1 /* SPDX-License-Identifier: LGPL-2.1+ */
13 #include <linux/loop.h>
15 #include <netinet/in.h>
23 #include <sys/mount.h>
24 #include <sys/param.h>
25 #include <sys/prctl.h>
26 #include <sys/sendfile.h>
27 #include <sys/socket.h>
29 #include <sys/syscall.h>
30 #include <sys/sysmacros.h>
31 #include <sys/types.h>
32 #include <sys/utsname.h>
39 #include "cgroups/cgroup.h"
44 #include "confile_utils.h"
49 #include "lxcseccomp.h"
51 #include "memory_utils.h"
52 #include "mount_utils.h"
53 #include "namespace.h"
56 #include "process_utils.h"
59 #include "storage/storage.h"
60 #include "storage/overlay.h"
62 #include "syscall_wrappers.h"
68 #include <sys/mkdev.h>
72 #include <sys/statvfs.h>
78 #include <../include/openpty.h>
82 #include <sys/capability.h>
86 #include "include/strlcat.h"
90 #include <../include/lxcmntent.h>
95 #if !defined(HAVE_PRLIMIT) && defined(HAVE_PRLIMIT64)
96 #include <../include/prlimit.h>
100 #include "include/strlcpy.h"
103 #ifndef HAVE_STRCHRNUL
104 #include "include/strchrnul.h"
107 lxc_log_define(conf
, lxc
);
110 * The lxc_conf of the container currently being worked on in an API call.
111 * This is used in the error calls.
113 thread_local
struct lxc_conf
*current_config
;
115 char *lxchook_names
[NUM_LXC_HOOKS
] = {
146 static struct mount_opt mount_opt
[] = {
147 { "atime", 1, false, MOUNT_ATTR_NOATIME
, MS_NOATIME
},
148 { "dev", 1, false, MOUNT_ATTR_NODEV
, MS_NODEV
},
149 { "diratime", 1, false, MOUNT_ATTR_NODIRATIME
, MS_NODIRATIME
},
150 { "exec", 1, false, MOUNT_ATTR_NOEXEC
, MS_NOEXEC
},
151 { "noatime", 0, false, MOUNT_ATTR_NOATIME
, MS_NOATIME
},
152 { "nodev", 0, false, MOUNT_ATTR_NODEV
, MS_NODEV
},
153 { "nodiratime", 0, false, MOUNT_ATTR_NODIRATIME
, MS_NODIRATIME
},
154 { "noexec", 0, false, MOUNT_ATTR_NOEXEC
, MS_NOEXEC
},
155 { "norelatime", 1, false, MOUNT_ATTR_RELATIME
, MS_RELATIME
},
156 { "nostrictatime", 1, false, MOUNT_ATTR_STRICTATIME
, MS_STRICTATIME
},
157 { "nosuid", 0, false, MOUNT_ATTR_NOSUID
, MS_NOSUID
},
158 { "relatime", 0, false, MOUNT_ATTR_RELATIME
, MS_RELATIME
},
159 { "ro", 0, false, MOUNT_ATTR_RDONLY
, MS_RDONLY
},
160 { "rw", 1, false, MOUNT_ATTR_RDONLY
, MS_RDONLY
},
161 { "strictatime", 0, false, MOUNT_ATTR_STRICTATIME
, MS_STRICTATIME
},
162 { "suid", 1, false, MOUNT_ATTR_NOSUID
, MS_NOSUID
},
164 { "bind", 0, false, 0, MS_BIND
},
165 { "defaults", 0, false, 0, 0 },
166 { "rbind", 0, true, 0, MS_BIND
| MS_REC
},
168 { "sync", 0, false, ~0, MS_SYNCHRONOUS
},
169 { "async", 1, false, ~0, MS_SYNCHRONOUS
},
170 { "dirsync", 0, false, ~0, MS_DIRSYNC
},
171 { "lazytime", 0, false, ~0, MS_LAZYTIME
},
172 { "mand", 0, false, ~0, MS_MANDLOCK
},
173 { "nomand", 1, false, ~0, MS_MANDLOCK
},
174 { "remount", 0, false, ~0, MS_REMOUNT
},
176 { NULL
, 0, false, ~0, ~0 },
179 static struct mount_opt propagation_opt
[] = {
180 { "private", 0, false, MS_PRIVATE
, MS_PRIVATE
},
181 { "shared", 0, false, MS_SHARED
, MS_SHARED
},
182 { "slave", 0, false, MS_SLAVE
, MS_SLAVE
},
183 { "unbindable", 0, false, MS_UNBINDABLE
, MS_UNBINDABLE
},
184 { "rprivate", 0, true, MS_PRIVATE
, MS_PRIVATE
| MS_REC
},
185 { "rshared", 0, true, MS_SHARED
, MS_SHARED
| MS_REC
},
186 { "rslave", 0, true, MS_SLAVE
, MS_SLAVE
| MS_REC
},
187 { "runbindable", 0, true, MS_UNBINDABLE
, MS_UNBINDABLE
| MS_REC
},
191 static struct caps_opt caps_opt
[] = {
193 { "chown", CAP_CHOWN
},
194 { "dac_override", CAP_DAC_OVERRIDE
},
195 { "dac_read_search", CAP_DAC_READ_SEARCH
},
196 { "fowner", CAP_FOWNER
},
197 { "fsetid", CAP_FSETID
},
198 { "kill", CAP_KILL
},
199 { "setgid", CAP_SETGID
},
200 { "setuid", CAP_SETUID
},
201 { "setpcap", CAP_SETPCAP
},
202 { "linux_immutable", CAP_LINUX_IMMUTABLE
},
203 { "net_bind_service", CAP_NET_BIND_SERVICE
},
204 { "net_broadcast", CAP_NET_BROADCAST
},
205 { "net_admin", CAP_NET_ADMIN
},
206 { "net_raw", CAP_NET_RAW
},
207 { "ipc_lock", CAP_IPC_LOCK
},
208 { "ipc_owner", CAP_IPC_OWNER
},
209 { "sys_module", CAP_SYS_MODULE
},
210 { "sys_rawio", CAP_SYS_RAWIO
},
211 { "sys_chroot", CAP_SYS_CHROOT
},
212 { "sys_ptrace", CAP_SYS_PTRACE
},
213 { "sys_pacct", CAP_SYS_PACCT
},
214 { "sys_admin", CAP_SYS_ADMIN
},
215 { "sys_boot", CAP_SYS_BOOT
},
216 { "sys_nice", CAP_SYS_NICE
},
217 { "sys_resource", CAP_SYS_RESOURCE
},
218 { "sys_time", CAP_SYS_TIME
},
219 { "sys_tty_config", CAP_SYS_TTY_CONFIG
},
220 { "mknod", CAP_MKNOD
},
221 { "lease", CAP_LEASE
},
222 { "audit_write", CAP_AUDIT_WRITE
},
223 { "audit_control", CAP_AUDIT_CONTROL
},
224 { "setfcap", CAP_SETFCAP
},
225 { "mac_override", CAP_MAC_OVERRIDE
},
226 { "mac_admin", CAP_MAC_ADMIN
},
227 { "syslog", CAP_SYSLOG
},
228 { "wake_alarm", CAP_WAKE_ALARM
},
229 { "block_suspend", CAP_BLOCK_SUSPEND
},
230 { "audit_read", CAP_AUDIT_READ
},
231 { "perfmon", CAP_PERFMON
},
233 { "checkpoint_restore", CAP_CHECKPOINT_RESTORE
},
237 static struct limit_opt limit_opt
[] = {
242 { "core", RLIMIT_CORE
},
245 { "cpu", RLIMIT_CPU
},
248 { "data", RLIMIT_DATA
},
251 { "fsize", RLIMIT_FSIZE
},
254 { "locks", RLIMIT_LOCKS
},
256 #ifdef RLIMIT_MEMLOCK
257 { "memlock", RLIMIT_MEMLOCK
},
259 #ifdef RLIMIT_MSGQUEUE
260 { "msgqueue", RLIMIT_MSGQUEUE
},
263 { "nice", RLIMIT_NICE
},
266 { "nofile", RLIMIT_NOFILE
},
269 { "nproc", RLIMIT_NPROC
},
272 { "rss", RLIMIT_RSS
},
275 { "rtprio", RLIMIT_RTPRIO
},
278 { "rttime", RLIMIT_RTTIME
},
280 #ifdef RLIMIT_SIGPENDING
281 { "sigpending", RLIMIT_SIGPENDING
},
284 { "stack", RLIMIT_STACK
},
288 static int run_buffer(char *buffer
)
290 __do_free
char *output
= NULL
;
291 __do_lxc_pclose
struct lxc_popen_FILE
*f
= NULL
;
294 f
= lxc_popen(buffer
);
296 return log_error_errno(-1, errno
, "Failed to popen() %s", buffer
);
298 output
= zalloc(LXC_LOG_BUFFER_SIZE
);
300 return log_error_errno(-1, ENOMEM
, "Failed to allocate memory for %s", buffer
);
304 return log_error_errno(-1, errno
, "Failed to retrieve underlying file descriptor");
306 for (int i
= 0; i
< 10; i
++) {
309 bytes_read
= lxc_read_nointr(fd
, output
, LXC_LOG_BUFFER_SIZE
- 1);
310 if (bytes_read
> 0) {
311 output
[bytes_read
] = '\0';
312 DEBUG("Script %s produced output: %s", buffer
, output
);
319 ret
= lxc_pclose(move_ptr(f
));
321 return log_error_errno(-1, errno
, "Script exited with error");
322 else if (WIFEXITED(ret
) && WEXITSTATUS(ret
) != 0)
323 return log_error(-1, "Script exited with status %d", WEXITSTATUS(ret
));
324 else if (WIFSIGNALED(ret
))
325 return log_error(-1, "Script terminated by signal %d", WTERMSIG(ret
));
330 int run_script_argv(const char *name
, unsigned int hook_version
,
331 const char *section
, const char *script
,
332 const char *hookname
, char **argv
)
334 __do_free
char *buffer
= NULL
;
338 if (hook_version
== 0)
339 INFO("Executing script \"%s\" for container \"%s\", config section \"%s\"",
340 script
, name
, section
);
342 INFO("Executing script \"%s\" for container \"%s\"", script
, name
);
344 for (i
= 0; argv
&& argv
[i
]; i
++)
345 size
+= strlen(argv
[i
]) + 1;
347 size
+= STRLITERALLEN("exec");
349 size
+= strlen(script
);
355 if (hook_version
== 0) {
356 size
+= strlen(hookname
);
359 size
+= strlen(name
);
362 size
+= strlen(section
);
369 buffer
= zalloc(size
);
373 if (hook_version
== 0)
374 buf_pos
= strnprintf(buffer
, size
, "exec %s %s %s %s", script
, name
, section
, hookname
);
376 buf_pos
= strnprintf(buffer
, size
, "exec %s", script
);
378 return log_error_errno(-1, errno
, "Failed to create command line for script \"%s\"", script
);
380 if (hook_version
== 1) {
381 ret
= setenv("LXC_HOOK_TYPE", hookname
, 1);
383 return log_error_errno(-1, errno
, "Failed to set environment variable: LXC_HOOK_TYPE=%s", hookname
);
385 TRACE("Set environment variable: LXC_HOOK_TYPE=%s", hookname
);
387 ret
= setenv("LXC_HOOK_SECTION", section
, 1);
389 return log_error_errno(-1, errno
, "Failed to set environment variable: LXC_HOOK_SECTION=%s", section
);
390 TRACE("Set environment variable: LXC_HOOK_SECTION=%s", section
);
392 if (strequal(section
, "net")) {
395 if (!argv
|| !argv
[0])
398 ret
= setenv("LXC_NET_TYPE", argv
[0], 1);
400 return log_error_errno(-1, errno
, "Failed to set environment variable: LXC_NET_TYPE=%s", argv
[0]);
401 TRACE("Set environment variable: LXC_NET_TYPE=%s", argv
[0]);
403 parent
= argv
[1] ? argv
[1] : "";
405 if (strequal(argv
[0], "macvlan")) {
406 ret
= setenv("LXC_NET_PARENT", parent
, 1);
408 return log_error_errno(-1, errno
, "Failed to set environment variable: LXC_NET_PARENT=%s", parent
);
409 TRACE("Set environment variable: LXC_NET_PARENT=%s", parent
);
410 } else if (strequal(argv
[0], "phys")) {
411 ret
= setenv("LXC_NET_PARENT", parent
, 1);
413 return log_error_errno(-1, errno
, "Failed to set environment variable: LXC_NET_PARENT=%s", parent
);
414 TRACE("Set environment variable: LXC_NET_PARENT=%s", parent
);
415 } else if (strequal(argv
[0], "veth")) {
416 char *peer
= argv
[2] ? argv
[2] : "";
418 ret
= setenv("LXC_NET_PEER", peer
, 1);
420 return log_error_errno(-1, errno
, "Failed to set environment variable: LXC_NET_PEER=%s", peer
);
421 TRACE("Set environment variable: LXC_NET_PEER=%s", peer
);
423 ret
= setenv("LXC_NET_PARENT", parent
, 1);
425 return log_error_errno(-1, errno
, "Failed to set environment variable: LXC_NET_PARENT=%s", parent
);
426 TRACE("Set environment variable: LXC_NET_PARENT=%s", parent
);
431 for (i
= 0; argv
&& argv
[i
]; i
++) {
432 size_t len
= size
- buf_pos
;
434 ret
= strnprintf(buffer
+ buf_pos
, len
, " %s", argv
[i
]);
436 return log_error_errno(-1, errno
, "Failed to create command line for script \"%s\"", script
);
440 return run_buffer(buffer
);
443 int run_script(const char *name
, const char *section
, const char *script
, ...)
445 __do_free
char *buffer
= NULL
;
451 INFO("Executing script \"%s\" for container \"%s\", config section \"%s\"",
452 script
, name
, section
);
454 va_start(ap
, script
);
455 while ((p
= va_arg(ap
, char *)))
456 size
+= strlen(p
) + 1;
459 size
+= STRLITERALLEN("exec");
460 size
+= strlen(script
);
461 size
+= strlen(name
);
462 size
+= strlen(section
);
468 buffer
= must_realloc(NULL
, size
);
469 ret
= strnprintf(buffer
, size
, "exec %s %s %s", script
, name
, section
);
473 va_start(ap
, script
);
474 while ((p
= va_arg(ap
, char *))) {
475 int len
= size
- ret
;
477 rc
= strnprintf(buffer
+ ret
, len
, " %s", p
);
486 return run_buffer(buffer
);
489 int lxc_storage_prepare(struct lxc_conf
*conf
)
492 struct lxc_rootfs
*rootfs
= &conf
->rootfs
;
495 ret
= mount("", "/", NULL
, MS_SLAVE
| MS_REC
, 0);
497 return log_error_errno(-1, errno
, "Failed to recursively turn root mount tree into dependent mount");
499 rootfs
->dfd_mnt
= open_at(-EBADF
, "/", PROTECT_OPATH_DIRECTORY
, PROTECT_LOOKUP_ABSOLUTE
, 0);
500 if (rootfs
->dfd_mnt
< 0)
506 ret
= access(rootfs
->mount
, F_OK
);
508 return log_error_errno(-1, errno
, "Failed to access to \"%s\". Check it is present",
511 rootfs
->storage
= storage_init(conf
);
512 if (!rootfs
->storage
)
513 return log_error(-1, "Failed to mount rootfs \"%s\" onto \"%s\" with options \"%s\"",
514 rootfs
->path
, rootfs
->mount
,
515 rootfs
->mnt_opts
.raw_options
? rootfs
->mnt_opts
.raw_options
: "(null)");
520 void lxc_storage_put(struct lxc_conf
*conf
)
522 storage_put(conf
->rootfs
.storage
);
523 conf
->rootfs
.storage
= NULL
;
526 /* lxc_rootfs_prepare
527 * if rootfs is a directory, then open ${rootfs}/.lxc-keep for writing for
528 * the duration of the container run, to prevent the container from marking
529 * the underlying fs readonly on shutdown. unlink the file immediately so
530 * no name pollution is happens.
531 * don't unlink on NFS to avoid random named stale handles.
533 int lxc_rootfs_init(struct lxc_conf
*conf
, bool userns
)
535 __do_close
int dfd_path
= -EBADF
, fd_pin
= -EBADF
;
539 struct lxc_rootfs
*rootfs
= &conf
->rootfs
;
541 ret
= lxc_storage_prepare(conf
);
543 return syserror_set(-EINVAL
, "Failed to prepare rootfs storage");
545 if (!is_empty_string(rootfs
->mnt_opts
.userns_path
)) {
547 return syserror_set(-EINVAL
, "Idmapped rootfs currently only supported with separate rootfs for container");
549 if (rootfs
->bdev_type
&& !strequal(rootfs
->bdev_type
, "dir"))
550 return syserror_set(-EINVAL
, "Idmapped rootfs currently only supports the \"dir\" storage driver");
554 return log_trace(0, "Not pinning because container does not have a rootfs");
557 return log_trace(0, "Not pinning because container runs in user namespace");
559 if (rootfs
->bdev_type
) {
560 if (strequal(rootfs
->bdev_type
, "overlay") ||
561 strequal(rootfs
->bdev_type
, "overlayfs"))
562 return log_trace_errno(0, EINVAL
, "Not pinning on stacking filesystem");
564 if (strequal(rootfs
->bdev_type
, "zfs"))
565 return log_trace_errno(0, EINVAL
, "Not pinning on ZFS filesystem");
568 dfd_path
= open_at(-EBADF
, rootfs
->path
, PROTECT_OPATH_FILE
, 0, 0);
570 return syserror("Failed to open \"%s\"", rootfs
->path
);
572 ret
= fstat(dfd_path
, &st
);
574 return log_trace_errno(-errno
, errno
, "Failed to retrieve file status");
576 if (!S_ISDIR(st
.st_mode
))
577 return log_trace_errno(0, ENOTDIR
, "Not pinning because file descriptor is not a directory");
579 fd_pin
= open_at(dfd_path
, ".lxc_keep",
580 PROTECT_OPEN
| O_CREAT
,
581 PROTECT_LOOKUP_BENEATH
,
584 if (errno
== EROFS
) {
585 return log_trace_errno(0, EROFS
, "Not pinning on read-only filesystem");
587 return syserror("Failed to pin rootfs");
590 TRACE("Pinned rootfs %d(.lxc_keep)", fd_pin
);
592 ret
= fstatfs(fd_pin
, &stfs
);
594 SYSWARN("Failed to retrieve filesystem status");
598 if (stfs
.f_type
== NFS_SUPER_MAGIC
) {
599 DEBUG("Not unlinking pinned file on NFS");
603 if (unlinkat(dfd_path
, ".lxc_keep", 0))
604 SYSTRACE("Failed to unlink rootfs pinning file %d(.lxc_keep)", dfd_path
);
606 TRACE("Unlinked pinned file %d(.lxc_keep)", dfd_path
);
609 rootfs
->fd_path_pin
= move_fd(fd_pin
);
613 int lxc_rootfs_prepare_parent(struct lxc_handler
*handler
)
615 __do_close
int dfd_idmapped
= -EBADF
, fd_userns
= -EBADF
;
616 struct lxc_rootfs
*rootfs
= &handler
->conf
->rootfs
;
617 struct lxc_storage
*storage
= rootfs
->storage
;
618 const struct lxc_mount_options
*mnt_opts
= &rootfs
->mnt_opts
;
620 const char *path_source
;
622 if (list_empty(&handler
->conf
->id_map
))
625 if (is_empty_string(rootfs
->mnt_opts
.userns_path
))
628 if (handler
->conf
->rootfs_setup
)
631 if (rootfs_is_blockdev(handler
->conf
))
632 return syserror_set(-EOPNOTSUPP
, "Idmapped mounts on block-backed storage not yet supported");
634 if (!can_use_bind_mounts())
635 return syserror_set(-EOPNOTSUPP
, "Kernel does not support the new mount api");
637 if (strequal(rootfs
->mnt_opts
.userns_path
, "container"))
638 fd_userns
= dup_cloexec(handler
->nsfd
[LXC_NS_USER
]);
640 fd_userns
= open_at(-EBADF
, rootfs
->mnt_opts
.userns_path
,
641 PROTECT_OPEN_WITH_TRAILING_SYMLINKS
, 0, 0);
643 return syserror("Failed to open user namespace");
645 path_source
= lxc_storage_get_path(storage
->src
, storage
->type
);
647 dfd_idmapped
= create_detached_idmapped_mount(path_source
, fd_userns
, true,
648 mnt_opts
->attr
.attr_set
,
649 mnt_opts
->attr
.attr_clr
);
650 if (dfd_idmapped
< 0)
651 return syserror("Failed to create detached idmapped mount");
653 ret
= lxc_abstract_unix_send_fds(handler
->data_sock
[0], &dfd_idmapped
, 1, NULL
, 0);
655 return syserror("Failed to send detached idmapped mount fd");
657 TRACE("Created detached idmapped mount %d", dfd_idmapped
);
661 static int add_shmount_to_list(struct lxc_conf
*conf
)
663 char new_mount
[PATH_MAX
];
664 /* Offset for the leading '/' since the path_cont
665 * is absolute inside the container.
667 int offset
= 1, ret
= -1;
669 ret
= strnprintf(new_mount
, sizeof(new_mount
),
670 "%s %s none bind,create=dir 0 0", conf
->shmount
.path_host
,
671 conf
->shmount
.path_cont
+ offset
);
675 return add_elem_to_mount_list(new_mount
, conf
);
678 static int lxc_mount_auto_mounts(struct lxc_handler
*handler
, int flags
)
685 const char *destination
;
689 bool requires_cap_net_admin
;
690 } default_mounts
[] = {
691 /* Read-only bind-mounting... In older kernels, doing that
692 * required to do one MS_BIND mount and then
693 * MS_REMOUNT|MS_RDONLY the same one. According to mount(2)
694 * manpage, MS_BIND honors MS_RDONLY from kernel 2.6.26
695 * onwards. However, this apparently does not work on kernel
696 * 3.8. Unfortunately, on that very same kernel, doing the same
697 * trick as above doesn't seem to work either, there one needs
698 * to ALSO specify MS_BIND for the remount, otherwise the
699 * entire fs is remounted read-only or the mount fails because
700 * it's busy... MS_REMOUNT|MS_BIND|MS_RDONLY seems to work for
701 * kernels as low as 2.6.32...
703 { LXC_AUTO_PROC_MASK
, LXC_AUTO_PROC_MIXED
, "proc", "%r/proc", "proc", MS_NODEV
|MS_NOEXEC
|MS_NOSUID
, NULL
, false },
704 /* proc/tty is used as a temporary placeholder for proc/sys/net which we'll move back in a few steps */
705 { LXC_AUTO_PROC_MASK
, LXC_AUTO_PROC_MIXED
, "%r/proc/sys/net", "%r/proc/tty", NULL
, MS_BIND
, NULL
, true, },
706 { LXC_AUTO_PROC_MASK
, LXC_AUTO_PROC_MIXED
, "%r/proc/sys", "%r/proc/sys", NULL
, MS_BIND
, NULL
, false },
707 { LXC_AUTO_PROC_MASK
, LXC_AUTO_PROC_MIXED
, NULL
, "%r/proc/sys", NULL
, MS_REMOUNT
|MS_BIND
|MS_RDONLY
, NULL
, false },
708 { LXC_AUTO_PROC_MASK
, LXC_AUTO_PROC_MIXED
, "%r/proc/tty", "%r/proc/sys/net", NULL
, MS_MOVE
, NULL
, true },
709 { LXC_AUTO_PROC_MASK
, LXC_AUTO_PROC_MIXED
, "%r/proc/sysrq-trigger", "%r/proc/sysrq-trigger", NULL
, MS_BIND
, NULL
, false },
710 { LXC_AUTO_PROC_MASK
, LXC_AUTO_PROC_MIXED
, NULL
, "%r/proc/sysrq-trigger", NULL
, MS_REMOUNT
|MS_BIND
|MS_RDONLY
, NULL
, false },
711 { LXC_AUTO_PROC_MASK
, LXC_AUTO_PROC_RW
, "proc", "%r/proc", "proc", MS_NODEV
|MS_NOEXEC
|MS_NOSUID
, NULL
, false },
712 { LXC_AUTO_SYS_MASK
, LXC_AUTO_SYS_RW
, "sysfs", "%r/sys", "sysfs", 0, NULL
, false },
713 { LXC_AUTO_SYS_MASK
, LXC_AUTO_SYS_RO
, "sysfs", "%r/sys", "sysfs", MS_RDONLY
, NULL
, false },
714 { LXC_AUTO_SYS_MASK
, LXC_AUTO_SYS_MIXED
, "sysfs", "%r/sys", "sysfs", MS_RDONLY
|MS_NOSUID
|MS_NODEV
|MS_NOEXEC
, NULL
, false },
715 { LXC_AUTO_SYS_MASK
, LXC_AUTO_SYS_MIXED
, "%r/sys/devices/virtual/net", "%r/sys/devices/virtual/net", NULL
, MS_BIND
, NULL
, false },
716 { LXC_AUTO_SYS_MASK
, LXC_AUTO_SYS_MIXED
, NULL
, "%r/sys/devices/virtual/net", NULL
, MS_REMOUNT
|MS_NOSUID
|MS_NODEV
|MS_NOEXEC
, NULL
, false },
717 { 0, 0, NULL
, NULL
, NULL
, 0, NULL
, false }
719 struct lxc_conf
*conf
= handler
->conf
;
720 struct lxc_rootfs
*rootfs
= &conf
->rootfs
;
721 bool has_cap_net_admin
;
723 if (flags
& LXC_AUTO_PROC_MASK
) {
726 * Only unmount procfs if we have a separate rootfs so
727 * we can still access it in safe_mount() below.
729 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "%s/proc",
730 rootfs
->path
? rootfs
->mount
: "");
732 return ret_errno(EIO
);
734 ret
= umount2(rootfs
->buf
, MNT_DETACH
);
736 SYSDEBUG("Tried to ensure procfs is unmounted");
739 ret
= mkdirat(rootfs
->dfd_mnt
, "proc" , S_IRWXU
| S_IRGRP
| S_IXGRP
| S_IROTH
| S_IXOTH
);
740 if (ret
< 0 && errno
!= EEXIST
)
741 return syserror("Failed to create procfs mountpoint under %d", rootfs
->dfd_mnt
);
743 TRACE("Created procfs mountpoint under %d", rootfs
->dfd_mnt
);
746 if (flags
& LXC_AUTO_SYS_MASK
) {
749 * Only unmount sysfs if we have a separate rootfs so
750 * we can still access it in safe_mount() below.
752 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "%s/sys",
753 rootfs
->path
? rootfs
->mount
: "");
755 return ret_errno(EIO
);
757 ret
= umount2(rootfs
->buf
, MNT_DETACH
);
759 SYSDEBUG("Tried to ensure sysfs is unmounted");
762 ret
= mkdirat(rootfs
->dfd_mnt
, "sys" , S_IRWXU
| S_IRGRP
| S_IXGRP
| S_IROTH
| S_IXOTH
);
763 if (ret
< 0 && errno
!= EEXIST
)
764 return syserror("Failed to create sysfs mountpoint under %d", rootfs
->dfd_mnt
);
766 TRACE("Created sysfs mountpoint under %d", rootfs
->dfd_mnt
);
769 has_cap_net_admin
= lxc_wants_cap(CAP_NET_ADMIN
, conf
);
770 for (i
= 0; default_mounts
[i
].match_mask
; i
++) {
771 __do_free
char *destination
= NULL
, *source
= NULL
;
772 unsigned long mflags
= default_mounts
[i
].flags
;
774 if ((flags
& default_mounts
[i
].match_mask
) != default_mounts
[i
].match_flag
)
777 if (default_mounts
[i
].source
) {
778 /* will act like strdup if %r is not present */
779 source
= lxc_string_replace("%r", rootfs
->path
? rootfs
->mount
: "", default_mounts
[i
].source
);
781 return syserror_set(-ENOMEM
, "Failed to create source path");
784 if (!default_mounts
[i
].destination
)
785 return syserror_set(-EINVAL
, "BUG: auto mounts destination %d was NULL", i
);
787 if (!has_cap_net_admin
&& default_mounts
[i
].requires_cap_net_admin
) {
788 TRACE("Container does not have CAP_NET_ADMIN. Skipping \"%s\" mount", default_mounts
[i
].source
?: "(null)");
792 /* will act like strdup if %r is not present */
793 destination
= lxc_string_replace("%r", rootfs
->path
? rootfs
->mount
: "", default_mounts
[i
].destination
);
795 return syserror_set(-ENOMEM
, "Failed to create target path");
797 ret
= safe_mount(source
, destination
,
798 default_mounts
[i
].fstype
,
800 default_mounts
[i
].options
,
801 rootfs
->path
? rootfs
->mount
: NULL
);
804 return syserror("Failed to mount \"%s\" on \"%s\" with flags %lu", source
, destination
, mflags
);
806 INFO("Mount source or target for \"%s\" on \"%s\" does not exist. Skipping", source
, destination
);
810 if (mflags
& MS_REMOUNT
)
811 TRACE("Remounted automount \"%s\" on \"%s\" %s with flags %lu", source
, destination
, (mflags
& MS_RDONLY
) ? "read-only" : "read-write", mflags
);
813 TRACE("Mounted automount \"%s\" on \"%s\" %s with flags %lu", source
, destination
, (mflags
& MS_RDONLY
) ? "read-only" : "read-write", mflags
);
816 if (flags
& LXC_AUTO_CGROUP_MASK
) {
819 cg_flags
= flags
& (LXC_AUTO_CGROUP_MASK
& ~LXC_AUTO_CGROUP_FORCE
);
820 /* If the type of cgroup mount was not specified, it depends on
821 * the container's capabilities as to what makes sense: if we
822 * have CAP_SYS_ADMIN, the read-only part can be remounted
823 * read-write anyway, so we may as well default to read-write;
824 * then the admin will not be given a false sense of security.
825 * (And if they really want mixed r/o r/w, then they can
826 * explicitly specify :mixed.) OTOH, if the container lacks
827 * CAP_SYS_ADMIN, do only default to :mixed, because then the
828 * container can't remount it read-write.
830 if ((cg_flags
== LXC_AUTO_CGROUP_NOSPEC
) || (cg_flags
== LXC_AUTO_CGROUP_FULL_NOSPEC
)) {
831 int has_sys_admin
= 0;
833 if (!lxc_list_empty(&conf
->keepcaps
))
834 has_sys_admin
= in_caplist(CAP_SYS_ADMIN
, &conf
->keepcaps
);
836 has_sys_admin
= !in_caplist(CAP_SYS_ADMIN
, &conf
->caps
);
838 if (cg_flags
== LXC_AUTO_CGROUP_NOSPEC
)
839 cg_flags
= has_sys_admin
? LXC_AUTO_CGROUP_RW
: LXC_AUTO_CGROUP_MIXED
;
841 cg_flags
= has_sys_admin
? LXC_AUTO_CGROUP_FULL_RW
: LXC_AUTO_CGROUP_FULL_MIXED
;
844 if (flags
& LXC_AUTO_CGROUP_FORCE
)
845 cg_flags
|= LXC_AUTO_CGROUP_FORCE
;
847 if (!handler
->cgroup_ops
->mount(handler
->cgroup_ops
, handler
, cg_flags
))
848 return log_error_errno(-1, errno
, "Failed to mount \"/sys/fs/cgroup\"");
851 if (flags
& LXC_AUTO_SHMOUNTS_MASK
) {
852 ret
= add_shmount_to_list(conf
);
854 return log_error(-1, "Failed to add shmount entry to container config");
860 static int setup_utsname(struct utsname
*utsname
)
867 ret
= sethostname(utsname
->nodename
, strlen(utsname
->nodename
));
869 return log_error_errno(-1, errno
, "Failed to set the hostname to \"%s\"",
872 INFO("Set hostname to \"%s\"", utsname
->nodename
);
877 struct dev_symlinks
{
882 static const struct dev_symlinks dev_symlinks
[] = {
883 { "/proc/self/fd", "fd" },
884 { "/proc/self/fd/0", "stdin" },
885 { "/proc/self/fd/1", "stdout" },
886 { "/proc/self/fd/2", "stderr" },
889 static int lxc_setup_dev_symlinks(const struct lxc_rootfs
*rootfs
)
891 for (int i
= 0; i
< sizeof(dev_symlinks
) / sizeof(dev_symlinks
[0]); i
++) {
894 const struct dev_symlinks
*d
= &dev_symlinks
[i
];
897 * Stat the path first. If we don't get an error accept it as
898 * is and don't try to create it
900 ret
= fstatat(rootfs
->dfd_dev
, d
->name
, &s
, 0);
904 ret
= symlinkat(d
->oldpath
, rootfs
->dfd_dev
, d
->name
);
908 WARN("Failed to create \"%s\" on read-only filesystem", d
->name
);
913 return log_error_errno(-errno
, errno
, "Failed to create \"%s\"", d
->name
);
921 /* Build a space-separate list of ptys to pass to systemd. */
922 static bool append_ttyname(char **pp
, char *name
)
928 *pp
= zalloc(strlen(name
) + strlen("container_ttys=") + 1);
932 sprintf(*pp
, "container_ttys=%s", name
);
936 size
= strlen(*pp
) + strlen(name
) + 2;
937 p
= realloc(*pp
, size
);
942 (void)strlcat(p
, " ", size
);
943 (void)strlcat(p
, name
, size
);
948 static int open_ttymnt_at(int dfd
, const char *path
)
952 fd
= open_at(dfd
, path
,
953 PROTECT_OPEN
| O_CREAT
| O_EXCL
,
954 PROTECT_LOOKUP_BENEATH
,
957 if (!IN_SET(errno
, ENXIO
, EEXIST
))
958 return syserror("Failed to create \"%d/\%s\"", dfd
, path
);
960 SYSINFO("Failed to create \"%d/\%s\"", dfd
, path
);
961 fd
= open_at(dfd
, path
,
963 PROTECT_LOOKUP_BENEATH
,
970 static int lxc_setup_ttys(struct lxc_conf
*conf
)
973 struct lxc_rootfs
*rootfs
= &conf
->rootfs
;
974 const struct lxc_tty_info
*ttys
= &conf
->ttys
;
975 char *ttydir
= ttys
->dir
;
977 if (!conf
->rootfs
.path
)
980 for (int i
= 0; i
< ttys
->max
; i
++) {
981 __do_close
int fd_to
= -EBADF
;
982 struct lxc_terminal_info
*tty
= &ttys
->tty
[i
];
985 char *tty_name
, *tty_path
;
987 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
),
988 "/dev/%s/tty%d", ttydir
, i
+ 1);
990 return ret_errno(-EIO
);
992 tty_path
= &rootfs
->buf
[STRLITERALLEN("/dev/")];
993 tty_name
= tty_path
+ strlen(ttydir
) + 1;
995 /* create bind-mount target */
996 fd_to
= open_ttymnt_at(rootfs
->dfd_dev
, tty_path
);
998 return log_error_errno(-errno
, errno
,
999 "Failed to create tty mount target %d(%s)",
1000 rootfs
->dfd_dev
, tty_path
);
1002 ret
= unlinkat(rootfs
->dfd_dev
, tty_name
, 0);
1003 if (ret
< 0 && errno
!= ENOENT
)
1004 return log_error_errno(-errno
, errno
,
1005 "Failed to unlink %d(%s)",
1006 rootfs
->dfd_dev
, tty_name
);
1008 if (can_use_mount_api())
1009 ret
= fd_bind_mount(tty
->pty
, "",
1011 PROTECT_LOOKUP_BENEATH_XDEV
,
1014 PROTECT_LOOKUP_BENEATH_XDEV
,
1020 ret
= mount_fd(tty
->pty
, fd_to
, "none", MS_BIND
, 0);
1022 return log_error_errno(-errno
, errno
,
1023 "Failed to bind mount \"%s\" onto \"%s\"",
1024 tty
->name
, rootfs
->buf
);
1025 DEBUG("Bind mounted \"%s\" onto \"%s\"", tty
->name
, rootfs
->buf
);
1027 ret
= symlinkat(tty_path
, rootfs
->dfd_dev
, tty_name
);
1029 return log_error_errno(-errno
, errno
,
1030 "Failed to create symlink \"%d(%s)\" -> \"%d(%s)\"",
1031 rootfs
->dfd_dev
, tty_name
,
1032 rootfs
->dfd_dev
, tty_path
);
1034 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "tty%d", i
+ 1);
1036 return ret_errno(-EIO
);
1038 /* If we populated /dev, then we need to create /dev/tty<idx>. */
1039 fd_to
= open_ttymnt_at(rootfs
->dfd_dev
, rootfs
->buf
);
1041 return log_error_errno(-errno
, errno
,
1042 "Failed to create tty mount target %d(%s)",
1043 rootfs
->dfd_dev
, rootfs
->buf
);
1045 if (can_use_mount_api())
1046 ret
= fd_bind_mount(tty
->pty
, "",
1048 PROTECT_LOOKUP_BENEATH_XDEV
,
1051 PROTECT_LOOKUP_BENEATH
,
1057 ret
= mount_fd(tty
->pty
, fd_to
, "none", MS_BIND
, 0);
1059 return log_error_errno(-errno
, errno
,
1060 "Failed to bind mount \"%s\" onto \"%s\"",
1061 tty
->name
, rootfs
->buf
);
1062 DEBUG("Bind mounted \"%s\" onto \"%s\"", tty
->name
, rootfs
->buf
);
1065 if (!append_ttyname(&conf
->ttys
.tty_names
, tty
->name
))
1066 return log_error(-1, "Error setting up container_ttys string");
1069 INFO("Finished setting up %zu /dev/tty<N> device(s)", ttys
->max
);
1073 define_cleanup_function(struct lxc_tty_info
*, lxc_delete_tty
);
1075 static int lxc_allocate_ttys(struct lxc_conf
*conf
)
1077 call_cleaner(lxc_delete_tty
) struct lxc_tty_info
*ttys
= &conf
->ttys
;
1080 /* no tty in the configuration */
1084 ttys
->tty
= zalloc(sizeof(struct lxc_terminal_info
) * ttys
->max
);
1088 for (size_t i
= 0; i
< conf
->ttys
.max
; i
++) {
1090 struct lxc_terminal_info
*tty
= &ttys
->tty
[i
];
1092 ret
= lxc_devpts_terminal(conf
->devpts_fd
, &tty
->ptx
,
1093 &tty
->pty
, &pty_nr
, false);
1096 return syserror_set(-ENOTTY
, "Failed to create tty %zu", i
);
1098 DEBUG("Created tty with ptx fd %d and pty fd %d and index %d",
1099 tty
->ptx
, tty
->pty
, pty_nr
);
1103 INFO("Finished creating %zu tty devices", ttys
->max
);
1108 void lxc_delete_tty(struct lxc_tty_info
*ttys
)
1110 if (!ttys
|| !ttys
->tty
)
1113 for (int i
= 0; i
< ttys
->max
; i
++) {
1114 struct lxc_terminal_info
*tty
= &ttys
->tty
[i
];
1115 close_prot_errno_disarm(tty
->ptx
);
1116 close_prot_errno_disarm(tty
->pty
);
1119 free_disarm(ttys
->tty
);
1122 static int __lxc_send_ttys_to_parent(struct lxc_handler
*handler
)
1126 struct lxc_conf
*conf
= handler
->conf
;
1127 struct lxc_tty_info
*ttys
= &conf
->ttys
;
1128 int sock
= handler
->data_sock
[0];
1133 for (i
= 0; i
< ttys
->max
; i
++) {
1135 struct lxc_terminal_info
*tty
= &ttys
->tty
[i
];
1137 ttyfds
[0] = tty
->ptx
;
1138 ttyfds
[1] = tty
->pty
;
1140 ret
= lxc_abstract_unix_send_fds(sock
, ttyfds
, 2, NULL
, 0);
1144 TRACE("Sent tty \"%s\" with ptx fd %d and pty fd %d to parent",
1145 tty
->name
, tty
->ptx
, tty
->pty
);
1149 SYSERROR("Failed to send %zu ttys to parent", ttys
->max
);
1151 TRACE("Sent %zu ttys to parent", ttys
->max
);
1156 static int lxc_create_ttys(struct lxc_handler
*handler
)
1159 struct lxc_conf
*conf
= handler
->conf
;
1161 ret
= lxc_allocate_ttys(conf
);
1163 ERROR("Failed to allocate ttys");
1167 if (!conf
->is_execute
) {
1168 ret
= lxc_setup_ttys(conf
);
1170 ERROR("Failed to setup ttys");
1175 if (conf
->ttys
.tty_names
) {
1176 ret
= setenv("container_ttys", conf
->ttys
.tty_names
, 1);
1178 SYSERROR("Failed to set \"container_ttys=%s\"", conf
->ttys
.tty_names
);
1186 lxc_delete_tty(&conf
->ttys
);
1191 static int lxc_send_ttys_to_parent(struct lxc_handler
*handler
)
1195 ret
= __lxc_send_ttys_to_parent(handler
);
1196 lxc_delete_tty(&handler
->conf
->ttys
);
1200 /* Just create a path for /dev under $lxcpath/$name and in rootfs If we hit an
1201 * error, log it but don't fail yet.
1203 static int mount_autodev(const char *name
, const struct lxc_rootfs
*rootfs
,
1204 int autodevtmpfssize
, const char *lxcpath
)
1206 __do_close
int fd_fs
= -EBADF
;
1207 const char *path
= rootfs
->path
? rootfs
->mount
: NULL
;
1208 size_t tmpfs_size
= (autodevtmpfssize
!= 0) ? autodevtmpfssize
: 500000;
1211 char mount_options
[128];
1213 INFO("Preparing \"/dev\"");
1215 cur_mask
= umask(S_IXUSR
| S_IXGRP
| S_IXOTH
);
1216 ret
= mkdirat(rootfs
->dfd_mnt
, "dev" , S_IRWXU
| S_IRGRP
| S_IXGRP
| S_IROTH
| S_IXOTH
);
1217 if (ret
< 0 && errno
!= EEXIST
) {
1218 SYSERROR("Failed to create \"/dev\" directory");
1223 if (can_use_mount_api()) {
1224 fd_fs
= fs_prepare("tmpfs", -EBADF
, "", 0, 0);
1226 return log_error_errno(-errno
, errno
, "Failed to prepare filesystem context for tmpfs");
1228 sprintf(mount_options
, "%zu", tmpfs_size
);
1230 ret
= fs_set_property(fd_fs
, "mode", "0755");
1232 return log_error_errno(-errno
, errno
, "Failed to mount tmpfs onto %d(dev)", fd_fs
);
1234 ret
= fs_set_property(fd_fs
, "size", mount_options
);
1236 return log_error_errno(-errno
, errno
, "Failed to mount tmpfs onto %d(dev)", fd_fs
);
1238 ret
= fs_attach(fd_fs
, rootfs
->dfd_mnt
, "dev",
1239 PROTECT_OPATH_DIRECTORY
,
1240 PROTECT_LOOKUP_BENEATH_XDEV
, 0);
1242 __do_free
char *fallback_path
= NULL
;
1244 sprintf(mount_options
, "size=%zu,mode=755", tmpfs_size
);
1245 DEBUG("Using mount options: %s", mount_options
);
1248 fallback_path
= must_make_path(path
, "/dev", NULL
);
1249 ret
= safe_mount("none", fallback_path
, "tmpfs", 0, mount_options
, path
);
1251 ret
= safe_mount("none", "dev", "tmpfs", 0, mount_options
, NULL
);
1255 SYSERROR("Failed to mount tmpfs on \"%s\"", path
);
1259 /* If we are running on a devtmpfs mapping, dev/pts may already exist.
1260 * If not, then create it and exit if that fails...
1262 ret
= mkdirat(rootfs
->dfd_mnt
, "dev/pts", S_IRWXU
| S_IRGRP
| S_IXGRP
| S_IROTH
| S_IXOTH
);
1263 if (ret
< 0 && errno
!= EEXIST
) {
1264 SYSERROR("Failed to create directory \"dev/pts\"");
1272 (void)umask(cur_mask
);
1274 INFO("Prepared \"/dev\"");
1278 struct lxc_device_node
{
1285 static const struct lxc_device_node lxc_devices
[] = {
1286 { "full", S_IFCHR
| S_IRWXU
| S_IRWXG
| S_IRWXO
, 1, 7 },
1287 { "null", S_IFCHR
| S_IRWXU
| S_IRWXG
| S_IRWXO
, 1, 3 },
1288 { "random", S_IFCHR
| S_IRWXU
| S_IRWXG
| S_IRWXO
, 1, 8 },
1289 { "tty", S_IFCHR
| S_IRWXU
| S_IRWXG
| S_IRWXO
, 5, 0 },
1290 { "urandom", S_IFCHR
| S_IRWXU
| S_IRWXG
| S_IRWXO
, 1, 9 },
1291 { "zero", S_IFCHR
| S_IRWXU
| S_IRWXG
| S_IRWXO
, 1, 5 },
1298 LXC_DEVNODE_PARTIAL
,
1302 static int lxc_fill_autodev(struct lxc_rootfs
*rootfs
)
1306 int use_mknod
= LXC_DEVNODE_MKNOD
;
1308 if (rootfs
->dfd_dev
< 0)
1309 return log_info(0, "No /dev directory found, skipping setup");
1311 INFO("Populating \"/dev\"");
1313 cmask
= umask(S_IXUSR
| S_IXGRP
| S_IXOTH
);
1314 for (i
= 0; i
< sizeof(lxc_devices
) / sizeof(lxc_devices
[0]); i
++) {
1315 const struct lxc_device_node
*device
= &lxc_devices
[i
];
1317 if (use_mknod
>= LXC_DEVNODE_MKNOD
) {
1318 ret
= mknodat(rootfs
->dfd_dev
, device
->name
, device
->mode
, makedev(device
->maj
, device
->min
));
1319 if (ret
== 0 || (ret
< 0 && errno
== EEXIST
)) {
1320 DEBUG("Created device node \"%s\"", device
->name
);
1321 } else if (ret
< 0) {
1323 return log_error_errno(-1, errno
, "Failed to create device node \"%s\"", device
->name
);
1325 use_mknod
= LXC_DEVNODE_BIND
;
1328 /* Device nodes are fully useable. */
1329 if (use_mknod
== LXC_DEVNODE_OPEN
)
1332 if (use_mknod
== LXC_DEVNODE_MKNOD
) {
1333 __do_close
int fd
= -EBADF
;
1335 * - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=55956b59df336f6738da916dbb520b6e37df9fbd
1336 * - https://lists.linuxfoundation.org/pipermail/containers/2018-June/039176.html
1338 fd
= open_at(rootfs
->dfd_dev
, device
->name
, PROTECT_OPEN
, PROTECT_LOOKUP_BENEATH
, 0);
1340 /* Device nodes are fully useable. */
1341 use_mknod
= LXC_DEVNODE_OPEN
;
1345 SYSTRACE("Failed to open \"%s\" device", device
->name
);
1346 /* Device nodes are only partially useable. */
1347 use_mknod
= LXC_DEVNODE_PARTIAL
;
1351 if (use_mknod
!= LXC_DEVNODE_PARTIAL
) {
1352 /* If we are dealing with partially functional device
1353 * nodes the prio mknod() call will have created the
1354 * device node so we can use it as a bind-mount target.
1356 ret
= mknodat(rootfs
->dfd_dev
, device
->name
, S_IFREG
| 0000, 0);
1357 if (ret
< 0 && errno
!= EEXIST
)
1358 return log_error_errno(-1, errno
, "Failed to create file \"%s\"", device
->name
);
1361 /* Fallback to bind-mounting the device from the host. */
1362 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "dev/%s", device
->name
);
1364 return ret_errno(EIO
);
1366 if (can_use_mount_api()) {
1367 ret
= fd_bind_mount(rootfs
->dfd_host
, rootfs
->buf
,
1369 PROTECT_LOOKUP_BENEATH_XDEV
,
1370 rootfs
->dfd_dev
, device
->name
,
1372 PROTECT_LOOKUP_BENEATH
,
1378 char path
[PATH_MAX
];
1380 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "/dev/%s", device
->name
);
1382 return ret_errno(EIO
);
1384 ret
= strnprintf(path
, sizeof(path
), "%s/dev/%s", get_rootfs_mnt(rootfs
), device
->name
);
1386 return log_error(-1, "Failed to create device path for %s", device
->name
);
1388 ret
= safe_mount(rootfs
->buf
, path
, 0, MS_BIND
, NULL
, get_rootfs_mnt(rootfs
));
1390 return log_error_errno(-1, errno
, "Failed to bind mount host device node \"%s\" to \"%s\"", rootfs
->buf
, path
);
1392 DEBUG("Bind mounted host device node \"%s\" to \"%s\"", rootfs
->buf
, path
);
1395 DEBUG("Bind mounted host device %d(%s) to %d(%s)", rootfs
->dfd_host
, rootfs
->buf
, rootfs
->dfd_dev
, device
->name
);
1399 INFO("Populated \"/dev\"");
1403 static int lxc_mount_rootfs(struct lxc_rootfs
*rootfs
)
1407 if (!rootfs
->path
) {
1408 ret
= mount("", "/", NULL
, MS_SLAVE
| MS_REC
, 0);
1410 return log_error_errno(-1, errno
, "Failed to recursively turn root mount tree into dependent mount");
1412 rootfs
->dfd_mnt
= open_at(-EBADF
, "/", PROTECT_OPATH_DIRECTORY
, PROTECT_LOOKUP_ABSOLUTE
, 0);
1413 if (rootfs
->dfd_mnt
< 0)
1416 return log_trace(0, "Container doesn't use separate rootfs. Opened host's rootfs");
1419 ret
= access(rootfs
->mount
, F_OK
);
1421 return log_error_errno(-1, errno
, "Failed to access to \"%s\". Check it is present",
1424 ret
= rootfs
->storage
->ops
->mount(rootfs
->storage
);
1426 return log_error(-1, "Failed to mount rootfs \"%s\" onto \"%s\" with options \"%s\"",
1427 rootfs
->path
, rootfs
->mount
,
1428 rootfs
->mnt_opts
.raw_options
? rootfs
->mnt_opts
.raw_options
: "(null)");
1430 DEBUG("Mounted rootfs \"%s\" onto \"%s\" with options \"%s\"",
1431 rootfs
->path
, rootfs
->mount
,
1432 rootfs
->mnt_opts
.raw_options
? rootfs
->mnt_opts
.raw_options
: "(null)");
1434 rootfs
->dfd_mnt
= open_at(-EBADF
, rootfs
->mount
, PROTECT_OPATH_DIRECTORY
, PROTECT_LOOKUP_ABSOLUTE_XDEV
, 0);
1435 if (rootfs
->dfd_mnt
< 0)
1438 return log_trace(0, "Container uses separate rootfs. Opened container's rootfs");
1441 static int lxc_chroot(const struct lxc_rootfs
*rootfs
)
1443 __do_free
char *nroot
= NULL
;
1445 char *root
= rootfs
->mount
;
1447 nroot
= realpath(root
, NULL
);
1449 return log_error_errno(-1, errno
, "Failed to resolve \"%s\"", root
);
1455 /* We could use here MS_MOVE, but in userns this mount is locked and
1458 ret
= mount(nroot
, "/", NULL
, MS_REC
| MS_BIND
, NULL
);
1460 return log_error_errno(-1, errno
, "Failed to mount \"%s\" onto \"/\" as MS_REC | MS_BIND", nroot
);
1462 ret
= mount(NULL
, "/", NULL
, MS_REC
| MS_PRIVATE
, NULL
);
1464 return log_error_errno(-1, errno
, "Failed to remount \"/\"");
1466 /* The following code cleans up inherited mounts which are not required
1469 * The mountinfo file shows not all mounts, if a few points have been
1470 * unmounted between read operations from the mountinfo. So we need to
1471 * read mountinfo a few times.
1473 * This loop can be skipped if a container uses userns, because all
1474 * inherited mounts are locked and we should live with all this trash.
1477 __do_fclose
FILE *f
= NULL
;
1478 __do_free
char *line
= NULL
;
1479 char *slider1
, *slider2
;
1483 f
= fopen("./proc/self/mountinfo", "re");
1485 return log_error_errno(-1, errno
, "Failed to open \"/proc/self/mountinfo\"");
1487 while (getline(&line
, &len
, f
) > 0) {
1488 for (slider1
= line
, i
= 0; slider1
&& i
< 4; i
++)
1489 slider1
= strchr(slider1
+ 1, ' ');
1494 slider2
= strchr(slider1
+ 1, ' ');
1501 if (strequal(slider1
+ 1, "/"))
1504 if (strequal(slider1
+ 1, "/proc"))
1507 ret
= umount2(slider1
, MNT_DETACH
);
1516 /* This also can be skipped if a container uses userns. */
1517 (void)umount2("./proc", MNT_DETACH
);
1519 /* It is weird, but chdir("..") moves us in a new root */
1522 return log_error_errno(-1, errno
, "Failed to chdir(\"..\")");
1526 return log_error_errno(-1, errno
, "Failed to chroot(\".\")");
1531 /* (The following explanation is copied verbatim from the kernel.)
1533 * pivot_root Semantics:
1534 * Moves the root file system of the current process to the directory put_old,
1535 * makes new_root as the new root file system of the current process, and sets
1536 * root/cwd of all processes which had them on the current root to new_root.
1539 * The new_root and put_old must be directories, and must not be on the
1540 * same file system as the current process root. The put_old must be
1541 * underneath new_root, i.e. adding a non-zero number of /.. to the string
1542 * pointed to by put_old must yield the same directory as new_root. No other
1543 * file system may be mounted on put_old. After all, new_root is a mountpoint.
1545 * Also, the current root cannot be on the 'rootfs' (initial ramfs) filesystem.
1546 * See Documentation/filesystems/ramfs-rootfs-initramfs.txt for alternatives
1547 * in this situation.
1550 * - we don't move root/cwd if they are not at the root (reason: if something
1551 * cared enough to change them, it's probably wrong to force them elsewhere)
1552 * - it's okay to pick a root that isn't the root of a file system, e.g.
1553 * /nfs/my_root where /nfs is the mount point. It must be a mountpoint,
1554 * though, so you may need to say mount --bind /nfs/my_root /nfs/my_root
1557 static int lxc_pivot_root(const struct lxc_rootfs
*rootfs
)
1559 __do_close
int fd_oldroot
= -EBADF
;
1562 fd_oldroot
= open_at(-EBADF
, "/", PROTECT_OPATH_DIRECTORY
, PROTECT_LOOKUP_ABSOLUTE
, 0);
1564 return log_error_errno(-1, errno
, "Failed to open old root directory");
1566 /* change into new root fs */
1567 ret
= fchdir(rootfs
->dfd_mnt
);
1569 return log_error_errno(-errno
, errno
, "Failed to change into new root directory \"%s\"", rootfs
->mount
);
1571 /* pivot_root into our new root fs */
1572 ret
= pivot_root(".", ".");
1574 return log_error_errno(-errno
, errno
, "Failed to pivot into new root directory \"%s\"", rootfs
->mount
);
1576 /* At this point the old-root is mounted on top of our new-root. To
1577 * unmounted it we must not be chdir'd into it, so escape back to
1580 ret
= fchdir(fd_oldroot
);
1582 return log_error_errno(-errno
, errno
, "Failed to enter old root directory");
1585 * Make fd_oldroot a depedent mount to make sure our umounts don't
1586 * propagate to the host.
1588 ret
= mount("", ".", "", MS_SLAVE
| MS_REC
, NULL
);
1590 return log_error_errno(-errno
, errno
, "Failed to recursively turn old root mount tree into dependent mount");
1592 ret
= umount2(".", MNT_DETACH
);
1594 return log_error_errno(-errno
, errno
, "Failed to detach old root directory");
1596 ret
= fchdir(rootfs
->dfd_mnt
);
1598 return log_error_errno(-errno
, errno
, "Failed to re-enter new root directory \"%s\"", rootfs
->mount
);
1600 TRACE("Changed into new rootfs \"%s\"", rootfs
->mount
);
1604 static int lxc_setup_rootfs_switch_root(const struct lxc_rootfs
*rootfs
)
1607 return log_debug(0, "Container does not have a rootfs");
1609 if (detect_ramfs_rootfs())
1610 return lxc_chroot(rootfs
);
1612 return lxc_pivot_root(rootfs
);
1615 static const struct id_map
*find_mapped_nsid_entry(const struct lxc_conf
*conf
,
1620 struct id_map
*retmap
= NULL
;
1622 /* Shortcut for container's root mappings. */
1624 if (idtype
== ID_TYPE_UID
)
1625 return conf
->root_nsuid_map
;
1627 if (idtype
== ID_TYPE_GID
)
1628 return conf
->root_nsgid_map
;
1631 list_for_each_entry(map
, &conf
->id_map
, head
) {
1632 if (map
->idtype
!= idtype
)
1635 if (id
>= map
->nsid
&& id
< map
->nsid
+ map
->range
) {
1644 static int lxc_recv_devpts_from_child(struct lxc_handler
*handler
)
1648 if (handler
->conf
->pty_max
<= 0)
1651 ret
= lxc_abstract_unix_recv_one_fd(handler
->data_sock
[1],
1652 &handler
->conf
->devpts_fd
,
1653 &handler
->conf
->devpts_fd
,
1654 sizeof(handler
->conf
->devpts_fd
));
1656 return log_error_errno(-1, errno
, "Failed to receive devpts fd from child");
1658 TRACE("Received devpts file descriptor %d from child", handler
->conf
->devpts_fd
);
1662 static int lxc_setup_devpts_child(struct lxc_handler
*handler
)
1664 __do_close
int devpts_fd
= -EBADF
, fd_fs
= -EBADF
;
1665 struct lxc_conf
*conf
= handler
->conf
;
1666 struct lxc_rootfs
*rootfs
= &conf
->rootfs
;
1667 size_t pty_max
= conf
->pty_max
;
1670 pty_max
+= conf
->ttys
.max
;
1672 return log_debug(0, "No new devpts instance will be mounted since no pts devices are required");
1674 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
),
1675 "/proc/self/fd/%d/pts", rootfs
->dfd_dev
);
1677 return syserror("Failed to create path");
1679 (void)umount2(rootfs
->buf
, MNT_DETACH
);
1681 /* Create mountpoint for devpts instance. */
1682 ret
= mkdirat(rootfs
->dfd_dev
, "pts", 0755);
1683 if (ret
< 0 && errno
!= EEXIST
)
1684 return log_error_errno(-1, errno
, "Failed to create \"/dev/pts\" directory");
1686 if (can_use_mount_api()) {
1687 fd_fs
= fs_prepare("devpts", -EBADF
, "", 0, 0);
1689 return syserror("Failed to prepare filesystem context for devpts");
1691 ret
= fs_set_property(fd_fs
, "source", "devpts");
1693 SYSTRACE("Failed to set \"source=devpts\" on devpts filesystem context %d", fd_fs
);
1695 ret
= fs_set_property(fd_fs
, "gid", "5");
1697 SYSTRACE("Failed to set \"gid=5\" on devpts filesystem context %d", fd_fs
);
1699 ret
= fs_set_flag(fd_fs
, "newinstance");
1701 return syserror("Failed to set \"newinstance\" property on devpts filesystem context %d", fd_fs
);
1703 ret
= fs_set_property(fd_fs
, "ptmxmode", "0666");
1705 return syserror("Failed to set \"ptmxmode=0666\" property on devpts filesystem context %d", fd_fs
);
1707 ret
= fs_set_property(fd_fs
, "mode", "0620");
1709 return syserror("Failed to set \"mode=0620\" property on devpts filesystem context %d", fd_fs
);
1711 ret
= fs_set_property(fd_fs
, "max", fdstr(pty_max
));
1713 return syserror("Failed to set \"max=%zu\" property on devpts filesystem context %d", conf
->pty_max
, fd_fs
);
1715 ret
= fsconfig(fd_fs
, FSCONFIG_CMD_CREATE
, NULL
, NULL
, 0);
1717 return syserror("Failed to finalize filesystem context %d", fd_fs
);
1719 devpts_fd
= fsmount(fd_fs
, FSMOUNT_CLOEXEC
, MOUNT_ATTR_NOSUID
| MOUNT_ATTR_NOEXEC
);
1721 return syserror("Failed to create new mount for filesystem context %d", fd_fs
);
1722 TRACE("Created detached devpts mount %d", devpts_fd
);
1724 ret
= move_mount(devpts_fd
, "", rootfs
->dfd_dev
, "pts", MOVE_MOUNT_F_EMPTY_PATH
);
1726 return syserror("Failed to attach devpts mount %d to %d/pts", conf
->devpts_fd
, rootfs
->dfd_dev
);
1728 DEBUG("Attached detached devpts mount %d to %d/pts", devpts_fd
, rootfs
->dfd_dev
);
1731 char devpts_mntopts
[256];
1732 char *mntopt_sets
[5];
1733 char default_devpts_mntopts
[256] = "gid=5,newinstance,ptmxmode=0666,mode=0620";
1736 * Fallback codepath in case the new mount API can't be used to
1737 * create detached mounts.
1740 ret
= strnprintf(devpts_mntopts
, sizeof(devpts_mntopts
), "%s,max=%zu",
1741 default_devpts_mntopts
, pty_max
);
1745 /* Create mountpoint for devpts instance. */
1746 ret
= mkdirat(rootfs
->dfd_dev
, "pts", 0755);
1747 if (ret
< 0 && errno
!= EEXIST
)
1748 return log_error_errno(-1, errno
, "Failed to create \"/dev/pts\" directory");
1751 mntopt_sets
[0] = devpts_mntopts
;
1753 /* !gid=5 && max= */
1754 mntopt_sets
[1] = devpts_mntopts
+ STRLITERALLEN("gid=5") + 1;
1756 /* gid=5 && !max= */
1757 mntopt_sets
[2] = default_devpts_mntopts
;
1759 /* !gid=5 && !max= */
1760 mntopt_sets
[3] = default_devpts_mntopts
+ STRLITERALLEN("gid=5") + 1;
1763 mntopt_sets
[4] = NULL
;
1765 for (ret
= -1, opts
= mntopt_sets
; opts
&& *opts
; opts
++) {
1766 /* mount new devpts instance */
1767 ret
= mount_at(rootfs
->dfd_dev
, "", 0,
1768 rootfs
->dfd_dev
, "pts", PROTECT_LOOKUP_BENEATH
,
1769 "devpts", MS_NOSUID
| MS_NOEXEC
, *opts
);
1774 return log_error_errno(-1, errno
, "Failed to mount new devpts instance");
1776 devpts_fd
= open_at(rootfs
->dfd_dev
, "pts", PROTECT_OPATH_DIRECTORY
, PROTECT_LOOKUP_BENEATH_XDEV
, 0);
1777 if (devpts_fd
< 0) {
1779 TRACE("Failed to create detached devpts mount");
1782 DEBUG("Mounted new devpts instance with options \"%s\"", *opts
);
1785 handler
->conf
->devpts_fd
= move_fd(devpts_fd
);
1788 * In order to allocate terminal devices the devpts filesystem will
1789 * have to be attached to the filesystem at least ones in the new mount
1790 * api. The reason is lengthy but the gist is that until the new mount
1791 * has been attached to the filesystem it is a detached mount with an
1792 * anonymous mount mamespace attached to it for which the kernel
1793 * refuses certain operations.
1794 * We end up here if the user has requested to allocate tty devices
1795 * while not requestig pty devices be made available to the container.
1796 * We only need the devpts_fd to allocate tty devices.
1798 if (conf
->pty_max
<= 0)
1801 /* Remove any pre-existing /dev/ptmx file. */
1802 ret
= unlinkat(rootfs
->dfd_dev
, "ptmx", 0);
1804 if (errno
!= ENOENT
)
1805 return log_error_errno(-1, errno
, "Failed to remove existing \"/dev/ptmx\" file");
1807 DEBUG("Removed existing \"/dev/ptmx\" file");
1810 /* Create placeholder /dev/ptmx file as bind mountpoint for /dev/pts/ptmx. */
1811 ret
= mknodat(rootfs
->dfd_dev
, "ptmx", S_IFREG
| 0000, 0);
1812 if (ret
< 0 && errno
!= EEXIST
)
1813 return log_error_errno(-1, errno
, "Failed to create \"/dev/ptmx\" file as bind mount target");
1814 DEBUG("Created \"/dev/ptmx\" file as bind mount target");
1816 /* Main option: use a bind-mount to please AppArmor */
1817 ret
= mount_at(rootfs
->dfd_dev
, "pts/ptmx", (PROTECT_LOOKUP_BENEATH_WITH_SYMLINKS
& ~RESOLVE_NO_XDEV
),
1818 rootfs
->dfd_dev
, "ptmx", (PROTECT_LOOKUP_BENEATH_WITH_SYMLINKS
& ~RESOLVE_NO_XDEV
),
1819 NULL
, MS_BIND
, NULL
);
1821 return log_debug(0, "Bind mounted \"/dev/pts/ptmx\" to \"/dev/ptmx\"");
1823 /* Fallthrough and try to create a symlink. */
1824 ERROR("Failed to bind mount \"/dev/pts/ptmx\" to \"/dev/ptmx\"");
1826 /* Remove the placeholder /dev/ptmx file we created above. */
1827 ret
= unlinkat(rootfs
->dfd_dev
, "ptmx", 0);
1829 return log_error_errno(-1, errno
, "Failed to remove existing \"/dev/ptmx\"");
1831 /* Fallback option: Create symlink /dev/ptmx -> /dev/pts/ptmx. */
1832 ret
= symlinkat("/dev/pts/ptmx", rootfs
->dfd_dev
, "dev/ptmx");
1834 return log_error_errno(-1, errno
, "Failed to create symlink from \"/dev/ptmx\" to \"/dev/pts/ptmx\"");
1836 DEBUG("Created symlink from \"/dev/ptmx\" to \"/dev/pts/ptmx\"");
1840 static int lxc_finish_devpts_child(struct lxc_handler
*handler
)
1842 struct lxc_conf
*conf
= handler
->conf
;
1843 struct lxc_rootfs
*rootfs
= &conf
->rootfs
;
1846 if (conf
->pty_max
> 0)
1850 * We end up here if the user has requested to allocate tty devices
1851 * while not requestig pty devices be made available to the container.
1852 * This means we can unmount the devpts instance. We only need the
1853 * devpts_fd to allocate tty devices.
1855 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
),
1856 "/proc/self/fd/%d/pts", rootfs
->dfd_dev
);
1858 return syserror("Failed to create path");
1860 close_prot_errno_disarm(conf
->devpts_fd
);
1861 return umount2(rootfs
->buf
, MNT_DETACH
);
1864 static int lxc_send_devpts_to_parent(struct lxc_handler
*handler
)
1868 if (handler
->conf
->pty_max
<= 0)
1869 return log_debug(0, "No devpts file descriptor will be sent since no pts devices are requested");
1871 ret
= lxc_abstract_unix_send_fds(handler
->data_sock
[0], &handler
->conf
->devpts_fd
, 1, NULL
, 0);
1873 SYSERROR("Failed to send devpts file descriptor %d to parent", handler
->conf
->devpts_fd
);
1875 TRACE("Sent devpts file descriptor %d to parent", handler
->conf
->devpts_fd
);
1877 close_prot_errno_disarm(handler
->conf
->devpts_fd
);
1882 static int setup_personality(personality_t persona
)
1886 if (persona
== LXC_ARCH_UNCHANGED
)
1887 return log_debug(0, "Retaining original personality");
1889 ret
= lxc_personality(persona
);
1891 return syserror("Failed to set personality to \"0lx%lx\"", persona
);
1893 INFO("Set personality to \"0lx%lx\"", persona
);
1897 static int bind_mount_console(int fd_devpts
, struct lxc_rootfs
*rootfs
,
1898 struct lxc_terminal
*console
, int fd_to
)
1900 __do_close
int fd_pty
= -EBADF
;
1902 if (is_empty_string(console
->name
))
1903 return ret_errno(EINVAL
);
1906 * When the pty fd stashed in console->pty has been retrieved via the
1907 * TIOCGPTPEER ioctl() to avoid dangerous path-based lookups when
1908 * allocating new pty devices we can't reopen it through openat2() or
1909 * created a detached mount through open_tree() from it. This means we
1910 * would need to mount using the path stased in console->name which is
1911 * unsafe. We could be mounting a device that isn't identical to the
1912 * one we've already safely opened and stashed in console->pty.
1913 * So, what we do is we open an O_PATH file descriptor for
1914 * console->name and verify that the opened fd and the fd we stashed in
1915 * console->pty refer to the same device. If they do we can go on and
1916 * created a detached mount based on the newly opened O_PATH file
1917 * descriptor and then safely mount.
1919 fd_pty
= open_at_same(console
->pty
, fd_devpts
, fdstr(console
->pty_nr
),
1920 PROTECT_OPATH_FILE
, PROTECT_LOOKUP_ABSOLUTE_XDEV
, 0);
1922 return syserror("Failed to open \"%s\"", console
->name
);
1925 * Note, there are intentionally no open or lookup restrictions since
1926 * we're operating directly on the fd.
1928 if (can_use_mount_api())
1929 return fd_bind_mount(fd_pty
, "", 0, 0, fd_to
, "", 0, 0, 0, 0, 0, false);
1931 return mount_fd(fd_pty
, fd_to
, "none", MS_BIND
, 0);
1934 static int lxc_setup_dev_console(int fd_devpts
, struct lxc_rootfs
*rootfs
,
1935 struct lxc_terminal
*console
)
1937 __do_close
int fd_console
= -EBADF
;
1941 * When we are asked to setup a console we remove any previous
1942 * /dev/console bind-mounts.
1944 if (exists_file_at(rootfs
->dfd_dev
, "console")) {
1945 char *rootfs_path
= rootfs
->path
? rootfs
->mount
: "";
1947 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "%s/dev/console", rootfs_path
);
1951 ret
= lxc_unstack_mountpoint(rootfs
->buf
, false);
1953 return log_error_errno(-ret
, errno
, "Failed to unmount \"%s\"", rootfs
->buf
);
1955 DEBUG("Cleared all (%d) mounts from \"%s\"", ret
, rootfs
->buf
);
1959 * For unprivileged containers autodev or automounts will already have
1960 * taken care of creating /dev/console.
1962 fd_console
= open_at(rootfs
->dfd_dev
,
1964 PROTECT_OPEN
| O_CREAT
,
1965 PROTECT_LOOKUP_BENEATH
,
1968 return syserror("Failed to create \"%d/console\"", rootfs
->dfd_dev
);
1970 ret
= fchmod(console
->pty
, 0620);
1972 return syserror("Failed to change console mode");
1974 ret
= bind_mount_console(fd_devpts
, rootfs
, console
, fd_console
);
1976 return syserror("Failed to mount \"%d(%s)\" on \"%d\"",
1977 console
->pty
, console
->name
, fd_console
);
1979 TRACE("Setup console \"%s\"", console
->name
);
1983 static int lxc_setup_ttydir_console(int fd_devpts
, struct lxc_rootfs
*rootfs
,
1984 struct lxc_terminal
*console
,
1987 __do_close
int fd_ttydir
= -EBADF
, fd_dev_console
= -EBADF
,
1988 fd_reg_console
= -EBADF
, fd_reg_ttydir_console
= -EBADF
;
1991 /* create dev/<ttydir> */
1992 ret
= mkdirat(rootfs
->dfd_dev
, ttydir
, 0755);
1993 if (ret
< 0 && errno
!= EEXIST
)
1994 return syserror("Failed to create \"%d/%s\"", rootfs
->dfd_dev
, ttydir
);
1996 fd_ttydir
= open_at(rootfs
->dfd_dev
,
1998 PROTECT_OPATH_DIRECTORY
,
1999 PROTECT_LOOKUP_BENEATH
,
2002 return syserror("Failed to open \"%d/%s\"", rootfs
->dfd_dev
, ttydir
);
2004 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "%s/console", ttydir
);
2008 /* create dev/<ttydir>/console */
2009 fd_reg_ttydir_console
= open_at(fd_ttydir
,
2011 PROTECT_OPEN
| O_CREAT
,
2012 PROTECT_LOOKUP_BENEATH
,
2014 if (fd_reg_ttydir_console
< 0)
2015 return syserror("Failed to create \"%d/console\"", fd_ttydir
);
2017 if (file_exists(rootfs
->buf
)) {
2018 char *rootfs_path
= rootfs
->path
? rootfs
->mount
: "";
2020 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "%s/dev/console", rootfs_path
);
2024 ret
= lxc_unstack_mountpoint(rootfs
->buf
, false);
2026 return log_error_errno(-ret
, errno
, "Failed to unmount \"%s\"", rootfs
->buf
);
2028 DEBUG("Cleared all (%d) mounts from \"%s\"", ret
, rootfs
->buf
);
2031 /* create dev/console */
2032 fd_reg_console
= open_at(rootfs
->dfd_dev
,
2034 PROTECT_OPEN
| O_CREAT
,
2035 PROTECT_LOOKUP_BENEATH
,
2037 if (fd_reg_console
< 0)
2038 return syserror("Failed to create \"%d/console\"", rootfs
->dfd_dev
);
2040 ret
= fchmod(console
->pty
, 0620);
2042 return syserror("Failed to change console mode");
2044 /* bind mount console to '/dev/<ttydir>/console' */
2045 ret
= bind_mount_console(fd_devpts
, rootfs
, console
, fd_reg_ttydir_console
);
2047 return syserror("Failed to mount \"%d(%s)\" on \"%d\"",
2048 console
->pty
, console
->name
, fd_reg_ttydir_console
);
2050 fd_dev_console
= open_at_same(console
->pty
,
2054 PROTECT_LOOKUP_BENEATH_XDEV
,
2056 if (fd_dev_console
< 0)
2057 return syserror("Failed to open \"%d/console\"", fd_ttydir
);
2059 /* bind mount '/dev/<ttydir>/console' to '/dev/console' */
2060 if (can_use_mount_api())
2061 ret
= fd_bind_mount(fd_dev_console
,
2064 PROTECT_LOOKUP_BENEATH_XDEV
,
2068 PROTECT_LOOKUP_BENEATH
,
2074 ret
= mount_fd(fd_dev_console
, fd_reg_console
, "none", MS_BIND
, 0);
2076 return syserror("Failed to mount \"%d\" on \"%d\"",
2077 fd_dev_console
, fd_reg_console
);
2079 TRACE("Setup console \"%s\"", console
->name
);
2083 static int lxc_setup_console(const struct lxc_handler
*handler
,
2084 struct lxc_rootfs
*rootfs
,
2085 struct lxc_terminal
*console
, char *ttydir
)
2087 __do_close
int fd_devpts_host
= -EBADF
;
2088 int fd_devpts
= handler
->conf
->devpts_fd
;
2091 if (!wants_console(console
))
2092 return log_trace(0, "Skipping console setup");
2094 if (console
->pty
< 0) {
2096 * Allocate a console from the container's devpts instance. We
2097 * have checked on the host that we have enough pty devices
2100 ret
= lxc_devpts_terminal(handler
->conf
->devpts_fd
, &console
->ptx
,
2101 &console
->pty
, &console
->pty_nr
, false);
2103 return syserror("Failed to allocate console from container's devpts instance");
2105 ret
= strnprintf(console
->name
, sizeof(console
->name
),
2106 "/dev/pts/%d", console
->pty_nr
);
2108 return syserror("Failed to create console path");
2111 * We're using a console from the host's devpts instance. Open
2112 * it again so we can later verify that the console we're
2113 * supposed to use is still the same as the one we opened on
2116 fd_devpts_host
= open_at(rootfs
->dfd_host
,
2118 PROTECT_OPATH_DIRECTORY
,
2119 PROTECT_LOOKUP_BENEATH_XDEV
,
2121 if (fd_devpts_host
< 0)
2122 return syserror("Failed to open host devpts");
2124 fd_devpts
= fd_devpts_host
;
2128 ret
= lxc_setup_ttydir_console(fd_devpts
, rootfs
, console
, ttydir
);
2130 ret
= lxc_setup_dev_console(fd_devpts
, rootfs
, console
);
2132 return syserror("Failed to setup console");
2135 * Some init's such as busybox will set sane tty settings on stdin,
2136 * stdout, stderr which it thinks is the console. We already set them
2137 * the way we wanted on the real terminal, and we want init to do its
2138 * setup on its console ie. the pty allocated in lxc_terminal_setup() so
2139 * make sure that that pty is stdin,stdout,stderr.
2141 if (console
->pty
>= 0) {
2142 if (handler
->daemonize
|| !handler
->conf
->is_execute
)
2143 ret
= set_stdfds(console
->pty
);
2145 ret
= lxc_terminal_set_stdfds(console
->pty
);
2147 return syserror("Failed to redirect std{in,out,err} to pty file descriptor %d", console
->pty
);
2150 * If the console has been allocated from the host's devpts
2151 * we're done and we don't need to send fds to the parent.
2153 if (fd_devpts_host
>= 0)
2154 lxc_terminal_delete(console
);
2160 static int parse_mntopt(char *opt
, unsigned long *flags
, char **data
, size_t size
)
2164 /* If '=' is contained in opt, the option must go into data. */
2165 if (!strchr(opt
, '=')) {
2167 * If opt is found in mount_opt, set or clear flags.
2168 * Otherwise append it to data.
2170 size_t opt_len
= strlen(opt
);
2171 for (struct mount_opt
*mo
= &mount_opt
[0]; mo
->name
!= NULL
; mo
++) {
2172 size_t mo_name_len
= strlen(mo
->name
);
2174 if (opt_len
== mo_name_len
&& strnequal(opt
, mo
->name
, mo_name_len
)) {
2176 *flags
&= ~mo
->legacy_flag
;
2178 *flags
|= mo
->legacy_flag
;
2184 if (strlen(*data
)) {
2185 ret
= strlcat(*data
, ",", size
);
2187 return log_error_errno(ret
, errno
, "Failed to append \",\" to %s", *data
);
2190 ret
= strlcat(*data
, opt
, size
);
2192 return log_error_errno(ret
, errno
, "Failed to append \"%s\" to %s", opt
, *data
);
2197 int parse_mntopts_legacy(const char *mntopts
, unsigned long *mntflags
, char **mntdata
)
2199 __do_free
char *mntopts_new
= NULL
, *mntopts_dup
= NULL
;
2200 char *mntopt_cur
= NULL
;
2203 if (*mntdata
|| *mntflags
)
2204 return ret_errno(EINVAL
);
2209 mntopts_dup
= strdup(mntopts
);
2211 return ret_errno(ENOMEM
);
2213 size
= strlen(mntopts_dup
) + 1;
2214 mntopts_new
= zalloc(size
);
2216 return ret_errno(ENOMEM
);
2218 lxc_iterate_parts(mntopt_cur
, mntopts_dup
, ",")
2219 if (parse_mntopt(mntopt_cur
, mntflags
, &mntopts_new
, size
) < 0)
2220 return ret_errno(EINVAL
);
2223 *mntdata
= move_ptr(mntopts_new
);
2228 static int parse_vfs_attr(struct lxc_mount_options
*opts
, char *opt
, size_t size
)
2231 * If opt is found in mount_opt, set or clear flags.
2232 * Otherwise append it to data.
2234 for (struct mount_opt
*mo
= &mount_opt
[0]; mo
->name
!= NULL
; mo
++) {
2235 if (!strnequal(opt
, mo
->name
, strlen(mo
->name
)))
2238 /* This is a recursive bind-mount. */
2239 if (strequal(mo
->name
, "rbind")) {
2240 opts
->bind_recursively
= 1;
2242 opts
->mnt_flags
|= mo
->legacy_flag
; /* MS_BIND | MS_REC */
2246 /* This is a bind-mount. */
2247 if (strequal(mo
->name
, "bind")) {
2249 opts
->mnt_flags
|= mo
->legacy_flag
; /* MS_BIND */
2254 return log_info(0, "Ignoring %s mount option", mo
->name
);
2257 opts
->attr
.attr_clr
|= mo
->flag
;
2258 opts
->mnt_flags
&= ~mo
->legacy_flag
;
2259 TRACE("Lowering %s", mo
->name
);
2261 opts
->attr
.attr_set
|= mo
->flag
;
2262 opts
->mnt_flags
|= mo
->legacy_flag
;
2263 TRACE("Raising %s", mo
->name
);
2269 for (struct mount_opt
*mo
= &propagation_opt
[0]; mo
->name
!= NULL
; mo
++) {
2270 if (!strnequal(opt
, mo
->name
, strlen(mo
->name
)))
2273 if (strequal(mo
->name
, "rslave") ||
2274 strequal(mo
->name
, "rshared") ||
2275 strequal(mo
->name
, "runbindable") ||
2276 strequal(mo
->name
, "rprivate"))
2277 opts
->propagate_recursively
= 1;
2279 opts
->attr
.propagation
= mo
->flag
;
2280 opts
->prop_flags
|= mo
->legacy_flag
;
2287 int parse_mount_attrs(struct lxc_mount_options
*opts
, const char *mntopts
)
2289 __do_free
char *mntopts_new
= NULL
, *mntopts_dup
= NULL
;
2290 char *end
= NULL
, *mntopt_cur
= NULL
;
2295 return ret_errno(EINVAL
);
2300 mntopts_dup
= strdup(mntopts
);
2302 return ret_errno(ENOMEM
);
2304 size
= strlen(mntopts_dup
) + 1;
2305 mntopts_new
= zalloc(size
);
2307 return ret_errno(ENOMEM
);
2309 lxc_iterate_parts(mntopt_cur
, mntopts_dup
, ",") {
2310 /* This is a filesystem specific option. */
2311 if (strchr(mntopt_cur
, '=')) {
2313 end
= stpcpy(mntopts_new
, mntopt_cur
);
2315 end
= stpcpy(end
, ",");
2316 end
= stpcpy(end
, mntopt_cur
);
2322 /* This is a generic vfs option. */
2323 ret
= parse_vfs_attr(opts
, mntopt_cur
, size
);
2325 return syserror("Failed to parse mount attributes: \"%s\"", mntopt_cur
);
2329 opts
->data
= move_ptr(mntopts_new
);
2334 static void null_endofword(char *word
)
2336 while (*word
&& *word
!= ' ' && *word
!= '\t')
2341 /* skip @nfields spaces in @src */
2342 static char *get_field(char *src
, int nfields
)
2347 for (i
= 0; i
< nfields
; i
++) {
2348 while (*p
&& *p
!= ' ' && *p
!= '\t')
2360 static int mount_entry(const char *fsname
, const char *target
,
2361 const char *fstype
, unsigned long mountflags
,
2362 unsigned long pflags
, const char *data
, bool optional
,
2363 bool dev
, bool relative
, const char *rootfs
)
2366 char srcbuf
[PATH_MAX
];
2367 const char *srcpath
= fsname
;
2373 ret
= strnprintf(srcbuf
, sizeof(srcbuf
), "%s/%s", rootfs
? rootfs
: "/", fsname
? fsname
: "");
2375 return log_error_errno(-1, errno
, "source path is too long");
2379 ret
= safe_mount(srcpath
, target
, fstype
, mountflags
& ~MS_REMOUNT
, data
,
2383 return log_info_errno(0, errno
, "Failed to mount \"%s\" on \"%s\" (optional)",
2384 srcpath
? srcpath
: "(null)", target
);
2386 return log_error_errno(-1, errno
, "Failed to mount \"%s\" on \"%s\"",
2387 srcpath
? srcpath
: "(null)", target
);
2390 if ((mountflags
& MS_REMOUNT
) || (mountflags
& MS_BIND
)) {
2392 DEBUG("Remounting \"%s\" on \"%s\" to respect bind or remount options",
2393 srcpath
? srcpath
: "(none)", target
? target
: "(none)");
2396 if (srcpath
&& statvfs(srcpath
, &sb
) == 0) {
2397 unsigned long required_flags
= 0;
2399 if (sb
.f_flag
& MS_NOSUID
)
2400 required_flags
|= MS_NOSUID
;
2402 if (sb
.f_flag
& MS_NODEV
&& !dev
)
2403 required_flags
|= MS_NODEV
;
2405 if (sb
.f_flag
& MS_RDONLY
)
2406 required_flags
|= MS_RDONLY
;
2408 if (sb
.f_flag
& MS_NOEXEC
)
2409 required_flags
|= MS_NOEXEC
;
2411 DEBUG("Flags for \"%s\" were %lu, required extra flags are %lu",
2412 srcpath
, sb
.f_flag
, required_flags
);
2414 /* If this was a bind mount request, and required_flags
2415 * does not have any flags which are not already in
2416 * mountflags, then skip the remount.
2418 if (!(mountflags
& MS_REMOUNT
) &&
2419 (!(required_flags
& ~mountflags
) && !(mountflags
& MS_RDONLY
))) {
2420 DEBUG("Mountflags already were %lu, skipping remount", mountflags
);
2424 mountflags
|= required_flags
;
2428 ret
= mount(srcpath
, target
, fstype
, mountflags
| MS_REMOUNT
, data
);
2431 return log_info_errno(0, errno
, "Failed to mount \"%s\" on \"%s\" (optional)",
2432 srcpath
? srcpath
: "(null)",
2435 return log_error_errno(-1, errno
, "Failed to mount \"%s\" on \"%s\"",
2436 srcpath
? srcpath
: "(null)",
2445 ret
= mount(NULL
, target
, NULL
, pflags
, NULL
);
2448 return log_info_errno(0, errno
, "Failed to change mount propagation for \"%s\" (optional)", target
);
2450 return log_error_errno(-1, errno
, "Failed to change mount propagation for \"%s\" (optional)", target
);
2452 DEBUG("Changed mount propagation for \"%s\"", target
);
2455 DEBUG("Mounted \"%s\" on \"%s\" with filesystem type \"%s\"",
2456 srcpath
? srcpath
: "(null)", target
, fstype
);
2461 const char *lxc_mount_options_info
[LXC_MOUNT_MAX
] = {
2469 /* Remove "optional", "create=dir", and "create=file" from mntopt */
2470 int parse_lxc_mount_attrs(struct lxc_mount_options
*opts
, char *mnt_opts
)
2472 for (size_t i
= LXC_MOUNT_CREATE_DIR
; i
< LXC_MOUNT_MAX
; i
++) {
2473 __do_close
int fd_userns
= -EBADF
;
2474 const char *opt_name
= lxc_mount_options_info
[i
];
2476 char *idmap_path
, *opt
, *opt_next
;
2478 opt
= strstr(mnt_opts
, opt_name
);
2483 case LXC_MOUNT_CREATE_DIR
:
2484 opts
->create_dir
= 1;
2486 case LXC_MOUNT_CREATE_FILE
:
2487 opts
->create_file
= 1;
2489 case LXC_MOUNT_OPTIONAL
:
2492 case LXC_MOUNT_RELATIVE
:
2495 case LXC_MOUNT_IDMAP
:
2497 opt_next
+= STRLITERALLEN("idmap=");
2498 idmap_path
= strchrnul(opt_next
, ',');
2499 len
= idmap_path
- opt_next
+ 1;
2501 if (len
>= sizeof(opts
->userns_path
))
2502 return syserror_set(-EIO
, "Excessive idmap path length for \"idmap=<path>\" LXC specific mount option");
2504 strlcpy(opts
->userns_path
, opt_next
, len
);
2506 if (is_empty_string(opts
->userns_path
))
2507 return syserror_set(-EINVAL
, "Missing idmap path for \"idmap=<path>\" LXC specific mount option");
2509 if (!strequal(opts
->userns_path
, "container")) {
2510 fd_userns
= open(opts
->userns_path
, O_RDONLY
| O_NOCTTY
| O_CLOEXEC
);
2512 return syserror("Failed to open user namespace %s", opts
->userns_path
);
2515 TRACE("Parse LXC specific mount option %d->\"idmap=%s\"", fd_userns
, opts
->userns_path
);
2518 return syserror_set(-EINVAL
, "Unknown LXC specific mount option");
2521 opt_next
= strchr(opt
, ',');
2523 *opt
= '\0'; /* no more mntopts, so just chop it here */
2525 memmove(opt
, opt_next
+ 1, strlen(opt_next
+ 1) + 1);
2531 static int mount_entry_create_dir_file(const struct mntent
*mntent
,
2533 const struct lxc_rootfs
*rootfs
,
2534 const char *lxc_name
, const char *lxc_path
)
2536 __do_free
char *p1
= NULL
;
2540 if (strnequal(mntent
->mnt_type
, "overlay", 7)) {
2541 ret
= ovl_mkdir(mntent
, rootfs
, lxc_name
, lxc_path
);
2546 if (hasmntopt(mntent
, "create=dir")) {
2547 ret
= mkdir_p(path
, 0755);
2548 if (ret
< 0 && errno
!= EEXIST
)
2549 return log_error_errno(-1, errno
, "Failed to create directory \"%s\"", path
);
2552 if (!hasmntopt(mntent
, "create=file"))
2555 ret
= access(path
, F_OK
);
2565 ret
= mkdir_p(p2
, 0755);
2566 if (ret
< 0 && errno
!= EEXIST
)
2567 return log_error_errno(-1, errno
, "Failed to create directory \"%s\"", path
);
2569 ret
= mknod(path
, S_IFREG
| 0000, 0);
2570 if (ret
< 0 && errno
!= EEXIST
)
2576 /* rootfs, lxc_name, and lxc_path can be NULL when the container is created
2577 * without a rootfs. */
2578 static inline int mount_entry_on_generic(struct mntent
*mntent
,
2580 const struct lxc_rootfs
*rootfs
,
2581 const char *lxc_name
,
2582 const char *lxc_path
)
2584 __do_free
char *mntdata
= NULL
;
2585 char *rootfs_path
= NULL
;
2587 bool dev
, optional
, relative
;
2588 struct lxc_mount_options opts
= {};
2590 optional
= hasmntopt(mntent
, "optional") != NULL
;
2591 dev
= hasmntopt(mntent
, "dev") != NULL
;
2592 relative
= hasmntopt(mntent
, "relative") != NULL
;
2594 if (rootfs
&& rootfs
->path
)
2595 rootfs_path
= rootfs
->mount
;
2597 ret
= mount_entry_create_dir_file(mntent
, path
, rootfs
, lxc_name
,
2606 ret
= parse_lxc_mount_attrs(&opts
, mntent
->mnt_opts
);
2611 * Idmapped mount entries will be setup by the parent for us. Note that
2612 * we rely on mount_entry_create_dir_file() above to have already
2613 * created the target path for us. So the parent can just open the
2614 * target and send us the target fd.
2617 if (!is_empty_string(opts
.userns_path
))
2618 return systrace_ret(0, "Skipping idmapped mount entry");
2620 ret
= parse_mount_attrs(&opts
, mntent
->mnt_opts
);
2624 ret
= mount_entry(mntent
->mnt_fsname
,
2638 static inline int mount_entry_on_systemfs(struct lxc_rootfs
*rootfs
,
2639 struct mntent
*mntent
)
2643 /* For containers created without a rootfs all mounts are treated as
2644 * absolute paths starting at / on the host.
2646 if (mntent
->mnt_dir
[0] != '/')
2647 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "/%s", mntent
->mnt_dir
);
2649 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "%s", mntent
->mnt_dir
);
2653 return mount_entry_on_generic(mntent
, rootfs
->buf
, NULL
, NULL
, NULL
);
2656 static int mount_entry_on_absolute_rootfs(struct mntent
*mntent
,
2657 struct lxc_rootfs
*rootfs
,
2658 const char *lxc_name
,
2659 const char *lxc_path
)
2663 const char *lxcpath
;
2666 lxcpath
= lxc_global_config_value("lxc.lxcpath");
2670 /* If rootfs->path is a blockdev path, allow container fstab to use
2671 * <lxcpath>/<name>/rootfs" as the target prefix.
2673 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "%s/%s/rootfs", lxcpath
, lxc_name
);
2677 aux
= strstr(mntent
->mnt_dir
, rootfs
->buf
);
2679 offset
= strlen(rootfs
->buf
);
2684 aux
= strstr(mntent
->mnt_dir
, rootfs
->path
);
2686 return log_warn(ret
, "Ignoring mount point \"%s\"", mntent
->mnt_dir
);
2687 offset
= strlen(rootfs
->path
);
2690 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "%s/%s", rootfs
->mount
, aux
+ offset
);
2694 return mount_entry_on_generic(mntent
, rootfs
->buf
, rootfs
, lxc_name
, lxc_path
);
2697 static int mount_entry_on_relative_rootfs(struct mntent
*mntent
,
2698 struct lxc_rootfs
*rootfs
,
2699 const char *lxc_name
,
2700 const char *lxc_path
)
2704 /* relative to root mount point */
2705 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "%s/%s", rootfs
->mount
, mntent
->mnt_dir
);
2709 return mount_entry_on_generic(mntent
, rootfs
->buf
, rootfs
, lxc_name
, lxc_path
);
2712 static int mount_file_entries(struct lxc_rootfs
*rootfs
, FILE *file
,
2713 const char *lxc_name
, const char *lxc_path
)
2716 struct mntent mntent
;
2718 while (getmntent_r(file
, &mntent
, buf
, sizeof(buf
))) {
2722 ret
= mount_entry_on_systemfs(rootfs
, &mntent
);
2723 else if (mntent
.mnt_dir
[0] != '/')
2724 ret
= mount_entry_on_relative_rootfs(&mntent
, rootfs
,
2725 lxc_name
, lxc_path
);
2727 ret
= mount_entry_on_absolute_rootfs(&mntent
, rootfs
,
2728 lxc_name
, lxc_path
);
2733 if (!feof(file
) || ferror(file
))
2734 return log_error(-1, "Failed to parse mount entries");
2739 static inline void __auto_endmntent__(FILE **f
)
2745 #define __do_endmntent __attribute__((__cleanup__(__auto_endmntent__)))
2747 static int setup_mount_fstab(struct lxc_rootfs
*rootfs
, const char *fstab
,
2748 const char *lxc_name
, const char *lxc_path
)
2750 __do_endmntent
FILE *f
= NULL
;
2756 f
= setmntent(fstab
, "re");
2758 return log_error_errno(-1, errno
, "Failed to open \"%s\"", fstab
);
2760 ret
= mount_file_entries(rootfs
, f
, lxc_name
, lxc_path
);
2762 ERROR("Failed to set up mount entries");
2768 * In order for nested containers to be able to mount /proc and /sys they need
2769 * to see a "pure" proc and sysfs mount points with nothing mounted on top
2771 * For this we provide proc and sysfs in /dev/.lxc/{proc,sys} while using an
2772 * apparmor rule to deny access to them. This is mostly for convenience: The
2773 * container's root user can mount them anyway and thus has access to the two
2774 * file systems. But a non-root user in the container should not be allowed to
2775 * access them as a side effect without explicitly allowing it.
2777 static const char nesting_helpers
[] =
2778 "proc dev/.lxc/proc proc create=dir,optional 0 0\n"
2779 "sys dev/.lxc/sys sysfs create=dir,optional 0 0\n";
2781 FILE *make_anonymous_mount_file(struct lxc_list
*mount
,
2782 bool include_nesting_helpers
)
2784 __do_close
int fd
= -EBADF
;
2788 struct lxc_list
*iterator
;
2790 fd
= memfd_create(".lxc_mount_file", MFD_CLOEXEC
);
2792 char template[] = P_tmpdir
"/.lxc_mount_file_XXXXXX";
2794 if (errno
!= ENOSYS
)
2797 fd
= lxc_make_tmpfile(template, true);
2799 return log_error_errno(NULL
, errno
, "Could not create temporary mount file");
2801 TRACE("Created temporary mount file");
2804 lxc_list_for_each (iterator
, mount
) {
2807 mount_entry
= iterator
->elem
;
2808 len
= strlen(mount_entry
);
2810 ret
= lxc_write_nointr(fd
, mount_entry
, len
);
2814 ret
= lxc_write_nointr(fd
, "\n", 1);
2819 if (include_nesting_helpers
) {
2820 ret
= lxc_write_nointr(fd
, nesting_helpers
,
2821 STRARRAYLEN(nesting_helpers
));
2822 if (ret
!= STRARRAYLEN(nesting_helpers
))
2826 ret
= lseek(fd
, 0, SEEK_SET
);
2830 f
= fdopen(fd
, "re+");
2832 move_fd(fd
); /* Transfer ownership of fd. */
2836 static int setup_mount_entries(const struct lxc_conf
*conf
,
2837 struct lxc_rootfs
*rootfs
, struct lxc_list
*mount
,
2838 const char *lxc_name
, const char *lxc_path
)
2840 __do_fclose
FILE *f
= NULL
;
2842 f
= make_anonymous_mount_file(mount
, conf
->lsm_aa_allow_nesting
);
2846 return mount_file_entries(rootfs
, f
, lxc_name
, lxc_path
);
2849 static int __lxc_idmapped_mounts_child(struct lxc_handler
*handler
, FILE *f
)
2851 struct lxc_conf
*conf
= handler
->conf
;
2852 struct lxc_rootfs
*rootfs
= &conf
->rootfs
;
2856 struct mntent mntent
;
2858 while (getmntent_r(f
, &mntent
, buf
, sizeof(buf
))) {
2859 __do_close
int fd_from
= -EBADF
, fd_to
= -EBADF
,
2861 __do_free
char *__data
= NULL
;
2862 int cur_mnt_seq
= -1;
2863 struct lxc_mount_options opts
= {};
2865 const char *source_relative
, *target_relative
;
2866 struct lxc_mount_attr attr
= {};
2868 ret
= parse_lxc_mount_attrs(&opts
, mntent
.mnt_opts
);
2870 return syserror("Failed to parse LXC specific mount options");
2873 ret
= parse_mount_attrs(&opts
, mntent
.mnt_opts
);
2875 return syserror("Failed to parse mount options");
2877 /* No idmapped mount entry so skip it. */
2878 if (is_empty_string(opts
.userns_path
))
2881 if (!can_use_bind_mounts())
2882 return syserror_set(-EINVAL
, "Kernel does not support idmapped mounts");
2885 return syserror_set(-EINVAL
, "Only bind mounts can currently be idmapped");
2887 /* We don't support new filesystem mounts yet. */
2888 if (!is_empty_string(mntent
.mnt_type
) &&
2889 !strequal(mntent
.mnt_type
, "none"))
2890 return syserror_set(-EINVAL
, "Only bind mounts can currently be idmapped");
2892 /* Someone specified additional mount options for a bind-mount. */
2893 if (!is_empty_string(opts
.data
))
2894 return syserror_set(-EINVAL
, "Bind mounts don't support non-generic mount options");
2897 * The source path is supposed to be taken relative to the
2898 * container's rootfs mount or - if the container does not have
2899 * a separate rootfs - to the host's /.
2901 source_relative
= deabs(mntent
.mnt_fsname
);
2902 if (opts
.relative
|| !rootfs
->path
)
2903 dfd_from
= rootfs
->dfd_mnt
;
2905 dfd_from
= rootfs
->dfd_host
;
2906 fd_from
= open_tree(dfd_from
, source_relative
,
2907 OPEN_TREE_CLONE
| OPEN_TREE_CLOEXEC
|
2908 (opts
.bind_recursively
? AT_RECURSIVE
: 0));
2910 return syserror("Failed to create detached %smount of %d/%s",
2911 opts
.bind_recursively
? "recursive " : "",
2912 dfd_from
, source_relative
);
2914 if (strequal(opts
.userns_path
, "container"))
2915 fd_userns
= openat(dfd_from
, "proc/self/ns/user", O_RDONLY
| O_CLOEXEC
);
2917 fd_userns
= open_at(-EBADF
, opts
.userns_path
,
2918 PROTECT_OPEN_WITH_TRAILING_SYMLINKS
, 0, 0);
2919 if (fd_userns
< 0) {
2920 if (opts
.optional
) {
2921 TRACE("Skipping optional idmapped mount");
2925 return syserror("Failed to open user namespace \"%s\" for detached %smount of %d/%s",
2926 opts
.userns_path
, opts
.bind_recursively
? "recursive " : "",
2927 dfd_from
, source_relative
);
2930 ret
= __lxc_abstract_unix_send_two_fds(handler
->data_sock
[0],
2932 &opts
, sizeof(opts
));
2934 if (opts
.optional
) {
2935 TRACE("Skipping optional idmapped mount");
2939 return syserror("Failed to send file descriptor %d for detached %smount of %d/%s and file descriptor %d of user namespace \"%s\" to parent",
2940 fd_from
, opts
.bind_recursively
? "recursive " : "",
2941 dfd_from
, source_relative
, fd_userns
,
2945 ret
= lxc_abstract_unix_rcv_credential(handler
->data_sock
[0],
2947 sizeof(cur_mnt_seq
));
2949 if (opts
.optional
) {
2950 TRACE("Skipping optional idmapped mount");
2954 return syserror("Failed to receive notification that parent idmapped detached %smount %d/%s to user namespace %d",
2955 opts
.bind_recursively
? "recursive " : "",
2956 dfd_from
, source_relative
, fd_userns
);
2959 if (mnt_seq
!= cur_mnt_seq
)
2960 return syserror("Expected mount sequence number and mount sequence number from parent mismatch: %d != %d",
2961 mnt_seq
, cur_mnt_seq
);
2964 /* Set regular mount options. */
2966 attr
.propagation
= 0;
2967 ret
= mount_setattr(fd_from
,
2970 (opts
.bind_recursively
? AT_RECURSIVE
: 0),
2974 if (opts
.optional
) {
2975 TRACE("Skipping optional idmapped mount");
2979 return syserror("Failed to set %smount options on detached %d/%s",
2980 opts
.bind_recursively
? "recursive " : "",
2981 dfd_from
, source_relative
);
2984 /* Set propagation mount options. */
2985 if (opts
.attr
.propagation
) {
2986 attr
= (struct lxc_mount_attr
) {
2987 attr
.propagation
= opts
.attr
.propagation
,
2990 ret
= mount_setattr(fd_from
,
2993 (opts
.propagate_recursively
? AT_RECURSIVE
: 0),
2997 if (opts
.optional
) {
2998 TRACE("Skipping optional idmapped mount");
3002 return syserror("Failed to set %spropagation mount options on detached %d/%s",
3003 opts
.bind_recursively
? "recursive " : "",
3004 dfd_from
, source_relative
);
3010 * In contrast to the legacy mount codepath we will simplify
3011 * our lifes and just always treat the target mountpoint to be
3012 * relative to the container's rootfs mountpoint or - if the
3013 * container does not have a separate rootfs - to the host's /.
3016 target_relative
= deabs(mntent
.mnt_dir
);
3018 dfd_from
= rootfs
->dfd_mnt
;
3020 dfd_from
= rootfs
->dfd_host
;
3021 fd_to
= open_at(dfd_from
, target_relative
, PROTECT_OPATH_FILE
, PROTECT_LOOKUP_BENEATH_WITH_SYMLINKS
, 0);
3023 if (opts
.optional
) {
3024 TRACE("Skipping optional idmapped mount");
3028 return syserror("Failed to open target mountpoint %d/%s for detached idmapped %smount %d:%d/%s",
3029 dfd_from
, target_relative
,
3030 opts
.bind_recursively
? "recursive " : "",
3031 fd_userns
, dfd_from
, source_relative
);
3034 ret
= move_detached_mount(fd_from
, fd_to
, "", 0, 0);
3036 if (opts
.optional
) {
3037 TRACE("Skipping optional idmapped mount");
3041 return syserror("Failed to attach detached idmapped %smount %d:%d/%s to target mountpoint %d/%s",
3042 opts
.bind_recursively
? "recursive " : "",
3043 fd_userns
, dfd_from
, source_relative
, dfd_from
, target_relative
);
3046 TRACE("Attached detached idmapped %smount %d:%d/%s to target mountpoint %d/%s",
3047 opts
.bind_recursively
? "recursive " : "", fd_userns
, dfd_from
,
3048 source_relative
, dfd_from
, target_relative
);
3051 if (!feof(f
) || ferror(f
))
3052 return syserror_set(-EINVAL
, "Failed to parse mount entries");
3057 static int lxc_idmapped_mounts_child(struct lxc_handler
*handler
)
3059 __do_fclose
FILE *f_entries
= NULL
;
3061 struct lxc_conf
*conf
= handler
->conf
;
3062 const char *fstab
= conf
->fstab
;
3063 struct lxc_list
*mount
= &conf
->mount_list
;
3066 f_entries
= make_anonymous_mount_file(mount
, conf
->lsm_aa_allow_nesting
);
3068 SYSERROR("Failed to create anonymous mount file");
3072 ret
= __lxc_idmapped_mounts_child(handler
, f_entries
);
3074 SYSERROR("Failed to setup idmapped mount entries");
3078 TRACE("Finished setting up idmapped mounts");
3081 __do_endmntent
FILE *f_fstab
= NULL
;
3083 f_fstab
= setmntent(fstab
, "re");
3085 SYSERROR("Failed to open fstab format file \"%s\"", fstab
);
3089 ret
= __lxc_idmapped_mounts_child(handler
, f_fstab
);
3091 SYSERROR("Failed to setup idmapped mount entries specified in fstab");
3095 TRACE("Finished setting up idmapped mounts specified in fstab");
3101 ret
= lxc_abstract_unix_send_credential(handler
->data_sock
[0], NULL
, 0);
3103 return syserror("Failed to inform parent that we are done setting up mounts");
3108 static int parse_cap(const char *cap
)
3112 size_t end
= sizeof(caps_opt
) / sizeof(caps_opt
[0]);
3115 if (strequal(cap
, "none"))
3118 for (i
= 0; i
< end
; i
++) {
3119 if (!strequal(cap
, caps_opt
[i
].name
))
3122 capid
= caps_opt
[i
].value
;
3127 /* Try to see if it's numeric, so the user may specify
3128 * capabilities that the running kernel knows about but we
3132 capid
= strtol(cap
, &ptr
, 10);
3133 if (!ptr
|| *ptr
!= '\0' || errno
!= 0)
3134 /* not a valid number */
3136 else if (capid
> lxc_caps_last_cap())
3137 /* we have a number but it's not a valid
3145 int in_caplist(int cap
, struct lxc_list
*caps
)
3148 struct lxc_list
*iterator
;
3150 lxc_list_for_each (iterator
, caps
) {
3151 capid
= parse_cap(iterator
->elem
);
3159 static int setup_caps(struct lxc_list
*caps
)
3163 struct lxc_list
*iterator
;
3165 lxc_list_for_each (iterator
, caps
) {
3168 drop_entry
= iterator
->elem
;
3170 capid
= parse_cap(drop_entry
);
3172 return log_error(-1, "unknown capability %s", drop_entry
);
3174 ret
= prctl(PR_CAPBSET_DROP
, prctl_arg(capid
), prctl_arg(0),
3175 prctl_arg(0), prctl_arg(0));
3177 return log_error_errno(-1, errno
, "Failed to remove %s capability", drop_entry
);
3178 DEBUG("Dropped %s (%d) capability", drop_entry
, capid
);
3181 DEBUG("Capabilities have been setup");
3185 static int dropcaps_except(struct lxc_list
*caps
)
3187 __do_free
int *caplist
= NULL
;
3188 int i
, capid
, numcaps
;
3190 struct lxc_list
*iterator
;
3192 numcaps
= lxc_caps_last_cap() + 1;
3193 if (numcaps
<= 0 || numcaps
> 200)
3195 TRACE("Found %d capabilities", numcaps
);
3197 /* caplist[i] is 1 if we keep capability i */
3198 caplist
= must_realloc(NULL
, numcaps
* sizeof(int));
3199 memset(caplist
, 0, numcaps
* sizeof(int));
3201 lxc_list_for_each (iterator
, caps
) {
3202 keep_entry
= iterator
->elem
;
3204 capid
= parse_cap(keep_entry
);
3209 return log_error(-1, "Unknown capability %s", keep_entry
);
3211 DEBUG("Keep capability %s (%d)", keep_entry
, capid
);
3215 for (i
= 0; i
< numcaps
; i
++) {
3221 ret
= prctl(PR_CAPBSET_DROP
, prctl_arg(i
), prctl_arg(0),
3222 prctl_arg(0), prctl_arg(0));
3224 return log_error_errno(-1, errno
, "Failed to remove capability %d", i
);
3227 DEBUG("Capabilities have been setup");
3231 static int parse_resource(const char *res
)
3237 for (i
= 0; i
< sizeof(limit_opt
) / sizeof(limit_opt
[0]); ++i
)
3238 if (strequal(res
, limit_opt
[i
].name
))
3239 return limit_opt
[i
].value
;
3241 /* Try to see if it's numeric, so the user may specify
3242 * resources that the running kernel knows about but
3245 ret
= lxc_safe_int(res
, &resid
);
3252 int setup_resource_limits(struct lxc_conf
*conf
, pid_t pid
)
3255 struct lxc_limit
*lim
;
3257 if (list_empty(&conf
->limits
))
3260 list_for_each_entry(lim
, &conf
->limits
, head
) {
3261 resid
= parse_resource(lim
->resource
);
3263 return log_error(-1, "Unknown resource %s", lim
->resource
);
3265 #if HAVE_PRLIMIT || HAVE_PRLIMIT64
3266 if (prlimit(pid
, resid
, &lim
->limit
, NULL
) != 0)
3267 return log_error_errno(-1, errno
, "Failed to set limit %s", lim
->resource
);
3269 TRACE("Setup \"%s\" limit", lim
->resource
);
3271 return log_error(-1, "Cannot set limit \"%s\" as prlimit is missing", lim
->resource
);
3275 TRACE("Setup resource limits");
3279 int setup_sysctl_parameters(struct lxc_conf
*conf
)
3281 __do_free
char *tmp
= NULL
;
3283 char filename
[PATH_MAX
] = {0};
3284 struct lxc_sysctl
*sysctl
, *nsysctl
;
3286 if (!list_empty(&conf
->sysctls
))
3289 list_for_each_entry_safe(sysctl
, nsysctl
, &conf
->sysctls
, head
) {
3290 tmp
= lxc_string_replace(".", "/", sysctl
->key
);
3292 return log_error(-1, "Failed to replace key %s", sysctl
->key
);
3294 ret
= strnprintf(filename
, sizeof(filename
), "/proc/sys/%s", tmp
);
3296 return log_error(-1, "Error setting up sysctl parameters path");
3298 ret
= lxc_write_to_file(filename
, sysctl
->value
,
3299 strlen(sysctl
->value
), false, 0666);
3301 return log_error_errno(-1, errno
, "Failed to setup sysctl parameters %s to %s",
3302 sysctl
->key
, sysctl
->value
);
3308 int setup_proc_filesystem(struct lxc_conf
*conf
, pid_t pid
)
3310 __do_free
char *tmp
= NULL
;
3312 char filename
[PATH_MAX
] = {0};
3313 struct lxc_proc
*proc
;
3315 if (!list_empty(&conf
->procs
))
3318 list_for_each_entry(proc
, &conf
->procs
, head
) {
3319 tmp
= lxc_string_replace(".", "/", proc
->filename
);
3321 return log_error(-1, "Failed to replace key %s", proc
->filename
);
3323 ret
= strnprintf(filename
, sizeof(filename
), "/proc/%d/%s", pid
, tmp
);
3325 return log_error(-1, "Error setting up proc filesystem path");
3327 ret
= lxc_write_to_file(filename
, proc
->value
,
3328 strlen(proc
->value
), false, 0666);
3330 return log_error_errno(-1, errno
, "Failed to setup proc filesystem %s to %s",
3331 proc
->filename
, proc
->value
);
3334 TRACE("Setup /proc/%d settings", pid
);
3338 static char *default_rootfs_mount
= LXCROOTFSMOUNT
;
3340 struct lxc_conf
*lxc_conf_init(void)
3343 struct lxc_conf
*new;
3345 new = zalloc(sizeof(*new));
3349 new->loglevel
= LXC_LOG_LEVEL_NOTSET
;
3350 new->personality
= LXC_ARCH_UNCHANGED
;
3352 new->console
.buffer_size
= 0;
3353 new->console
.log_path
= NULL
;
3354 new->console
.log_fd
= -1;
3355 new->console
.log_size
= 0;
3356 new->console
.path
= NULL
;
3357 new->console
.peer
= -1;
3358 new->console
.proxy
.busy
= -1;
3359 new->console
.proxy
.ptx
= -1;
3360 new->console
.proxy
.pty
= -1;
3361 new->console
.ptx
= -EBADF
;
3362 new->console
.pty
= -EBADF
;
3363 new->console
.pty_nr
= -1;
3364 new->console
.name
[0] = '\0';
3365 new->devpts_fd
= -EBADF
;
3366 memset(&new->console
.ringbuf
, 0, sizeof(struct lxc_ringbuf
));
3367 new->maincmd_fd
= -1;
3368 new->monitor_signal_pdeath
= SIGKILL
;
3370 new->rootfs
.mount
= strdup(default_rootfs_mount
);
3371 if (!new->rootfs
.mount
) {
3375 new->rootfs
.managed
= true;
3376 new->rootfs
.dfd_mnt
= -EBADF
;
3377 new->rootfs
.dfd_dev
= -EBADF
;
3378 new->rootfs
.dfd_host
= -EBADF
;
3379 new->rootfs
.fd_path_pin
= -EBADF
;
3380 new->rootfs
.dfd_idmapped
= -EBADF
;
3382 INIT_LIST_HEAD(&new->cgroup
);
3383 INIT_LIST_HEAD(&new->cgroup2
);
3384 /* Block ("allowlist") all devices by default. */
3385 new->bpf_devices
.list_type
= LXC_BPF_DEVICE_CGROUP_ALLOWLIST
;
3386 INIT_LIST_HEAD(&(new->bpf_devices
).devices
);
3387 lxc_list_init(&new->mount_list
);
3388 lxc_list_init(&new->caps
);
3389 lxc_list_init(&new->keepcaps
);
3390 INIT_LIST_HEAD(&new->id_map
);
3391 new->root_nsuid_map
= NULL
;
3392 new->root_nsgid_map
= NULL
;
3393 lxc_list_init(&new->includes
);
3394 lxc_list_init(&new->aliens
);
3395 lxc_list_init(&new->environment
);
3396 INIT_LIST_HEAD(&new->limits
);
3397 INIT_LIST_HEAD(&new->sysctls
);
3398 INIT_LIST_HEAD(&new->procs
);
3399 new->hooks_version
= 0;
3400 for (i
= 0; i
< NUM_LXC_HOOKS
; i
++)
3401 lxc_list_init(&new->hooks
[i
]);
3402 lxc_list_init(&new->groups
);
3403 INIT_LIST_HEAD(&new->state_clients
);
3404 new->lsm_aa_profile
= NULL
;
3405 lxc_list_init(&new->lsm_aa_raw
);
3406 new->lsm_se_context
= NULL
;
3407 new->lsm_se_keyring_context
= NULL
;
3408 new->keyring_disable_session
= false;
3409 new->transient_procfs_mnt
= false;
3410 new->shmount
.path_host
= NULL
;
3411 new->shmount
.path_cont
= NULL
;
3413 /* if running in a new user namespace, init and COMMAND
3414 * default to running as UID/GID 0 when using lxc-execute */
3417 memset(&new->init_groups
, 0, sizeof(lxc_groups_t
));
3418 memset(&new->cgroup_meta
, 0, sizeof(struct lxc_cgroup
));
3419 memset(&new->ns_share
, 0, sizeof(char *) * LXC_NS_MAX
);
3420 memset(&new->timens
, 0, sizeof(struct timens_offsets
));
3421 seccomp_conf_init(new);
3423 INIT_LIST_HEAD(&new->netdevs
);
3428 int write_id_mapping(enum idtype idtype
, pid_t pid
, const char *buf
,
3431 __do_close
int fd
= -EBADF
;
3433 char path
[PATH_MAX
];
3435 if (geteuid() != 0 && idtype
== ID_TYPE_GID
) {
3436 __do_close
int setgroups_fd
= -EBADF
;
3438 ret
= strnprintf(path
, sizeof(path
), "/proc/%d/setgroups", pid
);
3442 setgroups_fd
= open(path
, O_WRONLY
);
3443 if (setgroups_fd
< 0 && errno
!= ENOENT
)
3444 return log_error_errno(-1, errno
, "Failed to open \"%s\"", path
);
3446 if (setgroups_fd
>= 0) {
3447 ret
= lxc_write_nointr(setgroups_fd
, "deny\n",
3448 STRLITERALLEN("deny\n"));
3449 if (ret
!= STRLITERALLEN("deny\n"))
3450 return log_error_errno(-1, errno
, "Failed to write \"deny\" to \"/proc/%d/setgroups\"", pid
);
3451 TRACE("Wrote \"deny\" to \"/proc/%d/setgroups\"", pid
);
3455 ret
= strnprintf(path
, sizeof(path
), "/proc/%d/%cid_map", pid
,
3456 idtype
== ID_TYPE_UID
? 'u' : 'g');
3460 fd
= open(path
, O_WRONLY
| O_CLOEXEC
);
3462 return log_error_errno(-1, errno
, "Failed to open \"%s\"", path
);
3464 ret
= lxc_write_nointr(fd
, buf
, buf_size
);
3465 if (ret
!= buf_size
)
3466 return log_error_errno(-1, errno
, "Failed to write %cid mapping to \"%s\"",
3467 idtype
== ID_TYPE_UID
? 'u' : 'g', path
);
3472 /* Check whether a binary exist and has either CAP_SETUID, CAP_SETGID or both.
3474 * @return 1 if functional binary was found
3475 * @return 0 if binary exists but is lacking privilege
3476 * @return -ENOENT if binary does not exist
3477 * @return -EINVAL if cap to check is neither CAP_SETUID nor CAP_SETGID
3479 static int idmaptool_on_path_and_privileged(const char *binary
, cap_value_t cap
)
3481 __do_free
char *path
= NULL
;
3485 if (cap
!= CAP_SETUID
&& cap
!= CAP_SETGID
)
3486 return ret_errno(EINVAL
);
3488 path
= on_path(binary
, NULL
);
3490 return ret_errno(ENOENT
);
3492 ret
= stat(path
, &st
);
3496 /* Check if the binary is setuid. */
3497 if (st
.st_mode
& S_ISUID
)
3498 return log_debug(1, "The binary \"%s\" does have the setuid bit set", path
);
3500 #if HAVE_LIBCAP && LIBCAP_SUPPORTS_FILE_CAPABILITIES
3501 /* Check if it has the CAP_SETUID capability. */
3502 if ((cap
& CAP_SETUID
) &&
3503 lxc_file_cap_is_set(path
, CAP_SETUID
, CAP_EFFECTIVE
) &&
3504 lxc_file_cap_is_set(path
, CAP_SETUID
, CAP_PERMITTED
))
3505 return log_debug(1, "The binary \"%s\" has CAP_SETUID in its CAP_EFFECTIVE and CAP_PERMITTED sets", path
);
3507 /* Check if it has the CAP_SETGID capability. */
3508 if ((cap
& CAP_SETGID
) &&
3509 lxc_file_cap_is_set(path
, CAP_SETGID
, CAP_EFFECTIVE
) &&
3510 lxc_file_cap_is_set(path
, CAP_SETGID
, CAP_PERMITTED
))
3511 return log_debug(1, "The binary \"%s\" has CAP_SETGID in its CAP_EFFECTIVE and CAP_PERMITTED sets", path
);
3516 * If we cannot check for file capabilities we need to give the benefit
3517 * of the doubt. Otherwise we might fail even though all the necessary
3518 * file capabilities are set.
3520 DEBUG("Cannot check for file capabilities as full capability support is missing. Manual intervention needed");
3525 static int lxc_map_ids_exec_wrapper(void *args
)
3527 execl("/bin/sh", "sh", "-c", (char *)args
, (char *)NULL
);
3531 static struct id_map
*find_mapped_hostid_entry(const struct list_head
*idmap
,
3532 unsigned id
, enum idtype idtype
);
3534 int lxc_map_ids(struct list_head
*idmap
, pid_t pid
)
3536 int hostuid
, hostgid
, fill
, left
;
3539 char cmd_output
[PATH_MAX
];
3542 int ret
= 0, gidmap
= 0, uidmap
= 0;
3543 char mapbuf
[STRLITERALLEN("new@idmap") + STRLITERALLEN(" ") +
3544 INTTYPE_TO_STRLEN(pid_t
) + STRLITERALLEN(" ") +
3545 LXC_IDMAPLEN
] = {0};
3546 bool had_entry
= false, maps_host_root
= false, use_shadow
= false;
3548 hostuid
= geteuid();
3549 hostgid
= getegid();
3552 * Check whether caller wants to map host root.
3553 * Due to a security fix newer kernels require CAP_SETFCAP when mapping
3554 * host root into the child userns as you would be able to write fscaps
3555 * that would be valid in the ancestor userns. Mapping host root should
3556 * rarely be the case but LXC is being clever in a bunch of cases.
3558 if (find_mapped_hostid_entry(idmap
, 0, ID_TYPE_UID
))
3559 maps_host_root
= true;
3561 /* If new{g,u}idmap exists, that is, if shadow is handing out subuid
3562 * ranges, then insist that root also reserve ranges in subuid. This
3563 * will protected it by preventing another user from being handed the
3566 uidmap
= idmaptool_on_path_and_privileged("newuidmap", CAP_SETUID
);
3567 if (uidmap
== -ENOENT
)
3568 WARN("newuidmap binary is missing");
3570 WARN("newuidmap is lacking necessary privileges");
3572 gidmap
= idmaptool_on_path_and_privileged("newgidmap", CAP_SETGID
);
3573 if (gidmap
== -ENOENT
)
3574 WARN("newgidmap binary is missing");
3576 WARN("newgidmap is lacking necessary privileges");
3578 if (maps_host_root
) {
3579 INFO("Caller maps host root. Writing mapping directly");
3580 } else if (uidmap
> 0 && gidmap
> 0) {
3581 DEBUG("Functional newuidmap and newgidmap binary found");
3584 /* In case unprivileged users run application containers via
3585 * execute() or a start*() there are valid cases where they may
3586 * only want to map their own {g,u}id. Let's not block them from
3587 * doing so by requiring geteuid() == 0.
3589 DEBUG("No newuidmap and newgidmap binary found. Trying to "
3590 "write directly with euid %d", hostuid
);
3593 /* Check if we really need to use newuidmap and newgidmap.
3594 * If the user is only remapping their own {g,u}id, we don't need it.
3596 if (use_shadow
&& list_len(idmap
) == 2) {
3598 list_for_each_entry(map
, idmap
, head
) {
3599 if (map
->idtype
== ID_TYPE_UID
&& map
->range
== 1 &&
3600 map
->nsid
== hostuid
&& map
->hostid
== hostuid
)
3602 if (map
->idtype
== ID_TYPE_GID
&& map
->range
== 1 &&
3603 map
->nsid
== hostgid
&& map
->hostid
== hostgid
)
3610 for (type
= ID_TYPE_UID
, u_or_g
= 'u'; type
<= ID_TYPE_GID
;
3611 type
++, u_or_g
= 'g') {
3615 pos
+= sprintf(mapbuf
, "new%cidmap %d", u_or_g
, pid
);
3617 list_for_each_entry(map
, idmap
, head
) {
3618 if (map
->idtype
!= type
)
3623 left
= LXC_IDMAPLEN
- (pos
- mapbuf
);
3624 fill
= strnprintf(pos
, left
, "%s%lu %lu %lu%s",
3625 use_shadow
? " " : "", map
->nsid
,
3626 map
->hostid
, map
->range
,
3627 use_shadow
? "" : "\n");
3629 * The kernel only takes <= 4k for writes to
3630 * /proc/<pid>/{g,u}id_map
3633 return log_error_errno(-1, errno
, "Too many %cid mappings defined", u_or_g
);
3640 /* Try to catch the output of new{g,u}idmap to make debugging
3644 ret
= run_command(cmd_output
, sizeof(cmd_output
),
3645 lxc_map_ids_exec_wrapper
,
3648 return log_error(-1, "new%cidmap failed to write mapping \"%s\": %s", u_or_g
, cmd_output
, mapbuf
);
3649 TRACE("new%cidmap wrote mapping \"%s\"", u_or_g
, mapbuf
);
3651 ret
= write_id_mapping(type
, pid
, mapbuf
, pos
- mapbuf
);
3653 return log_error(-1, "Failed to write mapping: %s", mapbuf
);
3654 TRACE("Wrote mapping \"%s\"", mapbuf
);
3657 memset(mapbuf
, 0, sizeof(mapbuf
));
3664 * Return the host uid/gid to which the container root is mapped in val.
3665 * Return true if id was found, false otherwise.
3667 static id_t
get_mapped_rootid(const struct lxc_conf
*conf
, enum idtype idtype
)
3672 if (idtype
== ID_TYPE_UID
)
3673 nsid
= (conf
->root_nsuid_map
!= NULL
) ? 0 : conf
->init_uid
;
3675 nsid
= (conf
->root_nsgid_map
!= NULL
) ? 0 : conf
->init_gid
;
3677 list_for_each_entry (map
, &conf
->id_map
, head
) {
3678 if (map
->idtype
!= idtype
)
3680 if (map
->nsid
!= nsid
)
3685 if (idtype
== ID_TYPE_UID
)
3686 return LXC_INVALID_UID
;
3688 return LXC_INVALID_GID
;
3691 int mapped_hostid(unsigned id
, const struct lxc_conf
*conf
, enum idtype idtype
)
3695 list_for_each_entry(map
, &conf
->id_map
, head
) {
3696 if (map
->idtype
!= idtype
)
3699 if (id
>= map
->hostid
&& id
< map
->hostid
+ map
->range
)
3700 return (id
- map
->hostid
) + map
->nsid
;
3706 int find_unmapped_nsid(const struct lxc_conf
*conf
, enum idtype idtype
)
3709 unsigned int freeid
= 0;
3712 list_for_each_entry(map
, &conf
->id_map
, head
) {
3713 if (map
->idtype
!= idtype
)
3716 if (freeid
>= map
->nsid
&& freeid
< map
->nsid
+ map
->range
) {
3717 freeid
= map
->nsid
+ map
->range
;
3726 * Mount a proc under @rootfs if proc self points to a pid other than
3727 * my own. This is needed to have a known-good proc mount for setting
3728 * up LSMs both at container startup and attach.
3730 * NOTE: not to be called from inside the container namespace!
3732 static int lxc_transient_proc(struct lxc_rootfs
*rootfs
)
3734 __do_close
int fd_proc
= -EBADF
;
3735 int link_to_pid
, link_len
, pid_self
, ret
;
3736 char link
[INTTYPE_TO_STRLEN(pid_t
) + 1];
3738 link_len
= readlinkat(rootfs
->dfd_mnt
, "proc/self", link
, sizeof(link
));
3740 ret
= mkdirat(rootfs
->dfd_mnt
, "proc", 0000);
3741 if (ret
< 0 && errno
!= EEXIST
)
3742 return log_error_errno(-errno
, errno
, "Failed to create %d(proc)", rootfs
->dfd_mnt
);
3745 } else if (link_len
>= sizeof(link
)) {
3746 return log_error_errno(-EIO
, EIO
, "Truncated link target");
3748 link
[link_len
] = '\0';
3750 pid_self
= lxc_raw_getpid();
3751 INFO("Caller's PID is %d; /proc/self points to %s", pid_self
, link
);
3753 ret
= lxc_safe_int(link
, &link_to_pid
);
3755 return log_error_errno(-ret
, ret
, "Failed to parse %s", link
);
3757 /* Correct procfs is already mounted. */
3758 if (link_to_pid
== pid_self
)
3759 return log_trace(0, "Correct procfs instance mounted");
3761 fd_proc
= open_at(rootfs
->dfd_mnt
, "proc", PROTECT_OPATH_DIRECTORY
,
3762 PROTECT_LOOKUP_BENEATH_XDEV
, 0);
3764 return log_error_errno(-errno
, errno
, "Failed to open transient procfs mountpoint");
3766 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "/proc/self/fd/%d", fd_proc
);
3768 return ret_errno(EIO
);
3770 ret
= umount2(rootfs
->buf
, MNT_DETACH
);
3772 SYSWARN("Failed to umount \"%s\" with MNT_DETACH", rootfs
->buf
);
3775 /* rootfs is NULL */
3776 if (!rootfs
->path
) {
3777 ret
= mount("proc", rootfs
->buf
, "proc", 0, NULL
);
3779 ret
= safe_mount_beneath_at(rootfs
->dfd_mnt
, "none", "proc", "proc", 0, NULL
);
3781 ret
= strnprintf(rootfs
->buf
, sizeof(rootfs
->buf
), "%s/proc", rootfs
->path
? rootfs
->mount
: "");
3783 return ret_errno(EIO
);
3785 ret
= safe_mount("proc", rootfs
->buf
, "proc", 0, NULL
, rootfs
->mount
);
3789 return log_error_errno(-1, errno
, "Failed to mount temporary procfs");
3791 INFO("Created transient procfs mount");
3795 /* NOTE: Must not be called from inside the container namespace! */
3796 static int lxc_create_tmp_proc_mount(struct lxc_conf
*conf
)
3800 mounted
= lxc_transient_proc(&conf
->rootfs
);
3801 if (mounted
== -1) {
3802 /* continue only if there is no rootfs */
3803 if (conf
->rootfs
.path
)
3804 return log_error_errno(-EPERM
, EPERM
, "Failed to create transient procfs mount");
3805 } else if (mounted
== 1) {
3806 conf
->transient_procfs_mnt
= true;
3812 void tmp_proc_unmount(struct lxc_conf
*lxc_conf
)
3814 if (lxc_conf
->transient_procfs_mnt
) {
3815 (void)umount2("/proc", MNT_DETACH
);
3816 lxc_conf
->transient_procfs_mnt
= false;
3820 /* Walk /proc/mounts and change any shared entries to dependent mounts. */
3821 static void turn_into_dependent_mounts(const struct lxc_rootfs
*rootfs
)
3823 __do_free
char *line
= NULL
;
3824 __do_fclose
FILE *f
= NULL
;
3825 __do_close
int memfd
= -EBADF
, mntinfo_fd
= -EBADF
;
3830 mntinfo_fd
= open_at(rootfs
->dfd_host
, "proc/self/mountinfo", PROTECT_OPEN
,
3831 (PROTECT_LOOKUP_BENEATH_XDEV
& ~RESOLVE_NO_SYMLINKS
), 0);
3832 if (mntinfo_fd
< 0) {
3833 SYSERROR("Failed to open %d/proc/self/mountinfo", rootfs
->dfd_host
);
3837 memfd
= memfd_create(".lxc_mountinfo", MFD_CLOEXEC
);
3839 char template[] = P_tmpdir
"/.lxc_mountinfo_XXXXXX";
3841 if (errno
!= ENOSYS
) {
3842 SYSERROR("Failed to create temporary in-memory file");
3846 memfd
= lxc_make_tmpfile(template, true);
3848 WARN("Failed to create temporary file");
3853 copied
= fd_to_fd(mntinfo_fd
, memfd
);
3855 SYSERROR("Failed to copy \"/proc/self/mountinfo\"");
3859 ret
= lseek(memfd
, 0, SEEK_SET
);
3861 SYSERROR("Failed to reset file descriptor offset");
3865 f
= fdopen(memfd
, "re");
3867 SYSERROR("Failed to open copy of \"/proc/self/mountinfo\" to mark all shared. Continuing");
3872 * After a successful fdopen() memfd will be closed when calling
3873 * fclose(f). Calling close(memfd) afterwards is undefined.
3877 while (getline(&line
, &len
, f
) != -1) {
3878 char *opts
, *target
;
3880 target
= get_field(line
, 4);
3884 opts
= get_field(target
, 2);
3888 null_endofword(opts
);
3889 if (!strstr(opts
, "shared"))
3892 null_endofword(target
);
3893 ret
= mount(NULL
, target
, NULL
, MS_SLAVE
, NULL
);
3895 SYSERROR("Failed to recursively turn old root mount tree into dependent mount. Continuing...");
3899 TRACE("Turned all mount table entries into dependent mount");
3902 /* This does the work of remounting / if it is shared, calling the container
3903 * pre-mount hooks, and mounting the rootfs.
3905 int lxc_setup_rootfs_prepare_root(struct lxc_conf
*conf
, const char *name
,
3906 const char *lxcpath
)
3910 conf
->rootfs
.dfd_host
= open_at(-EBADF
, "/", PROTECT_OPATH_DIRECTORY
, PROTECT_LOOKUP_ABSOLUTE
, 0);
3911 if (conf
->rootfs
.dfd_host
< 0)
3912 return log_error_errno(-errno
, errno
, "Failed to open \"/\"");
3914 turn_into_dependent_mounts(&conf
->rootfs
);
3916 if (conf
->rootfs_setup
) {
3917 const char *path
= conf
->rootfs
.mount
;
3920 * The rootfs was set up in another namespace. bind-mount it to
3921 * give us a mount in our own ns so we can pivot_root to it
3923 ret
= mount(path
, path
, "rootfs", MS_BIND
, NULL
);
3925 return log_error(-1, "Failed to bind mount container / onto itself");
3927 conf
->rootfs
.dfd_mnt
= openat(-EBADF
, path
, O_RDONLY
| O_CLOEXEC
| O_DIRECTORY
| O_PATH
| O_NOCTTY
);
3928 if (conf
->rootfs
.dfd_mnt
< 0)
3929 return log_error_errno(-errno
, errno
, "Failed to open file descriptor for container rootfs");
3931 return log_trace(0, "Bind mounted container / onto itself");
3934 ret
= run_lxc_hooks(name
, "pre-mount", conf
, NULL
);
3936 return log_error(-1, "Failed to run pre-mount hooks");
3938 ret
= lxc_mount_rootfs(&conf
->rootfs
);
3940 return log_error(-1, "Failed to setup rootfs for");
3942 conf
->rootfs_setup
= true;
3946 static bool verify_start_hooks(struct lxc_conf
*conf
)
3948 char path
[PATH_MAX
];
3949 struct lxc_list
*it
;
3951 lxc_list_for_each (it
, &conf
->hooks
[LXCHOOK_START
]) {
3953 char *hookname
= it
->elem
;
3955 ret
= strnprintf(path
, sizeof(path
), "%s%s",
3956 conf
->rootfs
.path
? conf
->rootfs
.mount
: "",
3961 ret
= access(path
, X_OK
);
3963 return log_error_errno(false, errno
, "Start hook \"%s\" not found in container", hookname
);
3971 static int lxc_setup_boot_id(void)
3974 const char *boot_id_path
= "/proc/sys/kernel/random/boot_id";
3975 const char *mock_boot_id_path
= "/dev/.lxc-boot-id";
3978 if (access(boot_id_path
, F_OK
))
3981 memset(&n
, 0, sizeof(n
));
3982 if (lxc_id128_randomize(&n
)) {
3983 SYSERROR("Failed to generate random data for uuid");
3987 ret
= lxc_id128_write(mock_boot_id_path
, n
);
3989 SYSERROR("Failed to write uuid to %s", mock_boot_id_path
);
3993 ret
= chmod(mock_boot_id_path
, 0444);
3995 SYSERROR("Failed to chown %s", mock_boot_id_path
);
3996 (void)unlink(mock_boot_id_path
);
4000 ret
= mount(mock_boot_id_path
, boot_id_path
, NULL
, MS_BIND
, NULL
);
4002 SYSERROR("Failed to mount %s to %s", mock_boot_id_path
,
4004 (void)unlink(mock_boot_id_path
);
4008 ret
= mount(NULL
, boot_id_path
, NULL
,
4009 (MS_BIND
| MS_REMOUNT
| MS_RDONLY
| MS_NOSUID
| MS_NOEXEC
|
4013 SYSERROR("Failed to remount %s read-only", boot_id_path
);
4014 (void)unlink(mock_boot_id_path
);
4021 static int lxc_setup_keyring(struct lsm_ops
*lsm_ops
, const struct lxc_conf
*conf
)
4023 key_serial_t keyring
;
4026 if (conf
->lsm_se_keyring_context
)
4027 ret
= lsm_ops
->keyring_label_set(lsm_ops
, conf
->lsm_se_keyring_context
);
4028 else if (conf
->lsm_se_context
)
4029 ret
= lsm_ops
->keyring_label_set(lsm_ops
, conf
->lsm_se_context
);
4031 return syserror("Failed to set keyring context");
4034 * Try to allocate a new session keyring for the container to prevent
4035 * information leaks.
4037 keyring
= keyctl(KEYCTL_JOIN_SESSION_KEYRING
, prctl_arg(0),
4038 prctl_arg(0), prctl_arg(0), prctl_arg(0));
4042 DEBUG("The keyctl() syscall is not supported or blocked");
4047 DEBUG("Failed to access kernel keyring. Continuing...");
4050 SYSWARN("Failed to create kernel keyring");
4058 static int lxc_rootfs_prepare_child(struct lxc_handler
*handler
)
4060 struct lxc_rootfs
*rootfs
= &handler
->conf
->rootfs
;
4061 int dfd_idmapped
= -EBADF
;
4064 if (list_empty(&handler
->conf
->id_map
))
4067 if (is_empty_string(rootfs
->mnt_opts
.userns_path
))
4070 if (handler
->conf
->rootfs_setup
)
4073 ret
= lxc_abstract_unix_recv_one_fd(handler
->data_sock
[1], &dfd_idmapped
, NULL
, 0);
4075 return syserror("Failed to receive idmapped mount fd");
4077 rootfs
->dfd_idmapped
= dfd_idmapped
;
4078 TRACE("Received detached idmapped mount %d", rootfs
->dfd_idmapped
);
4082 int lxc_idmapped_mounts_parent(struct lxc_handler
*handler
)
4087 __do_close
int fd_from
= -EBADF
, fd_userns
= -EBADF
;
4088 struct lxc_mount_attr attr
= {};
4089 struct lxc_mount_options opts
= {};
4092 ret
= __lxc_abstract_unix_recv_two_fds(handler
->data_sock
[1],
4093 &fd_from
, &fd_userns
,
4094 &opts
, sizeof(opts
));
4096 return syserror("Failed to receive idmapped mount file descriptors from child");
4098 if (fd_from
< 0 || fd_userns
< 0)
4099 return log_trace(0, "Finished receiving idmapped mount file descriptors from child");
4101 attr
.attr_set
= MOUNT_ATTR_IDMAP
;
4102 attr
.userns_fd
= fd_userns
;
4103 ret
= mount_setattr(fd_from
, "",
4105 (opts
.bind_recursively
? AT_RECURSIVE
: 0),
4106 &attr
, sizeof(attr
));
4108 return syserror("Failed to idmap detached %smount %d to %d",
4109 opts
.bind_recursively
? "recursive " : "",
4110 fd_from
, fd_userns
);
4112 ret
= lxc_abstract_unix_send_credential(handler
->data_sock
[1],
4116 return syserror("Parent failed to notify child that detached %smount %d was idmapped to user namespace %d",
4117 opts
.bind_recursively
? "recursive " : "",
4118 fd_from
, fd_userns
);
4120 TRACE("Parent idmapped detached %smount %d to user namespace %d",
4121 opts
.bind_recursively
? "recursive " : "", fd_from
, fd_userns
);
4126 static int lxc_recv_ttys_from_child(struct lxc_handler
*handler
)
4128 call_cleaner(lxc_delete_tty
) struct lxc_tty_info
*info_new
= &(struct lxc_tty_info
){};
4129 int sock
= handler
->data_sock
[1];
4130 struct lxc_conf
*conf
= handler
->conf
;
4131 struct lxc_tty_info
*tty_info
= &conf
->ttys
;
4132 size_t ttys_max
= tty_info
->max
;
4133 struct lxc_terminal_info
*terminal_info
;
4139 info_new
->tty
= malloc(sizeof(*(info_new
->tty
)) * ttys_max
);
4141 return ret_errno(ENOMEM
);
4143 for (int i
= 0; i
< ttys_max
; i
++) {
4144 terminal_info
= &info_new
->tty
[i
];
4145 terminal_info
->busy
= -1;
4146 terminal_info
->ptx
= -EBADF
;
4147 terminal_info
->pty
= -EBADF
;
4150 for (int i
= 0; i
< ttys_max
; i
++) {
4151 int ptx
= -EBADF
, pty
= -EBADF
;
4153 ret
= lxc_abstract_unix_recv_two_fds(sock
, &ptx
, &pty
);
4155 return syserror("Failed to receive %zu ttys from child", ttys_max
);
4157 terminal_info
= &info_new
->tty
[i
];
4158 terminal_info
->ptx
= ptx
;
4159 terminal_info
->pty
= pty
;
4160 TRACE("Received pty with ptx fd %d and pty fd %d from child",
4161 terminal_info
->ptx
, terminal_info
->pty
);
4164 tty_info
->tty
= move_ptr(info_new
->tty
);
4165 TRACE("Received %zu ttys from child", ttys_max
);
4169 static int lxc_send_console_to_parent(struct lxc_handler
*handler
)
4171 struct lxc_terminal
*console
= &handler
->conf
->console
;
4174 if (!wants_console(console
))
4177 /* We've already allocated a console from the host's devpts instance. */
4178 if (console
->pty
< 0)
4181 ret
= __lxc_abstract_unix_send_two_fds(handler
->data_sock
[0],
4182 console
->ptx
, console
->pty
,
4184 sizeof(struct lxc_terminal
));
4186 return syserror("Fail to send console to parent");
4188 TRACE("Sent console to parent");
4192 static int lxc_recv_console_from_child(struct lxc_handler
*handler
)
4194 __do_close
int fd_ptx
= -EBADF
, fd_pty
= -EBADF
;
4195 struct lxc_terminal
*console
= &handler
->conf
->console
;
4198 if (!wants_console(console
))
4201 /* We've already allocated a console from the host's devpts instance. */
4202 if (console
->pty
>= 0)
4205 ret
= __lxc_abstract_unix_recv_two_fds(handler
->data_sock
[1],
4208 sizeof(struct lxc_terminal
));
4210 return syserror("Fail to receive console from child");
4212 console
->ptx
= move_fd(fd_ptx
);
4213 console
->pty
= move_fd(fd_pty
);
4215 TRACE("Received console from child");
4219 int lxc_sync_fds_parent(struct lxc_handler
*handler
)
4223 ret
= lxc_seccomp_recv_notifier_fd(&handler
->conf
->seccomp
, handler
->data_sock
[1]);
4225 return syserror_ret(ret
, "Failed to receive seccomp notify fd from child");
4227 ret
= lxc_recv_devpts_from_child(handler
);
4229 return syserror_ret(ret
, "Failed to receive devpts fd from child");
4231 /* Read tty fds allocated by child. */
4232 ret
= lxc_recv_ttys_from_child(handler
);
4234 return syserror_ret(ret
, "Failed to receive tty info from child process");
4236 if (handler
->ns_clone_flags
& CLONE_NEWNET
) {
4237 ret
= lxc_network_recv_name_and_ifindex_from_child(handler
);
4239 return syserror_ret(ret
, "Failed to receive names and ifindices for network devices from child");
4242 ret
= lxc_recv_console_from_child(handler
);
4244 return syserror_ret(ret
, "Failed to receive console from child");
4246 TRACE("Finished syncing file descriptors with child");
4250 int lxc_sync_fds_child(struct lxc_handler
*handler
)
4254 ret
= lxc_seccomp_send_notifier_fd(&handler
->conf
->seccomp
, handler
->data_sock
[0]);
4256 return syserror_ret(ret
, "Failed to send seccomp notify fd to parent");
4258 ret
= lxc_send_devpts_to_parent(handler
);
4260 return syserror_ret(ret
, "Failed to send seccomp devpts fd to parent");
4262 ret
= lxc_send_ttys_to_parent(handler
);
4264 return syserror_ret(ret
, "Failed to send tty file descriptors to parent");
4266 if (handler
->ns_clone_flags
& CLONE_NEWNET
) {
4267 ret
= lxc_network_send_name_and_ifindex_to_parent(handler
);
4269 return syserror_ret(ret
, "Failed to send network device names and ifindices to parent");
4272 ret
= lxc_send_console_to_parent(handler
);
4274 return syserror_ret(ret
, "Failed to send console to parent");
4276 TRACE("Finished syncing file descriptors with parent");
4280 int lxc_setup(struct lxc_handler
*handler
)
4283 const char *lxcpath
= handler
->lxcpath
, *name
= handler
->name
;
4284 struct lxc_conf
*lxc_conf
= handler
->conf
;
4286 ret
= lxc_rootfs_prepare_child(handler
);
4288 return syserror("Failed to prepare rootfs");
4290 ret
= lxc_setup_rootfs_prepare_root(lxc_conf
, name
, lxcpath
);
4292 return log_error(-1, "Failed to setup rootfs");
4294 if (handler
->nsfd
[LXC_NS_UTS
] == -EBADF
) {
4295 ret
= setup_utsname(lxc_conf
->utsname
);
4297 return log_error(-1, "Failed to setup the utsname %s", name
);
4300 if (!lxc_conf
->keyring_disable_session
) {
4301 ret
= lxc_setup_keyring(handler
->lsm_ops
, lxc_conf
);
4303 return log_error(-1, "Failed to setup container keyring");
4306 if (handler
->ns_clone_flags
& CLONE_NEWNET
) {
4307 ret
= lxc_network_recv_from_parent(handler
);
4309 return log_error(-1, "Failed to receive veth names from parent");
4311 ret
= lxc_setup_network_in_child_namespaces(lxc_conf
);
4313 return log_error(-1, "Failed to setup network");
4316 if (lxc_conf
->autodev
> 0) {
4317 ret
= mount_autodev(name
, &lxc_conf
->rootfs
, lxc_conf
->autodevtmpfssize
, lxcpath
);
4319 return log_error(-1, "Failed to mount \"/dev\"");
4322 /* Do automatic mounts (mainly /proc and /sys), but exclude those that
4323 * need to wait until other stuff has finished.
4325 ret
= lxc_mount_auto_mounts(handler
, lxc_conf
->auto_mounts
& ~LXC_AUTO_CGROUP_MASK
);
4327 return log_error(-1, "Failed to setup first automatic mounts");
4329 ret
= setup_mount_fstab(&lxc_conf
->rootfs
, lxc_conf
->fstab
, name
, lxcpath
);
4331 return log_error(-1, "Failed to setup mounts");
4333 if (!lxc_list_empty(&lxc_conf
->mount_list
)) {
4334 ret
= setup_mount_entries(lxc_conf
, &lxc_conf
->rootfs
,
4335 &lxc_conf
->mount_list
, name
, lxcpath
);
4337 return log_error(-1, "Failed to setup mount entries");
4340 if (!lxc_sync_wake_parent(handler
, START_SYNC_IDMAPPED_MOUNTS
))
4343 ret
= lxc_idmapped_mounts_child(handler
);
4345 return syserror("Failed to attached detached idmapped mounts");
4347 lxc_conf
->rootfs
.dfd_dev
= open_at(lxc_conf
->rootfs
.dfd_mnt
, "dev",
4348 PROTECT_OPATH_DIRECTORY
, PROTECT_LOOKUP_BENEATH_XDEV
, 0);
4349 if (lxc_conf
->rootfs
.dfd_dev
< 0 && errno
!= ENOENT
)
4350 return log_error_errno(-errno
, errno
, "Failed to open \"/dev\"");
4352 /* Now mount only cgroups, if wanted. Before, /sys could not have been
4353 * mounted. It is guaranteed to be mounted now either through
4354 * automatically or via fstab entries.
4356 ret
= lxc_mount_auto_mounts(handler
, lxc_conf
->auto_mounts
& LXC_AUTO_CGROUP_MASK
);
4358 return log_error(-1, "Failed to setup remaining automatic mounts");
4360 ret
= run_lxc_hooks(name
, "mount", lxc_conf
, NULL
);
4362 return log_error(-1, "Failed to run mount hooks");
4364 if (lxc_conf
->autodev
> 0) {
4365 ret
= run_lxc_hooks(name
, "autodev", lxc_conf
, NULL
);
4367 return log_error(-1, "Failed to run autodev hooks");
4369 ret
= lxc_fill_autodev(&lxc_conf
->rootfs
);
4371 return log_error(-1, "Failed to populate \"/dev\"");
4374 /* Make sure any start hooks are in the container */
4375 if (!verify_start_hooks(lxc_conf
))
4376 return log_error(-1, "Failed to verify start hooks");
4378 ret
= lxc_create_tmp_proc_mount(lxc_conf
);
4380 return log_error(-1, "Failed to mount transient procfs instance for LSMs");
4382 ret
= lxc_setup_devpts_child(handler
);
4384 return log_error(-1, "Failed to prepare new devpts instance");
4386 ret
= lxc_finish_devpts_child(handler
);
4388 return log_error(-1, "Failed to finish devpts setup");
4390 ret
= lxc_setup_console(handler
, &lxc_conf
->rootfs
, &lxc_conf
->console
,
4391 lxc_conf
->ttys
.dir
);
4393 return log_error(-1, "Failed to setup console");
4395 ret
= lxc_create_ttys(handler
);
4397 return log_error(-1, "Failed to create ttys");
4399 ret
= lxc_setup_dev_symlinks(&lxc_conf
->rootfs
);
4401 return log_error(-1, "Failed to setup \"/dev\" symlinks");
4403 ret
= lxc_setup_rootfs_switch_root(&lxc_conf
->rootfs
);
4405 return log_error(-1, "Failed to pivot root into rootfs");
4407 /* Setting the boot-id is best-effort for now. */
4408 if (lxc_conf
->autodev
> 0)
4409 (void)lxc_setup_boot_id();
4411 ret
= setup_personality(lxc_conf
->personality
);
4413 return syserror("Failed to set personality");
4415 /* Set sysctl value to a path under /proc/sys as determined from the
4416 * key. For e.g. net.ipv4.ip_forward translated to
4417 * /proc/sys/net/ipv4/ip_forward.
4419 ret
= setup_sysctl_parameters(lxc_conf
);
4421 return log_error(-1, "Failed to setup sysctl parameters");
4423 if (!lxc_list_empty(&lxc_conf
->keepcaps
)) {
4424 if (!lxc_list_empty(&lxc_conf
->caps
))
4425 return log_error(-1, "Container requests lxc.cap.drop and lxc.cap.keep: either use lxc.cap.drop or lxc.cap.keep, not both");
4427 if (dropcaps_except(&lxc_conf
->keepcaps
))
4428 return log_error(-1, "Failed to keep capabilities");
4429 } else if (setup_caps(&lxc_conf
->caps
)) {
4430 return log_error(-1, "Failed to drop capabilities");
4433 put_lxc_rootfs(&handler
->conf
->rootfs
, true);
4434 NOTICE("The container \"%s\" is set up", name
);
4439 int run_lxc_hooks(const char *name
, char *hookname
, struct lxc_conf
*conf
,
4442 struct lxc_list
*it
;
4445 for (which
= 0; which
< NUM_LXC_HOOKS
; which
++) {
4446 if (strequal(hookname
, lxchook_names
[which
]))
4450 if (which
>= NUM_LXC_HOOKS
)
4453 lxc_list_for_each (it
, &conf
->hooks
[which
]) {
4455 char *hook
= it
->elem
;
4457 ret
= run_script_argv(name
, conf
->hooks_version
, "lxc", hook
,
4466 int lxc_clear_config_caps(struct lxc_conf
*c
)
4468 struct lxc_list
*it
, *next
;
4470 lxc_list_for_each_safe (it
, &c
->caps
, next
) {
4476 lxc_list_init(&c
->caps
);
4480 static int lxc_free_idmap(struct list_head
*id_map
)
4482 struct id_map
*map
, *nmap
;
4484 list_for_each_entry_safe(map
, nmap
, id_map
, head
) {
4485 list_del(&map
->head
);
4489 INIT_LIST_HEAD(id_map
);
4493 static int __lxc_free_idmap(struct list_head
*id_map
)
4495 lxc_free_idmap(id_map
);
4498 define_cleanup_function(struct list_head
*, __lxc_free_idmap
);
4500 int lxc_clear_idmaps(struct lxc_conf
*c
)
4502 return lxc_free_idmap(&c
->id_map
);
4505 int lxc_clear_config_keepcaps(struct lxc_conf
*c
)
4507 struct lxc_list
*it
, *next
;
4509 lxc_list_for_each_safe (it
, &c
->keepcaps
, next
) {
4515 lxc_list_init(&c
->keepcaps
);
4519 int lxc_clear_namespace(struct lxc_conf
*c
)
4521 for (int i
= 0; i
< LXC_NS_MAX
; i
++)
4522 free_disarm(c
->ns_share
[i
]);
4527 int lxc_clear_cgroups(struct lxc_conf
*c
, const char *key
, int version
)
4529 const char *k
= key
;
4531 char *global_token
, *namespaced_token
;
4532 size_t namespaced_token_len
;
4533 struct list_head
*list
;
4534 struct lxc_cgroup
*cgroup
, *ncgroup
;
4536 if (version
== CGROUP2_SUPER_MAGIC
) {
4537 global_token
= "lxc.cgroup2";
4538 namespaced_token
= "lxc.cgroup2.";
4539 namespaced_token_len
= STRLITERALLEN("lxc.cgroup2.");
4541 } else if (version
== CGROUP_SUPER_MAGIC
) {
4542 global_token
= "lxc.cgroup";
4543 namespaced_token
= "lxc.cgroup.";
4544 namespaced_token_len
= STRLITERALLEN("lxc.cgroup.");
4547 return ret_errno(EINVAL
);
4550 if (strequal(key
, global_token
))
4552 else if (strnequal(key
, namespaced_token
, namespaced_token_len
))
4553 k
+= namespaced_token_len
;
4555 return ret_errno(EINVAL
);
4557 list_for_each_entry_safe(cgroup
, ncgroup
, list
, head
) {
4558 if (!all
&& !strequal(cgroup
->subsystem
, k
))
4561 list_del(&cgroup
->head
);
4562 free(cgroup
->subsystem
);
4563 free(cgroup
->value
);
4568 INIT_LIST_HEAD(list
);
4573 static inline void lxc_clear_cgroups_devices(struct lxc_conf
*conf
)
4575 lxc_clear_cgroup2_devices(&conf
->bpf_devices
);
4578 int lxc_clear_limits(struct lxc_conf
*c
, const char *key
)
4580 const char *k
= NULL
;
4582 struct lxc_limit
*lim
, *nlim
;
4584 if (strequal(key
, "lxc.limit") || strequal(key
, "lxc.prlimit"))
4586 else if (strnequal(key
, "lxc.limit.", STRLITERALLEN("lxc.limit.")))
4587 k
= key
+ STRLITERALLEN("lxc.limit.");
4588 else if (strnequal(key
, "lxc.prlimit.", STRLITERALLEN("lxc.prlimit.")))
4589 k
= key
+ STRLITERALLEN("lxc.prlimit.");
4591 return ret_errno(EINVAL
);
4593 list_for_each_entry_safe(lim
, nlim
, &c
->limits
, head
) {
4594 if (!all
&& !strequal(lim
->resource
, k
))
4597 list_del(&lim
->head
);
4598 free_disarm(lim
->resource
);
4603 INIT_LIST_HEAD(&c
->limits
);
4608 int lxc_clear_sysctls(struct lxc_conf
*c
, const char *key
)
4610 const char *k
= NULL
;
4612 struct lxc_sysctl
*sysctl
, *nsysctl
;
4614 if (strequal(key
, "lxc.sysctl"))
4616 else if (strnequal(key
, "lxc.sysctl.", STRLITERALLEN("lxc.sysctl.")))
4617 k
= key
+ STRLITERALLEN("lxc.sysctl.");
4621 list_for_each_entry_safe(sysctl
, nsysctl
, &c
->sysctls
, head
) {
4622 if (!all
&& !strequal(sysctl
->key
, k
))
4625 list_del(&sysctl
->head
);
4627 free(sysctl
->value
);
4632 INIT_LIST_HEAD(&c
->sysctls
);
4637 int lxc_clear_procs(struct lxc_conf
*c
, const char *key
)
4639 const char *k
= NULL
;
4641 struct lxc_proc
*proc
, *nproc
;
4643 if (strequal(key
, "lxc.proc"))
4645 else if (strnequal(key
, "lxc.proc.", STRLITERALLEN("lxc.proc.")))
4646 k
= key
+ STRLITERALLEN("lxc.proc.");
4650 list_for_each_entry_safe(proc
, nproc
, &c
->procs
, head
) {
4651 if (!all
&& !strequal(proc
->filename
, k
))
4654 list_del(&proc
->head
);
4655 free(proc
->filename
);
4661 INIT_LIST_HEAD(&c
->procs
);
4666 int lxc_clear_groups(struct lxc_conf
*c
)
4668 struct lxc_list
*it
, *next
;
4670 lxc_list_for_each_safe (it
, &c
->groups
, next
) {
4676 lxc_list_init(&c
->groups
);
4680 int lxc_clear_environment(struct lxc_conf
*c
)
4682 struct lxc_list
*it
, *next
;
4684 lxc_list_for_each_safe (it
, &c
->environment
, next
) {
4690 lxc_list_init(&c
->environment
);
4694 int lxc_clear_mount_entries(struct lxc_conf
*c
)
4696 struct lxc_list
*it
, *next
;
4698 lxc_list_for_each_safe (it
, &c
->mount_list
, next
) {
4704 lxc_list_init(&c
->mount_list
);
4708 int lxc_clear_automounts(struct lxc_conf
*c
)
4714 int lxc_clear_hooks(struct lxc_conf
*c
, const char *key
)
4716 struct lxc_list
*it
, *next
;
4717 const char *k
= NULL
;
4718 bool all
= false, done
= false;
4720 if (strequal(key
, "lxc.hook"))
4722 else if (strnequal(key
, "lxc.hook.", STRLITERALLEN("lxc.hook.")))
4723 k
= key
+ STRLITERALLEN("lxc.hook.");
4727 for (int i
= 0; i
< NUM_LXC_HOOKS
; i
++) {
4728 if (all
|| strequal(k
, lxchook_names
[i
])) {
4729 lxc_list_for_each_safe (it
, &c
->hooks
[i
], next
) {
4734 lxc_list_init(&c
->hooks
[i
]);
4741 return log_error(-1, "Invalid hook key: %s", key
);
4746 static inline void lxc_clear_aliens(struct lxc_conf
*conf
)
4748 struct lxc_list
*it
, *next
;
4750 lxc_list_for_each_safe (it
, &conf
->aliens
, next
) {
4756 lxc_list_init(&conf
->aliens
);
4759 void lxc_clear_includes(struct lxc_conf
*conf
)
4761 struct lxc_list
*it
, *next
;
4763 lxc_list_for_each_safe(it
, &conf
->includes
, next
) {
4769 lxc_list_init(&conf
->includes
);
4772 int lxc_clear_apparmor_raw(struct lxc_conf
*c
)
4774 struct lxc_list
*it
, *next
;
4776 lxc_list_for_each_safe (it
, &c
->lsm_aa_raw
, next
) {
4782 lxc_list_init(&c
->lsm_aa_raw
);
4786 void lxc_conf_free(struct lxc_conf
*conf
)
4791 if (current_config
== conf
)
4792 current_config
= NULL
;
4793 lxc_terminal_conf_free(&conf
->console
);
4794 free(conf
->rootfs
.mount
);
4795 free(conf
->rootfs
.bdev_type
);
4796 free(conf
->rootfs
.path
);
4797 put_lxc_rootfs(&conf
->rootfs
, true);
4798 free(conf
->logfile
);
4799 if (conf
->logfd
!= -1)
4801 free(conf
->utsname
);
4802 free(conf
->ttys
.dir
);
4803 free(conf
->ttys
.tty_names
);
4806 free(conf
->execute_cmd
);
4807 free(conf
->init_cmd
);
4808 free(conf
->init_groups
.list
);
4809 free(conf
->init_cwd
);
4810 free(conf
->unexpanded_config
);
4812 lxc_free_networks(conf
);
4813 free(conf
->lsm_aa_profile
);
4814 free(conf
->lsm_aa_profile_computed
);
4815 free(conf
->lsm_se_context
);
4816 free(conf
->lsm_se_keyring_context
);
4817 lxc_seccomp_free(&conf
->seccomp
);
4818 lxc_clear_config_caps(conf
);
4819 lxc_clear_config_keepcaps(conf
);
4820 lxc_clear_cgroups(conf
, "lxc.cgroup", CGROUP_SUPER_MAGIC
);
4821 lxc_clear_cgroups(conf
, "lxc.cgroup2", CGROUP2_SUPER_MAGIC
);
4822 lxc_clear_cgroups_devices(conf
);
4823 lxc_clear_hooks(conf
, "lxc.hook");
4824 lxc_clear_mount_entries(conf
);
4825 lxc_clear_idmaps(conf
);
4826 lxc_clear_groups(conf
);
4827 lxc_clear_includes(conf
);
4828 lxc_clear_aliens(conf
);
4829 lxc_clear_environment(conf
);
4830 lxc_clear_limits(conf
, "lxc.prlimit");
4831 lxc_clear_sysctls(conf
, "lxc.sysctl");
4832 lxc_clear_procs(conf
, "lxc.proc");
4833 lxc_clear_apparmor_raw(conf
);
4834 lxc_clear_namespace(conf
);
4835 free(conf
->cgroup_meta
.dir
);
4836 free(conf
->cgroup_meta
.monitor_dir
);
4837 free(conf
->cgroup_meta
.monitor_pivot_dir
);
4838 free(conf
->cgroup_meta
.container_dir
);
4839 free(conf
->cgroup_meta
.namespace_dir
);
4840 free(conf
->cgroup_meta
.controllers
);
4841 free(conf
->shmount
.path_host
);
4842 free(conf
->shmount
.path_cont
);
4846 struct userns_fn_data
{
4848 const char *fn_name
;
4853 static int run_userns_fn(void *data
)
4855 struct userns_fn_data
*d
= data
;
4859 close_prot_errno_disarm(d
->p
[1]);
4862 * Wait for parent to finish establishing a new mapping in the user
4863 * namespace we are executing in.
4865 ret
= lxc_read_nointr(d
->p
[0], &c
, 1);
4866 close_prot_errno_disarm(d
->p
[0]);
4871 TRACE("Calling function \"%s\"", d
->fn_name
);
4873 /* Call function to run. */
4874 return d
->fn(d
->arg
);
4877 static struct id_map
*mapped_nsid_add(const struct lxc_conf
*conf
, unsigned id
,
4880 const struct id_map
*map
;
4881 struct id_map
*retmap
;
4883 map
= find_mapped_nsid_entry(conf
, id
, idtype
);
4887 retmap
= zalloc(sizeof(*retmap
));
4891 memcpy(retmap
, map
, sizeof(*retmap
));
4895 static struct id_map
*find_mapped_hostid_entry(const struct list_head
*idmap
,
4896 unsigned id
, enum idtype idtype
)
4898 struct id_map
*retmap
= NULL
;
4901 list_for_each_entry(map
, idmap
, head
) {
4902 if (map
->idtype
!= idtype
)
4905 if (id
>= map
->hostid
&& id
< map
->hostid
+ map
->range
) {
4914 /* Allocate a new {g,u}id mapping for the given {g,u}id. Re-use an already
4915 * existing one or establish a new one.
4917 static struct id_map
*mapped_hostid_add(const struct lxc_conf
*conf
, uid_t id
,
4920 __do_free
struct id_map
*entry
= NULL
;
4922 struct id_map
*tmp
= NULL
;
4924 entry
= zalloc(sizeof(*entry
));
4928 /* Reuse existing mapping. */
4929 tmp
= find_mapped_hostid_entry(&conf
->id_map
, id
, type
);
4931 memcpy(entry
, tmp
, sizeof(*entry
));
4933 /* Find new mapping. */
4934 hostid_mapped
= find_unmapped_nsid(conf
, type
);
4935 if (hostid_mapped
< 0)
4936 return log_debug(NULL
, "Failed to find free mapping for id %d", id
);
4938 entry
->idtype
= type
;
4939 entry
->nsid
= hostid_mapped
;
4940 entry
->hostid
= (unsigned long)id
;
4944 return move_ptr(entry
);
4947 static int get_minimal_idmap(const struct lxc_conf
*conf
, uid_t
*resuid
,
4948 gid_t
*resgid
, struct list_head
*head_ret
)
4950 __do_free
struct id_map
*container_root_uid
= NULL
,
4951 *container_root_gid
= NULL
,
4952 *host_uid_map
= NULL
, *host_gid_map
= NULL
;
4954 uid_t nsuid
= (conf
->root_nsuid_map
!= NULL
) ? 0 : conf
->init_uid
;
4955 gid_t nsgid
= (conf
->root_nsgid_map
!= NULL
) ? 0 : conf
->init_gid
;
4957 /* Find container root mappings. */
4958 container_root_uid
= mapped_nsid_add(conf
, nsuid
, ID_TYPE_UID
);
4959 if (!container_root_uid
)
4960 return sysdebug("Failed to find mapping for namespace uid %d", 0);
4962 if (euid
>= container_root_uid
->hostid
&&
4963 euid
< (container_root_uid
->hostid
+ container_root_uid
->range
))
4964 host_uid_map
= move_ptr(container_root_uid
);
4966 container_root_gid
= mapped_nsid_add(conf
, nsgid
, ID_TYPE_GID
);
4967 if (!container_root_gid
)
4968 return sysdebug("Failed to find mapping for namespace gid %d", 0);
4970 if (egid
>= container_root_gid
->hostid
&&
4971 egid
< (container_root_gid
->hostid
+ container_root_gid
->range
))
4972 host_gid_map
= move_ptr(container_root_gid
);
4974 /* Check whether the {g,u}id of the user has a mapping. */
4976 host_uid_map
= mapped_hostid_add(conf
, euid
, ID_TYPE_UID
);
4978 return sysdebug("Failed to find mapping for uid %d", euid
);
4981 host_gid_map
= mapped_hostid_add(conf
, egid
, ID_TYPE_GID
);
4983 return sysdebug("Failed to find mapping for gid %d", egid
);
4985 /* idmap will now keep track of that memory. */
4986 list_add_tail(&host_uid_map
->head
, head_ret
);
4987 move_ptr(host_uid_map
);
4989 if (container_root_uid
) {
4990 /* idmap will now keep track of that memory. */
4991 list_add_tail(&container_root_uid
->head
, head_ret
);
4992 move_ptr(container_root_uid
);
4995 /* idmap will now keep track of that memory. */
4996 list_add_tail(&host_gid_map
->head
, head_ret
);
4997 move_ptr(host_gid_map
);
4999 if (container_root_gid
) {
5000 /* idmap will now keep track of that memory. */
5001 list_add_tail(&container_root_gid
->head
, head_ret
);
5002 move_ptr(container_root_gid
);
5005 TRACE("Allocated minimal idmapping for ns uid %d and ns gid %d", nsuid
, nsgid
);
5016 * Run a function in a new user namespace.
5017 * The caller's euid/egid will be mapped if it is not already.
5018 * Afaict, userns_exec_1() is only used to operate based on privileges for the
5019 * user's own {g,u}id on the host and for the container root's unmapped {g,u}id.
5020 * This means we require only to establish a mapping from:
5021 * - the container root {g,u}id as seen from the host > user's host {g,u}id
5022 * - the container root -> some sub{g,u}id
5023 * The former we add, if the user did not specify a mapping. The latter we
5024 * retrieve from the container's configured {g,u}id mappings as it must have been
5025 * there to start the container in the first place.
5027 int userns_exec_1(const struct lxc_conf
*conf
, int (*fn
)(void *), void *data
,
5028 const char *fn_name
)
5030 LIST_HEAD(minimal_idmap
);
5031 call_cleaner(__lxc_free_idmap
) struct list_head
*idmap
= &minimal_idmap
;
5032 int ret
= -1, status
= -1;
5034 struct userns_fn_data d
= {
5045 ret
= get_minimal_idmap(conf
, NULL
, NULL
, idmap
);
5047 return ret_errno(ENOENT
);
5049 ret
= pipe2(pipe_fds
, O_CLOEXEC
);
5053 d
.p
[0] = pipe_fds
[0];
5054 d
.p
[1] = pipe_fds
[1];
5056 /* Clone child in new user namespace. */
5057 pid
= lxc_raw_clone_cb(run_userns_fn
, &d
, CLONE_NEWUSER
, NULL
);
5059 ERROR("Failed to clone process in new user namespace");
5063 close_prot_errno_disarm(pipe_fds
[0]);
5065 if (lxc_log_trace()) {
5068 list_for_each_entry(map
, idmap
, head
)
5069 TRACE("Establishing %cid mapping for \"%d\" in new user namespace: nsuid %lu - hostid %lu - range %lu",
5070 (map
->idtype
== ID_TYPE_UID
) ? 'u' : 'g', pid
, map
->nsid
, map
->hostid
, map
->range
);
5073 /* Set up {g,u}id mapping for user namespace of child process. */
5074 ret
= lxc_map_ids(idmap
, pid
);
5076 ERROR("Error setting up {g,u}id mappings for child process \"%d\"", pid
);
5080 /* Tell child to proceed. */
5081 if (lxc_write_nointr(pipe_fds
[1], &c
, 1) != 1) {
5082 SYSERROR("Failed telling child process \"%d\" to proceed", pid
);
5087 close_prot_errno_disarm(pipe_fds
[0]);
5088 close_prot_errno_disarm(pipe_fds
[1]);
5090 /* Wait for child to finish. */
5092 status
= wait_for_pid(pid
);
5100 int userns_exec_minimal(const struct lxc_conf
*conf
,
5101 int (*fn_parent
)(void *), void *fn_parent_data
,
5102 int (*fn_child
)(void *), void *fn_child_data
)
5104 LIST_HEAD(minimal_idmap
);
5105 call_cleaner(__lxc_free_idmap
) struct list_head
*idmap
= &minimal_idmap
;
5106 uid_t resuid
= LXC_INVALID_UID
;
5107 gid_t resgid
= LXC_INVALID_GID
;
5113 if (!conf
|| !fn_child
)
5114 return ret_errno(EINVAL
);
5116 ret
= get_minimal_idmap(conf
, &resuid
, &resgid
, idmap
);
5118 return ret_errno(ENOENT
);
5120 ret
= socketpair(PF_LOCAL
, SOCK_STREAM
| SOCK_CLOEXEC
, 0, sock_fds
);
5126 SYSERROR("Failed to create new process");
5131 close_prot_errno_disarm(sock_fds
[1]);
5133 ret
= unshare(CLONE_NEWUSER
);
5135 SYSERROR("Failed to unshare new user namespace");
5136 _exit(EXIT_FAILURE
);
5139 ret
= lxc_write_nointr(sock_fds
[0], &c
, 1);
5141 _exit(EXIT_FAILURE
);
5143 ret
= lxc_read_nointr(sock_fds
[0], &c
, 1);
5145 _exit(EXIT_FAILURE
);
5147 close_prot_errno_disarm(sock_fds
[0]);
5149 if (!lxc_drop_groups() && errno
!= EPERM
)
5150 _exit(EXIT_FAILURE
);
5152 ret
= setresgid(resgid
, resgid
, resgid
);
5154 SYSERROR("Failed to setresgid(%d, %d, %d)",
5155 resgid
, resgid
, resgid
);
5156 _exit(EXIT_FAILURE
);
5159 ret
= setresuid(resuid
, resuid
, resuid
);
5161 SYSERROR("Failed to setresuid(%d, %d, %d)",
5162 resuid
, resuid
, resuid
);
5163 _exit(EXIT_FAILURE
);
5166 ret
= fn_child(fn_child_data
);
5168 SYSERROR("Running function in new user namespace failed");
5169 _exit(EXIT_FAILURE
);
5172 _exit(EXIT_SUCCESS
);
5175 close_prot_errno_disarm(sock_fds
[0]);
5177 if (lxc_log_trace()) {
5180 list_for_each_entry(map
, idmap
, head
)
5181 TRACE("Establishing %cid mapping for \"%d\" in new user namespace: nsuid %lu - hostid %lu - range %lu",
5182 (map
->idtype
== ID_TYPE_UID
) ? 'u' : 'g', pid
, map
->nsid
, map
->hostid
, map
->range
);
5185 ret
= lxc_read_nointr(sock_fds
[1], &c
, 1);
5187 SYSERROR("Failed waiting for child process %d\" to tell us to proceed", pid
);
5191 /* Set up {g,u}id mapping for user namespace of child process. */
5192 ret
= lxc_map_ids(idmap
, pid
);
5194 ERROR("Error setting up {g,u}id mappings for child process \"%d\"", pid
);
5198 /* Tell child to proceed. */
5199 ret
= lxc_write_nointr(sock_fds
[1], &c
, 1);
5201 SYSERROR("Failed telling child process \"%d\" to proceed", pid
);
5205 if (fn_parent
&& fn_parent(fn_parent_data
)) {
5206 SYSERROR("Running parent function failed");
5207 _exit(EXIT_FAILURE
);
5211 close_prot_errno_disarm(sock_fds
[0]);
5212 close_prot_errno_disarm(sock_fds
[1]);
5214 /* Wait for child to finish. */
5218 return wait_for_pid(pid
);
5221 int userns_exec_full(struct lxc_conf
*conf
, int (*fn
)(void *), void *data
,
5222 const char *fn_name
)
5224 LIST_HEAD(full_idmap
);
5227 struct id_map
*container_root_uid
= NULL
, *container_root_gid
= NULL
,
5228 *host_uid_map
= NULL
, *host_gid_map
= NULL
;
5233 struct userns_fn_data d
;
5238 ret
= pipe2(p
, O_CLOEXEC
);
5243 d
.fn_name
= fn_name
;
5248 /* Clone child in new user namespace. */
5249 pid
= lxc_clone(run_userns_fn
, &d
, CLONE_NEWUSER
, NULL
);
5251 ERROR("Failed to clone process in new user namespace");
5261 /* Find container root. */
5262 list_for_each_entry(map
, &conf
->id_map
, head
) {
5263 __do_free
struct id_map
*dup_map
= NULL
;
5265 dup_map
= memdup(map
, sizeof(struct id_map
));
5269 list_add_tail(&dup_map
->head
, &full_idmap
);
5272 if (map
->idtype
== ID_TYPE_UID
)
5273 if (euid
>= map
->hostid
&& euid
< map
->hostid
+ map
->range
)
5276 if (map
->idtype
== ID_TYPE_GID
)
5277 if (egid
>= map
->hostid
&& egid
< map
->hostid
+ map
->range
)
5283 if (map
->idtype
== ID_TYPE_UID
)
5284 if (container_root_uid
== NULL
)
5285 container_root_uid
= map
;
5287 if (map
->idtype
== ID_TYPE_GID
)
5288 if (container_root_gid
== NULL
)
5289 container_root_gid
= map
;
5292 if (!container_root_uid
|| !container_root_gid
) {
5293 ERROR("No mapping for container root found");
5297 /* Check whether the {g,u}id of the user has a mapping. */
5299 host_uid_map
= mapped_hostid_add(conf
, euid
, ID_TYPE_UID
);
5301 host_uid_map
= container_root_uid
;
5304 host_gid_map
= mapped_hostid_add(conf
, egid
, ID_TYPE_GID
);
5306 host_gid_map
= container_root_gid
;
5308 if (!host_uid_map
) {
5309 DEBUG("Failed to find mapping for uid %d", euid
);
5313 if (!host_gid_map
) {
5314 DEBUG("Failed to find mapping for gid %d", egid
);
5318 if (host_uid_map
&& (host_uid_map
!= container_root_uid
)) {
5319 /* idmap will now keep track of that memory. */
5320 list_add_tail(&host_uid_map
->head
, &full_idmap
);
5321 move_ptr(host_uid_map
);
5324 if (host_gid_map
&& (host_gid_map
!= container_root_gid
)) {
5325 /* idmap will now keep track of that memory. */
5326 list_add_tail(&host_gid_map
->head
, &full_idmap
);
5327 move_ptr(host_gid_map
);
5330 if (lxc_log_trace()) {
5331 list_for_each_entry(map
, &full_idmap
, head
) {
5332 TRACE("establishing %cid mapping for \"%d\" in new user namespace: nsuid %lu - hostid %lu - range %lu",
5333 (map
->idtype
== ID_TYPE_UID
) ? 'u' : 'g', pid
,
5334 map
->nsid
, map
->hostid
, map
->range
);
5338 /* Set up {g,u}id mapping for user namespace of child process. */
5339 ret
= lxc_map_ids(&full_idmap
, pid
);
5341 ERROR("error setting up {g,u}id mappings for child process \"%d\"", pid
);
5345 /* Tell child to proceed. */
5346 if (lxc_write_nointr(p
[1], &c
, 1) != 1) {
5347 SYSERROR("Failed telling child process \"%d\" to proceed", pid
);
5356 /* Wait for child to finish. */
5358 ret
= wait_for_pid(pid
);
5360 __lxc_free_idmap(&full_idmap
);
5362 if (host_uid_map
&& (host_uid_map
!= container_root_uid
))
5364 if (host_gid_map
&& (host_gid_map
!= container_root_gid
))
5370 static int add_idmap_entry(struct list_head
*idmap_list
, enum idtype idtype
,
5371 unsigned long nsid
, unsigned long hostid
,
5372 unsigned long range
)
5374 __do_free
struct id_map
*new_idmap
= NULL
;
5376 new_idmap
= zalloc(sizeof(*new_idmap
));
5378 return ret_errno(ENOMEM
);
5380 new_idmap
->idtype
= idtype
;
5381 new_idmap
->hostid
= hostid
;
5382 new_idmap
->nsid
= nsid
;
5383 new_idmap
->range
= range
;
5385 list_add_tail(&new_idmap
->head
, idmap_list
);
5386 move_ptr(new_idmap
);
5388 INFO("Adding id map: type %c nsid %lu hostid %lu range %lu",
5389 idtype
== ID_TYPE_UID
? 'u' : 'g', nsid
, hostid
, range
);
5393 int userns_exec_mapped_root(const char *path
, int path_fd
,
5394 const struct lxc_conf
*conf
)
5396 LIST_HEAD(idmap_list
);
5397 call_cleaner(__lxc_free_idmap
) struct list_head
*idmap
= &idmap_list
;
5398 __do_close
int fd
= -EBADF
;
5399 int target_fd
= -EBADF
;
5404 uid_t container_host_uid
, hostuid
;
5405 gid_t container_host_gid
, hostgid
;
5408 if (!conf
|| (!path
&& path_fd
< 0))
5409 return ret_errno(EINVAL
);
5414 container_host_uid
= get_mapped_rootid(conf
, ID_TYPE_UID
);
5415 if (!uid_valid(container_host_uid
))
5416 return log_error(-1, "No uid mapping for container root");
5418 container_host_gid
= get_mapped_rootid(conf
, ID_TYPE_GID
);
5419 if (!gid_valid(container_host_gid
))
5420 return log_error(-1, "No gid mapping for container root");
5423 fd
= open(path
, O_CLOEXEC
| O_NOCTTY
);
5425 return log_error_errno(-errno
, errno
, "Failed to open \"%s\"", path
);
5428 target_fd
= path_fd
;
5431 hostuid
= geteuid();
5432 /* We are root so chown directly. */
5434 ret
= fchown(target_fd
, container_host_uid
, container_host_gid
);
5436 return log_error_errno(-errno
, errno
,
5437 "Failed to fchown(%d(%s), %d, %d)",
5438 target_fd
, path
, container_host_uid
,
5439 container_host_gid
);
5440 return log_trace(0, "Chowned %d(%s) to uid %d and %d", target_fd
, path
,
5441 container_host_uid
, container_host_gid
);
5444 /* The container's root host id matches */
5445 if (container_host_uid
== hostuid
)
5446 return log_info(0, "Container root id is mapped to our uid");
5448 /* Get the current ids of our target. */
5449 ret
= fstat(target_fd
, &st
);
5451 return log_error_errno(-errno
, errno
, "Failed to stat \"%s\"", path
);
5453 hostgid
= getegid();
5454 if (st
.st_uid
== hostuid
&& mapped_hostid(st
.st_gid
, conf
, ID_TYPE_GID
) < 0) {
5455 ret
= fchown(target_fd
, -1, hostgid
);
5457 return log_error_errno(-errno
, errno
,
5458 "Failed to fchown(%d(%s), -1, %d)",
5459 target_fd
, path
, hostgid
);
5460 TRACE("Chowned %d(%s) to -1:%d", target_fd
, path
, hostgid
);
5463 /* "u:0:rootuid:1" */
5464 ret
= add_idmap_entry(idmap
, ID_TYPE_UID
, 0, container_host_uid
, 1);
5466 return log_error_errno(ret
, -ret
, "Failed to add idmap entry");
5468 /* "u:hostuid:hostuid:1" */
5469 ret
= add_idmap_entry(idmap
, ID_TYPE_UID
, hostuid
, hostuid
, 1);
5471 return log_error_errno(ret
, -ret
, "Failed to add idmap entry");
5473 /* "g:0:rootgid:1" */
5474 ret
= add_idmap_entry(idmap
, ID_TYPE_GID
, 0, container_host_gid
, 1);
5476 return log_error_errno(ret
, -ret
, "Failed to add idmap entry");
5478 /* "g:hostgid:hostgid:1" */
5479 ret
= add_idmap_entry(idmap
, ID_TYPE_GID
, hostgid
, hostgid
, 1);
5481 return log_error_errno(ret
, -ret
, "Failed to add idmap entry");
5483 if (hostgid
!= st
.st_gid
) {
5484 /* "g:pathgid:rootgid+pathgid:1" */
5485 ret
= add_idmap_entry(idmap
, ID_TYPE_GID
, st
.st_gid
,
5486 container_host_gid
+ (gid_t
)st
.st_gid
, 1);
5488 return log_error_errno(ret
, -ret
, "Failed to add idmap entry");
5491 ret
= socketpair(PF_LOCAL
, SOCK_STREAM
| SOCK_CLOEXEC
, 0, sock_fds
);
5497 SYSERROR("Failed to create new process");
5502 close_prot_errno_disarm(sock_fds
[1]);
5504 ret
= unshare(CLONE_NEWUSER
);
5506 SYSERROR("Failed to unshare new user namespace");
5507 _exit(EXIT_FAILURE
);
5510 ret
= lxc_write_nointr(sock_fds
[0], &c
, 1);
5512 _exit(EXIT_FAILURE
);
5514 ret
= lxc_read_nointr(sock_fds
[0], &c
, 1);
5516 _exit(EXIT_FAILURE
);
5518 close_prot_errno_disarm(sock_fds
[0]);
5520 if (!lxc_switch_uid_gid(0, 0))
5521 _exit(EXIT_FAILURE
);
5523 if (!lxc_drop_groups())
5524 _exit(EXIT_FAILURE
);
5526 ret
= fchown(target_fd
, 0, st
.st_gid
);
5528 SYSERROR("Failed to chown %d(%s) to 0:%d", target_fd
, path
, st
.st_gid
);
5529 _exit(EXIT_FAILURE
);
5532 TRACE("Chowned %d(%s) to 0:%d", target_fd
, path
, st
.st_gid
);
5533 _exit(EXIT_SUCCESS
);
5536 close_prot_errno_disarm(sock_fds
[0]);
5538 if (lxc_log_trace()) {
5541 list_for_each_entry(map
, idmap
, head
)
5542 TRACE("Establishing %cid mapping for \"%d\" in new user namespace: nsuid %lu - hostid %lu - range %lu",
5543 (map
->idtype
== ID_TYPE_UID
) ? 'u' : 'g', pid
, map
->nsid
, map
->hostid
, map
->range
);
5546 ret
= lxc_read_nointr(sock_fds
[1], &c
, 1);
5548 SYSERROR("Failed waiting for child process %d\" to tell us to proceed", pid
);
5552 /* Set up {g,u}id mapping for user namespace of child process. */
5553 ret
= lxc_map_ids(idmap
, pid
);
5555 ERROR("Error setting up {g,u}id mappings for child process \"%d\"", pid
);
5559 /* Tell child to proceed. */
5560 ret
= lxc_write_nointr(sock_fds
[1], &c
, 1);
5562 SYSERROR("Failed telling child process \"%d\" to proceed", pid
);
5567 close_prot_errno_disarm(sock_fds
[0]);
5568 close_prot_errno_disarm(sock_fds
[1]);
5570 /* Wait for child to finish. */
5574 return wait_for_pid(pid
);
5577 /* not thread-safe, do not use from api without first forking */
5578 static char *getuname(void)
5580 __do_free
char *buf
= NULL
;
5581 struct passwd pwent
;
5582 struct passwd
*pwentp
= NULL
;
5586 bufsize
= sysconf(_SC_GETPW_R_SIZE_MAX
);
5590 buf
= zalloc(bufsize
);
5594 ret
= getpwuid_r(geteuid(), &pwent
, buf
, bufsize
, &pwentp
);
5597 WARN("Could not find matched password record.");
5599 return log_error(NULL
, "Failed to get password record - %u", geteuid());
5602 return strdup(pwent
.pw_name
);
5605 /* not thread-safe, do not use from api without first forking */
5606 static char *getgname(void)
5608 __do_free
char *buf
= NULL
;
5610 struct group
*grentp
= NULL
;
5614 bufsize
= sysconf(_SC_GETGR_R_SIZE_MAX
);
5618 buf
= zalloc(bufsize
);
5622 ret
= getgrgid_r(getegid(), &grent
, buf
, bufsize
, &grentp
);
5625 WARN("Could not find matched group record");
5627 return log_error(NULL
, "Failed to get group record - %u", getegid());
5630 return strdup(grent
.gr_name
);
5633 /* not thread-safe, do not use from api without first forking */
5634 void suggest_default_idmap(void)
5636 __do_free
char *gname
= NULL
, *line
= NULL
, *uname
= NULL
;
5637 __do_fclose
FILE *subuid_f
= NULL
, *subgid_f
= NULL
;
5638 unsigned int uid
= 0, urange
= 0, gid
= 0, grange
= 0;
5649 subuid_f
= fopen(subuidfile
, "re");
5651 ERROR("Your system is not configured with subuids");
5655 while (getline(&line
, &len
, subuid_f
) != -1) {
5657 size_t no_newline
= 0;
5659 p
= strchr(line
, ':');
5667 if (!strequal(line
, uname
))
5670 p2
= strchr(p
, ':');
5677 no_newline
= strcspn(p2
, "\n");
5678 p2
[no_newline
] = '\0';
5680 if (lxc_safe_uint(p
, &uid
) < 0)
5681 WARN("Could not parse UID");
5682 if (lxc_safe_uint(p2
, &urange
) < 0)
5683 WARN("Could not parse UID range");
5686 subgid_f
= fopen(subgidfile
, "re");
5688 ERROR("Your system is not configured with subgids");
5692 while (getline(&line
, &len
, subgid_f
) != -1) {
5694 size_t no_newline
= 0;
5696 p
= strchr(line
, ':');
5704 if (!strequal(line
, uname
))
5707 p2
= strchr(p
, ':');
5714 no_newline
= strcspn(p2
, "\n");
5715 p2
[no_newline
] = '\0';
5717 if (lxc_safe_uint(p
, &gid
) < 0)
5718 WARN("Could not parse GID");
5719 if (lxc_safe_uint(p2
, &grange
) < 0)
5720 WARN("Could not parse GID range");
5723 if (!urange
|| !grange
) {
5724 ERROR("You do not have subuids or subgids allocated");
5725 ERROR("Unprivileged containers require subuids and subgids");
5729 ERROR("You must either run as root, or define uid mappings");
5730 ERROR("To pass uid mappings to lxc-create, you could create");
5731 ERROR("~/.config/lxc/default.conf:");
5732 ERROR("lxc.include = %s", LXC_DEFAULT_CONFIG
);
5733 ERROR("lxc.idmap = u 0 %u %u", uid
, urange
);
5734 ERROR("lxc.idmap = g 0 %u %u", gid
, grange
);
5737 /* Return the list of cgroup_settings sorted according to the following rules
5738 * 1. Put memory.limit_in_bytes before memory.memsw.limit_in_bytes
5740 void sort_cgroup_settings(struct lxc_conf
*conf
)
5742 struct lxc_cgroup
*cgroup
, *memsw_limit
, *ncgroup
;
5744 /* Iterate over the cgroup settings and copy them to the output list. */
5745 list_for_each_entry_safe(cgroup
, ncgroup
, &conf
->cgroup
, head
) {
5746 if (strequal(cgroup
->subsystem
, "memory.memsw.limit_in_bytes")) {
5747 /* Store the memsw_limit location */
5748 memsw_limit
= cgroup
;
5749 } else if (memsw_limit
&& strequal(cgroup
->subsystem
, "memory.limit_in_bytes")) {
5751 * lxc.cgroup.memory.memsw.limit_in_bytes is found
5752 * before lxc.cgroup.memory.limit_in_bytes, swap these
5755 list_swap(&memsw_limit
->head
, &cgroup
->head
);