[gdk-pixbuf] gdk-pixbuf: Tighten rowstride overflow check

[Bastien Nocera <hadess src gnome org>]

commit bb5492e3360eec136525677072ca292ec94f7193
Author: Bastien Nocera <hadess hadess net>
Date:   Thu Jul 27 12:12:27 2017 +0100

    gdk-pixbuf: Tighten rowstride overflow check
    
    The rowstride is stored as an int, and is an int in the public API.
    Making it an unsigned int for those calculations would increase
    the limit, which would obviously cause problems when the calculated
    value ends up between G_MAXUINT and G_MAXINT in the positives.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=765094

 gdk-pixbuf/gdk-pixbuf.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gdk-pixbuf/gdk-pixbuf.c b/gdk-pixbuf/gdk-pixbuf.c
index fb146ba..2ee0b2a 100644
--- a/gdk-pixbuf/gdk-pixbuf.c
+++ b/gdk-pixbuf/gdk-pixbuf.c
@@ -445,7 +445,7 @@ gdk_pixbuf_new (GdkColorspace colorspace,
 {
        guchar *buf;
        unsigned int channels;
-       unsigned int rowstride;
+       int rowstride;
 
        g_return_val_if_fail (colorspace == GDK_COLORSPACE_RGB, NULL);
        g_return_val_if_fail (bits_per_sample == 8, NULL);
@@ -455,7 +455,7 @@ gdk_pixbuf_new (GdkColorspace colorspace,
        channels = has_alpha ? 4 : 3;
 
        /* Overflow? */
-       if (width > (G_MAXUINT - 3) / channels)
+       if (width > (G_MAXINT - 3) / channels)
                return NULL;
 
        /* Always align rows to 32-bit boundaries */