145 lines
5.4 KiB
Diff
145 lines
5.4 KiB
Diff
Fix CVE-2016-9085 (several integer overflows):
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https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-9085
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http://seclists.org/oss-sec/2016/q4/253
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Patch copied from upstream source repository:
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https://chromium.googlesource.com/webm/libwebp/+/e2affacc35f1df6cc3b1a9fa0ceff5ce2d0cce83
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From e2affacc35f1df6cc3b1a9fa0ceff5ce2d0cce83 Mon Sep 17 00:00:00 2001
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From: Pascal Massimino <pascal.massimino@gmail.com>
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Date: Mon, 10 Oct 2016 11:48:39 +0200
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Subject: [PATCH] fix potential overflow when width * height * 4 >= (1<<32)
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Mostly: avoid doing calculation like: ptr + j * stride
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when stride is 'int'. Rather use size_t, or pointer increments (ptr += stride)
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when possible.
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BUG=webp:314
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Change-Id: I81c684b515dd1ec4f601f32d50a6e821c4e46e20
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---
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examples/gifdec.c | 56 +++++++++++++++++++++++++++++++------------------------
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1 file changed, 32 insertions(+), 24 deletions(-)
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diff --git a/examples/gifdec.c b/examples/gifdec.c
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index 83c3d82..7df176f 100644
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--- a/examples/gifdec.c
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+++ b/examples/gifdec.c
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@@ -20,6 +20,7 @@
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#include "webp/encode.h"
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#include "webp/mux_types.h"
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+#include "webp/format_constants.h"
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#define GIF_TRANSPARENT_COLOR 0x00000000
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#define GIF_WHITE_COLOR 0xffffffff
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@@ -103,12 +104,19 @@ int GIFReadFrame(GifFileType* const gif, int transparent_index,
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const GifImageDesc* const image_desc = &gif->Image;
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uint32_t* dst = NULL;
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uint8_t* tmp = NULL;
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- int ok = 0;
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- GIFFrameRect rect = {
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+ const GIFFrameRect rect = {
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image_desc->Left, image_desc->Top, image_desc->Width, image_desc->Height
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};
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+ const uint64_t memory_needed = 4 * rect.width * (uint64_t)rect.height;
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+ int ok = 0;
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*gif_rect = rect;
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+ if (memory_needed != (size_t)memory_needed ||
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+ memory_needed > 4 * MAX_IMAGE_AREA) {
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+ fprintf(stderr, "Image is too large (%d x %d).", rect.width, rect.height);
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+ return 0;
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+ }
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+
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// Use a view for the sub-picture:
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if (!WebPPictureView(picture, rect.x_offset, rect.y_offset,
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rect.width, rect.height, &sub_image)) {
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@@ -132,15 +140,15 @@ int GIFReadFrame(GifFileType* const gif, int transparent_index,
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y += interlace_jumps[pass]) {
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if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;
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Remap(gif, tmp, rect.width, transparent_index,
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- dst + y * sub_image.argb_stride);
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+ dst + y * (size_t)sub_image.argb_stride);
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}
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}
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} else { // Non-interlaced image.
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int y;
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- for (y = 0; y < rect.height; ++y) {
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+ uint32_t* ptr = dst;
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+ for (y = 0; y < rect.height; ++y, ptr += sub_image.argb_stride) {
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if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;
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- Remap(gif, tmp, rect.width, transparent_index,
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- dst + y * sub_image.argb_stride);
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+ Remap(gif, tmp, rect.width, transparent_index, ptr);
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}
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}
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ok = 1;
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@@ -216,13 +224,11 @@ int GIFReadMetadata(GifFileType* const gif, GifByteType** const buf,
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static void ClearRectangle(WebPPicture* const picture,
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int left, int top, int width, int height) {
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- int j;
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- for (j = top; j < top + height; ++j) {
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- uint32_t* const dst = picture->argb + j * picture->argb_stride;
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- int i;
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- for (i = left; i < left + width; ++i) {
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- dst[i] = GIF_TRANSPARENT_COLOR;
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- }
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+ int i, j;
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+ const size_t stride = picture->argb_stride;
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+ uint32_t* dst = picture->argb + top * stride + left;
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+ for (j = 0; j < height; ++j, dst += stride) {
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+ for (i = 0; i < width; ++i) dst[i] = GIF_TRANSPARENT_COLOR;
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}
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}
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@@ -246,29 +252,31 @@ void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,
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if (dispose == GIF_DISPOSE_BACKGROUND) {
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GIFClearPic(curr_canvas, rect);
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} else if (dispose == GIF_DISPOSE_RESTORE_PREVIOUS) {
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- const int src_stride = prev_canvas->argb_stride;
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- const uint32_t* const src =
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- prev_canvas->argb + rect->x_offset + rect->y_offset * src_stride;
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- const int dst_stride = curr_canvas->argb_stride;
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- uint32_t* const dst =
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- curr_canvas->argb + rect->x_offset + rect->y_offset * dst_stride;
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+ const size_t src_stride = prev_canvas->argb_stride;
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+ const uint32_t* const src = prev_canvas->argb + rect->x_offset
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+ + rect->y_offset * src_stride;
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+ const size_t dst_stride = curr_canvas->argb_stride;
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+ uint32_t* const dst = curr_canvas->argb + rect->x_offset
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+ + rect->y_offset * dst_stride;
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assert(prev_canvas != NULL);
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- WebPCopyPlane((uint8_t*)src, 4 * src_stride, (uint8_t*)dst, 4 * dst_stride,
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+ WebPCopyPlane((uint8_t*)src, (int)(4 * src_stride),
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+ (uint8_t*)dst, (int)(4 * dst_stride),
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4 * rect->width, rect->height);
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}
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}
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void GIFBlendFrames(const WebPPicture* const src,
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const GIFFrameRect* const rect, WebPPicture* const dst) {
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- int j;
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+ int i, j;
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+ const size_t src_stride = src->argb_stride;
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+ const size_t dst_stride = dst->argb_stride;
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assert(src->width == dst->width && src->height == dst->height);
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for (j = rect->y_offset; j < rect->y_offset + rect->height; ++j) {
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- int i;
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for (i = rect->x_offset; i < rect->x_offset + rect->width; ++i) {
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- const uint32_t src_pixel = src->argb[j * src->argb_stride + i];
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+ const uint32_t src_pixel = src->argb[j * src_stride + i];
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const int src_alpha = src_pixel >> 24;
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if (src_alpha != 0) {
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- dst->argb[j * dst->argb_stride + i] = src_pixel;
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+ dst->argb[j * dst_stride + i] = src_pixel;
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}
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}
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}
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--
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2.10.1
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