gdk-pixbuf: add security patch for CVE-2015-4491

Fixes:
CVE-2015-4491 - Heap overflow in gdk-pixbuf when scaling bitmap images.
Patch from upstream:
https://git.gnome.org/browse/gdk-pixbuf/commit/?id=ffec86e

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gdk-pixbuf/0001-fix-CVE-2015-4491.patch

@@ -0,0 +1,84 @@
+From ffec86ed5010c5a2be14f47b33bcf4ed3169a199 Mon Sep 17 00:00:00 2001
+From: Matthias Clasen <mclasen@redhat.com>
+Date: Mon, 13 Jul 2015 00:33:40 -0400
+Subject: pixops: Be more careful about integer overflow
+
+Our loader code is supposed to handle out-of-memory and overflow
+situations gracefully, reporting errors instead of aborting. But
+if you load an image at a specific size, we also execute our
+scaling code, which was not careful enough about overflow in some
+places.
+
+This commit makes the scaling code silently return if it fails to
+allocate filter tables. This is the best we can do, since
+gdk_pixbuf_scale() is not taking a GError.
+
+https://bugzilla.gnome.org/show_bug.cgi?id=752297
+
+Signed-off-by: Gustavo Zacarisa <gustavo@zacarias.com.ar>
+
+diff --git a/gdk-pixbuf/pixops/pixops.c b/gdk-pixbuf/pixops/pixops.c
+index 29a1c14..ce51745 100644
+--- a/gdk-pixbuf/pixops/pixops.c
++++ b/gdk-pixbuf/pixops/pixops.c
+@@ -1272,7 +1272,16 @@ make_filter_table (PixopsFilter *filter)
+   int i_offset, j_offset;
+   int n_x = filter->x.n;
+   int n_y = filter->y.n;
+-  int *weights = g_new (int, SUBSAMPLE * SUBSAMPLE * n_x * n_y);
++  gsize n_weights;
++  int *weights;
++
++  n_weights = SUBSAMPLE * SUBSAMPLE * n_x * n_y;
++  if (n_weights / (SUBSAMPLE * SUBSAMPLE * n_x) != n_y)
++    return NULL; /* overflow, bail */
++
++  weights = g_try_new (int, n_weights);
++  if (!weights)
++    return NULL; /* overflow, bail */
+ 
+   for (i_offset=0; i_offset < SUBSAMPLE; i_offset++)
+     for (j_offset=0; j_offset < SUBSAMPLE; j_offset++)
+@@ -1347,8 +1356,11 @@ pixops_process (guchar         *dest_buf,
+   if (x_step == 0 || y_step == 0)
+     return; /* overflow, bail out */
+ 
+-  line_bufs = g_new (guchar *, filter->y.n);
+   filter_weights = make_filter_table (filter);
++  if (!filter_weights)
++    return; /* overflow, bail out */
++
++  line_bufs = g_new (guchar *, filter->y.n);
+ 
+   check_shift = check_size ? get_check_shift (check_size) : 0;
+ 
+@@ -1468,7 +1480,7 @@ tile_make_weights (PixopsFilterDimension *dim,
+ 		   double                 scale)
+ {
+   int n = ceil (1 / scale + 1);
+-  double *pixel_weights = g_new (double, SUBSAMPLE * n);
++  double *pixel_weights = g_malloc_n (sizeof (double) * SUBSAMPLE, n);
+   int offset;
+   int i;
+ 
+@@ -1526,7 +1538,7 @@ bilinear_magnify_make_weights (PixopsFilterDimension *dim,
+     }
+ 
+   dim->n = n;
+-  dim->weights = g_new (double, SUBSAMPLE * n);
++  dim->weights = g_malloc_n (sizeof (double) * SUBSAMPLE, n);
+ 
+   pixel_weights = dim->weights;
+ 
+@@ -1617,7 +1629,7 @@ bilinear_box_make_weights (PixopsFilterDimension *dim,
+ 			   double                 scale)
+ {
+   int n = ceil (1/scale + 3.0);
+-  double *pixel_weights = g_new (double, SUBSAMPLE * n);
++  double *pixel_weights = g_malloc_n (sizeof (double) * SUBSAMPLE, n);
+   double w;
+   int offset, i;
+ 
+-- 
+cgit v0.10.2
+