master-settings.c   [plain text]

/* Copyright (c) 2005-2011 Dovecot authors, see the included COPYING file */

#include "common.h"
#include "array.h"
#include "env-util.h"
#include "istream.h"
#include "network.h"
#include "str.h"
#include "ipwd.h"
#include "mkdir-parents.h"
#include "safe-mkdir.h"
#include "settings-parser.h"
#include "master-settings.h"

#include <stddef.h>
#include <dirent.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/wait.h>

static bool master_settings_verify(void *_set, pool_t pool,
				   const char **error_r);

extern const struct setting_parser_info service_setting_parser_info;

#undef DEF
#define DEF(type, name) \
	{ type, #name, offsetof(struct file_listener_settings, name), NULL }

static const struct setting_define file_listener_setting_defines[] = {
	DEF(SET_STR, path),
	DEF(SET_UINT_OCT, mode),
	DEF(SET_STR, user),
	DEF(SET_STR, group),

	SETTING_DEFINE_LIST_END
};

static const struct file_listener_settings file_listener_default_settings = {
	.path = "",
	.mode = 0600,
	.user = "",
	.group = "",
};

static const struct setting_parser_info file_listener_setting_parser_info = {
	.defines = file_listener_setting_defines,
	.defaults = &file_listener_default_settings,

	.type_offset = offsetof(struct file_listener_settings, path),
	.struct_size = sizeof(struct file_listener_settings),

	.parent_offset = (size_t)-1,
	.parent = &service_setting_parser_info
};

#undef DEF
#define DEF(type, name) \
	{ type, #name, offsetof(struct inet_listener_settings, name), NULL }

static const struct setting_define inet_listener_setting_defines[] = {
	DEF(SET_STR, name),
	DEF(SET_STR, address),
	DEF(SET_UINT, port),
	DEF(SET_BOOL, ssl),

	SETTING_DEFINE_LIST_END
};

static const struct inet_listener_settings inet_listener_default_settings = {
	.name = "",
	.address = "",
	.port = 0,
	.ssl = FALSE
};

static const struct setting_parser_info inet_listener_setting_parser_info = {
	.defines = inet_listener_setting_defines,
	.defaults = &inet_listener_default_settings,

	.type_offset = offsetof(struct inet_listener_settings, name),
	.struct_size = sizeof(struct inet_listener_settings),

	.parent_offset = (size_t)-1,
	.parent = &service_setting_parser_info
};

#undef DEF
#undef DEFLIST
#undef DEFLIST_UNIQUE
#define DEF(type, name) \
	{ type, #name, offsetof(struct service_settings, name), NULL }
#define DEFLIST(field, name, defines) \
	{ SET_DEFLIST, name, offsetof(struct service_settings, field), defines }
#define DEFLIST_UNIQUE(field, name, defines) \
	{ SET_DEFLIST_UNIQUE, name, offsetof(struct service_settings, field), defines }

static const struct setting_define service_setting_defines[] = {
	DEF(SET_STR, name),
	DEF(SET_STR, protocol),
	DEF(SET_STR, type),
	DEF(SET_STR, executable),
	DEF(SET_STR, user),
	DEF(SET_STR, group),
	DEF(SET_STR, privileged_group),
	DEF(SET_STR, extra_groups),
	DEF(SET_STR, chroot),

	DEF(SET_BOOL, drop_priv_before_exec),

	DEF(SET_UINT, process_min_avail),
	DEF(SET_UINT, process_limit),
	DEF(SET_UINT, client_limit),
	DEF(SET_UINT, service_count),
	DEF(SET_TIME, idle_kill),
	DEF(SET_SIZE, vsz_limit),

	DEFLIST_UNIQUE(unix_listeners, "unix_listener",
		       &file_listener_setting_parser_info),
	DEFLIST_UNIQUE(fifo_listeners, "fifo_listener",
		       &file_listener_setting_parser_info),
	DEFLIST_UNIQUE(inet_listeners, "inet_listener",
		       &inet_listener_setting_parser_info),

	SETTING_DEFINE_LIST_END
};

static const struct service_settings service_default_settings = {
	.name = "",
	.protocol = "",
	.type = "",
	.executable = "",
	.user = "",
	.group = "",
	.privileged_group = "",
	.extra_groups = "",
	.chroot = "",

	.drop_priv_before_exec = FALSE,

	.process_min_avail = 0,
	.process_limit = 0,
	.client_limit = 0,
	.service_count = 0,
	.idle_kill = 0,
	.vsz_limit = (uoff_t)-1,

	.unix_listeners = ARRAY_INIT,
	.fifo_listeners = ARRAY_INIT,
	.inet_listeners = ARRAY_INIT
};

const struct setting_parser_info service_setting_parser_info = {
	.defines = service_setting_defines,
	.defaults = &service_default_settings,

	.type_offset = offsetof(struct service_settings, name),
	.struct_size = sizeof(struct service_settings),

	.parent_offset = offsetof(struct service_settings, master_set),
	.parent = &master_setting_parser_info
};

#undef DEF
#undef DEFLIST_UNIQUE
#define DEF(type, name) \
	{ type, #name, offsetof(struct master_settings, name), NULL }
#define DEFLIST_UNIQUE(field, name, defines) \
	{ SET_DEFLIST_UNIQUE, name, offsetof(struct master_settings, field), defines }

static const struct setting_define master_setting_defines[] = {
	DEF(SET_STR, base_dir),
	DEF(SET_STR, libexec_dir),
	DEF(SET_STR, import_environment),
	DEF(SET_STR, protocols),
	DEF(SET_STR, listen),
	DEF(SET_ENUM, ssl),
	DEF(SET_STR, default_internal_user),
	DEF(SET_STR, default_login_user),
	DEF(SET_UINT, default_process_limit),
	DEF(SET_UINT, default_client_limit),
	DEF(SET_UINT, default_idle_kill),
	DEF(SET_SIZE, default_vsz_limit),

	DEF(SET_BOOL, version_ignore),

	DEF(SET_UINT, first_valid_uid),
	DEF(SET_UINT, last_valid_uid),
	DEF(SET_UINT, first_valid_gid),
	DEF(SET_UINT, last_valid_gid),

	DEFLIST_UNIQUE(services, "service", &service_setting_parser_info),

	SETTING_DEFINE_LIST_END
};

/* <settings checks> */
#ifdef HAVE_SYSTEMD
#  define ENV_SYSTEMD " LISTEN_PID LISTEN_FDS"
#else
#  define ENV_SYSTEMD ""
#endif
#ifdef DEBUG
#  define ENV_GDB " GDB"
#else
#  define ENV_GDB ""
#endif
/* </settings checks> */

static const struct master_settings master_default_settings = {
	.base_dir = PKG_RUNDIR,
	.libexec_dir = PKG_LIBEXECDIR,
	.import_environment = "TZ" ENV_SYSTEMD ENV_GDB,
	.protocols = "imap pop3 lmtp",
	.listen = "*, ::",
	.ssl = "yes:no:required",
	.default_internal_user = "dovecot",
	.default_login_user = "dovenull",
	.default_process_limit = 100,
	.default_client_limit = 1000,
	.default_idle_kill = 60,
	.default_vsz_limit = 256*1024*1024,

	.version_ignore = FALSE,

	.first_valid_uid = 500,
	.last_valid_uid = 0,
	.first_valid_gid = 1,
	.last_valid_gid = 0,

#ifndef CONFIG_BINARY
	.services = ARRAY_INIT
#else
	.services = { { &config_all_services_buf,
			     sizeof(struct service_settings *) } },
#endif
};

const struct setting_parser_info master_setting_parser_info = {
	.module_name = "master",
	.defines = master_setting_defines,
	.defaults = &master_default_settings,

	.type_offset = (size_t)-1,
	.struct_size = sizeof(struct master_settings),

	.parent_offset = (size_t)-1,

	.check_func = master_settings_verify
};

/* <settings checks> */
static void
expand_user(const char **user, enum service_user_default *default_r,
	    const struct master_settings *set)
{
	/* $variable expansion is typically done by doveconf, but these
	   variables can come from built-in settings, so we need to expand
	   them here */
	if (strcmp(*user, "$default_internal_user") == 0) {
		*user = set->default_internal_user;
		*default_r = SERVICE_USER_DEFAULT_INTERNAL;
	} else if (strcmp(*user, "$default_login_user") == 0) {
		*user = set->default_login_user;
		*default_r = SERVICE_USER_DEFAULT_LOGIN;
	} else {
		*default_r = SERVICE_USER_DEFAULT_NONE;
	}
}

static void
fix_file_listener_paths(ARRAY_TYPE(file_listener_settings) *l,
			pool_t pool, const struct master_settings *master_set,
			ARRAY_TYPE(const_string) *all_listeners)
{
	struct file_listener_settings *const *sets;
	unsigned int base_dir_len = strlen(master_set->base_dir);
	enum service_user_default user_default;

	if (!array_is_created(l))
		return;

	array_foreach(l, sets) {
		struct file_listener_settings *set = *sets;

		expand_user(&set->user, &user_default, master_set);
		if (*set->path != '/') {
			set->path = p_strconcat(pool, master_set->base_dir, "/",
						set->path, NULL);
		} else if (strncmp(set->path, master_set->base_dir,
				   base_dir_len) == 0 &&
			   set->path[base_dir_len] == '/') {
			i_warning("You should remove base_dir prefix from "
				  "unix_listener: %s", set->path);
		}
		if (set->mode != 0)
			array_append(all_listeners, &set->path, 1);
	}
}

static void add_inet_listeners(ARRAY_TYPE(inet_listener_settings) *l,
			       ARRAY_TYPE(const_string) *all_listeners)
{
	struct inet_listener_settings *const *sets;
	const char *str;

	if (!array_is_created(l))
		return;

	array_foreach(l, sets) {
		struct inet_listener_settings *set = *sets;

		if (set->port != 0) {
			str = t_strdup_printf("%d:%s", set->port, set->address);
			array_append(all_listeners, &str, 1);
		}
	}
}

static bool master_settings_parse_type(struct service_settings *set,
				       const char **error_r)
{
	if (*set->type == '\0')
		set->parsed_type = SERVICE_TYPE_UNKNOWN;
	else if (strcmp(set->type, "log") == 0)
		set->parsed_type = SERVICE_TYPE_LOG;
	else if (strcmp(set->type, "config") == 0)
		set->parsed_type = SERVICE_TYPE_CONFIG;
	else if (strcmp(set->type, "anvil") == 0)
		set->parsed_type = SERVICE_TYPE_ANVIL;
	else if (strcmp(set->type, "login") == 0)
		set->parsed_type = SERVICE_TYPE_LOGIN;
	else if (strcmp(set->type, "startup") == 0)
		set->parsed_type = SERVICE_TYPE_STARTUP;
	else {
		*error_r = t_strconcat("Unknown service type: ",
				       set->type, NULL);
		return FALSE;
	}
	return TRUE;
}

static void service_set_login_dump_core(struct service_settings *set)
{
	const char *p;

	if (set->parsed_type != SERVICE_TYPE_LOGIN)
		return;

	p = strstr(set->executable, " -D");
	if (p != NULL && (p[3] == '\0' || p[3] == ' '))
		set->login_dump_core = TRUE;
}

static bool
services_have_protocol(struct master_settings *set, const char *name)
{
	struct service_settings *const *services;

	array_foreach(&set->services, services) {
		struct service_settings *service = *services;

		if (strcmp(service->protocol, name) == 0)
			return TRUE;
	}
	return FALSE;
}

#ifdef CONFIG_BINARY
static const struct service_settings *
master_default_settings_get_service(const char *name)
{
	extern struct master_settings master_default_settings;
	struct service_settings *const *setp;

	array_foreach(&master_default_settings.services, setp) {
		if (strcmp((*setp)->name, name) == 0)
			return *setp;
	}
	return NULL;
}
#endif

static unsigned int
service_get_client_limit(struct master_settings *set, const char *name)
{
	struct service_settings *const *servicep;

	array_foreach(&set->services, servicep) {
		if (strcmp((*servicep)->name, name) == 0) {
			if ((*servicep)->client_limit != 0)
				return (*servicep)->client_limit;
			else
				return set->default_client_limit;
		}
	}
	return set->default_client_limit;
}

static bool
master_settings_verify(void *_set, pool_t pool, const char **error_r)
{
	static int warned_auth = FALSE, warned_anvil = FALSE;
#ifdef CONFIG_BINARY
	const struct service_settings *default_service;
#endif
	struct master_settings *set = _set;
	struct service_settings *const *services;
	const char *const *strings;
	ARRAY_TYPE(const_string) all_listeners;
	struct passwd pw;
	unsigned int i, j, count, len, client_limit, process_limit;
	unsigned int max_auth_client_processes, max_anvil_client_processes;

	len = strlen(set->base_dir);
	if (len > 0 && set->base_dir[len-1] == '/') {
		/* drop trailing '/' */
		set->base_dir = p_strndup(pool, set->base_dir, len - 1);
	}

	if (set->last_valid_uid != 0 &&
	    set->first_valid_uid > set->last_valid_uid) {
		*error_r = "first_valid_uid can't be larger than last_valid_uid";
		return FALSE;
	}
	if (set->last_valid_gid != 0 &&
	    set->first_valid_gid > set->last_valid_gid) {
		*error_r = "first_valid_gid can't be larger than last_valid_gid";
		return FALSE;
	}

	if (i_getpwnam(set->default_login_user, &pw) == 0) {
		*error_r = t_strdup_printf("default_login_user doesn't exist: %s",
					   set->default_login_user);
		return FALSE;
	}
	if (i_getpwnam(set->default_internal_user, &pw) == 0) {
		*error_r = t_strdup_printf("default_internal_user doesn't exist: %s",
					   set->default_internal_user);
		return FALSE;
	}

	/* check that we have at least one service. the actual service
	   structure validity is checked later while creating them. */
	if (!array_is_created(&set->services) ||
	    array_count(&set->services) == 0) {
		*error_r = "No services defined";
		return FALSE;
	}
	services = array_get(&set->services, &count);
	for (i = 0; i < count; i++) {
		struct service_settings *service = services[i];

		if (*service->name == '\0') {
			*error_r = t_strdup_printf(
				"Service #%d is missing name", i);
			return FALSE;
		}
		if (!master_settings_parse_type(service, error_r))
			return FALSE;
		for (j = 0; j < i; j++) {
			if (strcmp(service->name, services[j]->name) == 0) {
				*error_r = t_strdup_printf(
					"Duplicate service name: %s",
					service->name);
				return FALSE;
			}
		}
		expand_user(&service->user, &service->user_default, set);
		service_set_login_dump_core(service);
	}
	set->protocols_split = p_strsplit_spaces(pool, set->protocols, " ");
	if (set->protocols_split[0] != NULL &&
	    strcmp(set->protocols_split[0], "none") == 0 &&
	    set->protocols_split[1] == NULL)
		set->protocols_split[0] = NULL;

	for (i = 0; set->protocols_split[i] != NULL; i++) {
		if (!services_have_protocol(set, set->protocols_split[i])) {
			*error_r = t_strdup_printf("protocols: "
						   "Unknown protocol: %s",
						   set->protocols_split[i]);
			return FALSE;
		}
	}
	t_array_init(&all_listeners, 64);
	max_auth_client_processes = 0;
	max_anvil_client_processes = 2; /* blocking, nonblocking pipes */
	for (i = 0; i < count; i++) {
		struct service_settings *service = services[i];

		if (*service->executable == '\0') {
			*error_r = t_strdup_printf("service(%s): "
				"executable is empty", service->name);
			return FALSE;
		}
		if (*service->executable != '/') {
			service->executable =
				p_strconcat(pool, set->libexec_dir, "/",
					    service->executable, NULL);
		}
		if (*service->chroot != '/' && *service->chroot != '\0') {
			service->chroot =
				p_strconcat(pool, set->base_dir, "/",
					    service->chroot, NULL);
		}
		if (service->drop_priv_before_exec &&
		    *service->chroot != '\0') {
			*error_r = t_strdup_printf("service(%s): "
				"drop_priv_before_exec=yes can't be "
				"used with chroot", service->name);
			return FALSE;
		}
		process_limit = service->process_limit;
		if (process_limit == 0)
			process_limit = set->default_process_limit;
		if (service->process_min_avail > process_limit) {
			*error_r = t_strdup_printf("service(%s): "
				"process_min_avail is higher than process_limit",
				service->name);
			return FALSE;
		}
		if (service->vsz_limit < 1024*1024 && service->vsz_limit != 0) {
			*error_r = t_strdup_printf("service(%s): "
				"vsz_limit is too low", service->name);
			return FALSE;
		}

#ifdef CONFIG_BINARY
		default_service =
			master_default_settings_get_service(service->name);
		if (default_service != NULL &&
		    default_service->process_limit_1 && process_limit > 1) {
			*error_r = t_strdup_printf("service(%s): "
				"process_limit must be 1", service->name);
			return FALSE;
		}
#endif

		if (*service->protocol != '\0' &&
		    str_array_find((const char **)set->protocols_split,
				   service->protocol)) {
			/* each imap/pop3/lmtp process can use up a connection,
			   although if service_count=1 it's only temporary */
			max_auth_client_processes += process_limit;
		}
		if (strcmp(service->type, "login") == 0 ||
		    strcmp(service->name, "auth") == 0)
			max_anvil_client_processes += process_limit;

		fix_file_listener_paths(&service->unix_listeners,
					pool, set, &all_listeners);
		fix_file_listener_paths(&service->fifo_listeners,
					pool, set, &all_listeners);
		add_inet_listeners(&service->inet_listeners, &all_listeners);
	}

	client_limit = service_get_client_limit(set, "auth");
	if (client_limit < max_auth_client_processes && !warned_auth) {
		warned_auth = TRUE;
		i_warning("service auth { client_limit=%u } is lower than "
			  "required under max. load (%u)",
			  client_limit, max_auth_client_processes);
	}

	client_limit = service_get_client_limit(set, "anvil");
	if (client_limit < max_anvil_client_processes && !warned_anvil) {
		warned_anvil = TRUE;
		i_warning("service anvil { client_limit=%u } is lower than "
			  "required under max. load (%u)",
			  client_limit, max_anvil_client_processes);
	}

	/* check for duplicate listeners */
	array_sort(&all_listeners, i_strcmp_p);
	strings = array_get(&all_listeners, &count);
	for (i = 1; i < count; i++) {
		if (strcmp(strings[i-1], strings[i]) == 0) {
			*error_r = t_strdup_printf("duplicate listener: %s",
						   strings[i]);
			return FALSE;
		}
	}
	return TRUE;
}
/* </settings checks> */

static bool
login_want_core_dumps(const struct master_settings *set, gid_t *gid_r)
{
	struct service_settings *const *services;
	const char *error;
	bool cores = FALSE;
	uid_t uid;

	*gid_r = (gid_t)-1;

	array_foreach(&set->services, services) {
		struct service_settings *service = *services;

		if (service->parsed_type == SERVICE_TYPE_LOGIN) {
			if (service->login_dump_core)
				cores = TRUE;
			(void)get_uidgid(service->user, &uid, gid_r, &error);
			if (*service->group != '\0')
				(void)get_gid(service->group, gid_r, &error);
		}
	}
	return cores;
}

static bool
settings_have_auth_unix_listeners_in(const struct master_settings *set,
				     const char *dir)
{
	struct service_settings *const *services;
	struct file_listener_settings *const *uls;

	array_foreach(&set->services, services) {
		struct service_settings *service = *services;

		if (array_is_created(&service->unix_listeners)) {
			array_foreach(&service->unix_listeners, uls) {
				struct file_listener_settings *u = *uls;

				if (strncmp(u->path, dir, strlen(dir)) == 0)
					return TRUE;
			}
		}
	}
	return FALSE;
}

static void unlink_sockets(const char *path, const char *prefix)
{
	DIR *dirp;
	struct dirent *dp;
	struct stat st;
	string_t *str;
	unsigned int prefix_len;

	dirp = opendir(path);
	if (dirp == NULL) {
		i_error("opendir(%s) failed: %m", path);
		return;
	}

	prefix_len = strlen(prefix);
	str = t_str_new(256);
	while ((dp = readdir(dirp)) != NULL) {
		if (dp->d_name[0] == '.')
			continue;

		if (strncmp(dp->d_name, prefix, prefix_len) != 0)
			continue;

		str_truncate(str, 0);
		str_printfa(str, "%s/%s", path, dp->d_name);
		if (lstat(str_c(str), &st) < 0) {
			if (errno != ENOENT)
				i_error("lstat(%s) failed: %m", str_c(str));
			continue;
		}
		if (!S_ISSOCK(st.st_mode))
			continue;

		/* try to avoid unlinking sockets if someone's already
		   listening in them. do this only at startup, because
		   when SIGHUPing a child process might catch the new
		   connection before it notices that it's supposed
		   to die. null_fd == -1 check is a bit kludgy, but works.. */
		if (null_fd == -1) {
			int fd = net_connect_unix(str_c(str));
			if (fd != -1 || errno != ECONNREFUSED) {
				i_fatal("Dovecot is already running? "
					"Socket already exists: %s",
					str_c(str));
			}
		}

		if (unlink(str_c(str)) < 0 && errno != ENOENT)
			i_error("unlink(%s) failed: %m", str_c(str));
	}
	(void)closedir(dirp);
}

bool master_settings_do_fixes(const struct master_settings *set)
{
	const char *login_dir, *empty_dir;
	struct stat st;
	gid_t gid;

	/* since base dir is under /var/run by default, it may have been
	   deleted. */
	if (mkdir_parents(set->base_dir, 0755) < 0 && errno != EEXIST) {
		i_error("mkdir(%s) failed: %m", set->base_dir);
		return FALSE;
	}
	/* allow base_dir to be a symlink, so don't use lstat() */
	if (stat(set->base_dir, &st) < 0) {
		i_error("stat(%s) failed: %m", set->base_dir);
		return FALSE;
	}
	if (!S_ISDIR(st.st_mode)) {
		i_error("%s is not a directory", set->base_dir);
		return FALSE;
	}
	if ((st.st_mode & 0755) != 0755) {
		i_warning("Fixing permissions of %s to be world-readable",
			  set->base_dir);
		if (chmod(set->base_dir, 0755) < 0)
			i_error("chmod(%s) failed: %m", set->base_dir);
	}

	/* Make sure our permanent state directory exists */
	if (mkdir_parents(PKG_STATEDIR, 0750) < 0 && errno != EEXIST) {
		i_error("mkdir(%s) failed: %m", PKG_STATEDIR);
		return FALSE;
	}

	login_dir = t_strconcat(set->base_dir, "/login", NULL);
	if (settings_have_auth_unix_listeners_in(set, login_dir)) {
		/* we are not using external authentication, so make sure the
		   login directory exists with correct permissions and it's
		   empty. with external auth we wouldn't want to delete
		   existing sockets or break the permissions required by the
		   auth server. */
		mode_t mode = login_want_core_dumps(set, &gid) ? 0770 : 0750;
		if (safe_mkdir(login_dir, mode, master_uid, gid) == 0) {
			i_warning("Corrected permissions for login directory "
				  "%s", login_dir);
		}

		unlink_sockets(login_dir, "");
	} else {
		/* still make sure that login directory exists */
		if (mkdir(login_dir, 0755) < 0 && errno != EEXIST) {
			i_error("mkdir(%s) failed: %m", login_dir);
			return FALSE;
		}
	}

	empty_dir = t_strconcat(set->base_dir, "/empty", NULL);
	if (safe_mkdir(empty_dir, 0755, master_uid, getegid()) == 0) {
		i_warning("Corrected permissions for empty directory "
			  "%s", empty_dir);
	}
	return TRUE;
}