1 files changed, 615 insertions, 0 deletions

diff --git a/src/submission/submission-commands.c b/src/submission/submission-commands.c
new file mode 100644
index 0000000..8f6fbfb
--- /dev/null
+++ b/src/submission/submission-commands.c
@@ -0,0 +1,615 @@
+/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */
+
+#include "submission-common.h"
+#include "str.h"
+#include "istream.h"
+#include "istream-concat.h"
+#include "istream-seekable.h"
+#include "mail-storage.h"
+#include "imap-url.h"
+#include "imap-msgpart.h"
+#include "imap-msgpart-url.h"
+#include "imap-urlauth.h"
+#include "imap-urlauth-fetch.h"
+
+#include "submission-recipient.h"
+#include "submission-commands.h"
+#include "submission-backend-relay.h"
+
+/*
+ * EHLO, HELO commands
+ */
+
+static void
+submission_helo_reply_add_extra(struct client *client,
+				struct smtp_server_reply *reply)
+{
+	const struct client_extra_capability *cap;
+
+	if (!array_is_created(&client->extra_capabilities))
+		return;
+
+	array_foreach(&client->extra_capabilities, cap) {
+		if (cap->params == NULL) {
+			smtp_server_reply_ehlo_add(reply, cap->capability);
+		} else {
+			smtp_server_reply_ehlo_add_param(reply, cap->capability,
+							 "%s", cap->params);
+		}
+	}
+}
+
+void submission_helo_reply_submit(struct smtp_server_cmd_ctx *cmd,
+				  struct smtp_server_cmd_helo *data)
+{
+	struct client *client = smtp_server_connection_get_context(cmd->conn);
+	enum smtp_capability backend_caps = client->backend_capabilities;
+	struct smtp_server_reply *reply;
+	uoff_t cap_size;
+
+	reply = smtp_server_reply_create_ehlo(cmd->cmd);
+	if (!data->helo.old_smtp) {
+		string_t *burl_params = t_str_new(256);
+
+		str_append(burl_params, "imap");
+		if (*client->set->imap_urlauth_host == '\0' ||
+			strcmp(client->set->imap_urlauth_host,
+			       URL_HOST_ALLOW_ANY) == 0) {
+			str_printfa(burl_params, " imap://%s",
+				    client->set->hostname);
+		} else {
+			str_printfa(burl_params, " imap://%s",
+				    client->set->imap_urlauth_host);
+		}
+		if (client->set->imap_urlauth_port != 143) {
+			str_printfa(burl_params, ":%u",
+				    client->set->imap_urlauth_port);
+		}
+
+		if ((backend_caps & SMTP_CAPABILITY_8BITMIME) != 0)
+			smtp_server_reply_ehlo_add(reply, "8BITMIME");
+		smtp_server_reply_ehlo_add(reply, "AUTH");
+		if ((backend_caps & SMTP_CAPABILITY_BINARYMIME) != 0 &&
+		    (backend_caps & SMTP_CAPABILITY_CHUNKING) != 0)
+			smtp_server_reply_ehlo_add(reply, "BINARYMIME");
+		smtp_server_reply_ehlo_add_param(reply,
+			"BURL", "%s", str_c(burl_params));
+		smtp_server_reply_ehlo_add(reply, "CHUNKING");
+		if ((backend_caps & SMTP_CAPABILITY_DSN) != 0)
+			smtp_server_reply_ehlo_add(reply, "DSN");
+		smtp_server_reply_ehlo_add(reply,
+			"ENHANCEDSTATUSCODES");
+		smtp_server_reply_ehlo_add(reply,
+			"PIPELINING");
+
+		cap_size = client_get_max_mail_size(client);
+		if (cap_size > 0) {
+			smtp_server_reply_ehlo_add_param(reply,
+				"SIZE", "%"PRIuUOFF_T, cap_size);
+		} else {
+			smtp_server_reply_ehlo_add(reply, "SIZE");
+		}
+		if ((backend_caps & SMTP_CAPABILITY_VRFY) != 0)
+			smtp_server_reply_ehlo_add(reply, "VRFY");
+
+		submission_helo_reply_add_extra(client, reply);
+	}
+	smtp_server_reply_submit(reply);
+}
+
+int cmd_helo(void *conn_ctx, struct smtp_server_cmd_ctx *cmd,
+	     struct smtp_server_cmd_helo *data)
+{
+	struct client *client = conn_ctx;
+
+	if (!data->first ||
+	    smtp_server_connection_get_state(client->conn, NULL)
+		>= SMTP_SERVER_STATE_READY)
+		return client->v.cmd_helo(client, cmd, data);
+
+	/* respond right away */
+	submission_helo_reply_submit(cmd, data);
+	return 1;
+}
+
+int client_default_cmd_helo(struct client *client,
+			    struct smtp_server_cmd_ctx *cmd,
+			    struct smtp_server_cmd_helo *data)
+{
+	return submission_backend_cmd_helo(client->backend_default, cmd, data);
+}
+
+
+/*
+ * MAIL command
+ */
+
+int cmd_mail(void *conn_ctx, struct smtp_server_cmd_ctx *cmd,
+	     struct smtp_server_cmd_mail *data)
+{
+	struct client *client = conn_ctx;
+
+	client->state.backend = client->backend_default;
+
+	return client->v.cmd_mail(client, cmd, data);
+}
+
+int client_default_cmd_mail(struct client *client,
+			    struct smtp_server_cmd_ctx *cmd,
+			    struct smtp_server_cmd_mail *data)
+{
+	if (client->user->anonymous && !client->state.anonymous_allowed) {
+		/* NOTE: may need to allow anonymous BURL access in the future,
+		   but while that is not supported, deny all anonymous access
+		   explicitly. */
+		smtp_server_reply(cmd, 554, "5.7.1",
+				  "Access denied (anonymous user)");
+		return -1;
+	}
+
+	return submission_backend_cmd_mail(client->state.backend, cmd, data);
+}
+
+/*
+ * RCPT command
+ */
+
+int cmd_rcpt(void *conn_ctx, struct smtp_server_cmd_ctx *cmd,
+	     struct smtp_server_recipient *rcpt)
+{
+	struct client *client = conn_ctx;
+	struct submission_recipient *srcpt;
+
+	srcpt = submission_recipient_create(client, rcpt);
+
+	return client->v.cmd_rcpt(client, cmd, srcpt);
+}
+
+int client_default_cmd_rcpt(struct client *client ATTR_UNUSED,
+			    struct smtp_server_cmd_ctx *cmd,
+			    struct submission_recipient *srcpt)
+{
+	if (client->user->anonymous && !srcpt->anonymous_allowed) {
+		/* NOTE: may need to allow anonymous BURL access in the future,
+		   but while that is not supported, deny all anonymous access
+		   explicitly. */
+		smtp_server_recipient_reply(
+			srcpt->rcpt, 554, "5.7.1",
+			"Access denied (anonymous user)");
+		return -1;
+	}
+
+	return submission_backend_cmd_rcpt(srcpt->backend, cmd, srcpt);
+}
+
+/*
+ * RSET command
+ */
+
+int cmd_rset(void *conn_ctx, struct smtp_server_cmd_ctx *cmd)
+{
+	struct client *client = conn_ctx;
+
+	return client->v.cmd_rset(client, cmd);
+}
+
+int client_default_cmd_rset(struct client *client,
+			    struct smtp_server_cmd_ctx *cmd)
+{
+	struct submission_backend *backend = client->state.backend;
+
+	if (backend == NULL)
+		backend = client->backend_default;
+
+	/* all backends will also be notified through trans_free(), but that
+	   doesn't allow changing the RSET command response. */
+	return submission_backend_cmd_rset(backend, cmd);
+}
+
+/*
+ * DATA/BDAT commands
+ */
+
+int cmd_data_continue(void *conn_ctx, struct smtp_server_cmd_ctx *cmd,
+		      struct smtp_server_transaction *trans)
+{
+	struct client *client = conn_ctx;
+	struct istream *data_input = client->state.data_input;
+	uoff_t data_size;
+	struct istream *inputs[3];
+	string_t *added_headers;
+	const unsigned char *data;
+	size_t size;
+	int ret;
+
+	while ((ret = i_stream_read_more(data_input, &data, &size)) > 0) {
+		i_stream_skip(data_input, size);
+		if (!smtp_server_cmd_data_check_size(cmd))
+			return -1;
+	}
+
+	if (ret == 0)
+		return 0;
+	if (ret < 0 && data_input->stream_errno != 0)
+		return -1;
+
+	/* Done reading DATA stream; remove it from state and continue with
+	   local variable. */
+	client->state.data_input = NULL;
+
+	/* Current data stream position is the data size */
+	client->state.data_size = data_input->v_offset;
+
+	/* prepend our own headers */
+	added_headers = t_str_new(200);
+	smtp_server_transaction_write_trace_record(
+		added_headers, trans, SMTP_SERVER_TRACE_RCPT_TO_ADDRESS_FINAL);
+
+	i_stream_seek(data_input, 0);
+	inputs[0] = i_stream_create_copy_from_data(
+		str_data(added_headers), str_len(added_headers));
+	inputs[1] = data_input;
+	inputs[2] = NULL;
+
+	data_input = i_stream_create_concat(inputs);
+	i_stream_set_name(data_input, "<submission DATA>");
+	data_size = client->state.data_size + str_len(added_headers);
+
+	i_stream_unref(&inputs[0]);
+	i_stream_unref(&inputs[1]);
+
+	ret = client->v.cmd_data(client, cmd, trans, data_input, data_size);
+
+	i_stream_unref(&data_input);
+	return ret;
+}
+
+int cmd_data_begin(void *conn_ctx,
+		   struct smtp_server_cmd_ctx *cmd ATTR_UNUSED,
+		   struct smtp_server_transaction *trans ATTR_UNUSED,
+		   struct istream *data_input)
+{
+	struct client *client = conn_ctx;
+	struct istream *inputs[2];
+	string_t *path;
+
+	if (client->user->anonymous && !client->state.anonymous_allowed) {
+		smtp_server_reply(cmd, 554, "5.7.1",
+				  "Access denied (anonymous user)");
+		return -1;
+	}
+
+	inputs[0] = data_input;
+	inputs[1] = NULL;
+
+	path = t_str_new(256);
+	mail_user_set_get_temp_prefix(path, client->user->set);
+	client->state.data_input = i_stream_create_seekable_path(inputs,
+		SUBMISSION_MAIL_DATA_MAX_INMEMORY_SIZE, str_c(path));
+	return 0;
+}
+
+int client_default_cmd_data(struct client *client,
+			    struct smtp_server_cmd_ctx *cmd,
+			    struct smtp_server_transaction *trans,
+			    struct istream *data_input, uoff_t data_size)
+{
+	return submission_backends_cmd_data(client, cmd, trans,
+					    data_input, data_size);
+}
+
+/*
+ * BURL command
+ */
+
+/* FIXME: RFC 4468
+   If the  URL argument to BURL refers to binary data, then the submit server
+   MAY refuse the command or down convert as described in Binary SMTP.
+ */
+
+struct cmd_burl_context {
+	struct client *client;
+	struct smtp_server_cmd_ctx *cmd;
+
+	struct imap_urlauth_fetch *urlauth_fetch;
+	struct imap_msgpart_url *url_fetch;
+
+	bool chunk_last:1;
+};
+
+static void
+cmd_burl_destroy(struct smtp_server_cmd_ctx *cmd ATTR_UNUSED,
+		 struct cmd_burl_context *burl_cmd)
+{
+	if (burl_cmd->urlauth_fetch != NULL)
+		imap_urlauth_fetch_deinit(&burl_cmd->urlauth_fetch);
+	if (burl_cmd->url_fetch != NULL)
+		imap_msgpart_url_free(&burl_cmd->url_fetch);
+}
+
+static int
+cmd_burl_fetch_cb(struct imap_urlauth_fetch_reply *reply,
+		  bool last, void *context)
+{
+	struct cmd_burl_context *burl_cmd = context;
+	struct smtp_server_cmd_ctx *cmd = burl_cmd->cmd;
+	int ret;
+
+	i_assert(last);
+
+	if (reply == NULL) {
+		/* fatal failure */
+		// FIXME: make this an internal error
+		smtp_server_reply(cmd, 554, "5.6.6",
+			"IMAP URLAUTH resolution failed");
+		return -1;
+	}
+	if (!reply->succeeded) {
+		/* URL fetch failed */
+		if (reply->error != NULL) {
+			smtp_server_reply(cmd, 554, "5.6.6",
+				"IMAP URLAUTH resolution failed: %s",
+				reply->error);
+		} else {
+			smtp_server_reply(cmd, 554, "5.6.6",
+				"IMAP URLAUTH resolution failed");
+		}
+		return 1;
+	}
+
+	/* URL fetch succeeded */
+	ret = smtp_server_connection_data_chunk_add(cmd,
+		reply->input, reply->size, burl_cmd->chunk_last, FALSE);
+	if (ret < 0)
+		return -1;
+
+	/* Command is likely not yet complete at this point, so return 0 */
+	return 0;
+}
+
+static int
+cmd_burl_fetch_trusted(struct cmd_burl_context *burl_cmd,
+		       struct imap_url *imap_url)
+{
+	struct smtp_server_cmd_ctx *cmd = burl_cmd->cmd;
+	struct client *client = burl_cmd->client;
+	const char *host_name = client->set->imap_urlauth_host;
+	in_port_t host_port = client->set->imap_urlauth_port;
+	struct imap_msgpart_open_result result;
+	const char *error;
+
+	/* validate host */
+	if (imap_url->host.name == NULL ||
+		(strcmp(host_name, URL_HOST_ALLOW_ANY) != 0 &&
+		  strcmp(imap_url->host.name, host_name) != 0)) {
+		smtp_server_reply(cmd, 554, "5.6.6",
+			"IMAP URL resolution failed: "
+			"Inappropriate or missing host name");
+		return -1;
+	}
+
+	/* validate port */
+	if ((imap_url->port == 0 && host_port != 143) ||
+		(imap_url->port != 0 && host_port != imap_url->port)) {
+		smtp_server_reply(cmd, 554, "5.6.6",
+			"IMAP URL resolution failed: "
+			"Inappropriate server port");
+		return -1;
+	}
+
+	/* retrieve URL */
+	if (imap_msgpart_url_create
+		(client->user, imap_url, &burl_cmd->url_fetch, &error) < 0) {
+		smtp_server_reply(cmd, 554, "5.6.6",
+			"IMAP URL resolution failed: %s", error);
+		return -1;
+	}
+	if (imap_msgpart_url_read_part(burl_cmd->url_fetch,
+		&result, &error) <= 0) {
+		smtp_server_reply(cmd, 554, "5.6.6",
+			"IMAP URL resolution failed: %s", error);
+		return -1;
+	}
+
+	return smtp_server_connection_data_chunk_add(cmd,
+		result.input, result.size, burl_cmd->chunk_last, FALSE);
+}
+
+static int
+cmd_burl_fetch(struct cmd_burl_context *burl_cmd, const char *url,
+	       struct imap_url *imap_url)
+{
+	struct smtp_server_cmd_ctx *cmd = burl_cmd->cmd;
+	struct client *client = burl_cmd->client;
+
+	if (client->urlauth_ctx == NULL) {
+		/* RFC5248, Section 2.4:
+
+		   554 5.7.14 Trust relationship required
+
+		   The submission server requires a configured trust
+		   relationship with a third-party server in order to access
+		   the message content. This value replaces the prior use of
+		   X.7.8 for this error condition, thereby updating [RFC4468].
+		 */
+		smtp_server_reply(cmd, 554, "5.7.14",
+			"No IMAP URLAUTH access available");
+		return -1;
+	}
+
+	/* urlauth */
+	burl_cmd->urlauth_fetch =
+		imap_urlauth_fetch_init(client->urlauth_ctx,
+					cmd_burl_fetch_cb, burl_cmd);
+	if (imap_urlauth_fetch_url_parsed(burl_cmd->urlauth_fetch,
+		url, imap_url, IMAP_URLAUTH_FETCH_FLAG_BODY) == 0) {
+		/* wait for URL fetch */
+		return 0;
+	}
+	return 1;
+}
+
+void cmd_burl(struct smtp_server_cmd_ctx *cmd, const char *params)
+{
+	struct smtp_server_connection *conn = cmd->conn;
+	struct client *client = smtp_server_connection_get_context(conn);
+	struct cmd_burl_context *burl_cmd;
+	const char *const *argv;
+	enum imap_url_parse_flags url_parse_flags =
+		IMAP_URL_PARSE_ALLOW_URLAUTH;
+	struct imap_url *imap_url;
+	const char *url, *error;
+	bool chunk_last = FALSE;
+	int ret = 1;
+
+	smtp_server_connection_data_chunk_init(cmd);
+
+	/* burl-cmd   = "BURL" SP absolute-URI [SP end-marker] CRLF
+	   end-marker = "LAST"
+	 */
+	argv = t_strsplit(params, " ");
+	url = argv[0];
+	if (url == NULL) {
+		smtp_server_reply(cmd, 501, "5.5.4",
+			"Missing chunk URL parameter");
+		ret = -1;
+	} else if (imap_url_parse(url, NULL, url_parse_flags,
+				  &imap_url, &error) < 0) {
+		smtp_server_reply(cmd, 501, "5.5.4",
+			"Invalid chunk URL: %s", error);
+		ret = -1;
+	} else if (argv[1] != NULL) {
+		if (strcasecmp(argv[1], "LAST") != 0) {
+			smtp_server_reply(cmd, 501, "5.5.4",
+				"Invalid end marker parameter");
+			ret = -1;
+		} else if (argv[2] != NULL) {
+			smtp_server_reply(cmd, 501, "5.5.4",
+				"Invalid parameters");
+			ret = -1;
+		} else {
+			chunk_last = TRUE;
+		}
+	}
+
+	if (ret < 0 || !smtp_server_connection_data_check_state(cmd))
+		return;
+
+	if (client->user->anonymous) {
+		smtp_server_reply(cmd, 554, "5.7.1",
+				  "Access denied (anonymous user)");
+		return;
+	}
+
+	burl_cmd = p_new(cmd->pool, struct cmd_burl_context, 1);
+	burl_cmd->client = client;
+	burl_cmd->cmd = cmd;
+	burl_cmd->chunk_last = chunk_last;
+
+	smtp_server_command_add_hook(cmd->cmd, SMTP_SERVER_COMMAND_HOOK_DESTROY,
+				     cmd_burl_destroy, burl_cmd);
+
+	if (imap_url->uauth_rumpurl == NULL) {
+		/* direct local url */
+		ret = cmd_burl_fetch_trusted(burl_cmd, imap_url);
+	} else {
+		ret = cmd_burl_fetch(burl_cmd, url, imap_url);
+	}
+
+	if (ret == 0 && chunk_last)
+		smtp_server_command_input_lock(cmd);
+}
+
+/*
+ * VRFY command
+ */
+
+int cmd_vrfy(void *conn_ctx, struct smtp_server_cmd_ctx *cmd,
+	     const char *param)
+{
+	struct client *client = conn_ctx;
+
+	if (client->user->anonymous) {
+		smtp_server_reply(cmd, 550, "5.7.1",
+				  "Access denied (anonymous user)");
+		return -1;
+	}
+
+	return client->v.cmd_vrfy(client, cmd, param);
+}
+
+int client_default_cmd_vrfy(struct client *client,
+			    struct smtp_server_cmd_ctx *cmd, const char *param)
+{
+	return submission_backend_cmd_vrfy(client->backend_default, cmd, param);
+}
+
+/*
+ * NOOP command
+ */
+
+int cmd_noop(void *conn_ctx, struct smtp_server_cmd_ctx *cmd)
+{
+	struct client *client = conn_ctx;
+
+	return client->v.cmd_noop(client, cmd);
+}
+
+int client_default_cmd_noop(struct client *client,
+			    struct smtp_server_cmd_ctx *cmd)
+{
+	return submission_backend_cmd_noop(client->backend_default, cmd);
+}
+
+/*
+ * QUIT command
+ */
+
+struct cmd_quit_context {
+	struct client *client;
+
+	struct smtp_server_cmd_ctx *cmd;
+};
+
+static void cmd_quit_finish(struct cmd_quit_context *quit_cmd)
+{
+	struct client *client = quit_cmd->client;
+	struct smtp_server_cmd_ctx *cmd = quit_cmd->cmd;
+
+	timeout_remove(&client->to_quit);
+	smtp_server_reply_quit(cmd);
+}
+
+static void
+cmd_quit_next(struct smtp_server_cmd_ctx *cmd ATTR_UNUSED,
+	      struct cmd_quit_context *quit_cmd)
+{
+	struct client *client = quit_cmd->client;
+
+	/* give backend a brief interval to generate a quit reply */
+	client->to_quit = timeout_add(SUBMISSION_MAX_WAIT_QUIT_REPLY_MSECS,
+				      cmd_quit_finish, quit_cmd);
+}
+
+int cmd_quit(void *conn_ctx, struct smtp_server_cmd_ctx *cmd)
+{
+	struct client *client = conn_ctx;
+	struct cmd_quit_context *quit_cmd;
+
+	quit_cmd = p_new(cmd->pool, struct cmd_quit_context, 1);
+	quit_cmd->client = client;
+	quit_cmd->cmd = cmd;
+
+	smtp_server_command_add_hook(cmd->cmd, SMTP_SERVER_COMMAND_HOOK_NEXT,
+				     cmd_quit_next, quit_cmd);
+
+	return client->v.cmd_quit(client, cmd);
+}
+
+int client_default_cmd_quit(struct client *client,
+			    struct smtp_server_cmd_ctx *cmd)
+{
+	return submission_backend_cmd_quit(client->backend_default, cmd);
+}
+
+