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Merge pull request #2886 from brauner/2019-03-01/bugfixes
[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 "memory_utils.h"
71 #include "namespace.h"
72 #include "network.h"
73 #include "parse.h"
74 #include "raw_syscalls.h"
75 #include "ringbuf.h"
76 #include "start.h"
77 #include "storage.h"
78 #include "storage/overlay.h"
79 #include "syscall_wrappers.h"
80 #include "terminal.h"
81 #include "utils.h"
82
83 #ifdef MAJOR_IN_MKDEV
84 #include <sys/mkdev.h>
85 #endif
86
87 #ifdef HAVE_STATVFS
88 #include <sys/statvfs.h>
89 #endif
90
91 #if HAVE_PTY_H
92 #include <pty.h>
93 #else
94 #include <../include/openpty.h>
95 #endif
96
97 #if HAVE_LIBCAP
98 #include <sys/capability.h>
99 #endif
100
101 #if HAVE_SYS_PERSONALITY_H
102 #include <sys/personality.h>
103 #endif
104
105 #ifndef HAVE_STRLCAT
106 #include "include/strlcat.h"
107 #endif
108
109 #if IS_BIONIC
110 #include <../include/lxcmntent.h>
111 #else
112 #include <mntent.h>
113 #endif
114
115 #if !defined(HAVE_PRLIMIT) && defined(HAVE_PRLIMIT64)
116 #include <../include/prlimit.h>
117 #endif
118
119 lxc_log_define(conf, lxc);
120
121 /* The lxc_conf of the container currently being worked on in an API call.
122 * This is used in the error calls.
123 */
124 #ifdef HAVE_TLS
125 thread_local struct lxc_conf *current_config;
126 #else
127 struct lxc_conf *current_config;
128 #endif
129
130 char *lxchook_names[NUM_LXC_HOOKS] = {
131 "pre-start",
132 "pre-mount",
133 "mount",
134 "autodev",
135 "start",
136 "stop",
137 "post-stop",
138 "clone",
139 "destroy",
140 "start-host"
141 };
142
143 struct mount_opt {
144 char *name;
145 int clear;
146 int flag;
147 };
148
149 struct caps_opt {
150 char *name;
151 int value;
152 };
153
154 struct limit_opt {
155 char *name;
156 int value;
157 };
158
159 static struct mount_opt mount_opt[] = {
160 { "async", 1, MS_SYNCHRONOUS },
161 { "atime", 1, MS_NOATIME },
162 { "bind", 0, MS_BIND },
163 { "defaults", 0, 0 },
164 { "dev", 1, MS_NODEV },
165 { "diratime", 1, MS_NODIRATIME },
166 { "dirsync", 0, MS_DIRSYNC },
167 { "exec", 1, MS_NOEXEC },
168 { "lazytime", 0, MS_LAZYTIME },
169 { "mand", 0, MS_MANDLOCK },
170 { "noatime", 0, MS_NOATIME },
171 { "nodev", 0, MS_NODEV },
172 { "nodiratime", 0, MS_NODIRATIME },
173 { "noexec", 0, MS_NOEXEC },
174 { "nomand", 1, MS_MANDLOCK },
175 { "norelatime", 1, MS_RELATIME },
176 { "nostrictatime", 1, MS_STRICTATIME },
177 { "nosuid", 0, MS_NOSUID },
178 { "rbind", 0, MS_BIND|MS_REC },
179 { "relatime", 0, MS_RELATIME },
180 { "remount", 0, MS_REMOUNT },
181 { "ro", 0, MS_RDONLY },
182 { "rw", 1, MS_RDONLY },
183 { "strictatime", 0, MS_STRICTATIME },
184 { "suid", 1, MS_NOSUID },
185 { "sync", 0, MS_SYNCHRONOUS },
186 { NULL, 0, 0 },
187 };
188
189 static struct mount_opt propagation_opt[] = {
190 { "private", 0, MS_PRIVATE },
191 { "shared", 0, MS_SHARED },
192 { "slave", 0, MS_SLAVE },
193 { "unbindable", 0, MS_UNBINDABLE },
194 { "rprivate", 0, MS_PRIVATE|MS_REC },
195 { "rshared", 0, MS_SHARED|MS_REC },
196 { "rslave", 0, MS_SLAVE|MS_REC },
197 { "runbindable", 0, MS_UNBINDABLE|MS_REC },
198 { NULL, 0, 0 },
199 };
200
201 static struct caps_opt caps_opt[] = {
202 #if HAVE_LIBCAP
203 { "chown", CAP_CHOWN },
204 { "dac_override", CAP_DAC_OVERRIDE },
205 { "dac_read_search", CAP_DAC_READ_SEARCH },
206 { "fowner", CAP_FOWNER },
207 { "fsetid", CAP_FSETID },
208 { "kill", CAP_KILL },
209 { "setgid", CAP_SETGID },
210 { "setuid", CAP_SETUID },
211 { "setpcap", CAP_SETPCAP },
212 { "linux_immutable", CAP_LINUX_IMMUTABLE },
213 { "net_bind_service", CAP_NET_BIND_SERVICE },
214 { "net_broadcast", CAP_NET_BROADCAST },
215 { "net_admin", CAP_NET_ADMIN },
216 { "net_raw", CAP_NET_RAW },
217 { "ipc_lock", CAP_IPC_LOCK },
218 { "ipc_owner", CAP_IPC_OWNER },
219 { "sys_module", CAP_SYS_MODULE },
220 { "sys_rawio", CAP_SYS_RAWIO },
221 { "sys_chroot", CAP_SYS_CHROOT },
222 { "sys_ptrace", CAP_SYS_PTRACE },
223 { "sys_pacct", CAP_SYS_PACCT },
224 { "sys_admin", CAP_SYS_ADMIN },
225 { "sys_boot", CAP_SYS_BOOT },
226 { "sys_nice", CAP_SYS_NICE },
227 { "sys_resource", CAP_SYS_RESOURCE },
228 { "sys_time", CAP_SYS_TIME },
229 { "sys_tty_config", CAP_SYS_TTY_CONFIG },
230 { "mknod", CAP_MKNOD },
231 { "lease", CAP_LEASE },
232 #ifdef CAP_AUDIT_READ
233 { "audit_read", CAP_AUDIT_READ },
234 #endif
235 #ifdef CAP_AUDIT_WRITE
236 { "audit_write", CAP_AUDIT_WRITE },
237 #endif
238 #ifdef CAP_AUDIT_CONTROL
239 { "audit_control", CAP_AUDIT_CONTROL },
240 #endif
241 { "setfcap", CAP_SETFCAP },
242 { "mac_override", CAP_MAC_OVERRIDE },
243 { "mac_admin", CAP_MAC_ADMIN },
244 #ifdef CAP_SYSLOG
245 { "syslog", CAP_SYSLOG },
246 #endif
247 #ifdef CAP_WAKE_ALARM
248 { "wake_alarm", CAP_WAKE_ALARM },
249 #endif
250 #ifdef CAP_BLOCK_SUSPEND
251 { "block_suspend", CAP_BLOCK_SUSPEND },
252 #endif
253 #endif
254 };
255
256 static struct limit_opt limit_opt[] = {
257 #ifdef RLIMIT_AS
258 { "as", RLIMIT_AS },
259 #endif
260 #ifdef RLIMIT_CORE
261 { "core", RLIMIT_CORE },
262 #endif
263 #ifdef RLIMIT_CPU
264 { "cpu", RLIMIT_CPU },
265 #endif
266 #ifdef RLIMIT_DATA
267 { "data", RLIMIT_DATA },
268 #endif
269 #ifdef RLIMIT_FSIZE
270 { "fsize", RLIMIT_FSIZE },
271 #endif
272 #ifdef RLIMIT_LOCKS
273 { "locks", RLIMIT_LOCKS },
274 #endif
275 #ifdef RLIMIT_MEMLOCK
276 { "memlock", RLIMIT_MEMLOCK },
277 #endif
278 #ifdef RLIMIT_MSGQUEUE
279 { "msgqueue", RLIMIT_MSGQUEUE },
280 #endif
281 #ifdef RLIMIT_NICE
282 { "nice", RLIMIT_NICE },
283 #endif
284 #ifdef RLIMIT_NOFILE
285 { "nofile", RLIMIT_NOFILE },
286 #endif
287 #ifdef RLIMIT_NPROC
288 { "nproc", RLIMIT_NPROC },
289 #endif
290 #ifdef RLIMIT_RSS
291 { "rss", RLIMIT_RSS },
292 #endif
293 #ifdef RLIMIT_RTPRIO
294 { "rtprio", RLIMIT_RTPRIO },
295 #endif
296 #ifdef RLIMIT_RTTIME
297 { "rttime", RLIMIT_RTTIME },
298 #endif
299 #ifdef RLIMIT_SIGPENDING
300 { "sigpending", RLIMIT_SIGPENDING },
301 #endif
302 #ifdef RLIMIT_STACK
303 { "stack", RLIMIT_STACK },
304 #endif
305 };
306
307 static int run_buffer(char *buffer)
308 {
309 __do_free char *output = NULL;
310 int ret;
311 struct lxc_popen_FILE *f;
312
313 f = lxc_popen(buffer);
314 if (!f) {
315 SYSERROR("Failed to popen() %s", buffer);
316 return -1;
317 }
318
319 output = malloc(LXC_LOG_BUFFER_SIZE);
320 if (!output) {
321 ERROR("Failed to allocate memory for %s", buffer);
322 lxc_pclose(f);
323 return -1;
324 }
325
326 while (fgets(output, LXC_LOG_BUFFER_SIZE, f->f))
327 DEBUG("Script %s with output: %s", buffer, output);
328
329 ret = lxc_pclose(f);
330 if (ret == -1) {
331 SYSERROR("Script exited with error");
332 return -1;
333 } else if (WIFEXITED(ret) && WEXITSTATUS(ret) != 0) {
334 ERROR("Script exited with status %d", WEXITSTATUS(ret));
335 return -1;
336 } else if (WIFSIGNALED(ret)) {
337 ERROR("Script terminated by signal %d", WTERMSIG(ret));
338 return -1;
339 }
340
341 return 0;
342 }
343
344 int run_script_argv(const char *name, unsigned int hook_version,
345 const char *section, const char *script,
346 const char *hookname, char **argv)
347 {
348 __do_free char *buffer = NULL;
349 int buf_pos, i, ret;
350 size_t size = 0;
351
352 if (hook_version == 0)
353 INFO("Executing script \"%s\" for container \"%s\", config "
354 "section \"%s\"", script, name, section);
355 else
356 INFO("Executing script \"%s\" for container \"%s\"", script, name);
357
358 for (i = 0; argv && argv[i]; i++)
359 size += strlen(argv[i]) + 1;
360
361 size += STRLITERALLEN("exec");
362 size++;
363 size += strlen(script);
364 size++;
365
366 if (size > INT_MAX)
367 return -EFBIG;
368
369 if (hook_version == 0) {
370 size += strlen(hookname);
371 size++;
372
373 size += strlen(name);
374 size++;
375
376 size += strlen(section);
377 size++;
378
379 if (size > INT_MAX)
380 return -EFBIG;
381 }
382
383 buffer = malloc(size);
384 if (!buffer)
385 return -ENOMEM;
386
387 if (hook_version == 0)
388 buf_pos = snprintf(buffer, size, "exec %s %s %s %s", script, name, section, hookname);
389 else
390 buf_pos = snprintf(buffer, size, "exec %s", script);
391 if (buf_pos < 0 || (size_t)buf_pos >= size) {
392 ERROR("Failed to create command line for script \"%s\"", script);
393 return -1;
394 }
395
396 if (hook_version == 1) {
397 ret = setenv("LXC_HOOK_TYPE", hookname, 1);
398 if (ret < 0) {
399 SYSERROR("Failed to set environment variable: "
400 "LXC_HOOK_TYPE=%s", hookname);
401 return -1;
402 }
403 TRACE("Set environment variable: LXC_HOOK_TYPE=%s", hookname);
404
405 ret = setenv("LXC_HOOK_SECTION", section, 1);
406 if (ret < 0) {
407 SYSERROR("Failed to set environment variable: "
408 "LXC_HOOK_SECTION=%s", section);
409 return -1;
410 }
411 TRACE("Set environment variable: LXC_HOOK_SECTION=%s", section);
412
413 if (strcmp(section, "net") == 0) {
414 char *parent;
415
416 if (!argv || !argv[0])
417 return -1;
418
419 ret = setenv("LXC_NET_TYPE", argv[0], 1);
420 if (ret < 0) {
421 SYSERROR("Failed to set environment variable: "
422 "LXC_NET_TYPE=%s", argv[0]);
423 return -1;
424 }
425 TRACE("Set environment variable: LXC_NET_TYPE=%s", argv[0]);
426
427 parent = argv[1] ? argv[1] : "";
428
429 if (strcmp(argv[0], "macvlan") == 0) {
430 ret = setenv("LXC_NET_PARENT", parent, 1);
431 if (ret < 0) {
432 SYSERROR("Failed to set environment "
433 "variable: LXC_NET_PARENT=%s", parent);
434 return -1;
435 }
436 TRACE("Set environment variable: LXC_NET_PARENT=%s", parent);
437 } else if (strcmp(argv[0], "phys") == 0) {
438 ret = setenv("LXC_NET_PARENT", parent, 1);
439 if (ret < 0) {
440 SYSERROR("Failed to set environment "
441 "variable: LXC_NET_PARENT=%s", parent);
442 return -1;
443 }
444 TRACE("Set environment variable: LXC_NET_PARENT=%s", parent);
445 } else if (strcmp(argv[0], "veth") == 0) {
446 char *peer = argv[2] ? argv[2] : "";
447
448 ret = setenv("LXC_NET_PEER", peer, 1);
449 if (ret < 0) {
450 SYSERROR("Failed to set environment "
451 "variable: LXC_NET_PEER=%s", peer);
452 return -1;
453 }
454 TRACE("Set environment variable: LXC_NET_PEER=%s", peer);
455
456 ret = setenv("LXC_NET_PARENT", parent, 1);
457 if (ret < 0) {
458 SYSERROR("Failed to set environment "
459 "variable: LXC_NET_PARENT=%s", parent);
460 return -1;
461 }
462 TRACE("Set environment variable: LXC_NET_PARENT=%s", parent);
463 }
464 }
465 }
466
467 for (i = 0; argv && argv[i]; i++) {
468 size_t len = size - buf_pos;
469
470 ret = snprintf(buffer + buf_pos, len, " %s", argv[i]);
471 if (ret < 0 || (size_t)ret >= len) {
472 ERROR("Failed to create command line for script \"%s\"", script);
473 return -1;
474 }
475 buf_pos += ret;
476 }
477
478 return run_buffer(buffer);
479 }
480
481 int run_script(const char *name, const char *section, const char *script, ...)
482 {
483 __do_free char *buffer = NULL;
484 int ret;
485 char *p;
486 va_list ap;
487 size_t size = 0;
488
489 INFO("Executing script \"%s\" for container \"%s\", config section \"%s\"",
490 script, name, section);
491
492 va_start(ap, script);
493 while ((p = va_arg(ap, char *)))
494 size += strlen(p) + 1;
495 va_end(ap);
496
497 size += STRLITERALLEN("exec");
498 size += strlen(script);
499 size += strlen(name);
500 size += strlen(section);
501 size += 4;
502
503 if (size > INT_MAX)
504 return -1;
505
506 buffer = must_realloc(NULL, size);
507 ret = snprintf(buffer, size, "exec %s %s %s", script, name, section);
508 if (ret < 0 || ret >= size)
509 return -1;
510
511 va_start(ap, script);
512 while ((p = va_arg(ap, char *))) {
513 int len = size - ret;
514 int rc;
515 rc = snprintf(buffer + ret, len, " %s", p);
516 if (rc < 0 || rc >= len) {
517 va_end(ap);
518 return -1;
519 }
520 ret += rc;
521 }
522 va_end(ap);
523
524 return run_buffer(buffer);
525 }
526
527 /* pin_rootfs
528 * if rootfs is a directory, then open ${rootfs}/.lxc-keep for writing for
529 * the duration of the container run, to prevent the container from marking
530 * the underlying fs readonly on shutdown. unlink the file immediately so
531 * no name pollution is happens.
532 * don't unlink on NFS to avoid random named stale handles.
533 * return -1 on error.
534 * return -2 if nothing needed to be pinned.
535 * return an open fd (>=0) if we pinned it.
536 */
537 int pin_rootfs(const char *rootfs)
538 {
539 __do_free char *absrootfs = NULL;
540 int fd, ret;
541 char absrootfspin[PATH_MAX];
542 struct stat s;
543 struct statfs sfs;
544
545 if (rootfs == NULL || strlen(rootfs) == 0)
546 return -2;
547
548 absrootfs = realpath(rootfs, NULL);
549 if (!absrootfs)
550 return -2;
551
552 ret = stat(absrootfs, &s);
553 if (ret < 0)
554 return -1;
555
556 if (!S_ISDIR(s.st_mode))
557 return -2;
558
559 ret = snprintf(absrootfspin, PATH_MAX, "%s/.lxc-keep", absrootfs);
560 if (ret < 0 || ret >= PATH_MAX)
561 return -1;
562
563 fd = open(absrootfspin, O_CREAT | O_RDWR, S_IWUSR | S_IRUSR);
564 if (fd < 0)
565 return fd;
566
567 ret = fstatfs (fd, &sfs);
568 if (ret < 0)
569 return fd;
570
571 if (sfs.f_type == NFS_SUPER_MAGIC) {
572 DEBUG("Rootfs on NFS, not unlinking pin file \"%s\"", absrootfspin);
573 return fd;
574 }
575
576 (void)unlink(absrootfspin);
577
578 return fd;
579 }
580
581 /* If we are asking to remount something, make sure that any NOEXEC etc are
582 * honored.
583 */
584 unsigned long add_required_remount_flags(const char *s, const char *d,
585 unsigned long flags)
586 {
587 #ifdef HAVE_STATVFS
588 int ret;
589 struct statvfs sb;
590 unsigned long required_flags = 0;
591
592 if (!s)
593 s = d;
594
595 if (!s)
596 return flags;
597
598 ret = statvfs(s, &sb);
599 if (ret < 0)
600 return flags;
601
602 if (flags & MS_REMOUNT) {
603 if (sb.f_flag & MS_NOSUID)
604 required_flags |= MS_NOSUID;
605 if (sb.f_flag & MS_NODEV)
606 required_flags |= MS_NODEV;
607 if (sb.f_flag & MS_RDONLY)
608 required_flags |= MS_RDONLY;
609 if (sb.f_flag & MS_NOEXEC)
610 required_flags |= MS_NOEXEC;
611 }
612
613 if (sb.f_flag & MS_NOATIME)
614 required_flags |= MS_NOATIME;
615 if (sb.f_flag & MS_NODIRATIME)
616 required_flags |= MS_NODIRATIME;
617 if (sb.f_flag & MS_LAZYTIME)
618 required_flags |= MS_LAZYTIME;
619 if (sb.f_flag & MS_RELATIME)
620 required_flags |= MS_RELATIME;
621 if (sb.f_flag & MS_STRICTATIME)
622 required_flags |= MS_STRICTATIME;
623
624 return flags | required_flags;
625 #else
626 return flags;
627 #endif
628 }
629
630 static int add_shmount_to_list(struct lxc_conf *conf)
631 {
632 char new_mount[PATH_MAX];
633 /* Offset for the leading '/' since the path_cont
634 * is absolute inside the container.
635 */
636 int offset = 1, ret = -1;
637
638 ret = snprintf(new_mount, sizeof(new_mount),
639 "%s %s none bind,create=dir 0 0", conf->shmount.path_host,
640 conf->shmount.path_cont + offset);
641 if (ret < 0 || (size_t)ret >= sizeof(new_mount))
642 return -1;
643
644 return add_elem_to_mount_list(new_mount, conf);
645 }
646
647 static int lxc_mount_auto_mounts(struct lxc_conf *conf, int flags, struct lxc_handler *handler)
648 {
649 int i, r;
650 static struct {
651 int match_mask;
652 int match_flag;
653 const char *source;
654 const char *destination;
655 const char *fstype;
656 unsigned long flags;
657 const char *options;
658 } default_mounts[] = {
659 /* Read-only bind-mounting... In older kernels, doing that
660 * required to do one MS_BIND mount and then
661 * MS_REMOUNT|MS_RDONLY the same one. According to mount(2)
662 * manpage, MS_BIND honors MS_RDONLY from kernel 2.6.26
663 * onwards. However, this apparently does not work on kernel
664 * 3.8. Unfortunately, on that very same kernel, doing the same
665 * trick as above doesn't seem to work either, there one needs
666 * to ALSO specify MS_BIND for the remount, otherwise the
667 * entire fs is remounted read-only or the mount fails because
668 * it's busy... MS_REMOUNT|MS_BIND|MS_RDONLY seems to work for
669 * kernels as low as 2.6.32...
670 */
671 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, "proc", "%r/proc", "proc", MS_NODEV|MS_NOEXEC|MS_NOSUID, NULL },
672 /* proc/tty is used as a temporary placeholder for proc/sys/net which we'll move back in a few steps */
673 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, "%r/proc/sys/net", "%r/proc/tty", NULL, MS_BIND, NULL },
674 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, "%r/proc/sys", "%r/proc/sys", NULL, MS_BIND, NULL },
675 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, NULL, "%r/proc/sys", NULL, MS_REMOUNT|MS_BIND|MS_RDONLY, NULL },
676 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, "%r/proc/tty", "%r/proc/sys/net", NULL, MS_MOVE, NULL },
677 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, "%r/proc/sysrq-trigger", "%r/proc/sysrq-trigger", NULL, MS_BIND, NULL },
678 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_MIXED, NULL, "%r/proc/sysrq-trigger", NULL, MS_REMOUNT|MS_BIND|MS_RDONLY, NULL },
679 { LXC_AUTO_PROC_MASK, LXC_AUTO_PROC_RW, "proc", "%r/proc", "proc", MS_NODEV|MS_NOEXEC|MS_NOSUID, NULL },
680 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_RW, "sysfs", "%r/sys", "sysfs", 0, NULL },
681 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_RO, "sysfs", "%r/sys", "sysfs", MS_RDONLY, NULL },
682 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_MIXED, "sysfs", "%r/sys", "sysfs", MS_NODEV|MS_NOEXEC|MS_NOSUID, NULL },
683 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_MIXED, "%r/sys", "%r/sys", NULL, MS_BIND, NULL },
684 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_MIXED, NULL, "%r/sys", NULL, MS_REMOUNT|MS_BIND|MS_RDONLY, NULL },
685 { LXC_AUTO_SYS_MASK, LXC_AUTO_SYS_MIXED, "sysfs", "%r/sys/devices/virtual/net", "sysfs", 0, NULL },
686 { 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 },
687 { 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 },
688 { 0, 0, NULL, NULL, NULL, 0, NULL }
689 };
690
691 for (i = 0; default_mounts[i].match_mask; i++) {
692 __do_free char *destination = NULL, *source = NULL;
693 int saved_errno;
694 unsigned long mflags;
695 if ((flags & default_mounts[i].match_mask) != default_mounts[i].match_flag)
696 continue;
697
698 if (default_mounts[i].source) {
699 /* will act like strdup if %r is not present */
700 source = lxc_string_replace("%r", conf->rootfs.path ? conf->rootfs.mount : "", default_mounts[i].source);
701 if (!source)
702 return -1;
703 }
704
705 if (!default_mounts[i].destination) {
706 ERROR("BUG: auto mounts destination %d was NULL", i);
707 return -1;
708 }
709
710 /* will act like strdup if %r is not present */
711 destination = lxc_string_replace("%r", conf->rootfs.path ? conf->rootfs.mount : "", default_mounts[i].destination);
712 if (!destination) {
713 return -1;
714 }
715
716 mflags = add_required_remount_flags(source, destination,
717 default_mounts[i].flags);
718 r = safe_mount(source, destination, default_mounts[i].fstype,
719 mflags, default_mounts[i].options,
720 conf->rootfs.path ? conf->rootfs.mount : NULL);
721 saved_errno = errno;
722 if (r < 0 && errno == ENOENT) {
723 INFO("Mount source or target for \"%s\" on \"%s\" does "
724 "not exist. Skipping", source, destination);
725 r = 0;
726 } else if (r < 0) {
727 SYSERROR("Failed to mount \"%s\" on \"%s\" with flags %lu", source, destination, mflags);
728 }
729
730 if (r < 0) {
731 errno = saved_errno;
732 return -1;
733 }
734 }
735
736 if (flags & LXC_AUTO_CGROUP_MASK) {
737 int cg_flags;
738
739 cg_flags = flags & (LXC_AUTO_CGROUP_MASK & ~LXC_AUTO_CGROUP_FORCE);
740 /* If the type of cgroup mount was not specified, it depends on
741 * the container's capabilities as to what makes sense: if we
742 * have CAP_SYS_ADMIN, the read-only part can be remounted
743 * read-write anyway, so we may as well default to read-write;
744 * then the admin will not be given a false sense of security.
745 * (And if they really want mixed r/o r/w, then they can
746 * explicitly specify :mixed.) OTOH, if the container lacks
747 * CAP_SYS_ADMIN, do only default to :mixed, because then the
748 * container can't remount it read-write.
749 */
750 if (cg_flags == LXC_AUTO_CGROUP_NOSPEC || cg_flags == LXC_AUTO_CGROUP_FULL_NOSPEC) {
751 int has_sys_admin = 0;
752
753 if (!lxc_list_empty(&conf->keepcaps))
754 has_sys_admin = in_caplist(CAP_SYS_ADMIN, &conf->keepcaps);
755 else
756 has_sys_admin = !in_caplist(CAP_SYS_ADMIN, &conf->caps);
757
758 if (cg_flags == LXC_AUTO_CGROUP_NOSPEC)
759 cg_flags = has_sys_admin ? LXC_AUTO_CGROUP_RW : LXC_AUTO_CGROUP_MIXED;
760 else
761 cg_flags = has_sys_admin ? LXC_AUTO_CGROUP_FULL_RW : LXC_AUTO_CGROUP_FULL_MIXED;
762 }
763
764 if (flags & LXC_AUTO_CGROUP_FORCE)
765 cg_flags |= LXC_AUTO_CGROUP_FORCE;
766
767 if (!handler->cgroup_ops->mount(handler->cgroup_ops,
768 handler,
769 conf->rootfs.path ? conf->rootfs.mount : "",
770 cg_flags)) {
771 SYSERROR("Failed to mount \"/sys/fs/cgroup\"");
772 return -1;
773 }
774 }
775
776 if (flags & LXC_AUTO_SHMOUNTS_MASK) {
777 int ret = add_shmount_to_list(conf);
778 if (ret < 0) {
779 ERROR("Failed to add shmount entry to container config");
780 return -1;
781 }
782 }
783
784 return 0;
785 }
786
787 static int setup_utsname(struct utsname *utsname)
788 {
789 int ret;
790
791 if (!utsname)
792 return 0;
793
794 ret = sethostname(utsname->nodename, strlen(utsname->nodename));
795 if (ret < 0) {
796 SYSERROR("Failed to set the hostname to \"%s\"", utsname->nodename);
797 return -1;
798 }
799
800 INFO("Set hostname to \"%s\"", utsname->nodename);
801
802 return 0;
803 }
804
805 struct dev_symlinks {
806 const char *oldpath;
807 const char *name;
808 };
809
810 static const struct dev_symlinks dev_symlinks[] = {
811 { "/proc/self/fd", "fd" },
812 { "/proc/self/fd/0", "stdin" },
813 { "/proc/self/fd/1", "stdout" },
814 { "/proc/self/fd/2", "stderr" },
815 };
816
817 static int lxc_setup_dev_symlinks(const struct lxc_rootfs *rootfs)
818 {
819 int i, ret;
820 char path[PATH_MAX];
821 struct stat s;
822
823 for (i = 0; i < sizeof(dev_symlinks) / sizeof(dev_symlinks[0]); i++) {
824 const struct dev_symlinks *d = &dev_symlinks[i];
825
826 ret = snprintf(path, sizeof(path), "%s/dev/%s",
827 rootfs->path ? rootfs->mount : "", d->name);
828 if (ret < 0 || ret >= PATH_MAX)
829 return -1;
830
831 /* Stat the path first. If we don't get an error accept it as
832 * is and don't try to create it
833 */
834 ret = stat(path, &s);
835 if (ret == 0)
836 continue;
837
838 ret = symlink(d->oldpath, path);
839 if (ret && errno != EEXIST) {
840 if (errno == EROFS) {
841 WARN("Failed to create \"%s\". Read-only filesystem", path);
842 } else {
843 SYSERROR("Failed to create \"%s\"", path);
844 return -1;
845 }
846 }
847 }
848
849 return 0;
850 }
851
852 /* Build a space-separate list of ptys to pass to systemd. */
853 static bool append_ttyname(char **pp, char *name)
854 {
855 char *p;
856 size_t size;
857
858 if (!*pp) {
859 *pp = malloc(strlen(name) + strlen("container_ttys=") + 1);
860 if (!*pp)
861 return false;
862
863 sprintf(*pp, "container_ttys=%s", name);
864 return true;
865 }
866
867 size = strlen(*pp) + strlen(name) + 2;
868 p = realloc(*pp, size);
869 if (!p)
870 return false;
871
872 *pp = p;
873 (void)strlcat(p, " ", size);
874 (void)strlcat(p, name, size);
875
876 return true;
877 }
878
879 static int lxc_setup_ttys(struct lxc_conf *conf)
880 {
881 int i, ret;
882 const struct lxc_tty_info *ttys = &conf->ttys;
883 char *ttydir = ttys->dir;
884 char path[PATH_MAX], lxcpath[PATH_MAX];
885
886 if (!conf->rootfs.path)
887 return 0;
888
889 for (i = 0; i < ttys->max; i++) {
890 struct lxc_terminal_info *tty = &ttys->tty[i];
891
892 ret = snprintf(path, sizeof(path), "/dev/tty%d", i + 1);
893 if (ret < 0 || (size_t)ret >= sizeof(path))
894 return -1;
895
896 if (ttydir) {
897 /* create dev/lxc/tty%d" */
898 ret = snprintf(lxcpath, sizeof(lxcpath),
899 "/dev/%s/tty%d", ttydir, i + 1);
900 if (ret < 0 || (size_t)ret >= sizeof(lxcpath))
901 return -1;
902
903 ret = mknod(lxcpath, S_IFREG | 0000, 0);
904 if (ret < 0 && errno != EEXIST) {
905 SYSERROR("Failed to create \"%s\"", lxcpath);
906 return -1;
907 }
908
909 ret = unlink(path);
910 if (ret < 0 && errno != ENOENT) {
911 SYSERROR("Failed to unlink \"%s\"", path);
912 return -1;
913 }
914
915 ret = mount(tty->name, lxcpath, "none", MS_BIND, 0);
916 if (ret < 0) {
917 SYSWARN("Failed to bind mount \"%s\" onto \"%s\"",
918 tty->name, lxcpath);
919 continue;
920 }
921 DEBUG("Bind mounted \"%s\" onto \"%s\"", tty->name,
922 lxcpath);
923
924 ret = snprintf(lxcpath, sizeof(lxcpath), "%s/tty%d",
925 ttydir, i + 1);
926 if (ret < 0 || (size_t)ret >= sizeof(lxcpath))
927 return -1;
928
929 ret = symlink(lxcpath, path);
930 if (ret < 0) {
931 SYSERROR("Failed to create symlink \"%s\" -> \"%s\"",
932 path, lxcpath);
933 return -1;
934 }
935 } else {
936 /* If we populated /dev, then we need to create
937 * /dev/ttyN
938 */
939 ret = mknod(path, S_IFREG | 0000, 0);
940 if (ret < 0) /* this isn't fatal, continue */
941 SYSERROR("Failed to create \"%s\"", path);
942
943 ret = mount(tty->name, path, "none", MS_BIND, 0);
944 if (ret < 0) {
945 SYSERROR("Failed to mount '%s'->'%s'", tty->name, path);
946 continue;
947 }
948
949 DEBUG("Bind mounted \"%s\" onto \"%s\"", tty->name, path);
950 }
951
952 if (!append_ttyname(&conf->ttys.tty_names, tty->name)) {
953 ERROR("Error setting up container_ttys string");
954 return -1;
955 }
956 }
957
958 INFO("Finished setting up %zu /dev/tty<N> device(s)", ttys->max);
959 return 0;
960 }
961
962 int lxc_allocate_ttys(struct lxc_conf *conf)
963 {
964 size_t i;
965 int ret;
966 struct lxc_tty_info *ttys = &conf->ttys;
967
968 /* no tty in the configuration */
969 if (ttys->max == 0)
970 return 0;
971
972 ttys->tty = malloc(sizeof(*ttys->tty) * ttys->max);
973 if (!ttys->tty)
974 return -ENOMEM;
975
976 for (i = 0; i < ttys->max; i++) {
977 struct lxc_terminal_info *tty = &ttys->tty[i];
978
979 tty->master = -EBADF;
980 tty->slave = -EBADF;
981 ret = openpty(&tty->master, &tty->slave, NULL, NULL, NULL);
982 if (ret < 0) {
983 SYSERROR("Failed to create tty %zu", i);
984 ttys->max = i;
985 lxc_delete_tty(ttys);
986 return -ENOTTY;
987 }
988
989 ret = ttyname_r(tty->slave, tty->name, sizeof(tty->name));
990 if (ret < 0) {
991 SYSERROR("Failed to retrieve name of tty %zu slave", i);
992 ttys->max = i;
993 lxc_delete_tty(ttys);
994 return -ENOTTY;
995 }
996
997 DEBUG("Created tty \"%s\" with master fd %d and slave fd %d",
998 tty->name, tty->master, tty->slave);
999
1000 /* Prevent leaking the file descriptors to the container */
1001 ret = fd_cloexec(tty->master, true);
1002 if (ret < 0)
1003 SYSWARN("Failed to set FD_CLOEXEC flag on master fd %d of "
1004 "tty device \"%s\"", tty->master, tty->name);
1005
1006 ret = fd_cloexec(tty->slave, true);
1007 if (ret < 0)
1008 SYSWARN("Failed to set FD_CLOEXEC flag on slave fd %d of "
1009 "tty device \"%s\"", tty->slave, tty->name);
1010
1011 tty->busy = 0;
1012 }
1013
1014 INFO("Finished creating %zu tty devices", ttys->max);
1015 return 0;
1016 }
1017
1018 void lxc_delete_tty(struct lxc_tty_info *ttys)
1019 {
1020 int i;
1021
1022 if (!ttys->tty)
1023 return;
1024
1025 for (i = 0; i < ttys->max; i++) {
1026 struct lxc_terminal_info *tty = &ttys->tty[i];
1027
1028 if (tty->master >= 0) {
1029 close(tty->master);
1030 tty->master = -EBADF;
1031 }
1032
1033 if (tty->slave >= 0) {
1034 close(tty->slave);
1035 tty->slave = -EBADF;
1036 }
1037 }
1038
1039 free(ttys->tty);
1040 ttys->tty = NULL;
1041 }
1042
1043 static int lxc_send_ttys_to_parent(struct lxc_handler *handler)
1044 {
1045 int i;
1046 int ret = -1;
1047 struct lxc_conf *conf = handler->conf;
1048 struct lxc_tty_info *ttys = &conf->ttys;
1049 int sock = handler->data_sock[0];
1050
1051 if (ttys->max == 0)
1052 return 0;
1053
1054 for (i = 0; i < ttys->max; i++) {
1055 int ttyfds[2];
1056 struct lxc_terminal_info *tty = &ttys->tty[i];
1057
1058 ttyfds[0] = tty->master;
1059 ttyfds[1] = tty->slave;
1060
1061 ret = lxc_abstract_unix_send_fds(sock, ttyfds, 2, NULL, 0);
1062 if (ret < 0)
1063 break;
1064
1065 TRACE("Sent tty \"%s\" with master fd %d and slave fd %d to "
1066 "parent", tty->name, tty->master, tty->slave);
1067 }
1068
1069 if (ret < 0)
1070 SYSERROR("Failed to send %zu ttys to parent", ttys->max);
1071 else
1072 TRACE("Sent %zu ttys to parent", ttys->max);
1073
1074 return ret;
1075 }
1076
1077 static int lxc_create_ttys(struct lxc_handler *handler)
1078 {
1079 int ret = -1;
1080 struct lxc_conf *conf = handler->conf;
1081
1082 ret = lxc_allocate_ttys(conf);
1083 if (ret < 0) {
1084 ERROR("Failed to allocate ttys");
1085 goto on_error;
1086 }
1087
1088 ret = lxc_send_ttys_to_parent(handler);
1089 if (ret < 0) {
1090 ERROR("Failed to send ttys to parent");
1091 goto on_error;
1092 }
1093
1094 if (!conf->is_execute) {
1095 ret = lxc_setup_ttys(conf);
1096 if (ret < 0) {
1097 ERROR("Failed to setup ttys");
1098 goto on_error;
1099 }
1100 }
1101
1102 if (conf->ttys.tty_names) {
1103 ret = setenv("container_ttys", conf->ttys.tty_names, 1);
1104 if (ret < 0)
1105 SYSERROR("Failed to set \"container_ttys=%s\"", conf->ttys.tty_names);
1106 }
1107
1108 ret = 0;
1109
1110 on_error:
1111 lxc_delete_tty(&conf->ttys);
1112
1113 return ret;
1114 }
1115
1116 /* Just create a path for /dev under $lxcpath/$name and in rootfs If we hit an
1117 * error, log it but don't fail yet.
1118 */
1119 static int mount_autodev(const char *name, const struct lxc_rootfs *rootfs,
1120 const char *lxcpath)
1121 {
1122 __do_free char *path = NULL;
1123 int ret;
1124 size_t clen;
1125 mode_t cur_mask;
1126
1127 INFO("Preparing \"/dev\"");
1128
1129 /* $(rootfs->mount) + "/dev/pts" + '\0' */
1130 clen = (rootfs->path ? strlen(rootfs->mount) : 0) + 9;
1131 path = must_realloc(NULL, clen);
1132
1133 ret = snprintf(path, clen, "%s/dev", rootfs->path ? rootfs->mount : "");
1134 if (ret < 0 || (size_t)ret >= clen)
1135 return -1;
1136
1137 cur_mask = umask(S_IXUSR | S_IXGRP | S_IXOTH);
1138 ret = mkdir(path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
1139 if (ret < 0 && errno != EEXIST) {
1140 SYSERROR("Failed to create \"/dev\" directory");
1141 ret = -errno;
1142 goto reset_umask;
1143 }
1144
1145 ret = safe_mount("none", path, "tmpfs", 0, "size=500000,mode=755",
1146 rootfs->path ? rootfs->mount : NULL);
1147 if (ret < 0) {
1148 SYSERROR("Failed to mount tmpfs on \"%s\"", path);
1149 goto reset_umask;
1150 }
1151 TRACE("Mounted tmpfs on \"%s\"", path);
1152
1153 ret = snprintf(path, clen, "%s/dev/pts", rootfs->path ? rootfs->mount : "");
1154 if (ret < 0 || (size_t)ret >= clen) {
1155 ret = -1;
1156 goto reset_umask;
1157 }
1158
1159 /* If we are running on a devtmpfs mapping, dev/pts may already exist.
1160 * If not, then create it and exit if that fails...
1161 */
1162 ret = mkdir(path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
1163 if (ret < 0 && errno != EEXIST) {
1164 SYSERROR("Failed to create directory \"%s\"", path);
1165 ret = -errno;
1166 goto reset_umask;
1167 }
1168
1169 ret = 0;
1170
1171 reset_umask:
1172 (void)umask(cur_mask);
1173
1174 INFO("Prepared \"/dev\"");
1175 return ret;
1176 }
1177
1178 struct lxc_device_node {
1179 const char *name;
1180 const mode_t mode;
1181 const int maj;
1182 const int min;
1183 };
1184
1185 static const struct lxc_device_node lxc_devices[] = {
1186 { "full", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 7 },
1187 { "null", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 3 },
1188 { "random", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 8 },
1189 { "tty", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 5, 0 },
1190 { "urandom", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 9 },
1191 { "zero", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 5 },
1192 };
1193
1194
1195 enum {
1196 LXC_DEVNODE_BIND,
1197 LXC_DEVNODE_MKNOD,
1198 LXC_DEVNODE_PARTIAL,
1199 LXC_DEVNODE_OPEN,
1200 };
1201
1202 static int lxc_fill_autodev(const struct lxc_rootfs *rootfs)
1203 {
1204 int i, ret;
1205 char path[PATH_MAX];
1206 mode_t cmask;
1207 int use_mknod = LXC_DEVNODE_MKNOD;
1208
1209 ret = snprintf(path, PATH_MAX, "%s/dev",
1210 rootfs->path ? rootfs->mount : "");
1211 if (ret < 0 || ret >= PATH_MAX)
1212 return -1;
1213
1214 /* ignore, just don't try to fill in */
1215 if (!dir_exists(path))
1216 return 0;
1217
1218 INFO("Populating \"/dev\"");
1219
1220 cmask = umask(S_IXUSR | S_IXGRP | S_IXOTH);
1221 for (i = 0; i < sizeof(lxc_devices) / sizeof(lxc_devices[0]); i++) {
1222 char hostpath[PATH_MAX];
1223 const struct lxc_device_node *device = &lxc_devices[i];
1224
1225 ret = snprintf(path, PATH_MAX, "%s/dev/%s",
1226 rootfs->path ? rootfs->mount : "", device->name);
1227 if (ret < 0 || ret >= PATH_MAX)
1228 return -1;
1229
1230 if (use_mknod >= LXC_DEVNODE_MKNOD) {
1231 ret = mknod(path, device->mode, makedev(device->maj, device->min));
1232 if (ret == 0 || (ret < 0 && errno == EEXIST)) {
1233 DEBUG("Created device node \"%s\"", path);
1234 } else if (ret < 0) {
1235 if (errno != EPERM) {
1236 SYSERROR("Failed to create device node \"%s\"", path);
1237 return -1;
1238 }
1239
1240 use_mknod = LXC_DEVNODE_BIND;
1241 }
1242
1243 /* Device nodes are fully useable. */
1244 if (use_mknod == LXC_DEVNODE_OPEN)
1245 continue;
1246
1247 if (use_mknod == LXC_DEVNODE_MKNOD) {
1248 /* See
1249 * - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=55956b59df336f6738da916dbb520b6e37df9fbd
1250 * - https://lists.linuxfoundation.org/pipermail/containers/2018-June/039176.html
1251 */
1252 ret = open(path, O_RDONLY | O_CLOEXEC);
1253 if (ret >= 0) {
1254 close_prot_errno_disarm(ret);
1255 /* Device nodes are fully useable. */
1256 use_mknod = LXC_DEVNODE_OPEN;
1257 continue;
1258 }
1259
1260 SYSTRACE("Failed to open \"%s\" device", path);
1261 /* Device nodes are only partially useable. */
1262 use_mknod = LXC_DEVNODE_PARTIAL;
1263 }
1264 }
1265
1266 if (use_mknod != LXC_DEVNODE_PARTIAL) {
1267 /* If we are dealing with partially functional device
1268 * nodes the prio mknod() call will have created the
1269 * device node so we can use it as a bind-mount target.
1270 */
1271 ret = mknod(path, S_IFREG | 0000, 0);
1272 if (ret < 0 && errno != EEXIST) {
1273 SYSERROR("Failed to create file \"%s\"", path);
1274 return -1;
1275 }
1276 }
1277
1278 /* Fallback to bind-mounting the device from the host. */
1279 ret = snprintf(hostpath, PATH_MAX, "/dev/%s", device->name);
1280 if (ret < 0 || ret >= PATH_MAX)
1281 return -1;
1282
1283 ret = safe_mount(hostpath, path, 0, MS_BIND, NULL,
1284 rootfs->path ? rootfs->mount : NULL);
1285 if (ret < 0) {
1286 SYSERROR("Failed to bind mount host device node \"%s\" "
1287 "onto \"%s\"", hostpath, path);
1288 return -1;
1289 }
1290 DEBUG("Bind mounted host device node \"%s\" onto \"%s\"",
1291 hostpath, path);
1292 }
1293 (void)umask(cmask);
1294
1295 INFO("Populated \"/dev\"");
1296 return 0;
1297 }
1298
1299 static int lxc_mount_rootfs(struct lxc_conf *conf)
1300 {
1301 int ret;
1302 struct lxc_storage *bdev;
1303 const struct lxc_rootfs *rootfs = &conf->rootfs;
1304
1305 if (!rootfs->path) {
1306 ret = mount("", "/", NULL, MS_SLAVE | MS_REC, 0);
1307 if (ret < 0) {
1308 SYSERROR("Failed to remount \"/\" MS_REC | MS_SLAVE");
1309 return -1;
1310 }
1311
1312 return 0;
1313 }
1314
1315 ret = access(rootfs->mount, F_OK);
1316 if (ret != 0) {
1317 SYSERROR("Failed to access to \"%s\". Check it is present",
1318 rootfs->mount);
1319 return -1;
1320 }
1321
1322 bdev = storage_init(conf);
1323 if (!bdev) {
1324 ERROR("Failed to mount rootfs \"%s\" onto \"%s\" with options \"%s\"",
1325 rootfs->path, rootfs->mount,
1326 rootfs->options ? rootfs->options : "(null)");
1327 return -1;
1328 }
1329
1330 ret = bdev->ops->mount(bdev);
1331 storage_put(bdev);
1332 if (ret < 0) {
1333 ERROR("Failed to mount rootfs \"%s\" onto \"%s\" with options \"%s\"",
1334 rootfs->path, rootfs->mount,
1335 rootfs->options ? rootfs->options : "(null)");
1336 return -1;
1337 }
1338
1339 DEBUG("Mounted rootfs \"%s\" onto \"%s\" with options \"%s\"",
1340 rootfs->path, rootfs->mount,
1341 rootfs->options ? rootfs->options : "(null)");
1342
1343 return 0;
1344 }
1345
1346 int lxc_chroot(const struct lxc_rootfs *rootfs)
1347 {
1348 __do_free char *nroot = NULL;
1349 int i, ret;
1350 char *p, *p2;
1351 char buf[LXC_LINELEN];
1352 char *root = rootfs->mount;
1353
1354 nroot = realpath(root, NULL);
1355 if (!nroot) {
1356 SYSERROR("Failed to resolve \"%s\"", root);
1357 return -1;
1358 }
1359
1360 ret = chdir("/");
1361 if (ret < 0)
1362 return -1;
1363
1364 /* We could use here MS_MOVE, but in userns this mount is locked and
1365 * can't be moved.
1366 */
1367 ret = mount(nroot, "/", NULL, MS_REC | MS_BIND, NULL);
1368 if (ret < 0) {
1369 SYSERROR("Failed to mount \"%s\" onto \"/\" as MS_REC | MS_BIND", nroot);
1370 return -1;
1371 }
1372
1373 ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL);
1374 if (ret < 0) {
1375 SYSERROR("Failed to remount \"/\"");
1376 return -1;
1377 }
1378
1379 /* The following code cleans up inherited mounts which are not required
1380 * for CT.
1381 *
1382 * The mountinfo file shows not all mounts, if a few points have been
1383 * unmounted between read operations from the mountinfo. So we need to
1384 * read mountinfo a few times.
1385 *
1386 * This loop can be skipped if a container uses userns, because all
1387 * inherited mounts are locked and we should live with all this trash.
1388 */
1389 for (;;) {
1390 __do_fclose FILE *f = NULL;
1391 int progress = 0;
1392
1393 f = fopen("./proc/self/mountinfo", "r");
1394 if (!f) {
1395 SYSERROR("Failed to open \"/proc/self/mountinfo\"");
1396 return -1;
1397 }
1398
1399 while (fgets(buf, LXC_LINELEN, f)) {
1400 for (p = buf, i=0; p && i < 4; i++)
1401 p = strchr(p+1, ' ');
1402
1403 if (!p)
1404 continue;
1405
1406 p2 = strchr(p+1, ' ');
1407 if (!p2)
1408 continue;
1409
1410 *p2 = '\0';
1411 *p = '.';
1412
1413 if (strcmp(p + 1, "/") == 0)
1414 continue;
1415
1416 if (strcmp(p + 1, "/proc") == 0)
1417 continue;
1418
1419 ret = umount2(p, MNT_DETACH);
1420 if (ret == 0)
1421 progress++;
1422 }
1423
1424 if (!progress)
1425 break;
1426 }
1427
1428 /* This also can be skipped if a container uses userns. */
1429 (void)umount2("./proc", MNT_DETACH);
1430
1431 /* It is weird, but chdir("..") moves us in a new root */
1432 ret = chdir("..");
1433 if (ret < 0) {
1434 SYSERROR("Failed to chdir(\"..\")");
1435 return -1;
1436 }
1437
1438 ret = chroot(".");
1439 if (ret < 0) {
1440 SYSERROR("Failed to chroot(\".\")");
1441 return -1;
1442 }
1443
1444 return 0;
1445 }
1446
1447 /* (The following explanation is copied verbatim from the kernel.)
1448 *
1449 * pivot_root Semantics:
1450 * Moves the root file system of the current process to the directory put_old,
1451 * makes new_root as the new root file system of the current process, and sets
1452 * root/cwd of all processes which had them on the current root to new_root.
1453 *
1454 * Restrictions:
1455 * The new_root and put_old must be directories, and must not be on the
1456 * same file system as the current process root. The put_old must be
1457 * underneath new_root, i.e. adding a non-zero number of /.. to the string
1458 * pointed to by put_old must yield the same directory as new_root. No other
1459 * file system may be mounted on put_old. After all, new_root is a mountpoint.
1460 *
1461 * Also, the current root cannot be on the 'rootfs' (initial ramfs) filesystem.
1462 * See Documentation/filesystems/ramfs-rootfs-initramfs.txt for alternatives
1463 * in this situation.
1464 *
1465 * Notes:
1466 * - we don't move root/cwd if they are not at the root (reason: if something
1467 * cared enough to change them, it's probably wrong to force them elsewhere)
1468 * - it's okay to pick a root that isn't the root of a file system, e.g.
1469 * /nfs/my_root where /nfs is the mount point. It must be a mountpoint,
1470 * though, so you may need to say mount --bind /nfs/my_root /nfs/my_root
1471 * first.
1472 */
1473 static int lxc_pivot_root(const char *rootfs)
1474 {
1475 __do_close_prot_errno int oldroot = -EBADF, newroot = -EBADF;
1476 int ret;
1477
1478 oldroot = open("/", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
1479 if (oldroot < 0) {
1480 SYSERROR("Failed to open old root directory");
1481 return -1;
1482 }
1483
1484 newroot = open(rootfs, O_DIRECTORY | O_RDONLY | O_CLOEXEC);
1485 if (newroot < 0) {
1486 SYSERROR("Failed to open new root directory");
1487 return -1;
1488 }
1489
1490 /* change into new root fs */
1491 ret = fchdir(newroot);
1492 if (ret < 0) {
1493 SYSERROR("Failed to change to new rootfs \"%s\"", rootfs);
1494 return -1;
1495 }
1496
1497 /* pivot_root into our new root fs */
1498 ret = pivot_root(".", ".");
1499 if (ret < 0) {
1500 SYSERROR("Failed to pivot_root()");
1501 return -1;
1502 }
1503
1504 /* At this point the old-root is mounted on top of our new-root. To
1505 * unmounted it we must not be chdir'd into it, so escape back to
1506 * old-root.
1507 */
1508 ret = fchdir(oldroot);
1509 if (ret < 0) {
1510 SYSERROR("Failed to enter old root directory");
1511 return -1;
1512 }
1513
1514 /* Make oldroot rslave to make sure our umounts don't propagate to the
1515 * host.
1516 */
1517 ret = mount("", ".", "", MS_SLAVE | MS_REC, NULL);
1518 if (ret < 0) {
1519 SYSERROR("Failed to make oldroot rslave");
1520 return -1;
1521 }
1522
1523 ret = umount2(".", MNT_DETACH);
1524 if (ret < 0) {
1525 SYSERROR("Failed to detach old root directory");
1526 return -1;
1527 }
1528
1529 ret = fchdir(newroot);
1530 if (ret < 0) {
1531 SYSERROR("Failed to re-enter new root directory");
1532 return -1;
1533 }
1534
1535 TRACE("pivot_root(\"%s\") successful", rootfs);
1536
1537 return 0;
1538 }
1539
1540 static int lxc_setup_rootfs_switch_root(const struct lxc_rootfs *rootfs)
1541 {
1542 if (!rootfs->path) {
1543 DEBUG("Container does not have a rootfs");
1544 return 0;
1545 }
1546
1547 if (detect_ramfs_rootfs())
1548 return lxc_chroot(rootfs);
1549
1550 return lxc_pivot_root(rootfs->mount);
1551 }
1552
1553 static const struct id_map *find_mapped_nsid_entry(struct lxc_conf *conf,
1554 unsigned id,
1555 enum idtype idtype)
1556 {
1557 struct lxc_list *it;
1558 struct id_map *map;
1559 struct id_map *retmap = NULL;
1560
1561 /* Shortcut for container's root mappings. */
1562 if (id == 0) {
1563 if (idtype == ID_TYPE_UID)
1564 return conf->root_nsuid_map;
1565
1566 if (idtype == ID_TYPE_GID)
1567 return conf->root_nsgid_map;
1568 }
1569
1570 lxc_list_for_each(it, &conf->id_map) {
1571 map = it->elem;
1572 if (map->idtype != idtype)
1573 continue;
1574
1575 if (id >= map->nsid && id < map->nsid + map->range) {
1576 retmap = map;
1577 break;
1578 }
1579 }
1580
1581 return retmap;
1582 }
1583
1584 static int lxc_setup_devpts(struct lxc_conf *conf)
1585 {
1586 int ret;
1587 char **opts;
1588 char devpts_mntopts[256];
1589 char *mntopt_sets[5];
1590 char default_devpts_mntopts[256] = "gid=5,newinstance,ptmxmode=0666,mode=0620";
1591
1592 if (conf->pty_max <= 0) {
1593 DEBUG("No new devpts instance will be mounted since no pts "
1594 "devices are requested");
1595 return 0;
1596 }
1597
1598 ret = snprintf(devpts_mntopts, sizeof(devpts_mntopts), "%s,max=%zu",
1599 default_devpts_mntopts, conf->pty_max);
1600 if (ret < 0 || (size_t)ret >= sizeof(devpts_mntopts))
1601 return -1;
1602
1603 (void)umount2("/dev/pts", MNT_DETACH);
1604
1605 /* Create mountpoint for devpts instance. */
1606 ret = mkdir("/dev/pts", 0755);
1607 if (ret < 0 && errno != EEXIST) {
1608 SYSERROR("Failed to create \"/dev/pts\" directory");
1609 return -1;
1610 }
1611
1612 /* gid=5 && max= */
1613 mntopt_sets[0] = devpts_mntopts;
1614
1615 /* !gid=5 && max= */
1616 mntopt_sets[1] = devpts_mntopts + STRLITERALLEN("gid=5") + 1;
1617
1618 /* gid=5 && !max= */
1619 mntopt_sets[2] = default_devpts_mntopts;
1620
1621 /* !gid=5 && !max= */
1622 mntopt_sets[3] = default_devpts_mntopts + STRLITERALLEN("gid=5") + 1;
1623
1624 /* end */
1625 mntopt_sets[4] = NULL;
1626
1627 for (ret = -1, opts = mntopt_sets; opts && *opts; opts++) {
1628 /* mount new devpts instance */
1629 ret = mount("devpts", "/dev/pts", "devpts", MS_NOSUID | MS_NOEXEC, *opts);
1630 if (ret == 0)
1631 break;
1632 }
1633
1634 if (ret < 0) {
1635 SYSERROR("Failed to mount new devpts instance");
1636 return -1;
1637 }
1638 DEBUG("Mount new devpts instance with options \"%s\"", *opts);
1639
1640 /* Remove any pre-existing /dev/ptmx file. */
1641 ret = remove("/dev/ptmx");
1642 if (ret < 0) {
1643 if (errno != ENOENT) {
1644 SYSERROR("Failed to remove existing \"/dev/ptmx\" file");
1645 return -1;
1646 }
1647 } else {
1648 DEBUG("Removed existing \"/dev/ptmx\" file");
1649 }
1650
1651 /* Create dummy /dev/ptmx file as bind mountpoint for /dev/pts/ptmx. */
1652 ret = mknod("/dev/ptmx", S_IFREG | 0000, 0);
1653 if (ret < 0 && errno != EEXIST) {
1654 SYSERROR("Failed to create dummy \"/dev/ptmx\" file as bind mount target");
1655 return -1;
1656 }
1657 DEBUG("Created dummy \"/dev/ptmx\" file as bind mount target");
1658
1659 /* Fallback option: create symlink /dev/ptmx -> /dev/pts/ptmx */
1660 ret = mount("/dev/pts/ptmx", "/dev/ptmx", NULL, MS_BIND, NULL);
1661 if (!ret) {
1662 DEBUG("Bind mounted \"/dev/pts/ptmx\" to \"/dev/ptmx\"");
1663 return 0;
1664 } else {
1665 /* Fallthrough and try to create a symlink. */
1666 ERROR("Failed to bind mount \"/dev/pts/ptmx\" to \"/dev/ptmx\"");
1667 }
1668
1669 /* Remove the dummy /dev/ptmx file we created above. */
1670 ret = remove("/dev/ptmx");
1671 if (ret < 0) {
1672 SYSERROR("Failed to remove existing \"/dev/ptmx\"");
1673 return -1;
1674 }
1675
1676 /* Fallback option: Create symlink /dev/ptmx -> /dev/pts/ptmx. */
1677 ret = symlink("/dev/pts/ptmx", "/dev/ptmx");
1678 if (ret < 0) {
1679 SYSERROR("Failed to create symlink from \"/dev/ptmx\" to \"/dev/pts/ptmx\"");
1680 return -1;
1681 }
1682 DEBUG("Created symlink from \"/dev/ptmx\" to \"/dev/pts/ptmx\"");
1683
1684 return 0;
1685 }
1686
1687 static int setup_personality(int persona)
1688 {
1689 int ret;
1690
1691 #if HAVE_SYS_PERSONALITY_H
1692 if (persona == -1)
1693 return 0;
1694
1695 ret = personality(persona);
1696 if (ret < 0) {
1697 SYSERROR("Failed to set personality to \"0x%x\"", persona);
1698 return -1;
1699 }
1700
1701 INFO("Set personality to \"0x%x\"", persona);
1702 #endif
1703
1704 return 0;
1705 }
1706
1707 static int lxc_setup_dev_console(const struct lxc_rootfs *rootfs,
1708 const struct lxc_terminal *console)
1709 {
1710 int ret;
1711 char path[PATH_MAX];
1712 char *rootfs_path = rootfs->path ? rootfs->mount : "";
1713
1714 if (console->path && !strcmp(console->path, "none"))
1715 return 0;
1716
1717 ret = snprintf(path, sizeof(path), "%s/dev/console", rootfs_path);
1718 if (ret < 0 || (size_t)ret >= sizeof(path))
1719 return -1;
1720
1721 /* When we are asked to setup a console we remove any previous
1722 * /dev/console bind-mounts.
1723 */
1724 if (file_exists(path)) {
1725 ret = lxc_unstack_mountpoint(path, false);
1726 if (ret < 0) {
1727 SYSERROR("Failed to unmount \"%s\"", path);
1728 return -ret;
1729 } else {
1730 DEBUG("Cleared all (%d) mounts from \"%s\"", ret, path);
1731 }
1732 }
1733
1734 /* For unprivileged containers autodev or automounts will already have
1735 * taken care of creating /dev/console.
1736 */
1737 ret = mknod(path, S_IFREG | 0000, 0);
1738 if (ret < 0 && errno != EEXIST) {
1739 SYSERROR("Failed to create console");
1740 return -errno;
1741 }
1742
1743 ret = fchmod(console->slave, S_IXUSR | S_IXGRP);
1744 if (ret < 0) {
1745 SYSERROR("Failed to set mode \"0%o\" to \"%s\"",
1746 S_IXUSR | S_IXGRP, console->name);
1747 return -errno;
1748 }
1749
1750 ret = safe_mount(console->name, path, "none", MS_BIND, 0, rootfs_path);
1751 if (ret < 0) {
1752 ERROR("Failed to mount \"%s\" on \"%s\"", console->name, path);
1753 return -1;
1754 }
1755
1756 DEBUG("Mounted pts device \"%s\" onto \"%s\"", console->name, path);
1757 return 0;
1758 }
1759
1760 static int lxc_setup_ttydir_console(const struct lxc_rootfs *rootfs,
1761 const struct lxc_terminal *console,
1762 char *ttydir)
1763 {
1764 int ret;
1765 char path[PATH_MAX], lxcpath[PATH_MAX];
1766 char *rootfs_path = rootfs->path ? rootfs->mount : "";
1767
1768 if (console->path && !strcmp(console->path, "none"))
1769 return 0;
1770
1771 /* create rootfs/dev/<ttydir> directory */
1772 ret = snprintf(path, sizeof(path), "%s/dev/%s", rootfs_path, ttydir);
1773 if (ret < 0 || (size_t)ret >= sizeof(path))
1774 return -1;
1775
1776 ret = mkdir(path, 0755);
1777 if (ret && errno != EEXIST) {
1778 SYSERROR("Failed to create \"%s\"", path);
1779 return -errno;
1780 }
1781 DEBUG("Created directory for console and tty devices at \"%s\"", path);
1782
1783 ret = snprintf(lxcpath, sizeof(lxcpath), "%s/dev/%s/console", rootfs_path, ttydir);
1784 if (ret < 0 || (size_t)ret >= sizeof(lxcpath))
1785 return -1;
1786
1787 ret = mknod(lxcpath, S_IFREG | 0000, 0);
1788 if (ret < 0 && errno != EEXIST) {
1789 SYSERROR("Failed to create \"%s\"", lxcpath);
1790 return -errno;
1791 }
1792
1793 ret = snprintf(path, sizeof(path), "%s/dev/console", rootfs_path);
1794 if (ret < 0 || (size_t)ret >= sizeof(path))
1795 return -1;
1796
1797 if (file_exists(path)) {
1798 ret = lxc_unstack_mountpoint(path, false);
1799 if (ret < 0) {
1800 SYSERROR("Failed to unmount \"%s\"", path);
1801 return -ret;
1802 } else {
1803 DEBUG("Cleared all (%d) mounts from \"%s\"", ret, path);
1804 }
1805 }
1806
1807 ret = mknod(path, S_IFREG | 0000, 0);
1808 if (ret < 0 && errno != EEXIST) {
1809 SYSERROR("Failed to create console");
1810 return -errno;
1811 }
1812
1813 ret = fchmod(console->slave, S_IXUSR | S_IXGRP);
1814 if (ret < 0) {
1815 SYSERROR("Failed to set mode \"0%o\" to \"%s\"",
1816 S_IXUSR | S_IXGRP, console->name);
1817 return -errno;
1818 }
1819
1820 /* bind mount console->name to '/dev/<ttydir>/console' */
1821 ret = safe_mount(console->name, lxcpath, "none", MS_BIND, 0, rootfs_path);
1822 if (ret < 0) {
1823 ERROR("Failed to mount \"%s\" on \"%s\"", console->name, lxcpath);
1824 return -1;
1825 }
1826 DEBUG("Mounted \"%s\" onto \"%s\"", console->name, lxcpath);
1827
1828 /* bind mount '/dev/<ttydir>/console' to '/dev/console' */
1829 ret = safe_mount(lxcpath, path, "none", MS_BIND, 0, rootfs_path);
1830 if (ret < 0) {
1831 ERROR("Failed to mount \"%s\" on \"%s\"", console->name, lxcpath);
1832 return -1;
1833 }
1834 DEBUG("Mounted \"%s\" onto \"%s\"", console->name, lxcpath);
1835
1836 DEBUG("Console has been setup under \"%s\" and mounted to \"%s\"", lxcpath, path);
1837 return 0;
1838 }
1839
1840 static int lxc_setup_console(const struct lxc_rootfs *rootfs,
1841 const struct lxc_terminal *console, char *ttydir)
1842 {
1843
1844 if (!ttydir)
1845 return lxc_setup_dev_console(rootfs, console);
1846
1847 return lxc_setup_ttydir_console(rootfs, console, ttydir);
1848 }
1849
1850 static void parse_mntopt(char *opt, unsigned long *flags, char **data, size_t size)
1851 {
1852 struct mount_opt *mo;
1853
1854 /* If opt is found in mount_opt, set or clear flags.
1855 * Otherwise append it to data. */
1856
1857 for (mo = &mount_opt[0]; mo->name != NULL; mo++) {
1858 if (strncmp(opt, mo->name, strlen(mo->name)) == 0) {
1859 if (mo->clear)
1860 *flags &= ~mo->flag;
1861 else
1862 *flags |= mo->flag;
1863 return;
1864 }
1865 }
1866
1867 if (strlen(*data))
1868 (void)strlcat(*data, ",", size);
1869
1870 (void)strlcat(*data, opt, size);
1871 }
1872
1873 int parse_mntopts(const char *mntopts, unsigned long *mntflags, char **mntdata)
1874 {
1875 __do_free char *data = NULL, *s = NULL;
1876 char *p;
1877 size_t size;
1878
1879 *mntdata = NULL;
1880 *mntflags = 0L;
1881
1882 if (!mntopts)
1883 return 0;
1884
1885 s = strdup(mntopts);
1886 if (!s)
1887 return -1;
1888
1889 size = strlen(s) + 1;
1890 data = malloc(size);
1891 if (!data)
1892 return -1;
1893 *data = 0;
1894
1895 lxc_iterate_parts(p, s, ",")
1896 parse_mntopt(p, mntflags, &data, size);
1897
1898 if (*data)
1899 *mntdata = move_ptr(data);
1900
1901 return 0;
1902 }
1903
1904 static void parse_propagationopt(char *opt, unsigned long *flags)
1905 {
1906 struct mount_opt *mo;
1907
1908 /* If opt is found in propagation_opt, set or clear flags. */
1909 for (mo = &propagation_opt[0]; mo->name != NULL; mo++) {
1910 if (strncmp(opt, mo->name, strlen(mo->name)) != 0)
1911 continue;
1912
1913 if (mo->clear)
1914 *flags &= ~mo->flag;
1915 else
1916 *flags |= mo->flag;
1917
1918 return;
1919 }
1920 }
1921
1922 int parse_propagationopts(const char *mntopts, unsigned long *pflags)
1923 {
1924 __do_free char *s = NULL;
1925 char *p;
1926
1927 if (!mntopts)
1928 return 0;
1929
1930 s = strdup(mntopts);
1931 if (!s) {
1932 SYSERROR("Failed to allocate memory");
1933 return -ENOMEM;
1934 }
1935
1936 *pflags = 0L;
1937 lxc_iterate_parts(p, s, ",")
1938 parse_propagationopt(p, pflags);
1939
1940 return 0;
1941 }
1942
1943 static void null_endofword(char *word)
1944 {
1945 while (*word && *word != ' ' && *word != '\t')
1946 word++;
1947 *word = '\0';
1948 }
1949
1950 /* skip @nfields spaces in @src */
1951 static char *get_field(char *src, int nfields)
1952 {
1953 int i;
1954 char *p = src;
1955
1956 for (i = 0; i < nfields; i++) {
1957 while (*p && *p != ' ' && *p != '\t')
1958 p++;
1959
1960 if (!*p)
1961 break;
1962
1963 p++;
1964 }
1965
1966 return p;
1967 }
1968
1969 static int mount_entry(const char *fsname, const char *target,
1970 const char *fstype, unsigned long mountflags,
1971 unsigned long pflags, const char *data, bool optional,
1972 bool dev, bool relative, const char *rootfs)
1973 {
1974 int ret;
1975 char srcbuf[PATH_MAX];
1976 const char *srcpath = fsname;
1977 #ifdef HAVE_STATVFS
1978 struct statvfs sb;
1979 #endif
1980
1981 if (relative) {
1982 ret = snprintf(srcbuf, PATH_MAX, "%s/%s", rootfs ? rootfs : "/", fsname ? fsname : "");
1983 if (ret < 0 || ret >= PATH_MAX) {
1984 ERROR("source path is too long");
1985 return -1;
1986 }
1987 srcpath = srcbuf;
1988 }
1989
1990 ret = safe_mount(srcpath, target, fstype, mountflags & ~MS_REMOUNT, data,
1991 rootfs);
1992 if (ret < 0) {
1993 if (optional) {
1994 SYSINFO("Failed to mount \"%s\" on \"%s\" (optional)",
1995 srcpath ? srcpath : "(null)", target);
1996 return 0;
1997 }
1998
1999 SYSERROR("Failed to mount \"%s\" on \"%s\"",
2000 srcpath ? srcpath : "(null)", target);
2001 return -1;
2002 }
2003
2004 if ((mountflags & MS_REMOUNT) || (mountflags & MS_BIND)) {
2005 unsigned long rqd_flags = 0;
2006
2007 DEBUG("Remounting \"%s\" on \"%s\" to respect bind or remount "
2008 "options", srcpath ? srcpath : "(none)", target ? target : "(none)");
2009
2010 if (mountflags & MS_RDONLY)
2011 rqd_flags |= MS_RDONLY;
2012 #ifdef HAVE_STATVFS
2013 if (srcpath && statvfs(srcpath, &sb) == 0) {
2014 unsigned long required_flags = rqd_flags;
2015
2016 if (sb.f_flag & MS_NOSUID)
2017 required_flags |= MS_NOSUID;
2018
2019 if (sb.f_flag & MS_NODEV && !dev)
2020 required_flags |= MS_NODEV;
2021
2022 if (sb.f_flag & MS_RDONLY)
2023 required_flags |= MS_RDONLY;
2024
2025 if (sb.f_flag & MS_NOEXEC)
2026 required_flags |= MS_NOEXEC;
2027
2028 DEBUG("Flags for \"%s\" were %lu, required extra flags "
2029 "are %lu", srcpath, sb.f_flag, required_flags);
2030
2031 /* If this was a bind mount request, and required_flags
2032 * does not have any flags which are not already in
2033 * mountflags, then skip the remount.
2034 */
2035 if (!(mountflags & MS_REMOUNT)) {
2036 if (!(required_flags & ~mountflags) &&
2037 rqd_flags == 0) {
2038 DEBUG("Mountflags already were %lu, "
2039 "skipping remount", mountflags);
2040 goto skipremount;
2041 }
2042 }
2043
2044 mountflags |= required_flags;
2045 }
2046 #endif
2047
2048 ret = mount(srcpath, target, fstype, mountflags | MS_REMOUNT, data);
2049 if (ret < 0) {
2050 if (optional) {
2051 SYSINFO("Failed to mount \"%s\" on \"%s\" (optional)",
2052 srcpath ? srcpath : "(null)", target);
2053 return 0;
2054 }
2055
2056 SYSERROR("Failed to mount \"%s\" on \"%s\"",
2057 srcpath ? srcpath : "(null)", target);
2058 return -1;
2059 }
2060 }
2061
2062 #ifdef HAVE_STATVFS
2063 skipremount:
2064 #endif
2065 if (pflags) {
2066 ret = mount(NULL, target, NULL, pflags, NULL);
2067 if (ret < 0) {
2068 if (optional) {
2069 SYSINFO("Failed to change mount propagation "
2070 "for \"%s\" (optional)", target);
2071 return 0;
2072 } else {
2073 SYSERROR("Failed to change mount propagation "
2074 "for \"%s\" (optional)", target);
2075 return -1;
2076 }
2077 }
2078 DEBUG("Changed mount propagation for \"%s\"", target);
2079 }
2080
2081 DEBUG("Mounted \"%s\" on \"%s\" with filesystem type \"%s\"",
2082 srcpath ? srcpath : "(null)", target, fstype);
2083
2084 return 0;
2085 }
2086
2087 /* Remove "optional", "create=dir", and "create=file" from mntopt */
2088 static void cull_mntent_opt(struct mntent *mntent)
2089 {
2090 int i;
2091 char *list[] = {
2092 "create=dir",
2093 "create=file",
2094 "optional",
2095 "relative",
2096 NULL
2097 };
2098
2099 for (i = 0; list[i]; i++) {
2100 char *p, *p2;
2101
2102 p = strstr(mntent->mnt_opts, list[i]);
2103 if (!p)
2104 continue;
2105
2106 p2 = strchr(p, ',');
2107 if (!p2) {
2108 /* no more mntopts, so just chop it here */
2109 *p = '\0';
2110 continue;
2111 }
2112
2113 memmove(p, p2 + 1, strlen(p2 + 1) + 1);
2114 }
2115 }
2116
2117 static int mount_entry_create_dir_file(const struct mntent *mntent,
2118 const char *path,
2119 const struct lxc_rootfs *rootfs,
2120 const char *lxc_name, const char *lxc_path)
2121 {
2122 __do_free char *p1 = NULL;
2123 int ret;
2124 char *p2;
2125
2126 if (strncmp(mntent->mnt_type, "overlay", 7) == 0) {
2127 ret = ovl_mkdir(mntent, rootfs, lxc_name, lxc_path);
2128 if (ret < 0)
2129 return -1;
2130 }
2131
2132 if (hasmntopt(mntent, "create=dir")) {
2133 ret = mkdir_p(path, 0755);
2134 if (ret < 0 && errno != EEXIST) {
2135 SYSERROR("Failed to create directory \"%s\"", path);
2136 return -1;
2137 }
2138 }
2139
2140 if (!hasmntopt(mntent, "create=file"))
2141 return 0;
2142
2143 ret = access(path, F_OK);
2144 if (ret == 0)
2145 return 0;
2146
2147 p1 = strdup(path);
2148 if (!p1)
2149 return -1;
2150
2151 p2 = dirname(p1);
2152
2153 ret = mkdir_p(p2, 0755);
2154 if (ret < 0 && errno != EEXIST) {
2155 SYSERROR("Failed to create directory \"%s\"", path);
2156 return -1;
2157 }
2158
2159 ret = mknod(path, S_IFREG | 0000, 0);
2160 if (ret < 0 && errno != EEXIST)
2161 return -errno;
2162
2163 return 0;
2164 }
2165
2166 /* rootfs, lxc_name, and lxc_path can be NULL when the container is created
2167 * without a rootfs. */
2168 static inline int mount_entry_on_generic(struct mntent *mntent,
2169 const char *path,
2170 const struct lxc_rootfs *rootfs,
2171 const char *lxc_name,
2172 const char *lxc_path)
2173 {
2174 __do_free char *mntdata = NULL;
2175 int ret;
2176 unsigned long mntflags;
2177 bool dev, optional, relative;
2178 unsigned long pflags = 0;
2179 char *rootfs_path = NULL;
2180
2181 optional = hasmntopt(mntent, "optional") != NULL;
2182 dev = hasmntopt(mntent, "dev") != NULL;
2183 relative = hasmntopt(mntent, "relative") != NULL;
2184
2185 if (rootfs && rootfs->path)
2186 rootfs_path = rootfs->mount;
2187
2188 ret = mount_entry_create_dir_file(mntent, path, rootfs, lxc_name,
2189 lxc_path);
2190 if (ret < 0) {
2191 if (optional)
2192 return 0;
2193
2194 return -1;
2195 }
2196 cull_mntent_opt(mntent);
2197
2198 ret = parse_propagationopts(mntent->mnt_opts, &pflags);
2199 if (ret < 0)
2200 return -1;
2201
2202 ret = parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata);
2203 if (ret < 0)
2204 return -1;
2205
2206 ret = mount_entry(mntent->mnt_fsname, path, mntent->mnt_type, mntflags,
2207 pflags, mntdata, optional, dev, relative, rootfs_path);
2208
2209 return ret;
2210 }
2211
2212 static inline int mount_entry_on_systemfs(struct mntent *mntent)
2213 {
2214 int ret;
2215 char path[PATH_MAX];
2216
2217 /* For containers created without a rootfs all mounts are treated as
2218 * absolute paths starting at / on the host.
2219 */
2220 if (mntent->mnt_dir[0] != '/')
2221 ret = snprintf(path, sizeof(path), "/%s", mntent->mnt_dir);
2222 else
2223 ret = snprintf(path, sizeof(path), "%s", mntent->mnt_dir);
2224 if (ret < 0 || ret >= sizeof(path))
2225 return -1;
2226
2227 return mount_entry_on_generic(mntent, path, NULL, NULL, NULL);
2228 }
2229
2230 static int mount_entry_on_absolute_rootfs(struct mntent *mntent,
2231 const struct lxc_rootfs *rootfs,
2232 const char *lxc_name,
2233 const char *lxc_path)
2234 {
2235 int offset;
2236 char *aux;
2237 const char *lxcpath;
2238 char path[PATH_MAX];
2239 int ret = 0;
2240
2241 lxcpath = lxc_global_config_value("lxc.lxcpath");
2242 if (!lxcpath)
2243 return -1;
2244
2245 /* If rootfs->path is a blockdev path, allow container fstab to use
2246 * <lxcpath>/<name>/rootfs" as the target prefix.
2247 */
2248 ret = snprintf(path, PATH_MAX, "%s/%s/rootfs", lxcpath, lxc_name);
2249 if (ret < 0 || ret >= PATH_MAX)
2250 goto skipvarlib;
2251
2252 aux = strstr(mntent->mnt_dir, path);
2253 if (aux) {
2254 offset = strlen(path);
2255 goto skipabs;
2256 }
2257
2258 skipvarlib:
2259 aux = strstr(mntent->mnt_dir, rootfs->path);
2260 if (!aux) {
2261 WARN("Ignoring mount point \"%s\"", mntent->mnt_dir);
2262 return ret;
2263 }
2264 offset = strlen(rootfs->path);
2265
2266 skipabs:
2267 ret = snprintf(path, PATH_MAX, "%s/%s", rootfs->mount, aux + offset);
2268 if (ret < 0 || ret >= PATH_MAX)
2269 return -1;
2270
2271 return mount_entry_on_generic(mntent, path, rootfs, lxc_name, lxc_path);
2272 }
2273
2274 static int mount_entry_on_relative_rootfs(struct mntent *mntent,
2275 const struct lxc_rootfs *rootfs,
2276 const char *lxc_name,
2277 const char *lxc_path)
2278 {
2279 int ret;
2280 char path[PATH_MAX];
2281
2282 /* relative to root mount point */
2283 ret = snprintf(path, sizeof(path), "%s/%s", rootfs->mount, mntent->mnt_dir);
2284 if (ret < 0 || (size_t)ret >= sizeof(path))
2285 return -1;
2286
2287 return mount_entry_on_generic(mntent, path, rootfs, lxc_name, lxc_path);
2288 }
2289
2290 static int mount_file_entries(const struct lxc_conf *conf,
2291 const struct lxc_rootfs *rootfs, FILE *file,
2292 const char *lxc_name, const char *lxc_path)
2293 {
2294 char buf[PATH_MAX];
2295 struct mntent mntent;
2296
2297 while (getmntent_r(file, &mntent, buf, sizeof(buf))) {
2298 int ret;
2299
2300 if (!rootfs->path)
2301 ret = mount_entry_on_systemfs(&mntent);
2302 else if (mntent.mnt_dir[0] != '/')
2303 ret = mount_entry_on_relative_rootfs(&mntent, rootfs,
2304 lxc_name, lxc_path);
2305 else
2306 ret = mount_entry_on_absolute_rootfs(&mntent, rootfs,
2307 lxc_name, lxc_path);
2308 if (ret < 0)
2309 return -1;
2310 }
2311
2312 if (!feof(file) || ferror(file)) {
2313 ERROR("Failed to parse mount entries");
2314 return -1;
2315 }
2316
2317 return 0;
2318 }
2319
2320 static int setup_mount(const struct lxc_conf *conf,
2321 const struct lxc_rootfs *rootfs, const char *fstab,
2322 const char *lxc_name, const char *lxc_path)
2323 {
2324 FILE *f;
2325 int ret;
2326
2327 if (!fstab)
2328 return 0;
2329
2330 f = setmntent(fstab, "r");
2331 if (!f) {
2332 SYSERROR("Failed to open \"%s\"", fstab);
2333 return -1;
2334 }
2335
2336 ret = mount_file_entries(conf, rootfs, f, lxc_name, lxc_path);
2337 if (ret < 0)
2338 ERROR("Failed to set up mount entries");
2339
2340 endmntent(f);
2341 return ret;
2342 }
2343
2344 /*
2345 * In order for nested containers to be able to mount /proc and /sys they need
2346 * to see a "pure" proc and sysfs mount points with nothing mounted on top
2347 * (like lxcfs).
2348 * For this we provide proc and sysfs in /dev/.lxc/{proc,sys} while using an
2349 * apparmor rule to deny access to them. This is mostly for convenience: The
2350 * container's root user can mount them anyway and thus has access to the two
2351 * file systems. But a non-root user in the container should not be allowed to
2352 * access them as a side effect without explicitly allowing it.
2353 */
2354 static const char nesting_helpers[] =
2355 "proc dev/.lxc/proc proc create=dir,optional 0 0\n"
2356 "sys dev/.lxc/sys sysfs create=dir,optional 0 0\n";
2357
2358 FILE *make_anonymous_mount_file(struct lxc_list *mount,
2359 bool include_nesting_helpers)
2360 {
2361 __do_close_prot_errno int fd = -EBADF;
2362 int ret;
2363 char *mount_entry;
2364 struct lxc_list *iterator;
2365
2366 fd = memfd_create(".lxc_mount_file", MFD_CLOEXEC);
2367 if (fd < 0) {
2368 char template[] = P_tmpdir "/.lxc_mount_file_XXXXXX";
2369
2370 if (errno != ENOSYS)
2371 return NULL;
2372
2373 fd = lxc_make_tmpfile(template, true);
2374 if (fd < 0) {
2375 SYSERROR("Could not create temporary mount file");
2376 return NULL;
2377 }
2378
2379 TRACE("Created temporary mount file");
2380 }
2381
2382 lxc_list_for_each (iterator, mount) {
2383 size_t len;
2384
2385 mount_entry = iterator->elem;
2386 len = strlen(mount_entry);
2387
2388 ret = lxc_write_nointr(fd, mount_entry, len);
2389 if (ret != len)
2390 return NULL;
2391
2392 ret = lxc_write_nointr(fd, "\n", 1);
2393 if (ret != 1)
2394 return NULL;
2395 }
2396
2397 if (include_nesting_helpers) {
2398 ret = lxc_write_nointr(fd, nesting_helpers,
2399 STRARRAYLEN(nesting_helpers));
2400 if (ret != STRARRAYLEN(nesting_helpers))
2401 return NULL;
2402 }
2403
2404 ret = lseek(fd, 0, SEEK_SET);
2405 if (ret < 0)
2406 return NULL;
2407
2408 return fdopen(move_fd(fd), "r+");
2409 }
2410
2411 static int setup_mount_entries(const struct lxc_conf *conf,
2412 const struct lxc_rootfs *rootfs,
2413 struct lxc_list *mount, const char *lxc_name,
2414 const char *lxc_path)
2415 {
2416 __do_fclose FILE *f = NULL;
2417
2418 f = make_anonymous_mount_file(mount, conf->lsm_aa_allow_nesting);
2419 if (!f)
2420 return -1;
2421
2422 return mount_file_entries(conf, rootfs, f, lxc_name, lxc_path);
2423 }
2424
2425 static int parse_cap(const char *cap)
2426 {
2427 size_t i;
2428 int capid = -1;
2429 size_t end = sizeof(caps_opt) / sizeof(caps_opt[0]);
2430 char *ptr = NULL;
2431
2432 if (strcmp(cap, "none") == 0)
2433 return -2;
2434
2435 for (i = 0; i < end; i++) {
2436 if (strcmp(cap, caps_opt[i].name))
2437 continue;
2438
2439 capid = caps_opt[i].value;
2440 break;
2441 }
2442
2443 if (capid < 0) {
2444 /* Try to see if it's numeric, so the user may specify
2445 * capabilities that the running kernel knows about but we
2446 * don't
2447 */
2448 errno = 0;
2449 capid = strtol(cap, &ptr, 10);
2450 if (!ptr || *ptr != '\0' || errno != 0)
2451 /* not a valid number */
2452 capid = -1;
2453 else if (capid > lxc_caps_last_cap())
2454 /* we have a number but it's not a valid
2455 * capability */
2456 capid = -1;
2457 }
2458
2459 return capid;
2460 }
2461
2462 int in_caplist(int cap, struct lxc_list *caps)
2463 {
2464 int capid;
2465 struct lxc_list *iterator;
2466
2467 lxc_list_for_each (iterator, caps) {
2468 capid = parse_cap(iterator->elem);
2469 if (capid == cap)
2470 return 1;
2471 }
2472
2473 return 0;
2474 }
2475
2476 static int setup_caps(struct lxc_list *caps)
2477 {
2478 int capid;
2479 char *drop_entry;
2480 struct lxc_list *iterator;
2481
2482 lxc_list_for_each (iterator, caps) {
2483 int ret;
2484
2485 drop_entry = iterator->elem;
2486
2487 capid = parse_cap(drop_entry);
2488 if (capid < 0) {
2489 ERROR("unknown capability %s", drop_entry);
2490 return -1;
2491 }
2492
2493 ret = prctl(PR_CAPBSET_DROP, prctl_arg(capid), prctl_arg(0),
2494 prctl_arg(0), prctl_arg(0));
2495 if (ret < 0) {
2496 SYSERROR("Failed to remove %s capability", drop_entry);
2497 return -1;
2498 }
2499 DEBUG("Dropped %s (%d) capability", drop_entry, capid);
2500 }
2501
2502 DEBUG("Capabilities have been setup");
2503 return 0;
2504 }
2505
2506 static int dropcaps_except(struct lxc_list *caps)
2507 {
2508 __do_free int *caplist = NULL;
2509 int i, capid, numcaps;
2510 char *keep_entry;
2511 struct lxc_list *iterator;
2512
2513 numcaps = lxc_caps_last_cap() + 1;
2514 if (numcaps <= 0 || numcaps > 200)
2515 return -1;
2516 TRACE("Found %d capabilities", numcaps);
2517
2518 /* caplist[i] is 1 if we keep capability i */
2519 caplist = must_realloc(NULL, numcaps * sizeof(int));
2520 memset(caplist, 0, numcaps * sizeof(int));
2521
2522 lxc_list_for_each (iterator, caps) {
2523 keep_entry = iterator->elem;
2524
2525 capid = parse_cap(keep_entry);
2526 if (capid == -2)
2527 continue;
2528
2529 if (capid < 0) {
2530 ERROR("Unknown capability %s", keep_entry);
2531 return -1;
2532 }
2533
2534 DEBUG("Keep capability %s (%d)", keep_entry, capid);
2535 caplist[capid] = 1;
2536 }
2537
2538 for (i = 0; i < numcaps; i++) {
2539 int ret;
2540
2541 if (caplist[i])
2542 continue;
2543
2544 ret = prctl(PR_CAPBSET_DROP, prctl_arg(i), prctl_arg(0),
2545 prctl_arg(0), prctl_arg(0));
2546 if (ret < 0) {
2547 SYSERROR("Failed to remove capability %d", i);
2548 return -1;
2549 }
2550 }
2551
2552 DEBUG("Capabilities have been setup");
2553 return 0;
2554 }
2555
2556 static int parse_resource(const char *res)
2557 {
2558 int ret;
2559 size_t i;
2560 int resid = -1;
2561
2562 for (i = 0; i < sizeof(limit_opt) / sizeof(limit_opt[0]); ++i)
2563 if (strcmp(res, limit_opt[i].name) == 0)
2564 return limit_opt[i].value;
2565
2566 /* Try to see if it's numeric, so the user may specify
2567 * resources that the running kernel knows about but
2568 * we don't.
2569 */
2570 ret = lxc_safe_int(res, &resid);
2571 if (ret < 0)
2572 return -1;
2573
2574 return resid;
2575 }
2576
2577 int setup_resource_limits(struct lxc_list *limits, pid_t pid)
2578 {
2579 int resid;
2580 struct lxc_list *it;
2581 struct lxc_limit *lim;
2582
2583 lxc_list_for_each (it, limits) {
2584 lim = it->elem;
2585
2586 resid = parse_resource(lim->resource);
2587 if (resid < 0) {
2588 ERROR("Unknown resource %s", lim->resource);
2589 return -1;
2590 }
2591
2592 #if HAVE_PRLIMIT || HAVE_PRLIMIT64
2593 if (prlimit(pid, resid, &lim->limit, NULL) != 0) {
2594 SYSERROR("Failed to set limit %s", lim->resource);
2595 return -1;
2596 }
2597
2598 TRACE("Setup \"%s\" limit", lim->resource);
2599 #else
2600 ERROR("Cannot set limit \"%s\" as prlimit is missing", lim->resource);
2601 return -1;
2602 #endif
2603 }
2604
2605 return 0;
2606 }
2607
2608 int setup_sysctl_parameters(struct lxc_list *sysctls)
2609 {
2610 __do_free char *tmp = NULL;
2611 struct lxc_list *it;
2612 struct lxc_sysctl *elem;
2613 int ret = 0;
2614 char filename[PATH_MAX] = {0};
2615
2616 lxc_list_for_each (it, sysctls) {
2617 elem = it->elem;
2618 tmp = lxc_string_replace(".", "/", elem->key);
2619 if (!tmp) {
2620 ERROR("Failed to replace key %s", elem->key);
2621 return -1;
2622 }
2623
2624 ret = snprintf(filename, sizeof(filename), "/proc/sys/%s", tmp);
2625 if (ret < 0 || (size_t)ret >= sizeof(filename)) {
2626 ERROR("Error setting up sysctl parameters path");
2627 return -1;
2628 }
2629
2630 ret = lxc_write_to_file(filename, elem->value,
2631 strlen(elem->value), false, 0666);
2632 if (ret < 0) {
2633 SYSERROR("Failed to setup sysctl parameters %s to %s",
2634 elem->key, elem->value);
2635 return -1;
2636 }
2637 }
2638
2639 return 0;
2640 }
2641
2642 int setup_proc_filesystem(struct lxc_list *procs, pid_t pid)
2643 {
2644 __do_free char *tmp = NULL;
2645 struct lxc_list *it;
2646 struct lxc_proc *elem;
2647 int ret = 0;
2648 char filename[PATH_MAX] = {0};
2649
2650 lxc_list_for_each (it, procs) {
2651 elem = it->elem;
2652 tmp = lxc_string_replace(".", "/", elem->filename);
2653 if (!tmp) {
2654 ERROR("Failed to replace key %s", elem->filename);
2655 return -1;
2656 }
2657
2658 ret = snprintf(filename, sizeof(filename), "/proc/%d/%s", pid, tmp);
2659 if (ret < 0 || (size_t)ret >= sizeof(filename)) {
2660 ERROR("Error setting up proc filesystem path");
2661 return -1;
2662 }
2663
2664 ret = lxc_write_to_file(filename, elem->value,
2665 strlen(elem->value), false, 0666);
2666 if (ret < 0) {
2667 SYSERROR("Failed to setup proc filesystem %s to %s",
2668 elem->filename, elem->value);
2669 return -1;
2670 }
2671 }
2672
2673 return 0;
2674 }
2675
2676 static char *default_rootfs_mount = LXCROOTFSMOUNT;
2677
2678 struct lxc_conf *lxc_conf_init(void)
2679 {
2680 int i;
2681 struct lxc_conf *new;
2682
2683 new = malloc(sizeof(*new));
2684 if (!new)
2685 return NULL;
2686 memset(new, 0, sizeof(*new));
2687
2688 new->loglevel = LXC_LOG_LEVEL_NOTSET;
2689 new->personality = -1;
2690 new->autodev = 1;
2691 new->console.buffer_size = 0;
2692 new->console.log_path = NULL;
2693 new->console.log_fd = -1;
2694 new->console.log_size = 0;
2695 new->console.path = NULL;
2696 new->console.peer = -1;
2697 new->console.proxy.busy = -1;
2698 new->console.proxy.master = -1;
2699 new->console.proxy.slave = -1;
2700 new->console.master = -1;
2701 new->console.slave = -1;
2702 new->console.name[0] = '\0';
2703 memset(&new->console.ringbuf, 0, sizeof(struct lxc_ringbuf));
2704 new->maincmd_fd = -1;
2705 new->monitor_signal_pdeath = SIGKILL;
2706 new->nbd_idx = -1;
2707 new->rootfs.mount = strdup(default_rootfs_mount);
2708 if (!new->rootfs.mount) {
2709 free(new);
2710 return NULL;
2711 }
2712 new->rootfs.managed = true;
2713 new->logfd = -1;
2714 lxc_list_init(&new->cgroup);
2715 lxc_list_init(&new->cgroup2);
2716 lxc_list_init(&new->network);
2717 lxc_list_init(&new->mount_list);
2718 lxc_list_init(&new->caps);
2719 lxc_list_init(&new->keepcaps);
2720 lxc_list_init(&new->id_map);
2721 new->root_nsuid_map = NULL;
2722 new->root_nsgid_map = NULL;
2723 lxc_list_init(&new->includes);
2724 lxc_list_init(&new->aliens);
2725 lxc_list_init(&new->environment);
2726 lxc_list_init(&new->limits);
2727 lxc_list_init(&new->sysctls);
2728 lxc_list_init(&new->procs);
2729 new->hooks_version = 0;
2730 for (i = 0; i < NUM_LXC_HOOKS; i++)
2731 lxc_list_init(&new->hooks[i]);
2732 lxc_list_init(&new->groups);
2733 lxc_list_init(&new->state_clients);
2734 new->lsm_aa_profile = NULL;
2735 lxc_list_init(&new->lsm_aa_raw);
2736 new->lsm_se_context = NULL;
2737 new->tmp_umount_proc = false;
2738 new->tmp_umount_proc = 0;
2739 new->shmount.path_host = NULL;
2740 new->shmount.path_cont = NULL;
2741
2742 /* if running in a new user namespace, init and COMMAND
2743 * default to running as UID/GID 0 when using lxc-execute */
2744 new->init_uid = 0;
2745 new->init_gid = 0;
2746 memset(&new->cgroup_meta, 0, sizeof(struct lxc_cgroup));
2747 memset(&new->ns_share, 0, sizeof(char *) * LXC_NS_MAX);
2748
2749 return new;
2750 }
2751
2752 int write_id_mapping(enum idtype idtype, pid_t pid, const char *buf,
2753 size_t buf_size)
2754 {
2755 __do_close_prot_errno int fd;
2756 int ret;
2757 char path[PATH_MAX];
2758
2759 if (geteuid() != 0 && idtype == ID_TYPE_GID) {
2760 __do_close_prot_errno int setgroups_fd = -EBADF;
2761
2762 ret = snprintf(path, PATH_MAX, "/proc/%d/setgroups", pid);
2763 if (ret < 0 || ret >= PATH_MAX)
2764 return -E2BIG;
2765
2766 setgroups_fd = open(path, O_WRONLY);
2767 if (setgroups_fd < 0 && errno != ENOENT) {
2768 SYSERROR("Failed to open \"%s\"", path);
2769 return -1;
2770 }
2771
2772 if (setgroups_fd >= 0) {
2773 ret = lxc_write_nointr(setgroups_fd, "deny\n",
2774 STRLITERALLEN("deny\n"));
2775 if (ret != STRLITERALLEN("deny\n")) {
2776 SYSERROR("Failed to write \"deny\" to \"/proc/%d/setgroups\"", pid);
2777 return -1;
2778 }
2779 TRACE("Wrote \"deny\" to \"/proc/%d/setgroups\"", pid);
2780 }
2781 }
2782
2783 ret = snprintf(path, PATH_MAX, "/proc/%d/%cid_map", pid,
2784 idtype == ID_TYPE_UID ? 'u' : 'g');
2785 if (ret < 0 || ret >= PATH_MAX)
2786 return -E2BIG;
2787
2788 fd = open(path, O_WRONLY);
2789 if (fd < 0) {
2790 SYSERROR("Failed to open \"%s\"", path);
2791 return -1;
2792 }
2793
2794 ret = lxc_write_nointr(fd, buf, buf_size);
2795 if (ret != buf_size) {
2796 SYSERROR("Failed to write %cid mapping to \"%s\"",
2797 idtype == ID_TYPE_UID ? 'u' : 'g', path);
2798 return -1;
2799 }
2800
2801 return 0;
2802 }
2803
2804 /* Check whether a binary exist and has either CAP_SETUID, CAP_SETGID or both.
2805 *
2806 * @return 1 if functional binary was found
2807 * @return 0 if binary exists but is lacking privilege
2808 * @return -ENOENT if binary does not exist
2809 * @return -EINVAL if cap to check is neither CAP_SETUID nor CAP_SETGID
2810 */
2811 static int idmaptool_on_path_and_privileged(const char *binary, cap_value_t cap)
2812 {
2813 __do_free char *path = NULL;
2814 int ret;
2815 struct stat st;
2816
2817 errno = EINVAL;
2818 if (cap != CAP_SETUID && cap != CAP_SETGID)
2819 return -1;
2820
2821 errno = ENOENT;
2822 path = on_path(binary, NULL);
2823 if (!path)
2824 return -1;
2825
2826 ret = stat(path, &st);
2827 if (ret < 0)
2828 return -1;
2829
2830 /* Check if the binary is setuid. */
2831 if (st.st_mode & S_ISUID) {
2832 DEBUG("The binary \"%s\" does have the setuid bit set", path);
2833 return 1;
2834 }
2835
2836 #if HAVE_LIBCAP && LIBCAP_SUPPORTS_FILE_CAPABILITIES
2837 /* Check if it has the CAP_SETUID capability. */
2838 if ((cap & CAP_SETUID) &&
2839 lxc_file_cap_is_set(path, CAP_SETUID, CAP_EFFECTIVE) &&
2840 lxc_file_cap_is_set(path, CAP_SETUID, CAP_PERMITTED)) {
2841 DEBUG("The binary \"%s\" has CAP_SETUID in its CAP_EFFECTIVE "
2842 "and CAP_PERMITTED sets", path);
2843 return 1;
2844 }
2845
2846 /* Check if it has the CAP_SETGID capability. */
2847 if ((cap & CAP_SETGID) &&
2848 lxc_file_cap_is_set(path, CAP_SETGID, CAP_EFFECTIVE) &&
2849 lxc_file_cap_is_set(path, CAP_SETGID, CAP_PERMITTED)) {
2850 DEBUG("The binary \"%s\" has CAP_SETGID in its CAP_EFFECTIVE "
2851 "and CAP_PERMITTED sets", path);
2852 return 1;
2853 }
2854 #else
2855 /* If we cannot check for file capabilities we need to give the benefit
2856 * of the doubt. Otherwise we might fail even though all the necessary
2857 * file capabilities are set.
2858 */
2859 DEBUG("Cannot check for file capabilities as full capability support is "
2860 "missing. Manual intervention needed");
2861 #endif
2862
2863 return 1;
2864 }
2865
2866 int lxc_map_ids_exec_wrapper(void *args)
2867 {
2868 execl("/bin/sh", "sh", "-c", (char *)args, (char *)NULL);
2869 return -1;
2870 }
2871
2872 int lxc_map_ids(struct lxc_list *idmap, pid_t pid)
2873 {
2874 int fill, left;
2875 char u_or_g;
2876 char *pos;
2877 char cmd_output[PATH_MAX];
2878 struct id_map *map;
2879 struct lxc_list *iterator;
2880 enum idtype type;
2881 /* strlen("new@idmap") = 9
2882 * +
2883 * strlen(" ") = 1
2884 * +
2885 * INTTYPE_TO_STRLEN(uint32_t)
2886 * +
2887 * strlen(" ") = 1
2888 *
2889 * We add some additional space to make sure that we really have
2890 * LXC_IDMAPLEN bytes available for our the {g,u]id mapping.
2891 */
2892 int ret = 0, gidmap = 0, uidmap = 0;
2893 char mapbuf[9 + 1 + INTTYPE_TO_STRLEN(uint32_t) + 1 + LXC_IDMAPLEN] = {0};
2894 bool had_entry = false, use_shadow = false;
2895 int hostuid, hostgid;
2896
2897 hostuid = geteuid();
2898 hostgid = getegid();
2899
2900 /* If new{g,u}idmap exists, that is, if shadow is handing out subuid
2901 * ranges, then insist that root also reserve ranges in subuid. This
2902 * will protected it by preventing another user from being handed the
2903 * range by shadow.
2904 */
2905 uidmap = idmaptool_on_path_and_privileged("newuidmap", CAP_SETUID);
2906 if (uidmap == -ENOENT)
2907 WARN("newuidmap binary is missing");
2908 else if (!uidmap)
2909 WARN("newuidmap is lacking necessary privileges");
2910
2911 gidmap = idmaptool_on_path_and_privileged("newgidmap", CAP_SETGID);
2912 if (gidmap == -ENOENT)
2913 WARN("newgidmap binary is missing");
2914 else if (!gidmap)
2915 WARN("newgidmap is lacking necessary privileges");
2916
2917 if (uidmap > 0 && gidmap > 0) {
2918 DEBUG("Functional newuidmap and newgidmap binary found");
2919 use_shadow = true;
2920 } else {
2921 /* In case unprivileged users run application containers via
2922 * execute() or a start*() there are valid cases where they may
2923 * only want to map their own {g,u}id. Let's not block them from
2924 * doing so by requiring geteuid() == 0.
2925 */
2926 DEBUG("No newuidmap and newgidmap binary found. Trying to "
2927 "write directly with euid %d", hostuid);
2928 }
2929
2930 /* Check if we really need to use newuidmap and newgidmap.
2931 * If the user is only remapping his own {g,u}id, we don't need it.
2932 */
2933 if (use_shadow && lxc_list_len(idmap) == 2) {
2934 use_shadow = false;
2935 lxc_list_for_each(iterator, idmap) {
2936 map = iterator->elem;
2937 if (map->idtype == ID_TYPE_UID && map->range == 1 &&
2938 map->nsid == hostuid && map->hostid == hostuid)
2939 continue;
2940 if (map->idtype == ID_TYPE_GID && map->range == 1 &&
2941 map->nsid == hostgid && map->hostid == hostgid)
2942 continue;
2943 use_shadow = true;
2944 break;
2945 }
2946 }
2947
2948 for (type = ID_TYPE_UID, u_or_g = 'u'; type <= ID_TYPE_GID;
2949 type++, u_or_g = 'g') {
2950 pos = mapbuf;
2951
2952 if (use_shadow)
2953 pos += sprintf(mapbuf, "new%cidmap %d", u_or_g, pid);
2954
2955 lxc_list_for_each(iterator, idmap) {
2956 map = iterator->elem;
2957 if (map->idtype != type)
2958 continue;
2959
2960 had_entry = true;
2961
2962 left = LXC_IDMAPLEN - (pos - mapbuf);
2963 fill = snprintf(pos, left, "%s%lu %lu %lu%s",
2964 use_shadow ? " " : "", map->nsid,
2965 map->hostid, map->range,
2966 use_shadow ? "" : "\n");
2967 if (fill <= 0 || fill >= left) {
2968 /* The kernel only takes <= 4k for writes to
2969 * /proc/<pid>/{g,u}id_map
2970 */
2971 SYSERROR("Too many %cid mappings defined", u_or_g);
2972 return -1;
2973 }
2974
2975 pos += fill;
2976 }
2977 if (!had_entry)
2978 continue;
2979
2980 /* Try to catch the output of new{g,u}idmap to make debugging
2981 * easier.
2982 */
2983 if (use_shadow) {
2984 ret = run_command(cmd_output, sizeof(cmd_output),
2985 lxc_map_ids_exec_wrapper,
2986 (void *)mapbuf);
2987 if (ret < 0) {
2988 ERROR("new%cidmap failed to write mapping \"%s\": %s",
2989 u_or_g, cmd_output, mapbuf);
2990 return -1;
2991 }
2992 TRACE("new%cidmap wrote mapping \"%s\"", u_or_g, mapbuf);
2993 } else {
2994 ret = write_id_mapping(type, pid, mapbuf, pos - mapbuf);
2995 if (ret < 0) {
2996 ERROR("Failed to write mapping: %s", mapbuf);
2997 return -1;
2998 }
2999 TRACE("Wrote mapping \"%s\"", mapbuf);
3000 }
3001
3002 memset(mapbuf, 0, sizeof(mapbuf));
3003 }
3004
3005 return 0;
3006 }
3007
3008 /* Return the host uid/gid to which the container root is mapped in val.
3009 * Return true if id was found, false otherwise.
3010 */
3011 bool get_mapped_rootid(struct lxc_conf *conf, enum idtype idtype,
3012 unsigned long *val)
3013 {
3014 unsigned nsid;
3015 struct id_map *map;
3016 struct lxc_list *it;
3017
3018 if (idtype == ID_TYPE_UID)
3019 nsid = (conf->root_nsuid_map != NULL) ? 0 : conf->init_uid;
3020 else
3021 nsid = (conf->root_nsgid_map != NULL) ? 0 : conf->init_gid;
3022
3023 lxc_list_for_each (it, &conf->id_map) {
3024 map = it->elem;
3025 if (map->idtype != idtype)
3026 continue;
3027 if (map->nsid != nsid)
3028 continue;
3029 *val = map->hostid;
3030 return true;
3031 }
3032
3033 return false;
3034 }
3035
3036 int mapped_hostid(unsigned id, struct lxc_conf *conf, enum idtype idtype)
3037 {
3038 struct id_map *map;
3039 struct lxc_list *it;
3040
3041 lxc_list_for_each (it, &conf->id_map) {
3042 map = it->elem;
3043 if (map->idtype != idtype)
3044 continue;
3045
3046 if (id >= map->hostid && id < map->hostid + map->range)
3047 return (id - map->hostid) + map->nsid;
3048 }
3049
3050 return -1;
3051 }
3052
3053 int find_unmapped_nsid(struct lxc_conf *conf, enum idtype idtype)
3054 {
3055 struct id_map *map;
3056 struct lxc_list *it;
3057 unsigned int freeid = 0;
3058
3059 again:
3060 lxc_list_for_each (it, &conf->id_map) {
3061 map = it->elem;
3062 if (map->idtype != idtype)
3063 continue;
3064
3065 if (freeid >= map->nsid && freeid < map->nsid + map->range) {
3066 freeid = map->nsid + map->range;
3067 goto again;
3068 }
3069 }
3070
3071 return freeid;
3072 }
3073
3074 int chown_mapped_root_exec_wrapper(void *args)
3075 {
3076 execvp("lxc-usernsexec", args);
3077 return -1;
3078 }
3079
3080 /* chown_mapped_root: for an unprivileged user with uid/gid X to
3081 * chown a dir to subuid/subgid Y, he needs to run chown as root
3082 * in a userns where nsid 0 is mapped to hostuid/hostgid Y, and
3083 * nsid Y is mapped to hostuid/hostgid X. That way, the container
3084 * root is privileged with respect to hostuid/hostgid X, allowing
3085 * him to do the chown.
3086 */
3087 int chown_mapped_root(const char *path, struct lxc_conf *conf)
3088 {
3089 uid_t rootuid, rootgid;
3090 unsigned long val;
3091 int hostuid, hostgid, ret;
3092 struct stat sb;
3093 char map1[100], map2[100], map3[100], map4[100], map5[100];
3094 char ugid[100];
3095 const char *args1[] = {"lxc-usernsexec",
3096 "-m", map1,
3097 "-m", map2,
3098 "-m", map3,
3099 "-m", map5,
3100 "--", "chown", ugid, path,
3101 NULL};
3102 const char *args2[] = {"lxc-usernsexec",
3103 "-m", map1,
3104 "-m", map2,
3105 "-m", map3,
3106 "-m", map4,
3107 "-m", map5,
3108 "--", "chown", ugid, path,
3109 NULL};
3110 char cmd_output[PATH_MAX];
3111
3112 hostuid = geteuid();
3113 hostgid = getegid();
3114
3115 if (!get_mapped_rootid(conf, ID_TYPE_UID, &val)) {
3116 ERROR("No uid mapping for container root");
3117 return -1;
3118 }
3119 rootuid = (uid_t)val;
3120
3121 if (!get_mapped_rootid(conf, ID_TYPE_GID, &val)) {
3122 ERROR("No gid mapping for container root");
3123 return -1;
3124 }
3125 rootgid = (gid_t)val;
3126
3127 if (hostuid == 0) {
3128 if (chown(path, rootuid, rootgid) < 0) {
3129 ERROR("Error chowning %s", path);
3130 return -1;
3131 }
3132
3133 return 0;
3134 }
3135
3136 if (rootuid == hostuid) {
3137 /* nothing to do */
3138 INFO("Container root is our uid; no need to chown");
3139 return 0;
3140 }
3141
3142 /* save the current gid of "path" */
3143 if (stat(path, &sb) < 0) {
3144 ERROR("Error stat %s", path);
3145 return -1;
3146 }
3147
3148 /* Update the path argument in case this was overlayfs. */
3149 args1[sizeof(args1) / sizeof(args1[0]) - 2] = path;
3150 args2[sizeof(args2) / sizeof(args2[0]) - 2] = path;
3151
3152 /*
3153 * A file has to be group-owned by a gid mapped into the
3154 * container, or the container won't be privileged over it.
3155 */
3156 DEBUG("trying to chown \"%s\" to %d", path, hostgid);
3157 if (sb.st_uid == hostuid &&
3158 mapped_hostid(sb.st_gid, conf, ID_TYPE_GID) < 0 &&
3159 chown(path, -1, hostgid) < 0) {
3160 ERROR("Failed chgrping %s", path);
3161 return -1;
3162 }
3163
3164 /* "u:0:rootuid:1" */
3165 ret = snprintf(map1, 100, "u:0:%d:1", rootuid);
3166 if (ret < 0 || ret >= 100) {
3167 ERROR("Error uid printing map string");
3168 return -1;
3169 }
3170
3171 /* "u:hostuid:hostuid:1" */
3172 ret = snprintf(map2, 100, "u:%d:%d:1", hostuid, hostuid);
3173 if (ret < 0 || ret >= 100) {
3174 ERROR("Error uid printing map string");
3175 return -1;
3176 }
3177
3178 /* "g:0:rootgid:1" */
3179 ret = snprintf(map3, 100, "g:0:%d:1", rootgid);
3180 if (ret < 0 || ret >= 100) {
3181 ERROR("Error gid printing map string");
3182 return -1;
3183 }
3184
3185 /* "g:pathgid:rootgid+pathgid:1" */
3186 ret = snprintf(map4, 100, "g:%d:%d:1", (gid_t)sb.st_gid,
3187 rootgid + (gid_t)sb.st_gid);
3188 if (ret < 0 || ret >= 100) {
3189 ERROR("Error gid printing map string");
3190 return -1;
3191 }
3192
3193 /* "g:hostgid:hostgid:1" */
3194 ret = snprintf(map5, 100, "g:%d:%d:1", hostgid, hostgid);
3195 if (ret < 0 || ret >= 100) {
3196 ERROR("Error gid printing map string");
3197 return -1;
3198 }
3199
3200 /* "0:pathgid" (chown) */
3201 ret = snprintf(ugid, 100, "0:%d", (gid_t)sb.st_gid);
3202 if (ret < 0 || ret >= 100) {
3203 ERROR("Error owner printing format string for chown");
3204 return -1;
3205 }
3206
3207 if (hostgid == sb.st_gid)
3208 ret = run_command(cmd_output, sizeof(cmd_output),
3209 chown_mapped_root_exec_wrapper,
3210 (void *)args1);
3211 else
3212 ret = run_command(cmd_output, sizeof(cmd_output),
3213 chown_mapped_root_exec_wrapper,
3214 (void *)args2);
3215 if (ret < 0)
3216 ERROR("lxc-usernsexec failed: %s", cmd_output);
3217
3218 return ret;
3219 }
3220
3221 /* NOTE: Must not be called from inside the container namespace! */
3222 int lxc_create_tmp_proc_mount(struct lxc_conf *conf)
3223 {
3224 int mounted;
3225
3226 mounted = lxc_mount_proc_if_needed(conf->rootfs.path ? conf->rootfs.mount : "");
3227 if (mounted == -1) {
3228 SYSERROR("Failed to mount proc in the container");
3229 /* continue only if there is no rootfs */
3230 if (conf->rootfs.path)
3231 return -1;
3232 } else if (mounted == 1) {
3233 conf->tmp_umount_proc = true;
3234 }
3235
3236 return 0;
3237 }
3238
3239 void tmp_proc_unmount(struct lxc_conf *lxc_conf)
3240 {
3241 if (!lxc_conf->tmp_umount_proc)
3242 return;
3243
3244 (void)umount2("/proc", MNT_DETACH);
3245 lxc_conf->tmp_umount_proc = false;
3246 }
3247
3248 /* Walk /proc/mounts and change any shared entries to slave. */
3249 void remount_all_slave(void)
3250 {
3251 __do_free char *line = NULL;
3252 __do_fclose FILE *f = NULL;
3253 __do_close_prot_errno int memfd = -EBADF, mntinfo_fd = -EBADF;
3254 int ret;
3255 ssize_t copied;
3256 size_t len = 0;
3257
3258 mntinfo_fd = open("/proc/self/mountinfo", O_RDONLY | O_CLOEXEC);
3259 if (mntinfo_fd < 0) {
3260 SYSERROR("Failed to open \"/proc/self/mountinfo\"");
3261 return;
3262 }
3263
3264 memfd = memfd_create(".lxc_mountinfo", MFD_CLOEXEC);
3265 if (memfd < 0) {
3266 char template[] = P_tmpdir "/.lxc_mountinfo_XXXXXX";
3267
3268 if (errno != ENOSYS) {
3269 SYSERROR("Failed to create temporary in-memory file");
3270 return;
3271 }
3272
3273 memfd = lxc_make_tmpfile(template, true);
3274 if (memfd < 0) {
3275 WARN("Failed to create temporary file");
3276 return;
3277 }
3278 }
3279
3280 again:
3281 copied = lxc_sendfile_nointr(memfd, mntinfo_fd, NULL, LXC_SENDFILE_MAX);
3282 if (copied < 0) {
3283 if (errno == EINTR)
3284 goto again;
3285
3286 SYSERROR("Failed to copy \"/proc/self/mountinfo\"");
3287 return;
3288 }
3289
3290 ret = lseek(memfd, 0, SEEK_SET);
3291 if (ret < 0) {
3292 SYSERROR("Failed to reset file descriptor offset");
3293 return;
3294 }
3295
3296 f = fdopen(memfd, "r");
3297 if (!f) {
3298 SYSERROR("Failed to open copy of \"/proc/self/mountinfo\" to mark all shared. Continuing");
3299 return;
3300 }
3301
3302 /*
3303 * After a successful fdopen() memfd will be closed when calling
3304 * fclose(f). Calling close(memfd) afterwards is undefined.
3305 */
3306 move_fd(memfd);
3307
3308 while (getline(&line, &len, f) != -1) {
3309 char *opts, *target;
3310
3311 target = get_field(line, 4);
3312 if (!target)
3313 continue;
3314
3315 opts = get_field(target, 2);
3316 if (!opts)
3317 continue;
3318
3319 null_endofword(opts);
3320 if (!strstr(opts, "shared"))
3321 continue;
3322
3323 null_endofword(target);
3324 ret = mount(NULL, target, NULL, MS_SLAVE, NULL);
3325 if (ret < 0) {
3326 SYSERROR("Failed to make \"%s\" MS_SLAVE", target);
3327 ERROR("Continuing...");
3328 continue;
3329 }
3330 TRACE("Remounted \"%s\" as MS_SLAVE", target);
3331 }
3332 TRACE("Remounted all mount table entries as MS_SLAVE");
3333 }
3334
3335 static int lxc_execute_bind_init(struct lxc_handler *handler)
3336 {
3337 int ret;
3338 char *p;
3339 char path[PATH_MAX], destpath[PATH_MAX];
3340 struct lxc_conf *conf = handler->conf;
3341
3342 /* If init exists in the container, don't bind mount a static one */
3343 p = choose_init(conf->rootfs.mount);
3344 if (p) {
3345 __do_free char *old = p;
3346
3347 p = strdup(old + strlen(conf->rootfs.mount));
3348 if (!p)
3349 return -ENOMEM;
3350
3351 INFO("Found existing init at \"%s\"", p);
3352 goto out;
3353 }
3354
3355 ret = snprintf(path, PATH_MAX, SBINDIR "/init.lxc.static");
3356 if (ret < 0 || ret >= PATH_MAX)
3357 return -1;
3358
3359 if (!file_exists(path)) {
3360 ERROR("The file \"%s\" does not exist on host", path);
3361 return -1;
3362 }
3363
3364 ret = snprintf(destpath, PATH_MAX, "%s" P_tmpdir "%s", conf->rootfs.mount, "/.lxc-init");
3365 if (ret < 0 || ret >= PATH_MAX)
3366 return -1;
3367
3368 if (!file_exists(destpath)) {
3369 ret = mknod(destpath, S_IFREG | 0000, 0);
3370 if (ret < 0 && errno != EEXIST) {
3371 SYSERROR("Failed to create dummy \"%s\" file as bind mount target", destpath);
3372 return -1;
3373 }
3374 }
3375
3376 ret = safe_mount(path, destpath, "none", MS_BIND, NULL, conf->rootfs.mount);
3377 if (ret < 0) {
3378 SYSERROR("Failed to bind mount lxc.init.static into container");
3379 return -1;
3380 }
3381
3382 p = strdup(destpath + strlen(conf->rootfs.mount));
3383 if (!p)
3384 return -ENOMEM;
3385
3386 INFO("Bind mounted lxc.init.static into container at \"%s\"", path);
3387 out:
3388 ((struct execute_args *)handler->data)->init_fd = -1;
3389 ((struct execute_args *)handler->data)->init_path = p;
3390 return 0;
3391 }
3392
3393 /* This does the work of remounting / if it is shared, calling the container
3394 * pre-mount hooks, and mounting the rootfs.
3395 */
3396 int lxc_setup_rootfs_prepare_root(struct lxc_conf *conf, const char *name,
3397 const char *lxcpath)
3398 {
3399 int ret;
3400
3401 if (conf->rootfs_setup) {
3402 const char *path = conf->rootfs.mount;
3403
3404 /* The rootfs was set up in another namespace. bind-mount it to
3405 * give us a mount in our own ns so we can pivot_root to it
3406 */
3407 ret = mount(path, path, "rootfs", MS_BIND, NULL);
3408 if (ret < 0) {
3409 ERROR("Failed to bind mount container / onto itself");
3410 return -1;
3411 }
3412
3413 TRACE("Bind mounted container / onto itself");
3414 return 0;
3415 }
3416
3417 remount_all_slave();
3418
3419 ret = run_lxc_hooks(name, "pre-mount", conf, NULL);
3420 if (ret < 0) {
3421 ERROR("Failed to run pre-mount hooks");
3422 return -1;
3423 }
3424
3425 ret = lxc_mount_rootfs(conf);
3426 if (ret < 0) {
3427 ERROR("Failed to setup rootfs for");
3428 return -1;
3429 }
3430
3431 conf->rootfs_setup = true;
3432 return 0;
3433 }
3434
3435 static bool verify_start_hooks(struct lxc_conf *conf)
3436 {
3437 char path[PATH_MAX];
3438 struct lxc_list *it;
3439
3440 lxc_list_for_each (it, &conf->hooks[LXCHOOK_START]) {
3441 int ret;
3442 char *hookname = it->elem;
3443
3444 ret = snprintf(path, PATH_MAX, "%s%s",
3445 conf->rootfs.path ? conf->rootfs.mount : "",
3446 hookname);
3447 if (ret < 0 || ret >= PATH_MAX)
3448 return false;
3449
3450 ret = access(path, X_OK);
3451 if (ret < 0) {
3452 SYSERROR("Start hook \"%s\" not found in container",
3453 hookname);
3454 return false;
3455 }
3456
3457 return true;
3458 }
3459
3460 return true;
3461 }
3462
3463 static bool execveat_supported(void)
3464 {
3465 lxc_raw_execveat(-1, "", NULL, NULL, AT_EMPTY_PATH);
3466 if (errno == ENOSYS)
3467 return false;
3468
3469 return true;
3470 }
3471
3472 int lxc_setup(struct lxc_handler *handler)
3473 {
3474 int ret;
3475 const char *lxcpath = handler->lxcpath, *name = handler->name;
3476 struct lxc_conf *lxc_conf = handler->conf;
3477
3478 ret = lxc_setup_rootfs_prepare_root(lxc_conf, name, lxcpath);
3479 if (ret < 0) {
3480 ERROR("Failed to setup rootfs");
3481 return -1;
3482 }
3483
3484 if (handler->nsfd[LXC_NS_UTS] == -1) {
3485 ret = setup_utsname(lxc_conf->utsname);
3486 if (ret < 0) {
3487 ERROR("Failed to setup the utsname %s", name);
3488 return -1;
3489 }
3490 }
3491
3492 ret = lxc_setup_keyring();
3493 if (ret < 0)
3494 return -1;
3495
3496 ret = lxc_setup_network_in_child_namespaces(lxc_conf, &lxc_conf->network);
3497 if (ret < 0) {
3498 ERROR("Failed to setup network");
3499 return -1;
3500 }
3501
3502 ret = lxc_network_send_name_and_ifindex_to_parent(handler);
3503 if (ret < 0) {
3504 ERROR("Failed to send network device names and ifindices to parent");
3505 return -1;
3506 }
3507
3508 if (lxc_conf->autodev > 0) {
3509 ret = mount_autodev(name, &lxc_conf->rootfs, lxcpath);
3510 if (ret < 0) {
3511 ERROR("Failed to mount \"/dev\"");
3512 return -1;
3513 }
3514 }
3515
3516 /* Do automatic mounts (mainly /proc and /sys), but exclude those that
3517 * need to wait until other stuff has finished.
3518 */
3519 ret = lxc_mount_auto_mounts(lxc_conf, lxc_conf->auto_mounts & ~LXC_AUTO_CGROUP_MASK, handler);
3520 if (ret < 0) {
3521 ERROR("Failed to setup first automatic mounts");
3522 return -1;
3523 }
3524
3525 ret = setup_mount(lxc_conf, &lxc_conf->rootfs, lxc_conf->fstab, name, lxcpath);
3526 if (ret < 0) {
3527 ERROR("Failed to setup mounts");
3528 return -1;
3529 }
3530
3531 if (lxc_conf->is_execute) {
3532 if (execveat_supported()) {
3533 int fd;
3534 char path[PATH_MAX];
3535
3536 ret = snprintf(path, PATH_MAX, SBINDIR "/init.lxc.static");
3537 if (ret < 0 || ret >= PATH_MAX) {
3538 ERROR("Path to init.lxc.static too long");
3539 return -1;
3540 }
3541
3542 fd = open(path, O_PATH | O_CLOEXEC);
3543 if (fd < 0) {
3544 SYSERROR("Unable to open lxc.init.static");
3545 return -1;
3546 }
3547
3548 ((struct execute_args *)handler->data)->init_fd = fd;
3549 ((struct execute_args *)handler->data)->init_path = NULL;
3550 } else {
3551 ret = lxc_execute_bind_init(handler);
3552 if (ret < 0) {
3553 ERROR("Failed to bind-mount the lxc init system");
3554 return -1;
3555 }
3556 }
3557 }
3558
3559 /* Now mount only cgroups, if wanted. Before, /sys could not have been
3560 * mounted. It is guaranteed to be mounted now either through
3561 * automatically or via fstab entries.
3562 */
3563 ret = lxc_mount_auto_mounts(lxc_conf, lxc_conf->auto_mounts & LXC_AUTO_CGROUP_MASK, handler);
3564 if (ret < 0) {
3565 ERROR("Failed to setup remaining automatic mounts");
3566 return -1;
3567 }
3568
3569 ret = run_lxc_hooks(name, "mount", lxc_conf, NULL);
3570 if (ret < 0) {
3571 ERROR("Failed to run mount hooks");
3572 return -1;
3573 }
3574
3575 if (lxc_conf->autodev > 0) {
3576 ret = run_lxc_hooks(name, "autodev", lxc_conf, NULL);
3577 if (ret < 0) {
3578 ERROR("Failed to run autodev hooks");
3579 return -1;
3580 }
3581
3582 ret = lxc_fill_autodev(&lxc_conf->rootfs);
3583 if (ret < 0) {
3584 ERROR("Failed to populate \"/dev\"");
3585 return -1;
3586 }
3587 }
3588
3589 if (!lxc_list_empty(&lxc_conf->mount_list)) {
3590 ret = setup_mount_entries(lxc_conf, &lxc_conf->rootfs,
3591 &lxc_conf->mount_list, name, lxcpath);
3592 if (ret < 0) {
3593 ERROR("Failed to setup mount entries");
3594 return -1;
3595 }
3596 }
3597
3598 /* Make sure any start hooks are in the container */
3599 if (!verify_start_hooks(lxc_conf)) {
3600 ERROR("Failed to verify start hooks");
3601 return -1;
3602 }
3603
3604 ret = lxc_setup_console(&lxc_conf->rootfs, &lxc_conf->console,
3605 lxc_conf->ttys.dir);
3606 if (ret < 0) {
3607 ERROR("Failed to setup console");
3608 return -1;
3609 }
3610
3611 ret = lxc_setup_dev_symlinks(&lxc_conf->rootfs);
3612 if (ret < 0) {
3613 ERROR("Failed to setup \"/dev\" symlinks");
3614 return -1;
3615 }
3616
3617 ret = lxc_create_tmp_proc_mount(lxc_conf);
3618 if (ret < 0) {
3619 ERROR("Failed to \"/proc\" LSMs");
3620 return -1;
3621 }
3622
3623 ret = lxc_setup_rootfs_switch_root(&lxc_conf->rootfs);
3624 if (ret < 0) {
3625 ERROR("Failed to pivot root into rootfs");
3626 return -1;
3627 }
3628
3629 ret = lxc_setup_devpts(lxc_conf);
3630 if (ret < 0) {
3631 ERROR("Failed to setup new devpts instance");
3632 return -1;
3633 }
3634
3635 ret = lxc_create_ttys(handler);
3636 if (ret < 0)
3637 return -1;
3638
3639 ret = setup_personality(lxc_conf->personality);
3640 if (ret < 0) {
3641 ERROR("Failed to set personality");
3642 return -1;
3643 }
3644
3645 /* Set sysctl value to a path under /proc/sys as determined from the
3646 * key. For e.g. net.ipv4.ip_forward translated to
3647 * /proc/sys/net/ipv4/ip_forward.
3648 */
3649 if (!lxc_list_empty(&lxc_conf->sysctls)) {
3650 ret = setup_sysctl_parameters(&lxc_conf->sysctls);
3651 if (ret < 0) {
3652 ERROR("Failed to setup sysctl parameters");
3653 return -1;
3654 }
3655 }
3656
3657 if (!lxc_list_empty(&lxc_conf->keepcaps)) {
3658 if (!lxc_list_empty(&lxc_conf->caps)) {
3659 ERROR("Container requests lxc.cap.drop and "
3660 "lxc.cap.keep: either use lxc.cap.drop or "
3661 "lxc.cap.keep, not both");
3662 return -1;
3663 }
3664
3665 if (dropcaps_except(&lxc_conf->keepcaps)) {
3666 ERROR("Failed to keep capabilities");
3667 return -1;
3668 }
3669 } else if (setup_caps(&lxc_conf->caps)) {
3670 ERROR("Failed to drop capabilities");
3671 return -1;
3672 }
3673
3674 NOTICE("The container \"%s\" is set up", name);
3675
3676 return 0;
3677 }
3678
3679 int run_lxc_hooks(const char *name, char *hookname, struct lxc_conf *conf,
3680 char *argv[])
3681 {
3682 struct lxc_list *it;
3683 int which = -1;
3684
3685 if (strcmp(hookname, "pre-start") == 0)
3686 which = LXCHOOK_PRESTART;
3687 else if (strcmp(hookname, "start-host") == 0)
3688 which = LXCHOOK_START_HOST;
3689 else if (strcmp(hookname, "pre-mount") == 0)
3690 which = LXCHOOK_PREMOUNT;
3691 else if (strcmp(hookname, "mount") == 0)
3692 which = LXCHOOK_MOUNT;
3693 else if (strcmp(hookname, "autodev") == 0)
3694 which = LXCHOOK_AUTODEV;
3695 else if (strcmp(hookname, "start") == 0)
3696 which = LXCHOOK_START;
3697 else if (strcmp(hookname, "stop") == 0)
3698 which = LXCHOOK_STOP;
3699 else if (strcmp(hookname, "post-stop") == 0)
3700 which = LXCHOOK_POSTSTOP;
3701 else if (strcmp(hookname, "clone") == 0)
3702 which = LXCHOOK_CLONE;
3703 else if (strcmp(hookname, "destroy") == 0)
3704 which = LXCHOOK_DESTROY;
3705 else
3706 return -1;
3707
3708 lxc_list_for_each (it, &conf->hooks[which]) {
3709 int ret;
3710 char *hook = it->elem;
3711
3712 ret = run_script_argv(name, conf->hooks_version, "lxc", hook,
3713 hookname, argv);
3714 if (ret < 0)
3715 return -1;
3716 }
3717
3718 return 0;
3719 }
3720
3721 int lxc_clear_config_caps(struct lxc_conf *c)
3722 {
3723 struct lxc_list *it, *next;
3724
3725 lxc_list_for_each_safe (it, &c->caps, next) {
3726 lxc_list_del(it);
3727 free(it->elem);
3728 free(it);
3729 }
3730
3731 return 0;
3732 }
3733
3734 static int lxc_free_idmap(struct lxc_list *id_map)
3735 {
3736 struct lxc_list *it, *next;
3737
3738 lxc_list_for_each_safe (it, id_map, next) {
3739 lxc_list_del(it);
3740 free(it->elem);
3741 free(it);
3742 }
3743
3744 return 0;
3745 }
3746
3747 int lxc_clear_idmaps(struct lxc_conf *c)
3748 {
3749 return lxc_free_idmap(&c->id_map);
3750 }
3751
3752 int lxc_clear_config_keepcaps(struct lxc_conf *c)
3753 {
3754 struct lxc_list *it, *next;
3755
3756 lxc_list_for_each_safe (it, &c->keepcaps, next) {
3757 lxc_list_del(it);
3758 free(it->elem);
3759 free(it);
3760 }
3761
3762 return 0;
3763 }
3764
3765 int lxc_clear_namespace(struct lxc_conf *c)
3766 {
3767 int i;
3768 for (i = 0; i < LXC_NS_MAX; i++) {
3769 free(c->ns_share[i]);
3770 c->ns_share[i] = NULL;
3771 }
3772 return 0;
3773 }
3774
3775 int lxc_clear_cgroups(struct lxc_conf *c, const char *key, int version)
3776 {
3777 char *global_token, *namespaced_token;
3778 size_t namespaced_token_len;
3779 struct lxc_list *it, *next, *list;
3780 const char *k = key;
3781 bool all = false;
3782
3783 if (version == CGROUP2_SUPER_MAGIC) {
3784 global_token = "lxc.cgroup2";
3785 namespaced_token = "lxc.cgroup2.";
3786 namespaced_token_len = STRLITERALLEN("lxc.cgroup2.");
3787 list = &c->cgroup2;
3788 } else if (version == CGROUP_SUPER_MAGIC) {
3789 global_token = "lxc.cgroup";
3790 namespaced_token = "lxc.cgroup.";
3791 namespaced_token_len = STRLITERALLEN("lxc.cgroup.");
3792 list = &c->cgroup;
3793 } else {
3794 return -EINVAL;
3795 }
3796
3797 if (strcmp(key, global_token) == 0)
3798 all = true;
3799 else if (strncmp(key, namespaced_token, namespaced_token_len) == 0)
3800 k += namespaced_token_len;
3801 else
3802 return -EINVAL;
3803
3804 lxc_list_for_each_safe (it, list, next) {
3805 struct lxc_cgroup *cg = it->elem;
3806
3807 if (!all && strcmp(cg->subsystem, k) != 0)
3808 continue;
3809
3810 lxc_list_del(it);
3811 free(cg->subsystem);
3812 free(cg->value);
3813 free(cg);
3814 free(it);
3815 }
3816
3817 return 0;
3818 }
3819
3820 int lxc_clear_limits(struct lxc_conf *c, const char *key)
3821 {
3822 struct lxc_list *it, *next;
3823 const char *k = NULL;
3824 bool all = false;
3825
3826 if (strcmp(key, "lxc.limit") == 0 || strcmp(key, "lxc.prlimit") == 0)
3827 all = true;
3828 else if (strncmp(key, "lxc.limit.", STRLITERALLEN("lxc.limit.")) == 0)
3829 k = key + STRLITERALLEN("lxc.limit.");
3830 else if (strncmp(key, "lxc.prlimit.", STRLITERALLEN("lxc.prlimit.")) == 0)
3831 k = key + STRLITERALLEN("lxc.prlimit.");
3832 else
3833 return -1;
3834
3835 lxc_list_for_each_safe (it, &c->limits, next) {
3836 struct lxc_limit *lim = it->elem;
3837
3838 if (!all && strcmp(lim->resource, k) != 0)
3839 continue;
3840
3841 lxc_list_del(it);
3842 free(lim->resource);
3843 free(lim);
3844 free(it);
3845 }
3846
3847 return 0;
3848 }
3849
3850 int lxc_clear_sysctls(struct lxc_conf *c, const char *key)
3851 {
3852 struct lxc_list *it, *next;
3853 const char *k = NULL;
3854 bool all = false;
3855
3856 if (strcmp(key, "lxc.sysctl") == 0)
3857 all = true;
3858 else if (strncmp(key, "lxc.sysctl.", STRLITERALLEN("lxc.sysctl.")) == 0)
3859 k = key + STRLITERALLEN("lxc.sysctl.");
3860 else
3861 return -1;
3862
3863 lxc_list_for_each_safe (it, &c->sysctls, next) {
3864 struct lxc_sysctl *elem = it->elem;
3865
3866 if (!all && strcmp(elem->key, k) != 0)
3867 continue;
3868
3869 lxc_list_del(it);
3870 free(elem->key);
3871 free(elem->value);
3872 free(elem);
3873 free(it);
3874 }
3875
3876 return 0;
3877 }
3878
3879 int lxc_clear_procs(struct lxc_conf *c, const char *key)
3880 {
3881 struct lxc_list *it, *next;
3882 const char *k = NULL;
3883 bool all = false;
3884
3885 if (strcmp(key, "lxc.proc") == 0)
3886 all = true;
3887 else if (strncmp(key, "lxc.proc.", STRLITERALLEN("lxc.proc.")) == 0)
3888 k = key + STRLITERALLEN("lxc.proc.");
3889 else
3890 return -1;
3891
3892 lxc_list_for_each_safe (it, &c->procs, next) {
3893 struct lxc_proc *proc = it->elem;
3894
3895 if (!all && strcmp(proc->filename, k) != 0)
3896 continue;
3897
3898 lxc_list_del(it);
3899 free(proc->filename);
3900 free(proc->value);
3901 free(proc);
3902 free(it);
3903 }
3904
3905 return 0;
3906 }
3907
3908 int lxc_clear_groups(struct lxc_conf *c)
3909 {
3910 struct lxc_list *it, *next;
3911
3912 lxc_list_for_each_safe (it, &c->groups, next) {
3913 lxc_list_del(it);
3914 free(it->elem);
3915 free(it);
3916 }
3917
3918 return 0;
3919 }
3920
3921 int lxc_clear_environment(struct lxc_conf *c)
3922 {
3923 struct lxc_list *it, *next;
3924
3925 lxc_list_for_each_safe (it, &c->environment, next) {
3926 lxc_list_del(it);
3927 free(it->elem);
3928 free(it);
3929 }
3930
3931 return 0;
3932 }
3933
3934 int lxc_clear_mount_entries(struct lxc_conf *c)
3935 {
3936 struct lxc_list *it, *next;
3937
3938 lxc_list_for_each_safe (it, &c->mount_list, next) {
3939 lxc_list_del(it);
3940 free(it->elem);
3941 free(it);
3942 }
3943
3944 return 0;
3945 }
3946
3947 int lxc_clear_automounts(struct lxc_conf *c)
3948 {
3949 c->auto_mounts = 0;
3950 return 0;
3951 }
3952
3953 int lxc_clear_hooks(struct lxc_conf *c, const char *key)
3954 {
3955 int i;
3956 struct lxc_list *it, *next;
3957 const char *k = NULL;
3958 bool all = false, done = false;
3959
3960 if (strcmp(key, "lxc.hook") == 0)
3961 all = true;
3962 else if (strncmp(key, "lxc.hook.", STRLITERALLEN("lxc.hook.")) == 0)
3963 k = key + STRLITERALLEN("lxc.hook.");
3964 else
3965 return -1;
3966
3967 for (i = 0; i < NUM_LXC_HOOKS; i++) {
3968 if (all || strcmp(k, lxchook_names[i]) == 0) {
3969 lxc_list_for_each_safe (it, &c->hooks[i], next) {
3970 lxc_list_del(it);
3971 free(it->elem);
3972 free(it);
3973 }
3974
3975 done = true;
3976 }
3977 }
3978
3979 if (!done) {
3980 ERROR("Invalid hook key: %s", key);
3981 return -1;
3982 }
3983
3984 return 0;
3985 }
3986
3987 static inline void lxc_clear_aliens(struct lxc_conf *conf)
3988 {
3989 struct lxc_list *it, *next;
3990
3991 lxc_list_for_each_safe (it, &conf->aliens, next) {
3992 lxc_list_del(it);
3993 free(it->elem);
3994 free(it);
3995 }
3996 }
3997
3998 void lxc_clear_includes(struct lxc_conf *conf)
3999 {
4000 struct lxc_list *it, *next;
4001
4002 lxc_list_for_each_safe (it, &conf->includes, next) {
4003 lxc_list_del(it);
4004 free(it->elem);
4005 free(it);
4006 }
4007 }
4008
4009 int lxc_clear_apparmor_raw(struct lxc_conf *c)
4010 {
4011 struct lxc_list *it, *next;
4012
4013 lxc_list_for_each_safe (it, &c->lsm_aa_raw, next) {
4014 lxc_list_del(it);
4015 free(it->elem);
4016 free(it);
4017 }
4018
4019 return 0;
4020 }
4021
4022 void lxc_conf_free(struct lxc_conf *conf)
4023 {
4024 if (!conf)
4025 return;
4026
4027 if (current_config == conf)
4028 current_config = NULL;
4029 lxc_terminal_conf_free(&conf->console);
4030 free(conf->rootfs.mount);
4031 free(conf->rootfs.bdev_type);
4032 free(conf->rootfs.options);
4033 free(conf->rootfs.path);
4034 free(conf->logfile);
4035 if (conf->logfd != -1)
4036 close(conf->logfd);
4037 free(conf->utsname);
4038 free(conf->ttys.dir);
4039 free(conf->ttys.tty_names);
4040 free(conf->fstab);
4041 free(conf->rcfile);
4042 free(conf->execute_cmd);
4043 free(conf->init_cmd);
4044 free(conf->init_cwd);
4045 free(conf->unexpanded_config);
4046 free(conf->syslog);
4047 lxc_free_networks(&conf->network);
4048 free(conf->lsm_aa_profile);
4049 free(conf->lsm_aa_profile_computed);
4050 free(conf->lsm_se_context);
4051 lxc_seccomp_free(conf);
4052 lxc_clear_config_caps(conf);
4053 lxc_clear_config_keepcaps(conf);
4054 lxc_clear_cgroups(conf, "lxc.cgroup", CGROUP_SUPER_MAGIC);
4055 lxc_clear_cgroups(conf, "lxc.cgroup2", CGROUP2_SUPER_MAGIC);
4056 lxc_clear_hooks(conf, "lxc.hook");
4057 lxc_clear_mount_entries(conf);
4058 lxc_clear_idmaps(conf);
4059 lxc_clear_groups(conf);
4060 lxc_clear_includes(conf);
4061 lxc_clear_aliens(conf);
4062 lxc_clear_environment(conf);
4063 lxc_clear_limits(conf, "lxc.prlimit");
4064 lxc_clear_sysctls(conf, "lxc.sysctl");
4065 lxc_clear_procs(conf, "lxc.proc");
4066 lxc_clear_apparmor_raw(conf);
4067 lxc_clear_namespace(conf);
4068 free(conf->cgroup_meta.dir);
4069 free(conf->cgroup_meta.controllers);
4070 free(conf->shmount.path_host);
4071 free(conf->shmount.path_cont);
4072 free(conf);
4073 }
4074
4075 struct userns_fn_data {
4076 int (*fn)(void *);
4077 const char *fn_name;
4078 void *arg;
4079 int p[2];
4080 };
4081
4082 static int run_userns_fn(void *data)
4083 {
4084 int ret;
4085 char c;
4086 struct userns_fn_data *d = data;
4087
4088 /* Close write end of the pipe. */
4089 close(d->p[1]);
4090
4091 /* Wait for parent to finish establishing a new mapping in the user
4092 * namespace we are executing in.
4093 */
4094 ret = lxc_read_nointr(d->p[0], &c, 1);
4095 /* Close read end of the pipe. */
4096 close(d->p[0]);
4097 if (ret != 1)
4098 return -1;
4099
4100 if (d->fn_name)
4101 TRACE("Calling function \"%s\"", d->fn_name);
4102
4103 /* Call function to run. */
4104 return d->fn(d->arg);
4105 }
4106
4107 static struct id_map *mapped_nsid_add(struct lxc_conf *conf, unsigned id,
4108 enum idtype idtype)
4109 {
4110 const struct id_map *map;
4111 struct id_map *retmap;
4112
4113 map = find_mapped_nsid_entry(conf, id, idtype);
4114 if (!map)
4115 return NULL;
4116
4117 retmap = malloc(sizeof(*retmap));
4118 if (!retmap)
4119 return NULL;
4120
4121 memcpy(retmap, map, sizeof(*retmap));
4122 return retmap;
4123 }
4124
4125 static struct id_map *find_mapped_hostid_entry(struct lxc_conf *conf,
4126 unsigned id, enum idtype idtype)
4127 {
4128 struct id_map *map;
4129 struct lxc_list *it;
4130 struct id_map *retmap = NULL;
4131
4132 lxc_list_for_each (it, &conf->id_map) {
4133 map = it->elem;
4134 if (map->idtype != idtype)
4135 continue;
4136
4137 if (id >= map->hostid && id < map->hostid + map->range) {
4138 retmap = map;
4139 break;
4140 }
4141 }
4142
4143 return retmap;
4144 }
4145
4146 /* Allocate a new {g,u}id mapping for the given {g,u}id. Re-use an already
4147 * existing one or establish a new one.
4148 */
4149 static struct id_map *mapped_hostid_add(struct lxc_conf *conf, uid_t id,
4150 enum idtype type)
4151 {
4152 int hostid_mapped;
4153 struct id_map *entry = NULL, *tmp = NULL;
4154
4155 entry = malloc(sizeof(*entry));
4156 if (!entry)
4157 return NULL;
4158
4159 /* Reuse existing mapping. */
4160 tmp = find_mapped_hostid_entry(conf, id, type);
4161 if (tmp)
4162 return memcpy(entry, tmp, sizeof(*entry));
4163
4164 /* Find new mapping. */
4165 hostid_mapped = find_unmapped_nsid(conf, type);
4166 if (hostid_mapped < 0) {
4167 DEBUG("Failed to find free mapping for id %d", id);
4168 free(entry);
4169 return NULL;
4170 }
4171
4172 entry->idtype = type;
4173 entry->nsid = hostid_mapped;
4174 entry->hostid = (unsigned long)id;
4175 entry->range = 1;
4176
4177 return entry;
4178 }
4179
4180 struct lxc_list *get_minimal_idmap(struct lxc_conf *conf)
4181 {
4182 __do_free struct id_map *container_root_uid = NULL,
4183 *container_root_gid = NULL,
4184 *host_uid_map = NULL, *host_gid_map = NULL;
4185 __do_free struct lxc_list *idmap = NULL;
4186 uid_t euid, egid;
4187 uid_t nsuid = (conf->root_nsuid_map != NULL) ? 0 : conf->init_uid;
4188 gid_t nsgid = (conf->root_nsgid_map != NULL) ? 0 : conf->init_gid;
4189 struct lxc_list *tmplist = NULL;
4190
4191 /* Find container root mappings. */
4192 container_root_uid = mapped_nsid_add(conf, nsuid, ID_TYPE_UID);
4193 if (!container_root_uid) {
4194 DEBUG("Failed to find mapping for namespace uid %d", 0);
4195 return NULL;
4196 }
4197 euid = geteuid();
4198 if (euid >= container_root_uid->hostid &&
4199 euid < (container_root_uid->hostid + container_root_uid->range))
4200 host_uid_map = container_root_uid;
4201
4202 container_root_gid = mapped_nsid_add(conf, nsgid, ID_TYPE_GID);
4203 if (!container_root_gid) {
4204 DEBUG("Failed to find mapping for namespace gid %d", 0);
4205 return NULL;
4206 }
4207 egid = getegid();
4208 if (egid >= container_root_gid->hostid &&
4209 egid < (container_root_gid->hostid + container_root_gid->range))
4210 host_gid_map = container_root_gid;
4211
4212 /* Check whether the {g,u}id of the user has a mapping. */
4213 if (!host_uid_map)
4214 host_uid_map = mapped_hostid_add(conf, euid, ID_TYPE_UID);
4215 if (!host_uid_map) {
4216 DEBUG("Failed to find mapping for uid %d", euid);
4217 return NULL;
4218 }
4219
4220 if (!host_gid_map)
4221 host_gid_map = mapped_hostid_add(conf, egid, ID_TYPE_GID);
4222 if (!host_gid_map) {
4223 DEBUG("Failed to find mapping for gid %d", egid);
4224 return NULL;
4225 }
4226
4227 /* Allocate new {g,u}id map list. */
4228 idmap = malloc(sizeof(*idmap));
4229 if (!idmap)
4230 return NULL;
4231 lxc_list_init(idmap);
4232
4233 /* Add container root to the map. */
4234 tmplist = malloc(sizeof(*tmplist));
4235 if (!tmplist)
4236 return NULL;
4237 lxc_list_add_elem(tmplist, container_root_uid);
4238 lxc_list_add_tail(idmap, tmplist);
4239
4240 if (host_uid_map && (host_uid_map != container_root_uid)) {
4241 /* idmap will now keep track of that memory. */
4242 move_ptr(container_root_uid);
4243
4244 /* Add container root to the map. */
4245 tmplist = malloc(sizeof(*tmplist));
4246 if (!tmplist)
4247 return NULL;
4248 lxc_list_add_elem(tmplist, host_uid_map);
4249 lxc_list_add_tail(idmap, tmplist);
4250 }
4251 /* idmap will now keep track of that memory. */
4252 move_ptr(container_root_uid);
4253 /* idmap will now keep track of that memory. */
4254 move_ptr(host_uid_map);
4255
4256 tmplist = malloc(sizeof(*tmplist));
4257 if (!tmplist)
4258 return NULL;
4259 lxc_list_add_elem(tmplist, container_root_gid);
4260 lxc_list_add_tail(idmap, tmplist);
4261
4262 if (host_gid_map && (host_gid_map != container_root_gid)) {
4263 /* idmap will now keep track of that memory. */
4264 move_ptr(container_root_gid);
4265
4266 tmplist = malloc(sizeof(*tmplist));
4267 if (!tmplist)
4268 return NULL;
4269 lxc_list_add_elem(tmplist, host_gid_map);
4270 lxc_list_add_tail(idmap, tmplist);
4271 }
4272 /* idmap will now keep track of that memory. */
4273 move_ptr(container_root_gid);
4274 /* idmap will now keep track of that memory. */
4275 move_ptr(host_gid_map);
4276
4277 TRACE("Allocated minimal idmapping");
4278 return move_ptr(idmap);
4279 }
4280
4281 /* Run a function in a new user namespace.
4282 * The caller's euid/egid will be mapped if it is not already.
4283 * Afaict, userns_exec_1() is only used to operate based on privileges for the
4284 * user's own {g,u}id on the host and for the container root's unmapped {g,u}id.
4285 * This means we require only to establish a mapping from:
4286 * - the container root {g,u}id as seen from the host > user's host {g,u}id
4287 * - the container root -> some sub{g,u}id
4288 * The former we add, if the user did not specify a mapping. The latter we
4289 * retrieve from the container's configured {g,u}id mappings as it must have been
4290 * there to start the container in the first place.
4291 */
4292 int userns_exec_1(struct lxc_conf *conf, int (*fn)(void *), void *data,
4293 const char *fn_name)
4294 {
4295 pid_t pid;
4296 int p[2];
4297 struct userns_fn_data d;
4298 struct lxc_list *idmap;
4299 int ret = -1, status = -1;
4300 char c = '1';
4301
4302 if (!conf)
4303 return -EINVAL;
4304
4305 idmap = get_minimal_idmap(conf);
4306 if (!idmap)
4307 return -1;
4308
4309 ret = pipe2(p, O_CLOEXEC);
4310 if (ret < 0) {
4311 SYSERROR("Failed to create pipe");
4312 return -1;
4313 }
4314 d.fn = fn;
4315 d.fn_name = fn_name;
4316 d.arg = data;
4317 d.p[0] = p[0];
4318 d.p[1] = p[1];
4319
4320 /* Clone child in new user namespace. */
4321 pid = lxc_raw_clone_cb(run_userns_fn, &d, CLONE_NEWUSER);
4322 if (pid < 0) {
4323 ERROR("Failed to clone process in new user namespace");
4324 goto on_error;
4325 }
4326
4327 close(p[0]);
4328 p[0] = -1;
4329
4330 if (lxc_log_get_level() == LXC_LOG_LEVEL_TRACE ||
4331 conf->loglevel == LXC_LOG_LEVEL_TRACE) {
4332 struct id_map *map;
4333 struct lxc_list *it;
4334
4335 lxc_list_for_each (it, idmap) {
4336 map = it->elem;
4337 TRACE("Establishing %cid mapping for \"%d\" in new "
4338 "user namespace: nsuid %lu - hostid %lu - range "
4339 "%lu",
4340 (map->idtype == ID_TYPE_UID) ? 'u' : 'g', pid,
4341 map->nsid, map->hostid, map->range);
4342 }
4343 }
4344
4345 /* Set up {g,u}id mapping for user namespace of child process. */
4346 ret = lxc_map_ids(idmap, pid);
4347 if (ret < 0) {
4348 ERROR("Error setting up {g,u}id mappings for child process \"%d\"", pid);
4349 goto on_error;
4350 }
4351
4352 /* Tell child to proceed. */
4353 if (lxc_write_nointr(p[1], &c, 1) != 1) {
4354 SYSERROR("Failed telling child process \"%d\" to proceed", pid);
4355 goto on_error;
4356 }
4357
4358 on_error:
4359 if (p[0] != -1)
4360 close(p[0]);
4361 close(p[1]);
4362
4363 /* Wait for child to finish. */
4364 if (pid > 0)
4365 status = wait_for_pid(pid);
4366
4367 if (status < 0)
4368 ret = -1;
4369
4370 return ret;
4371 }
4372
4373 int userns_exec_full(struct lxc_conf *conf, int (*fn)(void *), void *data,
4374 const char *fn_name)
4375 {
4376 pid_t pid;
4377 uid_t euid, egid;
4378 int p[2];
4379 struct id_map *map;
4380 struct lxc_list *cur;
4381 struct userns_fn_data d;
4382 int ret = -1;
4383 char c = '1';
4384 struct lxc_list *idmap = NULL, *tmplist = NULL;
4385 struct id_map *container_root_uid = NULL, *container_root_gid = NULL,
4386 *host_uid_map = NULL, *host_gid_map = NULL;
4387
4388 if (!conf)
4389 return -EINVAL;
4390
4391 ret = pipe2(p, O_CLOEXEC);
4392 if (ret < 0) {
4393 SYSERROR("opening pipe");
4394 return -1;
4395 }
4396 d.fn = fn;
4397 d.fn_name = fn_name;
4398 d.arg = data;
4399 d.p[0] = p[0];
4400 d.p[1] = p[1];
4401
4402 /* Clone child in new user namespace. */
4403 pid = lxc_clone(run_userns_fn, &d, CLONE_NEWUSER);
4404 if (pid < 0) {
4405 ERROR("Failed to clone process in new user namespace");
4406 goto on_error;
4407 }
4408
4409 close(p[0]);
4410 p[0] = -1;
4411
4412 euid = geteuid();
4413 egid = getegid();
4414
4415 /* Allocate new {g,u}id map list. */
4416 idmap = malloc(sizeof(*idmap));
4417 if (!idmap)
4418 goto on_error;
4419 lxc_list_init(idmap);
4420
4421 /* Find container root. */
4422 lxc_list_for_each (cur, &conf->id_map) {
4423 struct id_map *tmpmap;
4424
4425 tmplist = malloc(sizeof(*tmplist));
4426 if (!tmplist)
4427 goto on_error;
4428
4429 tmpmap = malloc(sizeof(*tmpmap));
4430 if (!tmpmap) {
4431 free(tmplist);
4432 goto on_error;
4433 }
4434
4435 memset(tmpmap, 0, sizeof(*tmpmap));
4436 memcpy(tmpmap, cur->elem, sizeof(*tmpmap));
4437 tmplist->elem = tmpmap;
4438
4439 lxc_list_add_tail(idmap, tmplist);
4440
4441 map = cur->elem;
4442
4443 if (map->idtype == ID_TYPE_UID)
4444 if (euid >= map->hostid && euid < map->hostid + map->range)
4445 host_uid_map = map;
4446
4447 if (map->idtype == ID_TYPE_GID)
4448 if (egid >= map->hostid && egid < map->hostid + map->range)
4449 host_gid_map = map;
4450
4451 if (map->nsid != 0)
4452 continue;
4453
4454 if (map->idtype == ID_TYPE_UID)
4455 if (container_root_uid == NULL)
4456 container_root_uid = map;
4457
4458 if (map->idtype == ID_TYPE_GID)
4459 if (container_root_gid == NULL)
4460 container_root_gid = map;
4461 }
4462
4463 if (!container_root_uid || !container_root_gid) {
4464 ERROR("No mapping for container root found");
4465 goto on_error;
4466 }
4467
4468 /* Check whether the {g,u}id of the user has a mapping. */
4469 if (!host_uid_map)
4470 host_uid_map = mapped_hostid_add(conf, euid, ID_TYPE_UID);
4471 else
4472 host_uid_map = container_root_uid;
4473
4474 if (!host_gid_map)
4475 host_gid_map = mapped_hostid_add(conf, egid, ID_TYPE_GID);
4476 else
4477 host_gid_map = container_root_gid;
4478
4479 if (!host_uid_map) {
4480 DEBUG("Failed to find mapping for uid %d", euid);
4481 goto on_error;
4482 }
4483
4484 if (!host_gid_map) {
4485 DEBUG("Failed to find mapping for gid %d", egid);
4486 goto on_error;
4487 }
4488
4489 if (host_uid_map && (host_uid_map != container_root_uid)) {
4490 /* Add container root to the map. */
4491 tmplist = malloc(sizeof(*tmplist));
4492 if (!tmplist)
4493 goto on_error;
4494 lxc_list_add_elem(tmplist, host_uid_map);
4495 lxc_list_add_tail(idmap, tmplist);
4496 }
4497 /* idmap will now keep track of that memory. */
4498 host_uid_map = NULL;
4499
4500 if (host_gid_map && (host_gid_map != container_root_gid)) {
4501 tmplist = malloc(sizeof(*tmplist));
4502 if (!tmplist)
4503 goto on_error;
4504 lxc_list_add_elem(tmplist, host_gid_map);
4505 lxc_list_add_tail(idmap, tmplist);
4506 }
4507 /* idmap will now keep track of that memory. */
4508 host_gid_map = NULL;
4509
4510 if (lxc_log_get_level() == LXC_LOG_LEVEL_TRACE ||
4511 conf->loglevel == LXC_LOG_LEVEL_TRACE) {
4512 lxc_list_for_each (cur, idmap) {
4513 map = cur->elem;
4514 TRACE("establishing %cid mapping for \"%d\" in new "
4515 "user namespace: nsuid %lu - hostid %lu - range "
4516 "%lu",
4517 (map->idtype == ID_TYPE_UID) ? 'u' : 'g', pid,
4518 map->nsid, map->hostid, map->range);
4519 }
4520 }
4521
4522 /* Set up {g,u}id mapping for user namespace of child process. */
4523 ret = lxc_map_ids(idmap, pid);
4524 if (ret < 0) {
4525 ERROR("error setting up {g,u}id mappings for child process \"%d\"", pid);
4526 goto on_error;
4527 }
4528
4529 /* Tell child to proceed. */
4530 if (lxc_write_nointr(p[1], &c, 1) != 1) {
4531 SYSERROR("Failed telling child process \"%d\" to proceed", pid);
4532 goto on_error;
4533 }
4534
4535 on_error:
4536 if (p[0] != -1)
4537 close(p[0]);
4538 close(p[1]);
4539
4540 /* Wait for child to finish. */
4541 if (pid > 0)
4542 ret = wait_for_pid(pid);
4543
4544 if (idmap) {
4545 lxc_free_idmap(idmap);
4546 free(idmap);
4547 }
4548
4549 if (host_uid_map && (host_uid_map != container_root_uid))
4550 free(host_uid_map);
4551 if (host_gid_map && (host_gid_map != container_root_gid))
4552 free(host_gid_map);
4553
4554 return ret;
4555 }
4556
4557 /* not thread-safe, do not use from api without first forking */
4558 static char *getuname(void)
4559 {
4560 __do_free char *buf = NULL;
4561 struct passwd pwent;
4562 struct passwd *pwentp = NULL;
4563 size_t bufsize;
4564 int ret;
4565
4566 bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
4567 if (bufsize == -1)
4568 bufsize = 1024;
4569
4570 buf = malloc(bufsize);
4571 if (!buf)
4572 return NULL;
4573
4574 ret = getpwuid_r(geteuid(), &pwent, buf, bufsize, &pwentp);
4575 if (!pwentp) {
4576 if (ret == 0)
4577 WARN("Could not find matched password record.");
4578
4579 ERROR("Failed to get password record - %u", geteuid());
4580 return NULL;
4581 }
4582
4583 return strdup(pwent.pw_name);
4584 }
4585
4586 /* not thread-safe, do not use from api without first forking */
4587 static char *getgname(void)
4588 {
4589 __do_free char *buf = NULL;
4590 struct group grent;
4591 struct group *grentp = NULL;
4592 size_t bufsize;
4593 int ret;
4594
4595 bufsize = sysconf(_SC_GETGR_R_SIZE_MAX);
4596 if (bufsize == -1)
4597 bufsize = 1024;
4598
4599 buf = malloc(bufsize);
4600 if (!buf)
4601 return NULL;
4602
4603 ret = getgrgid_r(getegid(), &grent, buf, bufsize, &grentp);
4604 if (!grentp) {
4605 if (ret == 0)
4606 WARN("Could not find matched group record");
4607
4608 ERROR("Failed to get group record - %u", getegid());
4609 return NULL;
4610 }
4611
4612 return strdup(grent.gr_name);
4613 }
4614
4615 /* not thread-safe, do not use from api without first forking */
4616 void suggest_default_idmap(void)
4617 {
4618 __do_free char *gname = NULL, *line = NULL, *uname = NULL;
4619 __do_fclose FILE *subuid_f = NULL, *subgid_f = NULL;
4620 unsigned int uid = 0, urange = 0, gid = 0, grange = 0;
4621 size_t len = 0;
4622
4623 uname = getuname();
4624 if (!uname)
4625 return;
4626
4627 gname = getgname();
4628 if (!gname)
4629 return;
4630
4631 subuid_f = fopen(subuidfile, "r");
4632 if (!subuid_f) {
4633 ERROR("Your system is not configured with subuids");
4634 return;
4635 }
4636
4637 while (getline(&line, &len, subuid_f) != -1) {
4638 char *p, *p2;
4639 size_t no_newline = 0;
4640
4641 p = strchr(line, ':');
4642 if (*line == '#')
4643 continue;
4644 if (!p)
4645 continue;
4646 *p = '\0';
4647 p++;
4648
4649 if (strcmp(line, uname))
4650 continue;
4651
4652 p2 = strchr(p, ':');
4653 if (!p2)
4654 continue;
4655 *p2 = '\0';
4656 p2++;
4657 if (!*p2)
4658 continue;
4659 no_newline = strcspn(p2, "\n");
4660 p2[no_newline] = '\0';
4661
4662 if (lxc_safe_uint(p, &uid) < 0)
4663 WARN("Could not parse UID");
4664 if (lxc_safe_uint(p2, &urange) < 0)
4665 WARN("Could not parse UID range");
4666 }
4667
4668 subgid_f = fopen(subgidfile, "r");
4669 if (!subgid_f) {
4670 ERROR("Your system is not configured with subgids");
4671 return;
4672 }
4673
4674 while (getline(&line, &len, subgid_f) != -1) {
4675 char *p, *p2;
4676 size_t no_newline = 0;
4677
4678 p = strchr(line, ':');
4679 if (*line == '#')
4680 continue;
4681 if (!p)
4682 continue;
4683 *p = '\0';
4684 p++;
4685
4686 if (strcmp(line, uname))
4687 continue;
4688
4689 p2 = strchr(p, ':');
4690 if (!p2)
4691 continue;
4692 *p2 = '\0';
4693 p2++;
4694 if (!*p2)
4695 continue;
4696 no_newline = strcspn(p2, "\n");
4697 p2[no_newline] = '\0';
4698
4699 if (lxc_safe_uint(p, &gid) < 0)
4700 WARN("Could not parse GID");
4701 if (lxc_safe_uint(p2, &grange) < 0)
4702 WARN("Could not parse GID range");
4703 }
4704
4705 if (!urange || !grange) {
4706 ERROR("You do not have subuids or subgids allocated");
4707 ERROR("Unprivileged containers require subuids and subgids");
4708 return;
4709 }
4710
4711 ERROR("You must either run as root, or define uid mappings");
4712 ERROR("To pass uid mappings to lxc-create, you could create");
4713 ERROR("~/.config/lxc/default.conf:");
4714 ERROR("lxc.include = %s", LXC_DEFAULT_CONFIG);
4715 ERROR("lxc.idmap = u 0 %u %u", uid, urange);
4716 ERROR("lxc.idmap = g 0 %u %u", gid, grange);
4717 }
4718
4719 static void free_cgroup_settings(struct lxc_list *result)
4720 {
4721 struct lxc_list *iterator, *next;
4722
4723 lxc_list_for_each_safe (iterator, result, next) {
4724 lxc_list_del(iterator);
4725 free(iterator);
4726 }
4727 free(result);
4728 }
4729
4730 /* Return the list of cgroup_settings sorted according to the following rules
4731 * 1. Put memory.limit_in_bytes before memory.memsw.limit_in_bytes
4732 */
4733 struct lxc_list *sort_cgroup_settings(struct lxc_list *cgroup_settings)
4734 {
4735 struct lxc_list *result;
4736 struct lxc_cgroup *cg = NULL;
4737 struct lxc_list *it = NULL, *item = NULL, *memsw_limit = NULL;
4738
4739 result = malloc(sizeof(*result));
4740 if (!result)
4741 return NULL;
4742 lxc_list_init(result);
4743
4744 /* Iterate over the cgroup settings and copy them to the output list. */
4745 lxc_list_for_each (it, cgroup_settings) {
4746 item = malloc(sizeof(*item));
4747 if (!item) {
4748 free_cgroup_settings(result);
4749 return NULL;
4750 }
4751
4752 item->elem = it->elem;
4753 cg = it->elem;
4754 if (strcmp(cg->subsystem, "memory.memsw.limit_in_bytes") == 0) {
4755 /* Store the memsw_limit location */
4756 memsw_limit = item;
4757 } else if (strcmp(cg->subsystem, "memory.limit_in_bytes") == 0 &&
4758 memsw_limit != NULL) {
4759 /* lxc.cgroup.memory.memsw.limit_in_bytes is found
4760 * before lxc.cgroup.memory.limit_in_bytes, swap these
4761 * two items */
4762 item->elem = memsw_limit->elem;
4763 memsw_limit->elem = it->elem;
4764 }
4765 lxc_list_add_tail(result, item);
4766 }
4767
4768 return result;
4769 }
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