1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
3 #include <sys/eventfd.h>
9 #include <security/pam_appl.h>
10 #include <security/pam_misc.h>
14 #include <sys/apparmor.h>
17 #include "sd-messages.h"
20 #include "apparmor-util.h"
22 #include "argv-util.h"
24 #include "bpf-dlopen.h"
26 #include "btrfs-util.h"
27 #include "capability-util.h"
28 #include "cgroup-setup.h"
30 #include "chattr-util.h"
31 #include "chown-recursive.h"
33 #include "data-fd-util.h"
36 #include "exec-credential.h"
37 #include "exec-invoke.h"
39 #include "exit-status.h"
41 #include "hexdecoct.h"
43 #include "iovec-util.h"
44 #include "missing_ioprio.h"
45 #include "missing_prctl.h"
46 #include "missing_securebits.h"
47 #include "missing_syscall.h"
48 #include "mkdir-label.h"
49 #include "proc-cmdline.h"
50 #include "process-util.h"
52 #include "rlimit-util.h"
53 #include "seccomp-util.h"
54 #include "selinux-util.h"
55 #include "signal-util.h"
56 #include "smack-util.h"
57 #include "socket-util.h"
58 #include "string-table.h"
60 #include "terminal-util.h"
61 #include "utmp-wtmp.h"
64 #define IDLE_TIMEOUT_USEC (5*USEC_PER_SEC)
65 #define IDLE_TIMEOUT2_USEC (1*USEC_PER_SEC)
67 #define SNDBUF_SIZE (8*1024*1024)
69 static int shift_fds(int fds
[], size_t n_fds
) {
73 /* Modifies the fds array! (sorts it) */
77 for (int start
= 0;;) {
78 int restart_from
= -1;
80 for (int i
= start
; i
< (int) n_fds
; i
++) {
83 /* Already at right index? */
87 nfd
= fcntl(fds
[i
], F_DUPFD
, i
+ 3);
94 /* Hmm, the fd we wanted isn't free? Then
95 * let's remember that and try again from here */
96 if (nfd
!= i
+3 && restart_from
< 0)
100 if (restart_from
< 0)
103 start
= restart_from
;
117 assert(fds
|| n_fds
== 0);
119 /* Drops/Sets O_NONBLOCK and FD_CLOEXEC from the file flags.
120 * O_NONBLOCK only applies to socket activation though. */
122 for (size_t i
= 0; i
< n_fds
; i
++) {
124 if (i
< n_socket_fds
) {
125 r
= fd_nonblock(fds
[i
], nonblock
);
130 /* We unconditionally drop FD_CLOEXEC from the fds,
131 * since after all we want to pass these fds to our
134 r
= fd_cloexec(fds
[i
], false);
142 static bool is_terminal_input(ExecInput i
) {
145 EXEC_INPUT_TTY_FORCE
,
146 EXEC_INPUT_TTY_FAIL
);
149 static bool is_terminal_output(ExecOutput o
) {
152 EXEC_OUTPUT_KMSG_AND_CONSOLE
,
153 EXEC_OUTPUT_JOURNAL_AND_CONSOLE
);
156 static bool is_kmsg_output(ExecOutput o
) {
159 EXEC_OUTPUT_KMSG_AND_CONSOLE
);
162 static bool exec_context_needs_term(const ExecContext
*c
) {
165 /* Return true if the execution context suggests we should set $TERM to something useful. */
167 if (is_terminal_input(c
->std_input
))
170 if (is_terminal_output(c
->std_output
))
173 if (is_terminal_output(c
->std_error
))
176 return !!c
->tty_path
;
179 static int open_null_as(int flags
, int nfd
) {
184 fd
= open("/dev/null", flags
|O_NOCTTY
);
188 return move_fd(fd
, nfd
, false);
191 static int connect_journal_socket(
193 const char *log_namespace
,
197 uid_t olduid
= UID_INVALID
;
198 gid_t oldgid
= GID_INVALID
;
203 strjoina("/run/systemd/journal.", log_namespace
, "/stdout") :
204 "/run/systemd/journal/stdout";
206 if (gid_is_valid(gid
)) {
209 if (setegid(gid
) < 0)
213 if (uid_is_valid(uid
)) {
216 if (seteuid(uid
) < 0) {
222 r
= connect_unix_path(fd
, AT_FDCWD
, j
);
224 /* If we fail to restore the uid or gid, things will likely fail later on. This should only happen if
225 an LSM interferes. */
227 if (uid_is_valid(uid
))
228 (void) seteuid(olduid
);
231 if (gid_is_valid(gid
))
232 (void) setegid(oldgid
);
237 static int connect_logger_as(
238 const ExecContext
*context
,
239 const ExecParameters
*params
,
246 _cleanup_close_
int fd
= -EBADF
;
251 assert(output
< _EXEC_OUTPUT_MAX
);
255 fd
= socket(AF_UNIX
, SOCK_STREAM
, 0);
259 r
= connect_journal_socket(fd
, context
->log_namespace
, uid
, gid
);
263 if (shutdown(fd
, SHUT_RD
) < 0)
266 (void) fd_inc_sndbuf(fd
, SNDBUF_SIZE
);
276 context
->syslog_identifier
?: ident
,
277 params
->flags
& EXEC_PASS_LOG_UNIT
? params
->unit_id
: "",
278 context
->syslog_priority
,
279 !!context
->syslog_level_prefix
,
281 is_kmsg_output(output
),
282 is_terminal_output(output
)) < 0)
285 return move_fd(TAKE_FD(fd
), nfd
, false);
288 static int open_terminal_as(const char *path
, int flags
, int nfd
) {
294 fd
= open_terminal(path
, flags
| O_NOCTTY
);
298 return move_fd(fd
, nfd
, false);
301 static int acquire_path(const char *path
, int flags
, mode_t mode
) {
302 _cleanup_close_
int fd
= -EBADF
;
307 if (IN_SET(flags
& O_ACCMODE
, O_WRONLY
, O_RDWR
))
310 fd
= open(path
, flags
|O_NOCTTY
, mode
);
314 if (errno
!= ENXIO
) /* ENXIO is returned when we try to open() an AF_UNIX file system socket on Linux */
317 /* So, it appears the specified path could be an AF_UNIX socket. Let's see if we can connect to it. */
319 fd
= socket(AF_UNIX
, SOCK_STREAM
, 0);
323 r
= connect_unix_path(fd
, AT_FDCWD
, path
);
324 if (IN_SET(r
, -ENOTSOCK
, -EINVAL
))
325 /* Propagate initial error if we get ENOTSOCK or EINVAL, i.e. we have indication that this
326 * wasn't an AF_UNIX socket after all */
331 if ((flags
& O_ACCMODE
) == O_RDONLY
)
332 r
= shutdown(fd
, SHUT_WR
);
333 else if ((flags
& O_ACCMODE
) == O_WRONLY
)
334 r
= shutdown(fd
, SHUT_RD
);
343 static int fixup_input(
344 const ExecContext
*context
,
346 bool apply_tty_stdin
) {
352 std_input
= context
->std_input
;
354 if (is_terminal_input(std_input
) && !apply_tty_stdin
)
355 return EXEC_INPUT_NULL
;
357 if (std_input
== EXEC_INPUT_SOCKET
&& socket_fd
< 0)
358 return EXEC_INPUT_NULL
;
360 if (std_input
== EXEC_INPUT_DATA
&& context
->stdin_data_size
== 0)
361 return EXEC_INPUT_NULL
;
366 static int fixup_output(ExecOutput output
, int socket_fd
) {
368 if (output
== EXEC_OUTPUT_SOCKET
&& socket_fd
< 0)
369 return EXEC_OUTPUT_INHERIT
;
374 static int setup_input(
375 const ExecContext
*context
,
376 const ExecParameters
*params
,
378 const int named_iofds
[static 3]) {
387 if (params
->stdin_fd
>= 0) {
388 if (dup2(params
->stdin_fd
, STDIN_FILENO
) < 0)
391 /* Try to make this the controlling tty, if it is a tty, and reset it */
392 if (isatty(STDIN_FILENO
)) {
393 (void) ioctl(STDIN_FILENO
, TIOCSCTTY
, context
->std_input
== EXEC_INPUT_TTY_FORCE
);
395 if (context
->tty_reset
)
396 (void) reset_terminal_fd(STDIN_FILENO
, /* switch_to_text= */ true);
398 (void) exec_context_apply_tty_size(context
, STDIN_FILENO
, /* tty_path= */ NULL
);
404 i
= fixup_input(context
, socket_fd
, params
->flags
& EXEC_APPLY_TTY_STDIN
);
408 case EXEC_INPUT_NULL
:
409 return open_null_as(O_RDONLY
, STDIN_FILENO
);
412 case EXEC_INPUT_TTY_FORCE
:
413 case EXEC_INPUT_TTY_FAIL
: {
414 _cleanup_close_
int tty_fd
= -EBADF
;
415 const char *tty_path
;
417 tty_path
= ASSERT_PTR(exec_context_tty_path(context
));
419 tty_fd
= acquire_terminal(tty_path
,
420 i
== EXEC_INPUT_TTY_FAIL
? ACQUIRE_TERMINAL_TRY
:
421 i
== EXEC_INPUT_TTY_FORCE
? ACQUIRE_TERMINAL_FORCE
:
422 ACQUIRE_TERMINAL_WAIT
,
427 r
= exec_context_apply_tty_size(context
, tty_fd
, tty_path
);
431 r
= move_fd(tty_fd
, STDIN_FILENO
, /* cloexec= */ false);
439 case EXEC_INPUT_SOCKET
:
440 assert(socket_fd
>= 0);
442 return RET_NERRNO(dup2(socket_fd
, STDIN_FILENO
));
444 case EXEC_INPUT_NAMED_FD
:
445 assert(named_iofds
[STDIN_FILENO
] >= 0);
447 (void) fd_nonblock(named_iofds
[STDIN_FILENO
], false);
448 return RET_NERRNO(dup2(named_iofds
[STDIN_FILENO
], STDIN_FILENO
));
450 case EXEC_INPUT_DATA
: {
453 fd
= acquire_data_fd(context
->stdin_data
, context
->stdin_data_size
, 0);
457 return move_fd(fd
, STDIN_FILENO
, false);
460 case EXEC_INPUT_FILE
: {
464 assert(context
->stdio_file
[STDIN_FILENO
]);
466 rw
= (context
->std_output
== EXEC_OUTPUT_FILE
&& streq_ptr(context
->stdio_file
[STDIN_FILENO
], context
->stdio_file
[STDOUT_FILENO
])) ||
467 (context
->std_error
== EXEC_OUTPUT_FILE
&& streq_ptr(context
->stdio_file
[STDIN_FILENO
], context
->stdio_file
[STDERR_FILENO
]));
469 fd
= acquire_path(context
->stdio_file
[STDIN_FILENO
], rw
? O_RDWR
: O_RDONLY
, 0666 & ~context
->umask
);
473 return move_fd(fd
, STDIN_FILENO
, false);
477 assert_not_reached();
481 static bool can_inherit_stderr_from_stdout(
482 const ExecContext
*context
,
488 /* Returns true, if given the specified STDERR and STDOUT output we can directly dup() the stdout fd to the
491 if (e
== EXEC_OUTPUT_INHERIT
)
496 if (e
== EXEC_OUTPUT_NAMED_FD
)
497 return streq_ptr(context
->stdio_fdname
[STDOUT_FILENO
], context
->stdio_fdname
[STDERR_FILENO
]);
499 if (IN_SET(e
, EXEC_OUTPUT_FILE
, EXEC_OUTPUT_FILE_APPEND
, EXEC_OUTPUT_FILE_TRUNCATE
))
500 return streq_ptr(context
->stdio_file
[STDOUT_FILENO
], context
->stdio_file
[STDERR_FILENO
]);
505 static int setup_output(
506 const ExecContext
*context
,
507 const ExecParameters
*params
,
510 const int named_iofds
[static 3],
514 dev_t
*journal_stream_dev
,
515 ino_t
*journal_stream_ino
) {
524 assert(journal_stream_dev
);
525 assert(journal_stream_ino
);
527 if (fileno
== STDOUT_FILENO
&& params
->stdout_fd
>= 0) {
529 if (dup2(params
->stdout_fd
, STDOUT_FILENO
) < 0)
532 return STDOUT_FILENO
;
535 if (fileno
== STDERR_FILENO
&& params
->stderr_fd
>= 0) {
536 if (dup2(params
->stderr_fd
, STDERR_FILENO
) < 0)
539 return STDERR_FILENO
;
542 i
= fixup_input(context
, socket_fd
, params
->flags
& EXEC_APPLY_TTY_STDIN
);
543 o
= fixup_output(context
->std_output
, socket_fd
);
545 if (fileno
== STDERR_FILENO
) {
547 e
= fixup_output(context
->std_error
, socket_fd
);
549 /* This expects the input and output are already set up */
551 /* Don't change the stderr file descriptor if we inherit all
552 * the way and are not on a tty */
553 if (e
== EXEC_OUTPUT_INHERIT
&&
554 o
== EXEC_OUTPUT_INHERIT
&&
555 i
== EXEC_INPUT_NULL
&&
556 !is_terminal_input(context
->std_input
) &&
560 /* Duplicate from stdout if possible */
561 if (can_inherit_stderr_from_stdout(context
, o
, e
))
562 return RET_NERRNO(dup2(STDOUT_FILENO
, fileno
));
566 } else if (o
== EXEC_OUTPUT_INHERIT
) {
567 /* If input got downgraded, inherit the original value */
568 if (i
== EXEC_INPUT_NULL
&& is_terminal_input(context
->std_input
))
569 return open_terminal_as(exec_context_tty_path(context
), O_WRONLY
, fileno
);
571 /* If the input is connected to anything that's not a /dev/null or a data fd, inherit that... */
572 if (!IN_SET(i
, EXEC_INPUT_NULL
, EXEC_INPUT_DATA
))
573 return RET_NERRNO(dup2(STDIN_FILENO
, fileno
));
575 /* If we are not started from PID 1 we just inherit STDOUT from our parent process. */
579 /* We need to open /dev/null here anew, to get the right access mode. */
580 return open_null_as(O_WRONLY
, fileno
);
585 case EXEC_OUTPUT_NULL
:
586 return open_null_as(O_WRONLY
, fileno
);
588 case EXEC_OUTPUT_TTY
:
589 if (is_terminal_input(i
))
590 return RET_NERRNO(dup2(STDIN_FILENO
, fileno
));
592 /* We don't reset the terminal if this is just about output */
593 return open_terminal_as(exec_context_tty_path(context
), O_WRONLY
, fileno
);
595 case EXEC_OUTPUT_KMSG
:
596 case EXEC_OUTPUT_KMSG_AND_CONSOLE
:
597 case EXEC_OUTPUT_JOURNAL
:
598 case EXEC_OUTPUT_JOURNAL_AND_CONSOLE
:
599 r
= connect_logger_as(context
, params
, o
, ident
, fileno
, uid
, gid
);
601 log_exec_warning_errno(context
,
604 "Failed to connect %s to the journal socket, ignoring: %m",
605 fileno
== STDOUT_FILENO
? "stdout" : "stderr");
606 r
= open_null_as(O_WRONLY
, fileno
);
610 /* If we connected this fd to the journal via a stream, patch the device/inode into the passed
611 * parameters, but only then. This is useful so that we can set $JOURNAL_STREAM that permits
612 * services to detect whether they are connected to the journal or not.
614 * If both stdout and stderr are connected to a stream then let's make sure to store the data
615 * about STDERR as that's usually the best way to do logging. */
617 if (fstat(fileno
, &st
) >= 0 &&
618 (*journal_stream_ino
== 0 || fileno
== STDERR_FILENO
)) {
619 *journal_stream_dev
= st
.st_dev
;
620 *journal_stream_ino
= st
.st_ino
;
625 case EXEC_OUTPUT_SOCKET
:
626 assert(socket_fd
>= 0);
628 return RET_NERRNO(dup2(socket_fd
, fileno
));
630 case EXEC_OUTPUT_NAMED_FD
:
631 assert(named_iofds
[fileno
] >= 0);
633 (void) fd_nonblock(named_iofds
[fileno
], false);
634 return RET_NERRNO(dup2(named_iofds
[fileno
], fileno
));
636 case EXEC_OUTPUT_FILE
:
637 case EXEC_OUTPUT_FILE_APPEND
:
638 case EXEC_OUTPUT_FILE_TRUNCATE
: {
642 assert(context
->stdio_file
[fileno
]);
644 rw
= context
->std_input
== EXEC_INPUT_FILE
&&
645 streq_ptr(context
->stdio_file
[fileno
], context
->stdio_file
[STDIN_FILENO
]);
648 return RET_NERRNO(dup2(STDIN_FILENO
, fileno
));
651 if (o
== EXEC_OUTPUT_FILE_APPEND
)
653 else if (o
== EXEC_OUTPUT_FILE_TRUNCATE
)
656 fd
= acquire_path(context
->stdio_file
[fileno
], flags
, 0666 & ~context
->umask
);
660 return move_fd(fd
, fileno
, 0);
664 assert_not_reached();
668 static int chown_terminal(int fd
, uid_t uid
) {
673 /* Before we chown/chmod the TTY, let's ensure this is actually a tty */
674 if (!isatty_safe(fd
))
677 /* This might fail. What matters are the results. */
678 r
= fchmod_and_chown(fd
, TTY_MODE
, uid
, GID_INVALID
);
685 static int setup_confirm_stdio(
686 const ExecContext
*context
,
688 int *ret_saved_stdin
,
689 int *ret_saved_stdout
) {
691 _cleanup_close_
int fd
= -EBADF
, saved_stdin
= -EBADF
, saved_stdout
= -EBADF
;
694 assert(ret_saved_stdin
);
695 assert(ret_saved_stdout
);
697 saved_stdin
= fcntl(STDIN_FILENO
, F_DUPFD
, 3);
701 saved_stdout
= fcntl(STDOUT_FILENO
, F_DUPFD
, 3);
702 if (saved_stdout
< 0)
705 fd
= acquire_terminal(vc
, ACQUIRE_TERMINAL_WAIT
, DEFAULT_CONFIRM_USEC
);
709 r
= chown_terminal(fd
, getuid());
713 r
= reset_terminal_fd(fd
, /* switch_to_text= */ true);
717 r
= exec_context_apply_tty_size(context
, fd
, vc
);
721 r
= rearrange_stdio(fd
, fd
, STDERR_FILENO
); /* Invalidates 'fd' also on failure */
726 *ret_saved_stdin
= TAKE_FD(saved_stdin
);
727 *ret_saved_stdout
= TAKE_FD(saved_stdout
);
731 static void write_confirm_error_fd(int err
, int fd
, const char *unit_id
) {
735 if (err
== -ETIMEDOUT
)
736 dprintf(fd
, "Confirmation question timed out for %s, assuming positive response.\n", unit_id
);
739 dprintf(fd
, "Couldn't ask confirmation for %s: %m, assuming positive response.\n", unit_id
);
743 static void write_confirm_error(int err
, const char *vc
, const char *unit_id
) {
744 _cleanup_close_
int fd
= -EBADF
;
748 fd
= open_terminal(vc
, O_WRONLY
|O_NOCTTY
|O_CLOEXEC
);
752 write_confirm_error_fd(err
, fd
, unit_id
);
755 static int restore_confirm_stdio(int *saved_stdin
, int *saved_stdout
) {
759 assert(saved_stdout
);
763 if (*saved_stdin
>= 0)
764 if (dup2(*saved_stdin
, STDIN_FILENO
) < 0)
767 if (*saved_stdout
>= 0)
768 if (dup2(*saved_stdout
, STDOUT_FILENO
) < 0)
771 *saved_stdin
= safe_close(*saved_stdin
);
772 *saved_stdout
= safe_close(*saved_stdout
);
778 CONFIRM_PRETEND_FAILURE
= -1,
779 CONFIRM_PRETEND_SUCCESS
= 0,
783 static bool confirm_spawn_disabled(void) {
784 return access("/run/systemd/confirm_spawn_disabled", F_OK
) >= 0;
787 static int ask_for_confirmation(const ExecContext
*context
, const ExecParameters
*params
, const char *cmdline
) {
788 int saved_stdout
= -1, saved_stdin
= -1, r
;
789 _cleanup_free_
char *e
= NULL
;
795 /* For any internal errors, assume a positive response. */
796 r
= setup_confirm_stdio(context
, params
->confirm_spawn
, &saved_stdin
, &saved_stdout
);
798 write_confirm_error(r
, params
->confirm_spawn
, params
->unit_id
);
799 return CONFIRM_EXECUTE
;
802 /* confirm_spawn might have been disabled while we were sleeping. */
803 if (!params
->confirm_spawn
|| confirm_spawn_disabled()) {
808 e
= ellipsize(cmdline
, 60, 100);
816 r
= ask_char(&c
, "yfshiDjcn", "Execute %s? [y, f, s – h for help] ", e
);
818 write_confirm_error_fd(r
, STDOUT_FILENO
, params
->unit_id
);
825 printf("Resuming normal execution.\n");
826 manager_disable_confirm_spawn();
830 printf(" Unit: %s\n",
832 exec_context_dump(context
, stdout
, " ");
833 exec_params_dump(params
, stdout
, " ");
834 continue; /* ask again */
836 printf("Failing execution.\n");
837 r
= CONFIRM_PRETEND_FAILURE
;
840 printf(" c - continue, proceed without asking anymore\n"
841 " D - dump, show the state of the unit\n"
842 " f - fail, don't execute the command and pretend it failed\n"
844 " i - info, show a short summary of the unit\n"
845 " j - jobs, show jobs that are in progress\n"
846 " s - skip, don't execute the command and pretend it succeeded\n"
847 " y - yes, execute the command\n");
848 continue; /* ask again */
852 params
->unit_id
, cmdline
);
853 continue; /* ask again */
855 if (sigqueue(getppid(),
857 (const union sigval
) { .sival_int
= MANAGER_SIGNAL_COMMAND_DUMP_JOBS
}) < 0)
860 continue; /* ask again */
862 /* 'n' was removed in favor of 'f'. */
863 printf("Didn't understand 'n', did you mean 'f'?\n");
864 continue; /* ask again */
866 printf("Skipping execution.\n");
867 r
= CONFIRM_PRETEND_SUCCESS
;
873 assert_not_reached();
879 restore_confirm_stdio(&saved_stdin
, &saved_stdout
);
883 static int get_fixed_user(
884 const char *user_or_uid
,
885 const char **ret_username
,
888 const char **ret_home
,
889 const char **ret_shell
) {
894 assert(ret_username
);
896 /* Note that we don't set $HOME or $SHELL if they are not particularly enlightening anyway
897 * (i.e. are "/" or "/bin/nologin"). */
899 r
= get_user_creds(&user_or_uid
, ret_uid
, ret_gid
, ret_home
, ret_shell
, USER_CREDS_CLEAN
);
903 /* user_or_uid is normalized by get_user_creds to username */
904 *ret_username
= user_or_uid
;
909 static int get_fixed_group(
910 const char *group_or_gid
,
911 const char **ret_groupname
,
916 assert(group_or_gid
);
917 assert(ret_groupname
);
919 r
= get_group_creds(&group_or_gid
, ret_gid
, /* flags = */ 0);
923 /* group_or_gid is normalized by get_group_creds to groupname */
924 *ret_groupname
= group_or_gid
;
929 static int get_supplementary_groups(const ExecContext
*c
, const char *user
,
930 const char *group
, gid_t gid
,
931 gid_t
**supplementary_gids
, int *ngids
) {
934 bool keep_groups
= false;
935 gid_t
*groups
= NULL
;
936 _cleanup_free_ gid_t
*l_gids
= NULL
;
941 * If user is given, then lookup GID and supplementary groups list.
942 * We avoid NSS lookups for gid=0. Also we have to initialize groups
943 * here and as early as possible so we keep the list of supplementary
944 * groups of the caller.
946 if (user
&& gid_is_valid(gid
) && gid
!= 0) {
947 /* First step, initialize groups from /etc/groups */
948 if (initgroups(user
, gid
) < 0)
954 if (strv_isempty(c
->supplementary_groups
))
958 * If SupplementaryGroups= was passed then NGROUPS_MAX has to
959 * be positive, otherwise fail.
962 ngroups_max
= (int) sysconf(_SC_NGROUPS_MAX
);
963 if (ngroups_max
<= 0)
964 return errno_or_else(EOPNOTSUPP
);
966 l_gids
= new(gid_t
, ngroups_max
);
972 * Lookup the list of groups that the user belongs to, we
973 * avoid NSS lookups here too for gid=0.
976 if (getgrouplist(user
, gid
, l_gids
, &k
) < 0)
981 STRV_FOREACH(i
, c
->supplementary_groups
) {
984 if (k
>= ngroups_max
)
988 r
= get_group_creds(&g
, l_gids
+k
, 0);
996 * Sets ngids to zero to drop all supplementary groups, happens
997 * when we are under root and SupplementaryGroups= is empty.
1004 /* Otherwise get the final list of supplementary groups */
1005 groups
= memdup(l_gids
, sizeof(gid_t
) * k
);
1009 *supplementary_gids
= groups
;
1017 static int enforce_groups(gid_t gid
, const gid_t
*supplementary_gids
, int ngids
) {
1020 /* Handle SupplementaryGroups= if it is not empty */
1022 r
= maybe_setgroups(ngids
, supplementary_gids
);
1027 if (gid_is_valid(gid
)) {
1028 /* Then set our gids */
1029 if (setresgid(gid
, gid
, gid
) < 0)
1036 static int set_securebits(unsigned bits
, unsigned mask
) {
1040 current
= prctl(PR_GET_SECUREBITS
);
1044 /* Clear all securebits defined in mask and set bits */
1045 applied
= ((unsigned) current
& ~mask
) | bits
;
1046 if ((unsigned) current
== applied
)
1049 if (prctl(PR_SET_SECUREBITS
, applied
) < 0)
1055 static int enforce_user(
1056 const ExecContext
*context
,
1058 uint64_t capability_ambient_set
) {
1062 if (!uid_is_valid(uid
))
1065 /* Sets (but doesn't look up) the UIS and makes sure we keep the capabilities while doing so. For
1066 * setting secure bits the capability CAP_SETPCAP is required, so we also need keep-caps in this
1069 if ((capability_ambient_set
!= 0 || context
->secure_bits
!= 0) && uid
!= 0) {
1071 /* First step: If we need to keep capabilities but drop privileges we need to make sure we
1072 * keep our caps, while we drop privileges. Add KEEP_CAPS to the securebits */
1073 r
= set_securebits(1U << SECURE_KEEP_CAPS
, 0);
1078 /* Second step: actually set the uids */
1079 if (setresuid(uid
, uid
, uid
) < 0)
1082 /* At this point we should have all necessary capabilities but are otherwise a normal user. However,
1083 * the caps might got corrupted due to the setresuid() so we need clean them up later. This is done
1084 * outside of this call. */
1090 static int null_conv(
1092 const struct pam_message
**msg
,
1093 struct pam_response
**resp
,
1094 void *appdata_ptr
) {
1096 /* We don't support conversations */
1098 return PAM_CONV_ERR
;
1103 static int setup_pam(
1109 char ***env
, /* updated on success */
1110 const int fds
[], size_t n_fds
,
1115 static const struct pam_conv conv
= {
1120 _cleanup_(barrier_destroy
) Barrier barrier
= BARRIER_NULL
;
1121 _cleanup_strv_free_
char **e
= NULL
;
1122 pam_handle_t
*handle
= NULL
;
1124 int pam_code
= PAM_SUCCESS
, r
;
1125 bool close_session
= false;
1126 pid_t pam_pid
= 0, parent_pid
;
1133 /* We set up PAM in the parent process, then fork. The child
1134 * will then stay around until killed via PR_GET_PDEATHSIG or
1135 * systemd via the cgroup logic. It will then remove the PAM
1136 * session again. The parent process will exec() the actual
1137 * daemon. We do things this way to ensure that the main PID
1138 * of the daemon is the one we initially fork()ed. */
1140 r
= barrier_create(&barrier
);
1144 if (log_get_max_level() < LOG_DEBUG
)
1145 flags
|= PAM_SILENT
;
1147 pam_code
= pam_start(name
, user
, &conv
, &handle
);
1148 if (pam_code
!= PAM_SUCCESS
) {
1154 _cleanup_free_
char *q
= NULL
;
1156 /* Hmm, so no TTY was explicitly passed, but an fd passed to us directly might be a TTY. Let's figure
1157 * out if that's the case, and read the TTY off it. */
1159 if (getttyname_malloc(STDIN_FILENO
, &q
) >= 0)
1160 tty
= strjoina("/dev/", q
);
1164 pam_code
= pam_set_item(handle
, PAM_TTY
, tty
);
1165 if (pam_code
!= PAM_SUCCESS
)
1169 STRV_FOREACH(nv
, *env
) {
1170 pam_code
= pam_putenv(handle
, *nv
);
1171 if (pam_code
!= PAM_SUCCESS
)
1175 pam_code
= pam_acct_mgmt(handle
, flags
);
1176 if (pam_code
!= PAM_SUCCESS
)
1179 pam_code
= pam_setcred(handle
, PAM_ESTABLISH_CRED
| flags
);
1180 if (pam_code
!= PAM_SUCCESS
)
1181 log_debug("pam_setcred() failed, ignoring: %s", pam_strerror(handle
, pam_code
));
1183 pam_code
= pam_open_session(handle
, flags
);
1184 if (pam_code
!= PAM_SUCCESS
)
1187 close_session
= true;
1189 e
= pam_getenvlist(handle
);
1191 pam_code
= PAM_BUF_ERR
;
1195 /* Block SIGTERM, so that we know that it won't get lost in the child */
1197 assert_se(sigprocmask_many(SIG_BLOCK
, &old_ss
, SIGTERM
, -1) >= 0);
1199 parent_pid
= getpid_cached();
1201 r
= safe_fork("(sd-pam)", 0, &pam_pid
);
1207 /* The child's job is to reset the PAM session on termination */
1208 barrier_set_role(&barrier
, BARRIER_CHILD
);
1210 /* Make sure we don't keep open the passed fds in this child. We assume that otherwise only
1211 * those fds are open here that have been opened by PAM. */
1212 (void) close_many(fds
, n_fds
);
1214 /* Also close the 'exec_fd' in the child, since the service manager waits for the EOF induced
1215 * by the execve() to wait for completion, and if we'd keep the fd open here in the child
1216 * we'd never signal completion. */
1217 exec_fd
= safe_close(exec_fd
);
1219 /* Drop privileges - we don't need any to pam_close_session and this will make
1220 * PR_SET_PDEATHSIG work in most cases. If this fails, ignore the error - but expect sd-pam
1221 * threads to fail to exit normally */
1223 r
= fully_set_uid_gid(uid
, gid
, /* supplementary_gids= */ NULL
, /* n_supplementary_gids= */ 0);
1225 log_warning_errno(r
, "Failed to drop privileges in sd-pam: %m");
1227 (void) ignore_signals(SIGPIPE
);
1229 /* Wait until our parent died. This will only work if the above setresuid() succeeds,
1230 * otherwise the kernel will not allow unprivileged parents kill their privileged children
1231 * this way. We rely on the control groups kill logic to do the rest for us. */
1232 if (prctl(PR_SET_PDEATHSIG
, SIGTERM
) < 0)
1235 /* Tell the parent that our setup is done. This is especially important regarding dropping
1236 * privileges. Otherwise, unit setup might race against our setresuid(2) call.
1238 * If the parent aborted, we'll detect this below, hence ignore return failure here. */
1239 (void) barrier_place(&barrier
);
1241 /* Check if our parent process might already have died? */
1242 if (getppid() == parent_pid
) {
1246 assert_se(sigemptyset(&ss
) >= 0);
1247 assert_se(sigaddset(&ss
, SIGTERM
) >= 0);
1249 assert_se(sigwait(&ss
, &sig
) == 0);
1250 assert(sig
== SIGTERM
);
1253 pam_code
= pam_setcred(handle
, PAM_DELETE_CRED
| flags
);
1254 if (pam_code
!= PAM_SUCCESS
)
1257 /* If our parent died we'll end the session */
1258 if (getppid() != parent_pid
) {
1259 pam_code
= pam_close_session(handle
, flags
);
1260 if (pam_code
!= PAM_SUCCESS
)
1267 /* NB: pam_end() when called in child processes should set PAM_DATA_SILENT to let the module
1268 * know about this. See pam_end(3) */
1269 (void) pam_end(handle
, pam_code
| flags
| PAM_DATA_SILENT
);
1273 barrier_set_role(&barrier
, BARRIER_PARENT
);
1275 /* If the child was forked off successfully it will do all the cleanups, so forget about the handle
1279 /* Unblock SIGTERM again in the parent */
1280 assert_se(sigprocmask(SIG_SETMASK
, &old_ss
, NULL
) >= 0);
1282 /* We close the log explicitly here, since the PAM modules might have opened it, but we don't want
1283 * this fd around. */
1286 /* Synchronously wait for the child to initialize. We don't care for errors as we cannot
1287 * recover. However, warn loudly if it happens. */
1288 if (!barrier_place_and_sync(&barrier
))
1289 log_error("PAM initialization failed");
1291 return strv_free_and_replace(*env
, e
);
1294 if (pam_code
!= PAM_SUCCESS
) {
1295 log_error("PAM failed: %s", pam_strerror(handle
, pam_code
));
1296 r
= -EPERM
; /* PAM errors do not map to errno */
1298 log_error_errno(r
, "PAM failed: %m");
1302 pam_code
= pam_close_session(handle
, flags
);
1304 (void) pam_end(handle
, pam_code
| flags
);
1314 static void rename_process_from_path(const char *path
) {
1315 _cleanup_free_
char *buf
= NULL
;
1320 /* This resulting string must fit in 10 chars (i.e. the length of "/sbin/init") to look pretty in
1323 if (path_extract_filename(path
, &buf
) < 0) {
1324 rename_process("(...)");
1328 size_t l
= strlen(buf
);
1330 /* The end of the process name is usually more interesting, since the first bit might just be
1337 char process_name
[11];
1338 process_name
[0] = '(';
1339 memcpy(process_name
+1, p
, l
);
1340 process_name
[1+l
] = ')';
1341 process_name
[1+l
+1] = 0;
1343 (void) rename_process(process_name
);
1346 static bool context_has_address_families(const ExecContext
*c
) {
1349 return c
->address_families_allow_list
||
1350 !set_isempty(c
->address_families
);
1353 static bool context_has_syscall_filters(const ExecContext
*c
) {
1356 return c
->syscall_allow_list
||
1357 !hashmap_isempty(c
->syscall_filter
);
1360 static bool context_has_syscall_logs(const ExecContext
*c
) {
1363 return c
->syscall_log_allow_list
||
1364 !hashmap_isempty(c
->syscall_log
);
1367 static bool context_has_seccomp(const ExecContext
*c
) {
1368 /* We need NNP if we have any form of seccomp and are unprivileged */
1369 return c
->lock_personality
||
1370 c
->memory_deny_write_execute
||
1371 c
->private_devices
||
1373 c
->protect_hostname
||
1374 c
->protect_kernel_tunables
||
1375 c
->protect_kernel_modules
||
1376 c
->protect_kernel_logs
||
1377 context_has_address_families(c
) ||
1378 exec_context_restrict_namespaces_set(c
) ||
1379 c
->restrict_realtime
||
1380 c
->restrict_suid_sgid
||
1381 !set_isempty(c
->syscall_archs
) ||
1382 context_has_syscall_filters(c
) ||
1383 context_has_syscall_logs(c
);
1386 static bool context_has_no_new_privileges(const ExecContext
*c
) {
1389 if (c
->no_new_privileges
)
1392 if (have_effective_cap(CAP_SYS_ADMIN
) > 0) /* if we are privileged, we don't need NNP */
1395 return context_has_seccomp(c
);
1400 static bool seccomp_allows_drop_privileges(const ExecContext
*c
) {
1402 bool has_capget
= false, has_capset
= false, has_prctl
= false;
1406 /* No syscall filter, we are allowed to drop privileges */
1407 if (hashmap_isempty(c
->syscall_filter
))
1410 HASHMAP_FOREACH_KEY(val
, id
, c
->syscall_filter
) {
1411 _cleanup_free_
char *name
= NULL
;
1413 name
= seccomp_syscall_resolve_num_arch(SCMP_ARCH_NATIVE
, PTR_TO_INT(id
) - 1);
1415 if (streq(name
, "capget"))
1417 else if (streq(name
, "capset"))
1419 else if (streq(name
, "prctl"))
1423 if (c
->syscall_allow_list
)
1424 return has_capget
&& has_capset
&& has_prctl
;
1426 return !(has_capget
|| has_capset
|| has_prctl
);
1429 static bool skip_seccomp_unavailable(const ExecContext
*c
, const ExecParameters
*p
, const char* msg
) {
1431 if (is_seccomp_available())
1434 log_exec_debug(c
, p
, "SECCOMP features not detected in the kernel, skipping %s", msg
);
1438 static int apply_syscall_filter(const ExecContext
*c
, const ExecParameters
*p
, bool needs_ambient_hack
) {
1439 uint32_t negative_action
, default_action
, action
;
1445 if (!context_has_syscall_filters(c
))
1448 if (skip_seccomp_unavailable(c
, p
, "SystemCallFilter="))
1451 negative_action
= c
->syscall_errno
== SECCOMP_ERROR_NUMBER_KILL
? scmp_act_kill_process() : SCMP_ACT_ERRNO(c
->syscall_errno
);
1453 if (c
->syscall_allow_list
) {
1454 default_action
= negative_action
;
1455 action
= SCMP_ACT_ALLOW
;
1457 default_action
= SCMP_ACT_ALLOW
;
1458 action
= negative_action
;
1461 if (needs_ambient_hack
) {
1462 r
= seccomp_filter_set_add(c
->syscall_filter
, c
->syscall_allow_list
, syscall_filter_sets
+ SYSCALL_FILTER_SET_SETUID
);
1467 return seccomp_load_syscall_filter_set_raw(default_action
, c
->syscall_filter
, action
, false);
1470 static int apply_syscall_log(const ExecContext
*c
, const ExecParameters
*p
) {
1472 uint32_t default_action
, action
;
1478 if (!context_has_syscall_logs(c
))
1482 if (skip_seccomp_unavailable(c
, p
, "SystemCallLog="))
1485 if (c
->syscall_log_allow_list
) {
1486 /* Log nothing but the ones listed */
1487 default_action
= SCMP_ACT_ALLOW
;
1488 action
= SCMP_ACT_LOG
;
1490 /* Log everything but the ones listed */
1491 default_action
= SCMP_ACT_LOG
;
1492 action
= SCMP_ACT_ALLOW
;
1495 return seccomp_load_syscall_filter_set_raw(default_action
, c
->syscall_log
, action
, false);
1497 /* old libseccomp */
1498 log_exec_debug(c
, p
, "SECCOMP feature SCMP_ACT_LOG not available, skipping SystemCallLog=");
1503 static int apply_syscall_archs(const ExecContext
*c
, const ExecParameters
*p
) {
1507 if (set_isempty(c
->syscall_archs
))
1510 if (skip_seccomp_unavailable(c
, p
, "SystemCallArchitectures="))
1513 return seccomp_restrict_archs(c
->syscall_archs
);
1516 static int apply_address_families(const ExecContext
*c
, const ExecParameters
*p
) {
1520 if (!context_has_address_families(c
))
1523 if (skip_seccomp_unavailable(c
, p
, "RestrictAddressFamilies="))
1526 return seccomp_restrict_address_families(c
->address_families
, c
->address_families_allow_list
);
1529 static int apply_memory_deny_write_execute(const ExecContext
*c
, const ExecParameters
*p
) {
1535 if (!c
->memory_deny_write_execute
)
1538 /* use prctl() if kernel supports it (6.3) */
1539 r
= prctl(PR_SET_MDWE
, PR_MDWE_REFUSE_EXEC_GAIN
, 0, 0, 0);
1541 log_exec_debug(c
, p
, "Enabled MemoryDenyWriteExecute= with PR_SET_MDWE");
1544 if (r
< 0 && errno
!= EINVAL
)
1545 return log_exec_debug_errno(c
,
1548 "Failed to enable MemoryDenyWriteExecute= with PR_SET_MDWE: %m");
1549 /* else use seccomp */
1550 log_exec_debug(c
, p
, "Kernel doesn't support PR_SET_MDWE: falling back to seccomp");
1552 if (skip_seccomp_unavailable(c
, p
, "MemoryDenyWriteExecute="))
1555 return seccomp_memory_deny_write_execute();
1558 static int apply_restrict_realtime(const ExecContext
*c
, const ExecParameters
*p
) {
1562 if (!c
->restrict_realtime
)
1565 if (skip_seccomp_unavailable(c
, p
, "RestrictRealtime="))
1568 return seccomp_restrict_realtime();
1571 static int apply_restrict_suid_sgid(const ExecContext
*c
, const ExecParameters
*p
) {
1575 if (!c
->restrict_suid_sgid
)
1578 if (skip_seccomp_unavailable(c
, p
, "RestrictSUIDSGID="))
1581 return seccomp_restrict_suid_sgid();
1584 static int apply_protect_sysctl(const ExecContext
*c
, const ExecParameters
*p
) {
1588 /* Turn off the legacy sysctl() system call. Many distributions turn this off while building the kernel, but
1589 * let's protect even those systems where this is left on in the kernel. */
1591 if (!c
->protect_kernel_tunables
)
1594 if (skip_seccomp_unavailable(c
, p
, "ProtectKernelTunables="))
1597 return seccomp_protect_sysctl();
1600 static int apply_protect_kernel_modules(const ExecContext
*c
, const ExecParameters
*p
) {
1604 /* Turn off module syscalls on ProtectKernelModules=yes */
1606 if (!c
->protect_kernel_modules
)
1609 if (skip_seccomp_unavailable(c
, p
, "ProtectKernelModules="))
1612 return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW
, syscall_filter_sets
+ SYSCALL_FILTER_SET_MODULE
, SCMP_ACT_ERRNO(EPERM
), false);
1615 static int apply_protect_kernel_logs(const ExecContext
*c
, const ExecParameters
*p
) {
1619 if (!c
->protect_kernel_logs
)
1622 if (skip_seccomp_unavailable(c
, p
, "ProtectKernelLogs="))
1625 return seccomp_protect_syslog();
1628 static int apply_protect_clock(const ExecContext
*c
, const ExecParameters
*p
) {
1632 if (!c
->protect_clock
)
1635 if (skip_seccomp_unavailable(c
, p
, "ProtectClock="))
1638 return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW
, syscall_filter_sets
+ SYSCALL_FILTER_SET_CLOCK
, SCMP_ACT_ERRNO(EPERM
), false);
1641 static int apply_private_devices(const ExecContext
*c
, const ExecParameters
*p
) {
1645 /* If PrivateDevices= is set, also turn off iopl and all @raw-io syscalls. */
1647 if (!c
->private_devices
)
1650 if (skip_seccomp_unavailable(c
, p
, "PrivateDevices="))
1653 return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW
, syscall_filter_sets
+ SYSCALL_FILTER_SET_RAW_IO
, SCMP_ACT_ERRNO(EPERM
), false);
1656 static int apply_restrict_namespaces(const ExecContext
*c
, const ExecParameters
*p
) {
1660 if (!exec_context_restrict_namespaces_set(c
))
1663 if (skip_seccomp_unavailable(c
, p
, "RestrictNamespaces="))
1666 return seccomp_restrict_namespaces(c
->restrict_namespaces
);
1669 static int apply_lock_personality(const ExecContext
*c
, const ExecParameters
*p
) {
1670 unsigned long personality
;
1676 if (!c
->lock_personality
)
1679 if (skip_seccomp_unavailable(c
, p
, "LockPersonality="))
1682 personality
= c
->personality
;
1684 /* If personality is not specified, use either PER_LINUX or PER_LINUX32 depending on what is currently set. */
1685 if (personality
== PERSONALITY_INVALID
) {
1687 r
= opinionated_personality(&personality
);
1692 return seccomp_lock_personality(personality
);
1698 static int apply_restrict_filesystems(const ExecContext
*c
, const ExecParameters
*p
) {
1704 if (!exec_context_restrict_filesystems_set(c
))
1707 if (p
->bpf_outer_map_fd
< 0) {
1708 /* LSM BPF is unsupported or lsm_bpf_setup failed */
1709 log_exec_debug(c
, p
, "LSM BPF not supported, skipping RestrictFileSystems=");
1713 /* We are in a new binary, so dl-open again */
1718 return lsm_bpf_restrict_filesystems(c
->restrict_filesystems
, p
->cgroup_id
, p
->bpf_outer_map_fd
, c
->restrict_filesystems_allow_list
);
1722 static int apply_protect_hostname(const ExecContext
*c
, const ExecParameters
*p
, int *ret_exit_status
) {
1726 if (!c
->protect_hostname
)
1729 if (ns_type_supported(NAMESPACE_UTS
)) {
1730 if (unshare(CLONE_NEWUTS
) < 0) {
1731 if (!ERRNO_IS_NOT_SUPPORTED(errno
) && !ERRNO_IS_PRIVILEGE(errno
)) {
1732 *ret_exit_status
= EXIT_NAMESPACE
;
1733 return log_exec_error_errno(c
,
1736 "Failed to set up UTS namespacing: %m");
1741 "ProtectHostname=yes is configured, but UTS namespace setup is "
1742 "prohibited (container manager?), ignoring namespace setup.");
1747 "ProtectHostname=yes is configured, but the kernel does not "
1748 "support UTS namespaces, ignoring namespace setup.");
1753 if (skip_seccomp_unavailable(c
, p
, "ProtectHostname="))
1756 r
= seccomp_protect_hostname();
1758 *ret_exit_status
= EXIT_SECCOMP
;
1759 return log_exec_error_errno(c
, p
, r
, "Failed to apply hostname restrictions: %m");
1766 static void do_idle_pipe_dance(int idle_pipe
[static 4]) {
1769 idle_pipe
[1] = safe_close(idle_pipe
[1]);
1770 idle_pipe
[2] = safe_close(idle_pipe
[2]);
1772 if (idle_pipe
[0] >= 0) {
1775 r
= fd_wait_for_event(idle_pipe
[0], POLLHUP
, IDLE_TIMEOUT_USEC
);
1777 if (idle_pipe
[3] >= 0 && r
== 0 /* timeout */) {
1780 /* Signal systemd that we are bored and want to continue. */
1781 n
= write(idle_pipe
[3], "x", 1);
1783 /* Wait for systemd to react to the signal above. */
1784 (void) fd_wait_for_event(idle_pipe
[0], POLLHUP
, IDLE_TIMEOUT2_USEC
);
1787 idle_pipe
[0] = safe_close(idle_pipe
[0]);
1791 idle_pipe
[3] = safe_close(idle_pipe
[3]);
1794 static const char *exec_directory_env_name_to_string(ExecDirectoryType t
);
1796 /* And this table also maps ExecDirectoryType, to the environment variable we pass the selected directory to
1797 * the service payload in. */
1798 static const char* const exec_directory_env_name_table
[_EXEC_DIRECTORY_TYPE_MAX
] = {
1799 [EXEC_DIRECTORY_RUNTIME
] = "RUNTIME_DIRECTORY",
1800 [EXEC_DIRECTORY_STATE
] = "STATE_DIRECTORY",
1801 [EXEC_DIRECTORY_CACHE
] = "CACHE_DIRECTORY",
1802 [EXEC_DIRECTORY_LOGS
] = "LOGS_DIRECTORY",
1803 [EXEC_DIRECTORY_CONFIGURATION
] = "CONFIGURATION_DIRECTORY",
1806 DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(exec_directory_env_name
, ExecDirectoryType
);
1808 static int build_environment(
1809 const ExecContext
*c
,
1810 const ExecParameters
*p
,
1811 const CGroupContext
*cgroup_context
,
1814 const char *username
,
1816 dev_t journal_stream_dev
,
1817 ino_t journal_stream_ino
,
1818 const char *memory_pressure_path
,
1821 _cleanup_strv_free_
char **our_env
= NULL
;
1830 #define N_ENV_VARS 19
1831 our_env
= new0(char*, N_ENV_VARS
+ _EXEC_DIRECTORY_TYPE_MAX
);
1836 _cleanup_free_
char *joined
= NULL
;
1838 if (asprintf(&x
, "LISTEN_PID="PID_FMT
, getpid_cached()) < 0)
1840 our_env
[n_env
++] = x
;
1842 if (asprintf(&x
, "LISTEN_FDS=%zu", n_fds
) < 0)
1844 our_env
[n_env
++] = x
;
1846 joined
= strv_join(p
->fd_names
, ":");
1850 x
= strjoin("LISTEN_FDNAMES=", joined
);
1853 our_env
[n_env
++] = x
;
1856 if ((p
->flags
& EXEC_SET_WATCHDOG
) && p
->watchdog_usec
> 0) {
1857 if (asprintf(&x
, "WATCHDOG_PID="PID_FMT
, getpid_cached()) < 0)
1859 our_env
[n_env
++] = x
;
1861 if (asprintf(&x
, "WATCHDOG_USEC="USEC_FMT
, p
->watchdog_usec
) < 0)
1863 our_env
[n_env
++] = x
;
1866 /* If this is D-Bus, tell the nss-systemd module, since it relies on being able to use blocking
1867 * Varlink calls back to us for look up dynamic users in PID 1. Break the deadlock between D-Bus and
1868 * PID 1 by disabling use of PID1' NSS interface for looking up dynamic users. */
1869 if (p
->flags
& EXEC_NSS_DYNAMIC_BYPASS
) {
1870 x
= strdup("SYSTEMD_NSS_DYNAMIC_BYPASS=1");
1873 our_env
[n_env
++] = x
;
1876 /* We query "root" if this is a system unit and User= is not specified. $USER is always set. $HOME
1877 * could cause problem for e.g. getty, since login doesn't override $HOME, and $LOGNAME and $SHELL don't
1878 * really make much sense since we're not logged in. Hence we conditionalize the three based on
1879 * SetLoginEnvironment= switch. */
1880 if (!c
->user
&& !c
->dynamic_user
&& p
->runtime_scope
== RUNTIME_SCOPE_SYSTEM
) {
1881 r
= get_fixed_user("root", &username
, NULL
, NULL
, &home
, &shell
);
1883 return log_exec_debug_errno(c
,
1886 "Failed to determine user credentials for root: %m");
1889 bool set_user_login_env
= exec_context_get_set_login_environment(c
);
1892 x
= strjoin("USER=", username
);
1895 our_env
[n_env
++] = x
;
1897 if (set_user_login_env
) {
1898 x
= strjoin("LOGNAME=", username
);
1901 our_env
[n_env
++] = x
;
1905 if (home
&& set_user_login_env
) {
1906 x
= strjoin("HOME=", home
);
1910 path_simplify(x
+ 5);
1911 our_env
[n_env
++] = x
;
1914 if (shell
&& set_user_login_env
) {
1915 x
= strjoin("SHELL=", shell
);
1919 path_simplify(x
+ 6);
1920 our_env
[n_env
++] = x
;
1923 if (!sd_id128_is_null(p
->invocation_id
)) {
1924 assert(p
->invocation_id_string
);
1926 x
= strjoin("INVOCATION_ID=", p
->invocation_id_string
);
1930 our_env
[n_env
++] = x
;
1933 if (exec_context_needs_term(c
)) {
1934 _cleanup_free_
char *cmdline
= NULL
;
1935 const char *tty_path
, *term
= NULL
;
1937 tty_path
= exec_context_tty_path(c
);
1939 /* If we are forked off PID 1 and we are supposed to operate on /dev/console, then let's try
1940 * to inherit the $TERM set for PID 1. This is useful for containers so that the $TERM the
1941 * container manager passes to PID 1 ends up all the way in the console login shown. */
1943 if (path_equal_ptr(tty_path
, "/dev/console") && getppid() == 1)
1944 term
= getenv("TERM");
1945 else if (tty_path
&& in_charset(skip_dev_prefix(tty_path
), ALPHANUMERICAL
)) {
1946 _cleanup_free_
char *key
= NULL
;
1948 key
= strjoin("systemd.tty.term.", skip_dev_prefix(tty_path
));
1952 r
= proc_cmdline_get_key(key
, 0, &cmdline
);
1954 log_exec_debug_errno(c
,
1957 "Failed to read %s from kernel cmdline, ignoring: %m",
1964 term
= default_term_for_tty(tty_path
);
1966 x
= strjoin("TERM=", term
);
1969 our_env
[n_env
++] = x
;
1972 if (journal_stream_dev
!= 0 && journal_stream_ino
!= 0) {
1973 if (asprintf(&x
, "JOURNAL_STREAM=" DEV_FMT
":" INO_FMT
, journal_stream_dev
, journal_stream_ino
) < 0)
1976 our_env
[n_env
++] = x
;
1979 if (c
->log_namespace
) {
1980 x
= strjoin("LOG_NAMESPACE=", c
->log_namespace
);
1984 our_env
[n_env
++] = x
;
1987 for (ExecDirectoryType t
= 0; t
< _EXEC_DIRECTORY_TYPE_MAX
; t
++) {
1988 _cleanup_free_
char *joined
= NULL
;
1994 if (c
->directories
[t
].n_items
== 0)
1997 n
= exec_directory_env_name_to_string(t
);
2001 for (size_t i
= 0; i
< c
->directories
[t
].n_items
; i
++) {
2002 _cleanup_free_
char *prefixed
= NULL
;
2004 prefixed
= path_join(p
->prefix
[t
], c
->directories
[t
].items
[i
].path
);
2008 if (!strextend_with_separator(&joined
, ":", prefixed
))
2012 x
= strjoin(n
, "=", joined
);
2016 our_env
[n_env
++] = x
;
2019 _cleanup_free_
char *creds_dir
= NULL
;
2020 r
= exec_context_get_credential_directory(c
, p
, p
->unit_id
, &creds_dir
);
2024 x
= strjoin("CREDENTIALS_DIRECTORY=", creds_dir
);
2028 our_env
[n_env
++] = x
;
2031 if (asprintf(&x
, "SYSTEMD_EXEC_PID=" PID_FMT
, getpid_cached()) < 0)
2034 our_env
[n_env
++] = x
;
2036 if (memory_pressure_path
) {
2037 x
= strjoin("MEMORY_PRESSURE_WATCH=", memory_pressure_path
);
2041 our_env
[n_env
++] = x
;
2043 if (cgroup_context
&& !path_equal(memory_pressure_path
, "/dev/null")) {
2044 _cleanup_free_
char *b
= NULL
, *e
= NULL
;
2046 if (asprintf(&b
, "%s " USEC_FMT
" " USEC_FMT
,
2047 MEMORY_PRESSURE_DEFAULT_TYPE
,
2048 cgroup_context
->memory_pressure_threshold_usec
== USEC_INFINITY
? MEMORY_PRESSURE_DEFAULT_THRESHOLD_USEC
:
2049 CLAMP(cgroup_context
->memory_pressure_threshold_usec
, 1U, MEMORY_PRESSURE_DEFAULT_WINDOW_USEC
),
2050 MEMORY_PRESSURE_DEFAULT_WINDOW_USEC
) < 0)
2053 if (base64mem(b
, strlen(b
) + 1, &e
) < 0)
2056 x
= strjoin("MEMORY_PRESSURE_WRITE=", e
);
2060 our_env
[n_env
++] = x
;
2064 assert(n_env
< N_ENV_VARS
+ _EXEC_DIRECTORY_TYPE_MAX
);
2067 *ret
= TAKE_PTR(our_env
);
2072 static int build_pass_environment(const ExecContext
*c
, char ***ret
) {
2073 _cleanup_strv_free_
char **pass_env
= NULL
;
2076 STRV_FOREACH(i
, c
->pass_environment
) {
2077 _cleanup_free_
char *x
= NULL
;
2083 x
= strjoin(*i
, "=", v
);
2087 if (!GREEDY_REALLOC(pass_env
, n_env
+ 2))
2090 pass_env
[n_env
++] = TAKE_PTR(x
);
2091 pass_env
[n_env
] = NULL
;
2094 *ret
= TAKE_PTR(pass_env
);
2099 static int setup_private_users(uid_t ouid
, gid_t ogid
, uid_t uid
, gid_t gid
) {
2100 _cleanup_free_
char *uid_map
= NULL
, *gid_map
= NULL
;
2101 _cleanup_close_pair_
int errno_pipe
[2] = EBADF_PAIR
;
2102 _cleanup_close_
int unshare_ready_fd
= -EBADF
;
2103 _cleanup_(sigkill_waitp
) pid_t pid
= 0;
2108 /* Set up a user namespace and map the original UID/GID (IDs from before any user or group changes, i.e.
2109 * the IDs from the user or system manager(s)) to itself, the selected UID/GID to itself, and everything else to
2110 * nobody. In order to be able to write this mapping we need CAP_SETUID in the original user namespace, which
2111 * we however lack after opening the user namespace. To work around this we fork() a temporary child process,
2112 * which waits for the parent to create the new user namespace while staying in the original namespace. The
2113 * child then writes the UID mapping, under full privileges. The parent waits for the child to finish and
2114 * continues execution normally.
2115 * For unprivileged users (i.e. without capabilities), the root to root mapping is excluded. As such, it
2116 * does not need CAP_SETUID to write the single line mapping to itself. */
2118 /* Can only set up multiple mappings with CAP_SETUID. */
2119 if (have_effective_cap(CAP_SETUID
) > 0 && uid
!= ouid
&& uid_is_valid(uid
))
2120 r
= asprintf(&uid_map
,
2121 UID_FMT
" " UID_FMT
" 1\n" /* Map $OUID → $OUID */
2122 UID_FMT
" " UID_FMT
" 1\n", /* Map $UID → $UID */
2123 ouid
, ouid
, uid
, uid
);
2125 r
= asprintf(&uid_map
,
2126 UID_FMT
" " UID_FMT
" 1\n", /* Map $OUID → $OUID */
2132 /* Can only set up multiple mappings with CAP_SETGID. */
2133 if (have_effective_cap(CAP_SETGID
) > 0 && gid
!= ogid
&& gid_is_valid(gid
))
2134 r
= asprintf(&gid_map
,
2135 GID_FMT
" " GID_FMT
" 1\n" /* Map $OGID → $OGID */
2136 GID_FMT
" " GID_FMT
" 1\n", /* Map $GID → $GID */
2137 ogid
, ogid
, gid
, gid
);
2139 r
= asprintf(&gid_map
,
2140 GID_FMT
" " GID_FMT
" 1\n", /* Map $OGID -> $OGID */
2146 /* Create a communication channel so that the parent can tell the child when it finished creating the user
2148 unshare_ready_fd
= eventfd(0, EFD_CLOEXEC
);
2149 if (unshare_ready_fd
< 0)
2152 /* Create a communication channel so that the child can tell the parent a proper error code in case it
2154 if (pipe2(errno_pipe
, O_CLOEXEC
) < 0)
2157 r
= safe_fork("(sd-userns)", FORK_RESET_SIGNALS
|FORK_DEATHSIG_SIGKILL
, &pid
);
2161 _cleanup_close_
int fd
= -EBADF
;
2165 /* Child process, running in the original user namespace. Let's update the parent's UID/GID map from
2166 * here, after the parent opened its own user namespace. */
2169 errno_pipe
[0] = safe_close(errno_pipe
[0]);
2171 /* Wait until the parent unshared the user namespace */
2172 if (read(unshare_ready_fd
, &c
, sizeof(c
)) < 0) {
2177 /* Disable the setgroups() system call in the child user namespace, for good. */
2178 a
= procfs_file_alloca(ppid
, "setgroups");
2179 fd
= open(a
, O_WRONLY
|O_CLOEXEC
);
2181 if (errno
!= ENOENT
) {
2186 /* If the file is missing the kernel is too old, let's continue anyway. */
2188 if (write(fd
, "deny\n", 5) < 0) {
2193 fd
= safe_close(fd
);
2196 /* First write the GID map */
2197 a
= procfs_file_alloca(ppid
, "gid_map");
2198 fd
= open(a
, O_WRONLY
|O_CLOEXEC
);
2203 if (write(fd
, gid_map
, strlen(gid_map
)) < 0) {
2207 fd
= safe_close(fd
);
2209 /* The write the UID map */
2210 a
= procfs_file_alloca(ppid
, "uid_map");
2211 fd
= open(a
, O_WRONLY
|O_CLOEXEC
);
2216 if (write(fd
, uid_map
, strlen(uid_map
)) < 0) {
2221 _exit(EXIT_SUCCESS
);
2224 (void) write(errno_pipe
[1], &r
, sizeof(r
));
2225 _exit(EXIT_FAILURE
);
2228 errno_pipe
[1] = safe_close(errno_pipe
[1]);
2230 if (unshare(CLONE_NEWUSER
) < 0)
2233 /* Let the child know that the namespace is ready now */
2234 if (write(unshare_ready_fd
, &c
, sizeof(c
)) < 0)
2237 /* Try to read an error code from the child */
2238 n
= read(errno_pipe
[0], &r
, sizeof(r
));
2241 if (n
== sizeof(r
)) { /* an error code was sent to us */
2246 if (n
!= 0) /* on success we should have read 0 bytes */
2249 r
= wait_for_terminate_and_check("(sd-userns)", TAKE_PID(pid
), 0);
2252 if (r
!= EXIT_SUCCESS
) /* If something strange happened with the child, let's consider this fatal, too */
2258 static int create_many_symlinks(const char *root
, const char *source
, char **symlinks
) {
2259 _cleanup_free_
char *src_abs
= NULL
;
2264 src_abs
= path_join(root
, source
);
2268 STRV_FOREACH(dst
, symlinks
) {
2269 _cleanup_free_
char *dst_abs
= NULL
;
2271 dst_abs
= path_join(root
, *dst
);
2275 r
= mkdir_parents_label(dst_abs
, 0755);
2279 r
= symlink_idempotent(src_abs
, dst_abs
, true);
2287 static int setup_exec_directory(
2288 const ExecContext
*context
,
2289 const ExecParameters
*params
,
2292 ExecDirectoryType type
,
2293 bool needs_mount_namespace
,
2296 static const int exit_status_table
[_EXEC_DIRECTORY_TYPE_MAX
] = {
2297 [EXEC_DIRECTORY_RUNTIME
] = EXIT_RUNTIME_DIRECTORY
,
2298 [EXEC_DIRECTORY_STATE
] = EXIT_STATE_DIRECTORY
,
2299 [EXEC_DIRECTORY_CACHE
] = EXIT_CACHE_DIRECTORY
,
2300 [EXEC_DIRECTORY_LOGS
] = EXIT_LOGS_DIRECTORY
,
2301 [EXEC_DIRECTORY_CONFIGURATION
] = EXIT_CONFIGURATION_DIRECTORY
,
2307 assert(type
>= 0 && type
< _EXEC_DIRECTORY_TYPE_MAX
);
2308 assert(exit_status
);
2310 if (!params
->prefix
[type
])
2313 if (params
->flags
& EXEC_CHOWN_DIRECTORIES
) {
2314 if (!uid_is_valid(uid
))
2316 if (!gid_is_valid(gid
))
2320 for (size_t i
= 0; i
< context
->directories
[type
].n_items
; i
++) {
2321 _cleanup_free_
char *p
= NULL
, *pp
= NULL
;
2323 p
= path_join(params
->prefix
[type
], context
->directories
[type
].items
[i
].path
);
2329 r
= mkdir_parents_label(p
, 0755);
2333 if (IN_SET(type
, EXEC_DIRECTORY_STATE
, EXEC_DIRECTORY_LOGS
) && params
->runtime_scope
== RUNTIME_SCOPE_USER
) {
2335 /* If we are in user mode, and a configuration directory exists but a state directory
2336 * doesn't exist, then we likely are upgrading from an older systemd version that
2337 * didn't know the more recent addition to the xdg-basedir spec: the $XDG_STATE_HOME
2338 * directory. In older systemd versions EXEC_DIRECTORY_STATE was aliased to
2339 * EXEC_DIRECTORY_CONFIGURATION, with the advent of $XDG_STATE_HOME is is now
2340 * separated. If a service has both dirs configured but only the configuration dir
2341 * exists and the state dir does not, we assume we are looking at an update
2342 * situation. Hence, create a compatibility symlink, so that all expectations are
2345 * (We also do something similar with the log directory, which still doesn't exist in
2346 * the xdg basedir spec. We'll make it a subdir of the state dir.) */
2348 /* this assumes the state dir is always created before the configuration dir */
2349 assert_cc(EXEC_DIRECTORY_STATE
< EXEC_DIRECTORY_LOGS
);
2350 assert_cc(EXEC_DIRECTORY_LOGS
< EXEC_DIRECTORY_CONFIGURATION
);
2352 r
= laccess(p
, F_OK
);
2354 _cleanup_free_
char *q
= NULL
;
2356 /* OK, we know that the state dir does not exist. Let's see if the dir exists
2357 * under the configuration hierarchy. */
2359 if (type
== EXEC_DIRECTORY_STATE
)
2360 q
= path_join(params
->prefix
[EXEC_DIRECTORY_CONFIGURATION
], context
->directories
[type
].items
[i
].path
);
2361 else if (type
== EXEC_DIRECTORY_LOGS
)
2362 q
= path_join(params
->prefix
[EXEC_DIRECTORY_CONFIGURATION
], "log", context
->directories
[type
].items
[i
].path
);
2364 assert_not_reached();
2370 r
= laccess(q
, F_OK
);
2372 /* It does exist! This hence looks like an update. Symlink the
2373 * configuration directory into the state directory. */
2375 r
= symlink_idempotent(q
, p
, /* make_relative= */ true);
2379 log_exec_notice(context
, params
, "Unit state directory %s missing but matching configuration directory %s exists, assuming update from systemd 253 or older, creating compatibility symlink.", p
, q
);
2381 } else if (r
!= -ENOENT
)
2382 log_exec_warning_errno(context
, params
, r
, "Unable to detect whether unit configuration directory '%s' exists, assuming not: %m", q
);
2385 log_exec_warning_errno(context
, params
, r
, "Unable to detect whether unit state directory '%s' is missing, assuming it is: %m", p
);
2388 if (exec_directory_is_private(context
, type
)) {
2389 /* So, here's one extra complication when dealing with DynamicUser=1 units. In that
2390 * case we want to avoid leaving a directory around fully accessible that is owned by
2391 * a dynamic user whose UID is later on reused. To lock this down we use the same
2392 * trick used by container managers to prohibit host users to get access to files of
2393 * the same UID in containers: we place everything inside a directory that has an
2394 * access mode of 0700 and is owned root:root, so that it acts as security boundary
2395 * for unprivileged host code. We then use fs namespacing to make this directory
2396 * permeable for the service itself.
2398 * Specifically: for a service which wants a special directory "foo/" we first create
2399 * a directory "private/" with access mode 0700 owned by root:root. Then we place
2400 * "foo" inside of that directory (i.e. "private/foo/"), and make "foo" a symlink to
2401 * "private/foo". This way, privileged host users can access "foo/" as usual, but
2402 * unprivileged host users can't look into it. Inside of the namespace of the unit
2403 * "private/" is replaced by a more liberally accessible tmpfs, into which the host's
2404 * "private/foo/" is mounted under the same name, thus disabling the access boundary
2405 * for the service and making sure it only gets access to the dirs it needs but no
2406 * others. Tricky? Yes, absolutely, but it works!
2408 * Note that we don't do this for EXEC_DIRECTORY_CONFIGURATION as that's assumed not
2409 * to be owned by the service itself.
2411 * Also, note that we don't do this for EXEC_DIRECTORY_RUNTIME as that's often used
2412 * for sharing files or sockets with other services. */
2414 pp
= path_join(params
->prefix
[type
], "private");
2420 /* First set up private root if it doesn't exist yet, with access mode 0700 and owned by root:root */
2421 r
= mkdir_safe_label(pp
, 0700, 0, 0, MKDIR_WARN_MODE
);
2425 if (!path_extend(&pp
, context
->directories
[type
].items
[i
].path
)) {
2430 /* Create all directories between the configured directory and this private root, and mark them 0755 */
2431 r
= mkdir_parents_label(pp
, 0755);
2435 if (is_dir(p
, false) > 0 &&
2436 (laccess(pp
, F_OK
) == -ENOENT
)) {
2438 /* Hmm, the private directory doesn't exist yet, but the normal one exists? If so, move
2439 * it over. Most likely the service has been upgraded from one that didn't use
2440 * DynamicUser=1, to one that does. */
2442 log_exec_info(context
,
2444 "Found pre-existing public %s= directory %s, migrating to %s.\n"
2445 "Apparently, service previously had DynamicUser= turned off, and has now turned it on.",
2446 exec_directory_type_to_string(type
), p
, pp
);
2448 r
= RET_NERRNO(rename(p
, pp
));
2452 /* Otherwise, create the actual directory for the service */
2454 r
= mkdir_label(pp
, context
->directories
[type
].mode
);
2455 if (r
< 0 && r
!= -EEXIST
)
2459 if (!context
->directories
[type
].items
[i
].only_create
) {
2460 /* And link it up from the original place.
2462 * 1) If a mount namespace is going to be used, then this symlink remains on
2463 * the host, and a new one for the child namespace will be created later.
2464 * 2) It is not necessary to create this symlink when one of its parent
2465 * directories is specified and already created. E.g.
2466 * StateDirectory=foo foo/bar
2467 * In that case, the inode points to pp and p for "foo/bar" are the same:
2468 * pp = "/var/lib/private/foo/bar"
2469 * p = "/var/lib/foo/bar"
2470 * and, /var/lib/foo is a symlink to /var/lib/private/foo. So, not only
2471 * we do not need to create the symlink, but we cannot create the symlink.
2472 * See issue #24783. */
2473 r
= symlink_idempotent(pp
, p
, true);
2479 _cleanup_free_
char *target
= NULL
;
2481 if (type
!= EXEC_DIRECTORY_CONFIGURATION
&&
2482 readlink_and_make_absolute(p
, &target
) >= 0) {
2483 _cleanup_free_
char *q
= NULL
, *q_resolved
= NULL
, *target_resolved
= NULL
;
2485 /* This already exists and is a symlink? Interesting. Maybe it's one created
2486 * by DynamicUser=1 (see above)?
2488 * We do this for all directory types except for ConfigurationDirectory=,
2489 * since they all support the private/ symlink logic at least in some
2490 * configurations, see above. */
2492 r
= chase(target
, NULL
, 0, &target_resolved
, NULL
);
2496 q
= path_join(params
->prefix
[type
], "private", context
->directories
[type
].items
[i
].path
);
2502 /* /var/lib or friends may be symlinks. So, let's chase them also. */
2503 r
= chase(q
, NULL
, CHASE_NONEXISTENT
, &q_resolved
, NULL
);
2507 if (path_equal(q_resolved
, target_resolved
)) {
2509 /* Hmm, apparently DynamicUser= was once turned on for this service,
2510 * but is no longer. Let's move the directory back up. */
2512 log_exec_info(context
,
2514 "Found pre-existing private %s= directory %s, migrating to %s.\n"
2515 "Apparently, service previously had DynamicUser= turned on, and has now turned it off.",
2516 exec_directory_type_to_string(type
), q
, p
);
2518 r
= RET_NERRNO(unlink(p
));
2522 r
= RET_NERRNO(rename(q
, p
));
2528 r
= mkdir_label(p
, context
->directories
[type
].mode
);
2533 if (type
== EXEC_DIRECTORY_CONFIGURATION
) {
2536 /* Don't change the owner/access mode of the configuration directory,
2537 * as in the common case it is not written to by a service, and shall
2538 * not be writable. */
2540 r
= RET_NERRNO(stat(p
, &st
));
2544 /* Still complain if the access mode doesn't match */
2545 if (((st
.st_mode
^ context
->directories
[type
].mode
) & 07777) != 0)
2546 log_exec_warning(context
,
2548 "%s \'%s\' already exists but the mode is different. "
2549 "(File system: %o %sMode: %o)",
2550 exec_directory_type_to_string(type
), context
->directories
[type
].items
[i
].path
,
2551 st
.st_mode
& 07777, exec_directory_type_to_string(type
), context
->directories
[type
].mode
& 07777);
2558 /* Lock down the access mode (we use chmod_and_chown() to make this idempotent. We don't
2559 * specify UID/GID here, so that path_chown_recursive() can optimize things depending on the
2560 * current UID/GID ownership.) */
2561 r
= chmod_and_chown(pp
?: p
, context
->directories
[type
].mode
, UID_INVALID
, GID_INVALID
);
2565 /* Skip the rest (which deals with ownership) in user mode, since ownership changes are not
2566 * available to user code anyway */
2567 if (params
->runtime_scope
!= RUNTIME_SCOPE_SYSTEM
)
2570 /* Then, change the ownership of the whole tree, if necessary. When dynamic users are used we
2571 * drop the suid/sgid bits, since we really don't want SUID/SGID files for dynamic UID/GID
2572 * assignments to exist. */
2573 r
= path_chown_recursive(pp
?: p
, uid
, gid
, context
->dynamic_user
? 01777 : 07777, AT_SYMLINK_FOLLOW
);
2578 /* If we are not going to run in a namespace, set up the symlinks - otherwise
2579 * they are set up later, to allow configuring empty var/run/etc. */
2580 if (!needs_mount_namespace
)
2581 for (size_t i
= 0; i
< context
->directories
[type
].n_items
; i
++) {
2582 r
= create_many_symlinks(params
->prefix
[type
],
2583 context
->directories
[type
].items
[i
].path
,
2584 context
->directories
[type
].items
[i
].symlinks
);
2592 *exit_status
= exit_status_table
[type
];
2597 static int setup_smack(
2598 const ExecParameters
*params
,
2599 const ExecContext
*context
,
2600 int executable_fd
) {
2604 assert(executable_fd
>= 0);
2606 if (context
->smack_process_label
) {
2607 r
= mac_smack_apply_pid(0, context
->smack_process_label
);
2610 } else if (params
->fallback_smack_process_label
) {
2611 _cleanup_free_
char *exec_label
= NULL
;
2613 r
= mac_smack_read_fd(executable_fd
, SMACK_ATTR_EXEC
, &exec_label
);
2614 if (r
< 0 && !ERRNO_IS_XATTR_ABSENT(r
))
2617 r
= mac_smack_apply_pid(0, exec_label
?: params
->fallback_smack_process_label
);
2626 static int compile_bind_mounts(
2627 const ExecContext
*context
,
2628 const ExecParameters
*params
,
2629 BindMount
**ret_bind_mounts
,
2630 size_t *ret_n_bind_mounts
,
2631 char ***ret_empty_directories
) {
2633 _cleanup_strv_free_
char **empty_directories
= NULL
;
2634 BindMount
*bind_mounts
= NULL
;
2640 assert(ret_bind_mounts
);
2641 assert(ret_n_bind_mounts
);
2642 assert(ret_empty_directories
);
2644 CLEANUP_ARRAY(bind_mounts
, h
, bind_mount_free_many
);
2646 n
= context
->n_bind_mounts
;
2647 for (ExecDirectoryType t
= 0; t
< _EXEC_DIRECTORY_TYPE_MAX
; t
++) {
2648 if (!params
->prefix
[t
])
2651 for (size_t i
= 0; i
< context
->directories
[t
].n_items
; i
++)
2652 n
+= !context
->directories
[t
].items
[i
].only_create
;
2656 *ret_bind_mounts
= NULL
;
2657 *ret_n_bind_mounts
= 0;
2658 *ret_empty_directories
= NULL
;
2662 bind_mounts
= new(BindMount
, n
);
2666 for (size_t i
= 0; i
< context
->n_bind_mounts
; i
++) {
2667 BindMount
*item
= context
->bind_mounts
+ i
;
2668 _cleanup_free_
char *s
= NULL
, *d
= NULL
;
2670 s
= strdup(item
->source
);
2674 d
= strdup(item
->destination
);
2678 bind_mounts
[h
++] = (BindMount
) {
2679 .source
= TAKE_PTR(s
),
2680 .destination
= TAKE_PTR(d
),
2681 .read_only
= item
->read_only
,
2682 .recursive
= item
->recursive
,
2683 .ignore_enoent
= item
->ignore_enoent
,
2687 for (ExecDirectoryType t
= 0; t
< _EXEC_DIRECTORY_TYPE_MAX
; t
++) {
2688 if (!params
->prefix
[t
])
2691 if (context
->directories
[t
].n_items
== 0)
2694 if (exec_directory_is_private(context
, t
) &&
2695 !exec_context_with_rootfs(context
)) {
2698 /* So this is for a dynamic user, and we need to make sure the process can access its own
2699 * directory. For that we overmount the usually inaccessible "private" subdirectory with a
2700 * tmpfs that makes it accessible and is empty except for the submounts we do this for. */
2702 private_root
= path_join(params
->prefix
[t
], "private");
2706 r
= strv_consume(&empty_directories
, private_root
);
2711 for (size_t i
= 0; i
< context
->directories
[t
].n_items
; i
++) {
2712 _cleanup_free_
char *s
= NULL
, *d
= NULL
;
2714 /* When one of the parent directories is in the list, we cannot create the symlink
2715 * for the child directory. See also the comments in setup_exec_directory(). */
2716 if (context
->directories
[t
].items
[i
].only_create
)
2719 if (exec_directory_is_private(context
, t
))
2720 s
= path_join(params
->prefix
[t
], "private", context
->directories
[t
].items
[i
].path
);
2722 s
= path_join(params
->prefix
[t
], context
->directories
[t
].items
[i
].path
);
2726 if (exec_directory_is_private(context
, t
) &&
2727 exec_context_with_rootfs(context
))
2728 /* When RootDirectory= or RootImage= are set, then the symbolic link to the private
2729 * directory is not created on the root directory. So, let's bind-mount the directory
2730 * on the 'non-private' place. */
2731 d
= path_join(params
->prefix
[t
], context
->directories
[t
].items
[i
].path
);
2737 bind_mounts
[h
++] = (BindMount
) {
2738 .source
= TAKE_PTR(s
),
2739 .destination
= TAKE_PTR(d
),
2741 .nosuid
= context
->dynamic_user
, /* don't allow suid/sgid when DynamicUser= is on */
2743 .ignore_enoent
= false,
2750 *ret_bind_mounts
= TAKE_PTR(bind_mounts
);
2751 *ret_n_bind_mounts
= n
;
2752 *ret_empty_directories
= TAKE_PTR(empty_directories
);
2757 /* ret_symlinks will contain a list of pairs src:dest that describes
2758 * the symlinks to create later on. For example, the symlinks needed
2759 * to safely give private directories to DynamicUser=1 users. */
2760 static int compile_symlinks(
2761 const ExecContext
*context
,
2762 const ExecParameters
*params
,
2763 bool setup_os_release_symlink
,
2764 char ***ret_symlinks
) {
2766 _cleanup_strv_free_
char **symlinks
= NULL
;
2771 assert(ret_symlinks
);
2773 for (ExecDirectoryType dt
= 0; dt
< _EXEC_DIRECTORY_TYPE_MAX
; dt
++) {
2774 for (size_t i
= 0; i
< context
->directories
[dt
].n_items
; i
++) {
2775 _cleanup_free_
char *private_path
= NULL
, *path
= NULL
;
2777 STRV_FOREACH(symlink
, context
->directories
[dt
].items
[i
].symlinks
) {
2778 _cleanup_free_
char *src_abs
= NULL
, *dst_abs
= NULL
;
2780 src_abs
= path_join(params
->prefix
[dt
], context
->directories
[dt
].items
[i
].path
);
2781 dst_abs
= path_join(params
->prefix
[dt
], *symlink
);
2782 if (!src_abs
|| !dst_abs
)
2785 r
= strv_consume_pair(&symlinks
, TAKE_PTR(src_abs
), TAKE_PTR(dst_abs
));
2790 if (!exec_directory_is_private(context
, dt
) ||
2791 exec_context_with_rootfs(context
) ||
2792 context
->directories
[dt
].items
[i
].only_create
)
2795 private_path
= path_join(params
->prefix
[dt
], "private", context
->directories
[dt
].items
[i
].path
);
2799 path
= path_join(params
->prefix
[dt
], context
->directories
[dt
].items
[i
].path
);
2803 r
= strv_consume_pair(&symlinks
, TAKE_PTR(private_path
), TAKE_PTR(path
));
2809 /* We make the host's os-release available via a symlink, so that we can copy it atomically
2810 * and readers will never get a half-written version. Note that, while the paths specified here are
2811 * absolute, when they are processed in namespace.c they will be made relative automatically, i.e.:
2812 * 'os-release -> .os-release-stage/os-release' is what will be created. */
2813 if (setup_os_release_symlink
) {
2814 r
= strv_extend_many(
2816 "/run/host/.os-release-stage/os-release",
2817 "/run/host/os-release");
2822 *ret_symlinks
= TAKE_PTR(symlinks
);
2827 static bool insist_on_sandboxing(
2828 const ExecContext
*context
,
2829 const char *root_dir
,
2830 const char *root_image
,
2831 const BindMount
*bind_mounts
,
2832 size_t n_bind_mounts
) {
2835 assert(n_bind_mounts
== 0 || bind_mounts
);
2837 /* Checks whether we need to insist on fs namespacing. i.e. whether we have settings configured that
2838 * would alter the view on the file system beyond making things read-only or invisible, i.e. would
2839 * rearrange stuff in a way we cannot ignore gracefully. */
2841 if (context
->n_temporary_filesystems
> 0)
2844 if (root_dir
|| root_image
)
2847 if (context
->n_mount_images
> 0)
2850 if (context
->dynamic_user
)
2853 if (context
->n_extension_images
> 0 || !strv_isempty(context
->extension_directories
))
2856 /* If there are any bind mounts set that don't map back onto themselves, fs namespacing becomes
2858 for (size_t i
= 0; i
< n_bind_mounts
; i
++)
2859 if (!path_equal(bind_mounts
[i
].source
, bind_mounts
[i
].destination
))
2862 if (context
->log_namespace
)
2868 static int setup_ephemeral(
2869 const ExecContext
*context
,
2870 ExecRuntime
*runtime
,
2871 char **root_image
, /* both input and output! modified if ephemeral logic enabled */
2872 char **root_directory
) { /* ditto */
2874 _cleanup_close_
int fd
= -EBADF
;
2875 _cleanup_free_
char *new_root
= NULL
;
2880 assert(root_directory
);
2882 if (!*root_image
&& !*root_directory
)
2885 if (!runtime
|| !runtime
->ephemeral_copy
)
2888 assert(runtime
->ephemeral_storage_socket
[0] >= 0);
2889 assert(runtime
->ephemeral_storage_socket
[1] >= 0);
2891 new_root
= strdup(runtime
->ephemeral_copy
);
2893 return log_oom_debug();
2895 r
= posix_lock(runtime
->ephemeral_storage_socket
[0], LOCK_EX
);
2897 return log_debug_errno(r
, "Failed to lock ephemeral storage socket: %m");
2899 CLEANUP_POSIX_UNLOCK(runtime
->ephemeral_storage_socket
[0]);
2901 fd
= receive_one_fd(runtime
->ephemeral_storage_socket
[0], MSG_PEEK
|MSG_DONTWAIT
);
2903 /* We got an fd! That means ephemeral has already been set up, so nothing to do here. */
2906 return log_debug_errno(fd
, "Failed to receive file descriptor queued on ephemeral storage socket: %m");
2909 log_debug("Making ephemeral copy of %s to %s", *root_image
, new_root
);
2911 fd
= copy_file(*root_image
,
2919 return log_debug_errno(fd
, "Failed to copy image %s to %s: %m",
2920 *root_image
, new_root
);
2922 /* A root image might be subject to lots of random writes so let's try to disable COW on it
2923 * which tends to not perform well in combination with lots of random writes.
2925 * Note: btrfs actually isn't impressed by us setting the flag after making the reflink'ed
2926 * copy, but we at least want to make the intention clear.
2928 r
= chattr_fd(fd
, FS_NOCOW_FL
, FS_NOCOW_FL
, NULL
);
2930 log_debug_errno(fd
, "Failed to disable copy-on-write for %s, ignoring: %m", new_root
);
2932 assert(*root_directory
);
2934 log_debug("Making ephemeral snapshot of %s to %s", *root_directory
, new_root
);
2936 fd
= btrfs_subvol_snapshot_at(
2937 AT_FDCWD
, *root_directory
,
2939 BTRFS_SNAPSHOT_FALLBACK_COPY
|
2940 BTRFS_SNAPSHOT_FALLBACK_DIRECTORY
|
2941 BTRFS_SNAPSHOT_RECURSIVE
|
2942 BTRFS_SNAPSHOT_LOCK_BSD
);
2944 return log_debug_errno(fd
, "Failed to snapshot directory %s to %s: %m",
2945 *root_directory
, new_root
);
2948 r
= send_one_fd(runtime
->ephemeral_storage_socket
[1], fd
, MSG_DONTWAIT
);
2950 return log_debug_errno(r
, "Failed to queue file descriptor on ephemeral storage socket: %m");
2953 free_and_replace(*root_image
, new_root
);
2955 assert(*root_directory
);
2956 free_and_replace(*root_directory
, new_root
);
2962 static int verity_settings_prepare(
2963 VeritySettings
*verity
,
2964 const char *root_image
,
2965 const void *root_hash
,
2966 size_t root_hash_size
,
2967 const char *root_hash_path
,
2968 const void *root_hash_sig
,
2969 size_t root_hash_sig_size
,
2970 const char *root_hash_sig_path
,
2971 const char *verity_data_path
) {
2980 d
= memdup(root_hash
, root_hash_size
);
2984 free_and_replace(verity
->root_hash
, d
);
2985 verity
->root_hash_size
= root_hash_size
;
2986 verity
->designator
= PARTITION_ROOT
;
2989 if (root_hash_sig
) {
2992 d
= memdup(root_hash_sig
, root_hash_sig_size
);
2996 free_and_replace(verity
->root_hash_sig
, d
);
2997 verity
->root_hash_sig_size
= root_hash_sig_size
;
2998 verity
->designator
= PARTITION_ROOT
;
3001 if (verity_data_path
) {
3002 r
= free_and_strdup(&verity
->data_path
, verity_data_path
);
3007 r
= verity_settings_load(
3011 root_hash_sig_path
);
3013 return log_debug_errno(r
, "Failed to load root hash: %m");
3018 static int pick_versions(
3019 const ExecContext
*context
,
3020 const ExecParameters
*params
,
3021 char **ret_root_image
,
3022 char **ret_root_directory
) {
3028 assert(ret_root_image
);
3029 assert(ret_root_directory
);
3031 if (context
->root_image
) {
3032 _cleanup_(pick_result_done
) PickResult result
= PICK_RESULT_NULL
;
3034 r
= path_pick(/* toplevel_path= */ NULL
,
3035 /* toplevel_fd= */ AT_FDCWD
,
3036 context
->root_image
,
3037 &pick_filter_image_raw
,
3038 PICK_ARCHITECTURE
|PICK_TRIES
|PICK_RESOLVE
,
3044 return log_exec_debug_errno(context
, params
, SYNTHETIC_ERRNO(ENOENT
), "No matching entry in .v/ directory %s found.", context
->root_image
);
3046 *ret_root_image
= TAKE_PTR(result
.path
);
3047 *ret_root_directory
= NULL
;
3051 if (context
->root_directory
) {
3052 _cleanup_(pick_result_done
) PickResult result
= PICK_RESULT_NULL
;
3054 r
= path_pick(/* toplevel_path= */ NULL
,
3055 /* toplevel_fd= */ AT_FDCWD
,
3056 context
->root_directory
,
3057 &pick_filter_image_dir
,
3058 PICK_ARCHITECTURE
|PICK_TRIES
|PICK_RESOLVE
,
3064 return log_exec_debug_errno(context
, params
, SYNTHETIC_ERRNO(ENOENT
), "No matching entry in .v/ directory %s found.", context
->root_directory
);
3066 *ret_root_image
= NULL
;
3067 *ret_root_directory
= TAKE_PTR(result
.path
);
3071 *ret_root_image
= *ret_root_directory
= NULL
;
3075 static int apply_mount_namespace(
3076 ExecCommandFlags command_flags
,
3077 const ExecContext
*context
,
3078 const ExecParameters
*params
,
3079 ExecRuntime
*runtime
,
3080 const char *memory_pressure_path
,
3081 char **error_path
) {
3083 _cleanup_(verity_settings_done
) VeritySettings verity
= VERITY_SETTINGS_DEFAULT
;
3084 _cleanup_strv_free_
char **empty_directories
= NULL
, **symlinks
= NULL
,
3085 **read_write_paths_cleanup
= NULL
;
3086 _cleanup_free_
char *creds_path
= NULL
, *incoming_dir
= NULL
, *propagate_dir
= NULL
,
3087 *extension_dir
= NULL
, *host_os_release_stage
= NULL
, *root_image
= NULL
, *root_dir
= NULL
;
3088 const char *tmp_dir
= NULL
, *var_tmp_dir
= NULL
;
3089 char **read_write_paths
;
3090 bool needs_sandboxing
, setup_os_release_symlink
;
3091 BindMount
*bind_mounts
= NULL
;
3092 size_t n_bind_mounts
= 0;
3097 CLEANUP_ARRAY(bind_mounts
, n_bind_mounts
, bind_mount_free_many
);
3099 if (params
->flags
& EXEC_APPLY_CHROOT
) {
3108 r
= setup_ephemeral(
3117 r
= compile_bind_mounts(context
, params
, &bind_mounts
, &n_bind_mounts
, &empty_directories
);
3121 /* We need to make the pressure path writable even if /sys/fs/cgroups is made read-only, as the
3122 * service will need to write to it in order to start the notifications. */
3123 if (context
->protect_control_groups
&& memory_pressure_path
&& !streq(memory_pressure_path
, "/dev/null")) {
3124 read_write_paths_cleanup
= strv_copy(context
->read_write_paths
);
3125 if (!read_write_paths_cleanup
)
3128 r
= strv_extend(&read_write_paths_cleanup
, memory_pressure_path
);
3132 read_write_paths
= read_write_paths_cleanup
;
3134 read_write_paths
= context
->read_write_paths
;
3136 needs_sandboxing
= (params
->flags
& EXEC_APPLY_SANDBOXING
) && !(command_flags
& EXEC_COMMAND_FULLY_PRIVILEGED
);
3137 if (needs_sandboxing
) {
3138 /* The runtime struct only contains the parent of the private /tmp, which is non-accessible
3139 * to world users. Inside of it there's a /tmp that is sticky, and that's the one we want to
3140 * use here. This does not apply when we are using /run/systemd/empty as fallback. */
3142 if (context
->private_tmp
&& runtime
&& runtime
->shared
) {
3143 if (streq_ptr(runtime
->shared
->tmp_dir
, RUN_SYSTEMD_EMPTY
))
3144 tmp_dir
= runtime
->shared
->tmp_dir
;
3145 else if (runtime
->shared
->tmp_dir
)
3146 tmp_dir
= strjoina(runtime
->shared
->tmp_dir
, "/tmp");
3148 if (streq_ptr(runtime
->shared
->var_tmp_dir
, RUN_SYSTEMD_EMPTY
))
3149 var_tmp_dir
= runtime
->shared
->var_tmp_dir
;
3150 else if (runtime
->shared
->var_tmp_dir
)
3151 var_tmp_dir
= strjoina(runtime
->shared
->var_tmp_dir
, "/tmp");
3155 /* Symlinks (exec dirs, os-release) are set up after other mounts, before they are made read-only. */
3156 setup_os_release_symlink
= needs_sandboxing
&& exec_context_get_effective_mount_apivfs(context
) && (root_dir
|| root_image
);
3157 r
= compile_symlinks(context
, params
, setup_os_release_symlink
, &symlinks
);
3161 if (context
->mount_propagation_flag
== MS_SHARED
)
3162 log_exec_debug(context
,
3164 "shared mount propagation hidden by other fs namespacing unit settings: ignoring");
3166 if (FLAGS_SET(params
->flags
, EXEC_WRITE_CREDENTIALS
)) {
3167 r
= exec_context_get_credential_directory(context
, params
, params
->unit_id
, &creds_path
);
3172 if (params
->runtime_scope
== RUNTIME_SCOPE_SYSTEM
) {
3173 propagate_dir
= path_join("/run/systemd/propagate/", params
->unit_id
);
3177 incoming_dir
= strdup("/run/systemd/incoming");
3181 extension_dir
= strdup("/run/systemd/unit-extensions");
3185 /* If running under a different root filesystem, propagate the host's os-release. We make a
3186 * copy rather than just bind mounting it, so that it can be updated on soft-reboot. */
3187 if (setup_os_release_symlink
) {
3188 host_os_release_stage
= strdup("/run/systemd/propagate/.os-release-stage");
3189 if (!host_os_release_stage
)
3193 assert(params
->runtime_scope
== RUNTIME_SCOPE_USER
);
3195 if (asprintf(&extension_dir
, "/run/user/" UID_FMT
"/systemd/unit-extensions", geteuid()) < 0)
3198 if (setup_os_release_symlink
) {
3199 if (asprintf(&host_os_release_stage
,
3200 "/run/user/" UID_FMT
"/systemd/propagate/.os-release-stage",
3207 r
= verity_settings_prepare(
3210 context
->root_hash
, context
->root_hash_size
, context
->root_hash_path
,
3211 context
->root_hash_sig
, context
->root_hash_sig_size
, context
->root_hash_sig_path
,
3212 context
->root_verity
);
3217 NamespaceParameters parameters
= {
3218 .runtime_scope
= params
->runtime_scope
,
3220 .root_directory
= root_dir
,
3221 .root_image
= root_image
,
3222 .root_image_options
= context
->root_image_options
,
3223 .root_image_policy
= context
->root_image_policy
?: &image_policy_service
,
3225 .read_write_paths
= read_write_paths
,
3226 .read_only_paths
= needs_sandboxing
? context
->read_only_paths
: NULL
,
3227 .inaccessible_paths
= needs_sandboxing
? context
->inaccessible_paths
: NULL
,
3229 .exec_paths
= needs_sandboxing
? context
->exec_paths
: NULL
,
3230 .no_exec_paths
= needs_sandboxing
? context
->no_exec_paths
: NULL
,
3232 .empty_directories
= empty_directories
,
3233 .symlinks
= symlinks
,
3235 .bind_mounts
= bind_mounts
,
3236 .n_bind_mounts
= n_bind_mounts
,
3238 .temporary_filesystems
= context
->temporary_filesystems
,
3239 .n_temporary_filesystems
= context
->n_temporary_filesystems
,
3241 .mount_images
= context
->mount_images
,
3242 .n_mount_images
= context
->n_mount_images
,
3243 .mount_image_policy
= context
->mount_image_policy
?: &image_policy_service
,
3246 .var_tmp_dir
= var_tmp_dir
,
3248 .creds_path
= creds_path
,
3249 .log_namespace
= context
->log_namespace
,
3250 .mount_propagation_flag
= context
->mount_propagation_flag
,
3254 .extension_images
= context
->extension_images
,
3255 .n_extension_images
= context
->n_extension_images
,
3256 .extension_image_policy
= context
->extension_image_policy
?: &image_policy_sysext
,
3257 .extension_directories
= context
->extension_directories
,
3259 .propagate_dir
= propagate_dir
,
3260 .incoming_dir
= incoming_dir
,
3261 .extension_dir
= extension_dir
,
3262 .notify_socket
= root_dir
|| root_image
? params
->notify_socket
: NULL
,
3263 .host_os_release_stage
= host_os_release_stage
,
3265 /* If DynamicUser=no and RootDirectory= is set then lets pass a relaxed sandbox info,
3266 * otherwise enforce it, don't ignore protected paths and fail if we are enable to apply the
3267 * sandbox inside the mount namespace. */
3268 .ignore_protect_paths
= !needs_sandboxing
&& !context
->dynamic_user
&& root_dir
,
3270 .protect_control_groups
= needs_sandboxing
&& context
->protect_control_groups
,
3271 .protect_kernel_tunables
= needs_sandboxing
&& context
->protect_kernel_tunables
,
3272 .protect_kernel_modules
= needs_sandboxing
&& context
->protect_kernel_modules
,
3273 .protect_kernel_logs
= needs_sandboxing
&& context
->protect_kernel_logs
,
3274 .protect_hostname
= needs_sandboxing
&& context
->protect_hostname
,
3276 .private_dev
= needs_sandboxing
&& context
->private_devices
,
3277 .private_network
= needs_sandboxing
&& exec_needs_network_namespace(context
),
3278 .private_ipc
= needs_sandboxing
&& exec_needs_ipc_namespace(context
),
3280 .mount_apivfs
= needs_sandboxing
&& exec_context_get_effective_mount_apivfs(context
),
3282 /* If NNP is on, we can turn on MS_NOSUID, since it won't have any effect anymore. */
3283 .mount_nosuid
= needs_sandboxing
&& context
->no_new_privileges
&& !mac_selinux_use(),
3285 .protect_home
= needs_sandboxing
? context
->protect_home
: false,
3286 .protect_system
= needs_sandboxing
? context
->protect_system
: false,
3287 .protect_proc
= needs_sandboxing
? context
->protect_proc
: false,
3288 .proc_subset
= needs_sandboxing
? context
->proc_subset
: false,
3291 r
= setup_namespace(¶meters
, error_path
);
3292 /* If we couldn't set up the namespace this is probably due to a missing capability. setup_namespace() reports
3293 * that with a special, recognizable error ENOANO. In this case, silently proceed, but only if exclusively
3294 * sandboxing options were used, i.e. nothing such as RootDirectory= or BindMount= that would result in a
3295 * completely different execution environment. */
3297 if (insist_on_sandboxing(
3299 root_dir
, root_image
,
3302 return log_exec_debug_errno(context
,
3304 SYNTHETIC_ERRNO(EOPNOTSUPP
),
3305 "Failed to set up namespace, and refusing to continue since "
3306 "the selected namespacing options alter mount environment non-trivially.\n"
3307 "Bind mounts: %zu, temporary filesystems: %zu, root directory: %s, root image: %s, dynamic user: %s",
3309 context
->n_temporary_filesystems
,
3312 yes_no(context
->dynamic_user
));
3314 log_exec_debug(context
, params
, "Failed to set up namespace, assuming containerized execution and ignoring.");
3321 static int apply_working_directory(
3322 const ExecContext
*context
,
3323 const ExecParameters
*params
,
3324 ExecRuntime
*runtime
,
3331 assert(exit_status
);
3333 if (context
->working_directory_home
) {
3336 *exit_status
= EXIT_CHDIR
;
3343 wd
= empty_to_root(context
->working_directory
);
3345 if (params
->flags
& EXEC_APPLY_CHROOT
)
3348 d
= prefix_roota((runtime
? runtime
->ephemeral_copy
: NULL
) ?: context
->root_directory
, wd
);
3350 if (chdir(d
) < 0 && !context
->working_directory_missing_ok
) {
3351 *exit_status
= EXIT_CHDIR
;
3358 static int apply_root_directory(
3359 const ExecContext
*context
,
3360 const ExecParameters
*params
,
3361 ExecRuntime
*runtime
,
3362 const bool needs_mount_ns
,
3366 assert(exit_status
);
3368 if (params
->flags
& EXEC_APPLY_CHROOT
)
3369 if (!needs_mount_ns
&& context
->root_directory
)
3370 if (chroot((runtime
? runtime
->ephemeral_copy
: NULL
) ?: context
->root_directory
) < 0) {
3371 *exit_status
= EXIT_CHROOT
;
3378 static int setup_keyring(
3379 const ExecContext
*context
,
3380 const ExecParameters
*p
,
3381 uid_t uid
, gid_t gid
) {
3383 key_serial_t keyring
;
3391 /* Let's set up a new per-service "session" kernel keyring for each system service. This has the benefit that
3392 * each service runs with its own keyring shared among all processes of the service, but with no hook-up beyond
3393 * that scope, and in particular no link to the per-UID keyring. If we don't do this the keyring will be
3394 * automatically created on-demand and then linked to the per-UID keyring, by the kernel. The kernel's built-in
3395 * on-demand behaviour is very appropriate for login users, but probably not so much for system services, where
3396 * UIDs are not necessarily specific to a service but reused (at least in the case of UID 0). */
3398 if (context
->keyring_mode
== EXEC_KEYRING_INHERIT
)
3401 /* Acquiring a reference to the user keyring is nasty. We briefly change identity in order to get things set up
3402 * properly by the kernel. If we don't do that then we can't create it atomically, and that sucks for parallel
3403 * execution. This mimics what pam_keyinit does, too. Setting up session keyring, to be owned by the right user
3404 * & group is just as nasty as acquiring a reference to the user keyring. */
3406 saved_uid
= getuid();
3407 saved_gid
= getgid();
3409 if (gid_is_valid(gid
) && gid
!= saved_gid
) {
3410 if (setregid(gid
, -1) < 0)
3411 return log_exec_error_errno(context
,
3414 "Failed to change GID for user keyring: %m");
3417 if (uid_is_valid(uid
) && uid
!= saved_uid
) {
3418 if (setreuid(uid
, -1) < 0) {
3419 r
= log_exec_error_errno(context
,
3422 "Failed to change UID for user keyring: %m");
3427 keyring
= keyctl(KEYCTL_JOIN_SESSION_KEYRING
, 0, 0, 0, 0);
3428 if (keyring
== -1) {
3429 if (errno
== ENOSYS
)
3430 log_exec_debug_errno(context
,
3433 "Kernel keyring not supported, ignoring.");
3434 else if (ERRNO_IS_PRIVILEGE(errno
))
3435 log_exec_debug_errno(context
,
3438 "Kernel keyring access prohibited, ignoring.");
3439 else if (errno
== EDQUOT
)
3440 log_exec_debug_errno(context
,
3443 "Out of kernel keyrings to allocate, ignoring.");
3445 r
= log_exec_error_errno(context
,
3448 "Setting up kernel keyring failed: %m");
3453 /* When requested link the user keyring into the session keyring. */
3454 if (context
->keyring_mode
== EXEC_KEYRING_SHARED
) {
3456 if (keyctl(KEYCTL_LINK
,
3457 KEY_SPEC_USER_KEYRING
,
3458 KEY_SPEC_SESSION_KEYRING
, 0, 0) < 0) {
3459 r
= log_exec_error_errno(context
,
3462 "Failed to link user keyring into session keyring: %m");
3467 /* Restore uid/gid back */
3468 if (uid_is_valid(uid
) && uid
!= saved_uid
) {
3469 if (setreuid(saved_uid
, -1) < 0) {
3470 r
= log_exec_error_errno(context
,
3473 "Failed to change UID back for user keyring: %m");
3478 if (gid_is_valid(gid
) && gid
!= saved_gid
) {
3479 if (setregid(saved_gid
, -1) < 0)
3480 return log_exec_error_errno(context
,
3483 "Failed to change GID back for user keyring: %m");
3486 /* Populate they keyring with the invocation ID by default, as original saved_uid. */
3487 if (!sd_id128_is_null(p
->invocation_id
)) {
3490 key
= add_key("user",
3493 sizeof(p
->invocation_id
),
3494 KEY_SPEC_SESSION_KEYRING
);
3496 log_exec_debug_errno(context
,
3499 "Failed to add invocation ID to keyring, ignoring: %m");
3501 if (keyctl(KEYCTL_SETPERM
, key
,
3502 KEY_POS_VIEW
|KEY_POS_READ
|KEY_POS_SEARCH
|
3503 KEY_USR_VIEW
|KEY_USR_READ
|KEY_USR_SEARCH
, 0, 0) < 0)
3504 r
= log_exec_error_errno(context
,
3507 "Failed to restrict invocation ID permission: %m");
3512 /* Revert back uid & gid for the last time, and exit */
3513 /* no extra logging, as only the first already reported error matters */
3514 if (getuid() != saved_uid
)
3515 (void) setreuid(saved_uid
, -1);
3517 if (getgid() != saved_gid
)
3518 (void) setregid(saved_gid
, -1);
3523 static void append_socket_pair(int *array
, size_t *n
, const int pair
[static 2]) {
3529 array
[(*n
)++] = pair
[0];
3531 array
[(*n
)++] = pair
[1];
3534 static int close_remaining_fds(
3535 const ExecParameters
*params
,
3536 const ExecRuntime
*runtime
,
3538 const int *fds
, size_t n_fds
) {
3540 size_t n_dont_close
= 0;
3541 int dont_close
[n_fds
+ 14];
3545 if (params
->stdin_fd
>= 0)
3546 dont_close
[n_dont_close
++] = params
->stdin_fd
;
3547 if (params
->stdout_fd
>= 0)
3548 dont_close
[n_dont_close
++] = params
->stdout_fd
;
3549 if (params
->stderr_fd
>= 0)
3550 dont_close
[n_dont_close
++] = params
->stderr_fd
;
3553 dont_close
[n_dont_close
++] = socket_fd
;
3555 memcpy(dont_close
+ n_dont_close
, fds
, sizeof(int) * n_fds
);
3556 n_dont_close
+= n_fds
;
3560 append_socket_pair(dont_close
, &n_dont_close
, runtime
->ephemeral_storage_socket
);
3562 if (runtime
&& runtime
->shared
) {
3563 append_socket_pair(dont_close
, &n_dont_close
, runtime
->shared
->netns_storage_socket
);
3564 append_socket_pair(dont_close
, &n_dont_close
, runtime
->shared
->ipcns_storage_socket
);
3567 if (runtime
&& runtime
->dynamic_creds
) {
3568 if (runtime
->dynamic_creds
->user
)
3569 append_socket_pair(dont_close
, &n_dont_close
, runtime
->dynamic_creds
->user
->storage_socket
);
3570 if (runtime
->dynamic_creds
->group
)
3571 append_socket_pair(dont_close
, &n_dont_close
, runtime
->dynamic_creds
->group
->storage_socket
);
3574 if (params
->user_lookup_fd
>= 0)
3575 dont_close
[n_dont_close
++] = params
->user_lookup_fd
;
3577 return close_all_fds(dont_close
, n_dont_close
);
3580 static int send_user_lookup(
3581 const char *unit_id
,
3588 /* Send the resolved UID/GID to PID 1 after we learnt it. We send a single datagram, containing the UID/GID
3589 * data as well as the unit name. Note that we suppress sending this if no user/group to resolve was
3592 if (user_lookup_fd
< 0)
3595 if (!uid_is_valid(uid
) && !gid_is_valid(gid
))
3598 if (writev(user_lookup_fd
,
3600 IOVEC_MAKE(&uid
, sizeof(uid
)),
3601 IOVEC_MAKE(&gid
, sizeof(gid
)),
3602 IOVEC_MAKE_STRING(unit_id
) }, 3) < 0)
3608 static int acquire_home(const ExecContext
*c
, uid_t uid
, const char** home
, char **buf
) {
3615 /* If WorkingDirectory=~ is set, try to acquire a usable home directory. */
3620 if (!c
->working_directory_home
)
3623 r
= get_home_dir(buf
);
3631 static int compile_suggested_paths(const ExecContext
*c
, const ExecParameters
*p
, char ***ret
) {
3632 _cleanup_strv_free_
char ** list
= NULL
;
3639 assert(c
->dynamic_user
);
3641 /* Compile a list of paths that it might make sense to read the owning UID from to use as initial candidate for
3642 * dynamic UID allocation, in order to save us from doing costly recursive chown()s of the special
3645 for (ExecDirectoryType t
= 0; t
< _EXEC_DIRECTORY_TYPE_MAX
; t
++) {
3646 if (t
== EXEC_DIRECTORY_CONFIGURATION
)
3652 for (size_t i
= 0; i
< c
->directories
[t
].n_items
; i
++) {
3655 if (exec_directory_is_private(c
, t
))
3656 e
= path_join(p
->prefix
[t
], "private", c
->directories
[t
].items
[i
].path
);
3658 e
= path_join(p
->prefix
[t
], c
->directories
[t
].items
[i
].path
);
3662 r
= strv_consume(&list
, e
);
3668 *ret
= TAKE_PTR(list
);
3673 static int exec_context_cpu_affinity_from_numa(const ExecContext
*c
, CPUSet
*ret
) {
3674 _cleanup_(cpu_set_reset
) CPUSet s
= {};
3680 if (!c
->numa_policy
.nodes
.set
) {
3681 log_debug("Can't derive CPU affinity mask from NUMA mask because NUMA mask is not set, ignoring");
3685 r
= numa_to_cpu_set(&c
->numa_policy
, &s
);
3691 return cpu_set_add_all(ret
, &s
);
3694 static int add_shifted_fd(int *fds
, size_t fds_size
, size_t *n_fds
, int *fd
) {
3699 assert(*n_fds
< fds_size
);
3705 if (*fd
< 3 + (int) *n_fds
) {
3706 /* Let's move the fd up, so that it's outside of the fd range we will use to store
3707 * the fds we pass to the process (or which are closed only during execve). */
3709 r
= fcntl(*fd
, F_DUPFD_CLOEXEC
, 3 + (int) *n_fds
);
3713 close_and_replace(*fd
, r
);
3716 fds
[(*n_fds
)++] = *fd
;
3720 static int connect_unix_harder(const ExecContext
*c
, const ExecParameters
*p
, const OpenFile
*of
, int ofd
) {
3721 union sockaddr_union addr
= {
3722 .un
.sun_family
= AF_UNIX
,
3725 static const int socket_types
[] = { SOCK_DGRAM
, SOCK_STREAM
, SOCK_SEQPACKET
};
3733 r
= sockaddr_un_set_path(&addr
.un
, FORMAT_PROC_FD_PATH(ofd
));
3735 return log_exec_error_errno(c
, p
, r
, "Failed to set sockaddr for %s: %m", of
->path
);
3739 for (size_t i
= 0; i
< ELEMENTSOF(socket_types
); i
++) {
3740 _cleanup_close_
int fd
= -EBADF
;
3742 fd
= socket(AF_UNIX
, socket_types
[i
] | SOCK_CLOEXEC
, 0);
3744 return log_exec_error_errno(c
,
3747 "Failed to create socket for %s: %m",
3750 r
= RET_NERRNO(connect(fd
, &addr
.sa
, sa_len
));
3751 if (r
== -EPROTOTYPE
)
3754 return log_exec_error_errno(c
,
3757 "Failed to connect socket for %s: %m",
3763 return log_exec_error_errno(c
,
3765 SYNTHETIC_ERRNO(EPROTOTYPE
), "Failed to connect socket for \"%s\".",
3769 static int get_open_file_fd(const ExecContext
*c
, const ExecParameters
*p
, const OpenFile
*of
) {
3771 _cleanup_close_
int fd
= -EBADF
, ofd
= -EBADF
;
3777 ofd
= open(of
->path
, O_PATH
| O_CLOEXEC
);
3779 return log_exec_error_errno(c
, p
, errno
, "Could not open \"%s\": %m", of
->path
);
3781 if (fstat(ofd
, &st
) < 0)
3782 return log_exec_error_errno(c
, p
, errno
, "Failed to stat %s: %m", of
->path
);
3784 if (S_ISSOCK(st
.st_mode
)) {
3785 fd
= connect_unix_harder(c
, p
, of
, ofd
);
3789 if (FLAGS_SET(of
->flags
, OPENFILE_READ_ONLY
) && shutdown(fd
, SHUT_WR
) < 0)
3790 return log_exec_error_errno(c
, p
, errno
, "Failed to shutdown send for socket %s: %m",
3793 log_exec_debug(c
, p
, "socket %s opened (fd=%d)", of
->path
, fd
);
3795 int flags
= FLAGS_SET(of
->flags
, OPENFILE_READ_ONLY
) ? O_RDONLY
: O_RDWR
;
3796 if (FLAGS_SET(of
->flags
, OPENFILE_APPEND
))
3798 else if (FLAGS_SET(of
->flags
, OPENFILE_TRUNCATE
))
3801 fd
= fd_reopen(ofd
, flags
| O_CLOEXEC
);
3803 return log_exec_error_errno(c
, p
, fd
, "Failed to open file %s: %m", of
->path
);
3805 log_exec_debug(c
, p
, "file %s opened (fd=%d)", of
->path
, fd
);
3811 static int collect_open_file_fds(const ExecContext
*c
, ExecParameters
*p
, size_t *n_fds
) {
3818 LIST_FOREACH(open_files
, of
, p
->open_files
) {
3819 _cleanup_close_
int fd
= -EBADF
;
3821 fd
= get_open_file_fd(c
, p
, of
);
3823 if (FLAGS_SET(of
->flags
, OPENFILE_GRACEFUL
)) {
3824 log_exec_debug_errno(c
, p
, fd
, "Failed to get OpenFile= file descriptor for %s, ignoring: %m", of
->path
);
3831 if (!GREEDY_REALLOC(p
->fds
, *n_fds
+ 1))
3834 r
= strv_extend(&p
->fd_names
, of
->fdname
);
3838 p
->fds
[*n_fds
] = TAKE_FD(fd
);
3846 static void log_command_line(
3847 const ExecContext
*context
,
3848 const ExecParameters
*params
,
3850 const char *executable
,
3861 _cleanup_free_
char *cmdline
= quote_command_line(argv
, SHELL_ESCAPE_EMPTY
);
3863 log_exec_struct(context
, params
, LOG_DEBUG
,
3864 "EXECUTABLE=%s", executable
,
3865 LOG_EXEC_MESSAGE(params
, "%s: %s", msg
, strnull(cmdline
)),
3866 LOG_EXEC_INVOCATION_ID(params
));
3869 static bool exec_context_need_unprivileged_private_users(
3870 const ExecContext
*context
,
3871 const ExecParameters
*params
) {
3876 /* These options require PrivateUsers= when used in user units, as we need to be in a user namespace
3877 * to have permission to enable them when not running as root. If we have effective CAP_SYS_ADMIN
3878 * (system manager) then we have privileges and don't need this. */
3879 if (params
->runtime_scope
!= RUNTIME_SCOPE_USER
)
3882 return context
->private_users
||
3883 context
->private_tmp
||
3884 context
->private_devices
||
3885 context
->private_network
||
3886 context
->network_namespace_path
||
3887 context
->private_ipc
||
3888 context
->ipc_namespace_path
||
3889 context
->private_mounts
> 0 ||
3890 context
->mount_apivfs
||
3891 context
->n_bind_mounts
> 0 ||
3892 context
->n_temporary_filesystems
> 0 ||
3893 context
->root_directory
||
3894 !strv_isempty(context
->extension_directories
) ||
3895 context
->protect_system
!= PROTECT_SYSTEM_NO
||
3896 context
->protect_home
!= PROTECT_HOME_NO
||
3897 context
->protect_kernel_tunables
||
3898 context
->protect_kernel_modules
||
3899 context
->protect_kernel_logs
||
3900 context
->protect_control_groups
||
3901 context
->protect_clock
||
3902 context
->protect_hostname
||
3903 !strv_isempty(context
->read_write_paths
) ||
3904 !strv_isempty(context
->read_only_paths
) ||
3905 !strv_isempty(context
->inaccessible_paths
) ||
3906 !strv_isempty(context
->exec_paths
) ||
3907 !strv_isempty(context
->no_exec_paths
);
3910 static bool exec_context_shall_confirm_spawn(const ExecContext
*context
) {
3913 if (confirm_spawn_disabled())
3916 /* For some reasons units remaining in the same process group
3917 * as PID 1 fail to acquire the console even if it's not used
3918 * by any process. So skip the confirmation question for them. */
3919 return !context
->same_pgrp
;
3922 static int exec_context_named_iofds(
3923 const ExecContext
*c
,
3924 const ExecParameters
*p
,
3925 int named_iofds
[static 3]) {
3928 const char* stdio_fdname
[3];
3933 assert(named_iofds
);
3935 targets
= (c
->std_input
== EXEC_INPUT_NAMED_FD
) +
3936 (c
->std_output
== EXEC_OUTPUT_NAMED_FD
) +
3937 (c
->std_error
== EXEC_OUTPUT_NAMED_FD
);
3939 for (size_t i
= 0; i
< 3; i
++)
3940 stdio_fdname
[i
] = exec_context_fdname(c
, i
);
3942 n_fds
= p
->n_storage_fds
+ p
->n_socket_fds
;
3944 for (size_t i
= 0; i
< n_fds
&& targets
> 0; i
++)
3945 if (named_iofds
[STDIN_FILENO
] < 0 &&
3946 c
->std_input
== EXEC_INPUT_NAMED_FD
&&
3947 stdio_fdname
[STDIN_FILENO
] &&
3948 streq(p
->fd_names
[i
], stdio_fdname
[STDIN_FILENO
])) {
3950 named_iofds
[STDIN_FILENO
] = p
->fds
[i
];
3953 } else if (named_iofds
[STDOUT_FILENO
] < 0 &&
3954 c
->std_output
== EXEC_OUTPUT_NAMED_FD
&&
3955 stdio_fdname
[STDOUT_FILENO
] &&
3956 streq(p
->fd_names
[i
], stdio_fdname
[STDOUT_FILENO
])) {
3958 named_iofds
[STDOUT_FILENO
] = p
->fds
[i
];
3961 } else if (named_iofds
[STDERR_FILENO
] < 0 &&
3962 c
->std_error
== EXEC_OUTPUT_NAMED_FD
&&
3963 stdio_fdname
[STDERR_FILENO
] &&
3964 streq(p
->fd_names
[i
], stdio_fdname
[STDERR_FILENO
])) {
3966 named_iofds
[STDERR_FILENO
] = p
->fds
[i
];
3970 return targets
== 0 ? 0 : -ENOENT
;
3973 static void exec_shared_runtime_close(ExecSharedRuntime
*shared
) {
3977 safe_close_pair(shared
->netns_storage_socket
);
3978 safe_close_pair(shared
->ipcns_storage_socket
);
3981 static void exec_runtime_close(ExecRuntime
*rt
) {
3985 safe_close_pair(rt
->ephemeral_storage_socket
);
3987 exec_shared_runtime_close(rt
->shared
);
3988 dynamic_creds_close(rt
->dynamic_creds
);
3991 static void exec_params_close(ExecParameters
*p
) {
3995 p
->stdin_fd
= safe_close(p
->stdin_fd
);
3996 p
->stdout_fd
= safe_close(p
->stdout_fd
);
3997 p
->stderr_fd
= safe_close(p
->stderr_fd
);
4001 const ExecCommand
*command
,
4002 const ExecContext
*context
,
4003 ExecParameters
*params
,
4004 ExecRuntime
*runtime
,
4005 const CGroupContext
*cgroup_context
,
4008 _cleanup_strv_free_
char **our_env
= NULL
, **pass_env
= NULL
, **joined_exec_search_path
= NULL
, **accum_env
= NULL
, **replaced_argv
= NULL
;
4010 _cleanup_free_ gid_t
*supplementary_gids
= NULL
;
4011 const char *username
= NULL
, *groupname
= NULL
;
4012 _cleanup_free_
char *home_buffer
= NULL
, *memory_pressure_path
= NULL
;
4013 const char *home
= NULL
, *shell
= NULL
;
4014 char **final_argv
= NULL
;
4015 dev_t journal_stream_dev
= 0;
4016 ino_t journal_stream_ino
= 0;
4017 bool userns_set_up
= false;
4018 bool needs_sandboxing
, /* Do we need to set up full sandboxing? (i.e. all namespacing, all MAC stuff, caps, yadda yadda */
4019 needs_setuid
, /* Do we need to do the actual setresuid()/setresgid() calls? */
4020 needs_mount_namespace
, /* Do we need to set up a mount namespace for this kernel? */
4021 needs_ambient_hack
; /* Do we need to apply the ambient capabilities hack? */
4022 bool keep_seccomp_privileges
= false;
4024 _cleanup_free_
char *mac_selinux_context_net
= NULL
;
4025 bool use_selinux
= false;
4028 bool use_smack
= false;
4031 bool use_apparmor
= false;
4034 uint64_t saved_bset
= 0;
4036 uid_t saved_uid
= getuid();
4037 gid_t saved_gid
= getgid();
4038 uid_t uid
= UID_INVALID
;
4039 gid_t gid
= GID_INVALID
;
4040 size_t n_fds
, /* fds to pass to the child */
4041 n_keep_fds
; /* total number of fds not to close */
4043 _cleanup_free_ gid_t
*gids_after_pam
= NULL
;
4044 int ngids_after_pam
= 0;
4046 int socket_fd
= -EBADF
, named_iofds
[3] = EBADF_TRIPLET
;
4047 size_t n_storage_fds
, n_socket_fds
;
4052 assert(exit_status
);
4054 /* This should be mostly redundant, as the log level is also passed as an argument of the executor,
4055 * and is already applied earlier. Just for safety. */
4056 if (context
->log_level_max
>= 0)
4057 log_set_max_level(context
->log_level_max
);
4059 /* Explicitly test for CVE-2021-4034 inspired invocations */
4060 if (!command
->path
|| strv_isempty(command
->argv
)) {
4061 *exit_status
= EXIT_EXEC
;
4062 return log_exec_error_errno(
4065 SYNTHETIC_ERRNO(EINVAL
),
4066 "Invalid command line arguments.");
4069 LOG_CONTEXT_PUSH_EXEC(context
, params
);
4071 if (context
->std_input
== EXEC_INPUT_SOCKET
||
4072 context
->std_output
== EXEC_OUTPUT_SOCKET
||
4073 context
->std_error
== EXEC_OUTPUT_SOCKET
) {
4075 if (params
->n_socket_fds
> 1)
4076 return log_exec_error_errno(context
, params
, SYNTHETIC_ERRNO(EINVAL
), "Got more than one socket.");
4078 if (params
->n_socket_fds
== 0)
4079 return log_exec_error_errno(context
, params
, SYNTHETIC_ERRNO(EINVAL
), "Got no socket.");
4081 socket_fd
= params
->fds
[0];
4082 n_storage_fds
= n_socket_fds
= 0;
4084 n_socket_fds
= params
->n_socket_fds
;
4085 n_storage_fds
= params
->n_storage_fds
;
4087 n_fds
= n_socket_fds
+ n_storage_fds
;
4089 r
= exec_context_named_iofds(context
, params
, named_iofds
);
4091 return log_exec_error_errno(context
, params
, r
, "Failed to load a named file descriptor: %m");
4093 rename_process_from_path(command
->path
);
4095 /* We reset exactly these signals, since they are the only ones we set to SIG_IGN in the main
4096 * daemon. All others we leave untouched because we set them to SIG_DFL or a valid handler initially,
4097 * both of which will be demoted to SIG_DFL. */
4098 (void) default_signals(SIGNALS_CRASH_HANDLER
,
4101 if (context
->ignore_sigpipe
)
4102 (void) ignore_signals(SIGPIPE
);
4104 r
= reset_signal_mask();
4106 *exit_status
= EXIT_SIGNAL_MASK
;
4107 return log_exec_error_errno(context
, params
, r
, "Failed to set process signal mask: %m");
4110 if (params
->idle_pipe
)
4111 do_idle_pipe_dance(params
->idle_pipe
);
4113 /* Close fds we don't need very early to make sure we don't block init reexecution because it cannot bind its
4114 * sockets. Among the fds we close are the logging fds, and we want to keep them closed, so that we don't have
4115 * any fds open we don't really want open during the transition. In order to make logging work, we switch the
4116 * log subsystem into open_when_needed mode, so that it reopens the logs on every single log call. */
4119 log_set_open_when_needed(true);
4120 log_settle_target();
4122 /* In case anything used libc syslog(), close this here, too */
4125 r
= collect_open_file_fds(context
, params
, &n_fds
);
4127 *exit_status
= EXIT_FDS
;
4128 return log_exec_error_errno(context
, params
, r
, "Failed to get OpenFile= file descriptors: %m");
4131 int keep_fds
[n_fds
+ 3];
4132 memcpy_safe(keep_fds
, params
->fds
, n_fds
* sizeof(int));
4135 r
= add_shifted_fd(keep_fds
, ELEMENTSOF(keep_fds
), &n_keep_fds
, ¶ms
->exec_fd
);
4137 *exit_status
= EXIT_FDS
;
4138 return log_exec_error_errno(context
, params
, r
, "Failed to collect shifted fd: %m");
4142 r
= add_shifted_fd(keep_fds
, ELEMENTSOF(keep_fds
), &n_keep_fds
, ¶ms
->bpf_outer_map_fd
);
4144 *exit_status
= EXIT_FDS
;
4145 return log_exec_error_errno(context
, params
, r
, "Failed to collect shifted fd: %m");
4149 r
= close_remaining_fds(params
, runtime
, socket_fd
, keep_fds
, n_keep_fds
);
4151 *exit_status
= EXIT_FDS
;
4152 return log_exec_error_errno(context
, params
, r
, "Failed to close unwanted file descriptors: %m");
4155 if (!context
->same_pgrp
&&
4157 *exit_status
= EXIT_SETSID
;
4158 return log_exec_error_errno(context
, params
, errno
, "Failed to create new process session: %m");
4161 exec_context_tty_reset(context
, params
);
4163 if (params
->shall_confirm_spawn
&& exec_context_shall_confirm_spawn(context
)) {
4164 _cleanup_free_
char *cmdline
= NULL
;
4166 cmdline
= quote_command_line(command
->argv
, SHELL_ESCAPE_EMPTY
);
4168 *exit_status
= EXIT_MEMORY
;
4172 r
= ask_for_confirmation(context
, params
, cmdline
);
4173 if (r
!= CONFIRM_EXECUTE
) {
4174 if (r
== CONFIRM_PRETEND_SUCCESS
) {
4175 *exit_status
= EXIT_SUCCESS
;
4179 *exit_status
= EXIT_CONFIRM
;
4180 return log_exec_error_errno(context
, params
, SYNTHETIC_ERRNO(ECANCELED
),
4181 "Execution cancelled by the user");
4185 /* We are about to invoke NSS and PAM modules. Let's tell them what we are doing here, maybe they care. This is
4186 * used by nss-resolve to disable itself when we are about to start systemd-resolved, to avoid deadlocks. Note
4187 * that these env vars do not survive the execve(), which means they really only apply to the PAM and NSS
4188 * invocations themselves. Also note that while we'll only invoke NSS modules involved in user management they
4189 * might internally call into other NSS modules that are involved in hostname resolution, we never know. */
4190 if (setenv("SYSTEMD_ACTIVATION_UNIT", params
->unit_id
, true) != 0 ||
4191 setenv("SYSTEMD_ACTIVATION_SCOPE", runtime_scope_to_string(params
->runtime_scope
), true) != 0) {
4192 *exit_status
= EXIT_MEMORY
;
4193 return log_exec_error_errno(context
, params
, errno
, "Failed to update environment: %m");
4196 if (context
->dynamic_user
&& runtime
&& runtime
->dynamic_creds
) {
4197 _cleanup_strv_free_
char **suggested_paths
= NULL
;
4199 /* On top of that, make sure we bypass our own NSS module nss-systemd comprehensively for any NSS
4200 * checks, if DynamicUser=1 is used, as we shouldn't create a feedback loop with ourselves here. */
4201 if (putenv((char*) "SYSTEMD_NSS_DYNAMIC_BYPASS=1") != 0) {
4202 *exit_status
= EXIT_USER
;
4203 return log_exec_error_errno(context
, params
, errno
, "Failed to update environment: %m");
4206 r
= compile_suggested_paths(context
, params
, &suggested_paths
);
4208 *exit_status
= EXIT_MEMORY
;
4212 r
= dynamic_creds_realize(runtime
->dynamic_creds
, suggested_paths
, &uid
, &gid
);
4214 *exit_status
= EXIT_USER
;
4216 return log_exec_error_errno(context
, params
, SYNTHETIC_ERRNO(EOPNOTSUPP
),
4217 "Failed to update dynamic user credentials: User or group with specified name already exists.");
4218 return log_exec_error_errno(context
, params
, r
, "Failed to update dynamic user credentials: %m");
4221 if (!uid_is_valid(uid
)) {
4222 *exit_status
= EXIT_USER
;
4223 return log_exec_error_errno(context
, params
, SYNTHETIC_ERRNO(ESRCH
), "UID validation failed for \""UID_FMT
"\"", uid
);
4226 if (!gid_is_valid(gid
)) {
4227 *exit_status
= EXIT_USER
;
4228 return log_exec_error_errno(context
, params
, SYNTHETIC_ERRNO(ESRCH
), "GID validation failed for \""GID_FMT
"\"", gid
);
4231 if (runtime
->dynamic_creds
->user
)
4232 username
= runtime
->dynamic_creds
->user
->name
;
4235 if (context
->user
) {
4236 r
= get_fixed_user(context
->user
, &username
, &uid
, &gid
, &home
, &shell
);
4238 *exit_status
= EXIT_USER
;
4239 return log_exec_error_errno(context
, params
, r
, "Failed to determine user credentials: %m");
4243 if (context
->group
) {
4244 r
= get_fixed_group(context
->group
, &groupname
, &gid
);
4246 *exit_status
= EXIT_GROUP
;
4247 return log_exec_error_errno(context
, params
, r
, "Failed to determine group credentials: %m");
4252 /* Initialize user supplementary groups and get SupplementaryGroups= ones */
4253 r
= get_supplementary_groups(context
, username
, groupname
, gid
,
4254 &supplementary_gids
, &ngids
);
4256 *exit_status
= EXIT_GROUP
;
4257 return log_exec_error_errno(context
, params
, r
, "Failed to determine supplementary groups: %m");
4260 r
= send_user_lookup(params
->unit_id
, params
->user_lookup_fd
, uid
, gid
);
4262 *exit_status
= EXIT_USER
;
4263 return log_exec_error_errno(context
, params
, r
, "Failed to send user credentials to PID1: %m");
4266 params
->user_lookup_fd
= safe_close(params
->user_lookup_fd
);
4268 r
= acquire_home(context
, uid
, &home
, &home_buffer
);
4270 *exit_status
= EXIT_CHDIR
;
4271 return log_exec_error_errno(context
, params
, r
, "Failed to determine $HOME for user: %m");
4274 /* If a socket is connected to STDIN/STDOUT/STDERR, we must drop O_NONBLOCK */
4276 (void) fd_nonblock(socket_fd
, false);
4278 /* Journald will try to look-up our cgroup in order to populate _SYSTEMD_CGROUP and _SYSTEMD_UNIT fields.
4279 * Hence we need to migrate to the target cgroup from init.scope before connecting to journald */
4280 if (params
->cgroup_path
) {
4281 _cleanup_free_
char *p
= NULL
;
4283 r
= exec_params_get_cgroup_path(params
, cgroup_context
, &p
);
4285 *exit_status
= EXIT_CGROUP
;
4286 return log_exec_error_errno(context
, params
, r
, "Failed to acquire cgroup path: %m");
4289 r
= cg_attach_everywhere(params
->cgroup_supported
, p
, 0, NULL
, NULL
);
4290 if (r
== -EUCLEAN
) {
4291 *exit_status
= EXIT_CGROUP
;
4292 return log_exec_error_errno(context
, params
, r
, "Failed to attach process to cgroup %s "
4293 "because the cgroup or one of its parents or "
4294 "siblings is in the threaded mode: %m", p
);
4297 *exit_status
= EXIT_CGROUP
;
4298 return log_exec_error_errno(context
, params
, r
, "Failed to attach to cgroup %s: %m", p
);
4302 if (context
->network_namespace_path
&& runtime
&& runtime
->shared
&& runtime
->shared
->netns_storage_socket
[0] >= 0) {
4303 r
= open_shareable_ns_path(runtime
->shared
->netns_storage_socket
, context
->network_namespace_path
, CLONE_NEWNET
);
4305 *exit_status
= EXIT_NETWORK
;
4306 return log_exec_error_errno(context
, params
, r
, "Failed to open network namespace path %s: %m", context
->network_namespace_path
);
4310 if (context
->ipc_namespace_path
&& runtime
&& runtime
->shared
&& runtime
->shared
->ipcns_storage_socket
[0] >= 0) {
4311 r
= open_shareable_ns_path(runtime
->shared
->ipcns_storage_socket
, context
->ipc_namespace_path
, CLONE_NEWIPC
);
4313 *exit_status
= EXIT_NAMESPACE
;
4314 return log_exec_error_errno(context
, params
, r
, "Failed to open IPC namespace path %s: %m", context
->ipc_namespace_path
);
4318 r
= setup_input(context
, params
, socket_fd
, named_iofds
);
4320 *exit_status
= EXIT_STDIN
;
4321 return log_exec_error_errno(context
, params
, r
, "Failed to set up standard input: %m");
4324 r
= setup_output(context
, params
, STDOUT_FILENO
, socket_fd
, named_iofds
, basename(command
->path
), uid
, gid
, &journal_stream_dev
, &journal_stream_ino
);
4326 *exit_status
= EXIT_STDOUT
;
4327 return log_exec_error_errno(context
, params
, r
, "Failed to set up standard output: %m");
4330 r
= setup_output(context
, params
, STDERR_FILENO
, socket_fd
, named_iofds
, basename(command
->path
), uid
, gid
, &journal_stream_dev
, &journal_stream_ino
);
4332 *exit_status
= EXIT_STDERR
;
4333 return log_exec_error_errno(context
, params
, r
, "Failed to set up standard error output: %m");
4336 if (context
->oom_score_adjust_set
) {
4337 /* When we can't make this change due to EPERM, then let's silently skip over it. User
4338 * namespaces prohibit write access to this file, and we shouldn't trip up over that. */
4339 r
= set_oom_score_adjust(context
->oom_score_adjust
);
4340 if (ERRNO_IS_NEG_PRIVILEGE(r
))
4341 log_exec_debug_errno(context
, params
, r
,
4342 "Failed to adjust OOM setting, assuming containerized execution, ignoring: %m");
4344 *exit_status
= EXIT_OOM_ADJUST
;
4345 return log_exec_error_errno(context
, params
, r
, "Failed to adjust OOM setting: %m");
4349 if (context
->coredump_filter_set
) {
4350 r
= set_coredump_filter(context
->coredump_filter
);
4351 if (ERRNO_IS_NEG_PRIVILEGE(r
))
4352 log_exec_debug_errno(context
, params
, r
, "Failed to adjust coredump_filter, ignoring: %m");
4354 *exit_status
= EXIT_LIMITS
;
4355 return log_exec_error_errno(context
, params
, r
, "Failed to adjust coredump_filter: %m");
4359 if (context
->nice_set
) {
4360 r
= setpriority_closest(context
->nice
);
4362 *exit_status
= EXIT_NICE
;
4363 return log_exec_error_errno(context
, params
, r
, "Failed to set up process scheduling priority (nice level): %m");
4367 if (context
->cpu_sched_set
) {
4368 struct sched_param param
= {
4369 .sched_priority
= context
->cpu_sched_priority
,
4372 r
= sched_setscheduler(0,
4373 context
->cpu_sched_policy
|
4374 (context
->cpu_sched_reset_on_fork
?
4375 SCHED_RESET_ON_FORK
: 0),
4378 *exit_status
= EXIT_SETSCHEDULER
;
4379 return log_exec_error_errno(context
, params
, errno
, "Failed to set up CPU scheduling: %m");
4383 if (context
->cpu_affinity_from_numa
|| context
->cpu_set
.set
) {
4384 _cleanup_(cpu_set_reset
) CPUSet converted_cpu_set
= {};
4385 const CPUSet
*cpu_set
;
4387 if (context
->cpu_affinity_from_numa
) {
4388 r
= exec_context_cpu_affinity_from_numa(context
, &converted_cpu_set
);
4390 *exit_status
= EXIT_CPUAFFINITY
;
4391 return log_exec_error_errno(context
, params
, r
, "Failed to derive CPU affinity mask from NUMA mask: %m");
4394 cpu_set
= &converted_cpu_set
;
4396 cpu_set
= &context
->cpu_set
;
4398 if (sched_setaffinity(0, cpu_set
->allocated
, cpu_set
->set
) < 0) {
4399 *exit_status
= EXIT_CPUAFFINITY
;
4400 return log_exec_error_errno(context
, params
, errno
, "Failed to set up CPU affinity: %m");
4404 if (mpol_is_valid(numa_policy_get_type(&context
->numa_policy
))) {
4405 r
= apply_numa_policy(&context
->numa_policy
);
4406 if (ERRNO_IS_NEG_NOT_SUPPORTED(r
))
4407 log_exec_debug_errno(context
, params
, r
, "NUMA support not available, ignoring.");
4409 *exit_status
= EXIT_NUMA_POLICY
;
4410 return log_exec_error_errno(context
, params
, r
, "Failed to set NUMA memory policy: %m");
4414 if (context
->ioprio_set
)
4415 if (ioprio_set(IOPRIO_WHO_PROCESS
, 0, context
->ioprio
) < 0) {
4416 *exit_status
= EXIT_IOPRIO
;
4417 return log_exec_error_errno(context
, params
, errno
, "Failed to set up IO scheduling priority: %m");
4420 if (context
->timer_slack_nsec
!= NSEC_INFINITY
)
4421 if (prctl(PR_SET_TIMERSLACK
, context
->timer_slack_nsec
) < 0) {
4422 *exit_status
= EXIT_TIMERSLACK
;
4423 return log_exec_error_errno(context
, params
, errno
, "Failed to set up timer slack: %m");
4426 if (context
->personality
!= PERSONALITY_INVALID
) {
4427 r
= safe_personality(context
->personality
);
4429 *exit_status
= EXIT_PERSONALITY
;
4430 return log_exec_error_errno(context
, params
, r
, "Failed to set up execution domain (personality): %m");
4435 if (context
->utmp_id
) {
4436 const char *line
= context
->tty_path
?
4437 (path_startswith(context
->tty_path
, "/dev/") ?: context
->tty_path
) :
4439 utmp_put_init_process(context
->utmp_id
, getpid_cached(), getsid(0),
4441 context
->utmp_mode
== EXEC_UTMP_INIT
? INIT_PROCESS
:
4442 context
->utmp_mode
== EXEC_UTMP_LOGIN
? LOGIN_PROCESS
:
4448 if (uid_is_valid(uid
)) {
4449 r
= chown_terminal(STDIN_FILENO
, uid
);
4451 *exit_status
= EXIT_STDIN
;
4452 return log_exec_error_errno(context
, params
, r
, "Failed to change ownership of terminal: %m");
4456 if (params
->cgroup_path
) {
4457 /* If delegation is enabled we'll pass ownership of the cgroup to the user of the new process. On cgroup v1
4458 * this is only about systemd's own hierarchy, i.e. not the controller hierarchies, simply because that's not
4459 * safe. On cgroup v2 there's only one hierarchy anyway, and delegation is safe there, hence in that case only
4460 * touch a single hierarchy too. */
4462 if (params
->flags
& EXEC_CGROUP_DELEGATE
) {
4463 _cleanup_free_
char *p
= NULL
;
4465 r
= cg_set_access(SYSTEMD_CGROUP_CONTROLLER
, params
->cgroup_path
, uid
, gid
);
4467 *exit_status
= EXIT_CGROUP
;
4468 return log_exec_error_errno(context
, params
, r
, "Failed to adjust control group access: %m");
4471 r
= exec_params_get_cgroup_path(params
, cgroup_context
, &p
);
4473 *exit_status
= EXIT_CGROUP
;
4474 return log_exec_error_errno(context
, params
, r
, "Failed to acquire cgroup path: %m");
4477 r
= cg_set_access_recursive(SYSTEMD_CGROUP_CONTROLLER
, p
, uid
, gid
);
4479 *exit_status
= EXIT_CGROUP
;
4480 return log_exec_error_errno(context
, params
, r
, "Failed to adjust control subgroup access: %m");
4485 if (cgroup_context
&& cg_unified() > 0 && is_pressure_supported() > 0) {
4486 if (cgroup_context_want_memory_pressure(cgroup_context
)) {
4487 r
= cg_get_path("memory", params
->cgroup_path
, "memory.pressure", &memory_pressure_path
);
4489 *exit_status
= EXIT_MEMORY
;
4493 r
= chmod_and_chown(memory_pressure_path
, 0644, uid
, gid
);
4495 log_exec_full_errno(context
, params
, r
== -ENOENT
|| ERRNO_IS_PRIVILEGE(r
) ? LOG_DEBUG
: LOG_WARNING
, r
,
4496 "Failed to adjust ownership of '%s', ignoring: %m", memory_pressure_path
);
4497 memory_pressure_path
= mfree(memory_pressure_path
);
4499 } else if (cgroup_context
->memory_pressure_watch
== CGROUP_PRESSURE_WATCH_OFF
) {
4500 memory_pressure_path
= strdup("/dev/null"); /* /dev/null is explicit indicator for turning of memory pressure watch */
4501 if (!memory_pressure_path
) {
4502 *exit_status
= EXIT_MEMORY
;
4509 needs_mount_namespace
= exec_needs_mount_namespace(context
, params
, runtime
);
4511 for (ExecDirectoryType dt
= 0; dt
< _EXEC_DIRECTORY_TYPE_MAX
; dt
++) {
4512 r
= setup_exec_directory(context
, params
, uid
, gid
, dt
, needs_mount_namespace
, exit_status
);
4514 return log_exec_error_errno(context
, params
, r
, "Failed to set up special execution directory in %s: %m", params
->prefix
[dt
]);
4517 if (FLAGS_SET(params
->flags
, EXEC_WRITE_CREDENTIALS
)) {
4518 r
= exec_setup_credentials(context
, params
, params
->unit_id
, uid
, gid
);
4520 *exit_status
= EXIT_CREDENTIALS
;
4521 return log_exec_error_errno(context
, params
, r
, "Failed to set up credentials: %m");
4525 r
= build_environment(
4535 memory_pressure_path
,
4538 *exit_status
= EXIT_MEMORY
;
4542 r
= build_pass_environment(context
, &pass_env
);
4544 *exit_status
= EXIT_MEMORY
;
4548 /* The $PATH variable is set to the default path in params->environment. However, this is overridden
4549 * if user-specified fields have $PATH set. The intention is to also override $PATH if the unit does
4550 * not specify PATH but the unit has ExecSearchPath. */
4551 if (!strv_isempty(context
->exec_search_path
)) {
4552 _cleanup_free_
char *joined
= NULL
;
4554 joined
= strv_join(context
->exec_search_path
, ":");
4556 *exit_status
= EXIT_MEMORY
;
4560 r
= strv_env_assign(&joined_exec_search_path
, "PATH", joined
);
4562 *exit_status
= EXIT_MEMORY
;
4567 accum_env
= strv_env_merge(params
->environment
,
4569 joined_exec_search_path
,
4571 context
->environment
,
4574 *exit_status
= EXIT_MEMORY
;
4577 accum_env
= strv_env_clean(accum_env
);
4579 (void) umask(context
->umask
);
4581 r
= setup_keyring(context
, params
, uid
, gid
);
4583 *exit_status
= EXIT_KEYRING
;
4584 return log_exec_error_errno(context
, params
, r
, "Failed to set up kernel keyring: %m");
4587 /* We need sandboxing if the caller asked us to apply it and the command isn't explicitly excepted
4589 needs_sandboxing
= (params
->flags
& EXEC_APPLY_SANDBOXING
) && !(command
->flags
& EXEC_COMMAND_FULLY_PRIVILEGED
);
4591 /* We need the ambient capability hack, if the caller asked us to apply it and the command is marked
4592 * for it, and the kernel doesn't actually support ambient caps. */
4593 needs_ambient_hack
= (params
->flags
& EXEC_APPLY_SANDBOXING
) && (command
->flags
& EXEC_COMMAND_AMBIENT_MAGIC
) && !ambient_capabilities_supported();
4595 /* We need setresuid() if the caller asked us to apply sandboxing and the command isn't explicitly
4596 * excepted from either whole sandboxing or just setresuid() itself, and the ambient hack is not
4598 if (needs_ambient_hack
)
4599 needs_setuid
= false;
4601 needs_setuid
= (params
->flags
& EXEC_APPLY_SANDBOXING
) && !(command
->flags
& (EXEC_COMMAND_FULLY_PRIVILEGED
|EXEC_COMMAND_NO_SETUID
));
4603 uint64_t capability_ambient_set
= context
->capability_ambient_set
;
4605 if (needs_sandboxing
) {
4606 /* MAC enablement checks need to be done before a new mount ns is created, as they rely on
4607 * /sys being present. The actual MAC context application will happen later, as late as
4608 * possible, to avoid impacting our own code paths. */
4611 use_selinux
= mac_selinux_use();
4614 use_smack
= mac_smack_use();
4617 use_apparmor
= mac_apparmor_use();
4621 if (needs_sandboxing
) {
4624 /* Let's set the resource limits before we call into PAM, so that pam_limits wins over what
4625 * is set here. (See below.) */
4627 r
= setrlimit_closest_all((const struct rlimit
* const *) context
->rlimit
, &which_failed
);
4629 *exit_status
= EXIT_LIMITS
;
4630 return log_exec_error_errno(context
, params
, r
, "Failed to adjust resource limit RLIMIT_%s: %m", rlimit_to_string(which_failed
));
4634 if (needs_setuid
&& context
->pam_name
&& username
) {
4635 /* Let's call into PAM after we set up our own idea of resource limits so that pam_limits
4636 * wins here. (See above.) */
4638 /* All fds passed in the fds array will be closed in the pam child process. */
4639 r
= setup_pam(context
->pam_name
, username
, uid
, gid
, context
->tty_path
, &accum_env
, params
->fds
, n_fds
, params
->exec_fd
);
4641 *exit_status
= EXIT_PAM
;
4642 return log_exec_error_errno(context
, params
, r
, "Failed to set up PAM session: %m");
4645 if (ambient_capabilities_supported()) {
4646 uint64_t ambient_after_pam
;
4648 /* PAM modules might have set some ambient caps. Query them here and merge them into
4649 * the caps we want to set in the end, so that we don't end up unsetting them. */
4650 r
= capability_get_ambient(&ambient_after_pam
);
4652 *exit_status
= EXIT_CAPABILITIES
;
4653 return log_exec_error_errno(context
, params
, r
, "Failed to query ambient caps: %m");
4656 capability_ambient_set
|= ambient_after_pam
;
4659 ngids_after_pam
= getgroups_alloc(&gids_after_pam
);
4660 if (ngids_after_pam
< 0) {
4661 *exit_status
= EXIT_GROUP
;
4662 return log_exec_error_errno(context
, params
, ngids_after_pam
, "Failed to obtain groups after setting up PAM: %m");
4666 if (needs_sandboxing
&& exec_context_need_unprivileged_private_users(context
, params
)) {
4667 /* If we're unprivileged, set up the user namespace first to enable use of the other namespaces.
4668 * Users with CAP_SYS_ADMIN can set up user namespaces last because they will be able to
4669 * set up all of the other namespaces (i.e. network, mount, UTS) without a user namespace. */
4671 r
= setup_private_users(saved_uid
, saved_gid
, uid
, gid
);
4672 /* If it was requested explicitly and we can't set it up, fail early. Otherwise, continue and let
4673 * the actual requested operations fail (or silently continue). */
4674 if (r
< 0 && context
->private_users
) {
4675 *exit_status
= EXIT_USER
;
4676 return log_exec_error_errno(context
, params
, r
, "Failed to set up user namespacing for unprivileged user: %m");
4679 log_exec_info_errno(context
, params
, r
, "Failed to set up user namespacing for unprivileged user, ignoring: %m");
4681 userns_set_up
= true;
4684 if (exec_needs_network_namespace(context
) && runtime
&& runtime
->shared
&& runtime
->shared
->netns_storage_socket
[0] >= 0) {
4686 /* Try to enable network namespacing if network namespacing is available and we have
4687 * CAP_NET_ADMIN. We need CAP_NET_ADMIN to be able to configure the loopback device in the
4688 * new network namespace. And if we don't have that, then we could only create a network
4689 * namespace without the ability to set up "lo". Hence gracefully skip things then. */
4690 if (ns_type_supported(NAMESPACE_NET
) && have_effective_cap(CAP_NET_ADMIN
) > 0) {
4691 r
= setup_shareable_ns(runtime
->shared
->netns_storage_socket
, CLONE_NEWNET
);
4692 if (ERRNO_IS_NEG_PRIVILEGE(r
))
4693 log_exec_notice_errno(context
, params
, r
,
4694 "PrivateNetwork=yes is configured, but network namespace setup not permitted, proceeding without: %m");
4696 *exit_status
= EXIT_NETWORK
;
4697 return log_exec_error_errno(context
, params
, r
, "Failed to set up network namespacing: %m");
4699 } else if (context
->network_namespace_path
) {
4700 *exit_status
= EXIT_NETWORK
;
4701 return log_exec_error_errno(context
, params
, SYNTHETIC_ERRNO(EOPNOTSUPP
),
4702 "NetworkNamespacePath= is not supported, refusing.");
4704 log_exec_notice(context
, params
, "PrivateNetwork=yes is configured, but the kernel does not support or we lack privileges for network namespace, proceeding without.");
4707 if (exec_needs_ipc_namespace(context
) && runtime
&& runtime
->shared
&& runtime
->shared
->ipcns_storage_socket
[0] >= 0) {
4709 if (ns_type_supported(NAMESPACE_IPC
)) {
4710 r
= setup_shareable_ns(runtime
->shared
->ipcns_storage_socket
, CLONE_NEWIPC
);
4712 log_exec_warning_errno(context
, params
, r
,
4713 "PrivateIPC=yes is configured, but IPC namespace setup failed, ignoring: %m");
4715 *exit_status
= EXIT_NAMESPACE
;
4716 return log_exec_error_errno(context
, params
, r
, "Failed to set up IPC namespacing: %m");
4718 } else if (context
->ipc_namespace_path
) {
4719 *exit_status
= EXIT_NAMESPACE
;
4720 return log_exec_error_errno(context
, params
, SYNTHETIC_ERRNO(EOPNOTSUPP
),
4721 "IPCNamespacePath= is not supported, refusing.");
4723 log_exec_warning(context
, params
, "PrivateIPC=yes is configured, but the kernel does not support IPC namespaces, ignoring.");
4726 if (needs_mount_namespace
) {
4727 _cleanup_free_
char *error_path
= NULL
;
4729 r
= apply_mount_namespace(command
->flags
, context
, params
, runtime
, memory_pressure_path
, &error_path
);
4731 *exit_status
= EXIT_NAMESPACE
;
4732 return log_exec_error_errno(context
, params
, r
, "Failed to set up mount namespacing%s%s: %m",
4733 error_path
? ": " : "", strempty(error_path
));
4737 if (needs_sandboxing
) {
4738 r
= apply_protect_hostname(context
, params
, exit_status
);
4743 if (context
->memory_ksm
>= 0)
4744 if (prctl(PR_SET_MEMORY_MERGE
, context
->memory_ksm
) < 0) {
4745 if (ERRNO_IS_NOT_SUPPORTED(errno
))
4746 log_exec_debug_errno(context
,
4749 "KSM support not available, ignoring.");
4751 *exit_status
= EXIT_KSM
;
4752 return log_exec_error_errno(context
, params
, errno
, "Failed to set KSM: %m");
4756 /* Drop groups as early as possible.
4757 * This needs to be done after PrivateDevices=yes setup as device nodes should be owned by the host's root.
4758 * For non-root in a userns, devices will be owned by the user/group before the group change, and nobody. */
4760 _cleanup_free_ gid_t
*gids_to_enforce
= NULL
;
4761 int ngids_to_enforce
= 0;
4763 ngids_to_enforce
= merge_gid_lists(supplementary_gids
,
4768 if (ngids_to_enforce
< 0) {
4769 *exit_status
= EXIT_GROUP
;
4770 return log_exec_error_errno(context
, params
,
4772 "Failed to merge group lists. Group membership might be incorrect: %m");
4775 r
= enforce_groups(gid
, gids_to_enforce
, ngids_to_enforce
);
4777 *exit_status
= EXIT_GROUP
;
4778 return log_exec_error_errno(context
, params
, r
, "Changing group credentials failed: %m");
4782 /* If the user namespace was not set up above, try to do it now.
4783 * It's preferred to set up the user namespace later (after all other namespaces) so as not to be
4784 * restricted by rules pertaining to combining user namespaces with other namespaces (e.g. in the
4785 * case of mount namespaces being less privileged when the mount point list is copied from a
4786 * different user namespace). */
4788 if (needs_sandboxing
&& context
->private_users
&& !userns_set_up
) {
4789 r
= setup_private_users(saved_uid
, saved_gid
, uid
, gid
);
4791 *exit_status
= EXIT_USER
;
4792 return log_exec_error_errno(context
, params
, r
, "Failed to set up user namespacing: %m");
4796 /* Now that the mount namespace has been set up and privileges adjusted, let's look for the thing we
4799 _cleanup_free_
char *executable
= NULL
;
4800 _cleanup_close_
int executable_fd
= -EBADF
;
4801 r
= find_executable_full(command
->path
, /* root= */ NULL
, context
->exec_search_path
, false, &executable
, &executable_fd
);
4803 if (r
!= -ENOMEM
&& (command
->flags
& EXEC_COMMAND_IGNORE_FAILURE
)) {
4804 log_exec_struct_errno(context
, params
, LOG_INFO
, r
,
4805 "MESSAGE_ID=" SD_MESSAGE_SPAWN_FAILED_STR
,
4806 LOG_EXEC_INVOCATION_ID(params
),
4807 LOG_EXEC_MESSAGE(params
,
4808 "Executable %s missing, skipping: %m",
4810 "EXECUTABLE=%s", command
->path
);
4811 *exit_status
= EXIT_SUCCESS
;
4815 *exit_status
= EXIT_EXEC
;
4816 return log_exec_struct_errno(context
, params
, LOG_INFO
, r
,
4817 "MESSAGE_ID=" SD_MESSAGE_SPAWN_FAILED_STR
,
4818 LOG_EXEC_INVOCATION_ID(params
),
4819 LOG_EXEC_MESSAGE(params
,
4820 "Failed to locate executable %s: %m",
4822 "EXECUTABLE=%s", command
->path
);
4825 r
= add_shifted_fd(keep_fds
, ELEMENTSOF(keep_fds
), &n_keep_fds
, &executable_fd
);
4827 *exit_status
= EXIT_FDS
;
4828 return log_exec_error_errno(context
, params
, r
, "Failed to collect shifted fd: %m");
4832 if (needs_sandboxing
&& use_selinux
&& params
->selinux_context_net
) {
4837 else if (params
->n_socket_fds
== 1)
4838 /* If stdin is not connected to a socket but we are triggered by exactly one socket unit then we
4839 * use context from that fd to compute the label. */
4840 fd
= params
->fds
[0];
4843 r
= mac_selinux_get_child_mls_label(fd
, executable
, context
->selinux_context
, &mac_selinux_context_net
);
4845 if (!context
->selinux_context_ignore
) {
4846 *exit_status
= EXIT_SELINUX_CONTEXT
;
4847 return log_exec_error_errno(context
,
4850 "Failed to determine SELinux context: %m");
4852 log_exec_debug_errno(context
,
4855 "Failed to determine SELinux context, ignoring: %m");
4861 /* We repeat the fd closing here, to make sure that nothing is leaked from the PAM modules. Note that
4862 * we are more aggressive this time, since we don't need socket_fd and the netns and ipcns fds any
4863 * more. We do keep exec_fd however, if we have it, since we need to keep it open until the final
4864 * execve(). But first, close the remaining sockets in the context objects. */
4866 exec_runtime_close(runtime
);
4867 exec_params_close(params
);
4869 r
= close_all_fds(keep_fds
, n_keep_fds
);
4871 r
= shift_fds(params
->fds
, n_fds
);
4873 r
= flag_fds(params
->fds
, n_socket_fds
, n_fds
, context
->non_blocking
);
4875 *exit_status
= EXIT_FDS
;
4876 return log_exec_error_errno(context
, params
, r
, "Failed to adjust passed file descriptors: %m");
4879 /* At this point, the fds we want to pass to the program are all ready and set up, with O_CLOEXEC turned off
4880 * and at the right fd numbers. The are no other fds open, with one exception: the exec_fd if it is defined,
4881 * and it has O_CLOEXEC set, after all we want it to be closed by the execve(), so that our parent knows we
4884 secure_bits
= context
->secure_bits
;
4886 if (needs_sandboxing
) {
4889 /* Set the RTPRIO resource limit to 0, but only if nothing else was explicitly requested.
4890 * (Note this is placed after the general resource limit initialization, see above, in order
4891 * to take precedence.) */
4892 if (context
->restrict_realtime
&& !context
->rlimit
[RLIMIT_RTPRIO
]) {
4893 if (setrlimit(RLIMIT_RTPRIO
, &RLIMIT_MAKE_CONST(0)) < 0) {
4894 *exit_status
= EXIT_LIMITS
;
4895 return log_exec_error_errno(context
, params
, errno
, "Failed to adjust RLIMIT_RTPRIO resource limit: %m");
4900 /* LSM Smack needs the capability CAP_MAC_ADMIN to change the current execution security context of the
4901 * process. This is the latest place before dropping capabilities. Other MAC context are set later. */
4902 if (use_smack
&& context
->smack_process_label
) {
4903 r
= setup_smack(params
, context
, executable_fd
);
4904 if (r
< 0 && !context
->smack_process_label_ignore
) {
4905 *exit_status
= EXIT_SMACK_PROCESS_LABEL
;
4906 return log_exec_error_errno(context
, params
, r
, "Failed to set SMACK process label: %m");
4911 bset
= context
->capability_bounding_set
;
4912 /* If the ambient caps hack is enabled (which means the kernel can't do them, and the user asked for
4913 * our magic fallback), then let's add some extra caps, so that the service can drop privs of its own,
4914 * instead of us doing that */
4915 if (needs_ambient_hack
)
4916 bset
|= (UINT64_C(1) << CAP_SETPCAP
) |
4917 (UINT64_C(1) << CAP_SETUID
) |
4918 (UINT64_C(1) << CAP_SETGID
);
4921 /* If the service has any form of a seccomp filter and it allows dropping privileges, we'll
4922 * keep the needed privileges to apply it even if we're not root. */
4924 uid_is_valid(uid
) &&
4925 context_has_seccomp(context
) &&
4926 seccomp_allows_drop_privileges(context
)) {
4927 keep_seccomp_privileges
= true;
4929 if (prctl(PR_SET_KEEPCAPS
, 1) < 0) {
4930 *exit_status
= EXIT_USER
;
4931 return log_exec_error_errno(context
, params
, errno
, "Failed to enable keep capabilities flag: %m");
4934 /* Save the current bounding set so we can restore it after applying the seccomp
4937 bset
|= (UINT64_C(1) << CAP_SYS_ADMIN
) |
4938 (UINT64_C(1) << CAP_SETPCAP
);
4942 if (!cap_test_all(bset
)) {
4943 r
= capability_bounding_set_drop(bset
, /* right_now= */ false);
4945 *exit_status
= EXIT_CAPABILITIES
;
4946 return log_exec_error_errno(context
, params
, r
, "Failed to drop capabilities: %m");
4950 /* Ambient capabilities are cleared during setresuid() (in enforce_user()) even with
4953 * To be able to raise the ambient capabilities after setresuid() they have to be added to
4954 * the inherited set and keep caps has to be set (done in enforce_user()). After setresuid()
4955 * the ambient capabilities can be raised as they are present in the permitted and
4956 * inhertiable set. However it is possible that someone wants to set ambient capabilities
4957 * without changing the user, so we also set the ambient capabilities here.
4959 * The requested ambient capabilities are raised in the inheritable set if the second
4960 * argument is true. */
4961 if (!needs_ambient_hack
) {
4962 r
= capability_ambient_set_apply(capability_ambient_set
, /* also_inherit= */ true);
4964 *exit_status
= EXIT_CAPABILITIES
;
4965 return log_exec_error_errno(context
, params
, r
, "Failed to apply ambient capabilities (before UID change): %m");
4970 /* chroot to root directory first, before we lose the ability to chroot */
4971 r
= apply_root_directory(context
, params
, runtime
, needs_mount_namespace
, exit_status
);
4973 return log_exec_error_errno(context
, params
, r
, "Chrooting to the requested root directory failed: %m");
4976 if (uid_is_valid(uid
)) {
4977 r
= enforce_user(context
, uid
, capability_ambient_set
);
4979 *exit_status
= EXIT_USER
;
4980 return log_exec_error_errno(context
, params
, r
, "Failed to change UID to " UID_FMT
": %m", uid
);
4983 if (keep_seccomp_privileges
) {
4984 if (!FLAGS_SET(capability_ambient_set
, (UINT64_C(1) << CAP_SETUID
))) {
4985 r
= drop_capability(CAP_SETUID
);
4987 *exit_status
= EXIT_USER
;
4988 return log_exec_error_errno(context
, params
, r
, "Failed to drop CAP_SETUID: %m");
4992 r
= keep_capability(CAP_SYS_ADMIN
);
4994 *exit_status
= EXIT_USER
;
4995 return log_exec_error_errno(context
, params
, r
, "Failed to keep CAP_SYS_ADMIN: %m");
4998 r
= keep_capability(CAP_SETPCAP
);
5000 *exit_status
= EXIT_USER
;
5001 return log_exec_error_errno(context
, params
, r
, "Failed to keep CAP_SETPCAP: %m");
5005 if (!needs_ambient_hack
&& capability_ambient_set
!= 0) {
5007 /* Raise the ambient capabilities after user change. */
5008 r
= capability_ambient_set_apply(capability_ambient_set
, /* also_inherit= */ false);
5010 *exit_status
= EXIT_CAPABILITIES
;
5011 return log_exec_error_errno(context
, params
, r
, "Failed to apply ambient capabilities (after UID change): %m");
5017 /* Apply working directory here, because the working directory might be on NFS and only the user running
5018 * this service might have the correct privilege to change to the working directory */
5019 r
= apply_working_directory(context
, params
, runtime
, home
, exit_status
);
5021 return log_exec_error_errno(context
, params
, r
, "Changing to the requested working directory failed: %m");
5023 if (needs_sandboxing
) {
5024 /* Apply other MAC contexts late, but before seccomp syscall filtering, as those should really be last to
5025 * influence our own codepaths as little as possible. Moreover, applying MAC contexts usually requires
5026 * syscalls that are subject to seccomp filtering, hence should probably be applied before the syscalls
5027 * are restricted. */
5031 char *exec_context
= mac_selinux_context_net
?: context
->selinux_context
;
5034 r
= setexeccon(exec_context
);
5036 if (!context
->selinux_context_ignore
) {
5037 *exit_status
= EXIT_SELINUX_CONTEXT
;
5038 return log_exec_error_errno(context
, params
, r
, "Failed to change SELinux context to %s: %m", exec_context
);
5040 log_exec_debug_errno(context
,
5043 "Failed to change SELinux context to %s, ignoring: %m",
5051 if (use_apparmor
&& context
->apparmor_profile
) {
5052 r
= aa_change_onexec(context
->apparmor_profile
);
5053 if (r
< 0 && !context
->apparmor_profile_ignore
) {
5054 *exit_status
= EXIT_APPARMOR_PROFILE
;
5055 return log_exec_error_errno(context
,
5058 "Failed to prepare AppArmor profile change to %s: %m",
5059 context
->apparmor_profile
);
5064 /* PR_GET_SECUREBITS is not privileged, while PR_SET_SECUREBITS is. So to suppress potential
5065 * EPERMs we'll try not to call PR_SET_SECUREBITS unless necessary. Setting securebits
5066 * requires CAP_SETPCAP. */
5067 if (prctl(PR_GET_SECUREBITS
) != secure_bits
) {
5068 /* CAP_SETPCAP is required to set securebits. This capability is raised into the
5069 * effective set here.
5071 * The effective set is overwritten during execve() with the following values:
5073 * - ambient set (for non-root processes)
5075 * - (inheritable | bounding) set for root processes)
5077 * Hence there is no security impact to raise it in the effective set before execve
5079 r
= capability_gain_cap_setpcap(/* return_caps= */ NULL
);
5081 *exit_status
= EXIT_CAPABILITIES
;
5082 return log_exec_error_errno(context
, params
, r
, "Failed to gain CAP_SETPCAP for setting secure bits");
5084 if (prctl(PR_SET_SECUREBITS
, secure_bits
) < 0) {
5085 *exit_status
= EXIT_SECUREBITS
;
5086 return log_exec_error_errno(context
, params
, errno
, "Failed to set process secure bits: %m");
5090 if (context_has_no_new_privileges(context
))
5091 if (prctl(PR_SET_NO_NEW_PRIVS
, 1, 0, 0, 0) < 0) {
5092 *exit_status
= EXIT_NO_NEW_PRIVILEGES
;
5093 return log_exec_error_errno(context
, params
, errno
, "Failed to disable new privileges: %m");
5097 r
= apply_address_families(context
, params
);
5099 *exit_status
= EXIT_ADDRESS_FAMILIES
;
5100 return log_exec_error_errno(context
, params
, r
, "Failed to restrict address families: %m");
5103 r
= apply_memory_deny_write_execute(context
, params
);
5105 *exit_status
= EXIT_SECCOMP
;
5106 return log_exec_error_errno(context
, params
, r
, "Failed to disable writing to executable memory: %m");
5109 r
= apply_restrict_realtime(context
, params
);
5111 *exit_status
= EXIT_SECCOMP
;
5112 return log_exec_error_errno(context
, params
, r
, "Failed to apply realtime restrictions: %m");
5115 r
= apply_restrict_suid_sgid(context
, params
);
5117 *exit_status
= EXIT_SECCOMP
;
5118 return log_exec_error_errno(context
, params
, r
, "Failed to apply SUID/SGID restrictions: %m");
5121 r
= apply_restrict_namespaces(context
, params
);
5123 *exit_status
= EXIT_SECCOMP
;
5124 return log_exec_error_errno(context
, params
, r
, "Failed to apply namespace restrictions: %m");
5127 r
= apply_protect_sysctl(context
, params
);
5129 *exit_status
= EXIT_SECCOMP
;
5130 return log_exec_error_errno(context
, params
, r
, "Failed to apply sysctl restrictions: %m");
5133 r
= apply_protect_kernel_modules(context
, params
);
5135 *exit_status
= EXIT_SECCOMP
;
5136 return log_exec_error_errno(context
, params
, r
, "Failed to apply module loading restrictions: %m");
5139 r
= apply_protect_kernel_logs(context
, params
);
5141 *exit_status
= EXIT_SECCOMP
;
5142 return log_exec_error_errno(context
, params
, r
, "Failed to apply kernel log restrictions: %m");
5145 r
= apply_protect_clock(context
, params
);
5147 *exit_status
= EXIT_SECCOMP
;
5148 return log_exec_error_errno(context
, params
, r
, "Failed to apply clock restrictions: %m");
5151 r
= apply_private_devices(context
, params
);
5153 *exit_status
= EXIT_SECCOMP
;
5154 return log_exec_error_errno(context
, params
, r
, "Failed to set up private devices: %m");
5157 r
= apply_syscall_archs(context
, params
);
5159 *exit_status
= EXIT_SECCOMP
;
5160 return log_exec_error_errno(context
, params
, r
, "Failed to apply syscall architecture restrictions: %m");
5163 r
= apply_lock_personality(context
, params
);
5165 *exit_status
= EXIT_SECCOMP
;
5166 return log_exec_error_errno(context
, params
, r
, "Failed to lock personalities: %m");
5169 r
= apply_syscall_log(context
, params
);
5171 *exit_status
= EXIT_SECCOMP
;
5172 return log_exec_error_errno(context
, params
, r
, "Failed to apply system call log filters: %m");
5177 r
= apply_restrict_filesystems(context
, params
);
5179 *exit_status
= EXIT_BPF
;
5180 return log_exec_error_errno(context
, params
, r
, "Failed to restrict filesystems: %m");
5185 /* This really should remain as close to the execve() as possible, to make sure our own code is affected
5186 * by the filter as little as possible. */
5187 r
= apply_syscall_filter(context
, params
, needs_ambient_hack
);
5189 *exit_status
= EXIT_SECCOMP
;
5190 return log_exec_error_errno(context
, params
, r
, "Failed to apply system call filters: %m");
5193 if (keep_seccomp_privileges
) {
5194 /* Restore the capability bounding set with what's expected from the service + the
5195 * ambient capabilities hack */
5196 if (!cap_test_all(saved_bset
)) {
5197 r
= capability_bounding_set_drop(saved_bset
, /* right_now= */ false);
5199 *exit_status
= EXIT_CAPABILITIES
;
5200 return log_exec_error_errno(context
, params
, r
, "Failed to drop bset capabilities: %m");
5204 /* Only drop CAP_SYS_ADMIN if it's not in the bounding set, otherwise we'll break
5205 * applications that use it. */
5206 if (!FLAGS_SET(saved_bset
, (UINT64_C(1) << CAP_SYS_ADMIN
))) {
5207 r
= drop_capability(CAP_SYS_ADMIN
);
5209 *exit_status
= EXIT_USER
;
5210 return log_exec_error_errno(context
, params
, r
, "Failed to drop CAP_SYS_ADMIN: %m");
5214 /* Only drop CAP_SETPCAP if it's not in the bounding set, otherwise we'll break
5215 * applications that use it. */
5216 if (!FLAGS_SET(saved_bset
, (UINT64_C(1) << CAP_SETPCAP
))) {
5217 r
= drop_capability(CAP_SETPCAP
);
5219 *exit_status
= EXIT_USER
;
5220 return log_exec_error_errno(context
, params
, r
, "Failed to drop CAP_SETPCAP: %m");
5224 if (prctl(PR_SET_KEEPCAPS
, 0) < 0) {
5225 *exit_status
= EXIT_USER
;
5226 return log_exec_error_errno(context
, params
, errno
, "Failed to drop keep capabilities flag: %m");
5233 if (!strv_isempty(context
->unset_environment
)) {
5236 ee
= strv_env_delete(accum_env
, 1, context
->unset_environment
);
5238 *exit_status
= EXIT_MEMORY
;
5242 strv_free_and_replace(accum_env
, ee
);
5245 if (!FLAGS_SET(command
->flags
, EXEC_COMMAND_NO_ENV_EXPAND
)) {
5246 _cleanup_strv_free_
char **unset_variables
= NULL
, **bad_variables
= NULL
;
5248 r
= replace_env_argv(command
->argv
, accum_env
, &replaced_argv
, &unset_variables
, &bad_variables
);
5250 *exit_status
= EXIT_MEMORY
;
5251 return log_exec_error_errno(context
,
5254 "Failed to replace environment variables: %m");
5256 final_argv
= replaced_argv
;
5258 if (!strv_isempty(unset_variables
)) {
5259 _cleanup_free_
char *ju
= strv_join(unset_variables
, ", ");
5260 log_exec_warning(context
,
5262 "Referenced but unset environment variable evaluates to an empty string: %s",
5266 if (!strv_isempty(bad_variables
)) {
5267 _cleanup_free_
char *jb
= strv_join(bad_variables
, ", ");
5268 log_exec_warning(context
,
5270 "Invalid environment variable name evaluates to an empty string: %s",
5274 final_argv
= command
->argv
;
5276 log_command_line(context
, params
, "Executing", executable
, final_argv
);
5278 if (params
->exec_fd
>= 0) {
5281 /* We have finished with all our initializations. Let's now let the manager know that. From this point
5282 * on, if the manager sees POLLHUP on the exec_fd, then execve() was successful. */
5284 if (write(params
->exec_fd
, &hot
, sizeof(hot
)) < 0) {
5285 *exit_status
= EXIT_EXEC
;
5286 return log_exec_error_errno(context
, params
, errno
, "Failed to enable exec_fd: %m");
5290 r
= fexecve_or_execve(executable_fd
, executable
, final_argv
, accum_env
);
5292 if (params
->exec_fd
>= 0) {
5295 /* The execve() failed. This means the exec_fd is still open. Which means we need to tell the manager
5296 * that POLLHUP on it no longer means execve() succeeded. */
5298 if (write(params
->exec_fd
, &hot
, sizeof(hot
)) < 0) {
5299 *exit_status
= EXIT_EXEC
;
5300 return log_exec_error_errno(context
, params
, errno
, "Failed to disable exec_fd: %m");
5304 *exit_status
= EXIT_EXEC
;
5305 return log_exec_error_errno(context
, params
, r
, "Failed to execute %s: %m", executable
);