gnu: lrzip: Fix CVE-2017-8842.

* gnu/packages/compression.scm (lrzip)[source]: Add patch.
* gnu/packages/patches/lrzip-CVE-2017-8842.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.

gnu/local.mk

@@ -885,6 +885,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/llvm-3.5-fix-clang-build-with-gcc5.patch	\
   %D%/packages/patches/llvm-for-extempore.patch			\
   %D%/packages/patches/lm-sensors-hwmon-attrs.patch		\
+  %D%/packages/patches/lrzip-CVE-2017-8842.patch		\
   %D%/packages/patches/lua-CVE-2014-5461.patch                      \
   %D%/packages/patches/lua-pkgconfig.patch                      \
   %D%/packages/patches/lua51-liblua-so.patch                    \

gnu/packages/compression.scm

@@ -1017,7 +1017,8 @@ human-readable output.")
              "http://ck.kolivas.org/apps/lrzip/lrzip-" version ".tar.bz2"))
        (sha256
         (base32
-         "0mb449vmmwpkalq732jdyginvql57nxyd31sszb108yps1lf448d"))))
+         "0mb449vmmwpkalq732jdyginvql57nxyd31sszb108yps1lf448d"))
+       (patches (search-patches "lrzip-CVE-2017-8842.patch"))))
     (build-system gnu-build-system)
     (native-inputs
      `(;; nasm is only required when building for 32-bit x86 platforms

gnu/packages/patches/lrzip-CVE-2017-8842.patch

@@ -0,0 +1,23 @@
+From 38386bd482c0a8102a79958cb3eddcb97a167ca3 Mon Sep 17 00:00:00 2001
+From: Con Kolivas <kernel@kolivas.org>
+Date: Fri, 9 Mar 2018 17:39:40 +1100
+Subject: [PATCH] CVE-2017-8842 Fix divide-by-zero in bufRead::get
+
+---
+ libzpaq/libzpaq.h | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/libzpaq/libzpaq.h b/libzpaq/libzpaq.h
+index 93387da..cbe211d 100644
+--- a/libzpaq/libzpaq.h
++++ b/libzpaq/libzpaq.h
+@@ -465,7 +465,8 @@ struct bufRead: public libzpaq::Reader {
+ 
+ 	int get() {
+ 		if (progress && !(*s_len % 128)) {
+-			int pct = (total_len - *s_len) * 100 / total_len;
++			int pct = (total_len > 0) ?
++				(total_len - *s_len) * 100 / total_len : 100;
+ 
+ 			if (pct / 10 != *last_pct / 10) {
+ 				int i;