Avoid integer overflows in the base64 handing functions

glib2-CVE-2008-4316.patch

@@ -0,0 +1,62 @@
+--- glib/gbase64.c.orig	2008-12-04 12:07:21.000000000 +0100
++++ glib/gbase64.c	2009-01-12 14:08:31.000000000 +0100
+@@ -54,8 +54,9 @@ static const char base64_alphabet[] =
+  *
+  * The output buffer must be large enough to fit all the data that will
+  * be written to it. Due to the way base64 encodes you will need
+- * at least: @len * 4 / 3 + 6 bytes. If you enable line-breaking you will
+- * need at least: @len * 4 / 3 + @len * 4 / (3 * 72) + 7 bytes.
++ * at least: (@len / 3 + 1) * 4 + 4 bytes (+ 4 may be needed in case of
++ * non-zero state). If you enable line-breaking you will need at least:
++ * ((@len / 3 + 1) * 4 + 4) / 72 + 1 bytes of extra space.
+  *
+  * @break_lines is typically used when putting base64-encoded data in emails.
+  * It breaks the lines at 72 columns instead of putting all of the text on 
+@@ -233,8 +234,14 @@ g_base64_encode (const guchar *data, 
+   g_return_val_if_fail (data != NULL, NULL);
+   g_return_val_if_fail (len > 0, NULL);
+ 
+-  /* We can use a smaller limit here, since we know the saved state is 0 */
+-  out = g_malloc (len * 4 / 3 + 4);
++  /* We can use a smaller limit here, since we know the saved state is 0,
++     +1 is needed for trailing \0, also check for unlikely integer overflow */
++  if (len >= ((G_MAXSIZE - 1) / 4 - 1) * 3)
++    g_error("%s: input too large for Base64 encoding (%"G_GSIZE_FORMAT" chars)",
++        G_STRLOC, len);
++
++  out = g_malloc ((len / 3 + 1) * 4 + 1);
++
+   outlen = g_base64_encode_step (data, len, FALSE, out, &state, &save);
+   outlen += g_base64_encode_close (FALSE, out + outlen, &state, &save);
+   out[outlen] = '\0';
+@@ -275,7 +282,8 @@ static const unsigned char mime_base64_r
+  *
+  * The output buffer must be large enough to fit all the data that will
+  * be written to it. Since base64 encodes 3 bytes in 4 chars you need
+- * at least: @len * 3 / 4 bytes.
++ * at least: (@len / 4) * 3 + 3 bytes (+ 3 may be needed in case of non-zero
++ * state).
+  * 
+  * Return value: The number of bytes of output that was written
+  *
+@@ -358,7 +366,8 @@ g_base64_decode (const gchar *text,
+ 		 gsize       *out_len)
+ {
+   guchar *ret;
+-  gint input_length, state = 0;
++  gsize input_length;
++  gint state = 0;
+   guint save = 0;
+   
+   g_return_val_if_fail (text != NULL, NULL);
+@@ -368,7 +377,9 @@ g_base64_decode (const gchar *text,
+ 
+   g_return_val_if_fail (input_length > 1, NULL);
+ 
+-  ret = g_malloc0 (input_length * 3 / 4);
++  /* We can use a smaller limit here, since we know the saved state is 0,
++     +1 used to avoid calling g_malloc0(0), and hence retruning NULL */
++  ret = g_malloc0 ((input_length / 4) * 3 + 1);
+   
+   *out_len = g_base64_decode_step (text, input_length, ret, &state, &save);
+   

glib2.spec

@@ -3,7 +3,7 @@
 Summary: A library of handy utility functions
 Name: glib2
 Version: 2.19.10
-Release: 1%{?dist}
+Release: 2%{?dist}
 License: LGPLv2+
 Group: System Environment/Libraries
 URL: http://www.gtk.org
@@ -22,6 +22,8 @@ BuildRequires: glibc-devel
 # this patch requires autoreconf
 BuildRequires: autoconf automake libtool gettext-devel gtk-doc
 
+Patch0: glib2-CVE-2008-4316.patch
+
 %description
 GLib is the low-level core library that forms the basis
 for projects such as GTK+ and GNOME. It provides data structure
@@ -53,6 +55,7 @@ of version 2 of the GLib library.
 
 %prep
 %setup -q -n glib-%{version}
+%patch0 -p1 -b .CVE-2008-4316
 
 libtoolize --force --copy
 autoreconf
@@ -123,6 +126,9 @@ rm -rf $RPM_BUILD_ROOT
 %{_libdir}/lib*.a
 
 %changelog
+* Thu Mar 12 2009 Matthias Clasen <mclasen@redhat.com> - 2.19.10-2
+- Fix integer overflows in the base64 handling functions. CVE-2008-4316
+
 * Mon Mar  2 2009 Matthias Clasen <mclasen@redhat.com> - 2.19.10-1
 - Update to 2.19.10