gnu: fribidi: Fix CVE-2019-18397.

* gnu/packages/fribidi.scm (fribidi): Replace with fribidi/fixed.
(fribidi/fixed): New variable.
* gnu/packages/patches/fribidi-CVE-2019-18397.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register it.

gnu/local.mk

@@ -838,6 +838,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/flint-ldconfig.patch			\
   %D%/packages/patches/foomatic-filters-CVE-2015-8327.patch	\
   %D%/packages/patches/foomatic-filters-CVE-2015-8560.patch	\
+  %D%/packages/patches/fribidi-CVE-2019-18397.patch		\
   %D%/packages/patches/freeimage-unbundle.patch		\
   %D%/packages/patches/fuse-overlapping-headers.patch				\
   %D%/packages/patches/gawk-shell.patch				\

gnu/packages/fribidi.scm

@@ -1,6 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2014 Marek Benc <merkur32@gmail.com>
-;;; Copyright © 2016 Efraim Flashner <efraim@flashner.co.il>
+;;; Copyright © 2016, 2019 Efraim Flashner <efraim@flashner.co.il>
 ;;; Copyright © 2018 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;;
 ;;; This file is part of GNU Guix.
@@ -22,10 +22,12 @@
   #:use-module (guix packages)
   #:use-module (guix download)
   #:use-module (guix build-system gnu)
-  #:use-module (guix licenses))
+  #:use-module (guix licenses)
+  #:use-module (gnu packages))
 
 (define-public fribidi
   (package
+    (replacement fribidi/fixed)
     (name "fribidi")
     (version "1.0.5")
     (source
@@ -45,3 +47,10 @@ Algorithm.  This algorithm is used to properly display text in left-to-right
 or right-to-left ordering as necessary.")
     (home-page "https://github.com/fribidi/fribidi")
     (license lgpl2.1+)))
+
+(define fribidi/fixed
+  (package
+    (inherit fribidi)
+    (source
+      (origin (inherit (package-source fribidi))
+              (patches (search-patches "fribidi-CVE-2019-18397.patch"))))))

gnu/packages/patches/fribidi-CVE-2019-18397.patch

@@ -0,0 +1,26 @@
+https://github.com/fribidi/fribidi/commit/034c6e9a1d296286305f4cfd1e0072b879f52568.patch
+
+From 034c6e9a1d296286305f4cfd1e0072b879f52568 Mon Sep 17 00:00:00 2001
+From: Dov Grobgeld <dov.grobgeld@gmail.com>
+Date: Thu, 24 Oct 2019 09:37:29 +0300
+Subject: [PATCH] Truncate isolate_level to FRIBIDI_BIDI_MAX_EXPLICIT_LEVEL
+
+---
+ lib/fribidi-bidi.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/lib/fribidi-bidi.c b/lib/fribidi-bidi.c
+index 6c84392..d384878 100644
+--- a/lib/fribidi-bidi.c
++++ b/lib/fribidi-bidi.c
+@@ -747,7 +747,9 @@ fribidi_get_par_embedding_levels_ex (
+             }
+ 
+ 	  RL_LEVEL (pp) = level;
+-          RL_ISOLATE_LEVEL (pp) = isolate_level++;
++          RL_ISOLATE_LEVEL (pp) = isolate_level;
++          if (isolate_level < FRIBIDI_BIDI_MAX_EXPLICIT_LEVEL-1)
++              isolate_level++;
+           base_level_per_iso_level[isolate_level] = new_level;
+ 
+ 	  if (!FRIBIDI_IS_NEUTRAL (override))