1 files changed, 216 insertions, 0 deletions
diff --git a/src/lib-lda/mail-send.c b/src/lib-lda/mail-send.c
new file mode 100644
index 0000000..2027b0b
--- /dev/null
+++ b/src/lib-lda/mail-send.c
@@ -0,0 +1,216 @@
+/* Copyright (c) 2005-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "ioloop.h"
+#include "hostpid.h"
+#include "istream.h"
+#include "ostream.h"
+#include "str.h"
+#include "str-sanitize.h"
+#include "var-expand.h"
+#include "message-date.h"
+#include "message-size.h"
+#include "message-address.h"
+#include "istream-header-filter.h"
+#include "mail-storage.h"
+#include "mail-storage-settings.h"
+#include "iostream-ssl.h"
+#include "lda-settings.h"
+#include "mail-deliver.h"
+#include "smtp-address.h"
+#include "smtp-submit.h"
+#include "mail-send.h"
+
+#include <sys/wait.h>
+
+static const struct var_expand_table *
+get_var_expand_table(struct mail *mail,
+		     const struct smtp_address *recipient,
+		     const char *reason)
+{
+	const char *subject;
+	if (mail_get_first_header(mail, "Subject", &subject) <= 0)
+		subject = "";
+
+	const struct var_expand_table stack_tab[] = {
+		{ 'n', "\r\n", "crlf" },
+		{ 'r', reason, "reason" },
+		{ 's', str_sanitize(subject, 80), "subject" },
+		{ 't', smtp_address_encode(recipient), "to" },
+		{ '\0', NULL, NULL }
+	};
+	struct var_expand_table *tab;
+
+	tab = t_malloc_no0(sizeof(stack_tab));
+	memcpy(tab, stack_tab, sizeof(stack_tab));
+	return tab;
+}
+
+int mail_send_rejection(struct mail_deliver_context *ctx,
+			const struct smtp_address *recipient,
+			const char *reason)
+{
+	struct mail_user *user = ctx->rcpt_user;
+	struct ssl_iostream_settings ssl_set;
+	struct mail *mail = ctx->src_mail;
+	struct istream *input;
+	struct smtp_submit_input smtp_input;
+	struct smtp_submit *smtp_submit;
+	struct ostream *output;
+	const struct message_address *postmaster_addr;
+	const struct smtp_address *return_addr;
+	const char *hdr, *value, *msgid, *orig_msgid, *boundary, *error;
+	const struct var_expand_table *vtable;
+	string_t *str;
+	int ret;
+
+	if (mail_get_first_header(mail, "Message-ID", &orig_msgid) < 0)
+		orig_msgid = NULL;
+
+	if (mail_get_first_header(mail, "Auto-Submitted", &value) > 0 &&
+		strcasecmp(value, "no") != 0) {
+		i_info("msgid=%s: Auto-submitted message discarded: %s",
+			orig_msgid == NULL ? "" : str_sanitize(orig_msgid, 80),
+			str_sanitize(reason, 512));
+		return 0;
+	}
+
+	return_addr = mail_deliver_get_return_address(ctx);
+	if (smtp_address_isnull(return_addr)) {
+		i_info("msgid=%s: Return-Path missing, rejection reason: %s",
+			orig_msgid == NULL ? "" : str_sanitize(orig_msgid, 80),
+			str_sanitize(reason, 512));
+		return 0;
+	}
+
+	if (!mail_user_get_postmaster_address(user, &postmaster_addr, &error)) {
+		i_error("msgid=%s: Invalid postmaster_address - can't send rejection: %s",
+			orig_msgid == NULL ? "" : str_sanitize(orig_msgid, 80), error);
+		return -1;
+	}
+
+	e_debug(mail_event(mail), "Sending a rejection to <%s>: %s",
+		smtp_address_encode(return_addr),
+		str_sanitize(reason, 512));
+
+	vtable = get_var_expand_table(mail, recipient, reason);
+
+	mail_user_init_ssl_client_settings(user, &ssl_set);
+
+	i_zero(&smtp_input);
+	smtp_input.ssl = &ssl_set;
+	smtp_submit = smtp_submit_init_simple(&smtp_input, ctx->smtp_set, NULL);
+	smtp_submit_add_rcpt(smtp_submit, return_addr);
+	output = smtp_submit_send(smtp_submit);
+
+	msgid = mail_deliver_get_new_message_id(ctx);
+	boundary = t_strdup_printf("%s/%s", my_pid, user->set->hostname);
+
+	str = t_str_new(512);
+	str_printfa(str, "Message-ID: %s\r\n", msgid);
+	str_printfa(str, "Date: %s\r\n", message_date_create(ioloop_time));
+	str_append(str, "From: ");
+	message_address_write(str, postmaster_addr);
+	str_append(str, "\r\n");
+	str_printfa(str, "To: <%s>\r\n", smtp_address_encode(return_addr));
+	str_append(str, "MIME-Version: 1.0\r\n");
+	str_printfa(str, "Content-Type: "
+		"multipart/report; report-type=%s;\r\n"
+		"\tboundary=\"%s\"\r\n",
+		ctx->dsn ? "delivery-status" : "disposition-notification",
+		boundary);
+	str_append(str, "Subject: ");
+	if (var_expand(str, ctx->set->rejection_subject,
+		vtable, &error) <= 0) {
+		i_error("Failed to expand rejection_subject=%s: %s",
+			ctx->set->rejection_subject, error);
+	}
+	str_append(str, "\r\n");
+
+	str_append(str, "Auto-Submitted: auto-replied (rejected)\r\n");
+	str_append(str, "Precedence: bulk\r\n");
+	str_append(str, "\r\nThis is a MIME-encapsulated message\r\n\r\n");
+
+	/* human readable status report */
+	str_printfa(str, "--%s\r\n", boundary);
+	str_append(str, "Content-Type: text/plain; charset=utf-8\r\n");
+	str_append(str, "Content-Disposition: inline\r\n");
+	str_append(str, "Content-Transfer-Encoding: 8bit\r\n\r\n");
+
+	if (var_expand(str, ctx->set->rejection_reason,
+		vtable, &error) <= 0) {
+		i_error("Failed to expand rejection_reason=%s: %s",
+			ctx->set->rejection_reason, error);
+	}
+	str_append(str, "\r\n");
+
+	if (ctx->dsn) {
+		/* DSN status report: For LDA rejects. currently only used when
+		   user is out of quota */
+		str_printfa(str, "--%s\r\n"
+			"Content-Type: message/delivery-status\r\n\r\n",
+			boundary);
+		str_printfa(str, "Reporting-MTA: dns; %s\r\n", user->set->hostname);
+		if (mail_get_first_header(mail, "Original-Recipient", &hdr) > 0)
+			str_printfa(str, "Original-Recipient: rfc822; %s\r\n", hdr);
+		str_printfa(str, "Final-Recipient: rfc822; %s\r\n",
+			smtp_address_encode(recipient));
+		str_append(str, "Action: failed\r\n");
+		str_printfa(str, "Status: %s\r\n", ctx->mailbox_full ? "5.2.2" : "5.2.0");
+	} else {
+		/* MDN status report: For Sieve "reject" */
+		str_printfa(str, "--%s\r\n"
+			"Content-Type: message/disposition-notification\r\n\r\n",
+			boundary);
+		str_printfa(str, "Reporting-UA: %s; Dovecot Mail Delivery Agent\r\n",
+			user->set->hostname);
+		if (mail_get_first_header(mail, "Original-Recipient", &hdr) > 0)
+			str_printfa(str, "Original-Recipient: rfc822; %s\r\n", hdr);
+		str_printfa(str, "Final-Recipient: rfc822; %s\r\n",
+			smtp_address_encode(recipient));
+
+		if (orig_msgid != NULL)
+			str_printfa(str, "Original-Message-ID: %s\r\n", orig_msgid);
+		str_append(str, "Disposition: "
+			"automatic-action/MDN-sent-automatically; deleted\r\n");
+	}
+	str_append(str, "\r\n");
+
+	/* original message's headers */
+	str_printfa(str, "--%s\r\nContent-Type: message/rfc822\r\n\r\n", boundary);
+	o_stream_nsend(output, str_data(str), str_len(str));
+
+	if (mail_get_hdr_stream(mail, NULL, &input) == 0) {
+		/* Note: If you add more headers, they need to be sorted.
+		   We'll drop Content-Type because we're not including the message
+		   body, and having a multipart Content-Type may confuse some
+		   MIME parsers when they don't see the message boundaries. */
+		static const char *const exclude_headers[] = {
+			"Content-Type"
+		};
+
+		input = i_stream_create_header_filter(input,
+			HEADER_FILTER_EXCLUDE | HEADER_FILTER_NO_CR |
+			HEADER_FILTER_HIDE_BODY, exclude_headers,
+			N_ELEMENTS(exclude_headers),
+			*null_header_filter_callback, NULL);
+
+		o_stream_nsend_istream(output, input);
+		i_stream_unref(&input);
+	}
+
+	str_truncate(str, 0);
+	str_printfa(str, "\r\n\r\n--%s--\r\n", boundary);
+	o_stream_nsend(output, str_data(str), str_len(str));
+	if ((ret = smtp_submit_run(smtp_submit, &error)) < 0) {
+		i_error("msgid=%s: Temporarily failed to send rejection: %s",
+			orig_msgid == NULL ? "" : str_sanitize(orig_msgid, 80),
+			str_sanitize(error, 512));
+	} else if (ret == 0) {
+		i_info("msgid=%s: Permanently failed to send rejection: %s",
+			orig_msgid == NULL ? "" : str_sanitize(orig_msgid, 80),
+			str_sanitize(error, 512));
+	}
+	smtp_submit_deinit(&smtp_submit);
+	return ret < 0 ? -1 : 0;
+}