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sgidec: fix buffer size check in expand_rle_row() 

Right now it will spuriously fail if the linesize is exactly equal to
the data width.

CC:libav-stable@libav.org
This commit is contained in:
Anton Khirnov 2014-01-02 09:34:20 +01:00
parent adb199d1bc
commit f4a8a00805
1 changed files with 18 additions and 4 deletions
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22
libavcodec/sgidec.c
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@ -26,6 +26,7 @@
#include "sgi.h" #include "sgi.h"
typedef struct SgiState { typedef struct SgiState {
AVCodecContext *avctx;
unsigned int width; unsigned int width;
unsigned int height; unsigned int height;
unsigned int depth; unsigned int depth;
@ -38,12 +39,12 @@ typedef struct SgiState {
* Expand an RLE row into a channel. * Expand an RLE row into a channel.
* @param s the current image state * @param s the current image state
* @param out_buf Points to one line after the output buffer. * @param out_buf Points to one line after the output buffer.
* @param out_end end of line in output buffer * @param len length of out_buf in bytes
* @param pixelstride pixel stride of input buffer * @param pixelstride pixel stride of input buffer
* @return size of output in bytes, -1 if buffer overflows * @return size of output in bytes, -1 if buffer overflows
*/ */
static int expand_rle_row(SgiState *s, uint8_t *out_buf, static int expand_rle_row(SgiState *s, uint8_t *out_buf,
uint8_t *out_end, int pixelstride) int len, int pixelstride)
{ {
unsigned char pixel, count; unsigned char pixel, count;
unsigned char *orig = out_buf; unsigned char *orig = out_buf;
@ -57,7 +58,10 @@ static int expand_rle_row(SgiState *s, uint8_t *out_buf,
} }
/* Check for buffer overflow. */ /* Check for buffer overflow. */
if(out_buf + pixelstride * count >= out_end) return -1; if (pixelstride * (count - 1) >= len) {
av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n");
return AVERROR_INVALIDDATA;
}
if (pixel & 0x80) { if (pixel & 0x80) {
while (count--) { while (count--) {
@ -100,7 +104,7 @@ static int read_rle_sgi(uint8_t *out_buf, SgiState *s)
dest_row -= s->linesize; dest_row -= s->linesize;
start_offset = bytestream2_get_be32(&g_table); start_offset = bytestream2_get_be32(&g_table);
bytestream2_seek(&s->g, start_offset, SEEK_SET); bytestream2_seek(&s->g, start_offset, SEEK_SET);
if (expand_rle_row(s, dest_row + z, dest_row + FFABS(s->linesize), if (expand_rle_row(s, dest_row + z, FFABS(s->linesize) - z,
s->depth) != s->width) { s->depth) != s->width) {
return AVERROR_INVALIDDATA; return AVERROR_INVALIDDATA;
} }
@ -233,6 +237,15 @@ static int decode_frame(AVCodecContext *avctx,
} }
} }
static av_cold int sgi_decode_init(AVCodecContext *avctx)
{
SgiState *s = avctx->priv_data;
s->avctx = avctx;
return 0;
}
AVCodec ff_sgi_decoder = { AVCodec ff_sgi_decoder = {
.name = "sgi", .name = "sgi",
.long_name = NULL_IF_CONFIG_SMALL("SGI image"), .long_name = NULL_IF_CONFIG_SMALL("SGI image"),
@ -240,5 +253,6 @@ AVCodec ff_sgi_decoder = {
.id = AV_CODEC_ID_SGI, .id = AV_CODEC_ID_SGI,
.priv_data_size = sizeof(SgiState), .priv_data_size = sizeof(SgiState),
.decode = decode_frame, .decode = decode_frame,
.init = sgi_decode_init,
.capabilities = CODEC_CAP_DR1, .capabilities = CODEC_CAP_DR1,
}; };