[FFmpeg-cvslog] kvmc: fix invalid reads
Gaurav Narula
git at videolan.org
Mon Apr 2 01:45:32 CEST 2012
ffmpeg | branch: release/0.8 | Gaurav Narula <gnarula94 at gmail.com> | Mon Dec 12 20:42:54 2011 +0530| [24eabc53bae467cfe57e2c24dee0f33e11e697a1] | committer: Reinhard Tartler
kvmc: fix invalid reads
Signed-off-by: Janne Grunau <janne-libav at jannau.net>
(cherry picked from commit ad3161ec1d70291efcf40121d703ef73c0b08e5b)
Signed-off-by: Reinhard Tartler <siretart at tauware.de>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=24eabc53bae467cfe57e2c24dee0f33e11e697a1
---
libavcodec/kmvc.c | 82 ++++++++++++++++++++++++++++++++++++++++++----------
1 files changed, 66 insertions(+), 16 deletions(-)
diff --git a/libavcodec/kmvc.c b/libavcodec/kmvc.c
index 718cdfd..033d3d7 100644
--- a/libavcodec/kmvc.c
+++ b/libavcodec/kmvc.c
@@ -57,17 +57,21 @@ typedef struct BitBuf {
#define kmvc_init_getbits(bb, src) bb.bits = 7; bb.bitbuf = *src++;
-#define kmvc_getbit(bb, src, res) {\
+#define kmvc_getbit(bb, src, src_end, 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.bits = 7; \
} \
}
-static void kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int w, int h)
+static int kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int src_size, int w, int h)
{
BitBuf bb;
int res, val;
@@ -75,13 +79,18 @@ static void kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int w,
int bx, by;
int l0x, l1x, l0y, l1y;
int mx, my;
+ const uint8_t *src_end = src + src_size;
kmvc_init_getbits(bb, src);
for (by = 0; by < h; by += 8)
for (bx = 0; bx < w; bx += 8) {
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, 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++;
for (i = 0; i < 64; i++)
BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
@@ -89,14 +98,22 @@ static void kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int w,
for (i = 0; i < 4; i++) {
l0x = bx + (i & 1) * 4;
l0y = by + (i & 2) * 2;
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, res);
if (!res) {
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, 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++;
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++;
mx = val & 0xF;
my = val >> 4;
@@ -108,16 +125,24 @@ static void kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int w,
for (j = 0; j < 4; j++) {
l1x = l0x + (j & 1) * 2;
l1y = l0y + (j & 2);
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, res);
if (!res) {
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, 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++;
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++;
mx = val & 0xF;
my = val >> 4;
@@ -140,9 +165,11 @@ static void kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int w,
}
}
}
+
+ return 0;
}
-static void kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int w, int h)
+static int kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int src_size, int w, int h)
{
BitBuf bb;
int res, val;
@@ -150,15 +177,20 @@ static void kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int w,
int bx, by;
int l0x, l1x, l0y, l1y;
int mx, my;
+ const uint8_t *src_end = src + src_size;
kmvc_init_getbits(bb, src);
for (by = 0; by < h; by += 8)
for (bx = 0; bx < w; bx += 8) {
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, res);
if (!res) {
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, 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++;
for (i = 0; i < 64; i++)
BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
@@ -171,14 +203,22 @@ static void kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int w,
for (i = 0; i < 4; i++) {
l0x = bx + (i & 1) * 4;
l0y = by + (i & 2) * 2;
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, res);
if (!res) {
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, 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++;
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++;
mx = (val & 0xF) - 8;
my = (val >> 4) - 8;
@@ -190,16 +230,24 @@ static void kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int w,
for (j = 0; j < 4; j++) {
l1x = l0x + (j & 1) * 2;
l1y = l0y + (j & 2);
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, res);
if (!res) {
- kmvc_getbit(bb, src, res);
+ kmvc_getbit(bb, src, src_end, 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++;
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++;
mx = (val & 0xF) - 8;
my = (val >> 4) - 8;
@@ -222,6 +270,8 @@ static void kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int w,
}
}
}
+
+ return 0;
}
static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPacket *avpkt)
@@ -299,10 +349,10 @@ 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, avctx->width, avctx->height);
+ kmvc_decode_intra_8x8(ctx, buf, buf_size, avctx->width, avctx->height);
break;
case 4:
- kmvc_decode_inter_8x8(ctx, buf, avctx->width, avctx->height);
+ kmvc_decode_inter_8x8(ctx, buf, buf_size, avctx->width, avctx->height);
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD);
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