08/08: gnu: libxvmc: Fix CVE-2016-7953.

[Leo Famulari]

lfam pushed a commit to branch master
in repository guix.

commit 813062a5f714ddbdb3860b7d51c10f4ddc3bfb61
Author: Leo Famulari <address@hidden>
Date:   Wed Oct 5 13:33:11 2016 -0400

    gnu: libxvmc: Fix CVE-2016-7953.
    
    * gnu/packages/patches/libxvmc-CVE-2016-7953.patch: New file.
    * gnu/local.mk (dist_patch_DATA): Add it.
    * gnu/packages/xorg.scm (libxvmc)[replacement]: New field.
    (libxvmc/fixed): New variable.
---
 gnu/local.mk                                     |    1 +
 gnu/packages/patches/libxvmc-CVE-2016-7953.patch |   42 ++++++++++++++++++++++
 gnu/packages/xorg.scm                            |    8 +++++
 3 files changed, 51 insertions(+)

diff --git a/gnu/local.mk b/gnu/local.mk
index 92b5e66..867946d 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -678,6 +678,7 @@ dist_patch_DATA =                                           
\
   %D%/packages/patches/libxrender-CVE-2016-7950.patch          \
   %D%/packages/patches/libxtst-CVE-2016-7951-CVE-2016-7952.patch       \
   %D%/packages/patches/libxv-CVE-2016-5407.patch               \
+  %D%/packages/patches/libxvmc-CVE-2016-7953.patch             \
   %D%/packages/patches/libxslt-generated-ids.patch             \
   %D%/packages/patches/lirc-localstatedir.patch                        \
   %D%/packages/patches/llvm-for-extempore.patch                        \
diff --git a/gnu/packages/patches/libxvmc-CVE-2016-7953.patch 
b/gnu/packages/patches/libxvmc-CVE-2016-7953.patch
new file mode 100644
index 0000000..737abde
--- /dev/null
+++ b/gnu/packages/patches/libxvmc-CVE-2016-7953.patch
@@ -0,0 +1,42 @@
+Fix CVE-2016-7953:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7953
+
+Patch copied from upstream source repository:
+
+https://cgit.freedesktop.org/xorg/lib/libXvMC/commit/?id=2cd95e7da8367cccdcdd5c9b160012d1dec5cbdb
+
+From 2cd95e7da8367cccdcdd5c9b160012d1dec5cbdb Mon Sep 17 00:00:00 2001
+From: Tobias Stoeckmann <address@hidden>
+Date: Sun, 25 Sep 2016 22:34:27 +0200
+Subject: [PATCH] Avoid buffer underflow on empty strings.
+
+If an empty string is received from an x-server, do not underrun the
+buffer by accessing "rep.nameLen - 1" unconditionally, which could end
+up being -1.
+
+Signed-off-by: Tobias Stoeckmann <address@hidden>
+Reviewed-by: Matthieu Herrb <address@hidden>
+---
+ src/XvMC.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/src/XvMC.c b/src/XvMC.c
+index 7336760..3ee4212 100644
+--- a/src/XvMC.c
++++ b/src/XvMC.c
+@@ -576,9 +576,9 @@ Status XvMCGetDRInfo(Display *dpy, XvPortID port,
+       if (*name && *busID && tmpBuf) {
+           _XRead(dpy, tmpBuf, realSize);
+           strncpy(*name,tmpBuf,rep.nameLen);
+-          (*name)[rep.nameLen - 1] = '\0';
++          (*name)[rep.nameLen == 0 ? 0 : rep.nameLen - 1] = '\0';
+           strncpy(*busID,tmpBuf+rep.nameLen,rep.busIDLen);
+-          (*busID)[rep.busIDLen - 1] = '\0';
++          (*busID)[rep.busIDLen == 0 ? 0 : rep.busIDLen - 1] = '\0';
+           XFree(tmpBuf);
+       } else {
+           XFree(*name);
+-- 
+2.10.1
+
diff --git a/gnu/packages/xorg.scm b/gnu/packages/xorg.scm
index 448ac65..aa2b99a 100644
--- a/gnu/packages/xorg.scm
+++ b/gnu/packages/xorg.scm
@@ -4998,6 +4998,7 @@ new API's in libXft, or the legacy API's in libX11.")
 (define-public libxvmc
   (package
     (name "libxvmc")
+    (replacement libxvmc/fixed)
     (version "1.0.9")
     (source
       (origin
@@ -5023,6 +5024,13 @@ new API's in libXft, or the legacy API's in libX11.")
     (description "Xorg XvMC library.")
     (license license:x11)))
 
+(define libxvmc/fixed
+  (package
+    (inherit libxvmc)
+    (source (origin
+              (inherit (package-source libxvmc))
+              (patches (search-patches
+                         "libxvmc-CVE-2016-7953.patch"))))))
 
 (define-public libxxf86vm
   (package