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