1 files changed, 59 insertions, 0 deletions
diff --git a/src/lib-sasl/mech-external.c b/src/lib-sasl/mech-external.c
new file mode 100644
index 0000000..7df94b4
--- /dev/null
+++ b/src/lib-sasl/mech-external.c
@@ -0,0 +1,59 @@
+/* Copyright (c) 2016-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "dsasl-client-private.h"
+
+struct external_dsasl_client {
+	struct dsasl_client client;
+	bool output_sent;
+};
+
+static int
+mech_external_input(struct dsasl_client *_client,
+		    const unsigned char *input ATTR_UNUSED, size_t input_len,
+		    const char **error_r)
+{
+	struct external_dsasl_client *client =
+		(struct external_dsasl_client *)_client;
+
+	if (!client->output_sent) {
+		if (input_len > 0) {
+			*error_r = "Server sent non-empty initial response";
+			return -1;
+		}
+	} else {
+		*error_r = "Server didn't finish authentication";
+		return -1;
+	}
+	return 0;
+}
+
+static int
+mech_external_output(struct dsasl_client *_client,
+		     const unsigned char **output_r, size_t *output_len_r,
+		     const char **error_r ATTR_UNUSED)
+{
+	struct external_dsasl_client *client =
+		(struct external_dsasl_client *)_client;
+	const char *username;
+
+	if (_client->set.authzid != NULL)
+		username = _client->set.authzid;
+	else if (_client->set.authid != NULL)
+		username = _client->set.authid;
+	else
+		username = "";
+
+	*output_r = (const void *)username;
+	*output_len_r = strlen(username);
+	client->output_sent = TRUE;
+	return 0;
+}
+
+const struct dsasl_client_mech dsasl_client_mech_external = {
+	.name = "EXTERNAL",
+	.struct_size = sizeof(struct external_dsasl_client),
+
+	.input = mech_external_input,
+	.output = mech_external_output
+};