commit ffec86ed5010c5a2be14f47b33bcf4ed3169a199

Author: Matthias Clasen <mclasen@redhat.com>

Date:   Mon Jul 13 00:33:40 2015 -0400

    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

commit 8dba67cb4f38d62a47757741ad41e3f245b4a32a

Author: Benjamin Otte <otte@redhat.com>

Date:   Mon Aug 17 18:52:47 2015 +0200

    pixops: Fix oversight for CVE-2015-4491

    The n_x variable could be made large enough to overflow, too.

    Also included are various testcases for this vulnerability:

    - The original exploit (adapted for the testsuite)

    - Causing overflow by making both X and Y variables large

    - Causing overflow using only the X variable

    - Causing overflow using only the Y variable

    https://bugzilla.gnome.org/show_bug.cgi?id=752297

diff --git a/gdk-pixbuf/pixops/pixops.c b/gdk-pixbuf/pixops/pixops.c

index 29a1c14..7f2cbff 100644

--- a/gdk-pixbuf/pixops/pixops.c

+++ b/gdk-pixbuf/pixops/pixops.c

@@ -1272,7 +1272,20 @@ 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;

+  if (n_weights / (SUBSAMPLE * SUBSAMPLE) != n_x)

+    return NULL; /* overflow, bail */

+

+  n_weights *= 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 +1360,11 @@ 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 +1484,7 @@ 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 +1542,7 @@ 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 +1633,7 @@ 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;