[bug#48001] [PATCH] gnu: xorg-server: CVE-2021-3472.

[Leo Famulari <leo@famulari.name>]

* gnu/packages/patches/xorg-server-CVE-2021-3472.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/xorg.scm (xorg-server)[source]: Use it.
---
 gnu/local.mk                                  |  1 +
 .../patches/xorg-server-CVE-2021-3472.patch   | 44 +++++++++++++++++++
 gnu/packages/xorg.scm                         |  5 ++-
 3 files changed, 48 insertions(+), 2 deletions(-)
 create mode 100644 gnu/packages/patches/xorg-server-CVE-2021-3472.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index 50b11a8ca2..3d076de924 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1815,6 +1815,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/xfce4-panel-plugins.patch		\
   %D%/packages/patches/xfce4-settings-defaults.patch		\
   %D%/packages/patches/xmonad-dynamic-linking.patch		\
+  %D%/packages/patches/xorg-server-CVE-2021-3472.patch		\
   %D%/packages/patches/xplanet-1.3.1-cxx11-eof.patch		\
   %D%/packages/patches/xplanet-1.3.1-libdisplay_DisplayOutput.cpp.patch	\
   %D%/packages/patches/xplanet-1.3.1-libimage_gif.c.patch	\
diff --git a/gnu/packages/patches/xorg-server-CVE-2021-3472.patch b/gnu/packages/patches/xorg-server-CVE-2021-3472.patch
new file mode 100644
index 0000000000..523a5b1dbf
--- /dev/null
+++ b/gnu/packages/patches/xorg-server-CVE-2021-3472.patch
@@ -0,0 +1,44 @@
+Fix CVE-2021-3472:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3472
+https://seclists.org/oss-sec/2021/q2/20
+
+Patch copied from upstream source repository:
+
+https://gitlab.freedesktop.org/xorg/xserver/-/commit/7aaf54a1884f71dc363f0b884e57bcb67407a6cd
+
+From 7aaf54a1884f71dc363f0b884e57bcb67407a6cd Mon Sep 17 00:00:00 2001
+From: Matthieu Herrb <matthieu@herrb.eu>
+Date: Sun, 21 Mar 2021 18:38:57 +0100
+Subject: [PATCH] Fix XChangeFeedbackControl() request underflow
+
+CVE-2021-3472 / ZDI-CAN-1259
+
+This vulnerability was discovered by:
+Jan-Niklas Sohn working with Trend Micro Zero Day Initiative
+
+Signed-off-by: Matthieu Herrb <matthieu@herrb.eu>
+---
+ Xi/chgfctl.c | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/Xi/chgfctl.c b/Xi/chgfctl.c
+index 1de4da9ef..7a597e43d 100644
+--- a/Xi/chgfctl.c
++++ b/Xi/chgfctl.c
+@@ -464,8 +464,11 @@ ProcXChangeFeedbackControl(ClientPtr client)
+         break;
+     case StringFeedbackClass:
+     {
+-        xStringFeedbackCtl *f = ((xStringFeedbackCtl *) &stuff[1]);
++        xStringFeedbackCtl *f;
+ 
++        REQUEST_AT_LEAST_EXTRA_SIZE(xChangeFeedbackControlReq,
++                                    sizeof(xStringFeedbackCtl));
++        f = ((xStringFeedbackCtl *) &stuff[1]);
+         if (client->swapped) {
+             if (len < bytes_to_int32(sizeof(xStringFeedbackCtl)))
+                 return BadLength;
+-- 
+2.31.1
+
diff --git a/gnu/packages/xorg.scm b/gnu/packages/xorg.scm
index 97ff8ab92b..df0055c704 100644
--- a/gnu/packages/xorg.scm
+++ b/gnu/packages/xorg.scm
@@ -5312,7 +5312,7 @@ over Xlib, including:
          (base32
           "16bwrf0ag41l7jbrllbix8z6avc5yimga7ihvq4ch3a5hb020x4p"))
         (patches
-         (list
+         (cons
           ;; See:
           ;;   https://lists.fedoraproject.org/archives/list/devel@lists.
           ;;      fedoraproject.org/message/JU655YB7AM4OOEQ4MOMCRHJTYJ76VFOK/
@@ -5324,7 +5324,8 @@ over Xlib, including:
             (sha256
              (base32
               "0mm70y058r8s9y9jiv7q2myv0ycnaw3iqzm7d274410s0ik38w7q"))
-            (file-name "xorg-server-use-intel-only-on-pre-gen4.diff"))))))
+            (file-name "xorg-server-use-intel-only-on-pre-gen4.diff"))
+          (search-patches "xorg-server-CVE-2021-3472.patch")))))
     (build-system gnu-build-system)
     (propagated-inputs
       `(("libpciaccess" ,libpciaccess)
-- 
2.31.1