OpenSSL: don't use direct access to the internal of RSA

OpenSSL 1.1 does not allow us to directly access the internal of
any data type, including RSA. We have to use the defined
functions to do so.

Compatibility with OpenSSL 1.0 is kept by defining the corresponding
functions when they are not found in the library.

Signed-off-by: Emmanuel Deloget <logout@free.fr>
Acked-by: Steffan Karger <steffan.karger@fox-it.com>
Message-Id: <20170612134330.20971-4-logout@free.fr>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg14790.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/configure.ac b/configure.ac
index 43f332b20bd76732c43d7b1b4a8294f8dcad05c0..e9ac5a6e55eead31f4a571094343bd55d059210d 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -928,6 +928,10 @@ if test "${enable_crypto}" = "yes" -a "${with_crypto_library}" = "openssl"; then
                        EVP_PKEY_id \
                        EVP_PKEY_get0_RSA \
                        EVP_PKEY_get0_DSA \
+                       RSA_set_flags \
+                       RSA_bits \
+                       RSA_get0_key \
+                       RSA_set0_key \
                        RSA_meth_new \
                        RSA_meth_free \
                        RSA_meth_set_pub_enc \

diff --git a/src/openvpn/openssl_compat.h b/src/openvpn/openssl_compat.h
index 604985953201f64b8a17c82364389934580ba4ad..e3f20b739e0f3f099ae829dff3940d038ab71ac5 100644 (file)
--- a/src/openvpn/openssl_compat.h
+++ b/src/openvpn/openssl_compat.h
@@ -175,6 +175,106 @@ EVP_PKEY_get0_DSA(EVP_PKEY *pkey)
 }
 #endif
 
+#if !defined(HAVE_RSA_SET_FLAGS)
+/**
+ * Set the RSA flags
+ *
+ * @param rsa                 The RSA object
+ * @param flags               New flags value
+ */
+static inline void
+RSA_set_flags(RSA *rsa, int flags)
+{
+    if (rsa)
+    {
+        rsa->flags = flags;
+    }
+}
+#endif
+
+#if !defined(HAVE_RSA_GET0_KEY)
+/**
+ * Get the RSA parameters
+ *
+ * @param rsa                 The RSA object
+ * @param n                   The @c n parameter
+ * @param e                   The @c e parameter
+ * @param d                   The @c d parameter
+ */
+static inline void
+RSA_get0_key(const RSA *rsa, const BIGNUM **n,
+             const BIGNUM **e, const BIGNUM **d)
+{
+    if (n != NULL)
+    {
+        *n = rsa ? rsa->n : NULL;
+    }
+    if (e != NULL)
+    {
+        *e = rsa ? rsa->e : NULL;
+    }
+    if (d != NULL)
+    {
+        *d = rsa ? rsa->d : NULL;
+    }
+}
+#endif
+
+#if !defined(HAVE_RSA_SET0_KEY)
+/**
+ * Set the RSA parameters
+ *
+ * @param rsa                 The RSA object
+ * @param n                   The @c n parameter
+ * @param e                   The @c e parameter
+ * @param d                   The @c d parameter
+ * @return                    1 on success, 0 on error
+ */
+static inline int
+RSA_set0_key(RSA *rsa, BIGNUM *n, BIGNUM *e, BIGNUM *d)
+{
+    if ((rsa->n == NULL && n == NULL)
+        || (rsa->e == NULL && e == NULL))
+    {
+        return 0;
+    }
+
+    if (n != NULL)
+    {
+        BN_free(rsa->n);
+        rsa->n = n;
+    }
+    if (e != NULL)
+    {
+        BN_free(rsa->e);
+        rsa->e = e;
+    }
+    if (d != NULL)
+    {
+        BN_free(rsa->d);
+        rsa->d = d;
+    }
+
+    return 1;
+}
+#endif
+
+#if !defined(HAVE_RSA_BITS)
+/**
+ * Number of significant RSA bits
+ *
+ * @param rsa                The RSA object ; shall not be NULL
+ * @return                   The number of RSA bits or 0 on error
+ */
+static inline int
+RSA_bits(const RSA *rsa)
+{
+    const BIGNUM *n = NULL;
+    RSA_get0_key(rsa, &n, NULL, NULL);
+    return n ? BN_num_bits(n) : 0;
+}
+#endif
+
 #if !defined(HAVE_RSA_METH_NEW)
 /**
  * Allocate a new RSA method object

diff --git a/src/openvpn/ssl_openssl.c b/src/openvpn/ssl_openssl.c
index c84372d6fb0d8bb2b35af1e648b545c8919b5a93..da801ed5ec78c34f0287aef326d40d3688ac9246 100644 (file)
--- a/src/openvpn/ssl_openssl.c
+++ b/src/openvpn/ssl_openssl.c
@@ -973,10 +973,13 @@ rsa_priv_dec(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, i
 
 /* called at RSA_free */
 static int
-rsa_finish(RSA *rsa)
+openvpn_extkey_rsa_finish(RSA *rsa)
 {
-    RSA_meth_free(rsa->meth);
-    rsa->meth = NULL;
+    /* meth was allocated in tls_ctx_use_external_private_key() ; since
+     * this function is called when the parent RSA object is destroyed,
+     * it is no longer used after this point so kill it. */
+    const RSA_METHOD *meth = RSA_get_method(rsa);
+    RSA_meth_free((RSA_METHOD *)meth);
     return 1;
 }
 
@@ -1058,7 +1061,7 @@ tls_ctx_use_external_private_key(struct tls_root_ctx *ctx,
     RSA_meth_set_priv_enc(rsa_meth, rsa_priv_enc);
     RSA_meth_set_priv_dec(rsa_meth, rsa_priv_dec);
     RSA_meth_set_init(rsa_meth, NULL);
-    RSA_meth_set_finish(rsa_meth, rsa_finish);
+    RSA_meth_set_finish(rsa_meth, openvpn_extkey_rsa_finish);
     RSA_meth_set0_app_data(rsa_meth, NULL);
 
     /* allocate RSA object */
@@ -1075,8 +1078,11 @@ tls_ctx_use_external_private_key(struct tls_root_ctx *ctx,
     pub_rsa = EVP_PKEY_get0_RSA(pkey);
 
     /* initialize RSA object */
-    rsa->n = BN_dup(pub_rsa->n);
-    rsa->flags |= RSA_FLAG_EXT_PKEY;
+    const BIGNUM *n = NULL;
+    const BIGNUM *e = NULL;
+    RSA_get0_key(pub_rsa, &n, &e, NULL);
+    RSA_set0_key(rsa, BN_dup(n), BN_dup(e), NULL);
+    RSA_set_flags(rsa, RSA_flags(rsa) | RSA_FLAG_EXT_PKEY);
     if (!RSA_set_method(rsa, rsa_meth))
     {
         goto err;
@@ -1677,11 +1683,11 @@ print_details(struct key_state_ssl *ks_ssl, const char *prefix)
         EVP_PKEY *pkey = X509_get_pubkey(cert);
         if (pkey != NULL)
         {
-            if (EVP_PKEY_id(pkey) == EVP_PKEY_RSA && EVP_PKEY_get0_RSA(pkey) != NULL
-                && pkey->pkey.rsa->n != NULL)
+            if (EVP_PKEY_id(pkey) == EVP_PKEY_RSA && EVP_PKEY_get0_RSA(pkey) != NULL)
             {
+                RSA *rsa = EVP_PKEY_get0_RSA(pkey);
                 openvpn_snprintf(s2, sizeof(s2), ", %d bit RSA",
-                                 BN_num_bits(pkey->pkey.rsa->n));
+                                 RSA_bits(rsa));
             }
             else if (EVP_PKEY_id(pkey) == EVP_PKEY_DSA && EVP_PKEY_get0_DSA(pkey) != NULL
                      && pkey->pkey.dsa->p != NULL)