patch: fix CVE-2019-20633

* CVE detail: https://nvd.nist.gov/vuln/detail/CVE-2019-20633

* upstream tracking: https://savannah.gnu.org/bugs/index.php?56683

* Fixes potential for double free after incomplete fix for CVE-2018-6952
  - src/pch.c (another_hunk): Avoid invalid memory access in context format
    diffs.

(From OE-Core rev: af4fbea9a1656bdf95d85831cae13cae3a60d5ee)

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit be71dd2cc16a4c0d244a76a748f08ca0d9bfeba0)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/patch/patch/CVE-2019-20633.patch

@@ -0,0 +1,31 @@
+From 15b158db3ae11cb835f2eb8d2eb48e09d1a4af48 Mon Sep 17 00:00:00 2001
+From: Andreas Gruenbacher <agruen@gnu.org>
+Date: Mon, 15 Jul 2019 19:10:02 +0200
+Subject: Avoid invalid memory access in context format diffs
+
+* src/pch.c (another_hunk): Avoid invalid memory access in context format
+diffs.
+
+CVE: CVE-2019-20633
+Upstream-Status: Backport[https://git.savannah.gnu.org/cgit/patch.git/patch/?id=15b158db3ae11cb835f2eb8d2eb48e09d1a4af48]
+Signed-off-by: Scott Murray <scott.murray@konsulko.com>
+
+---
+ src/pch.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/src/pch.c b/src/pch.c
+index a500ad9..cb54e03 100644
+--- a/src/pch.c
++++ b/src/pch.c
+@@ -1328,6 +1328,7 @@ another_hunk (enum diff difftype, bool rev)
+ 		  ptrn_prefix_context = context;
+ 		ptrn_suffix_context = context;
+ 		if (repl_beginning
++		    || p_end <= 0
+ 		    || (p_end
+ 			!= p_ptrn_lines + 1 + (p_Char[p_end - 1] == '\n')))
+ 		  {
+-- 
+cgit v1.2.1
+

meta/recipes-devtools/patch/patch_2.7.6.bb

@@ -10,6 +10,7 @@ SRC_URI += "file://0001-Unset-need_charset_alias-when-building-for-musl.patch \
             file://0001-Invoke-ed-directly-instead-of-using-the-shell.patch \
             file://0001-Don-t-leak-temporary-file-on-failed-ed-style-patch.patch \
             file://0001-Don-t-leak-temporary-file-on-failed-multi-file-ed.patch \
+            file://CVE-2019-20633.patch \
 "
 
 SRC_URI[md5sum] = "4c68cee989d83c87b00a3860bcd05600"