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ffmpeg/libavcodec/pngenc.c
Clément Bœsch 57ec555e8e avcodec/pngenc: fix invalid read in sub filter. 
First pixel was computed based on invalid address read, and then
corrected by the following memcpy. After the commit, it's not computed
anymore, and memcpy fills the appropriate area.

Fixes Ticket #3387
2014-02-23 20:40:52 +01:00

531 lines
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C
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/*
* PNG image format
* Copyright (c) 2003 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 "avcodec.h"
#include "internal.h"
#include "bytestream.h"
#include "dsputil.h"
#include "png.h"
#include "libavutil/avassert.h"
#include "libavutil/opt.h"
#include <zlib.h>
#define IOBUF_SIZE 4096
typedef struct PNGEncContext {
AVClass *class;
DSPContext dsp;
uint8_t *bytestream;
uint8_t *bytestream_start;
uint8_t *bytestream_end;
int filter_type;
z_stream zstream;
uint8_t buf[IOBUF_SIZE];
int dpi; ///< Physical pixel density, in dots per inch, if set
int dpm; ///< Physical pixel density, in dots per meter, if set
} PNGEncContext;
static void png_get_interlaced_row(uint8_t *dst, int row_size,
int bits_per_pixel, int pass,
const uint8_t *src, int width)
{
int x, mask, dst_x, j, b, bpp;
uint8_t *d;
const uint8_t *s;
static const int masks[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
mask = masks[pass];
switch(bits_per_pixel) {
case 1:
memset(dst, 0, row_size);
dst_x = 0;
for(x = 0; x < width; x++) {
j = (x & 7);
if ((mask << j) & 0x80) {
b = (src[x >> 3] >> (7 - j)) & 1;
dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
dst_x++;
}
}
break;
default:
bpp = bits_per_pixel >> 3;
d = dst;
s = src;
for(x = 0; x < width; x++) {
j = x & 7;
if ((mask << j) & 0x80) {
memcpy(d, s, bpp);
d += bpp;
}
s += bpp;
}
break;
}
}
static void sub_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
{
int i;
for(i = 0; i < w; i++) {
int a, b, c, p, pa, pb, pc;
a = src[i - bpp];
b = top[i];
c = top[i - bpp];
p = b - c;
pc = a - c;
pa = abs(p);
pb = abs(pc);
pc = abs(p + pc);
if (pa <= pb && pa <= pc)
p = a;
else if (pb <= pc)
p = b;
else
p = c;
dst[i] = src[i] - p;
}
}
static void sub_left_prediction(DSPContext *dsp, uint8_t *dst, const uint8_t *src, int bpp, int size)
{
const uint8_t *src1 = src + bpp;
const uint8_t *src2 = src;
int x, unaligned_w;
memcpy(dst, src, bpp);
dst += bpp;
size -= bpp;
unaligned_w = FFMIN(32 - bpp, size);
for (x = 0; x < unaligned_w; x++)
*dst++ = *src1++ - *src2++;
size -= unaligned_w;
dsp->diff_bytes(dst, src1, src2, size);
}
static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type,
uint8_t *src, uint8_t *top, int size, int bpp)
{
int i;
switch(filter_type) {
case PNG_FILTER_VALUE_NONE:
memcpy(dst, src, size);
break;
case PNG_FILTER_VALUE_SUB:
sub_left_prediction(dsp, dst, src, bpp, size);
break;
case PNG_FILTER_VALUE_UP:
dsp->diff_bytes(dst, src, top, size);
break;
case PNG_FILTER_VALUE_AVG:
for(i = 0; i < bpp; i++)
dst[i] = src[i] - (top[i] >> 1);
for(; i < size; i++)
dst[i] = src[i] - ((src[i-bpp] + top[i]) >> 1);
break;
case PNG_FILTER_VALUE_PAETH:
for(i = 0; i < bpp; i++)
dst[i] = src[i] - top[i];
sub_png_paeth_prediction(dst+i, src+i, top+i, size-i, bpp);
break;
}
}
static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst,
uint8_t *src, uint8_t *top, int size, int bpp)
{
int pred = s->filter_type;
av_assert0(bpp || !pred);
if(!top && pred)
pred = PNG_FILTER_VALUE_SUB;
if(pred == PNG_FILTER_VALUE_MIXED) {
int i;
int cost, bcost = INT_MAX;
uint8_t *buf1 = dst, *buf2 = dst + size + 16;
for(pred=0; pred<5; pred++) {
png_filter_row(&s->dsp, buf1+1, pred, src, top, size, bpp);
buf1[0] = pred;
cost = 0;
for(i=0; i<=size; i++)
cost += abs((int8_t)buf1[i]);
if(cost < bcost) {
bcost = cost;
FFSWAP(uint8_t*, buf1, buf2);
}
}
return buf2;
} else {
png_filter_row(&s->dsp, dst+1, pred, src, top, size, bpp);
dst[0] = pred;
return dst;
}
}
static void png_write_chunk(uint8_t **f, uint32_t tag,
const uint8_t *buf, int length)
{
uint32_t crc;
uint8_t tagbuf[4];
bytestream_put_be32(f, length);
crc = crc32(0, Z_NULL, 0);
AV_WL32(tagbuf, tag);
crc = crc32(crc, tagbuf, 4);
bytestream_put_be32(f, av_bswap32(tag));
if (length > 0) {
crc = crc32(crc, buf, length);
memcpy(*f, buf, length);
*f += length;
}
bytestream_put_be32(f, crc);
}
/* XXX: do filtering */
static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)
{
int ret;
s->zstream.avail_in = size;
s->zstream.next_in = (uint8_t *)data;
while (s->zstream.avail_in > 0) {
ret = deflate(&s->zstream, Z_NO_FLUSH);
if (ret != Z_OK)
return -1;
if (s->zstream.avail_out == 0) {
if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
s->zstream.avail_out = IOBUF_SIZE;
s->zstream.next_out = s->buf;
}
}
return 0;
}
static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
const AVFrame *pict, int *got_packet)
{
PNGEncContext *s = avctx->priv_data;
const AVFrame * const p = pict;
int bit_depth, color_type, y, len, row_size, ret, is_progressive;
int bits_per_pixel, pass_row_size, enc_row_size;
int64_t max_packet_size;
int compression_level;
uint8_t *ptr, *top;
uint8_t *crow_base = NULL, *crow_buf, *crow;
uint8_t *progressive_buf = NULL;
uint8_t *top_buf = NULL;
is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
switch(avctx->pix_fmt) {
case AV_PIX_FMT_RGBA64BE:
bit_depth = 16;
color_type = PNG_COLOR_TYPE_RGB_ALPHA;
break;
case AV_PIX_FMT_RGB48BE:
bit_depth = 16;
color_type = PNG_COLOR_TYPE_RGB;
break;
case AV_PIX_FMT_RGBA:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGB_ALPHA;
break;
case AV_PIX_FMT_RGB24:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGB;
break;
case AV_PIX_FMT_GRAY16BE:
bit_depth = 16;
color_type = PNG_COLOR_TYPE_GRAY;
break;
case AV_PIX_FMT_GRAY8:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_GRAY;
break;
case AV_PIX_FMT_GRAY8A:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
break;
case AV_PIX_FMT_MONOBLACK:
bit_depth = 1;
color_type = PNG_COLOR_TYPE_GRAY;
break;
case AV_PIX_FMT_PAL8:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_PALETTE;
break;
default:
return -1;
}
bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth;
row_size = (avctx->width * bits_per_pixel + 7) >> 3;
s->zstream.zalloc = ff_png_zalloc;
s->zstream.zfree = ff_png_zfree;
s->zstream.opaque = NULL;
compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ?
Z_DEFAULT_COMPRESSION :
av_clip(avctx->compression_level, 0, 9);
ret = deflateInit2(&s->zstream, compression_level,
Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
if (ret != Z_OK)
return -1;
enc_row_size = deflateBound(&s->zstream, row_size);
max_packet_size = avctx->height * (int64_t)(enc_row_size +
((enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) * 12)
+ FF_MIN_BUFFER_SIZE;
if (max_packet_size > INT_MAX)
return AVERROR(ENOMEM);
if ((ret = ff_alloc_packet2(avctx, pkt, max_packet_size)) < 0)
return ret;
s->bytestream_start =
s->bytestream = pkt->data;
s->bytestream_end = pkt->data + pkt->size;
crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED));
if (!crow_base)
goto fail;
crow_buf = crow_base + 15; // pixel data should be aligned, but there's a control byte before it
if (is_progressive) {
progressive_buf = av_malloc(row_size + 1);
if (!progressive_buf)
goto fail;
}
if (is_progressive) {
top_buf = av_malloc(row_size + 1);
if (!top_buf)
goto fail;
}
/* write png header */
AV_WB64(s->bytestream, PNGSIG);
s->bytestream += 8;
AV_WB32(s->buf, avctx->width);
AV_WB32(s->buf + 4, avctx->height);
s->buf[8] = bit_depth;
s->buf[9] = color_type;
s->buf[10] = 0; /* compression type */
s->buf[11] = 0; /* filter type */
s->buf[12] = is_progressive; /* interlace type */
png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
if (s->dpm) {
AV_WB32(s->buf, s->dpm);
AV_WB32(s->buf + 4, s->dpm);
s->buf[8] = 1; /* unit specifier is meter */
} else {
AV_WB32(s->buf, avctx->sample_aspect_ratio.num);
AV_WB32(s->buf + 4, avctx->sample_aspect_ratio.den);
s->buf[8] = 0; /* unit specifier is unknown */
}
png_write_chunk(&s->bytestream, MKTAG('p', 'H', 'Y', 's'), s->buf, 9);
/* put the palette if needed */
if (color_type == PNG_COLOR_TYPE_PALETTE) {
int has_alpha, alpha, i;
unsigned int v;
uint32_t *palette;
uint8_t *alpha_ptr;
palette = (uint32_t *)p->data[1];
ptr = s->buf;
alpha_ptr = s->buf + 256 * 3;
has_alpha = 0;
for(i = 0; i < 256; i++) {
v = palette[i];
alpha = v >> 24;
if (alpha != 0xff)
has_alpha = 1;
*alpha_ptr++ = alpha;
bytestream_put_be24(&ptr, v);
}
png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
if (has_alpha) {
png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
}
}
/* now put each row */
s->zstream.avail_out = IOBUF_SIZE;
s->zstream.next_out = s->buf;
if (is_progressive) {
int pass;
for(pass = 0; pass < NB_PASSES; pass++) {
/* NOTE: a pass is completely omitted if no pixels would be
output */
pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width);
if (pass_row_size > 0) {
top = NULL;
for(y = 0; y < avctx->height; y++) {
if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
ptr = p->data[0] + y * p->linesize[0];
FFSWAP(uint8_t*, progressive_buf, top_buf);
png_get_interlaced_row(progressive_buf, pass_row_size,
bits_per_pixel, pass,
ptr, avctx->width);
crow = png_choose_filter(s, crow_buf, progressive_buf, top, pass_row_size, bits_per_pixel>>3);
png_write_row(s, crow, pass_row_size + 1);
top = progressive_buf;
}
}
}
}
} else {
top = NULL;
for(y = 0; y < avctx->height; y++) {
ptr = p->data[0] + y * p->linesize[0];
crow = png_choose_filter(s, crow_buf, ptr, top, row_size, bits_per_pixel>>3);
png_write_row(s, crow, row_size + 1);
top = ptr;
}
}
/* compress last bytes */
for(;;) {
ret = deflate(&s->zstream, Z_FINISH);
if (ret == Z_OK || ret == Z_STREAM_END) {
len = IOBUF_SIZE - s->zstream.avail_out;
if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
}
s->zstream.avail_out = IOBUF_SIZE;
s->zstream.next_out = s->buf;
if (ret == Z_STREAM_END)
break;
} else {
goto fail;
}
}
png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
pkt->size = s->bytestream - s->bytestream_start;
pkt->flags |= AV_PKT_FLAG_KEY;
*got_packet = 1;
ret = 0;
the_end:
av_free(crow_base);
av_free(progressive_buf);
av_free(top_buf);
deflateEnd(&s->zstream);
return ret;
fail:
ret = -1;
goto the_end;
}
static av_cold int png_enc_init(AVCodecContext *avctx){
PNGEncContext *s = avctx->priv_data;
switch(avctx->pix_fmt) {
case AV_PIX_FMT_RGBA:
avctx->bits_per_coded_sample = 32;
break;
case AV_PIX_FMT_RGB24:
avctx->bits_per_coded_sample = 24;
break;
case AV_PIX_FMT_GRAY8:
avctx->bits_per_coded_sample = 0x28;
break;
case AV_PIX_FMT_MONOBLACK:
avctx->bits_per_coded_sample = 1;
break;
case AV_PIX_FMT_PAL8:
avctx->bits_per_coded_sample = 8;
}
avctx->coded_frame = av_frame_alloc();
if (!avctx->coded_frame)
return AVERROR(ENOMEM);
avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
avctx->coded_frame->key_frame = 1;
ff_dsputil_init(&s->dsp, avctx);
s->filter_type = av_clip(avctx->prediction_method, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED);
if(avctx->pix_fmt == AV_PIX_FMT_MONOBLACK)
s->filter_type = PNG_FILTER_VALUE_NONE;
if (s->dpi && s->dpm) {
av_log(avctx, AV_LOG_ERROR, "Only one of 'dpi' or 'dpm' options should be set\n");
return AVERROR(EINVAL);
} else if (s->dpi) {
s->dpm = s->dpi * 10000 / 254;
}
return 0;
}
static av_cold int png_enc_close(AVCodecContext *avctx)
{
av_frame_free(&avctx->coded_frame);
return 0;
}
#define OFFSET(x) offsetof(PNGEncContext, x)
#define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{"dpi", "Set image resolution (in dots per inch)", OFFSET(dpi), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},
{"dpm", "Set image resolution (in dots per meter)", OFFSET(dpm), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},
{ NULL }
};
static const AVClass pngenc_class = {
.class_name = "PNG encoder",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVCodec ff_png_encoder = {
.name = "png",
.long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_PNG,
.priv_data_size = sizeof(PNGEncContext),
.init = png_enc_init,
.close = png_enc_close,
.encode2 = encode_frame,
.capabilities = CODEC_CAP_FRAME_THREADS | CODEC_CAP_INTRA_ONLY,
.pix_fmts = (const enum AVPixelFormat[]){
AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA,
AV_PIX_FMT_RGB48BE, AV_PIX_FMT_RGBA64BE,
AV_PIX_FMT_PAL8,
AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY8A,
AV_PIX_FMT_GRAY16BE,
AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE
},
.priv_class = &pngenc_class,
};
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