From: Arne Schwabe <arne@rfc2549.org>
Date: Fri, 29 Oct 2021 11:11:09 +0000 (+0200)
Subject: Use EVP_PKEY_get_group_name to query group name
X-Git-Tag: v2.6_beta1~402
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4b3c1e76d747d0e7e6aec280680777aef356a940;p=thirdparty%2Fopenvpn.git

Use EVP_PKEY_get_group_name to query group name

EC_Key methods are deprecated in OpenSSL 3.0. Use
EVP_PKEY_get_group_name instead to query the EC group name from an
EVP_PKEY and add a compatibility function for older OpenSSL versions.

Patch v4: adjust compatibility function and remove accidently included
fragment of unrelated patch.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Selva Nair <selva.nair@gmail.com>
Message-Id: <20211029111109.2003101-2-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg23077.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
---

diff --git a/src/openvpn/openssl_compat.h b/src/openvpn/openssl_compat.h
index ce8e2b360..3951d9aca 100644
--- a/src/openvpn/openssl_compat.h
+++ b/src/openvpn/openssl_compat.h
@@ -718,4 +718,40 @@ SSL_CTX_set_max_proto_version(SSL_CTX *ctx, long tls_ver_max)
     return 1;
 }
 #endif /* if OPENSSL_VERSION_NUMBER < 0x10100000L && !defined(ENABLE_CRYPTO_WOLFSSL) */
+
+/* Functionality missing in 1.1.1 */
+#if OPENSSL_VERSION_NUMBER < 0x30000000L && !defined(OPENSSL_NO_EC)
+
+/* Note that this is not a perfect emulation of the new function but
+ * is good enough for our case of printing certificate details during
+ * handshake */
+static inline
+int EVP_PKEY_get_group_name(EVP_PKEY *pkey, char *gname, size_t gname_sz,
+                            size_t *gname_len)
+{
+    const EC_KEY* ec = EVP_PKEY_get0_EC_KEY(pkey);
+    if (ec == NULL)
+    {
+        return 0;
+    }
+    const EC_GROUP* group = EC_KEY_get0_group(ec);
+    int nid = EC_GROUP_get_curve_name(group);
+
+    if (nid == 0)
+    {
+        return 0;
+    }
+    const char *curve = OBJ_nid2sn(nid);
+    if (!curve)
+    {
+        curve = "(error fetching curve name)";
+    }
+
+    strncpynt(gname, curve, gname_sz);
+
+    /* strncpynt ensures null termination so just strlen is fine here */
+    *gname_len = strlen(curve);
+    return 1;
+}
+#endif
 #endif /* OPENSSL_COMPAT_H_ */
diff --git a/src/openvpn/ssl_openssl.c b/src/openvpn/ssl_openssl.c
index 6f2d6d57a..25ff50375 100644
--- a/src/openvpn/ssl_openssl.c
+++ b/src/openvpn/ssl_openssl.c
@@ -2053,13 +2053,15 @@ print_cert_details(X509 *cert, char *buf, size_t buflen)
     int typeid = EVP_PKEY_id(pkey);
 
 #ifndef OPENSSL_NO_EC
-    if (typeid == EVP_PKEY_EC && EVP_PKEY_get0_EC_KEY(pkey) != NULL)
+    char groupname[256];
+    if (typeid == EVP_PKEY_EC)
     {
-        const EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
-        const EC_GROUP *group = EC_KEY_get0_group(ec);
-
-        int nid = EC_GROUP_get_curve_name(group);
-        if (nid == 0 || (curve = OBJ_nid2sn(nid)) == NULL)
+        size_t len;
+        if(EVP_PKEY_get_group_name(pkey, groupname, sizeof(groupname), &len))
+        {
+           curve = groupname;
+        }
+        else
         {
             curve = "(error getting curve name)";
         }