[Openvpn-devel] [PATCH 3/7] OpenSSL: don't use direct access to the internal of RSA

[Emmanuel Deloget <logout@...260...>]

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@...260...>
---
 configure.ac                 |  3 ++
 src/openvpn/openssl_compat.h | 84 ++++++++++++++++++++++++++++++++++++++++++++
 src/openvpn/ssl_openssl.c    | 24 ++++++++-----
 3 files changed, 103 insertions(+), 8 deletions(-)

diff --git a/configure.ac b/configure.ac
index a92e8142..e4c053c8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -929,6 +929,9 @@ 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_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 0d82cf25..29cd13a4 100644
--- a/src/openvpn/openssl_compat.h
+++ b/src/openvpn/openssl_compat.h
@@ -176,6 +176,90 @@ 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_METH_NEW)
 /**
  * Allocate a new RSA method object
diff --git a/src/openvpn/ssl_openssl.c b/src/openvpn/ssl_openssl.c
index 1c73641c..48479c0d 100644
--- a/src/openvpn/ssl_openssl.c
+++ b/src/openvpn/ssl_openssl.c
@@ -975,8 +975,8 @@ rsa_priv_dec(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, i
 static int
 rsa_finish(RSA *rsa)
 {
-    RSA_meth_free(rsa->meth);
-    rsa->meth = NULL;
+    const RSA_METHOD *meth = RSA_get_method(rsa);
+    RSA_meth_free((RSA_METHOD *)meth);
     return 1;
 }
 
@@ -1075,8 +1075,11 @@ 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 +1680,16 @@ 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)
             {
-                openvpn_snprintf(s2, sizeof(s2), ", %d bit RSA",
-                                 BN_num_bits(pkey->pkey.rsa->n));
+                RSA *rsa = EVP_PKEY_get0_RSA(pkey);
+                const BIGNUM *n = NULL;
+                RSA_get0_key(rsa, &n, NULL, NULL);
+                if (n != NULL)
+                {
+                    openvpn_snprintf(s2, sizeof(s2), ", %d bit RSA",
+                                     BN_num_bits(n));
+                }
             }
             else if (EVP_PKEY_id(pkey) == EVP_PKEY_DSA && EVP_PKEY_get0_DSA(pkey) != NULL
                      && pkey->pkey.dsa->p != NULL)
-- 
2.11.0