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From c812d1c1935cccf096a60ad904e640fdc83bd41c Mon Sep 17 00:00:00 2001
From: Adrian Johnson <ajohnson@redneon.com>
Date: Thu, 20 Oct 2016 21:12:30 +1030
Subject: [PATCH] image: prevent invalid ptr access for > 4GB images
Image data is often accessed using:
image->data + y * image->stride
On 64-bit achitectures if the image data is > 4GB, this computation
will overflow since both y and stride are 32-bit types.
https://bugs.freedesktop.org/show_bug.cgi?id=98165
---
boilerplate/cairo-boilerplate.c | 4 +++-
src/cairo-image-compositor.c | 4 ++--
src/cairo-image-surface-private.h | 2 +-
src/cairo-mesh-pattern-rasterizer.c | 2 +-
src/cairo-png.c | 2 +-
src/cairo-script-surface.c | 3 ++-
6 files changed, 10 insertions(+), 7 deletions(-)
--- a/boilerplate/cairo-boilerplate.c
+++ b/boilerplate/cairo-boilerplate.c
@@ -42,6 +42,7 @@
#undef CAIRO_VERSION_H
#include "../cairo-version.h"
+#include <stddef.h>
#include <stdlib.h>
#include <ctype.h>
#include <assert.h>
@@ -976,7 +977,8 @@ cairo_surface_t *
cairo_boilerplate_image_surface_create_from_ppm_stream (FILE *file)
{
char format;
- int width, height, stride;
+ int width, height;
+ ptrdiff_t stride;
int x, y;
unsigned char *data;
cairo_surface_t *image = NULL;
--- a/src/cairo-image-compositor.c
+++ b/src/cairo-image-compositor.c
@@ -1575,7 +1575,7 @@ typedef struct _cairo_image_span_rendere
pixman_image_t *src, *mask;
union {
struct fill {
- int stride;
+ ptrdiff_t stride;
uint8_t *data;
uint32_t pixel;
} fill;
@@ -1594,7 +1594,7 @@ typedef struct _cairo_image_span_rendere
struct finish {
cairo_rectangle_int_t extents;
int src_x, src_y;
- int stride;
+ ptrdiff_t stride;
uint8_t *data;
} mask;
} u;
--- a/src/cairo-image-surface-private.h
+++ b/src/cairo-image-surface-private.h
@@ -71,7 +71,7 @@ struct _cairo_image_surface {
int width;
int height;
- int stride;
+ ptrdiff_t stride;
int depth;
unsigned owns_data : 1;
--- a/src/cairo-mesh-pattern-rasterizer.c
+++ b/src/cairo-mesh-pattern-rasterizer.c
@@ -470,7 +470,7 @@ draw_pixel (unsigned char *data, int wid
tg += tg >> 16;
tb += tb >> 16;
- *((uint32_t*) (data + y*stride + 4*x)) = ((ta << 16) & 0xff000000) |
+ *((uint32_t*) (data + y*(ptrdiff_t)stride + 4*x)) = ((ta << 16) & 0xff000000) |
((tr >> 8) & 0xff0000) | ((tg >> 16) & 0xff00) | (tb >> 24);
}
}
--- a/src/cairo-png.c
+++ b/src/cairo-png.c
@@ -671,7 +671,7 @@ read_png (struct png_read_closure_t *png
}
for (i = 0; i < png_height; i++)
- row_pointers[i] = &data[i * stride];
+ row_pointers[i] = &data[i * (ptrdiff_t)stride];
png_read_image (png, row_pointers);
png_read_end (png, info);
--- a/src/cairo-script-surface.c
+++ b/src/cairo-script-surface.c
@@ -1201,7 +1201,8 @@ static cairo_status_t
_write_image_surface (cairo_output_stream_t *output,
const cairo_image_surface_t *image)
{
- int stride, row, width;
+ int row, width;
+ ptrdiff_t stride;
uint8_t row_stack[CAIRO_STACK_BUFFER_SIZE];
uint8_t *rowdata;
uint8_t *data;
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