pbc);
if (ret < 0) {
if (ret == AVERROR(ENOSPC)) {
// Overflow.
if (ctx->write_buffer_size == INT_MAX / 8)
return AVERROR(ENOMEM);
ctx->write_buffer_size = FFMIN(2 * ctx->write_buffer_size, INT_MAX / 8);
goto reallocate_and_try_again;
}
// Write failed for some other reason.
return ret;
}
// Overflow but we didn't notice.
av_assert0(put_bits_count(&pbc) <= 8 * ctx->write_buffer_size);
if (put_bits_count(&pbc) % 8)
unit->data_bit_padding = 8 - put_bits_count(&pbc) % 8;
else
unit->data_bit_padding = 0;
flush_put_bits(&pbc);
ret = ff_cbs_alloc_unit_data(ctx, unit, put_bits_count(&pbc) / 8);
if (ret < 0)
return ret;
memcpy(unit->data, ctx->write_buffer, unit->data_size);
return 0;
}
int ff_cbs_write_fragment_data(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag)
{
int err, i;
for (i = 0; i < frag->nb_units; i++) {
CodedBitstreamUnit *unit = &frag->units[i];
if (!unit->content)
continue;
av_buffer_unref(&unit->data_ref);
unit->data = NULL;
err = cbs_write_unit_data(ctx, unit);
if (err < 0) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to write unit %d "
"(type %"PRIu32").\n", i, unit->type);
return err;
}
av_assert0(unit->data && unit->data_ref);
}
av_buffer_unref(&frag->data_ref);
frag->data = NULL;
err = ctx->codec->assemble_fragment(ctx, frag);
if (err < 0) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to assemble fragment.\n");
return err;
}
av_assert0(frag->data && frag->data_ref);
return 0;
}
int ff_cbs_write_extradata(CodedBitstreamContext *ctx,
AVCodecParameters *par,
CodedBitstreamFragment *frag)
{
int err;
err = ff_cbs_write_fragment_data(ctx, frag);
if (err < 0)
return err;
av_freep(&par->extradata);
par->extradata = av_malloc(frag->data_size +
AV_INPUT_BUFFER_PADDING_SIZE);
if (!par->extradata)
return AVERROR(ENOMEM);
memcpy(par->extradata, frag->data, frag->data_size);
memset(par->extradata + frag->data_size, 0,
AV_INPUT_BUFFER_PADDING_SIZE);
par->extradata_size = frag->data_size;
return 0;
}
int ff_cbs_write_packet(CodedBitstreamContext *ctx,
AVPacket *pkt,
CodedBitstreamFragment *frag)
{
AVBufferRef *buf;
int err;
err = ff_cbs_write_fragment_data(ctx, frag);
if (err < 0)
return err;
buf = av_buffer_ref(frag->data_ref);
if (!buf)
return AVERROR(ENOMEM);
av_buffer_unref(&pkt->buf);
pkt->buf = buf;
pkt->data = frag->data;
pkt->size = frag->data_size;
return 0;
}
void ff_cbs_trace_header(CodedBitstreamContext *ctx,
const char *name)
{
if (!ctx->trace_enable)
return;
av_log(ctx->log_ctx, ctx->trace_level, "%s\n", name);
}
void ff_cbs_trace_syntax_element(CodedBitstreamContext *ctx, int position,
const char *str, const int *subscripts,
const char *bits, int64_t value)
{
char name[256];
size_t name_len, bits_len;
int pad, subs, i, j, k, n;
if (!ctx->trace_enable)
return;
av_assert0(value >= INT_MIN && value <= UINT32_MAX);
subs = subscripts ? subscripts[0] : 0;
n = 0;
for (i = j = 0; str[i];) {
if (str[i] == '[') {
if (n < subs) {
++n;
k = snprintf(name + j, sizeof(name) - j, "[%d", subscripts[n]);
av_assert0(k > 0 && j + k < sizeof(name));
j += k;
for (++i; str[i] && str[i] != ']'; i++);
av_assert0(str[i] == ']');
} else {
while (str[i] && str[i] != ']')
name[j++] = str[i++];
av_assert0(str[i] == ']');
}
} else {
av_assert0(j + 1 < sizeof(name));
name[j++] = str[i++];
}
}
av_assert0(j + 1 < sizeof(name));
name[j] = 0;
av_assert0(n == subs);
name_len = strlen(name);
bits_len = strlen(bits);
if (name_len + bits_len > 60)
pad = bits_len + 2;
else
pad = 61 - name_len;
av_log(ctx->log_ctx, ctx->trace_level, "%-10d %s%*s = %"PRId64"\n",
position, name, pad, bits, value);
}
int ff_cbs_read_unsigned(CodedBitstreamContext *ctx, GetBitContext *gbc,
int width, const char *name,
const int *subscripts, uint32_t *write_to,
uint32_t range_min, uint32_t range_max)
{
uint32_t value;
int position;
av_assert0(width > 0 && width <= 32);
if (get_bits_left(gbc) < width) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid value at "
"%s: bitstream ended.\n", name);
return AVERROR_INVALIDDATA;
}
if (ctx->trace_enable)
position = get_bits_count(gbc);
value = get_bits_long(gbc, width);
if (ctx->trace_enable) {
char bits[33];
int i;
for (i = 0; i < width; i++)
bits[i] = value >> (width - i - 1) & 1 ? '1' : '0';
bits[i] = 0;
ff_cbs_trace_syntax_element(ctx, position, name, subscripts,
bits, value);
}
if (value < range_min || value > range_max) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
"%"PRIu32", but must be in [%"PRIu32",%"PRIu32"].\n",
name, value, range_min, range_max);
return AVERROR_INVALIDDATA;
}
*write_to = value;
return 0;
}
int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
int width, const char *name,
const int *subscripts, uint32_t value,
uint32_t range_min, uint32_t range_max)
{
av_assert0(width > 0 && width <= 32);
if (value < range_min || value > range_max) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
"%"PRIu32", but must be in [%"PRIu32",%"PRIu32"].\n",
name, value, range_min, range_max);
return AVERROR_INVALIDDATA;
}
if (put_bits_left(pbc) < width)
return AVERROR(ENOSPC);
if (ctx->trace_enable) {
char bits[33];
int i;
for (i = 0; i < width; i++)
bits[i] = value >> (width - i - 1) & 1 ? '1' : '0';
bits[i] = 0;
ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
name, subscripts, bits, value);
}
if (width < 32)
put_bits(pbc, width, value);
else
put_bits32(pbc, value);
return 0;
}
int ff_cbs_read_signed(CodedBitstreamContext *ctx, GetBitContext *gbc,
int width, const char *name,
const int *subscripts, int32_t *write_to,
int32_t range_min, int32_t range_max)
{
int32_t value;
int position;
av_assert0(width > 0 && width <= 32);
if (get_bits_left(gbc) < width) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid value at "
"%s: bitstream ended.\n", name);
return AVERROR_INVALIDDATA;
}
if (ctx->trace_enable)
position = get_bits_count(gbc);
value = get_sbits_long(gbc, width);
if (ctx->trace_enable) {
char bits[33];
int i;
for (i = 0; i < width; i++)
bits[i] = value & (1U << (width - i - 1)) ? '1' : '0';
bits[i] = 0;
ff_cbs_trace_syntax_element(ctx, position, name, subscripts,
bits, value);
}
if (value < range_min || value > range_max) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
"%"PRId32", but must be in [%"PRId32",%"PRId32"].\n",
name, value, range_min, range_max);
return AVERROR_INVALIDDATA;
}
*write_to = value;
return 0;
}
int ff_cbs_write_signed(CodedBitstreamContext *ctx, PutBitContext *pbc,
int width, const char *name,
const int *subscripts, int32_t value,
int32_t range_min, int32_t range_max)
{
av_assert0(width > 0 && width <= 32);
if (value < range_min || value > range_max) {
av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
"%"PRId32", but must be in [%"PRId32",%"PRId32"].\n",
name, value, range_min, range_max);
return AVERROR_INVALIDDATA;
}
if (put_bits_left(pbc) < width)
return AVERROR(ENOSPC);
if (ctx->trace_enable) {
char bits[33];
int i;
for (i = 0; i < width; i++)
bits[i] = value & (1U << (width - i - 1)) ? '1' : '0';
bits[i] = 0;
ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
name, subscripts, bits, value);
}
if (width < 32)
put_sbits(pbc, width, value);
else
put_bits32(pbc, value);
return 0;
}
int ff_cbs_alloc_unit_content(CodedBitstreamContext *ctx,
CodedBitstreamUnit *unit,
size_t size,
void (*free)(void *opaque, uint8_t *data))
{
av_assert0(!unit->content && !unit->content_ref);
unit->content = av_mallocz(size);
if (!unit->content)
return AVERROR(ENOMEM);
unit->content_ref = av_buffer_create(unit->content, size,
free, NULL, 0);
if (!unit->content_ref) {
av_freep(&unit->content);
return AVERROR(ENOMEM);
}
return 0;
}
int ff_cbs_alloc_unit_data(CodedBitstreamContext *ctx,
CodedBitstreamUnit *unit,
size_t size)
{
av_assert0(!unit->data && !unit->data_ref);
unit->data_ref = av_buffer_alloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!unit->data_ref)
return AVERROR(ENOMEM);
unit->data = unit->data_ref->data;
unit->data_size = size;
memset(unit->data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
return 0;
}
static int cbs_insert_unit(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag,
int position)
{
CodedBitstreamUnit *units;
if (frag->nb_units < frag->nb_units_allocated) {
units = frag->units;
if (position < frag->nb_units)
memmove(units + position + 1, units + position,
(frag->nb_units - position) * sizeof(*units));
} else {
units = av_malloc_array(frag->nb_units + 1, sizeof(*units));
if (!units)
return AVERROR(ENOMEM);
++frag->nb_units_allocated;
if (position > 0)
memcpy(units, frag->units, position * sizeof(*units));
if (position < frag->nb_units)
memcpy(units + position + 1, frag->units + position,
(frag->nb_units - position) * sizeof(*units));
}
memset(units + position, 0, sizeof(*units));
if (units != frag->units) {
av_free(frag->units);
frag->units = units;
}
++frag->nb_units;
return 0;
}
int ff_cbs_insert_unit_content(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag,
int position,
CodedBitstreamUnitType type,
void *content,
AVBufferRef *content_buf)
{
CodedBitstreamUnit *unit;
AVBufferRef *content_ref;
int err;
if (position == -1)
position = frag->nb_units;
av_assert0(position >= 0 && position <= frag->nb_units);
if (content_buf) {
content_ref = av_buffer_ref(content_buf);
if (!content_ref)
return AVERROR(ENOMEM);
} else {
content_ref = NULL;
}
err = cbs_insert_unit(ctx, frag, position);
if (err < 0) {
av_buffer_unref(&content_ref);
return err;
}
unit = &frag->units[position];
unit->type = type;
unit->content = content;
unit->content_ref = content_ref;
return 0;
}
int ff_cbs_insert_unit_data(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag,
int position,
CodedBitstreamUnitType type,
uint8_t *data, size_t data_size,
AVBufferRef *data_buf)
{
CodedBitstreamUnit *unit;
AVBufferRef *data_ref;
int err;
if (position == -1)
position = frag->nb_units;
av_assert0(position >= 0 && position <= frag->nb_units);
if (data_buf)
data_ref = av_buffer_ref(data_buf);
else
data_ref = av_buffer_create(data, data_size, NULL, NULL, 0);
if (!data_ref)
return AVERROR(ENOMEM);
err = cbs_insert_unit(ctx, frag, position);
if (err < 0) {
av_buffer_unref(&data_ref);
return err;
}
unit = &frag->units[position];
unit->type = type;
unit->data = data;
unit->data_size = data_size;
unit->data_ref = data_ref;
return 0;
}
void ff_cbs_delete_unit(CodedBitstreamContext *ctx,
CodedBitstreamFragment *frag,
int position)
{
av_assert0(0 <= position && position < frag->nb_units
&& "Unit to be deleted not in fragment.");
cbs_unit_uninit(ctx, &frag->units[position]);
--frag->nb_units;
if (frag->nb_units > 0)
memmove(frag->units + position,
frag->units + position + 1,
(frag->nb_units - position) * sizeof(*frag->units));
}
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