Verify remote SSL certificate

ngx_http_auth_ldap_module.c

@@ -1218,10 +1218,22 @@ ngx_http_auth_ldap_ssl_handshake_handler(ngx_connection_t *conn)
     c = conn->data;
 
     if (conn->ssl->handshaked) {
-        conn->read->handler = &ngx_http_auth_ldap_read_handler;
-        ngx_http_auth_ldap_restore_handlers(conn);
-        ngx_http_auth_ldap_connection_established(c);
-        return;
+        // verify remote certificate
+        X509 *cert = SSL_get_peer_certificate(conn->ssl->connection);
+        long verified = SSL_get_verify_result(conn->ssl->connection);
+
+        if (cert && verified == X509_V_OK) { // everything fine
+          conn->read->handler = &ngx_http_auth_ldap_read_handler;
+          ngx_http_auth_ldap_restore_handlers(conn);
+          ngx_http_auth_ldap_connection_established(c);
+          return;
+        } else { // smells fishy
+          ngx_log_error(NGX_LOG_ERR, c->log, 0,
+            "http_auth_ldap: Remote side presented invalid SSL certificate: error %l, %s",
+            verified, X509_verify_cert_error_string(verified));
+          ngx_http_auth_ldap_close_connection(c);
+          return;
+        }
     }
 
     ngx_log_error(NGX_LOG_ERR, c->log, 0, "http_auth_ldap: SSL handshake failed");
@@ -1242,14 +1254,23 @@ ngx_http_auth_ldap_ssl_handshake(ngx_http_auth_ldap_connection_t *c)
     }
 
     c->log->action = "SSL handshaking to LDAP server";
+    ngx_connection_t *transport = c->conn.connection;
+
+    //int setcode = SSL_CTX_load_verify_locations(transport->ssl->connection->ctx, "file", "dir");
+    int setcode = SSL_CTX_set_default_verify_paths(transport->ssl->connection->ctx);
+    if (setcode != 1) {
+      ngx_log_error(NGX_LOG_ERR, c->log, 0,
+        "http_auth_ldap: SSL initialization failed. Could not set CA certificate location. "
+        "Error code: %lu", ERR_get_error());
+    }
 
-    rc = ngx_ssl_handshake(c->conn.connection);
+    rc = ngx_ssl_handshake(transport);
     if (rc == NGX_AGAIN) {
-        c->conn.connection->ssl->handler = &ngx_http_auth_ldap_ssl_handshake_handler;
+        transport->ssl->handler = &ngx_http_auth_ldap_ssl_handshake_handler;
         return;
     }
 
-    ngx_http_auth_ldap_ssl_handshake_handler(c->conn.connection);
+    ngx_http_auth_ldap_ssl_handshake_handler(transport);
     return;
 }
 #endif