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execute: fix terminal chowning logic
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1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
2
3 /***
4 This file is part of systemd.
5
6 Copyright 2010 Lennart Poettering
7
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
20 ***/
21
22 #include <assert.h>
23 #include <dirent.h>
24 #include <errno.h>
25 #include <fcntl.h>
26 #include <unistd.h>
27 #include <string.h>
28 #include <signal.h>
29 #include <sys/socket.h>
30 #include <sys/un.h>
31 #include <sys/prctl.h>
32 #include <linux/sched.h>
33 #include <sys/types.h>
34 #include <sys/stat.h>
35 #include <grp.h>
36 #include <pwd.h>
37
38 #include "execute.h"
39 #include "strv.h"
40 #include "macro.h"
41 #include "util.h"
42 #include "log.h"
43 #include "ioprio.h"
44 #include "securebits.h"
45 #include "cgroup.h"
46
47 /* This assumes there is a 'tty' group */
48 #define TTY_MODE 0620
49
50 static int shift_fds(int fds[], unsigned n_fds) {
51 int start, restart_from;
52
53 if (n_fds <= 0)
54 return 0;
55
56 /* Modifies the fds array! (sorts it) */
57
58 assert(fds);
59
60 start = 0;
61 for (;;) {
62 int i;
63
64 restart_from = -1;
65
66 for (i = start; i < (int) n_fds; i++) {
67 int nfd;
68
69 /* Already at right index? */
70 if (fds[i] == i+3)
71 continue;
72
73 if ((nfd = fcntl(fds[i], F_DUPFD, i+3)) < 0)
74 return -errno;
75
76 close_nointr_nofail(fds[i]);
77 fds[i] = nfd;
78
79 /* Hmm, the fd we wanted isn't free? Then
80 * let's remember that and try again from here*/
81 if (nfd != i+3 && restart_from < 0)
82 restart_from = i;
83 }
84
85 if (restart_from < 0)
86 break;
87
88 start = restart_from;
89 }
90
91 return 0;
92 }
93
94 static int flags_fds(const int fds[], unsigned n_fds, bool nonblock) {
95 unsigned i;
96 int r;
97
98 if (n_fds <= 0)
99 return 0;
100
101 assert(fds);
102
103 /* Drops/Sets O_NONBLOCK and FD_CLOEXEC from the file flags */
104
105 for (i = 0; i < n_fds; i++) {
106
107 if ((r = fd_nonblock(fds[i], nonblock)) < 0)
108 return r;
109
110 /* We unconditionally drop FD_CLOEXEC from the fds,
111 * since after all we want to pass these fds to our
112 * children */
113
114 if ((r = fd_cloexec(fds[i], false)) < 0)
115 return r;
116 }
117
118 return 0;
119 }
120
121 static const char *tty_path(const ExecContext *context) {
122 assert(context);
123
124 if (context->tty_path)
125 return context->tty_path;
126
127 return "/dev/console";
128 }
129
130 static int open_null_as(int flags, int nfd) {
131 int fd, r;
132
133 assert(nfd >= 0);
134
135 if ((fd = open("/dev/null", flags|O_NOCTTY)) < 0)
136 return -errno;
137
138 if (fd != nfd) {
139 r = dup2(fd, nfd) < 0 ? -errno : nfd;
140 close_nointr_nofail(fd);
141 } else
142 r = nfd;
143
144 return r;
145 }
146
147 static int connect_logger_as(const ExecContext *context, ExecOutput output, const char *ident, int nfd) {
148 int fd, r;
149 union {
150 struct sockaddr sa;
151 struct sockaddr_un un;
152 } sa;
153
154 assert(context);
155 assert(output < _EXEC_OUTPUT_MAX);
156 assert(ident);
157 assert(nfd >= 0);
158
159 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
160 return -errno;
161
162 zero(sa);
163 sa.sa.sa_family = AF_UNIX;
164 strncpy(sa.un.sun_path+1, LOGGER_SOCKET, sizeof(sa.un.sun_path)-1);
165
166 if (connect(fd, &sa.sa, sizeof(sa)) < 0) {
167 close_nointr_nofail(fd);
168 return -errno;
169 }
170
171 if (shutdown(fd, SHUT_RD) < 0) {
172 close_nointr_nofail(fd);
173 return -errno;
174 }
175
176 /* We speak a very simple protocol between log server
177 * and client: one line for the log destination (kmsg
178 * or syslog), followed by the priority field,
179 * followed by the process name. Since we replaced
180 * stdin/stderr we simple use stdio to write to
181 * it. Note that we use stderr, to minimize buffer
182 * flushing issues. */
183
184 dprintf(fd,
185 "%s\n"
186 "%i\n"
187 "%s\n",
188 output == EXEC_OUTPUT_KERNEL ? "kmsg" : "syslog",
189 context->syslog_priority,
190 context->syslog_identifier ? context->syslog_identifier : ident);
191
192 if (fd != nfd) {
193 r = dup2(fd, nfd) < 0 ? -errno : nfd;
194 close_nointr_nofail(fd);
195 } else
196 r = nfd;
197
198 return r;
199 }
200 static int open_terminal_as(const char *path, mode_t mode, int nfd) {
201 int fd, r;
202
203 assert(path);
204 assert(nfd >= 0);
205
206 if ((fd = open_terminal(path, mode | O_NOCTTY)) < 0)
207 return fd;
208
209 if (fd != nfd) {
210 r = dup2(fd, nfd) < 0 ? -errno : nfd;
211 close_nointr_nofail(fd);
212 } else
213 r = nfd;
214
215 return r;
216 }
217
218 static bool is_terminal_input(ExecInput i) {
219 return
220 i == EXEC_INPUT_TTY ||
221 i == EXEC_INPUT_TTY_FORCE ||
222 i == EXEC_INPUT_TTY_FAIL;
223 }
224
225 static int setup_input(const ExecContext *context) {
226 assert(context);
227
228 switch (context->std_input) {
229
230 case EXEC_INPUT_NULL:
231 return open_null_as(O_RDONLY, STDIN_FILENO);
232
233 case EXEC_INPUT_TTY:
234 case EXEC_INPUT_TTY_FORCE:
235 case EXEC_INPUT_TTY_FAIL: {
236 int fd, r;
237
238 if ((fd = acquire_terminal(
239 tty_path(context),
240 context->std_input == EXEC_INPUT_TTY_FAIL,
241 context->std_input == EXEC_INPUT_TTY_FORCE)) < 0)
242 return fd;
243
244 if (fd != STDIN_FILENO) {
245 r = dup2(fd, STDIN_FILENO) < 0 ? -errno : STDIN_FILENO;
246 close_nointr_nofail(fd);
247 } else
248 r = STDIN_FILENO;
249
250 return r;
251 }
252
253 default:
254 assert_not_reached("Unknown input type");
255 }
256 }
257
258 static int setup_output(const ExecContext *context, const char *ident) {
259 assert(context);
260 assert(ident);
261
262 /* This expects the input is already set up */
263
264 switch (context->std_output) {
265
266 case EXEC_OUTPUT_INHERIT:
267
268 /* If the input is connected to a terminal, inherit that... */
269 if (is_terminal_input(context->std_input))
270 return dup2(STDIN_FILENO, STDOUT_FILENO) < 0 ? -errno : STDOUT_FILENO;
271
272 return 0;
273
274 case EXEC_OUTPUT_NULL:
275 return open_null_as(O_WRONLY, STDOUT_FILENO);
276
277 case EXEC_OUTPUT_TTY: {
278 if (is_terminal_input(context->std_input))
279 return dup2(STDIN_FILENO, STDOUT_FILENO) < 0 ? -errno : STDOUT_FILENO;
280
281 /* We don't reset the terminal if this is just about output */
282 return open_terminal_as(tty_path(context), O_WRONLY, STDOUT_FILENO);
283 }
284
285 case EXEC_OUTPUT_SYSLOG:
286 case EXEC_OUTPUT_KERNEL:
287 return connect_logger_as(context, context->std_output, ident, STDOUT_FILENO);
288
289 default:
290 assert_not_reached("Unknown output type");
291 }
292 }
293
294 static int setup_error(const ExecContext *context, const char *ident) {
295 assert(context);
296 assert(ident);
297
298 /* This expects the input and output are already set up */
299
300 /* Don't change the stderr file descriptor if we inherit all
301 * the way and are not on a tty */
302 if (context->std_error == EXEC_OUTPUT_INHERIT &&
303 context->std_output == EXEC_OUTPUT_INHERIT &&
304 !is_terminal_input(context->std_input))
305 return STDERR_FILENO;
306
307 /* Duplicate form stdout if possible */
308 if (context->std_error == context->std_output ||
309 context->std_error == EXEC_OUTPUT_INHERIT)
310 return dup2(STDOUT_FILENO, STDERR_FILENO) < 0 ? -errno : STDERR_FILENO;
311
312 switch (context->std_error) {
313
314 case EXEC_OUTPUT_NULL:
315 return open_null_as(O_WRONLY, STDERR_FILENO);
316
317 case EXEC_OUTPUT_TTY:
318 if (is_terminal_input(context->std_input))
319 return dup2(STDIN_FILENO, STDERR_FILENO) < 0 ? -errno : STDERR_FILENO;
320
321 /* We don't reset the terminal if this is just about output */
322 return open_terminal_as(tty_path(context), O_WRONLY, STDERR_FILENO);
323
324 case EXEC_OUTPUT_SYSLOG:
325 case EXEC_OUTPUT_KERNEL:
326 return connect_logger_as(context, context->std_error, ident, STDERR_FILENO);
327
328 default:
329 assert_not_reached("Unknown error type");
330 }
331 }
332
333 static int chown_terminal(int fd, uid_t uid) {
334 struct stat st;
335
336 assert(fd >= 0);
337
338 /* This might fail. What matters are the results. */
339 fchown(fd, uid, -1);
340 fchmod(fd, TTY_MODE);
341
342 if (fstat(fd, &st) < 0)
343 return -errno;
344
345 if (st.st_uid != uid || (st.st_mode & 0777) != TTY_MODE)
346 return -EPERM;
347
348 return 0;
349 }
350
351 static int setup_confirm_stdio(const ExecContext *context,
352 int *_saved_stdin,
353 int *_saved_stdout) {
354 int fd = -1, saved_stdin, saved_stdout = -1, r;
355
356 assert(context);
357 assert(_saved_stdin);
358 assert(_saved_stdout);
359
360 /* This returns positive EXIT_xxx return values instead of
361 * negative errno style values! */
362
363 if ((saved_stdin = fcntl(STDIN_FILENO, F_DUPFD, 3)) < 0)
364 return EXIT_STDIN;
365
366 if ((saved_stdout = fcntl(STDOUT_FILENO, F_DUPFD, 3)) < 0) {
367 r = EXIT_STDOUT;
368 goto fail;
369 }
370
371 if ((fd = acquire_terminal(
372 tty_path(context),
373 context->std_input == EXEC_INPUT_TTY_FAIL,
374 context->std_input == EXEC_INPUT_TTY_FORCE)) < 0) {
375 r = EXIT_STDIN;
376 goto fail;
377 }
378
379 if (chown_terminal(fd, getuid()) < 0) {
380 r = EXIT_STDIN;
381 goto fail;
382 }
383
384 if (dup2(fd, STDIN_FILENO) < 0) {
385 r = EXIT_STDIN;
386 goto fail;
387 }
388
389 if (dup2(fd, STDOUT_FILENO) < 0) {
390 r = EXIT_STDOUT;
391 goto fail;
392 }
393
394 if (fd >= 2)
395 close_nointr_nofail(fd);
396
397 *_saved_stdin = saved_stdin;
398 *_saved_stdout = saved_stdout;
399
400 return 0;
401
402 fail:
403 if (saved_stdout >= 0)
404 close_nointr_nofail(saved_stdout);
405
406 if (saved_stdin >= 0)
407 close_nointr_nofail(saved_stdin);
408
409 if (fd >= 0)
410 close_nointr_nofail(fd);
411
412 return r;
413 }
414
415 static int restore_conform_stdio(const ExecContext *context,
416 int *saved_stdin,
417 int *saved_stdout,
418 bool *keep_stdin,
419 bool *keep_stdout) {
420
421 assert(context);
422 assert(saved_stdin);
423 assert(*saved_stdin >= 0);
424 assert(saved_stdout);
425 assert(*saved_stdout >= 0);
426
427 /* This returns positive EXIT_xxx return values instead of
428 * negative errno style values! */
429
430 if (is_terminal_input(context->std_input)) {
431
432 /* The service wants terminal input. */
433
434 *keep_stdin = true;
435 *keep_stdout =
436 context->std_output == EXEC_OUTPUT_INHERIT ||
437 context->std_output == EXEC_OUTPUT_TTY;
438
439 } else {
440 /* If the service doesn't want a controlling terminal,
441 * then we need to get rid entirely of what we have
442 * already. */
443
444 if (release_terminal() < 0)
445 return EXIT_STDIN;
446
447 if (dup2(*saved_stdin, STDIN_FILENO) < 0)
448 return EXIT_STDIN;
449
450 if (dup2(*saved_stdout, STDOUT_FILENO) < 0)
451 return EXIT_STDOUT;
452
453 *keep_stdout = *keep_stdin = false;
454 }
455
456 return 0;
457 }
458
459 static int get_group_creds(const char *groupname, gid_t *gid) {
460 struct group *g;
461 unsigned long lu;
462
463 assert(groupname);
464 assert(gid);
465
466 /* We enforce some special rules for gid=0: in order to avoid
467 * NSS lookups for root we hardcode its data. */
468
469 if (streq(groupname, "root") || streq(groupname, "0")) {
470 *gid = 0;
471 return 0;
472 }
473
474 if (safe_atolu(groupname, &lu) >= 0) {
475 errno = 0;
476 g = getgrgid((gid_t) lu);
477 } else {
478 errno = 0;
479 g = getgrnam(groupname);
480 }
481
482 if (!g)
483 return errno != 0 ? -errno : -ESRCH;
484
485 *gid = g->gr_gid;
486 return 0;
487 }
488
489 static int get_user_creds(const char **username, uid_t *uid, gid_t *gid, const char **home) {
490 struct passwd *p;
491 unsigned long lu;
492
493 assert(username);
494 assert(*username);
495 assert(uid);
496 assert(gid);
497 assert(home);
498
499 /* We enforce some special rules for uid=0: in order to avoid
500 * NSS lookups for root we hardcode its data. */
501
502 if (streq(*username, "root") || streq(*username, "0")) {
503 *username = "root";
504 *uid = 0;
505 *gid = 0;
506 *home = "/root";
507 return 0;
508 }
509
510 if (safe_atolu(*username, &lu) >= 0) {
511 errno = 0;
512 p = getpwuid((uid_t) lu);
513
514 /* If there are multiple users with the same id, make
515 * sure to leave $USER to the configured value instead
516 * of the first occurence in the database. However if
517 * the uid was configured by a numeric uid, then let's
518 * pick the real username from /etc/passwd. */
519 if (*username && p)
520 *username = p->pw_name;
521 } else {
522 errno = 0;
523 p = getpwnam(*username);
524 }
525
526 if (!p)
527 return errno != 0 ? -errno : -ESRCH;
528
529 *uid = p->pw_uid;
530 *gid = p->pw_gid;
531 *home = p->pw_dir;
532 return 0;
533 }
534
535 static int enforce_groups(const ExecContext *context, const char *username, gid_t gid) {
536 bool keep_groups = false;
537 int r;
538
539 assert(context);
540
541 /* Lookup and ser GID and supplementary group list. Here too
542 * we avoid NSS lookups for gid=0. */
543
544 if (context->group || username) {
545
546 if (context->group)
547 if ((r = get_group_creds(context->group, &gid)) < 0)
548 return r;
549
550 /* First step, initialize groups from /etc/groups */
551 if (username && gid != 0) {
552 if (initgroups(username, gid) < 0)
553 return -errno;
554
555 keep_groups = true;
556 }
557
558 /* Second step, set our gids */
559 if (setresgid(gid, gid, gid) < 0)
560 return -errno;
561 }
562
563 if (context->supplementary_groups) {
564 int ngroups_max, k;
565 gid_t *gids;
566 char **i;
567
568 /* Final step, initialize any manually set supplementary groups */
569 ngroups_max = (int) sysconf(_SC_NGROUPS_MAX);
570
571 if (!(gids = new(gid_t, ngroups_max)))
572 return -ENOMEM;
573
574 if (keep_groups) {
575 if ((k = getgroups(ngroups_max, gids)) < 0) {
576 free(gids);
577 return -errno;
578 }
579 } else
580 k = 0;
581
582 STRV_FOREACH(i, context->supplementary_groups) {
583
584 if (k >= ngroups_max) {
585 free(gids);
586 return -E2BIG;
587 }
588
589 if ((r = get_group_creds(*i, gids+k)) < 0) {
590 free(gids);
591 return r;
592 }
593
594 k++;
595 }
596
597 if (setgroups(k, gids) < 0) {
598 free(gids);
599 return -errno;
600 }
601
602 free(gids);
603 }
604
605 return 0;
606 }
607
608 static int enforce_user(const ExecContext *context, uid_t uid) {
609 int r;
610 assert(context);
611
612 /* Sets (but doesn't lookup) the uid and make sure we keep the
613 * capabilities while doing so. */
614
615 if (context->capabilities) {
616 cap_t d;
617 static const cap_value_t bits[] = {
618 CAP_SETUID, /* Necessary so that we can run setresuid() below */
619 CAP_SETPCAP /* Necessary so that we can set PR_SET_SECUREBITS later on */
620 };
621
622 /* First step: If we need to keep capabilities but
623 * drop privileges we need to make sure we keep our
624 * caps, whiel we drop priviliges. */
625 if (uid != 0) {
626 int sb = context->secure_bits|SECURE_KEEP_CAPS;
627
628 if (prctl(PR_GET_SECUREBITS) != sb)
629 if (prctl(PR_SET_SECUREBITS, sb) < 0)
630 return -errno;
631 }
632
633 /* Second step: set the capabilites. This will reduce
634 * the capabilities to the minimum we need. */
635
636 if (!(d = cap_dup(context->capabilities)))
637 return -errno;
638
639 if (cap_set_flag(d, CAP_EFFECTIVE, ELEMENTSOF(bits), bits, CAP_SET) < 0 ||
640 cap_set_flag(d, CAP_PERMITTED, ELEMENTSOF(bits), bits, CAP_SET) < 0) {
641 r = -errno;
642 cap_free(d);
643 return r;
644 }
645
646 if (cap_set_proc(d) < 0) {
647 r = -errno;
648 cap_free(d);
649 return r;
650 }
651
652 cap_free(d);
653 }
654
655 /* Third step: actually set the uids */
656 if (setresuid(uid, uid, uid) < 0)
657 return -errno;
658
659 /* At this point we should have all necessary capabilities but
660 are otherwise a normal user. However, the caps might got
661 corrupted due to the setresuid() so we need clean them up
662 later. This is done outside of this call. */
663
664 return 0;
665 }
666
667 int exec_spawn(ExecCommand *command,
668 const ExecContext *context,
669 int fds[], unsigned n_fds,
670 bool apply_permissions,
671 bool apply_chroot,
672 bool confirm_spawn,
673 CGroupBonding *cgroup_bondings,
674 pid_t *ret) {
675
676 pid_t pid;
677 int r;
678 char *line;
679
680 assert(command);
681 assert(context);
682 assert(ret);
683 assert(fds || n_fds <= 0);
684
685 if (!(line = exec_command_line(command)))
686 return -ENOMEM;
687
688 log_debug("About to execute: %s", line);
689 free(line);
690
691 if (cgroup_bondings)
692 if ((r = cgroup_bonding_realize_list(cgroup_bondings)))
693 return r;
694
695 if ((pid = fork()) < 0)
696 return -errno;
697
698 if (pid == 0) {
699 int i;
700 sigset_t ss;
701 const char *username = NULL, *home = NULL;
702 uid_t uid = (uid_t) -1;
703 gid_t gid = (gid_t) -1;
704 char **our_env = NULL, **final_env = NULL;
705 unsigned n_env = 0;
706 int saved_stdout = -1, saved_stdin = -1;
707 bool keep_stdout = false, keep_stdin = false;
708
709 /* child */
710
711 reset_all_signal_handlers();
712
713 if (sigemptyset(&ss) < 0 ||
714 sigprocmask(SIG_SETMASK, &ss, NULL) < 0) {
715 r = EXIT_SIGNAL_MASK;
716 goto fail;
717 }
718
719 if (setsid() < 0) {
720 r = EXIT_SETSID;
721 goto fail;
722 }
723
724 umask(context->umask);
725
726 if (confirm_spawn) {
727 char response;
728
729 /* Set up terminal for the question */
730 if ((r = setup_confirm_stdio(context,
731 &saved_stdin, &saved_stdout)))
732 goto fail;
733
734 /* Now ask the question. */
735 if (!(line = exec_command_line(command))) {
736 r = EXIT_MEMORY;
737 goto fail;
738 }
739
740 r = ask(&response, "yns", "Execute %s? [Yes, No, Skip] ", line);
741 free(line);
742
743 if (r < 0 || response == 'n') {
744 r = EXIT_CONFIRM;
745 goto fail;
746 } else if (response == 's') {
747 r = 0;
748 goto fail;
749 }
750
751 /* Release terminal for the question */
752 if ((r = restore_conform_stdio(context,
753 &saved_stdin, &saved_stdout,
754 &keep_stdin, &keep_stdout)))
755 goto fail;
756 }
757
758 if (!keep_stdin)
759 if (setup_input(context) < 0) {
760 r = EXIT_STDIN;
761 goto fail;
762 }
763
764 if (!keep_stdout)
765 if (setup_output(context, file_name_from_path(command->path)) < 0) {
766 r = EXIT_STDOUT;
767 goto fail;
768 }
769
770 if (setup_error(context, file_name_from_path(command->path)) < 0) {
771 r = EXIT_STDERR;
772 goto fail;
773 }
774
775 if (cgroup_bondings)
776 if ((r = cgroup_bonding_install_list(cgroup_bondings, 0)) < 0) {
777 r = EXIT_CGROUP;
778 goto fail;
779 }
780
781 if (context->oom_adjust_set) {
782 char t[16];
783
784 snprintf(t, sizeof(t), "%i", context->oom_adjust);
785 char_array_0(t);
786
787 if (write_one_line_file("/proc/self/oom_adj", t) < 0) {
788 r = EXIT_OOM_ADJUST;
789 goto fail;
790 }
791 }
792
793 if (context->nice_set)
794 if (setpriority(PRIO_PROCESS, 0, context->nice) < 0) {
795 r = EXIT_NICE;
796 goto fail;
797 }
798
799 if (context->cpu_sched_set) {
800 struct sched_param param;
801
802 zero(param);
803 param.sched_priority = context->cpu_sched_priority;
804
805 if (sched_setscheduler(0, context->cpu_sched_policy |
806 (context->cpu_sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0), &param) < 0) {
807 r = EXIT_SETSCHEDULER;
808 goto fail;
809 }
810 }
811
812 if (context->cpu_affinity_set)
813 if (sched_setaffinity(0, sizeof(context->cpu_affinity), &context->cpu_affinity) < 0) {
814 r = EXIT_CPUAFFINITY;
815 goto fail;
816 }
817
818 if (context->ioprio_set)
819 if (ioprio_set(IOPRIO_WHO_PROCESS, 0, context->ioprio) < 0) {
820 r = EXIT_IOPRIO;
821 goto fail;
822 }
823
824 if (context->timer_slack_ns_set)
825 if (prctl(PR_SET_TIMERSLACK, context->timer_slack_ns_set) < 0) {
826 r = EXIT_TIMERSLACK;
827 goto fail;
828 }
829
830 if (context->user) {
831 username = context->user;
832 if (get_user_creds(&username, &uid, &gid, &home) < 0) {
833 r = EXIT_USER;
834 goto fail;
835 }
836
837 if (is_terminal_input(context->std_input))
838 if (chown_terminal(STDIN_FILENO, uid) < 0) {
839 r = EXIT_STDIN;
840 goto fail;
841 }
842 }
843
844 if (apply_permissions)
845 if (enforce_groups(context, username, uid) < 0) {
846 r = EXIT_GROUP;
847 goto fail;
848 }
849
850 if (apply_chroot) {
851 if (context->root_directory)
852 if (chroot(context->root_directory) < 0) {
853 r = EXIT_CHROOT;
854 goto fail;
855 }
856
857 if (chdir(context->working_directory ? context->working_directory : "/") < 0) {
858 r = EXIT_CHDIR;
859 goto fail;
860 }
861 } else {
862
863 char *d;
864
865 if (asprintf(&d, "%s/%s",
866 context->root_directory ? context->root_directory : "",
867 context->working_directory ? context->working_directory : "") < 0) {
868 r = EXIT_MEMORY;
869 goto fail;
870 }
871
872 if (chdir(d) < 0) {
873 free(d);
874 r = EXIT_CHDIR;
875 goto fail;
876 }
877
878 free(d);
879 }
880
881 if (close_all_fds(fds, n_fds) < 0 ||
882 shift_fds(fds, n_fds) < 0 ||
883 flags_fds(fds, n_fds, context->non_blocking) < 0) {
884 r = EXIT_FDS;
885 goto fail;
886 }
887
888 if (apply_permissions) {
889
890 for (i = 0; i < RLIMIT_NLIMITS; i++) {
891 if (!context->rlimit[i])
892 continue;
893
894 if (setrlimit(i, context->rlimit[i]) < 0) {
895 r = EXIT_LIMITS;
896 goto fail;
897 }
898 }
899
900 if (context->user)
901 if (enforce_user(context, uid) < 0) {
902 r = EXIT_USER;
903 goto fail;
904 }
905
906 /* PR_GET_SECUREBITS is not priviliged, while
907 * PR_SET_SECUREBITS is. So to suppress
908 * potential EPERMs we'll try not to call
909 * PR_SET_SECUREBITS unless necessary. */
910 if (prctl(PR_GET_SECUREBITS) != context->secure_bits)
911 if (prctl(PR_SET_SECUREBITS, context->secure_bits) < 0) {
912 r = EXIT_SECUREBITS;
913 goto fail;
914 }
915
916 if (context->capabilities)
917 if (cap_set_proc(context->capabilities) < 0) {
918 r = EXIT_CAPABILITIES;
919 goto fail;
920 }
921 }
922
923 if (!(our_env = new0(char*, 6))) {
924 r = EXIT_MEMORY;
925 goto fail;
926 }
927
928 if (n_fds > 0)
929 if (asprintf(our_env + n_env++, "LISTEN_PID=%llu", (unsigned long long) getpid()) < 0 ||
930 asprintf(our_env + n_env++, "LISTEN_FDS=%u", n_fds) < 0) {
931 r = EXIT_MEMORY;
932 goto fail;
933 }
934
935 if (home)
936 if (asprintf(our_env + n_env++, "HOME=%s", home) < 0) {
937 r = EXIT_MEMORY;
938 goto fail;
939 }
940
941 if (username)
942 if (asprintf(our_env + n_env++, "LOGNAME=%s", username) < 0 ||
943 asprintf(our_env + n_env++, "USER=%s", username) < 0) {
944 r = EXIT_MEMORY;
945 goto fail;
946 }
947
948 if (!(final_env = strv_env_merge(environ, our_env, context->environment, NULL))) {
949 r = EXIT_MEMORY;
950 goto fail;
951 }
952
953 execve(command->path, command->argv, final_env);
954 r = EXIT_EXEC;
955
956 fail:
957 strv_free(our_env);
958 strv_free(final_env);
959
960 if (saved_stdin >= 0)
961 close_nointr_nofail(saved_stdin);
962
963 if (saved_stdout >= 0)
964 close_nointr_nofail(saved_stdout);
965
966 _exit(r);
967 }
968
969 /* We add the new process to the cgroup both in the child (so
970 * that we can be sure that no user code is ever executed
971 * outside of the cgroup) and in the parent (so that we can be
972 * sure that when we kill the cgroup the process will be
973 * killed too). */
974 if (cgroup_bondings)
975 if ((r = cgroup_bonding_install_list(cgroup_bondings, pid)) < 0) {
976 r = EXIT_CGROUP;
977 goto fail;
978 }
979
980 log_debug("Forked %s as %llu", command->path, (unsigned long long) pid);
981
982 command->exec_status.pid = pid;
983 command->exec_status.start_timestamp = now(CLOCK_REALTIME);
984
985 *ret = pid;
986 return 0;
987 }
988
989 void exec_context_init(ExecContext *c) {
990 assert(c);
991
992 c->umask = 0002;
993 c->oom_adjust = 0;
994 c->oom_adjust_set = false;
995 c->nice = 0;
996 c->nice_set = false;
997 c->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 0);
998 c->ioprio_set = false;
999 c->cpu_sched_policy = SCHED_OTHER;
1000 c->cpu_sched_priority = 0;
1001 c->cpu_sched_set = false;
1002 CPU_ZERO(&c->cpu_affinity);
1003 c->cpu_affinity_set = false;
1004 c->timer_slack_ns = 0;
1005 c->timer_slack_ns_set = false;
1006
1007 c->cpu_sched_reset_on_fork = false;
1008 c->non_blocking = false;
1009
1010 c->std_input = 0;
1011 c->std_output = 0;
1012 c->std_error = 0;
1013 c->syslog_priority = LOG_DAEMON|LOG_INFO;
1014
1015 c->secure_bits = 0;
1016 c->capability_bounding_set_drop = 0;
1017 }
1018
1019 void exec_context_done(ExecContext *c) {
1020 unsigned l;
1021
1022 assert(c);
1023
1024 strv_free(c->environment);
1025 c->environment = NULL;
1026
1027 for (l = 0; l < ELEMENTSOF(c->rlimit); l++) {
1028 free(c->rlimit[l]);
1029 c->rlimit[l] = NULL;
1030 }
1031
1032 free(c->working_directory);
1033 c->working_directory = NULL;
1034 free(c->root_directory);
1035 c->root_directory = NULL;
1036
1037 free(c->tty_path);
1038 c->tty_path = NULL;
1039
1040 free(c->syslog_identifier);
1041 c->syslog_identifier = NULL;
1042
1043 free(c->user);
1044 c->user = NULL;
1045
1046 free(c->group);
1047 c->group = NULL;
1048
1049 strv_free(c->supplementary_groups);
1050 c->supplementary_groups = NULL;
1051
1052 if (c->capabilities) {
1053 cap_free(c->capabilities);
1054 c->capabilities = NULL;
1055 }
1056 }
1057
1058 void exec_command_done(ExecCommand *c) {
1059 assert(c);
1060
1061 free(c->path);
1062 c->path = NULL;
1063
1064 strv_free(c->argv);
1065 c->argv = NULL;
1066 }
1067
1068 void exec_command_done_array(ExecCommand *c, unsigned n) {
1069 unsigned i;
1070
1071 for (i = 0; i < n; i++)
1072 exec_command_done(c+i);
1073 }
1074
1075 void exec_command_free_list(ExecCommand *c) {
1076 ExecCommand *i;
1077
1078 while ((i = c)) {
1079 LIST_REMOVE(ExecCommand, command, c, i);
1080 exec_command_done(i);
1081 free(i);
1082 }
1083 }
1084
1085 void exec_command_free_array(ExecCommand **c, unsigned n) {
1086 unsigned i;
1087
1088 for (i = 0; i < n; i++) {
1089 exec_command_free_list(c[i]);
1090 c[i] = NULL;
1091 }
1092 }
1093
1094 void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
1095 char ** e;
1096 unsigned i;
1097
1098 assert(c);
1099 assert(f);
1100
1101 if (!prefix)
1102 prefix = "";
1103
1104 fprintf(f,
1105 "%sUMask: %04o\n"
1106 "%sWorkingDirectory: %s\n"
1107 "%sRootDirectory: %s\n"
1108 "%sNonBlocking: %s\n",
1109 prefix, c->umask,
1110 prefix, c->working_directory ? c->working_directory : "/",
1111 prefix, c->root_directory ? c->root_directory : "/",
1112 prefix, yes_no(c->non_blocking));
1113
1114 if (c->environment)
1115 for (e = c->environment; *e; e++)
1116 fprintf(f, "%sEnvironment: %s\n", prefix, *e);
1117
1118 if (c->nice_set)
1119 fprintf(f,
1120 "%sNice: %i\n",
1121 prefix, c->nice);
1122
1123 if (c->oom_adjust_set)
1124 fprintf(f,
1125 "%sOOMAdjust: %i\n",
1126 prefix, c->oom_adjust);
1127
1128 for (i = 0; i < RLIM_NLIMITS; i++)
1129 if (c->rlimit[i])
1130 fprintf(f, "%s%s: %llu\n", prefix, rlimit_to_string(i), (unsigned long long) c->rlimit[i]->rlim_max);
1131
1132 if (c->ioprio_set)
1133 fprintf(f,
1134 "%sIOSchedulingClass: %s\n"
1135 "%sIOPriority: %i\n",
1136 prefix, ioprio_class_to_string(IOPRIO_PRIO_CLASS(c->ioprio)),
1137 prefix, (int) IOPRIO_PRIO_DATA(c->ioprio));
1138
1139 if (c->cpu_sched_set)
1140 fprintf(f,
1141 "%sCPUSchedulingPolicy: %s\n"
1142 "%sCPUSchedulingPriority: %i\n"
1143 "%sCPUSchedulingResetOnFork: %s\n",
1144 prefix, sched_policy_to_string(c->cpu_sched_policy),
1145 prefix, c->cpu_sched_priority,
1146 prefix, yes_no(c->cpu_sched_reset_on_fork));
1147
1148 if (c->cpu_affinity_set) {
1149 fprintf(f, "%sCPUAffinity:", prefix);
1150 for (i = 0; i < CPU_SETSIZE; i++)
1151 if (CPU_ISSET(i, &c->cpu_affinity))
1152 fprintf(f, " %i", i);
1153 fputs("\n", f);
1154 }
1155
1156 if (c->timer_slack_ns_set)
1157 fprintf(f, "%sTimerSlackNS: %lu\n", prefix, c->timer_slack_ns);
1158
1159 fprintf(f,
1160 "%sStandardInput: %s\n"
1161 "%sStandardOutput: %s\n"
1162 "%sStandardError: %s\n",
1163 prefix, exec_input_to_string(c->std_input),
1164 prefix, exec_output_to_string(c->std_output),
1165 prefix, exec_output_to_string(c->std_error));
1166
1167 if (c->tty_path)
1168 fprintf(f,
1169 "%sTTYPath: %s\n",
1170 prefix, c->tty_path);
1171
1172 if (c->std_output == EXEC_OUTPUT_SYSLOG || c->std_output == EXEC_OUTPUT_KERNEL ||
1173 c->std_error == EXEC_OUTPUT_SYSLOG || c->std_error == EXEC_OUTPUT_KERNEL)
1174 fprintf(f,
1175 "%sSyslogFacility: %s\n"
1176 "%sSyslogLevel: %s\n",
1177 prefix, log_facility_to_string(LOG_FAC(c->syslog_priority)),
1178 prefix, log_level_to_string(LOG_PRI(c->syslog_priority)));
1179
1180 if (c->capabilities) {
1181 char *t;
1182 if ((t = cap_to_text(c->capabilities, NULL))) {
1183 fprintf(f, "%sCapabilities: %s\n",
1184 prefix, t);
1185 cap_free(t);
1186 }
1187 }
1188
1189 if (c->secure_bits)
1190 fprintf(f, "%sSecure Bits:%s%s%s%s%s%s\n",
1191 prefix,
1192 (c->secure_bits & SECURE_KEEP_CAPS) ? " keep-caps" : "",
1193 (c->secure_bits & SECURE_KEEP_CAPS_LOCKED) ? " keep-caps-locked" : "",
1194 (c->secure_bits & SECURE_NO_SETUID_FIXUP) ? " no-setuid-fixup" : "",
1195 (c->secure_bits & SECURE_NO_SETUID_FIXUP_LOCKED) ? " no-setuid-fixup-locked" : "",
1196 (c->secure_bits & SECURE_NOROOT) ? " noroot" : "",
1197 (c->secure_bits & SECURE_NOROOT_LOCKED) ? "noroot-locked" : "");
1198
1199 if (c->capability_bounding_set_drop) {
1200 fprintf(f, "%sCapabilityBoundingSetDrop:", prefix);
1201
1202 for (i = 0; i <= CAP_LAST_CAP; i++)
1203 if (c->capability_bounding_set_drop & (1 << i)) {
1204 char *t;
1205
1206 if ((t = cap_to_name(i))) {
1207 fprintf(f, " %s", t);
1208 free(t);
1209 }
1210 }
1211
1212 fputs("\n", f);
1213 }
1214
1215 if (c->user)
1216 fprintf(f, "%sUser: %s", prefix, c->user);
1217 if (c->group)
1218 fprintf(f, "%sGroup: %s", prefix, c->group);
1219
1220 if (c->supplementary_groups) {
1221 char **g;
1222
1223 fprintf(f, "%sSupplementaryGroups:", prefix);
1224
1225 STRV_FOREACH(g, c->supplementary_groups)
1226 fprintf(f, " %s", *g);
1227
1228 fputs("\n", f);
1229 }
1230 }
1231
1232 void exec_status_fill(ExecStatus *s, pid_t pid, int code, int status) {
1233 assert(s);
1234
1235 s->pid = pid;
1236 s->exit_timestamp = now(CLOCK_REALTIME);
1237
1238 s->code = code;
1239 s->status = status;
1240 }
1241
1242 void exec_status_dump(ExecStatus *s, FILE *f, const char *prefix) {
1243 char buf[FORMAT_TIMESTAMP_MAX];
1244
1245 assert(s);
1246 assert(f);
1247
1248 if (!prefix)
1249 prefix = "";
1250
1251 if (s->pid <= 0)
1252 return;
1253
1254 fprintf(f,
1255 "%sPID: %llu\n",
1256 prefix, (unsigned long long) s->pid);
1257
1258 if (s->start_timestamp > 0)
1259 fprintf(f,
1260 "%sStart Timestamp: %s\n",
1261 prefix, format_timestamp(buf, sizeof(buf), s->start_timestamp));
1262
1263 if (s->exit_timestamp > 0)
1264 fprintf(f,
1265 "%sExit Timestamp: %s\n"
1266 "%sExit Code: %s\n"
1267 "%sExit Status: %i\n",
1268 prefix, format_timestamp(buf, sizeof(buf), s->exit_timestamp),
1269 prefix, sigchld_code_to_string(s->code),
1270 prefix, s->status);
1271 }
1272
1273 char *exec_command_line(ExecCommand *c) {
1274 size_t k;
1275 char *n, *p, **a;
1276 bool first = true;
1277
1278 assert(c);
1279 assert(c->argv);
1280
1281 k = 1;
1282 STRV_FOREACH(a, c->argv)
1283 k += strlen(*a)+3;
1284
1285 if (!(n = new(char, k)))
1286 return NULL;
1287
1288 p = n;
1289 STRV_FOREACH(a, c->argv) {
1290
1291 if (!first)
1292 *(p++) = ' ';
1293 else
1294 first = false;
1295
1296 if (strpbrk(*a, WHITESPACE)) {
1297 *(p++) = '\'';
1298 p = stpcpy(p, *a);
1299 *(p++) = '\'';
1300 } else
1301 p = stpcpy(p, *a);
1302
1303 }
1304
1305 *p = 0;
1306
1307 /* FIXME: this doesn't really handle arguments that have
1308 * spaces and ticks in them */
1309
1310 return n;
1311 }
1312
1313 void exec_command_dump(ExecCommand *c, FILE *f, const char *prefix) {
1314 char *p2;
1315 const char *prefix2;
1316
1317 char *cmd;
1318
1319 assert(c);
1320 assert(f);
1321
1322 if (!prefix)
1323 prefix = "";
1324 p2 = strappend(prefix, "\t");
1325 prefix2 = p2 ? p2 : prefix;
1326
1327 cmd = exec_command_line(c);
1328
1329 fprintf(f,
1330 "%sCommand Line: %s\n",
1331 prefix, cmd ? cmd : strerror(ENOMEM));
1332
1333 free(cmd);
1334
1335 exec_status_dump(&c->exec_status, f, prefix2);
1336
1337 free(p2);
1338 }
1339
1340 void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix) {
1341 assert(f);
1342
1343 if (!prefix)
1344 prefix = "";
1345
1346 LIST_FOREACH(command, c, c)
1347 exec_command_dump(c, f, prefix);
1348 }
1349
1350 void exec_command_append_list(ExecCommand **l, ExecCommand *e) {
1351 ExecCommand *end;
1352
1353 assert(l);
1354 assert(e);
1355
1356 if (*l) {
1357 /* It's kinda important that we keep the order here */
1358 LIST_FIND_TAIL(ExecCommand, command, *l, end);
1359 LIST_INSERT_AFTER(ExecCommand, command, *l, end, e);
1360 } else
1361 *l = e;
1362 }
1363
1364 int exec_command_set(ExecCommand *c, const char *path, ...) {
1365 va_list ap;
1366 char **l, *p;
1367
1368 assert(c);
1369 assert(path);
1370
1371 va_start(ap, path);
1372 l = strv_new_ap(path, ap);
1373 va_end(ap);
1374
1375 if (!l)
1376 return -ENOMEM;
1377
1378 if (!(p = strdup(path))) {
1379 strv_free(l);
1380 return -ENOMEM;
1381 }
1382
1383 free(c->path);
1384 c->path = p;
1385
1386 strv_free(c->argv);
1387 c->argv = l;
1388
1389 return 0;
1390 }
1391
1392 const char* exit_status_to_string(ExitStatus status) {
1393
1394 /* We cast to int here, so that -Wenum doesn't complain that
1395 * EXIT_SUCCESS/EXIT_FAILURE aren't in the enum */
1396
1397 switch ((int) status) {
1398
1399 case EXIT_SUCCESS:
1400 return "SUCCESS";
1401
1402 case EXIT_FAILURE:
1403 return "FAILURE";
1404
1405 case EXIT_INVALIDARGUMENT:
1406 return "INVALIDARGUMENT";
1407
1408 case EXIT_NOTIMPLEMENTED:
1409 return "NOTIMPLEMENTED";
1410
1411 case EXIT_NOPERMISSION:
1412 return "NOPERMISSION";
1413
1414 case EXIT_NOTINSTALLED:
1415 return "NOTINSSTALLED";
1416
1417 case EXIT_NOTCONFIGURED:
1418 return "NOTCONFIGURED";
1419
1420 case EXIT_NOTRUNNING:
1421 return "NOTRUNNING";
1422
1423 case EXIT_CHDIR:
1424 return "CHDIR";
1425
1426 case EXIT_NICE:
1427 return "NICE";
1428
1429 case EXIT_FDS:
1430 return "FDS";
1431
1432 case EXIT_EXEC:
1433 return "EXEC";
1434
1435 case EXIT_MEMORY:
1436 return "MEMORY";
1437
1438 case EXIT_LIMITS:
1439 return "LIMITS";
1440
1441 case EXIT_OOM_ADJUST:
1442 return "OOM_ADJUST";
1443
1444 case EXIT_SIGNAL_MASK:
1445 return "SIGNAL_MASK";
1446
1447 case EXIT_STDIN:
1448 return "STDIN";
1449
1450 case EXIT_STDOUT:
1451 return "STDOUT";
1452
1453 case EXIT_CHROOT:
1454 return "CHROOT";
1455
1456 case EXIT_IOPRIO:
1457 return "IOPRIO";
1458
1459 case EXIT_TIMERSLACK:
1460 return "TIMERSLACK";
1461
1462 case EXIT_SECUREBITS:
1463 return "SECUREBITS";
1464
1465 case EXIT_SETSCHEDULER:
1466 return "SETSCHEDULER";
1467
1468 case EXIT_CPUAFFINITY:
1469 return "CPUAFFINITY";
1470
1471 case EXIT_GROUP:
1472 return "GROUP";
1473
1474 case EXIT_USER:
1475 return "USER";
1476
1477 case EXIT_CAPABILITIES:
1478 return "CAPABILITIES";
1479
1480 case EXIT_CGROUP:
1481 return "CGROUP";
1482
1483 case EXIT_SETSID:
1484 return "SETSID";
1485
1486 case EXIT_CONFIRM:
1487 return "CONFIRM";
1488
1489 case EXIT_STDERR:
1490 return "STDERR";
1491
1492 default:
1493 return NULL;
1494 }
1495 }
1496
1497 static const char* const exec_input_table[_EXEC_INPUT_MAX] = {
1498 [EXEC_INPUT_NULL] = "null",
1499 [EXEC_INPUT_TTY] = "tty",
1500 [EXEC_INPUT_TTY_FORCE] = "tty-force",
1501 [EXEC_INPUT_TTY_FAIL] = "tty-fail"
1502 };
1503
1504 static const char* const exec_output_table[_EXEC_OUTPUT_MAX] = {
1505 [EXEC_OUTPUT_INHERIT] = "inherit",
1506 [EXEC_OUTPUT_NULL] = "null",
1507 [EXEC_OUTPUT_TTY] = "tty",
1508 [EXEC_OUTPUT_SYSLOG] = "syslog",
1509 [EXEC_OUTPUT_KERNEL] = "kernel"
1510 };
1511
1512 DEFINE_STRING_TABLE_LOOKUP(exec_output, ExecOutput);
1513
1514 DEFINE_STRING_TABLE_LOOKUP(exec_input, ExecInput);