2 files changed, 22 insertions, 9 deletions

diff --git a/lib/secure_getenv.c b/lib/secure_getenv.c
index f359ab2173b..88a60dc33c3 100644
--- a/lib/secure_getenv.c
+++ b/lib/secure_getenv.c
@@ -1,4 +1,4 @@
-/* Look up an environment variable more securely.
+/* Look up an environment variable, returning NULL in insecure situations.
 
    Copyright 2013-2016 Free Software Foundation, Inc.
 
@@ -20,22 +20,35 @@
 #include <stdlib.h>
 
 #if !HAVE___SECURE_GETENV
-# if HAVE_ISSETUGID
+# if HAVE_ISSETUGID || (HAVE_GETUID && HAVE_GETEUID && HAVE_GETGID && HAVE_GETEGID)
 #  include <unistd.h>
-# else
-#  undef issetugid
-#  define issetugid() 1
 # endif
 #endif
 
 char *
 secure_getenv (char const *name)
 {
-#if HAVE___SECURE_GETENV
+#if HAVE___SECURE_GETENV /* glibc */
   return __secure_getenv (name);
-#else
+#elif HAVE_ISSETUGID /* OS X, FreeBSD, NetBSD, OpenBSD */
   if (issetugid ())
-    return 0;
+    return NULL;
+  return getenv (name);
+#elif HAVE_GETUID && HAVE_GETEUID && HAVE_GETGID && HAVE_GETEGID /* other Unix */
+  if (geteuid () != getuid () || getegid () != getgid ())
+    return NULL;
   return getenv (name);
+#elif (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ /* native Windows */
+  /* On native Windows, there is no such concept as setuid or setgid binaries.
+     - Programs launched as system services have high privileges, but they don't
+       inherit environment variables from a user.
+     - Programs launched by a user with "Run as Administrator" have high
+       privileges and use the environment variables, but the user has been asked
+       whether he agrees.
+     - Programs launched by a user without "Run as Administrator" cannot gain
+       high privileges, therefore there is no risk. */
+  return getenv (name);
+#else
+  return NULL;
 #endif
 }
diff --git a/lib/verify.h b/lib/verify.h
index 2f4383743bb..5c8381d2906 100644
--- a/lib/verify.h
+++ b/lib/verify.h
@@ -263,7 +263,7 @@ template <int w>
 # define assume(R) ((R) ? (void) 0 : __builtin_unreachable ())
 #elif 1200 <= _MSC_VER
 # define assume(R) __assume (R)
-#elif (defined lint \
+#elif ((defined GCC_LINT || defined lint) \
        && (__has_builtin (__builtin_trap) \
            || 3 < __GNUC__ + (3 < __GNUC_MINOR__ + (4 <= __GNUC_PATCHLEVEL__))))
   /* Doing it this way helps various packages when configured with