login-common: Ensure we get username from certificate

diff --git a/src/login-common/sasl-server.c b/src/login-common/sasl-server.c
index dedfb5b8f9278fa2c699bbbd7c1f5adde970797b..ea14c0b6e82cff7650b3c78963c58909f6ef60e6 100644 (file)
--- a/src/login-common/sasl-server.c
+++ b/src/login-common/sasl-server.c
@@ -338,6 +338,43 @@ authenticate_callback(struct auth_client_request *request,
        }
 }
 
+static bool get_cert_username(struct client *client, const char **username_r,
+                             const char **error_r)
+{
+       /* this was proxied connection, so we use the name here */
+       if (client->client_cert_common_name != NULL) {
+               *username_r = client->client_cert_common_name;
+               return TRUE;
+       }
+
+       /* no SSL */
+       if (client->ssl_iostream == NULL) {
+               *username_r = NULL;
+               return TRUE;
+       }
+
+       /* no client certificate */
+       if (!ssl_iostream_has_valid_client_cert(client->ssl_iostream)) {
+               *username_r = NULL;
+               return TRUE;
+       }
+
+       /* get peer name */
+       const char *username = ssl_iostream_get_peer_name(client->ssl_iostream);
+
+       /* if we wanted peer name, but it was not there, fail */
+       if (client->set->auth_ssl_username_from_cert &&
+           (username == NULL || *username == '\0')) {
+               if (client->set->auth_ssl_require_client_cert) {
+                       *error_r = "Missing username in certificate";
+                       return FALSE;
+               }
+       }
+
+       *username_r = username;
+       return TRUE;
+}
+
 void sasl_server_auth_begin(struct client *client,
                            const char *service, const char *mech_name,
                            const char *initial_resp_base64,
@@ -345,6 +382,7 @@ void sasl_server_auth_begin(struct client *client,
 {
        struct auth_request_info info;
        const struct auth_mech_desc *mech;
+       const char *error;
 
        i_assert(auth_client_is_connected(auth_client));
 
@@ -376,9 +414,17 @@ void sasl_server_auth_begin(struct client *client,
        info.mech = mech->name;
        info.service = service;
        info.session_id = client_get_session_id(client);
-       if (client->client_cert_common_name != NULL)
-               info.cert_username = client->client_cert_common_name;
-       else if (client->ssl_iostream != NULL) {
+
+       if (!get_cert_username(client, &info.cert_username, &error)) {
+               client_log_err(client, t_strdup_printf("Cannot get username "
+                                                      "from certificate: %s", error));
+               sasl_server_auth_failed(client,
+                       "Unable to validate certificate",
+                       AUTH_CLIENT_FAIL_CODE_AUTHZFAILED);
+               return;
+       }
+
+       if (client->ssl_iostream != NULL) {
                info.cert_username = ssl_iostream_get_peer_name(client->ssl_iostream);
                info.ssl_cipher = ssl_iostream_get_cipher(client->ssl_iostream,
                                                         &info.ssl_cipher_bits);