Based on:
https://sourceware.org/bugzilla/show_bug.cgi?id=CVE-2017-1000366
https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=patch;h=efa26d9c13a6fabd34a05139e1d8b2e441b2fae9

From efa26d9c13a6fabd34a05139e1d8b2e441b2fae9 Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Mon, 19 Jun 2017 18:34:53 +0200
Subject: [PATCH] CVE-2017-1000366: Ignore LD_LIBRARY_PATH for AT_SECURE=1
 programs [BZ #21624]

LD_LIBRARY_PATH can only be used to reorder system search paths, which
is not useful functionality.

This makes an exploitable unbounded alloca in _dl_init_paths unreachable
for AT_SECURE=1 programs.

---
 ChangeLog  | 7 +++++++
 NEWS       | 1 +
 elf/rtld.c | 3 ++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/elf/rtld.c b/elf/rtld.c
index 647661c..215a9ae 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -2437,7 +2437,8 @@ process_envvars (enum mode *modep)
 
 	case 12:
 	  /* The library search path.  */
-	  if (memcmp (envline, "LIBRARY_PATH", 12) == 0)
+	  if (!__libc_enable_secure
+	      && memcmp (envline, "LIBRARY_PATH", 12) == 0)
 	    {
 	      library_path = &envline[13];
 	      break;
-- 
2.9.3

