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FFmpeg/libavcodec/xwddec.c
Andreas Cadhalpun 8431629dd1 xwddec: prevent overflow of lsize * avctx->height 
This is used to check if the input buffer is larger enough, so if this
overflows it can cause a false negative leading to a segmentation fault
in bytestream2_get_bufferu.

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
2016-01-13 09:39:13 +01:00

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/*
* XWD image format
*
* Copyright (c) 2012 Paul B Mahol
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <inttypes.h>
#include "libavutil/imgutils.h"
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
#include "xwd.h"
static int xwd_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame, AVPacket *avpkt)
{
AVFrame *p = data;
const uint8_t *buf = avpkt->data;
int i, ret, buf_size = avpkt->size;
uint32_t version, header_size, vclass, ncolors;
uint32_t xoffset, be, bpp, lsize, rsize;
uint32_t pixformat, pixdepth, bunit, bitorder, bpad;
uint32_t rgb[3];
uint8_t *ptr;
GetByteContext gb;
if (buf_size < XWD_HEADER_SIZE)
return AVERROR_INVALIDDATA;
bytestream2_init(&gb, buf, buf_size);
header_size = bytestream2_get_be32u(&gb);
version = bytestream2_get_be32u(&gb);
if (version != XWD_VERSION) {
av_log(avctx, AV_LOG_ERROR, "unsupported version\n");
return AVERROR_INVALIDDATA;
}
if (buf_size < header_size || header_size < XWD_HEADER_SIZE) {
av_log(avctx, AV_LOG_ERROR, "invalid header size\n");
return AVERROR_INVALIDDATA;
}
pixformat = bytestream2_get_be32u(&gb);
pixdepth = bytestream2_get_be32u(&gb);
avctx->width = bytestream2_get_be32u(&gb);
avctx->height = bytestream2_get_be32u(&gb);
xoffset = bytestream2_get_be32u(&gb);
be = bytestream2_get_be32u(&gb);
bunit = bytestream2_get_be32u(&gb);
bitorder = bytestream2_get_be32u(&gb);
bpad = bytestream2_get_be32u(&gb);
bpp = bytestream2_get_be32u(&gb);
lsize = bytestream2_get_be32u(&gb);
vclass = bytestream2_get_be32u(&gb);
rgb[0] = bytestream2_get_be32u(&gb);
rgb[1] = bytestream2_get_be32u(&gb);
rgb[2] = bytestream2_get_be32u(&gb);
bytestream2_skipu(&gb, 8);
ncolors = bytestream2_get_be32u(&gb);
bytestream2_skipu(&gb, header_size - (XWD_HEADER_SIZE - 20));
av_log(avctx, AV_LOG_DEBUG,
"pixformat %"PRIu32", pixdepth %"PRIu32", bunit %"PRIu32", bitorder %"PRIu32", bpad %"PRIu32"\n",
pixformat, pixdepth, bunit, bitorder, bpad);
av_log(avctx, AV_LOG_DEBUG,
"vclass %"PRIu32", ncolors %"PRIu32", bpp %"PRIu32", be %"PRIu32", lsize %"PRIu32", xoffset %"PRIu32"\n",
vclass, ncolors, bpp, be, lsize, xoffset);
av_log(avctx, AV_LOG_DEBUG,
"red %0"PRIx32", green %0"PRIx32", blue %0"PRIx32"\n",
rgb[0], rgb[1], rgb[2]);
if (pixformat > XWD_Z_PIXMAP) {
av_log(avctx, AV_LOG_ERROR, "invalid pixmap format\n");
return AVERROR_INVALIDDATA;
}
if (pixdepth == 0 || pixdepth > 32) {
av_log(avctx, AV_LOG_ERROR, "invalid pixmap depth\n");
return AVERROR_INVALIDDATA;
}
if (xoffset) {
avpriv_request_sample(avctx, "xoffset %"PRIu32"", xoffset);
return AVERROR_PATCHWELCOME;
}
if (be > 1) {
av_log(avctx, AV_LOG_ERROR, "invalid byte order\n");
return AVERROR_INVALIDDATA;
}
if (bitorder > 1) {
av_log(avctx, AV_LOG_ERROR, "invalid bitmap bit order\n");
return AVERROR_INVALIDDATA;
}
if (bunit != 8 && bunit != 16 && bunit != 32) {
av_log(avctx, AV_LOG_ERROR, "invalid bitmap unit\n");
return AVERROR_INVALIDDATA;
}
if (bpad != 8 && bpad != 16 && bpad != 32) {
av_log(avctx, AV_LOG_ERROR, "invalid bitmap scan-line pad\n");
return AVERROR_INVALIDDATA;
}
if (bpp == 0 || bpp > 32) {
av_log(avctx, AV_LOG_ERROR, "invalid bits per pixel\n");
return AVERROR_INVALIDDATA;
}
if (ncolors > 256) {
av_log(avctx, AV_LOG_ERROR, "invalid number of entries in colormap\n");
return AVERROR_INVALIDDATA;
}
if ((ret = av_image_check_size(avctx->width, avctx->height, 0, NULL)) < 0)
return ret;
rsize = FFALIGN(avctx->width * bpp, bpad) / 8;
if (lsize < rsize) {
av_log(avctx, AV_LOG_ERROR, "invalid bytes per scan-line\n");
return AVERROR_INVALIDDATA;
}
if (bytestream2_get_bytes_left(&gb) < ncolors * XWD_CMAP_SIZE + (uint64_t)avctx->height * lsize) {
av_log(avctx, AV_LOG_ERROR, "input buffer too small\n");
return AVERROR_INVALIDDATA;
}
if (pixformat != XWD_Z_PIXMAP) {
av_log(avctx, AV_LOG_ERROR, "pixmap format %"PRIu32" unsupported\n", pixformat);
return AVERROR_PATCHWELCOME;
}
avctx->pix_fmt = AV_PIX_FMT_NONE;
switch (vclass) {
case XWD_STATIC_GRAY:
case XWD_GRAY_SCALE:
if (bpp != 1)
return AVERROR_INVALIDDATA;
if (pixdepth == 1)
avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
break;
case XWD_STATIC_COLOR:
case XWD_PSEUDO_COLOR:
if (bpp == 8)
avctx->pix_fmt = AV_PIX_FMT_PAL8;
break;
case XWD_TRUE_COLOR:
case XWD_DIRECT_COLOR:
if (bpp != 16 && bpp != 24 && bpp != 32)
return AVERROR_INVALIDDATA;
if (bpp == 16 && pixdepth == 15) {
if (rgb[0] == 0x7C00 && rgb[1] == 0x3E0 && rgb[2] == 0x1F)
avctx->pix_fmt = be ? AV_PIX_FMT_RGB555BE : AV_PIX_FMT_RGB555LE;
else if (rgb[0] == 0x1F && rgb[1] == 0x3E0 && rgb[2] == 0x7C00)
avctx->pix_fmt = be ? AV_PIX_FMT_BGR555BE : AV_PIX_FMT_BGR555LE;
} else if (bpp == 16 && pixdepth == 16) {
if (rgb[0] == 0xF800 && rgb[1] == 0x7E0 && rgb[2] == 0x1F)
avctx->pix_fmt = be ? AV_PIX_FMT_RGB565BE : AV_PIX_FMT_RGB565LE;
else if (rgb[0] == 0x1F && rgb[1] == 0x7E0 && rgb[2] == 0xF800)
avctx->pix_fmt = be ? AV_PIX_FMT_BGR565BE : AV_PIX_FMT_BGR565LE;
} else if (bpp == 24) {
if (rgb[0] == 0xFF0000 && rgb[1] == 0xFF00 && rgb[2] == 0xFF)
avctx->pix_fmt = be ? AV_PIX_FMT_RGB24 : AV_PIX_FMT_BGR24;
else if (rgb[0] == 0xFF && rgb[1] == 0xFF00 && rgb[2] == 0xFF0000)
avctx->pix_fmt = be ? AV_PIX_FMT_BGR24 : AV_PIX_FMT_RGB24;
} else if (bpp == 32) {
if (rgb[0] == 0xFF0000 && rgb[1] == 0xFF00 && rgb[2] == 0xFF)
avctx->pix_fmt = be ? AV_PIX_FMT_ARGB : AV_PIX_FMT_BGRA;
else if (rgb[0] == 0xFF && rgb[1] == 0xFF00 && rgb[2] == 0xFF0000)
avctx->pix_fmt = be ? AV_PIX_FMT_ABGR : AV_PIX_FMT_RGBA;
}
bytestream2_skipu(&gb, ncolors * XWD_CMAP_SIZE);
break;
default:
av_log(avctx, AV_LOG_ERROR, "invalid visual class\n");
return AVERROR_INVALIDDATA;
}
if (avctx->pix_fmt == AV_PIX_FMT_NONE) {
avpriv_request_sample(avctx,
"Unknown file: bpp %"PRIu32", pixdepth %"PRIu32", vclass %"PRIu32"",
bpp, pixdepth, vclass);
return AVERROR_PATCHWELCOME;
}
if ((ret = ff_get_buffer(avctx, p, 0)) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return ret;
}
p->key_frame = 1;
p->pict_type = AV_PICTURE_TYPE_I;
if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {
uint32_t *dst = (uint32_t *)p->data[1];
uint8_t red, green, blue;
for (i = 0; i < ncolors; i++) {
bytestream2_skipu(&gb, 4); // skip colormap entry number
red = bytestream2_get_byteu(&gb);
bytestream2_skipu(&gb, 1);
green = bytestream2_get_byteu(&gb);
bytestream2_skipu(&gb, 1);
blue = bytestream2_get_byteu(&gb);
bytestream2_skipu(&gb, 3); // skip bitmask flag and padding
dst[i] = red << 16 | green << 8 | blue;
}
}
ptr = p->data[0];
for (i = 0; i < avctx->height; i++) {
bytestream2_get_bufferu(&gb, ptr, rsize);
bytestream2_skipu(&gb, lsize - rsize);
ptr += p->linesize[0];
}
*got_frame = 1;
return buf_size;
}
AVCodec ff_xwd_decoder = {
.name = "xwd",
.long_name = NULL_IF_CONFIG_SMALL("XWD (X Window Dump) image"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_XWD,
.decode = xwd_decode_frame,
.capabilities = AV_CODEC_CAP_DR1,
};
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