[thirdparty/systemd.git] / src / login / user-runtime-dir.c

/* SPDX-License-Identifier: LGPL-2.1+ */

#include <stdint.h>
#include <sys/mount.h>

#include "sd-bus.h"

#include "bus-error.h"
#include "fs-util.h"
#include "format-util.h"
#include "label.h"
#include "main-func.h"
#include "mkdir.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "selinux-util.h"
#include "smack-util.h"
#include "stdio-util.h"
#include "string-util.h"
#include "strv.h"
#include "user-util.h"

static int acquire_runtime_dir_size(uint64_t *ret) {
        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
        int r;

        r = sd_bus_default_system(&bus);
        if (r < 0)
                return log_error_errno(r, "Failed to connect to system bus: %m");

        r = sd_bus_get_property_trivial(bus, "org.freedesktop.login1", "/org/freedesktop/login1", "org.freedesktop.login1.Manager", "RuntimeDirectorySize", &error, 't', ret);
        if (r < 0)
                return log_error_errno(r, "Failed to acquire runtime directory size: %s", bus_error_message(&error, r));

        return 0;
}

static int user_mkdir_runtime_path(
                const char *runtime_path,
                uid_t uid,
                gid_t gid,
                uint64_t runtime_dir_size) {

        int r;

        assert(runtime_path);
        assert(path_is_absolute(runtime_path));
        assert(uid_is_valid(uid));
        assert(gid_is_valid(gid));

        r = mkdir_safe_label("/run/user", 0755, 0, 0, MKDIR_WARN_MODE);
        if (r < 0)
                return log_error_errno(r, "Failed to create /run/user: %m");

        if (path_is_mount_point(runtime_path, NULL, 0) >= 0)
                log_debug("%s is already a mount point", runtime_path);
        else {
                char options[sizeof("mode=0700,uid=,gid=,size=,smackfsroot=*")
                             + DECIMAL_STR_MAX(uid_t)
                             + DECIMAL_STR_MAX(gid_t)
                             + DECIMAL_STR_MAX(uint64_t)];

                xsprintf(options,
                         "mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%" PRIu64 "%s",
                         uid, gid, runtime_dir_size,
                         mac_smack_use() ? ",smackfsroot=*" : "");

                (void) mkdir_label(runtime_path, 0700);

                r = mount("tmpfs", runtime_path, "tmpfs", MS_NODEV|MS_NOSUID, options);
                if (r < 0) {
                        if (!IN_SET(errno, EPERM, EACCES)) {
                                r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", runtime_path);
                                goto fail;
                        }

                        log_debug_errno(errno, "Failed to mount per-user tmpfs directory %s.\n"
                                        "Assuming containerized execution, ignoring: %m", runtime_path);

                        r = chmod_and_chown(runtime_path, 0700, uid, gid);
                        if (r < 0) {
                                log_error_errno(r, "Failed to change ownership and mode of \"%s\": %m", runtime_path);
                                goto fail;
                        }
                }

                r = label_fix(runtime_path, 0);
                if (r < 0)
                        log_warning_errno(r, "Failed to fix label of \"%s\", ignoring: %m", runtime_path);
        }

        return 0;

fail:
        /* Try to clean up, but ignore errors */
        (void) rmdir(runtime_path);
        return r;
}

static int user_remove_runtime_path(const char *runtime_path) {
        int r;

        assert(runtime_path);
        assert(path_is_absolute(runtime_path));

        r = rm_rf(runtime_path, 0);
        if (r < 0)
                log_debug_errno(r, "Failed to remove runtime directory %s (before unmounting), ignoring: %m", runtime_path);

        /* Ignore cases where the directory isn't mounted, as that's quite possible, if we lacked the permissions to
         * mount something */
        r = umount2(runtime_path, MNT_DETACH);
        if (r < 0 && !IN_SET(errno, EINVAL, ENOENT))
                log_debug_errno(errno, "Failed to unmount user runtime directory %s, ignoring: %m", runtime_path);

        r = rm_rf(runtime_path, REMOVE_ROOT);
        if (r < 0 && r != -ENOENT)
                return log_error_errno(r, "Failed to remove runtime directory %s (after unmounting): %m", runtime_path);

        return 0;
}

static int do_mount(const char *user) {
        char runtime_path[sizeof("/run/user") + DECIMAL_STR_MAX(uid_t)];
        uint64_t runtime_dir_size;
        uid_t uid;
        gid_t gid;
        int r;

        r = get_user_creds(&user, &uid, &gid, NULL, NULL, 0);
        if (r < 0)
                return log_error_errno(r,
                                       r == -ESRCH ? "No such user \"%s\"" :
                                       r == -ENOMSG ? "UID \"%s\" is invalid or has an invalid main group"
                                                    : "Failed to look up user \"%s\": %m",
                                       user);

        r = acquire_runtime_dir_size(&runtime_dir_size);
        if (r < 0)
                return r;

        xsprintf(runtime_path, "/run/user/" UID_FMT, uid);

        log_debug("Will mount %s owned by "UID_FMT":"GID_FMT, runtime_path, uid, gid);
        return user_mkdir_runtime_path(runtime_path, uid, gid, runtime_dir_size);
}

static int do_umount(const char *user) {
        char runtime_path[sizeof("/run/user") + DECIMAL_STR_MAX(uid_t)];
        uid_t uid;
        int r;

        /* The user may be already removed. So, first try to parse the string by parse_uid(),
         * and if it fails, fallback to get_user_creds().*/
        if (parse_uid(user, &uid) < 0) {
                r = get_user_creds(&user, &uid, NULL, NULL, NULL, 0);
                if (r < 0)
                        return log_error_errno(r,
                                               r == -ESRCH ? "No such user \"%s\"" :
                                               r == -ENOMSG ? "UID \"%s\" is invalid or has an invalid main group"
                                                            : "Failed to look up user \"%s\": %m",
                                               user);
        }

        xsprintf(runtime_path, "/run/user/" UID_FMT, uid);

        log_debug("Will remove %s", runtime_path);
        return user_remove_runtime_path(runtime_path);
}

static int run(int argc, char *argv[]) {
        int r;

        log_parse_environment();
        log_open();

        if (argc != 3)
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "This program takes two arguments.");
        if (!STR_IN_SET(argv[1], "start", "stop"))
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "First argument must be either \"start\" or \"stop\".");

        r = mac_selinux_init();
        if (r < 0)
                return log_error_errno(r, "Could not initialize labelling: %m\n");

        umask(0022);

        if (streq(argv[1], "start"))
                return do_mount(argv[2]);
        if (streq(argv[1], "stop"))
                return do_umount(argv[2]);
        assert_not_reached("Unknown verb!");
}

DEFINE_MAIN_FUNCTION(run);
Commit	Line	Data
a9f0f5e5 ZJS	1	/* SPDX-License-Identifier: LGPL-2.1+ */
	2
	3	#include <stdint.h>
	4	#include <sys/mount.h>
	5
07ee5adb LP	6	#include "sd-bus.h"
	7
	8	#include "bus-error.h"
a9f0f5e5	9	#include "fs-util.h"
ca78ad1d	10	#include "format-util.h"
a9f0f5e5	11	#include "label.h"
5e332028	12	#include "main-func.h"
a9f0f5e5	13	#include "mkdir.h"
049af8ad	14	#include "mountpoint-util.h"
a9f0f5e5 ZJS	15	#include "path-util.h"
a9f0f5e5 ZJS	16	#include "rm-rf.h"
81375d80	17	#include "selinux-util.h"
a9f0f5e5 ZJS	18	#include "smack-util.h"
	19	#include "stdio-util.h"
	20	#include "string-util.h"
	21	#include "strv.h"
	22	#include "user-util.h"
	23
07ee5adb LP	24	static int acquire_runtime_dir_size(uint64_t *ret) {
07ee5adb LP	25	_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
92e31da1	26	_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
a9f0f5e5 ZJS	27	int r;
a9f0f5e5 ZJS	28
07ee5adb LP	29	r = sd_bus_default_system(&bus);
	30	if (r < 0)
	31	return log_error_errno(r, "Failed to connect to system bus: %m");
a9f0f5e5	32
07ee5adb	33	r = sd_bus_get_property_trivial(bus, "org.freedesktop.login1", "/org/freedesktop/login1", "org.freedesktop.login1.Manager", "RuntimeDirectorySize", &error, 't', ret);
a9f0f5e5	34	if (r < 0)
07ee5adb	35	return log_error_errno(r, "Failed to acquire runtime directory size: %s", bus_error_message(&error, r));
a9f0f5e5	36
a9f0f5e5 ZJS	37	return 0;
	38	}
	39
07ee5adb LP	40	static int user_mkdir_runtime_path(
	41	const char *runtime_path,
	42	uid_t uid,
	43	gid_t gid,
	44	uint64_t runtime_dir_size) {
	45
a9f0f5e5 ZJS	46	int r;
	47
	48	assert(runtime_path);
	49	assert(path_is_absolute(runtime_path));
	50	assert(uid_is_valid(uid));
	51	assert(gid_is_valid(gid));
	52
	53	r = mkdir_safe_label("/run/user", 0755, 0, 0, MKDIR_WARN_MODE);
	54	if (r < 0)
	55	return log_error_errno(r, "Failed to create /run/user: %m");
	56
	57	if (path_is_mount_point(runtime_path, NULL, 0) >= 0)
	58	log_debug("%s is already a mount point", runtime_path);
	59	else {
	60	char options[sizeof("mode=0700,uid=,gid=,size=,smackfsroot=*")
	61	+ DECIMAL_STR_MAX(uid_t)
	62	+ DECIMAL_STR_MAX(gid_t)
07ee5adb	63	+ DECIMAL_STR_MAX(uint64_t)];
a9f0f5e5 ZJS	64
a9f0f5e5 ZJS	65	xsprintf(options,
07ee5adb	66	"mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%" PRIu64 "%s",
a9f0f5e5 ZJS	67	uid, gid, runtime_dir_size,
	68	mac_smack_use() ? ",smackfsroot=*" : "");
	69
	70	(void) mkdir_label(runtime_path, 0700);
	71
	72	r = mount("tmpfs", runtime_path, "tmpfs", MS_NODEV\|MS_NOSUID, options);
	73	if (r < 0) {
	74	if (!IN_SET(errno, EPERM, EACCES)) {
	75	r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", runtime_path);
	76	goto fail;
	77	}
	78
	79	log_debug_errno(errno, "Failed to mount per-user tmpfs directory %s.\n"
	80	"Assuming containerized execution, ignoring: %m", runtime_path);
	81
	82	r = chmod_and_chown(runtime_path, 0700, uid, gid);
	83	if (r < 0) {
	84	log_error_errno(r, "Failed to change ownership and mode of \"%s\": %m", runtime_path);
	85	goto fail;
	86	}
	87	}
	88
	89	r = label_fix(runtime_path, 0);
	90	if (r < 0)
	91	log_warning_errno(r, "Failed to fix label of \"%s\", ignoring: %m", runtime_path);
	92	}
	93
	94	return 0;
	95
	96	fail:
	97	/* Try to clean up, but ignore errors */
	98	(void) rmdir(runtime_path);
	99	return r;
	100	}
	101
	102	static int user_remove_runtime_path(const char *runtime_path) {
	103	int r;
	104
	105	assert(runtime_path);
	106	assert(path_is_absolute(runtime_path));
	107
	108	r = rm_rf(runtime_path, 0);
	109	if (r < 0)
3a13442b	110	log_debug_errno(r, "Failed to remove runtime directory %s (before unmounting), ignoring: %m", runtime_path);
a9f0f5e5	111
3a13442b LP	112	/* Ignore cases where the directory isn't mounted, as that's quite possible, if we lacked the permissions to
3a13442b LP	113	* mount something */
a9f0f5e5 ZJS	114	r = umount2(runtime_path, MNT_DETACH);
a9f0f5e5 ZJS	115	if (r < 0 && !IN_SET(errno, EINVAL, ENOENT))
3a13442b	116	log_debug_errno(errno, "Failed to unmount user runtime directory %s, ignoring: %m", runtime_path);
a9f0f5e5 ZJS	117
a9f0f5e5 ZJS	118	r = rm_rf(runtime_path, REMOVE_ROOT);
3a13442b LP	119	if (r < 0 && r != -ENOENT)
3a13442b LP	120	return log_error_errno(r, "Failed to remove runtime directory %s (after unmounting): %m", runtime_path);
a9f0f5e5	121
3a13442b	122	return 0;
a9f0f5e5 ZJS	123	}
a9f0f5e5 ZJS	124
86d18f3b YW	125	static int do_mount(const char *user) {
86d18f3b YW	126	char runtime_path[sizeof("/run/user") + DECIMAL_STR_MAX(uid_t)];
07ee5adb	127	uint64_t runtime_dir_size;
86d18f3b YW	128	uid_t uid;
	129	gid_t gid;
	130	int r;
	131
fafff8f1	132	r = get_user_creds(&user, &uid, &gid, NULL, NULL, 0);
86d18f3b YW	133	if (r < 0)
	134	return log_error_errno(r,
	135	r == -ESRCH ? "No such user \"%s\"" :
	136	r == -ENOMSG ? "UID \"%s\" is invalid or has an invalid main group"
	137	: "Failed to look up user \"%s\": %m",
	138	user);
	139
07ee5adb LP	140	r = acquire_runtime_dir_size(&runtime_dir_size);
	141	if (r < 0)
	142	return r;
a9f0f5e5	143
07ee5adb	144	xsprintf(runtime_path, "/run/user/" UID_FMT, uid);
a9f0f5e5 ZJS	145
	146	log_debug("Will mount %s owned by "UID_FMT":"GID_FMT, runtime_path, uid, gid);
	147	return user_mkdir_runtime_path(runtime_path, uid, gid, runtime_dir_size);
	148	}
	149
86d18f3b YW	150	static int do_umount(const char *user) {
	151	char runtime_path[sizeof("/run/user") + DECIMAL_STR_MAX(uid_t)];
	152	uid_t uid;
	153	int r;
	154
	155	/* The user may be already removed. So, first try to parse the string by parse_uid(),
	156	* and if it fails, fallback to get_user_creds().*/
	157	if (parse_uid(user, &uid) < 0) {
fafff8f1	158	r = get_user_creds(&user, &uid, NULL, NULL, NULL, 0);
86d18f3b YW	159	if (r < 0)
	160	return log_error_errno(r,
	161	r == -ESRCH ? "No such user \"%s\"" :
	162	r == -ENOMSG ? "UID \"%s\" is invalid or has an invalid main group"
	163	: "Failed to look up user \"%s\": %m",
	164	user);
	165	}
	166
	167	xsprintf(runtime_path, "/run/user/" UID_FMT, uid);
	168
a9f0f5e5 ZJS	169	log_debug("Will remove %s", runtime_path);
	170	return user_remove_runtime_path(runtime_path);
	171	}
	172
cc639ee7	173	static int run(int argc, char *argv[]) {
a9f0f5e5 ZJS	174	int r;
	175
	176	log_parse_environment();
	177	log_open();
	178
baaa35ad ZJS	179	if (argc != 3)
	180	return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
	181	"This program takes two arguments.");
	182	if (!STR_IN_SET(argv[1], "start", "stop"))
	183	return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
	184	"First argument must be either \"start\" or \"stop\".");
a9f0f5e5	185
81375d80	186	r = mac_selinux_init();
cc639ee7 ZJS	187	if (r < 0)
cc639ee7 ZJS	188	return log_error_errno(r, "Could not initialize labelling: %m\n");
81375d80	189
a9f0f5e5 ZJS	190	umask(0022);
a9f0f5e5 ZJS	191
a9f0f5e5	192	if (streq(argv[1], "start"))
cc639ee7 ZJS	193	return do_mount(argv[2]);
	194	if (streq(argv[1], "stop"))
	195	return do_umount(argv[2]);
	196	assert_not_reached("Unknown verb!");
a9f0f5e5	197	}
cc639ee7 ZJS	198
cc639ee7 ZJS	199	DEFINE_MAIN_FUNCTION(run);