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ffmpeg.wasm-core
Commit 61cd19b8 authored by Luca Barbato's avatar Luca Barbato
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vmnc: Port to bytestream2 

Fix some buffer overreads.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
parent a66aa0da
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Showing with 57 additions and 75 deletions
libavcodec/vmnc.c
View file @ 61cd19b8
......@@ -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;
......@@ -73,26 +75,25 @@ 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;
return bytestream2_get_byte(gb);
case 4:
return AV_RL16(buf);
return bytestream2_get_le16(gb);
case 5:
return AV_RB16(buf);
return bytestream2_get_be16(gb);
case 8:
return AV_RL32(buf);
return bytestream2_get_le32(gb);
case 9:
return AV_RB32(buf);
default:
return 0;
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;
......@@ -102,8 +103,7 @@ 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)
......@@ -117,8 +117,7 @@ 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)
......@@ -220,14 +219,13 @@ 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;
......@@ -244,15 +242,14 @@ 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;
......@@ -260,55 +257,48 @@ 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;
}
if (flags & HT_FG) {
fg = vmnc_get_pixel(src, bpp, c->bigendian);
src += bpp;
}
if (flags & HT_BKG)
bg = vmnc_get_pixel(gb, bpp, c->bigendian);
if (flags & HT_FG)
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;
}
xy = *src++;
wh = *src++;
paint_rect(dst2, xy >> 4, xy & 0xF, (wh >> 4) + 1,
(wh & 0xF) + 1, fg, bpp, stride);
if (color)
fg = vmnc_get_pixel(gb, bpp, c->bigendian);
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);
}
}
}
dst += stride * 16;
}
return src - ssrc;
return 0;
}
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
......@@ -317,8 +307,8 @@ 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) {
......@@ -326,6 +316,8 @@ 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;
......@@ -357,22 +349,16 @@ 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) {
......@@ -381,7 +367,7 @@ 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;
......@@ -396,44 +382,43 @@ 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;
//skip the rest of pixel format data
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)) {
......@@ -448,9 +433,8 @@ 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)) {
......@@ -459,11 +443,9 @@ 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);
......
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