4 files changed, 41 insertions, 24 deletions

diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index 9d503104be3..c8cd81d8537 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -76,6 +76,7 @@ static int	alpn_cb(SSL *ssl,
 					void *userdata);
 static bool initialize_dh(SSL_CTX *context, bool isServerStart);
 static bool initialize_ecdh(SSL_CTX *context, bool isServerStart);
+static const char *SSLerrmessageExt(unsigned long ecode, const char *replacement);
 static const char *SSLerrmessage(unsigned long ecode);
 
 static char *X509_NAME_to_cstring(X509_NAME *name);
@@ -1409,36 +1410,51 @@ static bool
 initialize_ecdh(SSL_CTX *context, bool isServerStart)
 {
 #ifndef OPENSSL_NO_ECDH
-	EC_KEY	   *ecdh;
-	int			nid;
-
-	nid = OBJ_sn2nid(SSLECDHCurve);
-	if (!nid)
-	{
-		ereport(isServerStart ? FATAL : LOG,
-				(errcode(ERRCODE_CONFIG_FILE_ERROR),
-				 errmsg("ECDH: unrecognized curve name: %s", SSLECDHCurve)));
-		return false;
-	}
-
-	ecdh = EC_KEY_new_by_curve_name(nid);
-	if (!ecdh)
+	if (SSL_CTX_set1_groups_list(context, SSLECDHCurve) != 1)
 	{
+		/*
+		 * OpenSSL 3.3.0 introduced proper error messages for group parsing
+		 * errors, earlier versions returns "no SSL error reported" which is
+		 * far from helpful. For older versions, we replace with a better
+		 * error message. Injecting the error into the OpenSSL error queue
+		 * need APIs from OpenSSL 3.0.
+		 */
 		ereport(isServerStart ? FATAL : LOG,
-				(errcode(ERRCODE_CONFIG_FILE_ERROR),
-				 errmsg("ECDH: could not create key")));
+				errcode(ERRCODE_CONFIG_FILE_ERROR),
+				errmsg("failed to set group names specified in ssl_groups: %s",
+					   SSLerrmessageExt(ERR_get_error(),
+										_("No valid groups found"))),
+				errhint("Ensure that each group name is spelled correctly and supported by the installed version of OpenSSL"));
 		return false;
 	}
-
-	SSL_CTX_set_options(context, SSL_OP_SINGLE_ECDH_USE);
-	SSL_CTX_set_tmp_ecdh(context, ecdh);
-	EC_KEY_free(ecdh);
 #endif
 
 	return true;
 }
 
 /*
+ * Obtain reason string for passed SSL errcode with replacement
+ *
+ * The error message supplied in replacement will be used in case the error
+ * code from OpenSSL is 0, else the error message from SSLerrmessage() will
+ * be returned.
+ *
+ * Not all versions of OpenSSL place an error on the queue even for failing
+ * operations, which will yield "no SSL error reported" by SSLerrmessage. This
+ * function can be used to ensure that a proper error message is displayed for
+ * versions reporting no error, while using the OpenSSL error via SSLerrmessage
+ * for versions where there is one.
+ */
+static const char *
+SSLerrmessageExt(unsigned long ecode, const char *replacement)
+{
+	if (ecode == 0)
+		return replacement;
+	else
+		return SSLerrmessage(ecode);
+}
+
+/*
  * Obtain reason string for passed SSL errcode
  *
  * ERR_get_error() is used by caller to get errcode to pass here.
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 507a5d329a3..90e91225b4e 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -190,6 +190,7 @@ static const unit_conversion time_unit_conversion_table[] =
 static const char *const map_old_guc_names[] = {
 	"sort_mem", "work_mem",
 	"vacuum_mem", "maintenance_work_mem",
+	"ssl_ecdh_curve", "ssl_groups",
 	NULL
 };
 
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 2c4cc8cd41b..859e6658e77 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -4656,9 +4656,9 @@ struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"ssl_ecdh_curve", PGC_SIGHUP, CONN_AUTH_SSL,
-			gettext_noop("Sets the curve to use for ECDH."),
-			NULL,
+		{"ssl_groups", PGC_SIGHUP, CONN_AUTH_SSL,
+			gettext_noop("Sets the group(s) to use for Diffie-Hellman key exchange."),
+			gettext_noop("Multiple groups can be specified using colon-separated list."),
 			GUC_SUPERUSER_ONLY
 		},
 		&SSLECDHCurve,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 667e0dc40a2..204eab5f1a7 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -112,7 +112,7 @@
 #ssl_key_file = 'server.key'
 #ssl_ciphers = 'HIGH:MEDIUM:+3DES:!aNULL'	# allowed SSL ciphers
 #ssl_prefer_server_ciphers = on
-#ssl_ecdh_curve = 'prime256v1'
+#ssl_groups = 'prime256v1'
 #ssl_min_protocol_version = 'TLSv1.2'
 #ssl_max_protocol_version = ''
 #ssl_dh_params_file = ''