[OpenWrt-Devel] [PATCH] tools/patch: apply upstream patch for cve-2019-13638

[Russell Senior]

GNU patch through 2.7.6 is vulnerable to OS shell command injection that
can be exploited by opening a crafted patch file that contains an ed style
diff payload with shell metacharacters. The ed editor does not need to be
present on the vulnerable system. This is different from CVE-2018-1000156.

https://nvd.nist.gov/vuln/detail/CVE-2019-13638

Signed-off-by: Russell Senior <russell at personaltelco.net>
---
 tools/patch/Makefile                         |  2 +-
 tools/patch/patches/060-CVE-2019-13638.patch | 38 ++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 tools/patch/patches/060-CVE-2019-13638.patch

diff --git a/tools/patch/Makefile b/tools/patch/Makefile
index 3bcf668b04..e0481204f7 100644
--- a/tools/patch/Makefile
+++ b/tools/patch/Makefile
@@ -8,7 +8,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=patch
 PKG_VERSION:=2.7.6
-PKG_RELEASE:=5
+PKG_RELEASE:=6
 PKG_CPE_ID:=cpe:/a:gnu:patch
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
diff --git a/tools/patch/patches/060-CVE-2019-13638.patch b/tools/patch/patches/060-CVE-2019-13638.patch
new file mode 100644
index 0000000000..38caff628a
--- /dev/null
+++ b/tools/patch/patches/060-CVE-2019-13638.patch
@@ -0,0 +1,38 @@
+From 3fcd042d26d70856e826a42b5f93dc4854d80bf0 Mon Sep 17 00:00:00 2001
+From: Andreas Gruenbacher <agruen at gnu.org>
+Date: Fri, 6 Apr 2018 19:36:15 +0200
+Subject: Invoke ed directly instead of using the shell
+
+* src/pch.c (do_ed_script): Invoke ed directly instead of using a shell
+command to avoid quoting vulnerabilities.
+---
+ src/pch.c | 6 ++----
+ 1 file changed, 2 insertions(+), 4 deletions(-)
+
+diff --git a/src/pch.c b/src/pch.c
+index 4fd5a05..16e001a 100644
+--- a/src/pch.c
++++ b/src/pch.c
+@@ -2459,9 +2459,6 @@ do_ed_script (char const *inname, char const *outname,
+ 	    *outname_needs_removal = true;
+ 	    copy_file (inname, outname, 0, exclusive, instat.st_mode, true);
+ 	  }
+-	sprintf (buf, "%s %s%s", editor_program,
+-		 verbosity == VERBOSE ? "" : "- ",
+-		 outname);
+ 	fflush (stdout);
+ 
+ 	pid = fork();
+@@ -2470,7 +2467,8 @@ do_ed_script (char const *inname, char const *outname,
+ 	else if (pid == 0)
+ 	  {
+ 	    dup2 (tmpfd, 0);
+-	    execl ("/bin/sh", "sh", "-c", buf, (char *) 0);
++	    assert (outname[0] != '!' && outname[0] != '-');
++	    execlp (editor_program, editor_program, "-", outname, (char  *) NULL);
+ 	    _exit (2);
+ 	  }
+ 	else
+-- 
+cgit v1.0-41-gc330
+
-- 
2.22.0



-- 
Russell Senior, President
russell at personaltelco.net

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