Fix some buffer overreads.
Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: [email protected]
---
libavcodec/vmnc.c | 105 ++++++++++++++++++++++++++----------------------------
1 file changed, 50 insertions(+), 55 deletions(-)
diff --git a/libavcodec/vmnc.c b/libavcodec/vmnc.c
index 0ea4fcb..d7b03a2 100644
--- a/libavcodec/vmnc.c
+++ b/libavcodec/vmnc.c
@@ -32,6 +32,7 @@
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "internal.h"
+#include "bytestream.h"
enum EncTypes {
MAGIC_WMVd = 0x574D5664,
@@ -63,6 +64,7 @@ typedef struct VmncContext {
int bigendian;
uint8_t pal[768];
int width, height;
+ GetByteContext gb;
/* cursor data */
int cur_w, cur_h;
@@ -73,20 +75,20 @@ typedef struct VmncContext {
} VmncContext;
/* read pixel value from stream */
-static av_always_inline int vmnc_get_pixel(const uint8_t* buf, int bpp, int be)
+static av_always_inline int vmnc_get_pixel(GetByteContext *gb, int bpp, int be)
{
switch (bpp * 2 + be) {
case 2:
- case 3: return *buf;
- case 4: return AV_RL16(buf);
- case 5: return AV_RB16(buf);
- case 8: return AV_RL32(buf);
- case 9: return AV_RB32(buf);
+ case 3: return bytestream2_get_byte(gb);
+ case 4: return bytestream2_get_le16(gb);
+ case 5: return bytestream2_get_be16(gb);
+ case 8: return bytestream2_get_le32(gb);
+ case 9: return bytestream2_get_be32(gb);
default: return 0;
}
}
-static void load_cursor(VmncContext *c, const uint8_t *src)
+static void load_cursor(VmncContext *c)
{
int i, j, p;
const int bpp = c->bpp2;
@@ -96,8 +98,7 @@ static void load_cursor(VmncContext *c, const uint8_t *src)
for (j = 0; j < c->cur_h; j++) {
for (i = 0; i < c->cur_w; i++) {
- p = vmnc_get_pixel(src, bpp, c->bigendian);
- src += bpp;
+ p = vmnc_get_pixel(&c->gb, bpp, c->bigendian);
if (bpp == 1) *dst8++ = p;
if (bpp == 2) *dst16++ = p;
if (bpp == 4) *dst32++ = p;
@@ -108,8 +109,7 @@ static void load_cursor(VmncContext *c, const uint8_t *src)
dst32 = (uint32_t*)c->curmask;
for (j = 0; j < c->cur_h; j++) {
for (i = 0; i < c->cur_w; i++) {
- p = vmnc_get_pixel(src, bpp, c->bigendian);
- src += bpp;
+ p = vmnc_get_pixel(&c->gb, bpp, c->bigendian);
if (bpp == 1) *dst8++ = p;
if (bpp == 2) *dst16++ = p;
if (bpp == 4) *dst32++ = p;
@@ -210,14 +210,13 @@ static av_always_inline void paint_rect(uint8_t *dst, int
dx, int dy,
}
static av_always_inline void paint_raw(uint8_t *dst, int w, int h,
- const uint8_t* src, int bpp,
+ GetByteContext *gb, int bpp,
int be, int stride)
{
int i, j, p;
for (j = 0; j < h; j++) {
for (i = 0; i < w; i++) {
- p = vmnc_get_pixel(src, bpp, be);
- src += bpp;
+ p = vmnc_get_pixel(gb, bpp, be);
switch (bpp) {
case 1:
dst[i] = p;
@@ -234,15 +233,14 @@ static av_always_inline void paint_raw(uint8_t *dst, int
w, int h,
}
}
-static int decode_hextile(VmncContext *c, uint8_t* dst, const uint8_t* src,
- int ssize, int w, int h, int stride)
+static int decode_hextile(VmncContext *c, uint8_t* dst, GetByteContext *gb,
+ int w, int h, int stride)
{
int i, j, k;
int bg = 0, fg = 0, rects, color, flags, xy, wh;
const int bpp = c->bpp2;
uint8_t *dst2;
int bw = 16, bh = 16;
- const uint8_t *ssrc=src;
for (j = 0; j < h; j += 16) {
dst2 = dst;
@@ -250,44 +248,43 @@ static int decode_hextile(VmncContext *c, uint8_t* dst,
const uint8_t* src,
if (j + 16 > h)
bh = h - j;
for (i = 0; i < w; i += 16, dst2 += 16 * bpp) {
- if (src - ssrc >= ssize) {
+ if (bytestream2_get_bytes_left(gb) <= 0) {
av_log(c->avctx, AV_LOG_ERROR, "Premature end of data!\n");
return -1;
}
if (i + 16 > w)
bw = w - i;
- flags = *src++;
+ flags = bytestream2_get_byte(gb);
if (flags & HT_RAW) {
- if (src - ssrc > ssize - bw * bh * bpp) {
+ if (bytestream2_get_bytes_left(gb) < bw * bh * bpp) {
av_log(c->avctx, AV_LOG_ERROR, "Premature end of data!\n");
return -1;
}
- paint_raw(dst2, bw, bh, src, bpp, c->bigendian, stride);
- src += bw * bh * bpp;
+ paint_raw(dst2, bw, bh, gb, bpp, c->bigendian, stride);
} else {
if (flags & HT_BKG) {
- bg = vmnc_get_pixel(src, bpp, c->bigendian); src += bpp;
+ bg = vmnc_get_pixel(gb, bpp, c->bigendian);
}
if (flags & HT_FG) {
- fg = vmnc_get_pixel(src, bpp, c->bigendian); src += bpp;
+ fg = vmnc_get_pixel(gb, bpp, c->bigendian);
}
rects = 0;
if (flags & HT_SUB)
- rects = *src++;
+ rects = bytestream2_get_byte(gb);
color = !!(flags & HT_CLR);
paint_rect(dst2, 0, 0, bw, bh, bg, bpp, stride);
- if (src - ssrc > ssize - rects * (color * bpp + 2)) {
+ if (bytestream2_get_bytes_left(gb) < rects * (color * bpp +
2)) {
av_log(c->avctx, AV_LOG_ERROR, "Premature end of data!\n");
return -1;
}
for (k = 0; k < rects; k++) {
if (color) {
- fg = vmnc_get_pixel(src, bpp, c->bigendian); src +=
bpp;
+ fg = vmnc_get_pixel(gb, bpp, c->bigendian);
}
- xy = *src++;
- wh = *src++;
+ xy = bytestream2_get_byte(gb);;
+ wh = bytestream2_get_byte(gb);;
paint_rect(dst2, xy >> 4, xy & 0xF,
(wh>>4)+1, (wh & 0xF)+1, fg, bpp, stride);
}
@@ -295,7 +292,7 @@ static int decode_hextile(VmncContext *c, uint8_t* dst,
const uint8_t* src,
}
dst += stride * 16;
}
- return src - ssrc;
+ return 0;
}
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
@@ -304,8 +301,8 @@ static int decode_frame(AVCodecContext *avctx, void *data,
int *got_frame,
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
VmncContext * const c = avctx->priv_data;
+ GetByteContext *gb = &c->gb;
uint8_t *outptr;
- const uint8_t *src = buf;
int dx, dy, w, h, depth, enc, chunks, res, size_left, ret;
if ((ret = ff_reget_buffer(avctx, &c->pic)) < 0) {
@@ -313,6 +310,8 @@ static int decode_frame(AVCodecContext *avctx, void *data,
int *got_frame,
return ret;
}
+ bytestream2_init(gb, buf, buf_size);
+
c->pic.key_frame = 0;
c->pic.pict_type = AV_PICTURE_TYPE_P;
@@ -344,16 +343,16 @@ static int decode_frame(AVCodecContext *avctx, void
*data, int *got_frame,
}
}
}
- src += 2;
- chunks = AV_RB16(src); src += 2;
+ bytestream2_skip(gb, 2);
+ chunks = bytestream2_get_be16(gb);
while (chunks--) {
- dx = AV_RB16(src); src += 2;
- dy = AV_RB16(src); src += 2;
- w = AV_RB16(src); src += 2;
- h = AV_RB16(src); src += 2;
- enc = AV_RB32(src); src += 4;
+ dx = bytestream2_get_be16(gb);
+ dy = bytestream2_get_be16(gb);
+ w = bytestream2_get_be16(gb);
+ h = bytestream2_get_be16(gb);
+ enc = bytestream2_get_be32(gb);
outptr = c->pic.data[0] + dx * c->bpp2 + dy * c->pic.linesize[0];
- size_left = buf_size - (src - buf);
+ size_left = bytestream2_get_bytes_left(gb);
switch (enc) {
case MAGIC_WMVd: // cursor
if (size_left < 2 + w * h * c->bpp2 * 2) {
@@ -362,7 +361,7 @@ static int decode_frame(AVCodecContext *avctx, void *data,
int *got_frame,
2 + w * h * c->bpp2 * 2, size_left);
return -1;
}
- src += 2;
+ bytestream2_skip(gb, 2);
c->cur_w = w;
c->cur_h = h;
c->cur_hx = dx;
@@ -377,44 +376,43 @@ static int decode_frame(AVCodecContext *avctx, void
*data, int *got_frame,
c->curbits = av_realloc(c->curbits, c->cur_w * c->cur_h * c->bpp2);
c->curmask = av_realloc(c->curmask, c->cur_w * c->cur_h * c->bpp2);
c->screendta = av_realloc(c->screendta, c->cur_w * c->cur_h *
c->bpp2);
- load_cursor(c, src);
- src += w * h * c->bpp2 * 2;
+ load_cursor(c);
break;
case MAGIC_WMVe: // unknown
- src += 2;
+ bytestream2_skip(gb, 2);
break;
case MAGIC_WMVf: // update cursor position
c->cur_x = dx - c->cur_hx;
c->cur_y = dy - c->cur_hy;
break;
case MAGIC_WMVg: // unknown
- src += 10;
+ bytestream2_skip(gb, 10);
break;
case MAGIC_WMVh: // unknown
- src += 4;
+ bytestream2_skip(gb, 4);
break;
case MAGIC_WMVi: // ServerInitialization struct
c->pic.key_frame = 1;
c->pic.pict_type = AV_PICTURE_TYPE_I;
- depth = *src++;
+ depth = bytestream2_get_byte(gb);
if (depth != c->bpp) {
av_log(avctx, AV_LOG_INFO,
"Depth mismatch. Container %i bpp, "
"Frame data: %i bpp\n",
c->bpp, depth);
}
- src++;
- c->bigendian = *src++;
+ bytestream2_skip(gb, 1);
+ c->bigendian = bytestream2_get_byte(gb);
if (c->bigendian & (~1)) {
av_log(avctx, AV_LOG_INFO,
"Invalid header: bigendian flag = %i\n", c->bigendian);
return -1;
}
//skip the rest of pixel format data
- src += 13;
+ bytestream2_skip(gb, 13);
break;
case MAGIC_WMVj: // unknown
- src += 2;
+ bytestream2_skip(gb, 2);
break;
case 0x00000000: // raw rectangle data
if ((dx + w > c->width) || (dy + h > c->height)) {
@@ -429,9 +427,8 @@ static int decode_frame(AVCodecContext *avctx, void *data,
int *got_frame,
w * h * c->bpp2, size_left);
return -1;
}
- paint_raw(outptr, w, h, src, c->bpp2, c->bigendian,
+ paint_raw(outptr, w, h, gb, c->bpp2, c->bigendian,
c->pic.linesize[0]);
- src += w * h * c->bpp2;
break;
case 0x00000005: // HexTile encoded rectangle
if ((dx + w > c->width) || (dy + h > c->height)) {
@@ -440,11 +437,9 @@ static int decode_frame(AVCodecContext *avctx, void *data,
int *got_frame,
w, h, dx, dy, c->width, c->height);
return -1;
}
- res = decode_hextile(c, outptr, src, size_left, w, h,
- c->pic.linesize[0]);
+ res = decode_hextile(c, outptr, gb, w, h, c->pic.linesize[0]);
if (res < 0)
return -1;
- src += res;
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unsupported block type 0x%08X\n",
enc);
--
1.8.3.2
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