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dsicinvideo: validate buffer offset before copying pixels. 

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable-LOOeJiBropLYtjvyW6yDsg@public.gmane.org

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Ronald S. Bultje 2012-02-29 15:07:09 -08:00 committed by Michael Niedermayer
parent 2b693546ad
commit 999d38f3a9
1 changed files with 23 additions and 15 deletions
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38
libavcodec/dsicinav.c
View File

@ -147,11 +147,11 @@ static int cin_decode_huffman(const unsigned char *src, int src_size, unsigned c
return dst_cur - dst;
}
static void cin_decode_lzss(const unsigned char *src, int src_size, unsigned char *dst, int dst_size)
static int cin_decode_lzss(const unsigned char *src, int src_size, unsigned char *dst, int dst_size)
{
uint16_t cmd;
int i, sz, offset, code;
unsigned char *dst_end = dst + dst_size;
unsigned char *dst_end = dst + dst_size, *dst_start = dst;
const unsigned char *src_end = src + src_size;
while (src < src_end && dst < dst_end) {
@ -162,6 +162,8 @@ static void cin_decode_lzss(const unsigned char *src, int src_size, unsigned cha
} else {
cmd = AV_RL16(src); src += 2;
offset = cmd >> 4;
if ((int) (dst - dst_start) < offset + 1)
return AVERROR_INVALIDDATA;
sz = (cmd & 0xF) + 2;
/* don't use memcpy/memmove here as the decoding routine (ab)uses */
/* buffer overlappings to repeat bytes in the destination */
@ -202,13 +204,7 @@ static int cinvideo_decode_frame(AVCodecContext *avctx,
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
CinVideoContext *cin = avctx->priv_data;
int i, y, palette_type, palette_colors_count, bitmap_frame_type, bitmap_frame_size;
cin->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
if (avctx->reget_buffer(avctx, &cin->frame)) {
av_log(cin->avctx, AV_LOG_ERROR, "delphinecinvideo: reget_buffer() failed to allocate a frame\n");
return -1;
}
int i, y, palette_type, palette_colors_count, bitmap_frame_type, bitmap_frame_size, res = 0;
palette_type = buf[0];
palette_colors_count = AV_RL16(buf+1);
@ -234,8 +230,6 @@ static int cinvideo_decode_frame(AVCodecContext *avctx,
bitmap_frame_size -= 4;
}
}
memcpy(cin->frame.data[1], cin->palette, sizeof(cin->palette));
cin->frame.palette_has_changed = 1;
/* note: the decoding routines below assumes that surface.width = surface.pitch */
switch (bitmap_frame_type) {
@ -268,17 +262,31 @@ static int cinvideo_decode_frame(AVCodecContext *avctx,
cin->bitmap_table[CIN_CUR_BMP], cin->bitmap_size);
break;
case 38:
cin_decode_lzss(buf, bitmap_frame_size,
cin->bitmap_table[CIN_CUR_BMP], cin->bitmap_size);
res = cin_decode_lzss(buf, bitmap_frame_size,
cin->bitmap_table[CIN_CUR_BMP],
cin->bitmap_size);
if (res < 0)
return res;
break;
case 39:
cin_decode_lzss(buf, bitmap_frame_size,
cin->bitmap_table[CIN_CUR_BMP], cin->bitmap_size);
res = cin_decode_lzss(buf, bitmap_frame_size,
cin->bitmap_table[CIN_CUR_BMP],
cin->bitmap_size);
if (res < 0)
return res;
cin_apply_delta_data(cin->bitmap_table[CIN_PRE_BMP],
cin->bitmap_table[CIN_CUR_BMP], cin->bitmap_size);
break;
}
cin->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
if (avctx->reget_buffer(avctx, &cin->frame)) {
av_log(cin->avctx, AV_LOG_ERROR, "delphinecinvideo: reget_buffer() failed to allocate a frame\n");
return -1;
}
memcpy(cin->frame.data[1], cin->palette, sizeof(cin->palette));
cin->frame.palette_has_changed = 1;
for (y = 0; y < cin->avctx->height; ++y)
memcpy(cin->frame.data[0] + (cin->avctx->height - 1 - y) * cin->frame.linesize[0],
cin->bitmap_table[CIN_CUR_BMP] + y * cin->avctx->width,