1 files changed, 243 insertions, 0 deletions
diff --git a/src/lib-smtp/smtp-server-cmd-rcpt.c b/src/lib-smtp/smtp-server-cmd-rcpt.c
new file mode 100644
index 0000000..85e9a93
--- /dev/null
+++ b/src/lib-smtp/smtp-server-cmd-rcpt.c
@@ -0,0 +1,243 @@
+/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "str.h"
+#include "array.h"
+#include "smtp-parser.h"
+#include "smtp-address.h"
+#include "smtp-reply.h"
+#include "smtp-syntax.h"
+
+#include "smtp-server-private.h"
+
+/* RCPT command */
+
+struct smtp_server_cmd_rcpt {
+	struct smtp_server_recipient *rcpt;
+};
+
+static void
+cmd_rcpt_destroy(struct smtp_server_cmd_ctx *cmd ATTR_UNUSED,
+		 struct smtp_server_cmd_rcpt *data)
+{
+	smtp_server_recipient_destroy(&data->rcpt);
+}
+
+static bool
+cmd_rcpt_check_state(struct smtp_server_cmd_ctx *cmd, bool next_to_reply)
+{
+	struct smtp_server_connection *conn = cmd->conn;
+	struct smtp_server_command *command = cmd->cmd;
+	struct smtp_server_transaction *trans = conn->state.trans;
+
+	if (smtp_server_command_is_replied(command) &&
+	    !smtp_server_command_replied_success(command) &&
+	    !smtp_server_command_reply_is_forwarded(command))
+		return FALSE;
+
+	if (trans == NULL &&
+	    (conn->state.pending_mail_cmds == 0 || next_to_reply)) {
+		smtp_server_reply(cmd,
+			503, "5.5.0", "MAIL needed first");
+		return FALSE;
+	}
+	if (conn->set.max_recipients > 0 && trans != NULL &&
+		smtp_server_transaction_rcpt_count(trans) >=
+			conn->set.max_recipients) {
+		smtp_server_reply(cmd,
+			451, "4.5.3", "Too many recipients");
+		return FALSE;
+	}
+
+	return TRUE;
+}
+
+static void
+cmd_rcpt_completed(struct smtp_server_cmd_ctx *cmd,
+		   struct smtp_server_cmd_rcpt *data)
+{
+	struct smtp_server_connection *conn = cmd->conn;
+	struct smtp_server_command *command = cmd->cmd;
+	struct smtp_server_recipient *rcpt = data->rcpt;
+
+	i_assert(conn->state.pending_rcpt_cmds > 0);
+	conn->state.pending_rcpt_cmds--;
+
+	i_assert(smtp_server_command_is_replied(command));
+	i_assert(conn->state.state == SMTP_SERVER_STATE_RCPT_TO ||
+		 !smtp_server_command_replied_success(command));
+
+	if (!smtp_server_command_replied_success(command)) {
+		/* Failure */
+		conn->state.denied_rcpt_cmds++;
+		smtp_server_recipient_denied(
+			rcpt, smtp_server_command_get_reply(cmd->cmd, 0));
+		return;
+	}
+
+	/* Success */
+	data->rcpt = NULL; /* clear to prevent destruction */
+	(void)smtp_server_recipient_approved(&rcpt);
+}
+
+static void
+cmd_rcpt_recheck(struct smtp_server_cmd_ctx *cmd,
+		 struct smtp_server_cmd_rcpt *data ATTR_UNUSED)
+{
+	struct smtp_server_connection *conn = cmd->conn;
+
+	/* All preceeding commands have finished and now the transaction state
+	   is clear. This provides the opportunity to re-check the transaction
+	   state and abort the pending proxied mail command if it is bound to
+	   fail */
+	if (!cmd_rcpt_check_state(cmd, TRUE))
+		return;
+
+	/* Advance state */
+	smtp_server_connection_set_state(conn, SMTP_SERVER_STATE_RCPT_TO,
+					 smtp_address_encode(data->rcpt->path));
+}
+
+void smtp_server_cmd_rcpt(struct smtp_server_cmd_ctx *cmd,
+			  const char *params)
+{
+	struct smtp_server_connection *conn = cmd->conn;
+	const struct smtp_server_settings *set = &conn->set;
+	enum smtp_capability caps = set->capabilities;
+	const struct smtp_server_callbacks *callbacks = conn->callbacks;
+	struct smtp_server_command *command = cmd->cmd;
+	struct smtp_server_cmd_rcpt *rcpt_data;
+	struct smtp_server_recipient *rcpt;
+	enum smtp_address_parse_flags path_parse_flags;
+	enum smtp_param_rcpt_parse_flags param_parse_flags;
+	const char *const *param_extensions = NULL;
+	struct smtp_address *path;
+	struct smtp_params_rcpt rcpt_params;
+	enum smtp_param_parse_error pperror;
+	const char *error;
+	int ret;
+
+	/* rcpt         = "RCPT TO:" ( "<Postmaster@" Domain ">" /
+	      "<Postmaster>" / Forward-path ) [SP Rcpt-parameters] CRLF
+	   Forward-path = Path
+	 */
+
+	/* Check transaction state as far as possible */
+	if (!cmd_rcpt_check_state(cmd, FALSE))
+		return;
+
+	/* ( "<Postmaster@" Domain ">" / "<Postmaster>" / Forward-path ) */
+	if (params == NULL || strncasecmp(params, "TO:", 3) != 0) {
+		smtp_server_reply(cmd,
+			501, "5.5.4", "Invalid parameters");
+		return;
+	}
+	if (params[3] != ' ' && params[3] != '\t') {
+		params += 3;
+	} else if ((set->workarounds &
+		    SMTP_SERVER_WORKAROUND_WHITESPACE_BEFORE_PATH) != 0) {
+		params += 3;
+		while (*params == ' ' || *params == '\t')
+			params++;
+	} else {
+		smtp_server_reply(cmd, 501, "5.5.4",
+				  "Invalid TO: "
+				  "Unexpected whitespace before path");
+		return;
+	}
+	path_parse_flags = SMTP_ADDRESS_PARSE_FLAG_ALLOW_LOCALPART;
+	if ((set->workarounds & SMTP_SERVER_WORKAROUND_MAILBOX_FOR_PATH) != 0)
+		path_parse_flags |= SMTP_ADDRESS_PARSE_FLAG_BRACKETS_OPTIONAL;
+	if (smtp_address_parse_path_full(pool_datastack_create(), params,
+					 path_parse_flags, &path, &error,
+					 &params) < 0) {
+		smtp_server_reply(cmd,
+			501, "5.5.4", "Invalid TO: %s", error);
+		return;
+	}
+	if (*params == ' ')
+		params++;
+	else if (*params != '\0') {
+		smtp_server_reply(cmd, 501, "5.5.4",
+			"Invalid TO: Invalid character in path");
+		return;
+	}
+	if (path->domain == NULL && !conn->set.rcpt_domain_optional &&
+		strcasecmp(path->localpart, "postmaster") != 0) {
+		smtp_server_reply(cmd,
+			501, "5.5.4", "Invalid TO: Missing domain");
+		return;
+	}
+
+	/* [SP Rcpt-parameters] */
+	param_parse_flags = 0;
+	if (conn->set.rcpt_domain_optional)
+		param_parse_flags |= SMTP_PARAM_RCPT_FLAG_ORCPT_ALLOW_LOCALPART;
+	if (array_is_created(&conn->rcpt_param_extensions))
+		param_extensions = array_front(&conn->rcpt_param_extensions);
+	if (smtp_params_rcpt_parse(pool_datastack_create(), params,
+				   param_parse_flags, caps, param_extensions,
+				   &rcpt_params, &pperror, &error) < 0) {
+		switch (pperror) {
+		case SMTP_PARAM_PARSE_ERROR_BAD_SYNTAX:
+			smtp_server_reply(cmd,
+				501, "5.5.4", "%s", error);
+			break;
+		case SMTP_PARAM_PARSE_ERROR_NOT_SUPPORTED:
+			smtp_server_reply(cmd,
+				555, "5.5.4", "%s", error);
+			break;
+		default:
+			i_unreached();
+		}
+		return;
+	}
+
+	rcpt = smtp_server_recipient_create(cmd, path, &rcpt_params);
+
+	rcpt_data = p_new(cmd->pool, struct smtp_server_cmd_rcpt, 1);
+	rcpt_data->rcpt = rcpt;
+	command->data = rcpt_data;
+
+	smtp_server_command_add_hook(command, SMTP_SERVER_COMMAND_HOOK_NEXT,
+				     cmd_rcpt_recheck, rcpt_data);
+	smtp_server_command_add_hook(command, SMTP_SERVER_COMMAND_HOOK_COMPLETED,
+				     cmd_rcpt_completed, rcpt_data);
+	smtp_server_command_add_hook(command, SMTP_SERVER_COMMAND_HOOK_DESTROY,
+				     cmd_rcpt_destroy, rcpt_data);
+
+	conn->state.pending_rcpt_cmds++;
+
+	smtp_server_command_ref(command);
+	i_assert(callbacks != NULL && callbacks->conn_cmd_rcpt != NULL);
+
+	struct event_reason *reason =
+		smtp_server_connection_reason_begin(conn, "cmd_rcpt");
+	ret = callbacks->conn_cmd_rcpt(conn->context, cmd, rcpt);
+	event_reason_end(&reason);
+	if (ret <= 0) {
+		i_assert(ret == 0 || smtp_server_command_is_replied(command));
+		/* Command is waiting for external event or it failed */
+		smtp_server_command_unref(&command);
+		return;
+	}
+	if (!smtp_server_command_is_replied(command)) {
+		/* Set generic RCPT success reply if none is provided */
+		smtp_server_cmd_rcpt_reply_success(cmd);
+	}
+	smtp_server_command_unref(&command);
+}
+
+bool smtp_server_command_is_rcpt(struct smtp_server_cmd_ctx *cmd)
+{
+	return (cmd->cmd->reg->func == smtp_server_cmd_rcpt);
+}
+
+void smtp_server_cmd_rcpt_reply_success(struct smtp_server_cmd_ctx *cmd)
+{
+	struct smtp_server_cmd_rcpt *rcpt_data = cmd->cmd->data;
+
+	i_assert(smtp_server_command_is_rcpt(cmd));
+
+	smtp_server_recipient_reply(rcpt_data->rcpt, 250, "2.1.5", "OK");
+}