[PATCH 1/1] gnu: cracklib: Fix CVE-2016-6318.

[Leo Famulari <leo@famulari.name>]

* gnu/packages/patches/cracklib-CVE-2016-6318.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/password-utils.scm (cracklib)[source]: Use the patch.
---
 gnu/local.mk                                      |  1 +
 gnu/packages/password-utils.scm                   |  2 +
 gnu/packages/patches/cracklib-CVE-2016-6318.patch | 95 +++++++++++++++++++++++
 3 files changed, 98 insertions(+)
 create mode 100644 gnu/packages/patches/cracklib-CVE-2016-6318.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index 7416850..d890046 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -464,6 +464,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/cpio-gets-undeclared.patch		\
   %D%/packages/patches/cpio-CVE-2016-2037.patch			\
   %D%/packages/patches/cpufrequtils-fix-aclocal.patch		\
+  %D%/packages/patches/cracklib-CVE-2016-6318.patch		\
   %D%/packages/patches/crda-optional-gcrypt.patch		\
   %D%/packages/patches/crossmap-allow-system-pysam.patch	\
   %D%/packages/patches/csound-header-ordering.patch		\
diff --git a/gnu/packages/password-utils.scm b/gnu/packages/password-utils.scm
index 7a8bdcb..7288da6 100644
--- a/gnu/packages/password-utils.scm
+++ b/gnu/packages/password-utils.scm
@@ -29,6 +29,7 @@
   #:use-module (guix build-system gnu)
   #:use-module (guix download)
   #:use-module (guix packages)
+  #:use-module (gnu packages)
   #:use-module (gnu packages admin)
   #:use-module (gnu packages base)
   #:use-module (gnu packages compression)
@@ -159,6 +160,7 @@ and vice versa.")
               (uri (string-append "https://github.com/cracklib/cracklib/"
                                   "releases/download/" name "-" version "/"
                                   name "-" version ".tar.gz"))
+              (patches (search-patches "cracklib-CVE-2016-6318.patch"))
               (sha256
                (base32
                 "0hrkb0prf7n92w6rxgq0ilzkk6rkhpys2cfqkrbzswp27na7dkqp"))))
diff --git a/gnu/packages/patches/cracklib-CVE-2016-6318.patch b/gnu/packages/patches/cracklib-CVE-2016-6318.patch
new file mode 100644
index 0000000..4806eca
--- /dev/null
+++ b/gnu/packages/patches/cracklib-CVE-2016-6318.patch
@@ -0,0 +1,95 @@
+Fix CVE-2016-6318.
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-6318
+
+Patch copied from Red Hat:
+
+https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2016-6318
+https://bugzilla.redhat.com/attachment.cgi?id=1188599&action=diff
+
+It is not safe to pass words longer than STRINGSIZE further to cracklib
+so the longbuffer cannot be longer than STRINGSIZE.
+diff -up cracklib-2.9.0/lib/fascist.c.longgecos cracklib-2.9.0/lib/fascist.c
+--- cracklib-2.9.0/lib/fascist.c.longgecos	2014-02-06 16:03:59.000000000 +0100
++++ cracklib-2.9.0/lib/fascist.c	2016-08-08 12:05:40.279235815 +0200
+@@ -515,7 +515,7 @@ FascistGecosUser(char *password, const c
+     char gbuffer[STRINGSIZE];
+     char tbuffer[STRINGSIZE];
+     char *uwords[STRINGSIZE];
+-    char longbuffer[STRINGSIZE * 2];
++    char longbuffer[STRINGSIZE];
+ 
+     if (gecos == NULL)
+ 	gecos = "";
+@@ -596,38 +596,47 @@ FascistGecosUser(char *password, const c
+     {
+ 	for (i = 0; i < j; i++)
+ 	{
+-	    strcpy(longbuffer, uwords[i]);
+-	    strcat(longbuffer, uwords[j]);
+-
+-	    if (GTry(longbuffer, password))
++	    if (strlen(uwords[i]) + strlen(uwords[j]) < STRINGSIZE)
+ 	    {
+-		return _("it is derived from your password entry");
+-	    }
+-
+-	    strcpy(longbuffer, uwords[j]);
+-	    strcat(longbuffer, uwords[i]);
++		strcpy(longbuffer, uwords[i]);
++		strcat(longbuffer, uwords[j]);
+ 
+-	    if (GTry(longbuffer, password))
+-	    {
+-		return _("it's derived from your password entry");
++		if (GTry(longbuffer, password))
++		{
++		    return _("it is derived from your password entry");
++		}
++
++		strcpy(longbuffer, uwords[j]);
++		strcat(longbuffer, uwords[i]);
++
++		if (GTry(longbuffer, password))
++		{
++		   return _("it's derived from your password entry");
++		}
+ 	    }
+ 
+-	    longbuffer[0] = uwords[i][0];
+-	    longbuffer[1] = '\0';
+-	    strcat(longbuffer, uwords[j]);
+-
+-	    if (GTry(longbuffer, password))
++	    if (strlen(uwords[j]) < STRINGSIZE - 1)
+ 	    {
+-		return _("it is derivable from your password entry");
++		longbuffer[0] = uwords[i][0];
++		longbuffer[1] = '\0';
++		strcat(longbuffer, uwords[j]);
++
++		if (GTry(longbuffer, password))
++		{
++		    return _("it is derivable from your password entry");
++		}
+ 	    }
+ 
+-	    longbuffer[0] = uwords[j][0];
+-	    longbuffer[1] = '\0';
+-	    strcat(longbuffer, uwords[i]);
+-
+-	    if (GTry(longbuffer, password))
++	    if (strlen(uwords[i]) < STRINGSIZE - 1)
+ 	    {
+-		return _("it's derivable from your password entry");
++		longbuffer[0] = uwords[j][0];
++		longbuffer[1] = '\0';
++		strcat(longbuffer, uwords[i]);
++
++		if (GTry(longbuffer, password))
++		{
++		    return _("it's derivable from your password entry");
++		}
+ 	    }
+ 	}
+     }
-- 
2.9.3