Use secure_getenv(3) when available.

Change all calls to getenv() inside libcrypto to use a new wrapper function
that use secure_getenv() if available and an issetugid then getenv if not.

CPU processor override flags are unchanged.

Extra checks for OPENSSL_issetugid() have been removed in favour of the
safe getenv.

Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/7047)

1 files changed, 31 insertions, 0 deletions

diff --git a/crypto/getenv.c b/crypto/getenv.c
new file mode 100644
index 0000000000..7e98b645b0
--- /dev/null
+++ b/crypto/getenv.c
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
+
+#include <stdlib.h>
+#include "internal/cryptlib.h"
+
+char *ossl_safe_getenv(const char *name)
+{
+#if defined(__GLIBC__) && defined(__GLIBC_PREREQ)
+# if __GLIBC_PREREQ(2, 17)
+#  define SECURE_GETENV
+    return secure_getenv(name);
+# endif
+#endif
+
+#ifndef SECURE_GETENV
+    if (OPENSSL_issetugid())
+        return NULL;
+    return getenv(name);
+#endif
+}