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namespace.c
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namespace.c
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <linux/loop.h>
#include <sched.h>
#include <stdio.h>
#include <sys/mount.h>
#include <unistd.h>
#include <linux/fs.h>
#include "alloc-util.h"
#include "base-filesystem.h"
#include "dev-setup.h"
#include "fd-util.h"
#include "format-util.h"
#include "fs-util.h"
#include "label.h"
#include "list.h"
#include "loop-util.h"
#include "loopback-setup.h"
#include "mkdir.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "namespace-util.h"
#include "namespace.h"
#include "nulstr-util.h"
#include "path-util.h"
#include "selinux-util.h"
#include "socket-util.h"
#include "sort-util.h"
#include "stat-util.h"
#include "string-table.h"
#include "string-util.h"
#include "strv.h"
#include "tmpfile-util.h"
#include "umask-util.h"
#include "user-util.h"
#define DEV_MOUNT_OPTIONS (MS_NOSUID|MS_STRICTATIME|MS_NOEXEC)
typedef enum MountMode {
/* This is ordered by priority! */
INACCESSIBLE,
MOUNT_IMAGES,
BIND_MOUNT,
BIND_MOUNT_RECURSIVE,
PRIVATE_TMP,
PRIVATE_TMP_READONLY,
PRIVATE_DEV,
BIND_DEV,
EMPTY_DIR,
SYSFS,
PROCFS,
READONLY,
READWRITE,
TMPFS,
READWRITE_IMPLICIT, /* Should have the lowest priority. */
_MOUNT_MODE_MAX,
} MountMode;
typedef struct MountEntry {
const char *path_const; /* Memory allocated on stack or static */
MountMode mode:5;
bool ignore:1; /* Ignore if path does not exist? */
bool has_prefix:1; /* Already is prefixed by the root dir? */
bool read_only:1; /* Shall this mount point be read-only? */
bool nosuid:1; /* Shall set MS_NOSUID on the mount itself */
bool applied:1; /* Already applied */
char *path_malloc; /* Use this instead of 'path_const' if we had to allocate memory */
const char *source_const; /* The source path, for bind mounts or images */
char *source_malloc;
const char *options_const;/* Mount options for tmpfs */
char *options_malloc;
unsigned long flags; /* Mount flags used by EMPTY_DIR and TMPFS. Do not include MS_RDONLY here, but please use read_only. */
unsigned n_followed;
LIST_HEAD(MountOptions, image_options);
} MountEntry;
/* If MountAPIVFS= is used, let's mount /sys and /proc into the it, but only as a fallback if the user hasn't mounted
* something there already. These mounts are hence overridden by any other explicitly configured mounts. */
static const MountEntry apivfs_table[] = {
{ "/proc", PROCFS, false },
{ "/dev", BIND_DEV, false },
{ "/sys", SYSFS, false },
};
/* ProtectKernelTunables= option and the related filesystem APIs */
static const MountEntry protect_kernel_tunables_table[] = {
{ "/proc/acpi", READONLY, true },
{ "/proc/apm", READONLY, true }, /* Obsolete API, there's no point in permitting access to this, ever */
{ "/proc/asound", READONLY, true },
{ "/proc/bus", READONLY, true },
{ "/proc/fs", READONLY, true },
{ "/proc/irq", READONLY, true },
{ "/proc/kallsyms", INACCESSIBLE, true },
{ "/proc/kcore", INACCESSIBLE, true },
{ "/proc/latency_stats", READONLY, true },
{ "/proc/mtrr", READONLY, true },
{ "/proc/scsi", READONLY, true },
{ "/proc/sys", READONLY, true },
{ "/proc/sysrq-trigger", READONLY, true },
{ "/proc/timer_stats", READONLY, true },
{ "/sys", READONLY, false },
{ "/sys/fs/bpf", READONLY, true },
{ "/sys/fs/cgroup", READWRITE_IMPLICIT, false }, /* READONLY is set by ProtectControlGroups= option */
{ "/sys/fs/selinux", READWRITE_IMPLICIT, true },
{ "/sys/kernel/debug", READONLY, true },
{ "/sys/kernel/tracing", READONLY, true },
};
/* ProtectKernelModules= option */
static const MountEntry protect_kernel_modules_table[] = {
#if HAVE_SPLIT_USR
{ "/lib/modules", INACCESSIBLE, true },
#endif
{ "/usr/lib/modules", INACCESSIBLE, true },
};
/* ProtectKernelLogs= option */
static const MountEntry protect_kernel_logs_table[] = {
{ "/proc/kmsg", INACCESSIBLE, true },
{ "/dev/kmsg", INACCESSIBLE, true },
};
/*
* ProtectHome=read-only table, protect $HOME and $XDG_RUNTIME_DIR and rest of
* system should be protected by ProtectSystem=
*/
static const MountEntry protect_home_read_only_table[] = {
{ "/home", READONLY, true },
{ "/run/user", READONLY, true },
{ "/root", READONLY, true },
};
/* ProtectHome=tmpfs table */
static const MountEntry protect_home_tmpfs_table[] = {
{ "/home", TMPFS, true, .read_only = true, .options_const = "mode=0755" TMPFS_LIMITS_EMPTY_OR_ALMOST, .flags = MS_NODEV|MS_STRICTATIME },
{ "/run/user", TMPFS, true, .read_only = true, .options_const = "mode=0755" TMPFS_LIMITS_EMPTY_OR_ALMOST, .flags = MS_NODEV|MS_STRICTATIME },
{ "/root", TMPFS, true, .read_only = true, .options_const = "mode=0700" TMPFS_LIMITS_EMPTY_OR_ALMOST, .flags = MS_NODEV|MS_STRICTATIME },
};
/* ProtectHome=yes table */
static const MountEntry protect_home_yes_table[] = {
{ "/home", INACCESSIBLE, true },
{ "/run/user", INACCESSIBLE, true },
{ "/root", INACCESSIBLE, true },
};
/* ProtectSystem=yes table */
static const MountEntry protect_system_yes_table[] = {
{ "/usr", READONLY, false },
{ "/boot", READONLY, true },
{ "/efi", READONLY, true },
#if HAVE_SPLIT_USR
{ "/lib", READONLY, true },
{ "/lib64", READONLY, true },
{ "/bin", READONLY, true },
# if HAVE_SPLIT_BIN
{ "/sbin", READONLY, true },
# endif
#endif
};
/* ProtectSystem=full includes ProtectSystem=yes */
static const MountEntry protect_system_full_table[] = {
{ "/usr", READONLY, false },
{ "/boot", READONLY, true },
{ "/efi", READONLY, true },
{ "/etc", READONLY, false },
#if HAVE_SPLIT_USR
{ "/lib", READONLY, true },
{ "/lib64", READONLY, true },
{ "/bin", READONLY, true },
# if HAVE_SPLIT_BIN
{ "/sbin", READONLY, true },
# endif
#endif
};
/*
* ProtectSystem=strict table. In this strict mode, we mount everything
* read-only, except for /proc, /dev, /sys which are the kernel API VFS,
* which are left writable, but PrivateDevices= + ProtectKernelTunables=
* protect those, and these options should be fully orthogonal.
* (And of course /home and friends are also left writable, as ProtectHome=
* shall manage those, orthogonally).
*/
static const MountEntry protect_system_strict_table[] = {
{ "/", READONLY, false },
{ "/proc", READWRITE_IMPLICIT, false }, /* ProtectKernelTunables= */
{ "/sys", READWRITE_IMPLICIT, false }, /* ProtectKernelTunables= */
{ "/dev", READWRITE_IMPLICIT, false }, /* PrivateDevices= */
{ "/home", READWRITE_IMPLICIT, true }, /* ProtectHome= */
{ "/run/user", READWRITE_IMPLICIT, true }, /* ProtectHome= */
{ "/root", READWRITE_IMPLICIT, true }, /* ProtectHome= */
};
static const char * const mount_mode_table[_MOUNT_MODE_MAX] = {
[INACCESSIBLE] = "inaccessible",
[BIND_MOUNT] = "bind",
[BIND_MOUNT_RECURSIVE] = "rbind",
[PRIVATE_TMP] = "private-tmp",
[PRIVATE_DEV] = "private-dev",
[BIND_DEV] = "bind-dev",
[EMPTY_DIR] = "empty",
[SYSFS] = "sysfs",
[PROCFS] = "procfs",
[READONLY] = "read-only",
[READWRITE] = "read-write",
[TMPFS] = "tmpfs",
[MOUNT_IMAGES] = "mount-images",
[READWRITE_IMPLICIT] = "rw-implicit",
};
DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(mount_mode, MountMode);
static const char *mount_entry_path(const MountEntry *p) {
assert(p);
/* Returns the path of this bind mount. If the malloc()-allocated ->path_buffer field is set we return that,
* otherwise the stack/static ->path field is returned. */
return p->path_malloc ?: p->path_const;
}
static bool mount_entry_read_only(const MountEntry *p) {
assert(p);
return p->read_only || IN_SET(p->mode, READONLY, INACCESSIBLE, PRIVATE_TMP_READONLY);
}
static const char *mount_entry_source(const MountEntry *p) {
assert(p);
return p->source_malloc ?: p->source_const;
}
static const char *mount_entry_options(const MountEntry *p) {
assert(p);
return p->options_malloc ?: p->options_const;
}
static void mount_entry_done(MountEntry *p) {
assert(p);
p->path_malloc = mfree(p->path_malloc);
p->source_malloc = mfree(p->source_malloc);
p->options_malloc = mfree(p->options_malloc);
p->image_options = mount_options_free_all(p->image_options);
}
static int append_access_mounts(MountEntry **p, char **strv, MountMode mode, bool forcibly_require_prefix) {
char **i;
assert(p);
/* Adds a list of user-supplied READWRITE/READWRITE_IMPLICIT/READONLY/INACCESSIBLE entries */
STRV_FOREACH(i, strv) {
bool ignore = false, needs_prefix = false;
const char *e = *i;
/* Look for any prefixes */
if (startswith(e, "-")) {
e++;
ignore = true;
}
if (startswith(e, "+")) {
e++;
needs_prefix = true;
}
if (!path_is_absolute(e))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"Path is not absolute: %s", e);
*((*p)++) = (MountEntry) {
.path_const = e,
.mode = mode,
.ignore = ignore,
.has_prefix = !needs_prefix && !forcibly_require_prefix,
};
}
return 0;
}
static int append_empty_dir_mounts(MountEntry **p, char **strv) {
char **i;
assert(p);
/* Adds tmpfs mounts to provide readable but empty directories. This is primarily used to implement the
* "/private/" boundary directories for DynamicUser=1. */
STRV_FOREACH(i, strv) {
*((*p)++) = (MountEntry) {
.path_const = *i,
.mode = EMPTY_DIR,
.ignore = false,
.read_only = true,
.options_const = "mode=755" TMPFS_LIMITS_EMPTY_OR_ALMOST,
.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME,
};
}
return 0;
}
static int append_bind_mounts(MountEntry **p, const BindMount *binds, size_t n) {
size_t i;
assert(p);
for (i = 0; i < n; i++) {
const BindMount *b = binds + i;
*((*p)++) = (MountEntry) {
.path_const = b->destination,
.mode = b->recursive ? BIND_MOUNT_RECURSIVE : BIND_MOUNT,
.read_only = b->read_only,
.nosuid = b->nosuid,
.source_const = b->source,
.ignore = b->ignore_enoent,
};
}
return 0;
}
static int append_mount_images(MountEntry **p, const MountImage *mount_images, size_t n) {
assert(p);
for (size_t i = 0; i < n; i++) {
const MountImage *m = mount_images + i;
*((*p)++) = (MountEntry) {
.path_const = m->destination,
.mode = MOUNT_IMAGES,
.source_const = m->source,
.image_options = m->mount_options,
.ignore = m->ignore_enoent,
};
}
return 0;
}
static int append_tmpfs_mounts(MountEntry **p, const TemporaryFileSystem *tmpfs, size_t n) {
assert(p);
for (size_t i = 0; i < n; i++) {
const TemporaryFileSystem *t = tmpfs + i;
_cleanup_free_ char *o = NULL, *str = NULL;
unsigned long flags;
bool ro = false;
int r;
if (!path_is_absolute(t->path))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"Path is not absolute: %s",
t->path);
str = strjoin("mode=0755" NESTED_TMPFS_LIMITS ",", t->options);
if (!str)
return -ENOMEM;
r = mount_option_mangle(str, MS_NODEV|MS_STRICTATIME, &flags, &o);
if (r < 0)
return log_debug_errno(r, "Failed to parse mount option '%s': %m", str);
ro = flags & MS_RDONLY;
if (ro)
flags ^= MS_RDONLY;
*((*p)++) = (MountEntry) {
.path_const = t->path,
.mode = TMPFS,
.read_only = ro,
.options_malloc = TAKE_PTR(o),
.flags = flags,
};
}
return 0;
}
static int append_static_mounts(MountEntry **p, const MountEntry *mounts, size_t n, bool ignore_protect) {
size_t i;
assert(p);
assert(mounts);
/* Adds a list of static pre-defined entries */
for (i = 0; i < n; i++)
*((*p)++) = (MountEntry) {
.path_const = mount_entry_path(mounts+i),
.mode = mounts[i].mode,
.ignore = mounts[i].ignore || ignore_protect,
};
return 0;
}
static int append_protect_home(MountEntry **p, ProtectHome protect_home, bool ignore_protect) {
assert(p);
switch (protect_home) {
case PROTECT_HOME_NO:
return 0;
case PROTECT_HOME_READ_ONLY:
return append_static_mounts(p, protect_home_read_only_table, ELEMENTSOF(protect_home_read_only_table), ignore_protect);
case PROTECT_HOME_TMPFS:
return append_static_mounts(p, protect_home_tmpfs_table, ELEMENTSOF(protect_home_tmpfs_table), ignore_protect);
case PROTECT_HOME_YES:
return append_static_mounts(p, protect_home_yes_table, ELEMENTSOF(protect_home_yes_table), ignore_protect);
default:
assert_not_reached("Unexpected ProtectHome= value");
}
}
static int append_protect_system(MountEntry **p, ProtectSystem protect_system, bool ignore_protect) {
assert(p);
switch (protect_system) {
case PROTECT_SYSTEM_NO:
return 0;
case PROTECT_SYSTEM_STRICT:
return append_static_mounts(p, protect_system_strict_table, ELEMENTSOF(protect_system_strict_table), ignore_protect);
case PROTECT_SYSTEM_YES:
return append_static_mounts(p, protect_system_yes_table, ELEMENTSOF(protect_system_yes_table), ignore_protect);
case PROTECT_SYSTEM_FULL:
return append_static_mounts(p, protect_system_full_table, ELEMENTSOF(protect_system_full_table), ignore_protect);
default:
assert_not_reached("Unexpected ProtectSystem= value");
}
}
static int mount_path_compare(const MountEntry *a, const MountEntry *b) {
int d;
/* If the paths are not equal, then order prefixes first */
d = path_compare(mount_entry_path(a), mount_entry_path(b));
if (d != 0)
return d;
/* If the paths are equal, check the mode */
return CMP((int) a->mode, (int) b->mode);
}
static int prefix_where_needed(MountEntry *m, size_t n, const char *root_directory) {
size_t i;
/* Prefixes all paths in the bind mount table with the root directory if the entry needs that. */
for (i = 0; i < n; i++) {
char *s;
if (m[i].has_prefix)
continue;
s = path_join(root_directory, mount_entry_path(m+i));
if (!s)
return -ENOMEM;
free_and_replace(m[i].path_malloc, s);
m[i].has_prefix = true;
}
return 0;
}
static void drop_duplicates(MountEntry *m, size_t *n) {
MountEntry *f, *t, *previous;
assert(m);
assert(n);
/* Drops duplicate entries. Expects that the array is properly ordered already. */
for (f = m, t = m, previous = NULL; f < m + *n; f++) {
/* The first one wins (which is the one with the more restrictive mode), see mount_path_compare()
* above. Note that we only drop duplicates that haven't been mounted yet. */
if (previous &&
path_equal(mount_entry_path(f), mount_entry_path(previous)) &&
!f->applied && !previous->applied) {
log_debug("%s (%s) is duplicate.", mount_entry_path(f), mount_mode_to_string(f->mode));
previous->read_only = previous->read_only || mount_entry_read_only(f); /* Propagate the read-only flag to the remaining entry */
mount_entry_done(f);
continue;
}
*t = *f;
previous = t;
t++;
}
*n = t - m;
}
static void drop_inaccessible(MountEntry *m, size_t *n) {
MountEntry *f, *t;
const char *clear = NULL;
assert(m);
assert(n);
/* Drops all entries obstructed by another entry further up the tree. Expects that the array is properly
* ordered already. */
for (f = m, t = m; f < m + *n; f++) {
/* If we found a path set for INACCESSIBLE earlier, and this entry has it as prefix we should drop
* it, as inaccessible paths really should drop the entire subtree. */
if (clear && path_startswith(mount_entry_path(f), clear)) {
log_debug("%s is masked by %s.", mount_entry_path(f), clear);
mount_entry_done(f);
continue;
}
clear = f->mode == INACCESSIBLE ? mount_entry_path(f) : NULL;
*t = *f;
t++;
}
*n = t - m;
}
static void drop_nop(MountEntry *m, size_t *n) {
MountEntry *f, *t;
assert(m);
assert(n);
/* Drops all entries which have an immediate parent that has the same type, as they are redundant. Assumes the
* list is ordered by prefixes. */
for (f = m, t = m; f < m + *n; f++) {
/* Only suppress such subtrees for READONLY, READWRITE and READWRITE_IMPLICIT entries */
if (IN_SET(f->mode, READONLY, READWRITE, READWRITE_IMPLICIT)) {
MountEntry *p;
bool found = false;
/* Now let's find the first parent of the entry we are looking at. */
for (p = t-1; p >= m; p--) {
if (path_startswith(mount_entry_path(f), mount_entry_path(p))) {
found = true;
break;
}
}
/* We found it, let's see if it's the same mode, if so, we can drop this entry */
if (found && p->mode == f->mode) {
log_debug("%s (%s) is made redundant by %s (%s)",
mount_entry_path(f), mount_mode_to_string(f->mode),
mount_entry_path(p), mount_mode_to_string(p->mode));
mount_entry_done(f);
continue;
}
}
*t = *f;
t++;
}
*n = t - m;
}
static void drop_outside_root(const char *root_directory, MountEntry *m, size_t *n) {
MountEntry *f, *t;
assert(m);
assert(n);
/* Nothing to do */
if (!root_directory)
return;
/* Drops all mounts that are outside of the root directory. */
for (f = m, t = m; f < m + *n; f++) {
if (!path_startswith(mount_entry_path(f), root_directory)) {
log_debug("%s is outside of root directory.", mount_entry_path(f));
mount_entry_done(f);
continue;
}
*t = *f;
t++;
}
*n = t - m;
}
static int clone_device_node(
const char *d,
const char *temporary_mount,
bool *make_devnode) {
_cleanup_free_ char *sl = NULL;
const char *dn, *bn, *t;
struct stat st;
int r;
if (stat(d, &st) < 0) {
if (errno == ENOENT) {
log_debug_errno(errno, "Device node '%s' to clone does not exist, ignoring.", d);
return -ENXIO;
}
return log_debug_errno(errno, "Failed to stat() device node '%s' to clone, ignoring: %m", d);
}
if (!S_ISBLK(st.st_mode) &&
!S_ISCHR(st.st_mode))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"Device node '%s' to clone is not a device node, ignoring.",
d);
dn = strjoina(temporary_mount, d);
/* First, try to create device node properly */
if (*make_devnode) {
mac_selinux_create_file_prepare(d, st.st_mode);
r = mknod(dn, st.st_mode, st.st_rdev);
mac_selinux_create_file_clear();
if (r >= 0)
goto add_symlink;
if (errno != EPERM)
return log_debug_errno(errno, "mknod failed for %s: %m", d);
/* This didn't work, let's not try this again for the next iterations. */
*make_devnode = false;
}
/* We're about to fall back to bind-mounting the device
* node. So create a dummy bind-mount target.
* Do not prepare device-node SELinux label (see issue 13762) */
r = mknod(dn, S_IFREG, 0);
if (r < 0 && errno != EEXIST)
return log_debug_errno(errno, "mknod() fallback failed for '%s': %m", d);
/* Fallback to bind-mounting: The assumption here is that all used device nodes carry standard
* properties. Specifically, the devices nodes we bind-mount should either be owned by root:root or
* root:tty (e.g. /dev/tty, /dev/ptmx) and should not carry ACLs. */
r = mount_nofollow_verbose(LOG_DEBUG, d, dn, NULL, MS_BIND, NULL);
if (r < 0)
return r;
add_symlink:
bn = path_startswith(d, "/dev/");
if (!bn)
return 0;
/* Create symlinks like /dev/char/1:9 → ../urandom */
if (asprintf(&sl, "%s/dev/%s/%u:%u",
temporary_mount,
S_ISCHR(st.st_mode) ? "char" : "block",
major(st.st_rdev), minor(st.st_rdev)) < 0)
return log_oom();
(void) mkdir_parents(sl, 0755);
t = strjoina("../", bn);
if (symlink(t, sl) < 0)
log_debug_errno(errno, "Failed to symlink '%s' to '%s', ignoring: %m", t, sl);
return 0;
}
static int mount_private_dev(MountEntry *m) {
static const char devnodes[] =
"/dev/null\0"
"/dev/zero\0"
"/dev/full\0"
"/dev/random\0"
"/dev/urandom\0"
"/dev/tty\0";
char temporary_mount[] = "/tmp/namespace-dev-XXXXXX";
const char *d, *dev = NULL, *devpts = NULL, *devshm = NULL, *devhugepages = NULL, *devmqueue = NULL, *devlog = NULL, *devptmx = NULL;
bool can_mknod = true;
_cleanup_umask_ mode_t u;
int r;
assert(m);
u = umask(0000);
if (!mkdtemp(temporary_mount))
return log_debug_errno(errno, "Failed to create temporary directory '%s': %m", temporary_mount);
dev = strjoina(temporary_mount, "/dev");
(void) mkdir(dev, 0755);
r = mount_nofollow_verbose(LOG_DEBUG, "tmpfs", dev, "tmpfs", DEV_MOUNT_OPTIONS, "mode=755" TMPFS_LIMITS_DEV);
if (r < 0)
goto fail;
r = label_fix_container(dev, "/dev", 0);
if (r < 0) {
log_debug_errno(errno, "Failed to fix label of '%s' as /dev: %m", dev);
goto fail;
}
devpts = strjoina(temporary_mount, "/dev/pts");
(void) mkdir(devpts, 0755);
r = mount_nofollow_verbose(LOG_DEBUG, "/dev/pts", devpts, NULL, MS_BIND, NULL);
if (r < 0)
goto fail;
/* /dev/ptmx can either be a device node or a symlink to /dev/pts/ptmx.
* When /dev/ptmx a device node, /dev/pts/ptmx has 000 permissions making it inaccessible.
* Thus, in that case make a clone.
* In nspawn and other containers it will be a symlink, in that case make it a symlink. */
r = is_symlink("/dev/ptmx");
if (r < 0) {
log_debug_errno(r, "Failed to detect whether /dev/ptmx is a symlink or not: %m");
goto fail;
} else if (r > 0) {
devptmx = strjoina(temporary_mount, "/dev/ptmx");
if (symlink("pts/ptmx", devptmx) < 0) {
r = log_debug_errno(errno, "Failed to create a symlink '%s' to pts/ptmx: %m", devptmx);
goto fail;
}
} else {
r = clone_device_node("/dev/ptmx", temporary_mount, &can_mknod);
if (r < 0)
goto fail;
}
devshm = strjoina(temporary_mount, "/dev/shm");
(void) mkdir(devshm, 0755);
r = mount_nofollow_verbose(LOG_DEBUG, "/dev/shm", devshm, NULL, MS_BIND, NULL);
if (r < 0)
goto fail;
devmqueue = strjoina(temporary_mount, "/dev/mqueue");
(void) mkdir(devmqueue, 0755);
(void) mount_nofollow_verbose(LOG_DEBUG, "/dev/mqueue", devmqueue, NULL, MS_BIND, NULL);
devhugepages = strjoina(temporary_mount, "/dev/hugepages");
(void) mkdir(devhugepages, 0755);
(void) mount_nofollow_verbose(LOG_DEBUG, "/dev/hugepages", devhugepages, NULL, MS_BIND, NULL);
devlog = strjoina(temporary_mount, "/dev/log");
if (symlink("/run/systemd/journal/dev-log", devlog) < 0)
log_debug_errno(errno, "Failed to create a symlink '%s' to /run/systemd/journal/dev-log, ignoring: %m", devlog);
NULSTR_FOREACH(d, devnodes) {
r = clone_device_node(d, temporary_mount, &can_mknod);
/* ENXIO means the *source* is not a device file, skip creation in that case */
if (r < 0 && r != -ENXIO)
goto fail;
}
r = dev_setup(temporary_mount, UID_INVALID, GID_INVALID);
if (r < 0)
log_debug_errno(r, "Failed to set up basic device tree at '%s', ignoring: %m", temporary_mount);
/* Create the /dev directory if missing. It is more likely to be
* missing when the service is started with RootDirectory. This is
* consistent with mount units creating the mount points when missing.
*/
(void) mkdir_p_label(mount_entry_path(m), 0755);
/* Unmount everything in old /dev */
r = umount_recursive(mount_entry_path(m), 0);
if (r < 0)
log_debug_errno(r, "Failed to unmount directories below '%s', ignoring: %m", mount_entry_path(m));
r = mount_nofollow_verbose(LOG_DEBUG, dev, mount_entry_path(m), NULL, MS_MOVE, NULL);
if (r < 0)
goto fail;
(void) rmdir(dev);
(void) rmdir(temporary_mount);
return 0;
fail:
if (devpts)
(void) umount_verbose(LOG_DEBUG, devpts, UMOUNT_NOFOLLOW);
if (devshm)
(void) umount_verbose(LOG_DEBUG, devshm, UMOUNT_NOFOLLOW);
if (devhugepages)
(void) umount_verbose(LOG_DEBUG, devhugepages, UMOUNT_NOFOLLOW);
if (devmqueue)
(void) umount_verbose(LOG_DEBUG, devmqueue, UMOUNT_NOFOLLOW);
(void) umount_verbose(LOG_DEBUG, dev, UMOUNT_NOFOLLOW);
(void) rmdir(dev);
(void) rmdir(temporary_mount);
return r;
}
static int mount_bind_dev(const MountEntry *m) {
int r;
assert(m);
/* Implements the little brother of mount_private_dev(): simply bind mounts the host's /dev into the service's
* /dev. This is only used when RootDirectory= is set. */
(void) mkdir_p_label(mount_entry_path(m), 0755);
r = path_is_mount_point(mount_entry_path(m), NULL, 0);
if (r < 0)
return log_debug_errno(r, "Unable to determine whether /dev is already mounted: %m");
if (r > 0) /* make this a NOP if /dev is already a mount point */
return 0;
r = mount_nofollow_verbose(LOG_DEBUG, "/dev", mount_entry_path(m), NULL, MS_BIND|MS_REC, NULL);
if (r < 0)
return r;
return 1;
}
static int mount_sysfs(const MountEntry *m) {
int r;
assert(m);
(void) mkdir_p_label(mount_entry_path(m), 0755);
r = path_is_mount_point(mount_entry_path(m), NULL, 0);
if (r < 0)
return log_debug_errno(r, "Unable to determine whether /sys is already mounted: %m");
if (r > 0) /* make this a NOP if /sys is already a mount point */
return 0;
/* Bind mount the host's version so that we get all child mounts of it, too. */
r = mount_nofollow_verbose(LOG_DEBUG, "/sys", mount_entry_path(m), NULL, MS_BIND|MS_REC, NULL);
if (r < 0)
return r;
return 1;
}
static int mount_procfs(const MountEntry *m, const NamespaceInfo *ns_info) {
const char *entry_path;
int r;
assert(m);
assert(ns_info);
entry_path = mount_entry_path(m);
/* Mount a new instance, so that we get the one that matches our user namespace, if we are running in
* one. i.e we don't reuse existing mounts here under any condition, we want a new instance owned by
* our user namespace and with our hidepid= settings applied. Hence, let's get rid of everything
* mounted on /proc/ first. */
(void) mkdir_p_label(entry_path, 0755);
(void) umount_recursive(entry_path, 0);
if (ns_info->protect_proc != PROTECT_PROC_DEFAULT ||
ns_info->proc_subset != PROC_SUBSET_ALL) {
_cleanup_free_ char *opts = NULL;
/* Starting with kernel 5.8 procfs' hidepid= logic is truly per-instance (previously it
* pretended to be per-instance but actually was per-namespace), hence let's make use of it
* if requested. To make sure this logic succeeds only on kernels where hidepid= is
* per-instance, we'll exclusively use the textual value for hidepid=, since support was
* added in the same commit: if it's supported it is thus also per-instance. */
opts = strjoin("hidepid=",
ns_info->protect_proc == PROTECT_PROC_DEFAULT ? "off" :
protect_proc_to_string(ns_info->protect_proc),
ns_info->proc_subset == PROC_SUBSET_PID ? ",subset=pid" : "");
if (!opts)
return -ENOMEM;
r = mount_nofollow_verbose(LOG_DEBUG, "proc", entry_path, "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, opts);
if (r < 0) {
if (r != -EINVAL)
return r;
/* If this failed with EINVAL then this likely means the textual hidepid= stuff is
* not supported by the kernel, and thus the per-instance hidepid= neither, which
* means we really don't want to use it, since it would affect our host's /proc
* mount. Hence let's gracefully fallback to a classic, unrestricted version. */
} else
return 1;
}
r = mount_nofollow_verbose(LOG_DEBUG, "proc", entry_path, "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL);
if (r < 0)
return r;
return 1;
}
static int mount_tmpfs(const MountEntry *m) {
const char *entry_path, *inner_path;
int r;
assert(m);
entry_path = mount_entry_path(m);
inner_path = m->path_const;
/* First, get rid of everything that is below if there is anything. Then, overmount with our new tmpfs */
(void) mkdir_p_label(entry_path, 0755);
(void) umount_recursive(entry_path, 0);
r = mount_nofollow_verbose(LOG_DEBUG, "tmpfs", entry_path, "tmpfs", m->flags, mount_entry_options(m));
if (r < 0)
return r;
r = label_fix_container(entry_path, inner_path, 0);
if (r < 0)
return log_debug_errno(r, "Failed to fix label of '%s' as '%s': %m", entry_path, inner_path);
return 1;
}
static int mount_images(const MountEntry *m) {
_cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
_cleanup_(decrypted_image_unrefp) DecryptedImage *decrypted_image = NULL;
_cleanup_(dissected_image_unrefp) DissectedImage *dissected_image = NULL;
_cleanup_(verity_settings_done) VeritySettings verity = VERITY_SETTINGS_DEFAULT;
DissectImageFlags dissect_image_flags;
int r;
assert(m);
r = verity_settings_load(&verity, mount_entry_source(m), NULL, NULL);
if (r < 0)
return log_debug_errno(r, "Failed to load root hash: %m");
dissect_image_flags =
(m->read_only ? DISSECT_IMAGE_READ_ONLY : 0) |
(verity.data_path ? DISSECT_IMAGE_NO_PARTITION_TABLE : 0);
r = loop_device_make_by_path(
mount_entry_source(m),
m->read_only ? O_RDONLY : -1 /* < 0 means writable if possible, read-only as fallback */,
verity.data_path ? 0 : LO_FLAGS_PARTSCAN,
&loop_device);
if (r < 0)
return log_debug_errno(r, "Failed to create loop device for image: %m");
r = dissect_image(
loop_device->fd,
&verity,
m->image_options,
dissect_image_flags,
&dissected_image);
/* No partition table? Might be a single-filesystem image, try again */
if (!verity.data_path && r == -ENOPKG)
r = dissect_image(
loop_device->fd,
&verity,
m->image_options,
dissect_image_flags|DISSECT_IMAGE_NO_PARTITION_TABLE,
&dissected_image);
if (r < 0)
return log_debug_errno(r, "Failed to dissect image: %m");
r = dissected_image_decrypt(
dissected_image,
NULL,
&verity,
dissect_image_flags,
&decrypted_image);
if (r < 0)
return log_debug_errno(r, "Failed to decrypt dissected image: %m");
r = mkdir_p_label(mount_entry_path(m), 0755);
if (r < 0)
return log_debug_errno(r, "Failed to create destination directory %s: %m", mount_entry_path(m));
r = umount_recursive(mount_entry_path(m), 0);
if (r < 0)
return log_debug_errno(r, "Failed to umount under destination directory %s: %m", mount_entry_path(m));
r = dissected_image_mount(dissected_image, mount_entry_path(m), UID_INVALID, dissect_image_flags);
if (r == -ENOENT && m->ignore)