Thu Oct 10 01:58:46 PDT 2013

2 files changed, 96 insertions, 3 deletions

diff --git a/extra/xorg-server/0001-Avoid-use-after-free-in-dix-dixfonts.c-doImageText-C.patch b/extra/xorg-server/0001-Avoid-use-after-free-in-dix-dixfonts.c-doImageText-C.patch
new file mode 100644
index 000000000..b550bcedd
--- /dev/null
+++ b/extra/xorg-server/0001-Avoid-use-after-free-in-dix-dixfonts.c-doImageText-C.patch
@@ -0,0 +1,76 @@
+From 7bddc2ba16a2a15773c2ea8947059afa27727764 Mon Sep 17 00:00:00 2001
+From: Alan Coopersmith <alan.coopersmith@oracle.com>
+Date: Mon, 16 Sep 2013 21:47:16 -0700
+Subject: [PATCH] Avoid use-after-free in dix/dixfonts.c: doImageText()
+ [CVE-2013-4396]
+
+Save a pointer to the passed in closure structure before copying it
+and overwriting the *c pointer to point to our copy instead of the
+original.  If we hit an error, once we free(c), reset c to point to
+the original structure before jumping to the cleanup code that
+references *c.
+
+Since one of the errors being checked for is whether the server was
+able to malloc(c->nChars * itemSize), the client can potentially pass
+a number of characters chosen to cause the malloc to fail and the
+error path to be taken, resulting in the read from freed memory.
+
+Since the memory is accessed almost immediately afterwards, and the
+X server is mostly single threaded, the odds of the free memory having
+invalid contents are low with most malloc implementations when not using
+memory debugging features, but some allocators will definitely overwrite
+the memory there, leading to a likely crash.
+
+Reported-by: Pedro Ribeiro <pedrib@gmail.com>
+Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
+Reviewed-by: Julien Cristau <jcristau@debian.org>
+---
+ dix/dixfonts.c |    5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/dix/dixfonts.c b/dix/dixfonts.c
+index feb765d..2e34d37 100644
+--- a/dix/dixfonts.c
++++ b/dix/dixfonts.c
+@@ -1425,6 +1425,7 @@ doImageText(ClientPtr client, ITclosurePtr c)
+             GC *pGC;
+             unsigned char *data;
+             ITclosurePtr new_closure;
++            ITclosurePtr old_closure;
+ 
+             /* We're putting the client to sleep.  We need to
+                save some state.  Similar problem to that handled
+@@ -1436,12 +1437,14 @@ doImageText(ClientPtr client, ITclosurePtr c)
+                 err = BadAlloc;
+                 goto bail;
+             }
++            old_closure = c;
+             *new_closure = *c;
+             c = new_closure;
+ 
+             data = malloc(c->nChars * itemSize);
+             if (!data) {
+                 free(c);
++                c = old_closure;
+                 err = BadAlloc;
+                 goto bail;
+             }
+@@ -1452,6 +1455,7 @@ doImageText(ClientPtr client, ITclosurePtr c)
+             if (!pGC) {
+                 free(c->data);
+                 free(c);
++                c = old_closure;
+                 err = BadAlloc;
+                 goto bail;
+             }
+@@ -1464,6 +1468,7 @@ doImageText(ClientPtr client, ITclosurePtr c)
+                 FreeScratchGC(pGC);
+                 free(c->data);
+                 free(c);
++                c = old_closure;
+                 err = BadAlloc;
+                 goto bail;
+             }
+-- 
+1.7.9.2
+
diff --git a/extra/xorg-server/PKGBUILD b/extra/xorg-server/PKGBUILD
index e6e01ef2a..064578096 100644
--- a/extra/xorg-server/PKGBUILD
+++ b/extra/xorg-server/PKGBUILD
@@ -1,11 +1,11 @@
-# $Id: PKGBUILD 194374 2013-09-15 07:40:13Z andyrtr $
+# $Id: PKGBUILD 196227 2013-10-08 22:59:23Z lcarlier $
 # Maintainer: AndyRTR <andyrtr@archlinux.org>
 # Maintainer: Jan de Groot <jgc@archlinux.org>
 
 pkgbase=xorg-server
 pkgname=('xorg-server' 'xorg-server-xephyr' 'xorg-server-xdmx' 'xorg-server-xvfb' 'xorg-server-xnest' 'xorg-server-common' 'xorg-server-devel')
 pkgver=1.14.3
-pkgrel=1
+pkgrel=2
 arch=('i686' 'x86_64')
 license=('custom')
 url="http://xorg.freedesktop.org"
@@ -23,7 +23,8 @@ source=(${url}/releases/individual/xserver/${pkgbase}-${pkgver}.tar.bz2
         xvfb-run
         xvfb-run.1
         10-quirks.conf
-        fb-rename-wfbDestroyGlyphCache.patch)
+        fb-rename-wfbDestroyGlyphCache.patch
+	0001-Avoid-use-after-free-in-dix-dixfonts.c-doImageText-C.patch)
 sha256sums=('02125ae13a443dcbb55f964d5c37f1da2f58ad54c2102356037bec23c1b84f5e'
             '66e25f76a7496c429e0aff4b0670f168719bb0ceaeb88c6f2272f2bf3ed21162'
             'd027776fac1f7675b0a9ee817502290b1c45f9c09b0f0a6bb058c35f92361e84'
@@ -54,7 +55,12 @@ prepare() {
 
   # http://cgit.freedesktop.org/xorg/xserver/commit/fb/wfbrename.h?id=5047810a4c20fab444b8c6eb146c55dcdb0d4219
   patch -Np1 -i ../fb-rename-wfbDestroyGlyphCache.patch
+
+  # CVE-2013-4396: Use after free in Xserver handling of ImageText requests
+  # (to be included in xorg-server 1.15.0 and 1.14.4)
+  patch -Np1 -i ../0001-Avoid-use-after-free-in-dix-dixfonts.c-doImageText-C.patch
 }
+
 build() {
   cd "${pkgbase}-${pkgver}"
   autoreconf -fi
@@ -218,3 +224,14 @@ package_xorg-server-devel() {
   install -m755 -d "${pkgdir}/usr/share/licenses/xorg-server-devel"
   ln -sf ../xorg-server-common/COPYING "${pkgdir}/usr/share/licenses/xorg-server-devel/COPYING"
 }
+sha256sums=('02125ae13a443dcbb55f964d5c37f1da2f58ad54c2102356037bec23c1b84f5e'
+            '66e25f76a7496c429e0aff4b0670f168719bb0ceaeb88c6f2272f2bf3ed21162'
+            'd027776fac1f7675b0a9ee817502290b1c45f9c09b0f0a6bb058c35f92361e84'
+            'e033f9bcc21980f7f0428e6ed6c362a3d55ad293b05fd6e6c6c1933b86f9e63a'
+            '26ee6ff255a60d7c1e136c612925eb63c86e85a4a3a55d531852ad9275526588'
+            'bb63658d250c21bbfaf94c5417f2920ce5963ee1f7db6cac2b163a54f2e9b619'
+            'ff0156309470fc1d378fd2e104338020a884295e285972cc88e250e031cc35b9'
+            '2460adccd3362fefd4cdc5f1c70f332d7b578091fb9167bf88b5f91265bbd776'
+            '94612f5c0d34a3b7152915c2e285c7b462e9d8e38d3539bd551a339498eac166'
+            'd0832cc16b5e6c1dee2959055a4b327f5c87e2a67b5f427d654663057207b2c1'
+            '2b90ce92a900b6d4edda9ef33acdd3d2c2708fec2344175c2d8dfd4265f56d32')