[FFmpeg-cvslog] kmvc: Use bytestream2 functions to prevent buffer overreads.
Laurentiu Ion
git at videolan.org
Wed Jan 11 02:57:10 CET 2012
ffmpeg | branch: master | Laurentiu Ion <ionlaurentiucristian at gmail.com> | Tue Jan 10 03:21:17 2012 +0200| [da2e774fd6841da7cede8c8ef30337449329727c] | committer: Ronald S. Bultje
kmvc: Use bytestream2 functions to prevent buffer overreads.
Signed-off-by: Ronald S. Bultje <rsbultje at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=da2e774fd6841da7cede8c8ef30337449329727c
---
libavcodec/kmvc.c | 150 ++++++++++++++++++++--------------------------------
1 files changed, 58 insertions(+), 92 deletions(-)
diff --git a/libavcodec/kmvc.c b/libavcodec/kmvc.c
index 6c55863..2b54b84 100644
--- a/libavcodec/kmvc.c
+++ b/libavcodec/kmvc.c
@@ -46,6 +46,7 @@ typedef struct KmvcContext {
uint32_t pal[256];
uint8_t *cur, *prev;
uint8_t *frm0, *frm1;
+ GetByteContext g;
} KmvcContext;
typedef struct BitBuf {
@@ -55,23 +56,19 @@ typedef struct BitBuf {
#define BLK(data, x, y) data[(x) + (y) * 320]
-#define kmvc_init_getbits(bb, src) bb.bits = 7; bb.bitbuf = *src++;
+#define kmvc_init_getbits(bb, g) bb.bits = 7; bb.bitbuf = bytestream2_get_byte(g);
-#define kmvc_getbit(bb, src, src_end, res) {\
+#define kmvc_getbit(bb, g, res) {\
res = 0; \
if (bb.bitbuf & (1 << bb.bits)) res = 1; \
bb.bits--; \
if(bb.bits == -1) { \
- if (src >= src_end) { \
- av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n"); \
- return AVERROR_INVALIDDATA; \
- } \
- bb.bitbuf = *src++; \
+ bb.bitbuf = bytestream2_get_byte(g); \
bb.bits = 7; \
} \
}
-static int kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int src_size, int w, int h)
+static int kmvc_decode_intra_8x8(KmvcContext * ctx, int w, int h)
{
BitBuf bb;
int res, val;
@@ -79,42 +76,33 @@ static int kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int src
int bx, by;
int l0x, l1x, l0y, l1y;
int mx, my;
- const uint8_t *src_end = src + src_size;
- kmvc_init_getbits(bb, src);
+ kmvc_init_getbits(bb, &ctx->g);
for (by = 0; by < h; by += 8)
for (bx = 0; bx < w; bx += 8) {
- kmvc_getbit(bb, src, src_end, res);
+ if (!bytestream2_get_bytes_left(&ctx->g)) {
+ av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
+ return AVERROR_INVALIDDATA;
+ }
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 8x8 block
- if (src >= src_end) {
- av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
- return AVERROR_INVALIDDATA;
- }
- val = *src++;
+ val = bytestream2_get_byte(&ctx->g);
for (i = 0; i < 64; i++)
BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
} else { // handle four 4x4 subblocks
for (i = 0; i < 4; i++) {
l0x = bx + (i & 1) * 4;
l0y = by + (i & 2) * 2;
- kmvc_getbit(bb, src, src_end, res);
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) {
- kmvc_getbit(bb, src, src_end, res);
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 4x4 block
- if (src >= src_end) {
- av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
- return AVERROR_INVALIDDATA;
- }
- val = *src++;
+ val = bytestream2_get_byte(&ctx->g);
for (j = 0; j < 16; j++)
BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
} else { // copy block from already decoded place
- if (src >= src_end) {
- av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
- return AVERROR_INVALIDDATA;
- }
- val = *src++;
+ val = bytestream2_get_byte(&ctx->g);
mx = val & 0xF;
my = val >> 4;
for (j = 0; j < 16; j++)
@@ -125,25 +113,17 @@ static int kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int src
for (j = 0; j < 4; j++) {
l1x = l0x + (j & 1) * 2;
l1y = l0y + (j & 2);
- kmvc_getbit(bb, src, src_end, res);
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) {
- kmvc_getbit(bb, src, src_end, res);
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 2x2 block
- if (src >= src_end) {
- av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
- return AVERROR_INVALIDDATA;
- }
- val = *src++;
+ val = bytestream2_get_byte(&ctx->g);
BLK(ctx->cur, l1x, l1y) = val;
BLK(ctx->cur, l1x + 1, l1y) = val;
BLK(ctx->cur, l1x, l1y + 1) = val;
BLK(ctx->cur, l1x + 1, l1y + 1) = val;
} else { // copy block from already decoded place
- if (src >= src_end) {
- av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
- return AVERROR_INVALIDDATA;
- }
- val = *src++;
+ val = bytestream2_get_byte(&ctx->g);
mx = val & 0xF;
my = val >> 4;
BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my);
@@ -155,10 +135,10 @@ static int kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int src
BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my);
}
} else { // read values for block
- BLK(ctx->cur, l1x, l1y) = *src++;
- BLK(ctx->cur, l1x + 1, l1y) = *src++;
- BLK(ctx->cur, l1x, l1y + 1) = *src++;
- BLK(ctx->cur, l1x + 1, l1y + 1) = *src++;
+ BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
+ BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
+ BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
+ BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
}
}
}
@@ -169,7 +149,7 @@ static int kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int src
return 0;
}
-static int kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int src_size, int w, int h)
+static int kmvc_decode_inter_8x8(KmvcContext * ctx, int w, int h)
{
BitBuf bb;
int res, val;
@@ -177,21 +157,20 @@ static int kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int src
int bx, by;
int l0x, l1x, l0y, l1y;
int mx, my;
- const uint8_t *src_end = src + src_size;
- kmvc_init_getbits(bb, src);
+ kmvc_init_getbits(bb, &ctx->g);
for (by = 0; by < h; by += 8)
for (bx = 0; bx < w; bx += 8) {
- kmvc_getbit(bb, src, src_end, res);
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) {
- kmvc_getbit(bb, src, src_end, res);
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 8x8 block
- if (src >= src_end) {
+ if (!bytestream2_get_bytes_left(&ctx->g)) {
av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
return AVERROR_INVALIDDATA;
}
- val = *src++;
+ val = bytestream2_get_byte(&ctx->g);
for (i = 0; i < 64; i++)
BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
} else { // copy block from previous frame
@@ -200,26 +179,22 @@ static int kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int src
BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3));
}
} else { // handle four 4x4 subblocks
+ if (!bytestream2_get_bytes_left(&ctx->g)) {
+ av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
+ return AVERROR_INVALIDDATA;
+ }
for (i = 0; i < 4; i++) {
l0x = bx + (i & 1) * 4;
l0y = by + (i & 2) * 2;
- kmvc_getbit(bb, src, src_end, res);
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) {
- kmvc_getbit(bb, src, src_end, res);
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 4x4 block
- if (src >= src_end) {
- av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
- return AVERROR_INVALIDDATA;
- }
- val = *src++;
+ val = bytestream2_get_byte(&ctx->g);
for (j = 0; j < 16; j++)
BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
} else { // copy block
- if (src >= src_end) {
- av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
- return AVERROR_INVALIDDATA;
- }
- val = *src++;
+ val = bytestream2_get_byte(&ctx->g);
mx = (val & 0xF) - 8;
my = (val >> 4) - 8;
for (j = 0; j < 16; j++)
@@ -230,25 +205,17 @@ static int kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int src
for (j = 0; j < 4; j++) {
l1x = l0x + (j & 1) * 2;
l1y = l0y + (j & 2);
- kmvc_getbit(bb, src, src_end, res);
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) {
- kmvc_getbit(bb, src, src_end, res);
+ kmvc_getbit(bb, &ctx->g, res);
if (!res) { // fill whole 2x2 block
- if (src >= src_end) {
- av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
- return AVERROR_INVALIDDATA;
- }
- val = *src++;
+ val = bytestream2_get_byte(&ctx->g);
BLK(ctx->cur, l1x, l1y) = val;
BLK(ctx->cur, l1x + 1, l1y) = val;
BLK(ctx->cur, l1x, l1y + 1) = val;
BLK(ctx->cur, l1x + 1, l1y + 1) = val;
} else { // copy block
- if (src >= src_end) {
- av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
- return AVERROR_INVALIDDATA;
- }
- val = *src++;
+ val = bytestream2_get_byte(&ctx->g);
mx = (val & 0xF) - 8;
my = (val >> 4) - 8;
BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my);
@@ -260,10 +227,10 @@ static int kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int src
BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my);
}
} else { // read values for block
- BLK(ctx->cur, l1x, l1y) = *src++;
- BLK(ctx->cur, l1x + 1, l1y) = *src++;
- BLK(ctx->cur, l1x, l1y + 1) = *src++;
- BLK(ctx->cur, l1x + 1, l1y + 1) = *src++;
+ BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
+ BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
+ BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
+ BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
}
}
}
@@ -276,8 +243,6 @@ static int kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int src
static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPacket *avpkt)
{
- const uint8_t *buf = avpkt->data;
- int buf_size = avpkt->size;
KmvcContext *const ctx = avctx->priv_data;
uint8_t *out, *src;
int i;
@@ -285,6 +250,7 @@ static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPa
int blocksize;
const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
+ bytestream2_init(&ctx->g, avpkt->data, avpkt->size);
if (ctx->pic.data[0])
avctx->release_buffer(avctx, &ctx->pic);
@@ -295,16 +261,16 @@ static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPa
return -1;
}
- header = *buf++;
+ header = bytestream2_get_byte(&ctx->g);
/* blocksize 127 is really palette change event */
- if (buf[0] == 127) {
- buf += 3;
+ if (bytestream2_peek_byte(&ctx->g) == 127) {
+ bytestream2_skip(&ctx->g, 3);
for (i = 0; i < 127; i++) {
- ctx->pal[i + (header & 0x81)] = AV_RB24(buf);
- buf += 4;
+ ctx->pal[i + (header & 0x81)] = bytestream2_get_be24(&ctx->g);
+ bytestream2_skip(&ctx->g, 1);
}
- buf -= 127 * 4 + 3;
+ bytestream2_seek(&ctx->g, -127 * 4 - 3, SEEK_CUR);
}
if (header & KMVC_KEYFRAME) {
@@ -319,7 +285,7 @@ static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPa
ctx->pic.palette_has_changed = 1;
// palette starts from index 1 and has 127 entries
for (i = 1; i <= ctx->palsize; i++) {
- ctx->pal[i] = bytestream_get_be24(&buf);
+ ctx->pal[i] = bytestream2_get_be24(&ctx->g);
}
}
@@ -336,7 +302,7 @@ static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPa
/* make the palette available on the way out */
memcpy(ctx->pic.data[1], ctx->pal, 1024);
- blocksize = *buf++;
+ blocksize = bytestream2_get_byte(&ctx->g);
if (blocksize != 8 && blocksize != 127) {
av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize);
@@ -349,10 +315,10 @@ static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPa
memcpy(ctx->cur, ctx->prev, 320 * 200);
break;
case 3:
- kmvc_decode_intra_8x8(ctx, buf, buf_size, avctx->width, avctx->height);
+ kmvc_decode_intra_8x8(ctx, avctx->width, avctx->height);
break;
case 4:
- kmvc_decode_inter_8x8(ctx, buf, buf_size, avctx->width, avctx->height);
+ kmvc_decode_inter_8x8(ctx, avctx->width, avctx->height);
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD);
@@ -380,7 +346,7 @@ static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPa
*(AVFrame *) data = ctx->pic;
/* always report that the buffer was completely consumed */
- return buf_size;
+ return avpkt->size;
}
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