Verify remote SSL certificate

ngx_http_auth_ldap_module.c

@@ -378,7 +378,7 @@ ngx_http_auth_ldap_ldap_server(ngx_conf_t *cf, ngx_command_t *dummy, void *conf)
             return NGX_CONF_ERROR;
         }
         server->connections = i;
-    } 
+    }
     else CONF_MSEC_VALUE(cf,value,server,connect_timeout)
     else CONF_MSEC_VALUE(cf,value,server,reconnect_timeout)
     else CONF_MSEC_VALUE(cf,value,server,bind_timeout)
@@ -1025,7 +1025,7 @@ ngx_http_auth_ldap_close_connection(ngx_http_auth_ldap_connection_t *c)
     c->rctx = NULL;
     if (c->state != STATE_DISCONNECTED) {
         c->state = STATE_DISCONNECTED;
-        ngx_add_timer(&c->reconnect_event, c->server->reconnect_timeout); 
+        ngx_add_timer(&c->reconnect_event, c->server->reconnect_timeout);
         ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http_auth_ldap: Connection scheduled for reconnection in %d ms", c->server->reconnect_timeout);
     }
 }
@@ -1205,7 +1205,7 @@ ngx_http_auth_ldap_connection_established(ngx_http_auth_ldap_connection_t *c)
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http_auth_ldap: ldap_sasl_bind() -> msgid=%d", c->msgid);
 
     c->state = STATE_INITIAL_BINDING;
-    ngx_add_timer(c->conn.connection->read, c->server->bind_timeout); 
+    ngx_add_timer(c->conn.connection->read, c->server->bind_timeout);
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http_auth_ldap: bind_timeout=%d", c->server->bind_timeout);
 }
 
@@ -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;
+        // verify remote certificate
-        ngx_http_auth_ldap_restore_handlers(conn);
+        X509 *cert = SSL_get_peer_certificate(conn->ssl->connection);
-        ngx_http_auth_ldap_connection_established(c);
+        long verified = SSL_get_verify_result(conn->ssl->connection);
-        return;
+
+        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;
 
-    rc = ngx_ssl_handshake(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(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
@@ -1450,7 +1471,7 @@ ngx_http_auth_ldap_connect(ngx_http_auth_ldap_connection_t *c)
     if (rc == NGX_ERROR || rc == NGX_BUSY || rc == NGX_DECLINED) {
         ngx_log_error(NGX_LOG_ERR, c->log, 0, "http_auth_ldap: Unable to connect to LDAP server \"%V\".",
             &addr->name);
-        ngx_add_timer(&c->reconnect_event, c->server->reconnect_timeout); 
+        ngx_add_timer(&c->reconnect_event, c->server->reconnect_timeout);
         return;
     }
 
@@ -1461,7 +1482,7 @@ ngx_http_auth_ldap_connect(ngx_http_auth_ldap_connection_t *c)
 #endif
     conn->write->handler = ngx_http_auth_ldap_connect_handler;
     conn->read->handler = ngx_http_auth_ldap_read_handler;
-    ngx_add_timer(conn->read, c->server->connect_timeout); 
+    ngx_add_timer(conn->read, c->server->connect_timeout);
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http_auth_ldap: connect_timeout=%d.", c->server->connect_timeout);
 
 
@@ -1631,7 +1652,7 @@ ngx_http_auth_ldap_authenticate(ngx_http_request_t *r, ngx_http_auth_ldap_ctx_t
 
     /*
      * If we are not starting up a request (ctx->phase != PHASE_START) and we actually already
-     * sent a request (ctx->iteration > 0) and didn't receive a reply yet (!ctx->replied) we 
+     * sent a request (ctx->iteration > 0) and didn't receive a reply yet (!ctx->replied) we
      * ask to be called again at a later time when we hopefully have received a reply.
      *
      * It is quite possible that we reach this if while not having sent a request yet (ctx->iteration == 0) -
@@ -1651,7 +1672,7 @@ ngx_http_auth_ldap_authenticate(ngx_http_request_t *r, ngx_http_auth_ldap_ctx_t
                 ctx->server = ((ngx_http_auth_ldap_server_t **) conf->servers->elts)[ctx->server_index];
                 ctx->outcome = OUTCOME_UNCERTAIN;
 
-                ngx_add_timer(r->connection->write, ctx->server->request_timeout); 
+                ngx_add_timer(r->connection->write, ctx->server->request_timeout);
                 ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http_auth_ldap: request_timeout=%d",ctx->server->request_timeout);
 
 
@@ -2013,7 +2034,7 @@ ngx_http_auth_ldap_check_bind(ngx_http_request_t *r, ngx_http_auth_ldap_ctx_t *c
             ctx->c->msgid);
         ctx->c->state = STATE_BINDING;
         ctx->iteration++;
-        
+
         return NGX_AGAIN;
     }