Adding upstream version 1:2.3.19.1+dfsg1.upstream/1%2.3.19.1+dfsg1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1033 insertions, 0 deletions

diff --git a/src/imap-urlauth/imap-urlauth-worker.c b/src/imap-urlauth/imap-urlauth-worker.c
new file mode 100644
index 0000000..4dc413a
--- /dev/null
+++ b/src/imap-urlauth/imap-urlauth-worker.c
@@ -0,0 +1,1033 @@
+/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "array.h"
+#include "ioloop.h"
+#include "net.h"
+#include "fdpass.h"
+#include "istream.h"
+#include "ostream.h"
+#include "str.h"
+#include "str-sanitize.h"
+#include "strescape.h"
+#include "llist.h"
+#include "hostpid.h"
+#include "var-expand.h"
+#include "process-title.h"
+#include "randgen.h"
+#include "restrict-access.h"
+#include "settings-parser.h"
+#include "master-service.h"
+#include "master-interface.h"
+#include "mail-storage.h"
+#include "mail-storage-service.h"
+#include "mail-namespace.h"
+#include "imap-url.h"
+#include "imap-msgpart-url.h"
+#include "imap-urlauth.h"
+#include "imap-urlauth-fetch.h"
+#include "imap-urlauth-worker-settings.h"
+
+#include <unistd.h>
+#include <sysexits.h>
+
+#define MAX_CTRL_HANDSHAKE 255
+
+/* max. length of input lines (URLs) */
+#define MAX_INBUF_SIZE 2048
+
+/* Disconnect client after idling this many milliseconds */
+#define CLIENT_IDLE_TIMEOUT_MSECS (10*60*1000)
+
+#define IS_STANDALONE() \
+        (getenv(MASTER_IS_PARENT_ENV) == NULL)
+
+#define IMAP_URLAUTH_WORKER_PROTOCOL_MAJOR_VERSION 2
+#define IMAP_URLAUTH_WORKER_PROTOCOL_MINOR_VERSION 0
+
+struct client {
+	struct client *prev, *next;
+
+	int fd_in, fd_out, fd_ctrl;
+
+	struct io *io, *ctrl_io;
+	struct istream *input, *ctrl_input;
+	struct ostream *output, *ctrl_output;
+	struct timeout *to_idle;
+
+	char *access_user, *access_service;
+	ARRAY_TYPE(string) access_apps;
+
+	struct mail_storage_service_user *service_user;
+	struct mail_user *mail_user;
+
+	struct imap_urlauth_context *urlauth_ctx;
+
+	struct imap_msgpart_url *url;
+	struct istream *msg_part_input;
+	uoff_t msg_part_size;
+
+	/* settings: */
+	const struct imap_urlauth_worker_settings *set;
+	const struct mail_storage_settings *mail_set;
+
+	bool debug:1;
+	bool finished:1;
+	bool waiting_input:1;
+	bool version_received:1;
+	bool access_received:1;
+	bool access_anonymous:1;
+};
+
+static bool verbose_proctitle = FALSE;
+static struct mail_storage_service_ctx *storage_service;
+
+struct client *imap_urlauth_worker_clients;
+unsigned int imap_urlauth_worker_client_count;
+
+static void client_destroy(struct client *client);
+static void client_abort(struct client *client, const char *reason);
+static int client_run_url(struct client *client);
+static void client_input(struct client *client);
+static bool client_handle_input(struct client *client);
+static int client_output(struct client *client);
+
+static void client_ctrl_input(struct client *client);
+
+static void imap_urlauth_worker_refresh_proctitle(void)
+{
+	struct client *client = imap_urlauth_worker_clients;
+	string_t *title;
+
+	if (!verbose_proctitle)
+		return;
+
+	title = t_str_new(128);
+	str_append_c(title, '[');
+	switch (imap_urlauth_worker_client_count) {
+	case 0:
+		str_append(title, "idling");
+		break;
+	case 1:
+		if (client->mail_user == NULL)
+			str_append(title, client->access_user);
+		else {
+			str_append(title, client->access_user);
+			str_append(title, "->");
+			str_append(title, client->mail_user->username);
+		}
+		break;
+	default:
+		str_printfa(title, "%u connections",
+			    imap_urlauth_worker_client_count);
+		break;
+	}
+	str_append_c(title, ']');
+	process_title_set(str_c(title));
+}
+
+static void client_idle_timeout(struct client *client)
+{
+	if (client->url != NULL) {
+		client_abort(client,
+			"Session closed for inactivity in reading our output");
+	} else {
+		client_destroy(client);
+	}
+}
+
+static struct client *client_create(int fd)
+{
+	struct client *client;
+
+	/* always use nonblocking I/O */
+	net_set_nonblock(fd, TRUE);
+
+	client = i_new(struct client, 1);
+	i_array_init(&client->access_apps, 16);
+	client->fd_in = -1;
+	client->fd_out = -1;
+	client->fd_ctrl = fd;
+	client->access_anonymous = TRUE; /* default until overridden */
+
+	client->ctrl_io = io_add(fd, IO_READ, client_ctrl_input, client);
+	client->to_idle = timeout_add(CLIENT_IDLE_TIMEOUT_MSECS,
+				      client_idle_timeout, client);
+
+	imap_urlauth_worker_client_count++;
+	DLLIST_PREPEND(&imap_urlauth_worker_clients, client);
+
+	imap_urlauth_worker_refresh_proctitle();
+	return client;
+}
+
+static struct client *
+client_create_standalone(const char *access_user,
+			 const char *const *access_applications,
+			 int fd_in, int fd_out, bool debug)
+{
+	struct client *client;
+
+	/* always use nonblocking I/O */
+	net_set_nonblock(fd_in, TRUE);
+	net_set_nonblock(fd_out, TRUE);
+
+	client = i_new(struct client, 1);
+	i_array_init(&client->access_apps, 16);
+	client->fd_in = fd_in;
+	client->fd_out = fd_out;
+	client->fd_ctrl = -1;
+
+	if (access_user != NULL && *access_user != '\0')
+		client->access_user = i_strdup(access_user);
+	else {
+		client->access_user = i_strdup("anonymous");
+		client->access_anonymous = TRUE;
+	}
+	if (access_applications != NULL) {
+		const char *const *apps = access_applications;
+		for (; *apps != NULL; apps++) {
+			char *app = i_strdup(*apps);
+			array_push_back(&client->access_apps, &app);
+		}
+	}
+	client->debug = debug;
+
+	client->input = i_stream_create_fd(fd_in, MAX_INBUF_SIZE);
+	client->output = o_stream_create_fd(fd_out, SIZE_MAX);
+	client->io = io_add(fd_in, IO_READ, client_input, client);
+	client->to_idle = timeout_add(CLIENT_IDLE_TIMEOUT_MSECS,
+				      client_idle_timeout, client);
+	o_stream_set_no_error_handling(client->output, TRUE);
+	o_stream_set_flush_callback(client->output, client_output, client);
+
+	imap_urlauth_worker_client_count++;
+	DLLIST_PREPEND(&imap_urlauth_worker_clients, client);
+
+	i_set_failure_prefix("imap-urlauth[%s](%s): ",
+			     my_pid, client->access_user);
+	return client;
+}
+
+static void client_abort(struct client *client, const char *reason)
+{
+	i_error("%s", reason);
+	client_destroy(client);
+}
+
+static void client_destroy(struct client *client)
+{
+	char *app;
+
+	i_set_failure_prefix("imap-urlauth[%s](%s): ",
+			     my_pid, client->access_user);
+
+	if (client->url != NULL) {
+		/* deinitialize url */
+		i_stream_close(client->input);
+		o_stream_close(client->output);
+		(void)client_run_url(client);
+		i_assert(client->url == NULL);
+	}
+
+	imap_urlauth_worker_client_count--;
+	DLLIST_REMOVE(&imap_urlauth_worker_clients, client);
+
+	if (client->urlauth_ctx != NULL)
+		imap_urlauth_deinit(&client->urlauth_ctx);
+
+	if (client->mail_user != NULL)
+		mail_user_deinit(&client->mail_user);
+
+	io_remove(&client->io);
+	io_remove(&client->ctrl_io);
+	timeout_remove(&client->to_idle);
+
+	i_stream_destroy(&client->input);
+	o_stream_destroy(&client->output);
+
+	i_stream_destroy(&client->ctrl_input);
+	o_stream_destroy(&client->ctrl_output);
+
+	fd_close_maybe_stdio(&client->fd_in, &client->fd_out);
+	if (client->fd_ctrl >= 0)
+		net_disconnect(client->fd_ctrl);
+
+	if (client->service_user != NULL)
+		mail_storage_service_user_unref(&client->service_user);
+	i_free(client->access_user);
+	i_free(client->access_service);
+	array_foreach_elem(&client->access_apps, app)
+		i_free(app);
+	array_free(&client->access_apps);
+	i_free(client);
+
+	imap_urlauth_worker_refresh_proctitle();
+	master_service_client_connection_destroyed(master_service);
+}
+
+static int client_run_url(struct client *client)
+{
+	const unsigned char *data;
+	size_t size;
+	ssize_t ret = 0;
+
+	while (i_stream_read_more(client->msg_part_input, &data, &size) > 0) {
+		if ((ret = o_stream_send(client->output, data, size)) < 0)
+			break;
+		i_stream_skip(client->msg_part_input, ret);
+
+		if (o_stream_get_buffer_used_size(client->output) >= 4096) {
+			if ((ret = o_stream_flush(client->output)) < 0)
+				break;
+			if (ret == 0)
+				return 0;
+		}
+	}
+
+	if (client->output->closed || ret < 0) {
+		imap_msgpart_url_free(&client->url);
+		return -1;
+	}
+
+	if (client->msg_part_input->eof) {
+		o_stream_nsend(client->output, "\n", 1);
+		imap_msgpart_url_free(&client->url);
+		return 1;
+	}
+	return 0;
+}
+
+static void clients_destroy_all(void)
+{
+	while (imap_urlauth_worker_clients != NULL)
+		client_destroy(imap_urlauth_worker_clients);
+}
+
+static void ATTR_FORMAT(2, 3)
+client_send_line(struct client *client, const char *fmt, ...)
+{
+	va_list va;
+
+	if (client->output->closed)
+		return;
+
+	va_start(va, fmt);
+
+	T_BEGIN {
+		string_t *str;
+
+		str = t_str_new(256);
+		str_vprintfa(str, fmt, va);
+		str_append(str, "\n");
+
+		o_stream_nsend(client->output, str_data(str), str_len(str));
+	} T_END;
+
+	va_end(va);
+}
+
+static int
+client_fetch_urlpart(struct client *client, const char *url,
+		     enum imap_urlauth_fetch_flags url_flags,
+		     const char **bpstruct_r, bool *binary_with_nuls_r,
+		     const char **errormsg_r)
+{
+	const char *error;
+	struct imap_msgpart_open_result mpresult;
+	enum mail_error error_code;
+	int ret;
+
+	*bpstruct_r = NULL;
+	*errormsg_r = NULL;
+	*binary_with_nuls_r = FALSE;
+
+	ret = imap_urlauth_fetch(client->urlauth_ctx, url,
+				 &client->url, &error_code, &error);
+	if (ret <= 0) {
+		if (ret < 0)
+			return -1;
+		error = t_strdup_printf("Failed to fetch URLAUTH \"%s\": %s",
+					url, error);
+		if (client->debug)
+			i_debug("%s", error);
+		/* don't leak info about existence/accessibility
+		   of mailboxes */
+		if (error_code == MAIL_ERROR_PARAMS)
+			*errormsg_r = error;
+		return 0;
+	}
+
+	if ((url_flags & IMAP_URLAUTH_FETCH_FLAG_BINARY) != 0)
+		imap_msgpart_url_set_decode_to_binary(client->url);
+	if ((url_flags & IMAP_URLAUTH_FETCH_FLAG_BODYPARTSTRUCTURE) != 0) {
+		ret = imap_msgpart_url_get_bodypartstructure(client->url,
+							     bpstruct_r, &error);
+		if (ret <= 0) {
+			*errormsg_r = t_strdup_printf(
+				"Failed to read URLAUTH \"%s\": %s", url, error);
+			if (client->debug)
+				i_debug("%s", *errormsg_r);
+			return ret;
+		}
+	}
+
+	/* if requested, read the message part the URL points to */
+	if ((url_flags & IMAP_URLAUTH_FETCH_FLAG_BODY) != 0 ||
+	    (url_flags & IMAP_URLAUTH_FETCH_FLAG_BINARY) != 0) {
+		ret = imap_msgpart_url_read_part(client->url, &mpresult, &error);
+		if (ret <= 0) {
+			*errormsg_r = t_strdup_printf(
+				"Failed to read URLAUTH \"%s\": %s", url, error);
+			if (client->debug)
+				i_debug("%s", *errormsg_r);
+			return ret;
+		}
+		client->msg_part_size = mpresult.size;
+		client->msg_part_input = mpresult.input;
+		*binary_with_nuls_r = mpresult.binary_decoded_input_has_nuls;
+	}
+	return 1;
+}
+
+static int client_fetch_url(struct client *client, const char *url,
+			    enum imap_urlauth_fetch_flags url_flags)
+{
+	string_t *response;
+	const char *bpstruct, *errormsg;
+	bool binary_with_nuls;
+	int ret;
+
+	i_assert(client->url == NULL);
+
+	client->msg_part_size = 0;
+	client->msg_part_input = NULL;
+
+	if (client->debug)
+		i_debug("Fetching URLAUTH %s", url);
+
+	/* fetch URL */
+	ret = client_fetch_urlpart(client, url, url_flags, &bpstruct,
+				   &binary_with_nuls, &errormsg);
+	if (ret <= 0) {
+		/* fetch failed */
+		if (client->url != NULL)
+			imap_msgpart_url_free(&client->url);
+		/* don't send error details to anonymous users: just to be sure
+		   that no information about the target user account is unduly
+		   leaked. */
+		if (client->access_anonymous || errormsg == NULL)
+			client_send_line(client, "NO");
+		else {
+			client_send_line(client, "NO\terror=%s",
+					 str_tabescape(errormsg));
+		}
+		if (ret < 0) {
+			/* fetch failed badly */
+			client_abort(client, "Session aborted: Fatal failure while fetching URL");
+		}
+		return 0;
+	}
+
+	response = t_str_new(256);
+	str_append(response, "OK");
+	if (binary_with_nuls)
+		str_append(response, "\thasnuls");
+	if (bpstruct != NULL) {
+		str_append(response, "\tbpstruct=");
+		str_append(response, str_tabescape(bpstruct));
+		if (client->debug) {
+			i_debug("Fetched URLAUTH yielded BODYPARTSTRUCTURE (%s)",
+				bpstruct);
+		}
+	}
+
+	/* return content */
+	o_stream_cork(client->output);
+	if (client->msg_part_size == 0 || client->msg_part_input == NULL) {
+		/* empty */
+		str_append(response, "\t0");
+		client_send_line(client, "%s", str_c(response));
+
+		imap_msgpart_url_free(&client->url);
+		client->url = NULL;
+		if (client->debug)
+			i_debug("Fetched URLAUTH yielded empty result");
+	} else {
+
+		/* actual content */
+		str_printfa(response, "\t%"PRIuUOFF_T, client->msg_part_size);
+		client_send_line(client, "%s", str_c(response));
+
+		if (client->debug) {
+			i_debug("Fetched URLAUTH yielded %"PRIuUOFF_T" bytes "
+				"of %smessage data", client->msg_part_size,
+				(binary_with_nuls ? "binary " : ""));
+		}
+		if (client_run_url(client) < 0) {
+			client_abort(client,
+				"Session aborted: Fatal failure while transferring URL");
+			return 0;
+		}		
+	}
+
+	if (client->url != NULL) {
+		/* URL not finished */
+		o_stream_set_flush_pending(client->output, TRUE);
+		client->waiting_input = TRUE;
+	}
+	o_stream_uncork(client->output);
+	return client->url != NULL ? 0 : 1;
+}
+
+static int
+client_handle_command(struct client *client, const char *cmd,
+		      const char *const *args, const char **error_r)
+{
+	int ret;
+
+	*error_r = NULL;
+
+	/* "URL"["\tbody"]["\tbinary"]["\tbpstruct"]"\t"<url>:
+	   fetch URL (meta)data */
+	if (strcmp(cmd, "URL") == 0) {
+		enum imap_urlauth_fetch_flags url_flags = 0;
+		const char *url;
+
+		if (*args == NULL) {
+			*error_r = "URL: Missing URL parameter";
+			return -1;
+		}
+
+		url = *args;
+	
+		args++;
+		while (*args != NULL) {
+			if (strcasecmp(*args, "body") == 0)
+				url_flags |= IMAP_URLAUTH_FETCH_FLAG_BODY;
+			else if (strcasecmp(*args, "binary") == 0)
+				url_flags |= IMAP_URLAUTH_FETCH_FLAG_BINARY;
+			else if (strcasecmp(*args, "bpstruct") == 0)
+				url_flags |= IMAP_URLAUTH_FETCH_FLAG_BODYPARTSTRUCTURE;
+
+			args++;
+		}
+
+		if (url_flags == 0)
+			url_flags = IMAP_URLAUTH_FETCH_FLAG_BODY;
+
+		T_BEGIN {
+			ret = client_fetch_url(client, url, url_flags);
+		} T_END;
+		return ret;
+	}
+
+	/* "END": unselect current user (closes worker) */
+	if (strcmp(cmd, "END") == 0) {
+		if (args[0] != NULL) {
+			*error_r = "END: Invalid number of parameters";
+			return -1;
+		}
+
+		client->finished = TRUE;
+		if (client->ctrl_output != NULL)
+			o_stream_nsend_str(client->ctrl_output, "FINISHED\n");
+		client_destroy(client);
+		return 0;
+	}
+
+	*error_r = t_strconcat("Unknown or inappropriate command: ", cmd, NULL);
+	return -1;
+}
+
+static int
+client_handle_user_command(struct client *client, const char *cmd,
+			   const char *const *args, const char **error_r)
+{
+	struct mail_storage_service_input input;
+	struct imap_urlauth_worker_settings *set;
+	struct mail_storage_service_user *user;
+	struct imap_urlauth_config config;
+	struct mail_user *mail_user;
+	const char *error;
+	unsigned int count;
+	int ret;
+
+	/* "USER\t"<username> */
+	*error_r = NULL;
+
+	/* check command syntax */
+	if (strcmp(cmd, "USER") != 0) {
+		*error_r = t_strconcat("Unknown or inappropriate command: ",
+				       cmd, NULL);
+		return -1;
+	}
+
+	if (args[0] == NULL || args[1] != NULL) {
+		*error_r = "USER: Invalid number of parameters";
+		return -1;
+	}
+
+	/* lookup user */
+	i_zero(&input);
+	input.module = "imap-urlauth-worker";
+	input.service = "imap-urlauth-worker";
+	input.username = args[0];
+
+	if (client->debug)
+		i_debug("Looking up user %s", input.username);
+
+	ret = mail_storage_service_lookup_next(storage_service, &input,
+					       &user, &mail_user, &error);
+	if (ret < 0) {
+		i_error("Failed to lookup user %s: %s", input.username, error);
+		client_abort(client, "Session aborted: Failed to lookup user");
+		return 0;
+	} else if (ret == 0) {
+		if (client->debug)
+			i_debug("User %s doesn't exist", input.username);
+
+		client_send_line(client, "NO");
+		return 1;
+	}
+
+	client->debug = mail_user->mail_debug =
+		client->debug || mail_user->mail_debug;
+
+	/* drop privileges */
+	restrict_access_allow_coredumps(TRUE);
+
+	set = mail_storage_service_user_get_set(user)[1];
+	if (settings_var_expand(&imap_urlauth_worker_setting_parser_info, set,
+				mail_user->pool,
+				mail_user_var_expand_table(mail_user),
+				&error) <= 0) {
+		client_send_line(client, "NO");
+		client_abort(client, t_strdup_printf(
+			"Session aborted: Failed to expand settings: %s", error));
+		return 0;
+	}
+
+	if (set->verbose_proctitle) {
+		verbose_proctitle = TRUE;
+		imap_urlauth_worker_refresh_proctitle();
+	}
+
+	client->service_user = user;
+	client->mail_user = mail_user;
+	client->set = set;
+
+	if (client->debug) {
+		i_debug("Found user account `%s' on behalf of user `%s'",
+			mail_user->username, client->access_user);
+	}
+
+	/* initialize urlauth context */
+	if (*set->imap_urlauth_host == '\0') {
+		i_error("imap_urlauth_host setting is not configured for user %s",
+			mail_user->username);
+		client_send_line(client, "NO");
+		client_abort(client, "Session aborted: URLAUTH not configured");
+		return 0;
+	}
+
+	i_zero(&config);
+	config.url_host = set->imap_urlauth_host;
+	config.url_port = set->imap_urlauth_port;
+	config.access_user = client->access_user;
+	config.access_service = client->access_service;
+	config.access_anonymous = client->access_anonymous;
+	config.access_applications =
+		(const void *)array_get(&client->access_apps, &count);
+		
+	client->urlauth_ctx = imap_urlauth_init(client->mail_user, &config);
+	if (client->debug) {
+		i_debug("Providing access to user account `%s' on behalf of user `%s' "
+			"using service `%s'", mail_user->username, client->access_user,
+			client->access_service);
+	}
+
+	i_set_failure_prefix("imap-urlauth[%s](%s->%s): ",
+			     my_pid, client->access_user, mail_user->username);
+
+	client_send_line(client, "OK");
+	return 1;
+}
+
+static bool client_handle_input(struct client *client)
+{
+	const char *line, *cmd, *error;
+	int ret;
+
+	if (client->url != NULL) {
+		/* we're still processing a URL. wait until it's
+		   finished. */
+		io_remove(&client->io);
+		client->io = NULL;
+		client->waiting_input = TRUE;
+		return TRUE;
+	}
+
+	if (client->io == NULL) {
+		client->io = io_add(client->fd_in, IO_READ,
+				    client_input, client);
+	}
+	client->waiting_input = FALSE;
+	timeout_reset(client->to_idle);
+
+	switch (i_stream_read(client->input)) {
+	case -1:
+		/* disconnected */
+		if (client->ctrl_output != NULL)
+			o_stream_nsend_str(client->ctrl_output, "DISCONNECTED\n");
+		client_destroy(client);
+		return FALSE;
+	case -2:
+		/* line too long, kill it */
+		client_abort(client, "Session aborted: Input line too long");
+		return FALSE;
+	}
+
+	while ((line = i_stream_next_line(client->input)) != NULL) {
+		const char *const *args = t_strsplit_tabescaped(line);
+
+		if (args[0] == NULL)
+			continue;
+		cmd = args[0]; args++;
+
+		if (client->mail_user == NULL)
+			ret = client_handle_user_command(client, cmd, args, &error);
+		else
+			ret = client_handle_command(client, cmd, args, &error);
+
+		if (ret <= 0) {
+			if (ret == 0)
+				break;
+			i_error("Client input error: %s", error);
+			client_abort(client, "Session aborted: Unexpected input");
+			return FALSE;
+		}
+	}
+	return TRUE;
+}
+
+static void client_input(struct client *client)
+{
+	(void)client_handle_input(client);
+}
+
+static int client_output(struct client *client)
+{
+	if (o_stream_flush(client->output) < 0) {
+		if (client->ctrl_output != NULL)
+			o_stream_nsend_str(client->ctrl_output, "DISCONNECTED\n");
+		client_destroy(client);
+		return 1;
+	}
+	timeout_reset(client->to_idle);
+
+	if (client->url != NULL) {
+		if (client_run_url(client) < 0) {
+			client_destroy(client);
+			return 1;
+		}
+
+		if (client->url == NULL && client->waiting_input) {
+			if (!client_handle_input(client)) {
+				/* client got destroyed */
+				return 1;
+			}
+		}
+	}
+
+	if (client->url != NULL) {
+		/* url not finished yet */
+		return 0;
+	} else if (client->io == NULL) {
+		/* data still in output buffer, get back here to add IO */
+		return 0;
+	} else {
+		return 1;
+	}
+}
+
+static int
+client_ctrl_read_fds(struct client *client)
+{
+	unsigned char data = 0;
+	ssize_t ret = 1;
+
+	if (client->fd_in == -1) {
+		ret = fd_read(client->fd_ctrl, &data,
+			      sizeof(data), &client->fd_in);
+		if (ret > 0 && data == '0')
+			client->fd_out = client->fd_in;
+	}
+	if (ret > 0 && client->fd_out == -1) {
+		ret = fd_read(client->fd_ctrl, &data,
+			      sizeof(data), &client->fd_out);
+	}
+
+	if (ret == 0) {
+		/* unexpectedly disconnected */
+		client_destroy(client);
+		return 0;
+	} else if (ret < 0) {
+		if (errno == EAGAIN)
+			return 0;
+		i_error("fd_read() failed: %m");
+		return -1;
+	} else if (data != '0') {
+		i_error("fd_read() returned invalid byte 0x%2x", data);
+		return -1;
+	}
+
+	if (client->fd_in == -1 || client->fd_out == -1) {
+		i_error("Handshake is missing a file descriptor");
+		return -1;
+	}
+
+	client->ctrl_input =
+		i_stream_create_fd(client->fd_ctrl, MAX_INBUF_SIZE);
+	client->ctrl_output = o_stream_create_fd(client->fd_ctrl, SIZE_MAX);
+	o_stream_set_no_error_handling(client->ctrl_output, TRUE);
+	return 1;
+}
+
+static void client_ctrl_input(struct client *client)
+{
+	const char *const *args;
+	const char *line;
+	int ret;
+
+	timeout_reset(client->to_idle);
+
+	if (client->fd_in == -1 || client->fd_out == -1) {
+		if ((ret = client_ctrl_read_fds(client)) <= 0) {
+			if (ret < 0)
+				client_abort(client, "FD Transfer failed");
+			return;
+		}
+	}
+
+	switch (i_stream_read(client->ctrl_input)) {
+	case -1:
+		/* disconnected */
+		client_destroy(client);
+		return;
+	case -2:
+		/* line too long, kill it */
+		client_abort(client,
+			     "Control session aborted: Input line too long");
+		return;
+	}
+
+	if (!client->version_received) {
+		if ((line = i_stream_next_line(client->ctrl_input)) == NULL)
+			return;
+
+		if (!version_string_verify(line, "imap-urlauth-worker",
+				IMAP_URLAUTH_WORKER_PROTOCOL_MAJOR_VERSION)) {
+			i_error("imap-urlauth-worker client not compatible with this server "
+				"(mixed old and new binaries?) %s", line);
+			client_abort(client, "Control session aborted: Version mismatch");
+			return;
+		}
+
+		client->version_received = TRUE;
+		if (o_stream_send_str(client->ctrl_output, "OK\n") < 0) {
+			client_destroy(client);
+			return;
+		}
+	}
+
+	if (client->access_received) {
+		client_abort(client, "Control session aborted: Unexpected input");
+		return;
+	}
+
+	if ((line = i_stream_next_line(client->ctrl_input)) == NULL)
+		return;
+
+	args = t_strsplit_tabescaped(line);
+	if (*args == NULL || strcmp(*args, "ACCESS") != 0) {
+		i_error("Invalid control command: %s", str_sanitize(line, 80));
+		client_abort(client, "Control session aborted: Invalid command");
+		return;
+	}
+	args++;
+	if (args[0] == NULL || args[1] == NULL) {
+		i_error("Invalid ACCESS command: %s", str_sanitize(line, 80));
+		client_abort(client, "Control session aborted: Invalid command");
+		return;
+	}
+
+	i_assert(client->access_user == NULL);
+	i_assert(client->access_service == NULL);
+	if (**args != '\0') {
+		client->access_user = i_strdup(*args);
+		client->access_anonymous = FALSE;
+	} else {
+		client->access_user = i_strdup("anonymous");
+		client->access_anonymous = TRUE;
+	}
+	args++;
+	client->access_service = i_strdup(*args);
+
+	i_set_failure_prefix("imap-urlauth[%s](%s): ",
+			     my_pid, client->access_user);
+
+	args++;
+	while (*args != NULL) {
+		/* debug */
+		if (strcasecmp(*args, "debug") == 0) {
+			client->debug = TRUE;
+		/* apps=<access-application>[,<access-application,...] */
+		} else if (strncasecmp(*args, "apps=", 5) == 0 &&
+			   (*args)[5] != '\0') {
+			const char *const *apps = t_strsplit(*args+5, ",");
+
+			while (*apps != NULL) {
+				char *app = i_strdup(*apps);
+
+				array_push_back(&client->access_apps, &app);
+				if (client->debug) {
+					i_debug("User %s has URLAUTH %s access",
+						client->access_user, app);
+				}
+				apps++;
+			}
+		} else {
+			i_error("Invalid ACCESS parameter: %s", str_sanitize(*args, 80));
+			client_abort(client, "Control session aborted: Invalid command");
+			return;
+		} 
+		args++;
+	}
+
+	client->access_received = TRUE;
+
+	if (o_stream_send_str(client->ctrl_output, "OK\n") < 0) {
+		client_destroy(client);
+		return;
+	}
+
+	client->input = i_stream_create_fd(client->fd_in, MAX_INBUF_SIZE);
+	client->output = o_stream_create_fd(client->fd_out, SIZE_MAX);
+	client->io = io_add(client->fd_in, IO_READ, client_input, client);
+	o_stream_set_no_error_handling(client->output, TRUE);
+	o_stream_set_flush_callback(client->output, client_output, client);
+
+	if (client->debug) {
+		i_debug("Worker activated for access by user `%s' using service `%s'",
+			client->access_user, client->access_service);
+	}
+}
+
+static void imap_urlauth_worker_die(void)
+{
+	/* do nothing */
+}
+
+static void main_stdio_run(const char *access_user,
+			   const char *const *access_applications)
+{
+	bool debug;
+
+	debug = getenv("DEBUG") != NULL;
+	access_user = access_user != NULL ? access_user : getenv("USER");
+	if (access_user == NULL && IS_STANDALONE())
+		access_user = getlogin();
+	if (access_user == NULL)
+		i_fatal("USER environment missing");
+
+	(void)client_create_standalone(access_user, access_applications,
+				       STDIN_FILENO, STDOUT_FILENO, debug);
+}
+
+static void client_connected(struct master_service_connection *conn)
+{
+	master_service_client_connection_accept(conn);
+	(void)client_create(conn->fd);
+}
+
+int main(int argc, char *argv[])
+{
+	static const struct setting_parser_info *set_roots[] = {
+		&imap_urlauth_worker_setting_parser_info,
+		NULL
+	};
+	enum master_service_flags service_flags = 0;
+	enum mail_storage_service_flags storage_service_flags =
+		MAIL_STORAGE_SERVICE_FLAG_USERDB_LOOKUP |
+		MAIL_STORAGE_SERVICE_FLAG_NO_LOG_INIT;
+	ARRAY_TYPE (const_string) access_apps;
+	const char *access_user = NULL;
+	int c;
+
+	if (IS_STANDALONE()) {
+		service_flags |= MASTER_SERVICE_FLAG_STANDALONE |
+			MASTER_SERVICE_FLAG_STD_CLIENT;
+	} else {
+		service_flags |= MASTER_SERVICE_FLAG_KEEP_CONFIG_OPEN;
+	}
+
+	master_service = master_service_init("imap-urlauth-worker", service_flags,
+					     &argc, &argv, "a:");
+
+	t_array_init(&access_apps, 4);
+	while ((c = master_getopt(master_service)) > 0) {
+		switch (c) {
+		case 'a': {
+			const char *app = t_strdup(optarg);
+
+			array_push_back(&access_apps, &app);
+			break;
+		}
+		default:
+			return FATAL_DEFAULT;
+		}
+	}
+
+	if ( optind < argc ) {
+		access_user = argv[optind++];
+	}
+
+	if (optind != argc) {
+		i_fatal_status(EX_USAGE, "Unknown argument: %s", argv[optind]);
+	}
+
+	master_service_init_log_with_pid(master_service);
+	master_service_set_die_callback(master_service, imap_urlauth_worker_die);
+
+	storage_service =
+		mail_storage_service_init(master_service,
+					  set_roots, storage_service_flags);
+	master_service_init_finish(master_service);
+
+	/* fake that we're running, so we know if client was destroyed
+	   while handling its initial input */
+	io_loop_set_running(current_ioloop);
+
+	if (IS_STANDALONE()) {
+		T_BEGIN {
+			if (array_count(&access_apps) > 0) {
+				(void)array_append_space(&access_apps);
+				main_stdio_run(access_user,
+					       array_front(&access_apps));
+			} else {
+				main_stdio_run(access_user, NULL);
+			}
+		} T_END;
+	} else {
+		io_loop_set_running(current_ioloop);
+	}
+
+	if (io_loop_is_running(current_ioloop))
+		master_service_run(master_service, client_connected);
+	clients_destroy_all();
+
+	mail_storage_service_deinit(&storage_service);
+	master_service_deinit(&master_service);
+	return 0;
+}