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Revert "conf: remove extra MS_BIND with sysfs:mixed"
[mirror_lxc.git] / src / lxc / conf.c
1 /*
2 * lxc: linux Container library
3 *
4 * (C) Copyright IBM Corp. 2007, 2008
5 *
6 * Authors:
7 * Daniel Lezcano <daniel.lezcano at free.fr>
8 *
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this library; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24 #ifndef _GNU_SOURCE
25 #define _GNU_SOURCE 1
26 #endif
27 #include <arpa/inet.h>
28 #include <dirent.h>
29 #include <errno.h>
30 #include <fcntl.h>
31 #include <grp.h>
32 #include <inttypes.h>
33 #include <libgen.h>
34 #include <linux/loop.h>
35 #include <net/if.h>
36 #include <netinet/in.h>
37 #include <pwd.h>
38 #include <stdarg.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <sys/mman.h>
43 #include <sys/mount.h>
44 #include <sys/param.h>
45 #include <sys/prctl.h>
46 #include <sys/sendfile.h>
47 #include <sys/socket.h>
48 #include <sys/stat.h>
49 #include <sys/syscall.h>
50 #include <sys/sysmacros.h>
51 #include <sys/types.h>
52 #include <sys/utsname.h>
53 #include <sys/wait.h>
54 #include <time.h>
55 #include <unistd.h>
56
57 #include "af_unix.h"
58 #include "caps.h"
59 #include "cgroup.h"
60 #include "conf.h"
61 #include "config.h"
62 #include "confile.h"
63 #include "confile_utils.h"
64 #include "error.h"
65 #include "log.h"
66 #include "lsm/lsm.h"
67 #include "lxclock.h"
68 #include "lxcseccomp.h"
69 #include "macro.h"
70 #include "namespace.h"
71 #include "network.h"
72 #include "parse.h"
73 #include "raw_syscalls.h"
74 #include "ringbuf.h"
75 #include "start.h"
76 #include "storage.h"
77 #include "storage/overlay.h"
78 #include "syscall_wrappers.h"
79 #include "terminal.h"
80 #include "utils.h"
81
82 #ifdef MAJOR_IN_MKDEV
83 #include <sys/mkdev.h>
84 #endif
85
86 #ifdef HAVE_STATVFS
87 #include <sys/statvfs.h>
88 #endif
89
90 #if HAVE_PTY_H
91 #include <pty.h>
92 #else
93 #include <../include/openpty.h>
94 #endif
95
96 #if HAVE_LIBCAP
97 #include <sys/capability.h>
98 #endif
99
100 #if HAVE_SYS_PERSONALITY_H
101 #include <sys/personality.h>
102 #endif
103
104 #ifndef HAVE_STRLCAT
105 #include "include/strlcat.h"
106 #endif
107
108 #if IS_BIONIC
109 #include <../include/lxcmntent.h>
110 #else
111 #include <mntent.h>
112 #endif
113
114 #if !defined(HAVE_PRLIMIT) && defined(HAVE_PRLIMIT64)
115 #include <../include/prlimit.h>
116 #endif
117
118 lxc_log_define(conf, lxc);
119
120 /* The lxc_conf of the container currently being worked on in an API call.
121 * This is used in the error calls.
122 */
123 #ifdef HAVE_TLS
124 thread_local struct lxc_conf *current_config;
125 #else
126 struct lxc_conf *current_config;
127 #endif
128
129 char *lxchook_names[NUM_LXC_HOOKS] = {
130 "pre-start",
131 "pre-mount",
132 "mount",
133 "autodev",
134 "start",
135 "stop",
136 "post-stop",
137 "clone",
138 "destroy",
139 "start-host"
140 };
141
142 struct mount_opt {
143 char *name;
144 int clear;
145 int flag;
146 };
147
148 struct caps_opt {
149 char *name;
150 int value;
151 };
152
153 struct limit_opt {
154 char *name;
155 int value;
156 };
157
158 static struct mount_opt mount_opt[] = {
159 { "async", 1, MS_SYNCHRONOUS },
160 { "atime", 1, MS_NOATIME },
161 { "bind", 0, MS_BIND },
162 { "defaults", 0, 0 },
163 { "dev", 1, MS_NODEV },
164 { "diratime", 1, MS_NODIRATIME },
165 { "dirsync", 0, MS_DIRSYNC },
166 { "exec", 1, MS_NOEXEC },
167 { "lazytime", 0, MS_LAZYTIME },
168 { "mand", 0, MS_MANDLOCK },
169 { "noatime", 0, MS_NOATIME },
170 { "nodev", 0, MS_NODEV },
171 { "nodiratime", 0, MS_NODIRATIME },
172 { "noexec", 0, MS_NOEXEC },
173 { "nomand", 1, MS_MANDLOCK },
174 { "norelatime", 1, MS_RELATIME },
175 { "nostrictatime", 1, MS_STRICTATIME },
176 { "nosuid", 0, MS_NOSUID },
177 { "rbind", 0, MS_BIND|MS_REC },
178 { "relatime", 0, MS_RELATIME },
179 { "remount", 0, MS_REMOUNT },
180 { "ro", 0, MS_RDONLY },
181 { "rw", 1, MS_RDONLY },
182 { "strictatime", 0, MS_STRICTATIME },
183 { "suid", 1, MS_NOSUID },
184 { "sync", 0, MS_SYNCHRONOUS },
185 { NULL, 0, 0 },
186 };
187
188 static struct mount_opt propagation_opt[] = {
189 { "private", 0, MS_PRIVATE },
190 { "shared", 0, MS_SHARED },
191 { "slave", 0, MS_SLAVE },
192 { "unbindable", 0, MS_UNBINDABLE },
193 { "rprivate", 0, MS_PRIVATE|MS_REC },
194 { "rshared", 0, MS_SHARED|MS_REC },
195 { "rslave", 0, MS_SLAVE|MS_REC },
196 { "runbindable", 0, MS_UNBINDABLE|MS_REC },
197 { NULL, 0, 0 },
198 };
199
200 static struct caps_opt caps_opt[] = {
201 #if HAVE_LIBCAP
202 { "chown", CAP_CHOWN },
203 { "dac_override", CAP_DAC_OVERRIDE },
204 { "dac_read_search", CAP_DAC_READ_SEARCH },
205 { "fowner", CAP_FOWNER },
206 { "fsetid", CAP_FSETID },
207 { "kill", CAP_KILL },
208 { "setgid", CAP_SETGID },
209 { "setuid", CAP_SETUID },
210 { "setpcap", CAP_SETPCAP },
211 { "linux_immutable", CAP_LINUX_IMMUTABLE },
212 { "net_bind_service", CAP_NET_BIND_SERVICE },
213 { "net_broadcast", CAP_NET_BROADCAST },
214 { "net_admin", CAP_NET_ADMIN },
215 { "net_raw", CAP_NET_RAW },
216 { "ipc_lock", CAP_IPC_LOCK },
217 { "ipc_owner", CAP_IPC_OWNER },
218 { "sys_module", CAP_SYS_MODULE },
219 { "sys_rawio", CAP_SYS_RAWIO },
220 { "sys_chroot", CAP_SYS_CHROOT },
221 { "sys_ptrace", CAP_SYS_PTRACE },
222 { "sys_pacct", CAP_SYS_PACCT },
223 { "sys_admin", CAP_SYS_ADMIN },
224 { "sys_boot", CAP_SYS_BOOT },
225 { "sys_nice", CAP_SYS_NICE },
226 { "sys_resource", CAP_SYS_RESOURCE },
227 { "sys_time", CAP_SYS_TIME },
228 { "sys_tty_config", CAP_SYS_TTY_CONFIG },
229 { "mknod", CAP_MKNOD },
230 { "lease", CAP_LEASE },
231 #ifdef CAP_AUDIT_READ
232 { "audit_read", CAP_AUDIT_READ },
233 #endif
234 #ifdef CAP_AUDIT_WRITE
235 { "audit_write", CAP_AUDIT_WRITE },
236 #endif
237 #ifdef CAP_AUDIT_CONTROL
238 { "audit_control", CAP_AUDIT_CONTROL },
239 #endif
240 { "setfcap", CAP_SETFCAP },
241 { "mac_override", CAP_MAC_OVERRIDE },
242 { "mac_admin", CAP_MAC_ADMIN },
243 #ifdef CAP_SYSLOG
244 { "syslog", CAP_SYSLOG },
245 #endif
246 #ifdef CAP_WAKE_ALARM
247 { "wake_alarm", CAP_WAKE_ALARM },
248 #endif
249 #ifdef CAP_BLOCK_SUSPEND
250 { "block_suspend", CAP_BLOCK_SUSPEND },
251 #endif
252 #endif
253 };
254
255 static struct limit_opt limit_opt[] = {
256 #ifdef RLIMIT_AS
257 { "as", RLIMIT_AS },
258 #endif
259 #ifdef RLIMIT_CORE
260 { "core", RLIMIT_CORE },
261 #endif
262 #ifdef RLIMIT_CPU
263 { "cpu", RLIMIT_CPU },
264 #endif
265 #ifdef RLIMIT_DATA
266 { "data", RLIMIT_DATA },
267 #endif
268 #ifdef RLIMIT_FSIZE
269 { "fsize", RLIMIT_FSIZE },
270 #endif
271 #ifdef RLIMIT_LOCKS
272 { "locks", RLIMIT_LOCKS },
273 #endif
274 #ifdef RLIMIT_MEMLOCK
275 { "memlock", RLIMIT_MEMLOCK },
276 #endif
277 #ifdef RLIMIT_MSGQUEUE
278 { "msgqueue", RLIMIT_MSGQUEUE },
279 #endif
280 #ifdef RLIMIT_NICE
281 { "nice", RLIMIT_NICE },
282 #endif
283 #ifdef RLIMIT_NOFILE
284 { "nofile", RLIMIT_NOFILE },
285 #endif
286 #ifdef RLIMIT_NPROC
287 { "nproc", RLIMIT_NPROC },
288 #endif
289 #ifdef RLIMIT_RSS
290 { "rss", RLIMIT_RSS },
291 #endif
292 #ifdef RLIMIT_RTPRIO
293 { "rtprio", RLIMIT_RTPRIO },
294 #endif
295 #ifdef RLIMIT_RTTIME
296 { "rttime", RLIMIT_RTTIME },
297 #endif
298 #ifdef RLIMIT_SIGPENDING
299 { "sigpending", RLIMIT_SIGPENDING },
300 #endif
301 #ifdef RLIMIT_STACK
302 { "stack", RLIMIT_STACK },
303 #endif
304 };
305
306 static int run_buffer(char *buffer)
307 {
308 int ret;
309 char *output;
310 struct lxc_popen_FILE *f;
311
312 f = lxc_popen(buffer);
313 if (!f) {
314 SYSERROR("Failed to popen() %s", buffer);
315 return -1;
316 }
317
318 output = malloc(LXC_LOG_BUFFER_SIZE);
319 if (!output) {
320 ERROR("Failed to allocate memory for %s", buffer);
321 lxc_pclose(f);
322 return -1;
323 }
324
325 while (fgets(output, LXC_LOG_BUFFER_SIZE, f->f))
326 DEBUG("Script %s with output: %s", buffer, output);
327
328 free(output);
329
330 ret = lxc_pclose(f);
331 if (ret == -1) {
332 SYSERROR("Script exited with error");
333 return -1;
334 } else if (WIFEXITED(ret) && WEXITSTATUS(ret) != 0) {
335 ERROR("Script exited with status %d", WEXITSTATUS(ret));
336 return -1;
337 } else if (WIFSIGNALED(ret)) {
338 ERROR("Script terminated by signal %d", WTERMSIG(ret));
339 return -1;
340 }
341
342 return 0;
343 }
344
345 int run_script_argv(const char *name, unsigned int hook_version,
346 const char *section, const char *script,
347 const char *hookname, char **argv)
348 {
349 int buf_pos, i, ret;
350 char *buffer;
351 int fret = -1;
352 size_t size = 0;
353
354 if (hook_version == 0)
355 INFO("Executing script \"%s\" for container \"%s\", config "
356 "section \"%s\"", script, name, section);
357 else
358 INFO("Executing script \"%s\" for container \"%s\"", script, name);
359
360 for (i = 0; argv && argv[i]; i++)
361 size += strlen(argv[i]) + 1;
362
363 size += STRLITERALLEN("exec");
364 size++;
365 size += strlen(script);
366 size++;
367
368 if (size > INT_MAX)
369 return -EFBIG;
370
371 if (hook_version == 0) {
372 size += strlen(hookname);
373 size++;
374
375 size += strlen(name);
376 size++;
377
378 size += strlen(section);
379 size++;
380
381 if (size > INT_MAX)
382 return -EFBIG;
383 }
384
385 buffer = malloc(size);
386 if (!buffer)
387 return -ENOMEM;
388
389 if (hook_version == 0)
390 buf_pos = snprintf(buffer, size, "exec %s %s %s %s", script, name, section, hookname);
391 else
392 buf_pos = snprintf(buffer, size, "exec %s", script);
393 if (buf_pos < 0 || (size_t)buf_pos >= size) {
394 ERROR("Failed to create command line for script \"%s\"", script);
395 goto on_error;
396 }
397
398 if (hook_version == 1) {
399 ret = setenv("LXC_HOOK_TYPE", hookname, 1);
400 if (ret < 0) {
401 SYSERROR("Failed to set environment variable: "
402 "LXC_HOOK_TYPE=%s", hookname);
403 goto on_error;
404 }
405 TRACE("Set environment variable: LXC_HOOK_TYPE=%s", hookname);
406
407 ret = setenv("LXC_HOOK_SECTION", section, 1);
408 if (ret < 0) {
409 SYSERROR("Failed to set environment variable: "
410 "LXC_HOOK_SECTION=%s", section);
411 goto on_error;
412 }
413 TRACE("Set environment variable: LXC_HOOK_SECTION=%s", section);
414
415 if (strcmp(section, "net") == 0) {
416 char *parent;
417
418 if (!argv || !argv[0])
419 goto on_error;
420
421 ret = setenv("LXC_NET_TYPE", argv[0], 1);
422 if (ret < 0) {
423 SYSERROR("Failed to set environment variable: "
424 "LXC_NET_TYPE=%s", argv[0]);
425 goto on_error;
426 }
427 TRACE("Set environment variable: LXC_NET_TYPE=%s", argv[0]);
428
429 parent = argv[1] ? argv[1] : "";
430
431 if (strcmp(argv[0], "macvlan") == 0) {
432 ret = setenv("LXC_NET_PARENT", parent, 1);
433 if (ret < 0) {
434 SYSERROR("Failed to set environment "
435 "variable: LXC_NET_PARENT=%s", parent);
436 goto on_error;
437 }
438 TRACE("Set environment variable: LXC_NET_PARENT=%s", parent);
439 } else if (strcmp(argv[0], "phys") == 0) {
440 ret = setenv("LXC_NET_PARENT", parent, 1);
441 if (ret < 0) {
442 SYSERROR("Failed to set environment "
443 "variable: LXC_NET_PARENT=%s", parent);
444 goto on_error;
445 }
446 TRACE("Set environment variable: LXC_NET_PARENT=%s", parent);
447 } else if (strcmp(argv[0], "veth") == 0) {
448 char *peer = argv[2] ? argv[2] : "";
449
450 ret = setenv("LXC_NET_PEER", peer, 1);
451 if (ret < 0) {
452 SYSERROR("Failed to set environment "
453 "variable: LXC_NET_PEER=%s", peer);
454 goto on_error;
455 }
456 TRACE("Set environment variable: LXC_NET_PEER=%s", peer);
457
458 ret = setenv("LXC_NET_PARENT", parent, 1);
459 if (ret < 0) {
460 SYSERROR("Failed to set environment "
461 "variable: LXC_NET_PARENT=%s", parent);
462 goto on_error;
463 }
464 TRACE("Set environment variable: LXC_NET_PARENT=%s", parent);
465 }
466 }
467 }
468
469 for (i = 0; argv && argv[i]; i++) {
470 size_t len = size - buf_pos;
471
472 ret = snprintf(buffer + buf_pos, len, " %s", argv[i]);
473 if (ret < 0 || (size_t)ret >= len) {
474 ERROR("Failed to create command line for script \"%s\"", script);
475 goto on_error;
476 }
477 buf_pos += ret;
478 }
479
480 fret = run_buffer(buffer);
481
482 on_error:
483 free(buffer);
484 return fret;
485 }
486
487 int run_script(const char *name, const char *section, const char *script, ...)
488 {
489 int ret;
490 char *buffer, *p;
491 va_list ap;
492 size_t size = 0;
493
494 INFO("Executing script \"%s\" for container \"%s\", config section \"%s\"",
495 script, name, section);
496
497 va_start(ap, script);
498 while ((p = va_arg(ap, char *)))
499 size += strlen(p) + 1;
500 va_end(ap);
501
502 size += STRLITERALLEN("exec");
503 size += strlen(script);
504 size += strlen(name);
505 size += strlen(section);
506 size += 4;
507
508 if (size > INT_MAX)
509 return -1;
510
511 buffer = alloca(size);
512 ret = snprintf(buffer, size, "exec %s %s %s", script, name, section);
513 if (ret < 0 || ret >= size)
514 return -1;
515
516 va_start(ap, script);
517 while ((p = va_arg(ap, char *))) {
518 int len = size - ret;
519 int rc;
520 rc = snprintf(buffer + ret, len, " %s", p);
521 if (rc < 0 || rc >= len) {
522 va_end(ap);
523 return -1;
524 }
525 ret += rc;
526 }
527 va_end(ap);
528
529 return run_buffer(buffer);
530 }
531
532 /* pin_rootfs
533 * if rootfs is a directory, then open ${rootfs}/.lxc-keep for writing for
534 * the duration of the container run, to prevent the container from marking
535 * the underlying fs readonly on shutdown. unlink the file immediately so
536 * no name pollution is happens.
537 * don't unlink on NFS to avoid random named stale handles.
538 * return -1 on error.
539 * return -2 if nothing needed to be pinned.
540 * return an open fd (>=0) if we pinned it.
541 */
542 int pin_rootfs(const char *rootfs)
543 {
544 int fd, ret;
545 char absrootfspin[PATH_MAX];
546 char *absrootfs;
547 struct stat s;
548 struct statfs sfs;
549
550 if (rootfs == NULL || strlen(rootfs) == 0)
551 return -2;
552
553 absrootfs = realpath(rootfs, NULL);
554 if (!absrootfs)
555 return -2;
556
557 ret = stat(absrootfs, &s);
558 if (ret < 0) {
559 free(absrootfs);
560 return -1;
561 }
562
563 if (!S_ISDIR(s.st_mode)) {
564 free(absrootfs);
565 return -2;
566 }
567
568 ret = snprintf(absrootfspin, PATH_MAX, "%s/.lxc-keep", absrootfs);
569 free(absrootfs);
570 if (ret < 0 || ret >= PATH_MAX)
571 return -1;
572
573 fd = open(absrootfspin, O_CREAT | O_RDWR, S_IWUSR | S_IRUSR);
574 if (fd < 0)
575 return fd;
576
577 ret = fstatfs (fd, &sfs);
578 if (ret < 0)
579 return fd;
580
581 if (sfs.f_type == NFS_SUPER_MAGIC) {
582 DEBUG("Rootfs on NFS, not unlinking pin file \"%s\"", absrootfspin);
583 return fd;
584 }
585
586 (void)unlink(absrootfspin);
587
588 return fd;
589 }
590
591 /* If we are asking to remount something, make sure that any NOEXEC etc are
592 * honored.
593 */
594 unsigned long add_required_remount_flags(const char *s, const char *d,
595 unsigned long flags)
596 {
597 #ifdef HAVE_STATVFS
598 int ret;
599 struct statvfs sb;
600 unsigned long required_flags = 0;
601
602 if (!s)
603 s = d;
604
605 if (!s)
606 return flags;
607
608 ret = statvfs(s, &sb);
609 if (ret < 0)
610 return flags;
611
612 if (flags & MS_REMOUNT) {
613 if (sb.f_flag & MS_NOSUID)
614 required_flags |= MS_NOSUID;
615 if (sb.f_flag & MS_NODEV)
616 required_flags |= MS_NODEV;
617 if (sb.f_flag & MS_RDONLY)
618 required_flags |= MS_RDONLY;
619 if (sb.f_flag & MS_NOEXEC)
620 required_flags |= MS_NOEXEC;
621 }
622
623 if (sb.f_flag & MS_NOATIME)
624 required_flags |= MS_NOATIME;
625 if (sb.f_flag & MS_NODIRATIME)
626 required_flags |= MS_NODIRATIME;
627 if (sb.f_flag & MS_LAZYTIME)
628 required_flags |= MS_LAZYTIME;
629 if (sb.f_flag & MS_RELATIME)
630 required_flags |= MS_RELATIME;
631 if (sb.f_flag & MS_STRICTATIME)
632 required_flags |= MS_STRICTATIME;
633
634 return flags | required_flags;
635 #else
636 return flags;
637 #endif
638 }
639
640 static int add_shmount_to_list(struct lxc_conf *conf)
641 {
642 char new_mount[PATH_MAX];
643 /* Offset for the leading '/' since the path_cont
644 * is absolute inside the container.
645 */
646 int offset = 1, ret = -1;
647
648 ret = snprintf(new_mount, sizeof(new_mount),
649 "%s %s none bind,create=dir 0 0", conf->shmount.path_host,
650 conf->shmount.path_cont + offset);
651 if (ret < 0 || (size_t)ret >= sizeof(new_mount))
652 return -1;
653
654 return add_elem_to_mount_list(new_mount, conf);
655 }
656
657 static int lxc_mount_auto_mounts(struct lxc_conf *conf, int flags, struct lxc_handler *handler)
658 {
659 int i, r;
660 static struct {
661 int match_mask;
662 int match_flag;
663 const char *source;
664 const char *destination;
665 const char *fstype;
666 unsigned long flags;
667 const char *options;
668 } default_mounts[] = {
669 /* Read-only bind-mounting... In older kernels, doing that
670 * required to do one MS_BIND mount and then
671 * MS_REMOUNT|MS_RDONLY the same one. According to mount(2)
672 * manpage, MS_BIND honors MS_RDONLY from kernel 2.6.26
673 * onwards. However, this apparently does not work on kernel
674 * 3.8. Unfortunately, on that very same kernel, doing the same
675 * trick as above doesn't seem to work either, there one needs
676 * to ALSO specify MS_BIND for the remount, otherwise the
677 * entire fs is remounted read-only or the mount fails because
678 * it's busy... MS_REMOUNT|MS_BIND|MS_RDONLY seems to work for
679 * kernels as low as 2.6.32...
680 */
681 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, "proc", "%r/proc", "proc", MS_NODEV|MS_NOEXEC|MS_NOSUID, NULL },
682 /* proc/tty is used as a temporary placeholder for proc/sys/net which we'll move back in a few steps */
683 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, "%r/proc/sys/net", "%r/proc/tty", NULL, MS_BIND, NULL },
684 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, "%r/proc/sys", "%r/proc/sys", NULL, MS_BIND, NULL },
685 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, NULL, "%r/proc/sys", NULL, MS_REMOUNT|MS_BIND|MS_RDONLY, NULL },
686 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, "%r/proc/tty", "%r/proc/sys/net", NULL, MS_MOVE, NULL },
687 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, "%r/proc/sysrq-trigger", "%r/proc/sysrq-trigger", NULL, MS_BIND, NULL },
688 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, NULL, "%r/proc/sysrq-trigger", NULL, MS_REMOUNT|MS_BIND|MS_RDONLY, NULL },
689 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_RW, "proc", "%r/proc", "proc", MS_NODEV|MS_NOEXEC|MS_NOSUID, NULL },
690 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_RW, "sysfs", "%r/sys", "sysfs", 0, NULL },
691 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_RO, "sysfs", "%r/sys", "sysfs", MS_RDONLY, NULL },
692 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_MIXED, "sysfs", "%r/sys", "sysfs", MS_NODEV|MS_NOEXEC|MS_NOSUID, NULL },
693 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_MIXED, "%r/sys", "%r/sys", NULL, MS_BIND, NULL },
694 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_MIXED, NULL, "%r/sys", NULL, MS_REMOUNT|MS_BIND|MS_RDONLY, NULL },
695 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_MIXED, "sysfs", "%r/sys/devices/virtual/net", "sysfs", 0, NULL },
696 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_MIXED, "%r/sys/devices/virtual/net/devices/virtual/net", "%r/sys/devices/virtual/net", NULL, MS_BIND, NULL },
697 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_MIXED, NULL, "%r/sys/devices/virtual/net", NULL, MS_REMOUNT|MS_BIND|MS_NOSUID|MS_NODEV|MS_NOEXEC, NULL },
698 { 0, 0, NULL, NULL, NULL, 0, NULL }
699 };
700
701 for (i = 0; default_mounts[i].match_mask; i++) {
702 int saved_errno;
703 unsigned long mflags;
704 char *destination = NULL;
705 char *source = NULL;
706 if ((flags & default_mounts[i].match_mask) != default_mounts[i].match_flag)
707 continue;
708
709 if (default_mounts[i].source) {
710 /* will act like strdup if %r is not present */
711 source = lxc_string_replace("%r", conf->rootfs.path ? conf->rootfs.mount : "", default_mounts[i].source);
712 if (!source)
713 return -1;
714 }
715
716 if (!default_mounts[i].destination) {
717 ERROR("BUG: auto mounts destination %d was NULL", i);
718 free(source);
719 return -1;
720 }
721
722 /* will act like strdup if %r is not present */
723 destination = lxc_string_replace("%r", conf->rootfs.path ? conf->rootfs.mount : "", default_mounts[i].destination);
724 if (!destination) {
725 saved_errno = errno;
726 free(source);
727 errno = saved_errno;
728 return -1;
729 }
730
731 mflags = add_required_remount_flags(source, destination,
732 default_mounts[i].flags);
733 r = safe_mount(source, destination, default_mounts[i].fstype,
734 mflags, default_mounts[i].options,
735 conf->rootfs.path ? conf->rootfs.mount : NULL);
736 saved_errno = errno;
737 if (r < 0 && errno == ENOENT) {
738 INFO("Mount source or target for \"%s\" on \"%s\" does "
739 "not exist. Skipping", source, destination);
740 r = 0;
741 } else if (r < 0) {
742 SYSERROR("Failed to mount \"%s\" on \"%s\" with flags %lu", source, destination, mflags);
743 }
744
745 free(source);
746 free(destination);
747 if (r < 0) {
748 errno = saved_errno;
749 return -1;
750 }
751 }
752
753 if (flags & LXC_AUTO_CGROUP_MASK) {
754 int cg_flags;
755
756 cg_flags = flags & (LXC_AUTO_CGROUP_MASK & ~LXC_AUTO_CGROUP_FORCE);
757 /* If the type of cgroup mount was not specified, it depends on
758 * the container's capabilities as to what makes sense: if we
759 * have CAP_SYS_ADMIN, the read-only part can be remounted
760 * read-write anyway, so we may as well default to read-write;
761 * then the admin will not be given a false sense of security.
762 * (And if they really want mixed r/o r/w, then they can
763 * explicitly specify :mixed.) OTOH, if the container lacks
764 * CAP_SYS_ADMIN, do only default to :mixed, because then the
765 * container can't remount it read-write.
766 */
767 if (cg_flags == LXC_AUTO_CGROUP_NOSPEC || cg_flags == LXC_AUTO_CGROUP_FULL_NOSPEC) {
768 int has_sys_admin = 0;
769
770 if (!lxc_list_empty(&conf->keepcaps))
771 has_sys_admin = in_caplist(CAP_SYS_ADMIN, &conf->keepcaps);
772 else
773 has_sys_admin = !in_caplist(CAP_SYS_ADMIN, &conf->caps);
774
775 if (cg_flags == LXC_AUTO_CGROUP_NOSPEC)
776 cg_flags = has_sys_admin ? LXC_AUTO_CGROUP_RW : LXC_AUTO_CGROUP_MIXED;
777 else
778 cg_flags = has_sys_admin ? LXC_AUTO_CGROUP_FULL_RW : LXC_AUTO_CGROUP_FULL_MIXED;
779 }
780
781 if (flags & LXC_AUTO_CGROUP_FORCE)
782 cg_flags |= LXC_AUTO_CGROUP_FORCE;
783
784 if (!handler->cgroup_ops->mount(handler->cgroup_ops,
785 handler,
786 conf->rootfs.path ? conf->rootfs.mount : "",
787 cg_flags)) {
788 SYSERROR("Failed to mount \"/sys/fs/cgroup\"");
789 return -1;
790 }
791 }
792
793 if (flags & LXC_AUTO_SHMOUNTS_MASK) {
794 int ret = add_shmount_to_list(conf);
795 if (ret < 0) {
796 ERROR("Failed to add shmount entry to container config");
797 return -1;
798 }
799 }
800
801 return 0;
802 }
803
804 static int setup_utsname(struct utsname *utsname)
805 {
806 int ret;
807
808 if (!utsname)
809 return 0;
810
811 ret = sethostname(utsname->nodename, strlen(utsname->nodename));
812 if (ret < 0) {
813 SYSERROR("Failed to set the hostname to \"%s\"", utsname->nodename);
814 return -1;
815 }
816
817 INFO("Set hostname to \"%s\"", utsname->nodename);
818
819 return 0;
820 }
821
822 struct dev_symlinks {
823 const char *oldpath;
824 const char *name;
825 };
826
827 static const struct dev_symlinks dev_symlinks[] = {
828 { "/proc/self/fd", "fd" },
829 { "/proc/self/fd/0", "stdin" },
830 { "/proc/self/fd/1", "stdout" },
831 { "/proc/self/fd/2", "stderr" },
832 };
833
834 static int lxc_setup_dev_symlinks(const struct lxc_rootfs *rootfs)
835 {
836 int i, ret;
837 char path[PATH_MAX];
838 struct stat s;
839
840 for (i = 0; i < sizeof(dev_symlinks) / sizeof(dev_symlinks[0]); i++) {
841 const struct dev_symlinks *d = &dev_symlinks[i];
842
843 ret = snprintf(path, sizeof(path), "%s/dev/%s",
844 rootfs->path ? rootfs->mount : "", d->name);
845 if (ret < 0 || ret >= PATH_MAX)
846 return -1;
847
848 /* Stat the path first. If we don't get an error accept it as
849 * is and don't try to create it
850 */
851 ret = stat(path, &s);
852 if (ret == 0)
853 continue;
854
855 ret = symlink(d->oldpath, path);
856 if (ret && errno != EEXIST) {
857 if (errno == EROFS) {
858 WARN("Failed to create \"%s\". Read-only filesystem", path);
859 } else {
860 SYSERROR("Failed to create \"%s\"", path);
861 return -1;
862 }
863 }
864 }
865
866 return 0;
867 }
868
869 /* Build a space-separate list of ptys to pass to systemd. */
870 static bool append_ttyname(char **pp, char *name)
871 {
872 char *p;
873 size_t size;
874
875 if (!*pp) {
876 *pp = malloc(strlen(name) + strlen("container_ttys=") + 1);
877 if (!*pp)
878 return false;
879
880 sprintf(*pp, "container_ttys=%s", name);
881 return true;
882 }
883
884 size = strlen(*pp) + strlen(name) + 2;
885 p = realloc(*pp, size);
886 if (!p)
887 return false;
888
889 *pp = p;
890 (void)strlcat(p, " ", size);
891 (void)strlcat(p, name, size);
892
893 return true;
894 }
895
896 static int lxc_setup_ttys(struct lxc_conf *conf)
897 {
898 int i, ret;
899 const struct lxc_tty_info *ttys = &conf->ttys;
900 char *ttydir = ttys->dir;
901 char path[PATH_MAX], lxcpath[PATH_MAX];
902
903 if (!conf->rootfs.path)
904 return 0;
905
906 for (i = 0; i < ttys->max; i++) {
907 struct lxc_terminal_info *tty = &ttys->tty[i];
908
909 ret = snprintf(path, sizeof(path), "/dev/tty%d", i + 1);
910 if (ret < 0 || (size_t)ret >= sizeof(path))
911 return -1;
912
913 if (ttydir) {
914 /* create dev/lxc/tty%d" */
915 ret = snprintf(lxcpath, sizeof(lxcpath),
916 "/dev/%s/tty%d", ttydir, i + 1);
917 if (ret < 0 || (size_t)ret >= sizeof(lxcpath))
918 return -1;
919
920 ret = mknod(lxcpath, S_IFREG | 0000, 0);
921 if (ret < 0 && errno != EEXIST) {
922 SYSERROR("Failed to create \"%s\"", lxcpath);
923 return -1;
924 }
925
926 ret = unlink(path);
927 if (ret < 0 && errno != ENOENT) {
928 SYSERROR("Failed to unlink \"%s\"", path);
929 return -1;
930 }
931
932 ret = mount(tty->name, lxcpath, "none", MS_BIND, 0);
933 if (ret < 0) {
934 SYSWARN("Failed to bind mount \"%s\" onto \"%s\"",
935 tty->name, lxcpath);
936 continue;
937 }
938 DEBUG("Bind mounted \"%s\" onto \"%s\"", tty->name,
939 lxcpath);
940
941 ret = snprintf(lxcpath, sizeof(lxcpath), "%s/tty%d",
942 ttydir, i + 1);
943 if (ret < 0 || (size_t)ret >= sizeof(lxcpath))
944 return -1;
945
946 ret = symlink(lxcpath, path);
947 if (ret < 0) {
948 SYSERROR("Failed to create symlink \"%s\" -> \"%s\"",
949 path, lxcpath);
950 return -1;
951 }
952 } else {
953 /* If we populated /dev, then we need to create
954 * /dev/ttyN
955 */
956 ret = mknod(path, S_IFREG | 0000, 0);
957 if (ret < 0) /* this isn't fatal, continue */
958 SYSERROR("Failed to create \"%s\"", path);
959
960 ret = mount(tty->name, path, "none", MS_BIND, 0);
961 if (ret < 0) {
962 SYSERROR("Failed to mount '%s'->'%s'", tty->name, path);
963 continue;
964 }
965
966 DEBUG("Bind mounted \"%s\" onto \"%s\"", tty->name, path);
967 }
968
969 if (!append_ttyname(&conf->ttys.tty_names, tty->name)) {
970 ERROR("Error setting up container_ttys string");
971 return -1;
972 }
973 }
974
975 INFO("Finished setting up %zu /dev/tty<N> device(s)", ttys->max);
976 return 0;
977 }
978
979 int lxc_allocate_ttys(struct lxc_conf *conf)
980 {
981 size_t i;
982 int ret;
983 struct lxc_tty_info *ttys = &conf->ttys;
984
985 /* no tty in the configuration */
986 if (ttys->max == 0)
987 return 0;
988
989 ttys->tty = malloc(sizeof(*ttys->tty) * ttys->max);
990 if (!ttys->tty)
991 return -ENOMEM;
992
993 for (i = 0; i < ttys->max; i++) {
994 struct lxc_terminal_info *tty = &ttys->tty[i];
995
996 tty->master = -EBADF;
997 tty->slave = -EBADF;
998 ret = openpty(&tty->master, &tty->slave, NULL, NULL, NULL);
999 if (ret < 0) {
1000 SYSERROR("Failed to create tty %zu", i);
1001 ttys->max = i;
1002 lxc_delete_tty(ttys);
1003 return -ENOTTY;
1004 }
1005
1006 ret = ttyname_r(tty->slave, tty->name, sizeof(tty->name));
1007 if (ret < 0) {
1008 SYSERROR("Failed to retrieve name of tty %zu slave", i);
1009 ttys->max = i;
1010 lxc_delete_tty(ttys);
1011 return -ENOTTY;
1012 }
1013
1014 DEBUG("Created tty \"%s\" with master fd %d and slave fd %d",
1015 tty->name, tty->master, tty->slave);
1016
1017 /* Prevent leaking the file descriptors to the container */
1018 ret = fd_cloexec(tty->master, true);
1019 if (ret < 0)
1020 SYSWARN("Failed to set FD_CLOEXEC flag on master fd %d of "
1021 "tty device \"%s\"", tty->master, tty->name);
1022
1023 ret = fd_cloexec(tty->slave, true);
1024 if (ret < 0)
1025 SYSWARN("Failed to set FD_CLOEXEC flag on slave fd %d of "
1026 "tty device \"%s\"", tty->slave, tty->name);
1027
1028 tty->busy = 0;
1029 }
1030
1031 INFO("Finished creating %zu tty devices", ttys->max);
1032 return 0;
1033 }
1034
1035 void lxc_delete_tty(struct lxc_tty_info *ttys)
1036 {
1037 int i;
1038
1039 if (!ttys->tty)
1040 return;
1041
1042 for (i = 0; i < ttys->max; i++) {
1043 struct lxc_terminal_info *tty = &ttys->tty[i];
1044
1045 if (tty->master >= 0) {
1046 close(tty->master);
1047 tty->master = -EBADF;
1048 }
1049
1050 if (tty->slave >= 0) {
1051 close(tty->slave);
1052 tty->slave = -EBADF;
1053 }
1054 }
1055
1056 free(ttys->tty);
1057 ttys->tty = NULL;
1058 }
1059
1060 static int lxc_send_ttys_to_parent(struct lxc_handler *handler)
1061 {
1062 int i;
1063 int ret = -1;
1064 struct lxc_conf *conf = handler->conf;
1065 struct lxc_tty_info *ttys = &conf->ttys;
1066 int sock = handler->data_sock[0];
1067
1068 if (ttys->max == 0)
1069 return 0;
1070
1071 for (i = 0; i < ttys->max; i++) {
1072 int ttyfds[2];
1073 struct lxc_terminal_info *tty = &ttys->tty[i];
1074
1075 ttyfds[0] = tty->master;
1076 ttyfds[1] = tty->slave;
1077
1078 ret = lxc_abstract_unix_send_fds(sock, ttyfds, 2, NULL, 0);
1079 if (ret < 0)
1080 break;
1081
1082 TRACE("Sent tty \"%s\" with master fd %d and slave fd %d to "
1083 "parent", tty->name, tty->master, tty->slave);
1084 }
1085
1086 if (ret < 0)
1087 SYSERROR("Failed to send %zu ttys to parent", ttys->max);
1088 else
1089 TRACE("Sent %zu ttys to parent", ttys->max);
1090
1091 return ret;
1092 }
1093
1094 static int lxc_create_ttys(struct lxc_handler *handler)
1095 {
1096 int ret = -1;
1097 struct lxc_conf *conf = handler->conf;
1098
1099 ret = lxc_allocate_ttys(conf);
1100 if (ret < 0) {
1101 ERROR("Failed to allocate ttys");
1102 goto on_error;
1103 }
1104
1105 ret = lxc_send_ttys_to_parent(handler);
1106 if (ret < 0) {
1107 ERROR("Failed to send ttys to parent");
1108 goto on_error;
1109 }
1110
1111 if (!conf->is_execute) {
1112 ret = lxc_setup_ttys(conf);
1113 if (ret < 0) {
1114 ERROR("Failed to setup ttys");
1115 goto on_error;
1116 }
1117 }
1118
1119 if (conf->ttys.tty_names) {
1120 ret = setenv("container_ttys", conf->ttys.tty_names, 1);
1121 if (ret < 0)
1122 SYSERROR("Failed to set \"container_ttys=%s\"", conf->ttys.tty_names);
1123 }
1124
1125 ret = 0;
1126
1127 on_error:
1128 lxc_delete_tty(&conf->ttys);
1129
1130 return ret;
1131 }
1132
1133 /* Just create a path for /dev under $lxcpath/$name and in rootfs If we hit an
1134 * error, log it but don't fail yet.
1135 */
1136 static int mount_autodev(const char *name, const struct lxc_rootfs *rootfs,
1137 const char *lxcpath)
1138 {
1139 int ret;
1140 size_t clen;
1141 char *path;
1142 mode_t cur_mask;
1143
1144 INFO("Preparing \"/dev\"");
1145
1146 /* $(rootfs->mount) + "/dev/pts" + '\0' */
1147 clen = (rootfs->path ? strlen(rootfs->mount) : 0) + 9;
1148 path = alloca(clen);
1149
1150 ret = snprintf(path, clen, "%s/dev", rootfs->path ? rootfs->mount : "");
1151 if (ret < 0 || (size_t)ret >= clen)
1152 return -1;
1153
1154 cur_mask = umask(S_IXUSR | S_IXGRP | S_IXOTH);
1155 ret = mkdir(path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
1156 if (ret < 0 && errno != EEXIST) {
1157 SYSERROR("Failed to create \"/dev\" directory");
1158 ret = -errno;
1159 goto reset_umask;
1160 }
1161
1162 ret = safe_mount("none", path, "tmpfs", 0, "size=500000,mode=755",
1163 rootfs->path ? rootfs->mount : NULL);
1164 if (ret < 0) {
1165 SYSERROR("Failed to mount tmpfs on \"%s\"", path);
1166 goto reset_umask;
1167 }
1168 TRACE("Mounted tmpfs on \"%s\"", path);
1169
1170 ret = snprintf(path, clen, "%s/dev/pts", rootfs->path ? rootfs->mount : "");
1171 if (ret < 0 || (size_t)ret >= clen) {
1172 ret = -1;
1173 goto reset_umask;
1174 }
1175
1176 /* If we are running on a devtmpfs mapping, dev/pts may already exist.
1177 * If not, then create it and exit if that fails...
1178 */
1179 ret = mkdir(path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
1180 if (ret < 0 && errno != EEXIST) {
1181 SYSERROR("Failed to create directory \"%s\"", path);
1182 ret = -errno;
1183 goto reset_umask;
1184 }
1185
1186 ret = 0;
1187
1188 reset_umask:
1189 (void)umask(cur_mask);
1190
1191 INFO("Prepared \"/dev\"");
1192 return ret;
1193 }
1194
1195 struct lxc_device_node {
1196 const char *name;
1197 const mode_t mode;
1198 const int maj;
1199 const int min;
1200 };
1201
1202 static const struct lxc_device_node lxc_devices[] = {
1203 { "full", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 7 },
1204 { "null", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 3 },
1205 { "random", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 8 },
1206 { "tty", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 5, 0 },
1207 { "urandom", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 9 },
1208 { "zero", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 5 },
1209 };
1210
1211
1212 enum {
1213 LXC_DEVNODE_BIND,
1214 LXC_DEVNODE_MKNOD,
1215 LXC_DEVNODE_PARTIAL,
1216 LXC_DEVNODE_OPEN,
1217 };
1218
1219 static int lxc_fill_autodev(const struct lxc_rootfs *rootfs)
1220 {
1221 int i, ret;
1222 char path[PATH_MAX];
1223 mode_t cmask;
1224 int use_mknod = LXC_DEVNODE_MKNOD;
1225
1226 ret = snprintf(path, PATH_MAX, "%s/dev",
1227 rootfs->path ? rootfs->mount : "");
1228 if (ret < 0 || ret >= PATH_MAX)
1229 return -1;
1230
1231 /* ignore, just don't try to fill in */
1232 if (!dir_exists(path))
1233 return 0;
1234
1235 INFO("Populating \"/dev\"");
1236
1237 cmask = umask(S_IXUSR | S_IXGRP | S_IXOTH);
1238 for (i = 0; i < sizeof(lxc_devices) / sizeof(lxc_devices[0]); i++) {
1239 char hostpath[PATH_MAX];
1240 const struct lxc_device_node *device = &lxc_devices[i];
1241
1242 ret = snprintf(path, PATH_MAX, "%s/dev/%s",
1243 rootfs->path ? rootfs->mount : "", device->name);
1244 if (ret < 0 || ret >= PATH_MAX)
1245 return -1;
1246
1247 if (use_mknod >= LXC_DEVNODE_MKNOD) {
1248 ret = mknod(path, device->mode, makedev(device->maj, device->min));
1249 if (ret == 0 || (ret < 0 && errno == EEXIST)) {
1250 DEBUG("Created device node \"%s\"", path);
1251 } else if (ret < 0) {
1252 if (errno != EPERM) {
1253 SYSERROR("Failed to create device node \"%s\"", path);
1254 return -1;
1255 }
1256
1257 use_mknod = LXC_DEVNODE_BIND;
1258 }
1259
1260 /* Device nodes are fully useable. */
1261 if (use_mknod == LXC_DEVNODE_OPEN)
1262 continue;
1263
1264 if (use_mknod == LXC_DEVNODE_MKNOD) {
1265 /* See
1266 * - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=55956b59df336f6738da916dbb520b6e37df9fbd
1267 * - https://lists.linuxfoundation.org/pipermail/containers/2018-June/039176.html
1268 */
1269 ret = open(path, O_RDONLY | O_CLOEXEC);
1270 if (ret >= 0) {
1271 close(ret);
1272 /* Device nodes are fully useable. */
1273 use_mknod = LXC_DEVNODE_OPEN;
1274 continue;
1275 }
1276
1277 SYSTRACE("Failed to open \"%s\" device", path);
1278 /* Device nodes are only partially useable. */
1279 use_mknod = LXC_DEVNODE_PARTIAL;
1280 }
1281 }
1282
1283 if (use_mknod != LXC_DEVNODE_PARTIAL) {
1284 /* If we are dealing with partially functional device
1285 * nodes the prio mknod() call will have created the
1286 * device node so we can use it as a bind-mount target.
1287 */
1288 ret = mknod(path, S_IFREG | 0000, 0);
1289 if (ret < 0 && errno != EEXIST) {
1290 SYSERROR("Failed to create file \"%s\"", path);
1291 return -1;
1292 }
1293 }
1294
1295 /* Fallback to bind-mounting the device from the host. */
1296 ret = snprintf(hostpath, PATH_MAX, "/dev/%s", device->name);
1297 if (ret < 0 || ret >= PATH_MAX)
1298 return -1;
1299
1300 ret = safe_mount(hostpath, path, 0, MS_BIND, NULL,
1301 rootfs->path ? rootfs->mount : NULL);
1302 if (ret < 0) {
1303 SYSERROR("Failed to bind mount host device node \"%s\" "
1304 "onto \"%s\"", hostpath, path);
1305 return -1;
1306 }
1307 DEBUG("Bind mounted host device node \"%s\" onto \"%s\"",
1308 hostpath, path);
1309 }
1310 (void)umask(cmask);
1311
1312 INFO("Populated \"/dev\"");
1313 return 0;
1314 }
1315
1316 static int lxc_mount_rootfs(struct lxc_conf *conf)
1317 {
1318 int ret;
1319 struct lxc_storage *bdev;
1320 const struct lxc_rootfs *rootfs = &conf->rootfs;
1321
1322 if (!rootfs->path) {
1323 ret = mount("", "/", NULL, MS_SLAVE | MS_REC, 0);
1324 if (ret < 0) {
1325 SYSERROR("Failed to remount \"/\" MS_REC | MS_SLAVE");
1326 return -1;
1327 }
1328
1329 return 0;
1330 }
1331
1332 ret = access(rootfs->mount, F_OK);
1333 if (ret != 0) {
1334 SYSERROR("Failed to access to \"%s\". Check it is present",
1335 rootfs->mount);
1336 return -1;
1337 }
1338
1339 bdev = storage_init(conf);
1340 if (!bdev) {
1341 ERROR("Failed to mount rootfs \"%s\" onto \"%s\" with options \"%s\"",
1342 rootfs->path, rootfs->mount,
1343 rootfs->options ? rootfs->options : "(null)");
1344 return -1;
1345 }
1346
1347 ret = bdev->ops->mount(bdev);
1348 storage_put(bdev);
1349 if (ret < 0) {
1350 ERROR("Failed to mount rootfs \"%s\" onto \"%s\" with options \"%s\"",
1351 rootfs->path, rootfs->mount,
1352 rootfs->options ? rootfs->options : "(null)");
1353 return -1;
1354 }
1355
1356 DEBUG("Mounted rootfs \"%s\" onto \"%s\" with options \"%s\"",
1357 rootfs->path, rootfs->mount,
1358 rootfs->options ? rootfs->options : "(null)");
1359
1360 return 0;
1361 }
1362
1363 int lxc_chroot(const struct lxc_rootfs *rootfs)
1364 {
1365 int i, ret;
1366 char *p, *p2;
1367 char buf[LXC_LINELEN];
1368 char *nroot;
1369 FILE *f;
1370 char *root = rootfs->mount;
1371
1372 nroot = realpath(root, NULL);
1373 if (!nroot) {
1374 SYSERROR("Failed to resolve \"%s\"", root);
1375 return -1;
1376 }
1377
1378 ret = chdir("/");
1379 if (ret < 0) {
1380 free(nroot);
1381 return -1;
1382 }
1383
1384 /* We could use here MS_MOVE, but in userns this mount is locked and
1385 * can't be moved.
1386 */
1387 ret = mount(nroot, "/", NULL, MS_REC | MS_BIND, NULL);
1388 if (ret < 0) {
1389 SYSERROR("Failed to mount \"%s\" onto \"/\" as MS_REC | MS_BIND", nroot);
1390 free(nroot);
1391 return -1;
1392 }
1393 free(nroot);
1394
1395 ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL);
1396 if (ret < 0) {
1397 SYSERROR("Failed to remount \"/\"");
1398 return -1;
1399 }
1400
1401 /* The following code cleans up inherited mounts which are not required
1402 * for CT.
1403 *
1404 * The mountinfo file shows not all mounts, if a few points have been
1405 * unmounted between read operations from the mountinfo. So we need to
1406 * read mountinfo a few times.
1407 *
1408 * This loop can be skipped if a container uses userns, because all
1409 * inherited mounts are locked and we should live with all this trash.
1410 */
1411 for (;;) {
1412 int progress = 0;
1413
1414 f = fopen("./proc/self/mountinfo", "r");
1415 if (!f) {
1416 SYSERROR("Failed to open \"/proc/self/mountinfo\"");
1417 return -1;
1418 }
1419
1420 while (fgets(buf, LXC_LINELEN, f)) {
1421 for (p = buf, i=0; p && i < 4; i++)
1422 p = strchr(p+1, ' ');
1423
1424 if (!p)
1425 continue;
1426
1427 p2 = strchr(p+1, ' ');
1428 if (!p2)
1429 continue;
1430
1431 *p2 = '\0';
1432 *p = '.';
1433
1434 if (strcmp(p + 1, "/") == 0)
1435 continue;
1436
1437 if (strcmp(p + 1, "/proc") == 0)
1438 continue;
1439
1440 ret = umount2(p, MNT_DETACH);
1441 if (ret == 0)
1442 progress++;
1443 }
1444
1445 fclose(f);
1446
1447 if (!progress)
1448 break;
1449 }
1450
1451 /* This also can be skipped if a container uses userns. */
1452 (void)umount2("./proc", MNT_DETACH);
1453
1454 /* It is weird, but chdir("..") moves us in a new root */
1455 ret = chdir("..");
1456 if (ret < 0) {
1457 SYSERROR("Failed to chdir(\"..\")");
1458 return -1;
1459 }
1460
1461 ret = chroot(".");
1462 if (ret < 0) {
1463 SYSERROR("Failed to chroot(\".\")");
1464 return -1;
1465 }
1466
1467 return 0;
1468 }
1469
1470 /* (The following explanation is copied verbatim from the kernel.)
1471 *
1472 * pivot_root Semantics:
1473 * Moves the root file system of the current process to the directory put_old,
1474 * makes new_root as the new root file system of the current process, and sets
1475 * root/cwd of all processes which had them on the current root to new_root.
1476 *
1477 * Restrictions:
1478 * The new_root and put_old must be directories, and must not be on the
1479 * same file system as the current process root. The put_old must be
1480 * underneath new_root, i.e. adding a non-zero number of /.. to the string
1481 * pointed to by put_old must yield the same directory as new_root. No other
1482 * file system may be mounted on put_old. After all, new_root is a mountpoint.
1483 *
1484 * Also, the current root cannot be on the 'rootfs' (initial ramfs) filesystem.
1485 * See Documentation/filesystems/ramfs-rootfs-initramfs.txt for alternatives
1486 * in this situation.
1487 *
1488 * Notes:
1489 * - we don't move root/cwd if they are not at the root (reason: if something
1490 * cared enough to change them, it's probably wrong to force them elsewhere)
1491 * - it's okay to pick a root that isn't the root of a file system, e.g.
1492 * /nfs/my_root where /nfs is the mount point. It must be a mountpoint,
1493 * though, so you may need to say mount --bind /nfs/my_root /nfs/my_root
1494 * first.
1495 */
1496 static int lxc_pivot_root(const char *rootfs)
1497 {
1498 int oldroot;
1499 int newroot = -1, ret = -1;
1500
1501 oldroot = open("/", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
1502 if (oldroot < 0) {
1503 SYSERROR("Failed to open old root directory");
1504 return -1;
1505 }
1506
1507 newroot = open(rootfs, O_DIRECTORY | O_RDONLY | O_CLOEXEC);
1508 if (newroot < 0) {
1509 SYSERROR("Failed to open new root directory");
1510 goto on_error;
1511 }
1512
1513 /* change into new root fs */
1514 ret = fchdir(newroot);
1515 if (ret < 0) {
1516 ret = -1;
1517 SYSERROR("Failed to change to new rootfs \"%s\"", rootfs);
1518 goto on_error;
1519 }
1520
1521 /* pivot_root into our new root fs */
1522 ret = pivot_root(".", ".");
1523 if (ret < 0) {
1524 ret = -1;
1525 SYSERROR("Failed to pivot_root()");
1526 goto on_error;
1527 }
1528
1529 /* At this point the old-root is mounted on top of our new-root. To
1530 * unmounted it we must not be chdir'd into it, so escape back to
1531 * old-root.
1532 */
1533 ret = fchdir(oldroot);
1534 if (ret < 0) {
1535 ret = -1;
1536 SYSERROR("Failed to enter old root directory");
1537 goto on_error;
1538 }
1539
1540 /* Make oldroot rslave to make sure our umounts don't propagate to the
1541 * host.
1542 */
1543 ret = mount("", ".", "", MS_SLAVE | MS_REC, NULL);
1544 if (ret < 0) {
1545 ret = -1;
1546 SYSERROR("Failed to make oldroot rslave");
1547 goto on_error;
1548 }
1549
1550 ret = umount2(".", MNT_DETACH);
1551 if (ret < 0) {
1552 ret = -1;
1553 SYSERROR("Failed to detach old root directory");
1554 goto on_error;
1555 }
1556
1557 ret = fchdir(newroot);
1558 if (ret < 0) {
1559 ret = -1;
1560 SYSERROR("Failed to re-enter new root directory");
1561 goto on_error;
1562 }
1563
1564 ret = 0;
1565
1566 TRACE("pivot_root(\"%s\") successful", rootfs);
1567
1568 on_error:
1569 close(oldroot);
1570
1571 if (newroot >= 0)
1572 close(newroot);
1573
1574 return ret;
1575 }
1576
1577 static int lxc_setup_rootfs_switch_root(const struct lxc_rootfs *rootfs)
1578 {
1579 if (!rootfs->path) {
1580 DEBUG("Container does not have a rootfs");
1581 return 0;
1582 }
1583
1584 if (detect_ramfs_rootfs())
1585 return lxc_chroot(rootfs);
1586
1587 return lxc_pivot_root(rootfs->mount);
1588 }
1589
1590 static const struct id_map *find_mapped_nsid_entry(struct lxc_conf *conf,
1591 unsigned id,
1592 enum idtype idtype)
1593 {
1594 struct lxc_list *it;
1595 struct id_map *map;
1596 struct id_map *retmap = NULL;
1597
1598 /* Shortcut for container's root mappings. */
1599 if (id == 0) {
1600 if (idtype == ID_TYPE_UID)
1601 return conf->root_nsuid_map;
1602
1603 if (idtype == ID_TYPE_GID)
1604 return conf->root_nsgid_map;
1605 }
1606
1607 lxc_list_for_each(it, &conf->id_map) {
1608 map = it->elem;
1609 if (map->idtype != idtype)
1610 continue;
1611
1612 if (id >= map->nsid && id < map->nsid + map->range) {
1613 retmap = map;
1614 break;
1615 }
1616 }
1617
1618 return retmap;
1619 }
1620
1621 static int lxc_setup_devpts(struct lxc_conf *conf)
1622 {
1623 int ret;
1624 char **opts;
1625 char devpts_mntopts[256];
1626 char *mntopt_sets[5];
1627 char default_devpts_mntopts[256] = "gid=5,newinstance,ptmxmode=0666,mode=0620";
1628
1629 if (conf->pty_max <= 0) {
1630 DEBUG("No new devpts instance will be mounted since no pts "
1631 "devices are requested");
1632 return 0;
1633 }
1634
1635 ret = snprintf(devpts_mntopts, sizeof(devpts_mntopts), "%s,max=%zu",
1636 default_devpts_mntopts, conf->pty_max);
1637 if (ret < 0 || (size_t)ret >= sizeof(devpts_mntopts))
1638 return -1;
1639
1640 ret = umount2("/dev/pts", MNT_DETACH);
1641 if (ret < 0)
1642 SYSWARN("Failed to unmount old devpts instance");
1643 else
1644 DEBUG("Unmounted old devpts instance");
1645
1646 /* Create mountpoint for devpts instance. */
1647 ret = mkdir("/dev/pts", 0755);
1648 if (ret < 0 && errno != EEXIST) {
1649 SYSERROR("Failed to create \"/dev/pts\" directory");
1650 return -1;
1651 }
1652
1653 /* gid=5 && max= */
1654 mntopt_sets[0] = devpts_mntopts;
1655
1656 /* !gid=5 && max= */
1657 mntopt_sets[1] = devpts_mntopts + STRLITERALLEN("gid=5") + 1;
1658
1659 /* gid=5 && !max= */
1660 mntopt_sets[2] = default_devpts_mntopts;
1661
1662 /* !gid=5 && !max= */
1663 mntopt_sets[3] = default_devpts_mntopts + STRLITERALLEN("gid=5") + 1;
1664
1665 /* end */
1666 mntopt_sets[4] = NULL;
1667
1668 for (ret = -1, opts = mntopt_sets; opts && *opts; opts++) {
1669 /* mount new devpts instance */
1670 ret = mount("devpts", "/dev/pts", "devpts", MS_NOSUID | MS_NOEXEC, *opts);
1671 if (ret == 0)
1672 break;
1673 }
1674
1675 if (ret < 0) {
1676 SYSERROR("Failed to mount new devpts instance");
1677 return -1;
1678 }
1679 DEBUG("Mount new devpts instance with options \"%s\"", *opts);
1680
1681 /* Remove any pre-existing /dev/ptmx file. */
1682 ret = remove("/dev/ptmx");
1683 if (ret < 0) {
1684 if (errno != ENOENT) {
1685 SYSERROR("Failed to remove existing \"/dev/ptmx\" file");
1686 return -1;
1687 }
1688 } else {
1689 DEBUG("Removed existing \"/dev/ptmx\" file");
1690 }
1691
1692 /* Create dummy /dev/ptmx file as bind mountpoint for /dev/pts/ptmx. */
1693 ret = mknod("/dev/ptmx", S_IFREG | 0000, 0);
1694 if (ret < 0 && errno != EEXIST) {
1695 SYSERROR("Failed to create dummy \"/dev/ptmx\" file as bind mount target");
1696 return -1;
1697 }
1698 DEBUG("Created dummy \"/dev/ptmx\" file as bind mount target");
1699
1700 /* Fallback option: create symlink /dev/ptmx -> /dev/pts/ptmx */
1701 ret = mount("/dev/pts/ptmx", "/dev/ptmx", NULL, MS_BIND, NULL);
1702 if (!ret) {
1703 DEBUG("Bind mounted \"/dev/pts/ptmx\" to \"/dev/ptmx\"");
1704 return 0;
1705 } else {
1706 /* Fallthrough and try to create a symlink. */
1707 ERROR("Failed to bind mount \"/dev/pts/ptmx\" to \"/dev/ptmx\"");
1708 }
1709
1710 /* Remove the dummy /dev/ptmx file we created above. */
1711 ret = remove("/dev/ptmx");
1712 if (ret < 0) {
1713 SYSERROR("Failed to remove existing \"/dev/ptmx\"");
1714 return -1;
1715 }
1716
1717 /* Fallback option: Create symlink /dev/ptmx -> /dev/pts/ptmx. */
1718 ret = symlink("/dev/pts/ptmx", "/dev/ptmx");
1719 if (ret < 0) {
1720 SYSERROR("Failed to create symlink from \"/dev/ptmx\" to \"/dev/pts/ptmx\"");
1721 return -1;
1722 }
1723 DEBUG("Created symlink from \"/dev/ptmx\" to \"/dev/pts/ptmx\"");
1724
1725 return 0;
1726 }
1727
1728 static int setup_personality(int persona)
1729 {
1730 int ret;
1731
1732 #if HAVE_SYS_PERSONALITY_H
1733 if (persona == -1)
1734 return 0;
1735
1736 ret = personality(persona);
1737 if (ret < 0) {
1738 SYSERROR("Failed to set personality to \"0x%x\"", persona);
1739 return -1;
1740 }
1741
1742 INFO("Set personality to \"0x%x\"", persona);
1743 #endif
1744
1745 return 0;
1746 }
1747
1748 static int lxc_setup_dev_console(const struct lxc_rootfs *rootfs,
1749 const struct lxc_terminal *console)
1750 {
1751 int ret;
1752 char path[PATH_MAX];
1753 char *rootfs_path = rootfs->path ? rootfs->mount : "";
1754
1755 if (console->path && !strcmp(console->path, "none"))
1756 return 0;
1757
1758 ret = snprintf(path, sizeof(path), "%s/dev/console", rootfs_path);
1759 if (ret < 0 || (size_t)ret >= sizeof(path))
1760 return -1;
1761
1762 /* When we are asked to setup a console we remove any previous
1763 * /dev/console bind-mounts.
1764 */
1765 if (file_exists(path)) {
1766 ret = lxc_unstack_mountpoint(path, false);
1767 if (ret < 0) {
1768 SYSERROR("Failed to unmount \"%s\"", path);
1769 return -ret;
1770 } else {
1771 DEBUG("Cleared all (%d) mounts from \"%s\"", ret, path);
1772 }
1773 }
1774
1775 /* For unprivileged containers autodev or automounts will already have
1776 * taken care of creating /dev/console.
1777 */
1778 ret = mknod(path, S_IFREG | 0000, 0);
1779 if (ret < 0 && errno != EEXIST) {
1780 SYSERROR("Failed to create console");
1781 return -errno;
1782 }
1783
1784 ret = fchmod(console->slave, S_IXUSR | S_IXGRP);
1785 if (ret < 0) {
1786 SYSERROR("Failed to set mode \"0%o\" to \"%s\"",
1787 S_IXUSR | S_IXGRP, console->name);
1788 return -errno;
1789 }
1790
1791 ret = safe_mount(console->name, path, "none", MS_BIND, 0, rootfs_path);
1792 if (ret < 0) {
1793 ERROR("Failed to mount \"%s\" on \"%s\"", console->name, path);
1794 return -1;
1795 }
1796
1797 DEBUG("Mounted pts device \"%s\" onto \"%s\"", console->name, path);
1798 return 0;
1799 }
1800
1801 static int lxc_setup_ttydir_console(const struct lxc_rootfs *rootfs,
1802 const struct lxc_terminal *console,
1803 char *ttydir)
1804 {
1805 int ret;
1806 char path[PATH_MAX], lxcpath[PATH_MAX];
1807 char *rootfs_path = rootfs->path ? rootfs->mount : "";
1808
1809 if (console->path && !strcmp(console->path, "none"))
1810 return 0;
1811
1812 /* create rootfs/dev/<ttydir> directory */
1813 ret = snprintf(path, sizeof(path), "%s/dev/%s", rootfs_path, ttydir);
1814 if (ret < 0 || (size_t)ret >= sizeof(path))
1815 return -1;
1816
1817 ret = mkdir(path, 0755);
1818 if (ret && errno != EEXIST) {
1819 SYSERROR("Failed to create \"%s\"", path);
1820 return -errno;
1821 }
1822 DEBUG("Created directory for console and tty devices at \"%s\"", path);
1823
1824 ret = snprintf(lxcpath, sizeof(lxcpath), "%s/dev/%s/console", rootfs_path, ttydir);
1825 if (ret < 0 || (size_t)ret >= sizeof(lxcpath))
1826 return -1;
1827
1828 ret = mknod(lxcpath, S_IFREG | 0000, 0);
1829 if (ret < 0 && errno != EEXIST) {
1830 SYSERROR("Failed to create \"%s\"", lxcpath);
1831 return -errno;
1832 }
1833
1834 ret = snprintf(path, sizeof(path), "%s/dev/console", rootfs_path);
1835 if (ret < 0 || (size_t)ret >= sizeof(path))
1836 return -1;
1837
1838 if (file_exists(path)) {
1839 ret = lxc_unstack_mountpoint(path, false);
1840 if (ret < 0) {
1841 SYSERROR("Failed to unmount \"%s\"", path);
1842 return -ret;
1843 } else {
1844 DEBUG("Cleared all (%d) mounts from \"%s\"", ret, path);
1845 }
1846 }
1847
1848 ret = mknod(path, S_IFREG | 0000, 0);
1849 if (ret < 0 && errno != EEXIST) {
1850 SYSERROR("Failed to create console");
1851 return -errno;
1852 }
1853
1854 ret = fchmod(console->slave, S_IXUSR | S_IXGRP);
1855 if (ret < 0) {
1856 SYSERROR("Failed to set mode \"0%o\" to \"%s\"",
1857 S_IXUSR | S_IXGRP, console->name);
1858 return -errno;
1859 }
1860
1861 /* bind mount console->name to '/dev/<ttydir>/console' */
1862 ret = safe_mount(console->name, lxcpath, "none", MS_BIND, 0, rootfs_path);
1863 if (ret < 0) {
1864 ERROR("Failed to mount \"%s\" on \"%s\"", console->name, lxcpath);
1865 return -1;
1866 }
1867 DEBUG("Mounted \"%s\" onto \"%s\"", console->name, lxcpath);
1868
1869 /* bind mount '/dev/<ttydir>/console' to '/dev/console' */
1870 ret = safe_mount(lxcpath, path, "none", MS_BIND, 0, rootfs_path);
1871 if (ret < 0) {
1872 ERROR("Failed to mount \"%s\" on \"%s\"", console->name, lxcpath);
1873 return -1;
1874 }
1875 DEBUG("Mounted \"%s\" onto \"%s\"", console->name, lxcpath);
1876
1877 DEBUG("Console has been setup under \"%s\" and mounted to \"%s\"", lxcpath, path);
1878 return 0;
1879 }
1880
1881 static int lxc_setup_console(const struct lxc_rootfs *rootfs,
1882 const struct lxc_terminal *console, char *ttydir)
1883 {
1884
1885 if (!ttydir)
1886 return lxc_setup_dev_console(rootfs, console);
1887
1888 return lxc_setup_ttydir_console(rootfs, console, ttydir);
1889 }
1890
1891 static void parse_mntopt(char *opt, unsigned long *flags, char **data, size_t size)
1892 {
1893 struct mount_opt *mo;
1894
1895 /* If opt is found in mount_opt, set or clear flags.
1896 * Otherwise append it to data. */
1897
1898 for (mo = &mount_opt[0]; mo->name != NULL; mo++) {
1899 if (strncmp(opt, mo->name, strlen(mo->name)) == 0) {
1900 if (mo->clear)
1901 *flags &= ~mo->flag;
1902 else
1903 *flags |= mo->flag;
1904 return;
1905 }
1906 }
1907
1908 if (strlen(*data))
1909 (void)strlcat(*data, ",", size);
1910
1911 (void)strlcat(*data, opt, size);
1912 }
1913
1914 int parse_mntopts(const char *mntopts, unsigned long *mntflags, char **mntdata)
1915 {
1916 char *data, *p, *s;
1917 size_t size;
1918
1919 *mntdata = NULL;
1920 *mntflags = 0L;
1921
1922 if (!mntopts)
1923 return 0;
1924
1925 s = strdup(mntopts);
1926 if (!s)
1927 return -1;
1928
1929 size = strlen(s) + 1;
1930 data = malloc(size);
1931 if (!data) {
1932 free(s);
1933 return -1;
1934 }
1935 *data = 0;
1936
1937 lxc_iterate_parts(p, s, ",")
1938 parse_mntopt(p, mntflags, &data, size);
1939
1940 if (*data)
1941 *mntdata = data;
1942 else
1943 free(data);
1944 free(s);
1945
1946 return 0;
1947 }
1948
1949 static void parse_propagationopt(char *opt, unsigned long *flags)
1950 {
1951 struct mount_opt *mo;
1952
1953 /* If opt is found in propagation_opt, set or clear flags. */
1954 for (mo = &propagation_opt[0]; mo->name != NULL; mo++) {
1955 if (strncmp(opt, mo->name, strlen(mo->name)) != 0)
1956 continue;
1957
1958 if (mo->clear)
1959 *flags &= ~mo->flag;
1960 else
1961 *flags |= mo->flag;
1962
1963 return;
1964 }
1965 }
1966
1967 int parse_propagationopts(const char *mntopts, unsigned long *pflags)
1968 {
1969 char *p, *s;
1970
1971 if (!mntopts)
1972 return 0;
1973
1974 s = strdup(mntopts);
1975 if (!s) {
1976 SYSERROR("Failed to allocate memory");
1977 return -ENOMEM;
1978 }
1979
1980 *pflags = 0L;
1981 lxc_iterate_parts(p, s, ",")
1982 parse_propagationopt(p, pflags);
1983 free(s);
1984
1985 return 0;
1986 }
1987
1988 static void null_endofword(char *word)
1989 {
1990 while (*word && *word != ' ' && *word != '\t')
1991 word++;
1992 *word = '\0';
1993 }
1994
1995 /* skip @nfields spaces in @src */
1996 static char *get_field(char *src, int nfields)
1997 {
1998 int i;
1999 char *p = src;
2000
2001 for (i = 0; i < nfields; i++) {
2002 while (*p && *p != ' ' && *p != '\t')
2003 p++;
2004
2005 if (!*p)
2006 break;
2007
2008 p++;
2009 }
2010
2011 return p;
2012 }
2013
2014 static int mount_entry(const char *fsname, const char *target,
2015 const char *fstype, unsigned long mountflags,
2016 unsigned long pflags, const char *data, bool optional,
2017 bool dev, bool relative, const char *rootfs)
2018 {
2019 int ret;
2020 char srcbuf[PATH_MAX];
2021 const char *srcpath = fsname;
2022 #ifdef HAVE_STATVFS
2023 struct statvfs sb;
2024 #endif
2025
2026 if (relative) {
2027 ret = snprintf(srcbuf, PATH_MAX, "%s/%s", rootfs ? rootfs : "/", fsname ? fsname : "");
2028 if (ret < 0 || ret >= PATH_MAX) {
2029 ERROR("source path is too long");
2030 return -1;
2031 }
2032 srcpath = srcbuf;
2033 }
2034
2035 ret = safe_mount(srcpath, target, fstype, mountflags & ~MS_REMOUNT, data,
2036 rootfs);
2037 if (ret < 0) {
2038 if (optional) {
2039 SYSINFO("Failed to mount \"%s\" on \"%s\" (optional)",
2040 srcpath ? srcpath : "(null)", target);
2041 return 0;
2042 }
2043
2044 SYSERROR("Failed to mount \"%s\" on \"%s\"",
2045 srcpath ? srcpath : "(null)", target);
2046 return -1;
2047 }
2048
2049 if ((mountflags & MS_REMOUNT) || (mountflags & MS_BIND)) {
2050 unsigned long rqd_flags = 0;
2051
2052 DEBUG("Remounting \"%s\" on \"%s\" to respect bind or remount "
2053 "options", srcpath ? srcpath : "(none)", target ? target : "(none)");
2054
2055 if (mountflags & MS_RDONLY)
2056 rqd_flags |= MS_RDONLY;
2057 #ifdef HAVE_STATVFS
2058 if (srcpath && statvfs(srcpath, &sb) == 0) {
2059 unsigned long required_flags = rqd_flags;
2060
2061 if (sb.f_flag & MS_NOSUID)
2062 required_flags |= MS_NOSUID;
2063
2064 if (sb.f_flag & MS_NODEV && !dev)
2065 required_flags |= MS_NODEV;
2066
2067 if (sb.f_flag & MS_RDONLY)
2068 required_flags |= MS_RDONLY;
2069
2070 if (sb.f_flag & MS_NOEXEC)
2071 required_flags |= MS_NOEXEC;
2072
2073 DEBUG("Flags for \"%s\" were %lu, required extra flags "
2074 "are %lu", srcpath, sb.f_flag, required_flags);
2075
2076 /* If this was a bind mount request, and required_flags
2077 * does not have any flags which are not already in
2078 * mountflags, then skip the remount.
2079 */
2080 if (!(mountflags & MS_REMOUNT)) {
2081 if (!(required_flags & ~mountflags) &&
2082 rqd_flags == 0) {
2083 DEBUG("Mountflags already were %lu, "
2084 "skipping remount", mountflags);
2085 goto skipremount;
2086 }
2087 }
2088
2089 mountflags |= required_flags;
2090 }
2091 #endif
2092
2093 ret = mount(srcpath, target, fstype, mountflags | MS_REMOUNT, data);
2094 if (ret < 0) {
2095 if (optional) {
2096 SYSINFO("Failed to mount \"%s\" on \"%s\" (optional)",
2097 srcpath ? srcpath : "(null)", target);
2098 return 0;
2099 }
2100
2101 SYSERROR("Failed to mount \"%s\" on \"%s\"",
2102 srcpath ? srcpath : "(null)", target);
2103 return -1;
2104 }
2105 }
2106
2107 if (pflags) {
2108 ret = mount(NULL, target, NULL, pflags, NULL);
2109 if (ret < 0) {
2110 if (optional) {
2111 SYSINFO("Failed to change mount propagation "
2112 "for \"%s\" (optional)", target);
2113 return 0;
2114 } else {
2115 SYSERROR("Failed to change mount propagation "
2116 "for \"%s\" (optional)", target);
2117 return -1;
2118 }
2119 }
2120 DEBUG("Changed mount propagation for \"%s\"", target);
2121 }
2122
2123
2124 #ifdef HAVE_STATVFS
2125 skipremount:
2126 #endif
2127 DEBUG("Mounted \"%s\" on \"%s\" with filesystem type \"%s\"",
2128 srcpath ? srcpath : "(null)", target, fstype);
2129
2130 return 0;
2131 }
2132
2133 /* Remove "optional", "create=dir", and "create=file" from mntopt */
2134 static void cull_mntent_opt(struct mntent *mntent)
2135 {
2136 int i;
2137 char *list[] = {
2138 "create=dir",
2139 "create=file",
2140 "optional",
2141 "relative",
2142 NULL
2143 };
2144
2145 for (i = 0; list[i]; i++) {
2146 char *p, *p2;
2147
2148 p = strstr(mntent->mnt_opts, list[i]);
2149 if (!p)
2150 continue;
2151
2152 p2 = strchr(p, ',');
2153 if (!p2) {
2154 /* no more mntopts, so just chop it here */
2155 *p = '\0';
2156 continue;
2157 }
2158
2159 memmove(p, p2 + 1, strlen(p2 + 1) + 1);
2160 }
2161 }
2162
2163 static int mount_entry_create_dir_file(const struct mntent *mntent,
2164 const char *path,
2165 const struct lxc_rootfs *rootfs,
2166 const char *lxc_name, const char *lxc_path)
2167 {
2168 int ret;
2169 char *p1, *p2;
2170
2171 if (strncmp(mntent->mnt_type, "overlay", 7) == 0) {
2172 ret = ovl_mkdir(mntent, rootfs, lxc_name, lxc_path);
2173 if (ret < 0)
2174 return -1;
2175 }
2176
2177 if (hasmntopt(mntent, "create=dir")) {
2178 ret = mkdir_p(path, 0755);
2179 if (ret < 0 && errno != EEXIST) {
2180 SYSERROR("Failed to create directory \"%s\"", path);
2181 return -1;
2182 }
2183 }
2184
2185 if (!hasmntopt(mntent, "create=file"))
2186 return 0;
2187
2188 ret = access(path, F_OK);
2189 if (ret == 0)
2190 return 0;
2191
2192 p1 = strdup(path);
2193 if (!p1)
2194 return -1;
2195
2196 p2 = dirname(p1);
2197
2198 ret = mkdir_p(p2, 0755);
2199 free(p1);
2200 if (ret < 0 && errno != EEXIST) {
2201 SYSERROR("Failed to create directory \"%s\"", path);
2202 return -1;
2203 }
2204
2205 ret = mknod(path, S_IFREG | 0000, 0);
2206 if (ret < 0 && errno != EEXIST)
2207 return -errno;
2208
2209 return 0;
2210 }
2211
2212 /* rootfs, lxc_name, and lxc_path can be NULL when the container is created
2213 * without a rootfs. */
2214 static inline int mount_entry_on_generic(struct mntent *mntent,
2215 const char *path,
2216 const struct lxc_rootfs *rootfs,
2217 const char *lxc_name,
2218 const char *lxc_path)
2219 {
2220 int ret;
2221 unsigned long mntflags;
2222 char *mntdata;
2223 bool dev, optional, relative;
2224 unsigned long pflags = 0;
2225 char *rootfs_path = NULL;
2226
2227 optional = hasmntopt(mntent, "optional") != NULL;
2228 dev = hasmntopt(mntent, "dev") != NULL;
2229 relative = hasmntopt(mntent, "relative") != NULL;
2230
2231 if (rootfs && rootfs->path)
2232 rootfs_path = rootfs->mount;
2233
2234 ret = mount_entry_create_dir_file(mntent, path, rootfs, lxc_name,
2235 lxc_path);
2236 if (ret < 0) {
2237 if (optional)
2238 return 0;
2239
2240 return -1;
2241 }
2242 cull_mntent_opt(mntent);
2243
2244 ret = parse_propagationopts(mntent->mnt_opts, &pflags);
2245 if (ret < 0)
2246 return -1;
2247
2248 ret = parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata);
2249 if (ret < 0)
2250 return -1;
2251
2252 ret = mount_entry(mntent->mnt_fsname, path, mntent->mnt_type, mntflags,
2253 pflags, mntdata, optional, dev, relative, rootfs_path);
2254
2255 free(mntdata);
2256 return ret;
2257 }
2258
2259 static inline int mount_entry_on_systemfs(struct mntent *mntent)
2260 {
2261 int ret;
2262 char path[PATH_MAX];
2263
2264 /* For containers created without a rootfs all mounts are treated as
2265 * absolute paths starting at / on the host.
2266 */
2267 if (mntent->mnt_dir[0] != '/')
2268 ret = snprintf(path, sizeof(path), "/%s", mntent->mnt_dir);
2269 else
2270 ret = snprintf(path, sizeof(path), "%s", mntent->mnt_dir);
2271 if (ret < 0 || ret >= sizeof(path))
2272 return -1;
2273
2274 return mount_entry_on_generic(mntent, path, NULL, NULL, NULL);
2275 }
2276
2277 static int mount_entry_on_absolute_rootfs(struct mntent *mntent,
2278 const struct lxc_rootfs *rootfs,
2279 const char *lxc_name,
2280 const char *lxc_path)
2281 {
2282 int offset;
2283 char *aux;
2284 const char *lxcpath;
2285 char path[PATH_MAX];
2286 int ret = 0;
2287
2288 lxcpath = lxc_global_config_value("lxc.lxcpath");
2289 if (!lxcpath)
2290 return -1;
2291
2292 /* If rootfs->path is a blockdev path, allow container fstab to use
2293 * <lxcpath>/<name>/rootfs" as the target prefix.
2294 */
2295 ret = snprintf(path, PATH_MAX, "%s/%s/rootfs", lxcpath, lxc_name);
2296 if (ret < 0 || ret >= PATH_MAX)
2297 goto skipvarlib;
2298
2299 aux = strstr(mntent->mnt_dir, path);
2300 if (aux) {
2301 offset = strlen(path);
2302 goto skipabs;
2303 }
2304
2305 skipvarlib:
2306 aux = strstr(mntent->mnt_dir, rootfs->path);
2307 if (!aux) {
2308 WARN("Ignoring mount point \"%s\"", mntent->mnt_dir);
2309 return ret;
2310 }
2311 offset = strlen(rootfs->path);
2312
2313 skipabs:
2314 ret = snprintf(path, PATH_MAX, "%s/%s", rootfs->mount, aux + offset);
2315 if (ret < 0 || ret >= PATH_MAX)
2316 return -1;
2317
2318 return mount_entry_on_generic(mntent, path, rootfs, lxc_name, lxc_path);
2319 }
2320
2321 static int mount_entry_on_relative_rootfs(struct mntent *mntent,
2322 const struct lxc_rootfs *rootfs,
2323 const char *lxc_name,
2324 const char *lxc_path)
2325 {
2326 int ret;
2327 char path[PATH_MAX];
2328
2329 /* relative to root mount point */
2330 ret = snprintf(path, sizeof(path), "%s/%s", rootfs->mount, mntent->mnt_dir);
2331 if (ret < 0 || (size_t)ret >= sizeof(path))
2332 return -1;
2333
2334 return mount_entry_on_generic(mntent, path, rootfs, lxc_name, lxc_path);
2335 }
2336
2337 static int mount_file_entries(const struct lxc_conf *conf,
2338 const struct lxc_rootfs *rootfs, FILE *file,
2339 const char *lxc_name, const char *lxc_path)
2340 {
2341 char buf[4096];
2342 struct mntent mntent;
2343 int ret = -1;
2344
2345 while (getmntent_r(file, &mntent, buf, sizeof(buf))) {
2346 if (!rootfs->path)
2347 ret = mount_entry_on_systemfs(&mntent);
2348 else if (mntent.mnt_dir[0] != '/')
2349 ret = mount_entry_on_relative_rootfs(&mntent, rootfs,
2350 lxc_name, lxc_path);
2351 else
2352 ret = mount_entry_on_absolute_rootfs(&mntent, rootfs,
2353 lxc_name, lxc_path);
2354 if (ret < 0)
2355 return -1;
2356 }
2357 ret = 0;
2358
2359 INFO("Finished setting up mounts");
2360 return ret;
2361 }
2362
2363 static int setup_mount(const struct lxc_conf *conf,
2364 const struct lxc_rootfs *rootfs, const char *fstab,
2365 const char *lxc_name, const char *lxc_path)
2366 {
2367 FILE *f;
2368 int ret;
2369
2370 if (!fstab)
2371 return 0;
2372
2373 f = setmntent(fstab, "r");
2374 if (!f) {
2375 SYSERROR("Failed to open \"%s\"", fstab);
2376 return -1;
2377 }
2378
2379 ret = mount_file_entries(conf, rootfs, f, lxc_name, lxc_path);
2380 if (ret < 0)
2381 ERROR("Failed to set up mount entries");
2382
2383 endmntent(f);
2384 return ret;
2385 }
2386
2387 /*
2388 * In order for nested containers to be able to mount /proc and /sys they need
2389 * to see a "pure" proc and sysfs mount points with nothing mounted on top
2390 * (like lxcfs).
2391 * For this we provide proc and sysfs in /dev/.lxc/{proc,sys} while using an
2392 * apparmor rule to deny access to them. This is mostly for convenience: The
2393 * container's root user can mount them anyway and thus has access to the two
2394 * file systems. But a non-root user in the container should not be allowed to
2395 * access them as a side effect without explicitly allowing it.
2396 */
2397 static const char nesting_helpers[] =
2398 "proc dev/.lxc/proc proc create=dir,optional\n"
2399 "sys dev/.lxc/sys sysfs create=dir,optional\n";
2400
2401 FILE *make_anonymous_mount_file(struct lxc_list *mount,
2402 bool include_nesting_helpers)
2403 {
2404 int ret;
2405 char *mount_entry;
2406 struct lxc_list *iterator;
2407 int fd = -1;
2408
2409 fd = memfd_create(".lxc_mount_file", MFD_CLOEXEC);
2410 if (fd < 0) {
2411 char template[] = P_tmpdir "/.lxc_mount_file_XXXXXX";
2412
2413 if (errno != ENOSYS)
2414 return NULL;
2415
2416 fd = lxc_make_tmpfile(template, true);
2417 if (fd < 0) {
2418 SYSERROR("Could not create temporary mount file");
2419 return NULL;
2420 }
2421
2422 TRACE("Created temporary mount file");
2423 }
2424
2425 lxc_list_for_each (iterator, mount) {
2426 size_t len;
2427
2428 mount_entry = iterator->elem;
2429 len = strlen(mount_entry);
2430
2431 ret = lxc_write_nointr(fd, mount_entry, len);
2432 if (ret != len)
2433 goto on_error;
2434
2435 ret = lxc_write_nointr(fd, "\n", 1);
2436 if (ret != 1)
2437 goto on_error;
2438 }
2439
2440 if (include_nesting_helpers) {
2441 ret = lxc_write_nointr(fd, nesting_helpers,
2442 STRARRAYLEN(nesting_helpers));
2443 if (ret != STRARRAYLEN(nesting_helpers))
2444 goto on_error;
2445 }
2446
2447 ret = lseek(fd, 0, SEEK_SET);
2448 if (ret < 0)
2449 goto on_error;
2450
2451 return fdopen(fd, "r+");
2452
2453 on_error:
2454 SYSERROR("Failed to write mount entry to temporary mount file");
2455 close(fd);
2456 return NULL;
2457 }
2458
2459 static int setup_mount_entries(const struct lxc_conf *conf,
2460 const struct lxc_rootfs *rootfs,
2461 struct lxc_list *mount, const char *lxc_name,
2462 const char *lxc_path)
2463 {
2464 int ret;
2465 FILE *f;
2466
2467 f = make_anonymous_mount_file(mount, conf->lsm_aa_allow_nesting);
2468 if (!f)
2469 return -1;
2470
2471 ret = mount_file_entries(conf, rootfs, f, lxc_name, lxc_path);
2472 fclose(f);
2473
2474 return ret;
2475 }
2476
2477 static int parse_cap(const char *cap)
2478 {
2479 size_t i;
2480 int capid = -1;
2481 size_t end = sizeof(caps_opt) / sizeof(caps_opt[0]);
2482 char *ptr = NULL;
2483
2484 if (strcmp(cap, "none") == 0)
2485 return -2;
2486
2487 for (i = 0; i < end; i++) {
2488 if (strcmp(cap, caps_opt[i].name))
2489 continue;
2490
2491 capid = caps_opt[i].value;
2492 break;
2493 }
2494
2495 if (capid < 0) {
2496 /* Try to see if it's numeric, so the user may specify
2497 * capabilities that the running kernel knows about but we
2498 * don't
2499 */
2500 errno = 0;
2501 capid = strtol(cap, &ptr, 10);
2502 if (!ptr || *ptr != '\0' || errno != 0)
2503 /* not a valid number */
2504 capid = -1;
2505 else if (capid > lxc_caps_last_cap())
2506 /* we have a number but it's not a valid
2507 * capability */
2508 capid = -1;
2509 }
2510
2511 return capid;
2512 }
2513
2514 int in_caplist(int cap, struct lxc_list *caps)
2515 {
2516 int capid;
2517 struct lxc_list *iterator;
2518
2519 lxc_list_for_each (iterator, caps) {
2520 capid = parse_cap(iterator->elem);
2521 if (capid == cap)
2522 return 1;
2523 }
2524
2525 return 0;
2526 }
2527
2528 static int setup_caps(struct lxc_list *caps)
2529 {
2530 int capid;
2531 char *drop_entry;
2532 struct lxc_list *iterator;
2533
2534 lxc_list_for_each (iterator, caps) {
2535 int ret;
2536
2537 drop_entry = iterator->elem;
2538
2539 capid = parse_cap(drop_entry);
2540 if (capid < 0) {
2541 ERROR("unknown capability %s", drop_entry);
2542 return -1;
2543 }
2544
2545 ret = prctl(PR_CAPBSET_DROP, prctl_arg(capid), prctl_arg(0),
2546 prctl_arg(0), prctl_arg(0));
2547 if (ret < 0) {
2548 SYSERROR("Failed to remove %s capability", drop_entry);
2549 return -1;
2550 }
2551 DEBUG("Dropped %s (%d) capability", drop_entry, capid);
2552 }
2553
2554 DEBUG("Capabilities have been setup");
2555 return 0;
2556 }
2557
2558 static int dropcaps_except(struct lxc_list *caps)
2559 {
2560 int i, capid, numcaps;
2561 char *keep_entry;
2562 struct lxc_list *iterator;
2563
2564 numcaps = lxc_caps_last_cap() + 1;
2565 if (numcaps <= 0 || numcaps > 200)
2566 return -1;
2567 TRACE("Found %d capabilities", numcaps);
2568
2569 /* caplist[i] is 1 if we keep capability i */
2570 int *caplist = alloca(numcaps * sizeof(int));
2571 memset(caplist, 0, numcaps * sizeof(int));
2572
2573 lxc_list_for_each (iterator, caps) {
2574 keep_entry = iterator->elem;
2575
2576 capid = parse_cap(keep_entry);
2577 if (capid == -2)
2578 continue;
2579
2580 if (capid < 0) {
2581 ERROR("Unknown capability %s", keep_entry);
2582 return -1;
2583 }
2584
2585 DEBUG("Keep capability %s (%d)", keep_entry, capid);
2586 caplist[capid] = 1;
2587 }
2588
2589 for (i = 0; i < numcaps; i++) {
2590 int ret;
2591
2592 if (caplist[i])
2593 continue;
2594
2595 ret = prctl(PR_CAPBSET_DROP, prctl_arg(i), prctl_arg(0),
2596 prctl_arg(0), prctl_arg(0));
2597 if (ret < 0) {
2598 SYSERROR("Failed to remove capability %d", i);
2599 return -1;
2600 }
2601 }
2602
2603 DEBUG("Capabilities have been setup");
2604 return 0;
2605 }
2606
2607 static int parse_resource(const char *res)
2608 {
2609 int ret;
2610 size_t i;
2611 int resid = -1;
2612
2613 for (i = 0; i < sizeof(limit_opt) / sizeof(limit_opt[0]); ++i)
2614 if (strcmp(res, limit_opt[i].name) == 0)
2615 return limit_opt[i].value;
2616
2617 /* Try to see if it's numeric, so the user may specify
2618 * resources that the running kernel knows about but
2619 * we don't.
2620 */
2621 ret = lxc_safe_int(res, &resid);
2622 if (ret < 0)
2623 return -1;
2624
2625 return resid;
2626 }
2627
2628 int setup_resource_limits(struct lxc_list *limits, pid_t pid)
2629 {
2630 int resid;
2631 struct lxc_list *it;
2632 struct lxc_limit *lim;
2633
2634 lxc_list_for_each (it, limits) {
2635 lim = it->elem;
2636
2637 resid = parse_resource(lim->resource);
2638 if (resid < 0) {
2639 ERROR("Unknown resource %s", lim->resource);
2640 return -1;
2641 }
2642
2643 #if HAVE_PRLIMIT || HAVE_PRLIMIT64
2644 if (prlimit(pid, resid, &lim->limit, NULL) != 0) {
2645 SYSERROR("Failed to set limit %s", lim->resource);
2646 return -1;
2647 }
2648
2649 TRACE("Setup \"%s\" limit", lim->resource);
2650 #else
2651 ERROR("Cannot set limit \"%s\" as prlimit is missing", lim->resource);
2652 return -1;
2653 #endif
2654 }
2655
2656 return 0;
2657 }
2658
2659 int setup_sysctl_parameters(struct lxc_list *sysctls)
2660 {
2661 struct lxc_list *it;
2662 struct lxc_sysctl *elem;
2663 int ret = 0;
2664 char *tmp = NULL;
2665 char filename[PATH_MAX] = {0};
2666
2667 lxc_list_for_each (it, sysctls) {
2668 elem = it->elem;
2669 tmp = lxc_string_replace(".", "/", elem->key);
2670 if (!tmp) {
2671 ERROR("Failed to replace key %s", elem->key);
2672 return -1;
2673 }
2674
2675 ret = snprintf(filename, sizeof(filename), "/proc/sys/%s", tmp);
2676 free(tmp);
2677 if (ret < 0 || (size_t)ret >= sizeof(filename)) {
2678 ERROR("Error setting up sysctl parameters path");
2679 return -1;
2680 }
2681
2682 ret = lxc_write_to_file(filename, elem->value,
2683 strlen(elem->value), false, 0666);
2684 if (ret < 0) {
2685 SYSERROR("Failed to setup sysctl parameters %s to %s",
2686 elem->key, elem->value);
2687 return -1;
2688 }
2689 }
2690
2691 return 0;
2692 }
2693
2694 int setup_proc_filesystem(struct lxc_list *procs, pid_t pid)
2695 {
2696 struct lxc_list *it;
2697 struct lxc_proc *elem;
2698 int ret = 0;
2699 char *tmp = NULL;
2700 char filename[PATH_MAX] = {0};
2701
2702 lxc_list_for_each (it, procs) {
2703 elem = it->elem;
2704 tmp = lxc_string_replace(".", "/", elem->filename);
2705 if (!tmp) {
2706 ERROR("Failed to replace key %s", elem->filename);
2707 return -1;
2708 }
2709
2710 ret = snprintf(filename, sizeof(filename), "/proc/%d/%s", pid, tmp);
2711 free(tmp);
2712 if (ret < 0 || (size_t)ret >= sizeof(filename)) {
2713 ERROR("Error setting up proc filesystem path");
2714 return -1;
2715 }
2716
2717 ret = lxc_write_to_file(filename, elem->value,
2718 strlen(elem->value), false, 0666);
2719 if (ret < 0) {
2720 SYSERROR("Failed to setup proc filesystem %s to %s",
2721 elem->filename, elem->value);
2722 return -1;
2723 }
2724 }
2725
2726 return 0;
2727 }
2728
2729 static char *default_rootfs_mount = LXCROOTFSMOUNT;
2730
2731 struct lxc_conf *lxc_conf_init(void)
2732 {
2733 int i;
2734 struct lxc_conf *new;
2735
2736 new = malloc(sizeof(*new));
2737 if (!new)
2738 return NULL;
2739 memset(new, 0, sizeof(*new));
2740
2741 new->loglevel = LXC_LOG_LEVEL_NOTSET;
2742 new->personality = -1;
2743 new->autodev = 1;
2744 new->console.buffer_size = 0;
2745 new->console.log_path = NULL;
2746 new->console.log_fd = -1;
2747 new->console.log_size = 0;
2748 new->console.path = NULL;
2749 new->console.peer = -1;
2750 new->console.proxy.busy = -1;
2751 new->console.proxy.master = -1;
2752 new->console.proxy.slave = -1;
2753 new->console.master = -1;
2754 new->console.slave = -1;
2755 new->console.name[0] = '\0';
2756 memset(&new->console.ringbuf, 0, sizeof(struct lxc_ringbuf));
2757 new->maincmd_fd = -1;
2758 new->monitor_signal_pdeath = SIGKILL;
2759 new->nbd_idx = -1;
2760 new->rootfs.mount = strdup(default_rootfs_mount);
2761 if (!new->rootfs.mount) {
2762 free(new);
2763 return NULL;
2764 }
2765 new->rootfs.managed = true;
2766 new->logfd = -1;
2767 lxc_list_init(&new->cgroup);
2768 lxc_list_init(&new->cgroup2);
2769 lxc_list_init(&new->network);
2770 lxc_list_init(&new->mount_list);
2771 lxc_list_init(&new->caps);
2772 lxc_list_init(&new->keepcaps);
2773 lxc_list_init(&new->id_map);
2774 new->root_nsuid_map = NULL;
2775 new->root_nsgid_map = NULL;
2776 lxc_list_init(&new->includes);
2777 lxc_list_init(&new->aliens);
2778 lxc_list_init(&new->environment);
2779 lxc_list_init(&new->limits);
2780 lxc_list_init(&new->sysctls);
2781 lxc_list_init(&new->procs);
2782 new->hooks_version = 0;
2783 for (i = 0; i < NUM_LXC_HOOKS; i++)
2784 lxc_list_init(&new->hooks[i]);
2785 lxc_list_init(&new->groups);
2786 lxc_list_init(&new->state_clients);
2787 new->lsm_aa_profile = NULL;
2788 lxc_list_init(&new->lsm_aa_raw);
2789 new->lsm_se_context = NULL;
2790 new->tmp_umount_proc = false;
2791 new->tmp_umount_proc = 0;
2792 new->shmount.path_host = NULL;
2793 new->shmount.path_cont = NULL;
2794
2795 /* if running in a new user namespace, init and COMMAND
2796 * default to running as UID/GID 0 when using lxc-execute */
2797 new->init_uid = 0;
2798 new->init_gid = 0;
2799 memset(&new->cgroup_meta, 0, sizeof(struct lxc_cgroup));
2800 memset(&new->ns_share, 0, sizeof(char *) * LXC_NS_MAX);
2801
2802 return new;
2803 }
2804
2805 int write_id_mapping(enum idtype idtype, pid_t pid, const char *buf,
2806 size_t buf_size)
2807 {
2808 int fd, ret;
2809 char path[PATH_MAX];
2810
2811 if (geteuid() != 0 && idtype == ID_TYPE_GID) {
2812 size_t buflen;
2813
2814 ret = snprintf(path, PATH_MAX, "/proc/%d/setgroups", pid);
2815 if (ret < 0 || ret >= PATH_MAX)
2816 return -E2BIG;
2817
2818 fd = open(path, O_WRONLY);
2819 if (fd < 0 && errno != ENOENT) {
2820 SYSERROR("Failed to open \"%s\"", path);
2821 return -1;
2822 }
2823
2824 if (fd >= 0) {
2825 buflen = STRLITERALLEN("deny\n");
2826 errno = 0;
2827 ret = lxc_write_nointr(fd, "deny\n", buflen);
2828 close(fd);
2829 if (ret != buflen) {
2830 SYSERROR("Failed to write \"deny\" to "
2831 "\"/proc/%d/setgroups\"", pid);
2832 return -1;
2833 }
2834 TRACE("Wrote \"deny\" to \"/proc/%d/setgroups\"", pid);
2835 }
2836 }
2837
2838 ret = snprintf(path, PATH_MAX, "/proc/%d/%cid_map", pid,
2839 idtype == ID_TYPE_UID ? 'u' : 'g');
2840 if (ret < 0 || ret >= PATH_MAX)
2841 return -E2BIG;
2842
2843 fd = open(path, O_WRONLY);
2844 if (fd < 0) {
2845 SYSERROR("Failed to open \"%s\"", path);
2846 return -1;
2847 }
2848
2849 errno = 0;
2850 ret = lxc_write_nointr(fd, buf, buf_size);
2851 close(fd);
2852 if (ret != buf_size) {
2853 SYSERROR("Failed to write %cid mapping to \"%s\"",
2854 idtype == ID_TYPE_UID ? 'u' : 'g', path);
2855 return -1;
2856 }
2857
2858 return 0;
2859 }
2860
2861 /* Check whether a binary exist and has either CAP_SETUID, CAP_SETGID or both.
2862 *
2863 * @return 1 if functional binary was found
2864 * @return 0 if binary exists but is lacking privilege
2865 * @return -ENOENT if binary does not exist
2866 * @return -EINVAL if cap to check is neither CAP_SETUID nor CAP_SETGID
2867 */
2868 static int idmaptool_on_path_and_privileged(const char *binary, cap_value_t cap)
2869 {
2870 char *path;
2871 int ret;
2872 struct stat st;
2873 int fret = 0;
2874
2875 if (cap != CAP_SETUID && cap != CAP_SETGID)
2876 return -EINVAL;
2877
2878 path = on_path(binary, NULL);
2879 if (!path)
2880 return -ENOENT;
2881
2882 ret = stat(path, &st);
2883 if (ret < 0) {
2884 fret = -errno;
2885 goto cleanup;
2886 }
2887
2888 /* Check if the binary is setuid. */
2889 if (st.st_mode & S_ISUID) {
2890 DEBUG("The binary \"%s\" does have the setuid bit set", path);
2891 fret = 1;
2892 goto cleanup;
2893 }
2894
2895 #if HAVE_LIBCAP && LIBCAP_SUPPORTS_FILE_CAPABILITIES
2896 /* Check if it has the CAP_SETUID capability. */
2897 if ((cap & CAP_SETUID) &&
2898 lxc_file_cap_is_set(path, CAP_SETUID, CAP_EFFECTIVE) &&
2899 lxc_file_cap_is_set(path, CAP_SETUID, CAP_PERMITTED)) {
2900 DEBUG("The binary \"%s\" has CAP_SETUID in its CAP_EFFECTIVE "
2901 "and CAP_PERMITTED sets", path);
2902 fret = 1;
2903 goto cleanup;
2904 }
2905
2906 /* Check if it has the CAP_SETGID capability. */
2907 if ((cap & CAP_SETGID) &&
2908 lxc_file_cap_is_set(path, CAP_SETGID, CAP_EFFECTIVE) &&
2909 lxc_file_cap_is_set(path, CAP_SETGID, CAP_PERMITTED)) {
2910 DEBUG("The binary \"%s\" has CAP_SETGID in its CAP_EFFECTIVE "
2911 "and CAP_PERMITTED sets", path);
2912 fret = 1;
2913 goto cleanup;
2914 }
2915 #else
2916 /* If we cannot check for file capabilities we need to give the benefit
2917 * of the doubt. Otherwise we might fail even though all the necessary
2918 * file capabilities are set.
2919 */
2920 DEBUG("Cannot check for file capabilities as full capability support is "
2921 "missing. Manual intervention needed");
2922 fret = 1;
2923 #endif
2924
2925 cleanup:
2926 free(path);
2927 return fret;
2928 }
2929
2930 int lxc_map_ids_exec_wrapper(void *args)
2931 {
2932 execl("/bin/sh", "sh", "-c", (char *)args, (char *)NULL);
2933 return -1;
2934 }
2935
2936 int lxc_map_ids(struct lxc_list *idmap, pid_t pid)
2937 {
2938 int fill, left;
2939 char u_or_g;
2940 char *pos;
2941 char cmd_output[PATH_MAX];
2942 struct id_map *map;
2943 struct lxc_list *iterator;
2944 enum idtype type;
2945 /* strlen("new@idmap") = 9
2946 * +
2947 * strlen(" ") = 1
2948 * +
2949 * INTTYPE_TO_STRLEN(uint32_t)
2950 * +
2951 * strlen(" ") = 1
2952 *
2953 * We add some additional space to make sure that we really have
2954 * LXC_IDMAPLEN bytes available for our the {g,u]id mapping.
2955 */
2956 int ret = 0, gidmap = 0, uidmap = 0;
2957 char mapbuf[9 + 1 + INTTYPE_TO_STRLEN(uint32_t) + 1 + LXC_IDMAPLEN] = {0};
2958 bool had_entry = false, use_shadow = false;
2959 int hostuid, hostgid;
2960
2961 hostuid = geteuid();
2962 hostgid = getegid();
2963
2964 /* If new{g,u}idmap exists, that is, if shadow is handing out subuid
2965 * ranges, then insist that root also reserve ranges in subuid. This
2966 * will protected it by preventing another user from being handed the
2967 * range by shadow.
2968 */
2969 uidmap = idmaptool_on_path_and_privileged("newuidmap", CAP_SETUID);
2970 if (uidmap == -ENOENT)
2971 WARN("newuidmap binary is missing");
2972 else if (!uidmap)
2973 WARN("newuidmap is lacking necessary privileges");
2974
2975 gidmap = idmaptool_on_path_and_privileged("newgidmap", CAP_SETGID);
2976 if (gidmap == -ENOENT)
2977 WARN("newgidmap binary is missing");
2978 else if (!gidmap)
2979 WARN("newgidmap is lacking necessary privileges");
2980
2981 if (uidmap > 0 && gidmap > 0) {
2982 DEBUG("Functional newuidmap and newgidmap binary found");
2983 use_shadow = true;
2984 } else {
2985 /* In case unprivileged users run application containers via
2986 * execute() or a start*() there are valid cases where they may
2987 * only want to map their own {g,u}id. Let's not block them from
2988 * doing so by requiring geteuid() == 0.
2989 */
2990 DEBUG("No newuidmap and newgidmap binary found. Trying to "
2991 "write directly with euid %d", hostuid);
2992 }
2993
2994 /* Check if we really need to use newuidmap and newgidmap.
2995 * If the user is only remapping his own {g,u}id, we don't need it.
2996 */
2997 if (use_shadow && lxc_list_len(idmap) == 2) {
2998 use_shadow = false;
2999 lxc_list_for_each(iterator, idmap) {
3000 map = iterator->elem;
3001 if (map->idtype == ID_TYPE_UID && map->range == 1 &&
3002 map->nsid == hostuid && map->hostid == hostuid)
3003 continue;
3004 if (map->idtype == ID_TYPE_GID && map->range == 1 &&
3005 map->nsid == hostgid && map->hostid == hostgid)
3006 continue;
3007 use_shadow = true;
3008 break;
3009 }
3010 }
3011
3012 for (type = ID_TYPE_UID, u_or_g = 'u'; type <= ID_TYPE_GID;
3013 type++, u_or_g = 'g') {
3014 pos = mapbuf;
3015
3016 if (use_shadow)
3017 pos += sprintf(mapbuf, "new%cidmap %d", u_or_g, pid);
3018
3019 lxc_list_for_each(iterator, idmap) {
3020 map = iterator->elem;
3021 if (map->idtype != type)
3022 continue;
3023
3024 had_entry = true;
3025
3026 left = LXC_IDMAPLEN - (pos - mapbuf);
3027 fill = snprintf(pos, left, "%s%lu %lu %lu%s",
3028 use_shadow ? " " : "", map->nsid,
3029 map->hostid, map->range,
3030 use_shadow ? "" : "\n");
3031 if (fill <= 0 || fill >= left) {
3032 /* The kernel only takes <= 4k for writes to
3033 * /proc/<pid>/{g,u}id_map
3034 */
3035 SYSERROR("Too many %cid mappings defined", u_or_g);
3036 return -1;
3037 }
3038
3039 pos += fill;
3040 }
3041 if (!had_entry)
3042 continue;
3043
3044 /* Try to catch the output of new{g,u}idmap to make debugging
3045 * easier.
3046 */
3047 if (use_shadow) {
3048 ret = run_command(cmd_output, sizeof(cmd_output),
3049 lxc_map_ids_exec_wrapper,
3050 (void *)mapbuf);
3051 if (ret < 0) {
3052 ERROR("new%cidmap failed to write mapping \"%s\": %s",
3053 u_or_g, cmd_output, mapbuf);
3054 return -1;
3055 }
3056 TRACE("new%cidmap wrote mapping \"%s\"", u_or_g, mapbuf);
3057 } else {
3058 ret = write_id_mapping(type, pid, mapbuf, pos - mapbuf);
3059 if (ret < 0) {
3060 ERROR("Failed to write mapping: %s", mapbuf);
3061 return -1;
3062 }
3063 TRACE("Wrote mapping \"%s\"", mapbuf);
3064 }
3065
3066 memset(mapbuf, 0, sizeof(mapbuf));
3067 }
3068
3069 return 0;
3070 }
3071
3072 /* Return the host uid/gid to which the container root is mapped in val.
3073 * Return true if id was found, false otherwise.
3074 */
3075 bool get_mapped_rootid(struct lxc_conf *conf, enum idtype idtype,
3076 unsigned long *val)
3077 {
3078 unsigned nsid;
3079 struct id_map *map;
3080 struct lxc_list *it;
3081
3082 if (idtype == ID_TYPE_UID)
3083 nsid = (conf->root_nsuid_map != NULL) ? 0 : conf->init_uid;
3084 else
3085 nsid = (conf->root_nsgid_map != NULL) ? 0 : conf->init_gid;
3086
3087 lxc_list_for_each (it, &conf->id_map) {
3088 map = it->elem;
3089 if (map->idtype != idtype)
3090 continue;
3091 if (map->nsid != nsid)
3092 continue;
3093 *val = map->hostid;
3094 return true;
3095 }
3096
3097 return false;
3098 }
3099
3100 int mapped_hostid(unsigned id, struct lxc_conf *conf, enum idtype idtype)
3101 {
3102 struct id_map *map;
3103 struct lxc_list *it;
3104
3105 lxc_list_for_each (it, &conf->id_map) {
3106 map = it->elem;
3107 if (map->idtype != idtype)
3108 continue;
3109
3110 if (id >= map->hostid && id < map->hostid + map->range)
3111 return (id - map->hostid) + map->nsid;
3112 }
3113
3114 return -1;
3115 }
3116
3117 int find_unmapped_nsid(struct lxc_conf *conf, enum idtype idtype)
3118 {
3119 struct id_map *map;
3120 struct lxc_list *it;
3121 unsigned int freeid = 0;
3122
3123 again:
3124 lxc_list_for_each (it, &conf->id_map) {
3125 map = it->elem;
3126 if (map->idtype != idtype)
3127 continue;
3128
3129 if (freeid >= map->nsid && freeid < map->nsid + map->range) {
3130 freeid = map->nsid + map->range;
3131 goto again;
3132 }
3133 }
3134
3135 return freeid;
3136 }
3137
3138 int chown_mapped_root_exec_wrapper(void *args)
3139 {
3140 execvp("lxc-usernsexec", args);
3141 return -1;
3142 }
3143
3144 /* chown_mapped_root: for an unprivileged user with uid/gid X to
3145 * chown a dir to subuid/subgid Y, he needs to run chown as root
3146 * in a userns where nsid 0 is mapped to hostuid/hostgid Y, and
3147 * nsid Y is mapped to hostuid/hostgid X. That way, the container
3148 * root is privileged with respect to hostuid/hostgid X, allowing
3149 * him to do the chown.
3150 */
3151 int chown_mapped_root(const char *path, struct lxc_conf *conf)
3152 {
3153 uid_t rootuid, rootgid;
3154 unsigned long val;
3155 int hostuid, hostgid, ret;
3156 struct stat sb;
3157 char map1[100], map2[100], map3[100], map4[100], map5[100];
3158 char ugid[100];
3159 const char *args1[] = {"lxc-usernsexec",
3160 "-m", map1,
3161 "-m", map2,
3162 "-m", map3,
3163 "-m", map5,
3164 "--", "chown", ugid, path,
3165 NULL};
3166 const char *args2[] = {"lxc-usernsexec",
3167 "-m", map1,
3168 "-m", map2,
3169 "-m", map3,
3170 "-m", map4,
3171 "-m", map5,
3172 "--", "chown", ugid, path,
3173 NULL};
3174 char cmd_output[PATH_MAX];
3175
3176 hostuid = geteuid();
3177 hostgid = getegid();
3178
3179 if (!get_mapped_rootid(conf, ID_TYPE_UID, &val)) {
3180 ERROR("No uid mapping for container root");
3181 return -1;
3182 }
3183 rootuid = (uid_t)val;
3184
3185 if (!get_mapped_rootid(conf, ID_TYPE_GID, &val)) {
3186 ERROR("No gid mapping for container root");
3187 return -1;
3188 }
3189 rootgid = (gid_t)val;
3190
3191 if (hostuid == 0) {
3192 if (chown(path, rootuid, rootgid) < 0) {
3193 ERROR("Error chowning %s", path);
3194 return -1;
3195 }
3196
3197 return 0;
3198 }
3199
3200 if (rootuid == hostuid) {
3201 /* nothing to do */
3202 INFO("Container root is our uid; no need to chown");
3203 return 0;
3204 }
3205
3206 /* save the current gid of "path" */
3207 if (stat(path, &sb) < 0) {
3208 ERROR("Error stat %s", path);
3209 return -1;
3210 }
3211
3212 /* Update the path argument in case this was overlayfs. */
3213 args1[sizeof(args1) / sizeof(args1[0]) - 2] = path;
3214 args2[sizeof(args2) / sizeof(args2[0]) - 2] = path;
3215
3216 /*
3217 * A file has to be group-owned by a gid mapped into the
3218 * container, or the container won't be privileged over it.
3219 */
3220 DEBUG("trying to chown \"%s\" to %d", path, hostgid);
3221 if (sb.st_uid == hostuid &&
3222 mapped_hostid(sb.st_gid, conf, ID_TYPE_GID) < 0 &&
3223 chown(path, -1, hostgid) < 0) {
3224 ERROR("Failed chgrping %s", path);
3225 return -1;
3226 }
3227
3228 /* "u:0:rootuid:1" */
3229 ret = snprintf(map1, 100, "u:0:%d:1", rootuid);
3230 if (ret < 0 || ret >= 100) {
3231 ERROR("Error uid printing map string");
3232 return -1;
3233 }
3234
3235 /* "u:hostuid:hostuid:1" */
3236 ret = snprintf(map2, 100, "u:%d:%d:1", hostuid, hostuid);
3237 if (ret < 0 || ret >= 100) {
3238 ERROR("Error uid printing map string");
3239 return -1;
3240 }
3241
3242 /* "g:0:rootgid:1" */
3243 ret = snprintf(map3, 100, "g:0:%d:1", rootgid);
3244 if (ret < 0 || ret >= 100) {
3245 ERROR("Error gid printing map string");
3246 return -1;
3247 }
3248
3249 /* "g:pathgid:rootgid+pathgid:1" */
3250 ret = snprintf(map4, 100, "g:%d:%d:1", (gid_t)sb.st_gid,
3251 rootgid + (gid_t)sb.st_gid);
3252 if (ret < 0 || ret >= 100) {
3253 ERROR("Error gid printing map string");
3254 return -1;
3255 }
3256
3257 /* "g:hostgid:hostgid:1" */
3258 ret = snprintf(map5, 100, "g:%d:%d:1", hostgid, hostgid);
3259 if (ret < 0 || ret >= 100) {
3260 ERROR("Error gid printing map string");
3261 return -1;
3262 }
3263
3264 /* "0:pathgid" (chown) */
3265 ret = snprintf(ugid, 100, "0:%d", (gid_t)sb.st_gid);
3266 if (ret < 0 || ret >= 100) {
3267 ERROR("Error owner printing format string for chown");
3268 return -1;
3269 }
3270
3271 if (hostgid == sb.st_gid)
3272 ret = run_command(cmd_output, sizeof(cmd_output),
3273 chown_mapped_root_exec_wrapper,
3274 (void *)args1);
3275 else
3276 ret = run_command(cmd_output, sizeof(cmd_output),
3277 chown_mapped_root_exec_wrapper,
3278 (void *)args2);
3279 if (ret < 0)
3280 ERROR("lxc-usernsexec failed: %s", cmd_output);
3281
3282 return ret;
3283 }
3284
3285 /* NOTE: Must not be called from inside the container namespace! */
3286 int lxc_create_tmp_proc_mount(struct lxc_conf *conf)
3287 {
3288 int mounted;
3289
3290 mounted = lxc_mount_proc_if_needed(conf->rootfs.path ? conf->rootfs.mount : "");
3291 if (mounted == -1) {
3292 SYSERROR("Failed to mount proc in the container");
3293 /* continue only if there is no rootfs */
3294 if (conf->rootfs.path)
3295 return -1;
3296 } else if (mounted == 1) {
3297 conf->tmp_umount_proc = true;
3298 }
3299
3300 return 0;
3301 }
3302
3303 void tmp_proc_unmount(struct lxc_conf *lxc_conf)
3304 {
3305 if (!lxc_conf->tmp_umount_proc)
3306 return;
3307
3308 (void)umount2("/proc", MNT_DETACH);
3309 lxc_conf->tmp_umount_proc = false;
3310 }
3311
3312 /* Walk /proc/mounts and change any shared entries to slave. */
3313 void remount_all_slave(void)
3314 {
3315 int memfd, mntinfo_fd, ret;
3316 ssize_t copied;
3317 FILE *f;
3318 size_t len = 0;
3319 char *line = NULL;
3320
3321 mntinfo_fd = open("/proc/self/mountinfo", O_RDONLY | O_CLOEXEC);
3322 if (mntinfo_fd < 0) {
3323 SYSERROR("Failed to open \"/proc/self/mountinfo\"");
3324 return;
3325 }
3326
3327 memfd = memfd_create(".lxc_mountinfo", MFD_CLOEXEC);
3328 if (memfd < 0) {
3329 char template[] = P_tmpdir "/.lxc_mountinfo_XXXXXX";
3330
3331 if (errno != ENOSYS) {
3332 SYSERROR("Failed to create temporary in-memory file");
3333 close(mntinfo_fd);
3334 return;
3335 }
3336
3337 memfd = lxc_make_tmpfile(template, true);
3338 if (memfd < 0) {
3339 close(mntinfo_fd);
3340 WARN("Failed to create temporary file");
3341 return;
3342 }
3343 }
3344
3345 again:
3346 copied = lxc_sendfile_nointr(memfd, mntinfo_fd, NULL, LXC_SENDFILE_MAX);
3347 if (copied < 0) {
3348 if (errno == EINTR)
3349 goto again;
3350
3351 SYSERROR("Failed to copy \"/proc/self/mountinfo\"");
3352 close(mntinfo_fd);
3353 close(memfd);
3354 return;
3355 }
3356 close(mntinfo_fd);
3357
3358 /* After a successful fdopen() memfd will be closed when calling
3359 * fclose(f). Calling close(memfd) afterwards is undefined.
3360 */
3361 ret = lseek(memfd, 0, SEEK_SET);
3362 if (ret < 0) {
3363 SYSERROR("Failed to reset file descriptor offset");
3364 close(memfd);
3365 return;
3366 }
3367
3368 f = fdopen(memfd, "r");
3369 if (!f) {
3370 SYSERROR("Failed to open copy of \"/proc/self/mountinfo\" to mark "
3371 "all shared. Continuing");
3372 close(memfd);
3373 return;
3374 }
3375
3376 while (getline(&line, &len, f) != -1) {
3377 int ret;
3378 char *opts, *target;
3379
3380 target = get_field(line, 4);
3381 if (!target)
3382 continue;
3383
3384 opts = get_field(target, 2);
3385 if (!opts)
3386 continue;
3387
3388 null_endofword(opts);
3389 if (!strstr(opts, "shared"))
3390 continue;
3391
3392 null_endofword(target);
3393 ret = mount(NULL, target, NULL, MS_SLAVE, NULL);
3394 if (ret < 0) {
3395 SYSERROR("Failed to make \"%s\" MS_SLAVE", target);
3396 ERROR("Continuing...");
3397 continue;
3398 }
3399 TRACE("Remounted \"%s\" as MS_SLAVE", target);
3400 }
3401 fclose(f);
3402 free(line);
3403 TRACE("Remounted all mount table entries as MS_SLAVE");
3404 }
3405
3406 static int lxc_execute_bind_init(struct lxc_handler *handler)
3407 {
3408 int ret;
3409 char *p;
3410 char path[PATH_MAX], destpath[PATH_MAX];
3411 struct lxc_conf *conf = handler->conf;
3412
3413 /* If init exists in the container, don't bind mount a static one */
3414 p = choose_init(conf->rootfs.mount);
3415 if (p) {
3416 char *old = p;
3417
3418 p = strdup(old + strlen(conf->rootfs.mount));
3419 free(old);
3420 if (!p)
3421 return -ENOMEM;
3422
3423 INFO("Found existing init at \"%s\"", p);
3424 goto out;
3425 }
3426
3427 ret = snprintf(path, PATH_MAX, SBINDIR "/init.lxc.static");
3428 if (ret < 0 || ret >= PATH_MAX)
3429 return -1;
3430
3431 if (!file_exists(path)) {
3432 ERROR("The file \"%s\" does not exist on host", path);
3433 return -1;
3434 }
3435
3436 ret = snprintf(destpath, PATH_MAX, "%s" P_tmpdir "%s", conf->rootfs.mount, "/.lxc-init");
3437 if (ret < 0 || ret >= PATH_MAX)
3438 return -1;
3439
3440 if (!file_exists(destpath)) {
3441 ret = mknod(destpath, S_IFREG | 0000, 0);
3442 if (ret < 0 && errno != EEXIST) {
3443 SYSERROR("Failed to create dummy \"%s\" file as bind mount target", destpath);
3444 return -1;
3445 }
3446 }
3447
3448 ret = safe_mount(path, destpath, "none", MS_BIND, NULL, conf->rootfs.mount);
3449 if (ret < 0) {
3450 SYSERROR("Failed to bind mount lxc.init.static into container");
3451 return -1;
3452 }
3453
3454 p = strdup(destpath + strlen(conf->rootfs.mount));
3455 if (!p)
3456 return -ENOMEM;
3457
3458 INFO("Bind mounted lxc.init.static into container at \"%s\"", path);
3459 out:
3460 ((struct execute_args *)handler->data)->init_fd = -1;
3461 ((struct execute_args *)handler->data)->init_path = p;
3462 return 0;
3463 }
3464
3465 /* This does the work of remounting / if it is shared, calling the container
3466 * pre-mount hooks, and mounting the rootfs.
3467 */
3468 int lxc_setup_rootfs_prepare_root(struct lxc_conf *conf, const char *name,
3469 const char *lxcpath)
3470 {
3471 int ret;
3472
3473 if (conf->rootfs_setup) {
3474 const char *path = conf->rootfs.mount;
3475
3476 /* The rootfs was set up in another namespace. bind-mount it to
3477 * give us a mount in our own ns so we can pivot_root to it
3478 */
3479 ret = mount(path, path, "rootfs", MS_BIND, NULL);
3480 if (ret < 0) {
3481 ERROR("Failed to bind mount container / onto itself");
3482 return -1;
3483 }
3484
3485 TRACE("Bind mounted container / onto itself");
3486 return 0;
3487 }
3488
3489 remount_all_slave();
3490
3491 ret = run_lxc_hooks(name, "pre-mount", conf, NULL);
3492 if (ret < 0) {
3493 ERROR("Failed to run pre-mount hooks");
3494 return -1;
3495 }
3496
3497 ret = lxc_mount_rootfs(conf);
3498 if (ret < 0) {
3499 ERROR("Failed to setup rootfs for");
3500 return -1;
3501 }
3502
3503 conf->rootfs_setup = true;
3504 return 0;
3505 }
3506
3507 static bool verify_start_hooks(struct lxc_conf *conf)
3508 {
3509 char path[PATH_MAX];
3510 struct lxc_list *it;
3511
3512 lxc_list_for_each (it, &conf->hooks[LXCHOOK_START]) {
3513 int ret;
3514 char *hookname = it->elem;
3515
3516 ret = snprintf(path, PATH_MAX, "%s%s",
3517 conf->rootfs.path ? conf->rootfs.mount : "",
3518 hookname);
3519 if (ret < 0 || ret >= PATH_MAX)
3520 return false;
3521
3522 ret = access(path, X_OK);
3523 if (ret < 0) {
3524 SYSERROR("Start hook \"%s\" not found in container",
3525 hookname);
3526 return false;
3527 }
3528
3529 return true;
3530 }
3531
3532 return true;
3533 }
3534
3535 static bool execveat_supported(void)
3536 {
3537 lxc_raw_execveat(-1, "", NULL, NULL, AT_EMPTY_PATH);
3538 if (errno == ENOSYS)
3539 return false;
3540
3541 return true;
3542 }
3543
3544 int lxc_setup(struct lxc_handler *handler)
3545 {
3546 int ret;
3547 const char *lxcpath = handler->lxcpath, *name = handler->name;
3548 struct lxc_conf *lxc_conf = handler->conf;
3549
3550 ret = lxc_setup_rootfs_prepare_root(lxc_conf, name, lxcpath);
3551 if (ret < 0) {
3552 ERROR("Failed to setup rootfs");
3553 return -1;
3554 }
3555
3556 if (handler->nsfd[LXC_NS_UTS] == -1) {
3557 ret = setup_utsname(lxc_conf->utsname);
3558 if (ret < 0) {
3559 ERROR("Failed to setup the utsname %s", name);
3560 return -1;
3561 }
3562 }
3563
3564 ret = lxc_setup_keyring();
3565 if (ret < 0)
3566 return -1;
3567
3568 ret = lxc_setup_network_in_child_namespaces(lxc_conf, &lxc_conf->network);
3569 if (ret < 0) {
3570 ERROR("Failed to setup network");
3571 return -1;
3572 }
3573
3574 ret = lxc_network_send_name_and_ifindex_to_parent(handler);
3575 if (ret < 0) {
3576 ERROR("Failed to send network device names and ifindices to parent");
3577 return -1;
3578 }
3579
3580 if (lxc_conf->autodev > 0) {
3581 ret = mount_autodev(name, &lxc_conf->rootfs, lxcpath);
3582 if (ret < 0) {
3583 ERROR("Failed to mount \"/dev\"");
3584 return -1;
3585 }
3586 }
3587
3588 /* Do automatic mounts (mainly /proc and /sys), but exclude those that
3589 * need to wait until other stuff has finished.
3590 */
3591 ret = lxc_mount_auto_mounts(lxc_conf, lxc_conf->auto_mounts & ~LXC_AUTO_CGROUP_MASK, handler);
3592 if (ret < 0) {
3593 ERROR("Failed to setup first automatic mounts");
3594 return -1;
3595 }
3596
3597 ret = setup_mount(lxc_conf, &lxc_conf->rootfs, lxc_conf->fstab, name, lxcpath);
3598 if (ret < 0) {
3599 ERROR("Failed to setup mounts");
3600 return -1;
3601 }
3602
3603 if (lxc_conf->is_execute) {
3604 if (execveat_supported()) {
3605 int fd;
3606 char path[PATH_MAX];
3607
3608 ret = snprintf(path, PATH_MAX, SBINDIR "/init.lxc.static");
3609 if (ret < 0 || ret >= PATH_MAX) {
3610 ERROR("Path to init.lxc.static too long");
3611 return -1;
3612 }
3613
3614 fd = open(path, O_PATH | O_CLOEXEC);
3615 if (fd < 0) {
3616 SYSERROR("Unable to open lxc.init.static");
3617 return -1;
3618 }
3619
3620 ((struct execute_args *)handler->data)->init_fd = fd;
3621 ((struct execute_args *)handler->data)->init_path = NULL;
3622 } else {
3623 ret = lxc_execute_bind_init(handler);
3624 if (ret < 0) {
3625 ERROR("Failed to bind-mount the lxc init system");
3626 return -1;
3627 }
3628 }
3629 }
3630
3631 /* Now mount only cgroups, if wanted. Before, /sys could not have been
3632 * mounted. It is guaranteed to be mounted now either through
3633 * automatically or via fstab entries.
3634 */
3635 ret = lxc_mount_auto_mounts(lxc_conf, lxc_conf->auto_mounts & LXC_AUTO_CGROUP_MASK, handler);
3636 if (ret < 0) {
3637 ERROR("Failed to setup remaining automatic mounts");
3638 return -1;
3639 }
3640
3641 ret = run_lxc_hooks(name, "mount", lxc_conf, NULL);
3642 if (ret < 0) {
3643 ERROR("Failed to run mount hooks");
3644 return -1;
3645 }
3646
3647 if (lxc_conf->autodev > 0) {
3648 ret = run_lxc_hooks(name, "autodev", lxc_conf, NULL);
3649 if (ret < 0) {
3650 ERROR("Failed to run autodev hooks");
3651 return -1;
3652 }
3653
3654 ret = lxc_fill_autodev(&lxc_conf->rootfs);
3655 if (ret < 0) {
3656 ERROR("Failed to populate \"/dev\"");
3657 return -1;
3658 }
3659 }
3660
3661 if (!lxc_list_empty(&lxc_conf->mount_list)) {
3662 ret = setup_mount_entries(lxc_conf, &lxc_conf->rootfs,
3663 &lxc_conf->mount_list, name, lxcpath);
3664 if (ret < 0) {
3665 ERROR("Failed to setup mount entries");
3666 return -1;
3667 }
3668 }
3669
3670 /* Make sure any start hooks are in the container */
3671 if (!verify_start_hooks(lxc_conf)) {
3672 ERROR("Failed to verify start hooks");
3673 return -1;
3674 }
3675
3676 ret = lxc_setup_console(&lxc_conf->rootfs, &lxc_conf->console,
3677 lxc_conf->ttys.dir);
3678 if (ret < 0) {
3679 ERROR("Failed to setup console");
3680 return -1;
3681 }
3682
3683 ret = lxc_setup_dev_symlinks(&lxc_conf->rootfs);
3684 if (ret < 0) {
3685 ERROR("Failed to setup \"/dev\" symlinks");
3686 return -1;
3687 }
3688
3689 ret = lxc_create_tmp_proc_mount(lxc_conf);
3690 if (ret < 0) {
3691 ERROR("Failed to \"/proc\" LSMs");
3692 return -1;
3693 }
3694
3695 ret = lxc_setup_rootfs_switch_root(&lxc_conf->rootfs);
3696 if (ret < 0) {
3697 ERROR("Failed to pivot root into rootfs");
3698 return -1;
3699 }
3700
3701 ret = lxc_setup_devpts(lxc_conf);
3702 if (ret < 0) {
3703 ERROR("Failed to setup new devpts instance");
3704 return -1;
3705 }
3706
3707 ret = lxc_create_ttys(handler);
3708 if (ret < 0)
3709 return -1;
3710
3711 ret = setup_personality(lxc_conf->personality);
3712 if (ret < 0) {
3713 ERROR("Failed to set personality");
3714 return -1;
3715 }
3716
3717 /* Set sysctl value to a path under /proc/sys as determined from the
3718 * key. For e.g. net.ipv4.ip_forward translated to
3719 * /proc/sys/net/ipv4/ip_forward.
3720 */
3721 if (!lxc_list_empty(&lxc_conf->sysctls)) {
3722 ret = setup_sysctl_parameters(&lxc_conf->sysctls);
3723 if (ret < 0) {
3724 ERROR("Failed to setup sysctl parameters");
3725 return -1;
3726 }
3727 }
3728
3729 if (!lxc_list_empty(&lxc_conf->keepcaps)) {
3730 if (!lxc_list_empty(&lxc_conf->caps)) {
3731 ERROR("Container requests lxc.cap.drop and "
3732 "lxc.cap.keep: either use lxc.cap.drop or "
3733 "lxc.cap.keep, not both");
3734 return -1;
3735 }
3736
3737 if (dropcaps_except(&lxc_conf->keepcaps)) {
3738 ERROR("Failed to keep capabilities");
3739 return -1;
3740 }
3741 } else if (setup_caps(&lxc_conf->caps)) {
3742 ERROR("Failed to drop capabilities");
3743 return -1;
3744 }
3745
3746 NOTICE("The container \"%s\" is set up", name);
3747
3748 return 0;
3749 }
3750
3751 int run_lxc_hooks(const char *name, char *hookname, struct lxc_conf *conf,
3752 char *argv[])
3753 {
3754 struct lxc_list *it;
3755 int which = -1;
3756
3757 if (strcmp(hookname, "pre-start") == 0)
3758 which = LXCHOOK_PRESTART;
3759 else if (strcmp(hookname, "start-host") == 0)
3760 which = LXCHOOK_START_HOST;
3761 else if (strcmp(hookname, "pre-mount") == 0)
3762 which = LXCHOOK_PREMOUNT;
3763 else if (strcmp(hookname, "mount") == 0)
3764 which = LXCHOOK_MOUNT;
3765 else if (strcmp(hookname, "autodev") == 0)
3766 which = LXCHOOK_AUTODEV;
3767 else if (strcmp(hookname, "start") == 0)
3768 which = LXCHOOK_START;
3769 else if (strcmp(hookname, "stop") == 0)
3770 which = LXCHOOK_STOP;
3771 else if (strcmp(hookname, "post-stop") == 0)
3772 which = LXCHOOK_POSTSTOP;
3773 else if (strcmp(hookname, "clone") == 0)
3774 which = LXCHOOK_CLONE;
3775 else if (strcmp(hookname, "destroy") == 0)
3776 which = LXCHOOK_DESTROY;
3777 else
3778 return -1;
3779
3780 lxc_list_for_each (it, &conf->hooks[which]) {
3781 int ret;
3782 char *hook = it->elem;
3783
3784 ret = run_script_argv(name, conf->hooks_version, "lxc", hook,
3785 hookname, argv);
3786 if (ret < 0)
3787 return -1;
3788 }
3789
3790 return 0;
3791 }
3792
3793 int lxc_clear_config_caps(struct lxc_conf *c)
3794 {
3795 struct lxc_list *it, *next;
3796
3797 lxc_list_for_each_safe (it, &c->caps, next) {
3798 lxc_list_del(it);
3799 free(it->elem);
3800 free(it);
3801 }
3802
3803 return 0;
3804 }
3805
3806 static int lxc_free_idmap(struct lxc_list *id_map)
3807 {
3808 struct lxc_list *it, *next;
3809
3810 lxc_list_for_each_safe (it, id_map, next) {
3811 lxc_list_del(it);
3812 free(it->elem);
3813 free(it);
3814 }
3815
3816 return 0;
3817 }
3818
3819 int lxc_clear_idmaps(struct lxc_conf *c)
3820 {
3821 return lxc_free_idmap(&c->id_map);
3822 }
3823
3824 int lxc_clear_config_keepcaps(struct lxc_conf *c)
3825 {
3826 struct lxc_list *it, *next;
3827
3828 lxc_list_for_each_safe (it, &c->keepcaps, next) {
3829 lxc_list_del(it);
3830 free(it->elem);
3831 free(it);
3832 }
3833
3834 return 0;
3835 }
3836
3837 int lxc_clear_cgroups(struct lxc_conf *c, const char *key, int version)
3838 {
3839 char *global_token, *namespaced_token;
3840 size_t namespaced_token_len;
3841 struct lxc_list *it, *next, *list;
3842 const char *k = key;
3843 bool all = false;
3844
3845 if (version == CGROUP2_SUPER_MAGIC) {
3846 global_token = "lxc.cgroup2";
3847 namespaced_token = "lxc.cgroup2.";
3848 namespaced_token_len = STRLITERALLEN("lxc.cgroup2.");
3849 list = &c->cgroup2;
3850 } else if (version == CGROUP_SUPER_MAGIC) {
3851 global_token = "lxc.cgroup";
3852 namespaced_token = "lxc.cgroup.";
3853 namespaced_token_len = STRLITERALLEN("lxc.cgroup.");
3854 list = &c->cgroup;
3855 } else {
3856 return -EINVAL;
3857 }
3858
3859 if (strcmp(key, global_token) == 0)
3860 all = true;
3861 else if (strncmp(key, namespaced_token, namespaced_token_len) == 0)
3862 k += namespaced_token_len;
3863 else
3864 return -EINVAL;
3865
3866 lxc_list_for_each_safe (it, list, next) {
3867 struct lxc_cgroup *cg = it->elem;
3868
3869 if (!all && strcmp(cg->subsystem, k) != 0)
3870 continue;
3871
3872 lxc_list_del(it);
3873 free(cg->subsystem);
3874 free(cg->value);
3875 free(cg);
3876 free(it);
3877 }
3878
3879 return 0;
3880 }
3881
3882 int lxc_clear_limits(struct lxc_conf *c, const char *key)
3883 {
3884 struct lxc_list *it, *next;
3885 const char *k = NULL;
3886 bool all = false;
3887
3888 if (strcmp(key, "lxc.limit") == 0 || strcmp(key, "lxc.prlimit") == 0)
3889 all = true;
3890 else if (strncmp(key, "lxc.limit.", STRLITERALLEN("lxc.limit.")) == 0)
3891 k = key + STRLITERALLEN("lxc.limit.");
3892 else if (strncmp(key, "lxc.prlimit.", STRLITERALLEN("lxc.prlimit.")) == 0)
3893 k = key + STRLITERALLEN("lxc.prlimit.");
3894 else
3895 return -1;
3896
3897 lxc_list_for_each_safe (it, &c->limits, next) {
3898 struct lxc_limit *lim = it->elem;
3899
3900 if (!all && strcmp(lim->resource, k) != 0)
3901 continue;
3902
3903 lxc_list_del(it);
3904 free(lim->resource);
3905 free(lim);
3906 free(it);
3907 }
3908
3909 return 0;
3910 }
3911
3912 int lxc_clear_sysctls(struct lxc_conf *c, const char *key)
3913 {
3914 struct lxc_list *it, *next;
3915 const char *k = NULL;
3916 bool all = false;
3917
3918 if (strcmp(key, "lxc.sysctl") == 0)
3919 all = true;
3920 else if (strncmp(key, "lxc.sysctl.", STRLITERALLEN("lxc.sysctl.")) == 0)
3921 k = key + STRLITERALLEN("lxc.sysctl.");
3922 else
3923 return -1;
3924
3925 lxc_list_for_each_safe (it, &c->sysctls, next) {
3926 struct lxc_sysctl *elem = it->elem;
3927
3928 if (!all && strcmp(elem->key, k) != 0)
3929 continue;
3930
3931 lxc_list_del(it);
3932 free(elem->key);
3933 free(elem->value);
3934 free(elem);
3935 free(it);
3936 }
3937
3938 return 0;
3939 }
3940
3941 int lxc_clear_procs(struct lxc_conf *c, const char *key)
3942 {
3943 struct lxc_list *it, *next;
3944 const char *k = NULL;
3945 bool all = false;
3946
3947 if (strcmp(key, "lxc.proc") == 0)
3948 all = true;
3949 else if (strncmp(key, "lxc.proc.", STRLITERALLEN("lxc.proc.")) == 0)
3950 k = key + STRLITERALLEN("lxc.proc.");
3951 else
3952 return -1;
3953
3954 lxc_list_for_each_safe (it, &c->procs, next) {
3955 struct lxc_proc *proc = it->elem;
3956
3957 if (!all && strcmp(proc->filename, k) != 0)
3958 continue;
3959
3960 lxc_list_del(it);
3961 free(proc->filename);
3962 free(proc->value);
3963 free(proc);
3964 free(it);
3965 }
3966
3967 return 0;
3968 }
3969
3970 int lxc_clear_groups(struct lxc_conf *c)
3971 {
3972 struct lxc_list *it, *next;
3973
3974 lxc_list_for_each_safe (it, &c->groups, next) {
3975 lxc_list_del(it);
3976 free(it->elem);
3977 free(it);
3978 }
3979
3980 return 0;
3981 }
3982
3983 int lxc_clear_environment(struct lxc_conf *c)
3984 {
3985 struct lxc_list *it, *next;
3986
3987 lxc_list_for_each_safe (it, &c->environment, next) {
3988 lxc_list_del(it);
3989 free(it->elem);
3990 free(it);
3991 }
3992
3993 return 0;
3994 }
3995
3996 int lxc_clear_mount_entries(struct lxc_conf *c)
3997 {
3998 struct lxc_list *it, *next;
3999
4000 lxc_list_for_each_safe (it, &c->mount_list, next) {
4001 lxc_list_del(it);
4002 free(it->elem);
4003 free(it);
4004 }
4005
4006 return 0;
4007 }
4008
4009 int lxc_clear_automounts(struct lxc_conf *c)
4010 {
4011 c->auto_mounts = 0;
4012 return 0;
4013 }
4014
4015 int lxc_clear_hooks(struct lxc_conf *c, const char *key)
4016 {
4017 int i;
4018 struct lxc_list *it, *next;
4019 const char *k = NULL;
4020 bool all = false, done = false;
4021
4022 if (strcmp(key, "lxc.hook") == 0)
4023 all = true;
4024 else if (strncmp(key, "lxc.hook.", STRLITERALLEN("lxc.hook.")) == 0)
4025 k = key + STRLITERALLEN("lxc.hook.");
4026 else
4027 return -1;
4028
4029 for (i = 0; i < NUM_LXC_HOOKS; i++) {
4030 if (all || strcmp(k, lxchook_names[i]) == 0) {
4031 lxc_list_for_each_safe (it, &c->hooks[i], next) {
4032 lxc_list_del(it);
4033 free(it->elem);
4034 free(it);
4035 }
4036
4037 done = true;
4038 }
4039 }
4040
4041 if (!done) {
4042 ERROR("Invalid hook key: %s", key);
4043 return -1;
4044 }
4045
4046 return 0;
4047 }
4048
4049 static inline void lxc_clear_aliens(struct lxc_conf *conf)
4050 {
4051 struct lxc_list *it, *next;
4052
4053 lxc_list_for_each_safe (it, &conf->aliens, next) {
4054 lxc_list_del(it);
4055 free(it->elem);
4056 free(it);
4057 }
4058 }
4059
4060 void lxc_clear_includes(struct lxc_conf *conf)
4061 {
4062 struct lxc_list *it, *next;
4063
4064 lxc_list_for_each_safe (it, &conf->includes, next) {
4065 lxc_list_del(it);
4066 free(it->elem);
4067 free(it);
4068 }
4069 }
4070
4071 int lxc_clear_apparmor_raw(struct lxc_conf *c)
4072 {
4073 struct lxc_list *it, *next;
4074
4075 lxc_list_for_each_safe (it, &c->lsm_aa_raw, next) {
4076 lxc_list_del(it);
4077 free(it->elem);
4078 free(it);
4079 }
4080
4081 return 0;
4082 }
4083
4084 void lxc_conf_free(struct lxc_conf *conf)
4085 {
4086 if (!conf)
4087 return;
4088
4089 if (current_config == conf)
4090 current_config = NULL;
4091 lxc_terminal_conf_free(&conf->console);
4092 free(conf->rootfs.mount);
4093 free(conf->rootfs.bdev_type);
4094 free(conf->rootfs.options);
4095 free(conf->rootfs.path);
4096 free(conf->logfile);
4097 if (conf->logfd != -1)
4098 close(conf->logfd);
4099 free(conf->utsname);
4100 free(conf->ttys.dir);
4101 free(conf->ttys.tty_names);
4102 free(conf->fstab);
4103 free(conf->rcfile);
4104 free(conf->execute_cmd);
4105 free(conf->init_cmd);
4106 free(conf->init_cwd);
4107 free(conf->unexpanded_config);
4108 free(conf->syslog);
4109 lxc_free_networks(&conf->network);
4110 free(conf->lsm_aa_profile);
4111 free(conf->lsm_aa_profile_computed);
4112 free(conf->lsm_se_context);
4113 lxc_seccomp_free(conf);
4114 lxc_clear_config_caps(conf);
4115 lxc_clear_config_keepcaps(conf);
4116 lxc_clear_cgroups(conf, "lxc.cgroup", CGROUP_SUPER_MAGIC);
4117 lxc_clear_cgroups(conf, "lxc.cgroup2", CGROUP2_SUPER_MAGIC);
4118 lxc_clear_hooks(conf, "lxc.hook");
4119 lxc_clear_mount_entries(conf);
4120 lxc_clear_idmaps(conf);
4121 lxc_clear_groups(conf);
4122 lxc_clear_includes(conf);
4123 lxc_clear_aliens(conf);
4124 lxc_clear_environment(conf);
4125 lxc_clear_limits(conf, "lxc.prlimit");
4126 lxc_clear_sysctls(conf, "lxc.sysctl");
4127 lxc_clear_procs(conf, "lxc.proc");
4128 lxc_clear_apparmor_raw(conf);
4129 free(conf->cgroup_meta.dir);
4130 free(conf->cgroup_meta.controllers);
4131 free(conf->shmount.path_host);
4132 free(conf->shmount.path_cont);
4133 free(conf);
4134 }
4135
4136 struct userns_fn_data {
4137 int (*fn)(void *);
4138 const char *fn_name;
4139 void *arg;
4140 int p[2];
4141 };
4142
4143 static int run_userns_fn(void *data)
4144 {
4145 int ret;
4146 char c;
4147 struct userns_fn_data *d = data;
4148
4149 /* Close write end of the pipe. */
4150 close(d->p[1]);
4151
4152 /* Wait for parent to finish establishing a new mapping in the user
4153 * namespace we are executing in.
4154 */
4155 ret = lxc_read_nointr(d->p[0], &c, 1);
4156 /* Close read end of the pipe. */
4157 close(d->p[0]);
4158 if (ret != 1)
4159 return -1;
4160
4161 if (d->fn_name)
4162 TRACE("Calling function \"%s\"", d->fn_name);
4163
4164 /* Call function to run. */
4165 return d->fn(d->arg);
4166 }
4167
4168 static struct id_map *mapped_nsid_add(struct lxc_conf *conf, unsigned id,
4169 enum idtype idtype)
4170 {
4171 const struct id_map *map;
4172 struct id_map *retmap;
4173
4174 map = find_mapped_nsid_entry(conf, id, idtype);
4175 if (!map)
4176 return NULL;
4177
4178 retmap = malloc(sizeof(*retmap));
4179 if (!retmap)
4180 return NULL;
4181
4182 memcpy(retmap, map, sizeof(*retmap));
4183 return retmap;
4184 }
4185
4186 static struct id_map *find_mapped_hostid_entry(struct lxc_conf *conf,
4187 unsigned id, enum idtype idtype)
4188 {
4189 struct id_map *map;
4190 struct lxc_list *it;
4191 struct id_map *retmap = NULL;
4192
4193 lxc_list_for_each (it, &conf->id_map) {
4194 map = it->elem;
4195 if (map->idtype != idtype)
4196 continue;
4197
4198 if (id >= map->hostid && id < map->hostid + map->range) {
4199 retmap = map;
4200 break;
4201 }
4202 }
4203
4204 return retmap;
4205 }
4206
4207 /* Allocate a new {g,u}id mapping for the given {g,u}id. Re-use an already
4208 * existing one or establish a new one.
4209 */
4210 static struct id_map *mapped_hostid_add(struct lxc_conf *conf, uid_t id,
4211 enum idtype type)
4212 {
4213 int hostid_mapped;
4214 struct id_map *entry = NULL, *tmp = NULL;
4215
4216 entry = malloc(sizeof(*entry));
4217 if (!entry)
4218 return NULL;
4219
4220 /* Reuse existing mapping. */
4221 tmp = find_mapped_hostid_entry(conf, id, type);
4222 if (tmp)
4223 return memcpy(entry, tmp, sizeof(*entry));
4224
4225 /* Find new mapping. */
4226 hostid_mapped = find_unmapped_nsid(conf, type);
4227 if (hostid_mapped < 0) {
4228 DEBUG("Failed to find free mapping for id %d", id);
4229 free(entry);
4230 return NULL;
4231 }
4232
4233 entry->idtype = type;
4234 entry->nsid = hostid_mapped;
4235 entry->hostid = (unsigned long)id;
4236 entry->range = 1;
4237
4238 return entry;
4239 }
4240
4241 struct lxc_list *get_minimal_idmap(struct lxc_conf *conf)
4242 {
4243 uid_t euid, egid;
4244 uid_t nsuid = (conf->root_nsuid_map != NULL) ? 0 : conf->init_uid;
4245 gid_t nsgid = (conf->root_nsgid_map != NULL) ? 0 : conf->init_gid;
4246 struct lxc_list *idmap = NULL, *tmplist = NULL;
4247 struct id_map *container_root_uid = NULL, *container_root_gid = NULL,
4248 *host_uid_map = NULL, *host_gid_map = NULL;
4249
4250 /* Find container root mappings. */
4251 container_root_uid = mapped_nsid_add(conf, nsuid, ID_TYPE_UID);
4252 if (!container_root_uid) {
4253 DEBUG("Failed to find mapping for namespace uid %d", 0);
4254 goto on_error;
4255 }
4256 euid = geteuid();
4257 if (euid >= container_root_uid->hostid &&
4258 euid < (container_root_uid->hostid + container_root_uid->range))
4259 host_uid_map = container_root_uid;
4260
4261 container_root_gid = mapped_nsid_add(conf, nsgid, ID_TYPE_GID);
4262 if (!container_root_gid) {
4263 DEBUG("Failed to find mapping for namespace gid %d", 0);
4264 goto on_error;
4265 }
4266 egid = getegid();
4267 if (egid >= container_root_gid->hostid &&
4268 egid < (container_root_gid->hostid + container_root_gid->range))
4269 host_gid_map = container_root_gid;
4270
4271 /* Check whether the {g,u}id of the user has a mapping. */
4272 if (!host_uid_map)
4273 host_uid_map = mapped_hostid_add(conf, euid, ID_TYPE_UID);
4274 if (!host_uid_map) {
4275 DEBUG("Failed to find mapping for uid %d", euid);
4276 goto on_error;
4277 }
4278
4279 if (!host_gid_map)
4280 host_gid_map = mapped_hostid_add(conf, egid, ID_TYPE_GID);
4281 if (!host_gid_map) {
4282 DEBUG("Failed to find mapping for gid %d", egid);
4283 goto on_error;
4284 }
4285
4286 /* Allocate new {g,u}id map list. */
4287 idmap = malloc(sizeof(*idmap));
4288 if (!idmap)
4289 goto on_error;
4290 lxc_list_init(idmap);
4291
4292 /* Add container root to the map. */
4293 tmplist = malloc(sizeof(*tmplist));
4294 if (!tmplist)
4295 goto on_error;
4296 lxc_list_add_elem(tmplist, container_root_uid);
4297 lxc_list_add_tail(idmap, tmplist);
4298
4299 if (host_uid_map && (host_uid_map != container_root_uid)) {
4300 /* idmap will now keep track of that memory. */
4301 container_root_uid = NULL;
4302
4303 /* Add container root to the map. */
4304 tmplist = malloc(sizeof(*tmplist));
4305 if (!tmplist)
4306 goto on_error;
4307 lxc_list_add_elem(tmplist, host_uid_map);
4308 lxc_list_add_tail(idmap, tmplist);
4309 }
4310 /* idmap will now keep track of that memory. */
4311 container_root_uid = NULL;
4312 /* idmap will now keep track of that memory. */
4313 host_uid_map = NULL;
4314
4315 tmplist = malloc(sizeof(*tmplist));
4316 if (!tmplist)
4317 goto on_error;
4318 lxc_list_add_elem(tmplist, container_root_gid);
4319 lxc_list_add_tail(idmap, tmplist);
4320
4321 if (host_gid_map && (host_gid_map != container_root_gid)) {
4322 /* idmap will now keep track of that memory. */
4323 container_root_gid = NULL;
4324
4325 tmplist = malloc(sizeof(*tmplist));
4326 if (!tmplist)
4327 goto on_error;
4328 lxc_list_add_elem(tmplist, host_gid_map);
4329 lxc_list_add_tail(idmap, tmplist);
4330 }
4331 /* idmap will now keep track of that memory. */
4332 container_root_gid = NULL;
4333 /* idmap will now keep track of that memory. */
4334 host_gid_map = NULL;
4335
4336 TRACE("Allocated minimal idmapping");
4337 return idmap;
4338
4339 on_error:
4340 if (idmap) {
4341 lxc_free_idmap(idmap);
4342 free(idmap);
4343 }
4344 if (container_root_uid)
4345 free(container_root_uid);
4346 if (container_root_gid)
4347 free(container_root_gid);
4348 if (host_uid_map && (host_uid_map != container_root_uid))
4349 free(host_uid_map);
4350 if (host_gid_map && (host_gid_map != container_root_gid))
4351 free(host_gid_map);
4352
4353 return NULL;
4354 }
4355
4356 /* Run a function in a new user namespace.
4357 * The caller's euid/egid will be mapped if it is not already.
4358 * Afaict, userns_exec_1() is only used to operate based on privileges for the
4359 * user's own {g,u}id on the host and for the container root's unmapped {g,u}id.
4360 * This means we require only to establish a mapping from:
4361 * - the container root {g,u}id as seen from the host > user's host {g,u}id
4362 * - the container root -> some sub{g,u}id
4363 * The former we add, if the user did not specify a mapping. The latter we
4364 * retrieve from the container's configured {g,u}id mappings as it must have been
4365 * there to start the container in the first place.
4366 */
4367 int userns_exec_1(struct lxc_conf *conf, int (*fn)(void *), void *data,
4368 const char *fn_name)
4369 {
4370 pid_t pid;
4371 int p[2];
4372 struct userns_fn_data d;
4373 struct lxc_list *idmap;
4374 int ret = -1, status = -1;
4375 char c = '1';
4376
4377 if (!conf)
4378 return -EINVAL;
4379
4380 idmap = get_minimal_idmap(conf);
4381 if (!idmap)
4382 return -1;
4383
4384 ret = pipe2(p, O_CLOEXEC);
4385 if (ret < 0) {
4386 SYSERROR("Failed to create pipe");
4387 return -1;
4388 }
4389 d.fn = fn;
4390 d.fn_name = fn_name;
4391 d.arg = data;
4392 d.p[0] = p[0];
4393 d.p[1] = p[1];
4394
4395 /* Clone child in new user namespace. */
4396 pid = lxc_raw_clone_cb(run_userns_fn, &d, CLONE_NEWUSER);
4397 if (pid < 0) {
4398 ERROR("Failed to clone process in new user namespace");
4399 goto on_error;
4400 }
4401
4402 close(p[0]);
4403 p[0] = -1;
4404
4405 if (lxc_log_get_level() == LXC_LOG_LEVEL_TRACE ||
4406 conf->loglevel == LXC_LOG_LEVEL_TRACE) {
4407 struct id_map *map;
4408 struct lxc_list *it;
4409
4410 lxc_list_for_each (it, idmap) {
4411 map = it->elem;
4412 TRACE("Establishing %cid mapping for \"%d\" in new "
4413 "user namespace: nsuid %lu - hostid %lu - range "
4414 "%lu",
4415 (map->idtype == ID_TYPE_UID) ? 'u' : 'g', pid,
4416 map->nsid, map->hostid, map->range);
4417 }
4418 }
4419
4420 /* Set up {g,u}id mapping for user namespace of child process. */
4421 ret = lxc_map_ids(idmap, pid);
4422 if (ret < 0) {
4423 ERROR("Error setting up {g,u}id mappings for child process \"%d\"", pid);
4424 goto on_error;
4425 }
4426
4427 /* Tell child to proceed. */
4428 if (lxc_write_nointr(p[1], &c, 1) != 1) {
4429 SYSERROR("Failed telling child process \"%d\" to proceed", pid);
4430 goto on_error;
4431 }
4432
4433 on_error:
4434 if (p[0] != -1)
4435 close(p[0]);
4436 close(p[1]);
4437
4438 /* Wait for child to finish. */
4439 if (pid > 0)
4440 status = wait_for_pid(pid);
4441
4442 if (status < 0)
4443 ret = -1;
4444
4445 return ret;
4446 }
4447
4448 int userns_exec_full(struct lxc_conf *conf, int (*fn)(void *), void *data,
4449 const char *fn_name)
4450 {
4451 pid_t pid;
4452 uid_t euid, egid;
4453 int p[2];
4454 struct id_map *map;
4455 struct lxc_list *cur;
4456 struct userns_fn_data d;
4457 int ret = -1;
4458 char c = '1';
4459 struct lxc_list *idmap = NULL, *tmplist = NULL;
4460 struct id_map *container_root_uid = NULL, *container_root_gid = NULL,
4461 *host_uid_map = NULL, *host_gid_map = NULL;
4462
4463 if (!conf)
4464 return -EINVAL;
4465
4466 ret = pipe2(p, O_CLOEXEC);
4467 if (ret < 0) {
4468 SYSERROR("opening pipe");
4469 return -1;
4470 }
4471 d.fn = fn;
4472 d.fn_name = fn_name;
4473 d.arg = data;
4474 d.p[0] = p[0];
4475 d.p[1] = p[1];
4476
4477 /* Clone child in new user namespace. */
4478 pid = lxc_clone(run_userns_fn, &d, CLONE_NEWUSER);
4479 if (pid < 0) {
4480 ERROR("Failed to clone process in new user namespace");
4481 goto on_error;
4482 }
4483
4484 close(p[0]);
4485 p[0] = -1;
4486
4487 euid = geteuid();
4488 egid = getegid();
4489
4490 /* Allocate new {g,u}id map list. */
4491 idmap = malloc(sizeof(*idmap));
4492 if (!idmap)
4493 goto on_error;
4494 lxc_list_init(idmap);
4495
4496 /* Find container root. */
4497 lxc_list_for_each (cur, &conf->id_map) {
4498 struct id_map *tmpmap;
4499
4500 tmplist = malloc(sizeof(*tmplist));
4501 if (!tmplist)
4502 goto on_error;
4503
4504 tmpmap = malloc(sizeof(*tmpmap));
4505 if (!tmpmap) {
4506 free(tmplist);
4507 goto on_error;
4508 }
4509
4510 memset(tmpmap, 0, sizeof(*tmpmap));
4511 memcpy(tmpmap, cur->elem, sizeof(*tmpmap));
4512 tmplist->elem = tmpmap;
4513
4514 lxc_list_add_tail(idmap, tmplist);
4515
4516 map = cur->elem;
4517
4518 if (map->idtype == ID_TYPE_UID)
4519 if (euid >= map->hostid && euid < map->hostid + map->range)
4520 host_uid_map = map;
4521
4522 if (map->idtype == ID_TYPE_GID)
4523 if (egid >= map->hostid && egid < map->hostid + map->range)
4524 host_gid_map = map;
4525
4526 if (map->nsid != 0)
4527 continue;
4528
4529 if (map->idtype == ID_TYPE_UID)
4530 if (container_root_uid == NULL)
4531 container_root_uid = map;
4532
4533 if (map->idtype == ID_TYPE_GID)
4534 if (container_root_gid == NULL)
4535 container_root_gid = map;
4536 }
4537
4538 if (!container_root_uid || !container_root_gid) {
4539 ERROR("No mapping for container root found");
4540 goto on_error;
4541 }
4542
4543 /* Check whether the {g,u}id of the user has a mapping. */
4544 if (!host_uid_map)
4545 host_uid_map = mapped_hostid_add(conf, euid, ID_TYPE_UID);
4546 else
4547 host_uid_map = container_root_uid;
4548
4549 if (!host_gid_map)
4550 host_gid_map = mapped_hostid_add(conf, egid, ID_TYPE_GID);
4551 else
4552 host_gid_map = container_root_gid;
4553
4554 if (!host_uid_map) {
4555 DEBUG("Failed to find mapping for uid %d", euid);
4556 goto on_error;
4557 }
4558
4559 if (!host_gid_map) {
4560 DEBUG("Failed to find mapping for gid %d", egid);
4561 goto on_error;
4562 }
4563
4564 if (host_uid_map && (host_uid_map != container_root_uid)) {
4565 /* Add container root to the map. */
4566 tmplist = malloc(sizeof(*tmplist));
4567 if (!tmplist)
4568 goto on_error;
4569 lxc_list_add_elem(tmplist, host_uid_map);
4570 lxc_list_add_tail(idmap, tmplist);
4571 }
4572 /* idmap will now keep track of that memory. */
4573 host_uid_map = NULL;
4574
4575 if (host_gid_map && (host_gid_map != container_root_gid)) {
4576 tmplist = malloc(sizeof(*tmplist));
4577 if (!tmplist)
4578 goto on_error;
4579 lxc_list_add_elem(tmplist, host_gid_map);
4580 lxc_list_add_tail(idmap, tmplist);
4581 }
4582 /* idmap will now keep track of that memory. */
4583 host_gid_map = NULL;
4584
4585 if (lxc_log_get_level() == LXC_LOG_LEVEL_TRACE ||
4586 conf->loglevel == LXC_LOG_LEVEL_TRACE) {
4587 lxc_list_for_each (cur, idmap) {
4588 map = cur->elem;
4589 TRACE("establishing %cid mapping for \"%d\" in new "
4590 "user namespace: nsuid %lu - hostid %lu - range "
4591 "%lu",
4592 (map->idtype == ID_TYPE_UID) ? 'u' : 'g', pid,
4593 map->nsid, map->hostid, map->range);
4594 }
4595 }
4596
4597 /* Set up {g,u}id mapping for user namespace of child process. */
4598 ret = lxc_map_ids(idmap, pid);
4599 if (ret < 0) {
4600 ERROR("error setting up {g,u}id mappings for child process \"%d\"", pid);
4601 goto on_error;
4602 }
4603
4604 /* Tell child to proceed. */
4605 if (lxc_write_nointr(p[1], &c, 1) != 1) {
4606 SYSERROR("Failed telling child process \"%d\" to proceed", pid);
4607 goto on_error;
4608 }
4609
4610 on_error:
4611 if (p[0] != -1)
4612 close(p[0]);
4613 close(p[1]);
4614
4615 /* Wait for child to finish. */
4616 if (pid > 0)
4617 ret = wait_for_pid(pid);
4618
4619 if (idmap) {
4620 lxc_free_idmap(idmap);
4621 free(idmap);
4622 }
4623
4624 if (host_uid_map && (host_uid_map != container_root_uid))
4625 free(host_uid_map);
4626 if (host_gid_map && (host_gid_map != container_root_gid))
4627 free(host_gid_map);
4628
4629 return ret;
4630 }
4631
4632 /* not thread-safe, do not use from api without first forking */
4633 static char *getuname(void)
4634 {
4635 struct passwd pwent;
4636 struct passwd *pwentp = NULL;
4637 char *buf;
4638 char *username;
4639 size_t bufsize;
4640 int ret;
4641
4642 bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
4643 if (bufsize == -1)
4644 bufsize = 1024;
4645
4646 buf = malloc(bufsize);
4647 if (!buf)
4648 return NULL;
4649
4650 ret = getpwuid_r(geteuid(), &pwent, buf, bufsize, &pwentp);
4651 if (!pwentp) {
4652 if (ret == 0)
4653 WARN("Could not find matched password record.");
4654
4655 ERROR("Failed to get password record - %u", geteuid());
4656 free(buf);
4657 return NULL;
4658 }
4659
4660 username = strdup(pwent.pw_name);
4661 free(buf);
4662
4663 return username;
4664 }
4665
4666 /* not thread-safe, do not use from api without first forking */
4667 static char *getgname(void)
4668 {
4669 struct group grent;
4670 struct group *grentp = NULL;
4671 char *buf;
4672 char *grname;
4673 size_t bufsize;
4674 int ret;
4675
4676 bufsize = sysconf(_SC_GETGR_R_SIZE_MAX);
4677 if (bufsize == -1)
4678 bufsize = 1024;
4679
4680 buf = malloc(bufsize);
4681 if (!buf)
4682 return NULL;
4683
4684 ret = getgrgid_r(getegid(), &grent, buf, bufsize, &grentp);
4685 if (!grentp) {
4686 if (ret == 0)
4687 WARN("Could not find matched group record");
4688
4689 ERROR("Failed to get group record - %u", getegid());
4690 free(buf);
4691 return NULL;
4692 }
4693
4694 grname = strdup(grent.gr_name);
4695 free(buf);
4696
4697 return grname;
4698 }
4699
4700 /* not thread-safe, do not use from api without first forking */
4701 void suggest_default_idmap(void)
4702 {
4703 char *uname, *gname;
4704 FILE *f;
4705 unsigned int uid = 0, urange = 0, gid = 0, grange = 0;
4706 size_t len = 0;
4707 char *line = NULL;
4708
4709 uname = getuname();
4710 if (!uname)
4711 return;
4712
4713 gname = getgname();
4714 if (!gname) {
4715 free(uname);
4716 return;
4717 }
4718
4719 f = fopen(subuidfile, "r");
4720 if (!f) {
4721 ERROR("Your system is not configured with subuids");
4722 free(gname);
4723 free(uname);
4724 return;
4725 }
4726
4727 while (getline(&line, &len, f) != -1) {
4728 char *p, *p2;
4729 size_t no_newline = 0;
4730
4731 p = strchr(line, ':');
4732 if (*line == '#')
4733 continue;
4734 if (!p)
4735 continue;
4736 *p = '\0';
4737 p++;
4738
4739 if (strcmp(line, uname))
4740 continue;
4741
4742 p2 = strchr(p, ':');
4743 if (!p2)
4744 continue;
4745 *p2 = '\0';
4746 p2++;
4747 if (!*p2)
4748 continue;
4749 no_newline = strcspn(p2, "\n");
4750 p2[no_newline] = '\0';
4751
4752 if (lxc_safe_uint(p, &uid) < 0)
4753 WARN("Could not parse UID");
4754 if (lxc_safe_uint(p2, &urange) < 0)
4755 WARN("Could not parse UID range");
4756 }
4757 fclose(f);
4758
4759 f = fopen(subgidfile, "r");
4760 if (!f) {
4761 ERROR("Your system is not configured with subgids");
4762 free(gname);
4763 free(uname);
4764 return;
4765 }
4766
4767 while (getline(&line, &len, f) != -1) {
4768 char *p, *p2;
4769 size_t no_newline = 0;
4770
4771 p = strchr(line, ':');
4772 if (*line == '#')
4773 continue;
4774 if (!p)
4775 continue;
4776 *p = '\0';
4777 p++;
4778
4779 if (strcmp(line, uname))
4780 continue;
4781
4782 p2 = strchr(p, ':');
4783 if (!p2)
4784 continue;
4785 *p2 = '\0';
4786 p2++;
4787 if (!*p2)
4788 continue;
4789 no_newline = strcspn(p2, "\n");
4790 p2[no_newline] = '\0';
4791
4792 if (lxc_safe_uint(p, &gid) < 0)
4793 WARN("Could not parse GID");
4794 if (lxc_safe_uint(p2, &grange) < 0)
4795 WARN("Could not parse GID range");
4796 }
4797 fclose(f);
4798
4799 free(line);
4800
4801 if (!urange || !grange) {
4802 ERROR("You do not have subuids or subgids allocated");
4803 ERROR("Unprivileged containers require subuids and subgids");
4804 free(uname);
4805 free(gname);
4806 return;
4807 }
4808
4809 ERROR("You must either run as root, or define uid mappings");
4810 ERROR("To pass uid mappings to lxc-create, you could create");
4811 ERROR("~/.config/lxc/default.conf:");
4812 ERROR("lxc.include = %s", LXC_DEFAULT_CONFIG);
4813 ERROR("lxc.idmap = u 0 %u %u", uid, urange);
4814 ERROR("lxc.idmap = g 0 %u %u", gid, grange);
4815
4816 free(gname);
4817 free(uname);
4818 }
4819
4820 static void free_cgroup_settings(struct lxc_list *result)
4821 {
4822 struct lxc_list *iterator, *next;
4823
4824 lxc_list_for_each_safe (iterator, result, next) {
4825 lxc_list_del(iterator);
4826 free(iterator);
4827 }
4828 free(result);
4829 }
4830
4831 /* Return the list of cgroup_settings sorted according to the following rules
4832 * 1. Put memory.limit_in_bytes before memory.memsw.limit_in_bytes
4833 */
4834 struct lxc_list *sort_cgroup_settings(struct lxc_list *cgroup_settings)
4835 {
4836 struct lxc_list *result;
4837 struct lxc_cgroup *cg = NULL;
4838 struct lxc_list *it = NULL, *item = NULL, *memsw_limit = NULL;
4839
4840 result = malloc(sizeof(*result));
4841 if (!result)
4842 return NULL;
4843 lxc_list_init(result);
4844
4845 /* Iterate over the cgroup settings and copy them to the output list. */
4846 lxc_list_for_each (it, cgroup_settings) {
4847 item = malloc(sizeof(*item));
4848 if (!item) {
4849 free_cgroup_settings(result);
4850 return NULL;
4851 }
4852
4853 item->elem = it->elem;
4854 cg = it->elem;
4855 if (strcmp(cg->subsystem, "memory.memsw.limit_in_bytes") == 0) {
4856 /* Store the memsw_limit location */
4857 memsw_limit = item;
4858 } else if (strcmp(cg->subsystem, "memory.limit_in_bytes") == 0 &&
4859 memsw_limit != NULL) {
4860 /* lxc.cgroup.memory.memsw.limit_in_bytes is found
4861 * before lxc.cgroup.memory.limit_in_bytes, swap these
4862 * two items */
4863 item->elem = memsw_limit->elem;
4864 memsw_limit->elem = it->elem;
4865 }
4866 lxc_list_add_tail(result, item);
4867 }
4868
4869 return result;
4870 }
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