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)

(cherry picked from commit 5c39a55d04ea6e6f734b627a050b9e702788d50d)

11 files changed, 54 insertions, 26 deletions

diff --git a/crypto/build.info b/crypto/build.info
index b515b7318e..2c619c62e8 100644
--- a/crypto/build.info
+++ b/crypto/build.info
@@ -2,7 +2,7 @@ LIBS=../libcrypto
 SOURCE[../libcrypto]=\
         cryptlib.c mem.c mem_dbg.c cversion.c ex_data.c cpt_err.c \
         ebcdic.c uid.c o_time.c o_str.c o_dir.c o_fopen.c ctype.c \
-        threads_pthread.c threads_win.c threads_none.c \
+        threads_pthread.c threads_win.c threads_none.c getenv.c \
         o_init.c o_fips.c mem_sec.c init.c {- $target{cpuid_asm_src} -} \
         {- $target{uplink_aux_src} -}
 EXTRA=  ../ms/uplink-x86.pl ../ms/uplink.c ../ms/applink.c \
diff --git a/crypto/conf/conf_api.c b/crypto/conf/conf_api.c
index 72fe2da1ad..5e57d749ce 100644
--- a/crypto/conf/conf_api.c
+++ b/crypto/conf/conf_api.c
@@ -10,6 +10,7 @@
 /* Part of the code in here was originally in conf.c, which is now removed */
 
 #include "e_os.h"
+#include "internal/cryptlib.h"
 #include <stdlib.h>
 #include <string.h>
 #include <openssl/conf.h>
@@ -82,7 +83,7 @@ char *_CONF_get_string(const CONF *conf, const char *section,
             if (v != NULL)
                 return v->value;
             if (strcmp(section, "ENV") == 0) {
-                p = getenv(name);
+                p = ossl_safe_getenv(name);
                 if (p != NULL)
                     return p;
             }
@@ -95,7 +96,7 @@ char *_CONF_get_string(const CONF *conf, const char *section,
         else
             return NULL;
     } else
-        return getenv(name);
+        return ossl_safe_getenv(name);
 }
 
 static unsigned long conf_value_hash(const CONF_VALUE *v)
diff --git a/crypto/conf/conf_mod.c b/crypto/conf/conf_mod.c
index df53609cc4..51f262e774 100644
--- a/crypto/conf/conf_mod.c
+++ b/crypto/conf/conf_mod.c
@@ -480,11 +480,8 @@ char *CONF_get1_default_config_file(void)
     char *file, *sep = "";
     int len;
 
-    if (!OPENSSL_issetugid()) {
-        file = getenv("OPENSSL_CONF");
-        if (file)
-            return OPENSSL_strdup(file);
-    }
+    if ((file = ossl_safe_getenv("OPENSSL_CONF")) != NULL)
+        return OPENSSL_strdup(file);
 
     len = strlen(X509_get_default_cert_area());
 #ifndef OPENSSL_SYS_VMS
diff --git a/crypto/ct/ct_log.c b/crypto/ct/ct_log.c
index be6681dca7..c1bca3e141 100644
--- a/crypto/ct/ct_log.c
+++ b/crypto/ct/ct_log.c
@@ -137,7 +137,7 @@ static int ctlog_new_from_conf(CTLOG **ct_log, const CONF *conf, const char *sec
 
 int CTLOG_STORE_load_default_file(CTLOG_STORE *store)
 {
-    const char *fpath = getenv(CTLOG_FILE_EVP);
+    const char *fpath = ossl_safe_getenv(CTLOG_FILE_EVP);
 
     if (fpath == NULL)
       fpath = CTLOG_FILE;
diff --git a/crypto/engine/eng_list.c b/crypto/engine/eng_list.c
index 4bc7ea173c..45c339c541 100644
--- a/crypto/engine/eng_list.c
+++ b/crypto/engine/eng_list.c
@@ -317,8 +317,7 @@ ENGINE *ENGINE_by_id(const char *id)
      * Prevent infinite recursion if we're looking for the dynamic engine.
      */
     if (strcmp(id, "dynamic")) {
-        if (OPENSSL_issetugid()
-                || (load_dir = getenv("OPENSSL_ENGINES")) == NULL)
+        if ((load_dir = ossl_safe_getenv("OPENSSL_ENGINES")) == NULL)
             load_dir = ENGINESDIR;
         iterator = ENGINE_by_id("dynamic");
         if (!iterator || !ENGINE_ctrl_cmd_string(iterator, "ID", id, 0) ||
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
+}
diff --git a/crypto/pkcs12/p12_mutl.c b/crypto/pkcs12/p12_mutl.c
index 88d1d66324..0cbbed364a 100644
--- a/crypto/pkcs12/p12_mutl.c
+++ b/crypto/pkcs12/p12_mutl.c
@@ -7,13 +7,13 @@
  * https://www.openssl.org/source/license.html
  */
 
-# include <stdio.h>
-# include "internal/cryptlib.h"
-# include <openssl/crypto.h>
-# include <openssl/hmac.h>
-# include <openssl/rand.h>
-# include <openssl/pkcs12.h>
-# include "p12_lcl.h"
+#include <stdio.h>
+#include "internal/cryptlib.h"
+#include <openssl/crypto.h>
+#include <openssl/hmac.h>
+#include <openssl/rand.h>
+#include <openssl/pkcs12.h>
+#include "p12_lcl.h"
 
 int PKCS12_mac_present(const PKCS12 *p12)
 {
@@ -44,7 +44,7 @@ void PKCS12_get0_mac(const ASN1_OCTET_STRING **pmac,
     }
 }
 
-# define TK26_MAC_KEY_LEN 32
+#define TK26_MAC_KEY_LEN 32
 
 static int pkcs12_gen_gost_mac_key(const char *pass, int passlen,
                                    const unsigned char *salt, int saltlen,
@@ -112,7 +112,7 @@ static int pkcs12_gen_mac(PKCS12 *p12, const char *pass, int passlen,
     if ((md_type_nid == NID_id_GostR3411_94
          || md_type_nid == NID_id_GostR3411_2012_256
          || md_type_nid == NID_id_GostR3411_2012_512)
-        && !getenv("LEGACY_GOST_PKCS12")) {
+        && ossl_safe_getenv("LEGACY_GOST_PKCS12") == NULL) {
         md_size = TK26_MAC_KEY_LEN;
         if (!pkcs12_gen_gost_mac_key(pass, passlen, salt, saltlen, iter,
                                      md_size, key, md_type)) {
diff --git a/crypto/rand/randfile.c b/crypto/rand/randfile.c
index c652ddcf1e..89720eb5cf 100644
--- a/crypto/rand/randfile.c
+++ b/crypto/rand/randfile.c
@@ -262,11 +262,9 @@ const char *RAND_file_name(char *buf, size_t size)
         }
     }
 #else
-    if (OPENSSL_issetugid() != 0) {
+    if ((s = ossl_safe_getenv("RANDFILE")) == NULL || *s == '\0') {
         use_randfile = 0;
-    } else if ((s = getenv("RANDFILE")) == NULL || *s == '\0') {
-        use_randfile = 0;
-        s = getenv("HOME");
+        s = ossl_safe_getenv("HOME");
     }
 #endif
 
diff --git a/crypto/x509/by_dir.c b/crypto/x509/by_dir.c
index 11ac52ce3c..b3760dbadf 100644
--- a/crypto/x509/by_dir.c
+++ b/crypto/x509/by_dir.c
@@ -73,7 +73,7 @@ static int dir_ctrl(X509_LOOKUP *ctx, int cmd, const char *argp, long argl,
     switch (cmd) {
     case X509_L_ADD_DIR:
         if (argl == X509_FILETYPE_DEFAULT) {
-            const char *dir = getenv(X509_get_default_cert_dir_env());
+            const char *dir = ossl_safe_getenv(X509_get_default_cert_dir_env());
 
             if (dir)
                 ret = add_cert_dir(ld, dir, X509_FILETYPE_PEM);
diff --git a/crypto/x509/by_file.c b/crypto/x509/by_file.c
index 78d7fbdf44..244512c935 100644
--- a/crypto/x509/by_file.c
+++ b/crypto/x509/by_file.c
@@ -46,7 +46,7 @@ static int by_file_ctrl(X509_LOOKUP *ctx, int cmd, const char *argp,
     switch (cmd) {
     case X509_L_FILE_LOAD:
         if (argl == X509_FILETYPE_DEFAULT) {
-            file = getenv(X509_get_default_cert_file_env());
+            file = ossl_safe_getenv(X509_get_default_cert_file_env());
             if (file)
                 ok = (X509_load_cert_crl_file(ctx, file,
                                               X509_FILETYPE_PEM) != 0);
diff --git a/include/internal/cryptlib.h b/include/internal/cryptlib.h
index a608735187..329ef62014 100644
--- a/include/internal/cryptlib.h
+++ b/include/internal/cryptlib.h
@@ -81,6 +81,8 @@ void OPENSSL_showfatal(const char *fmta, ...);
 void crypto_cleanup_all_ex_data_int(void);
 int openssl_init_fork_handlers(void);
 
+char *ossl_safe_getenv(const char *name);
+
 extern CRYPTO_RWLOCK *memdbg_lock;
 int openssl_strerror_r(int errnum, char *buf, size_t buflen);
 # if !defined(OPENSSL_NO_STDIO)