diff options
Diffstat (limited to 'src/core/namespace.c')
| -rw-r--r-- | src/core/namespace.c | 1043 |
1 files changed, 0 insertions, 1043 deletions
diff --git a/src/core/namespace.c b/src/core/namespace.c deleted file mode 100644 index 1195e9a854..0000000000 --- a/src/core/namespace.c +++ /dev/null @@ -1,1043 +0,0 @@ -/*** - This file is part of systemd. - - Copyright 2010 Lennart Poettering - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. -***/ - -#include <errno.h> -#include <sched.h> -#include <stdio.h> -#include <string.h> -#include <sys/mount.h> -#include <sys/stat.h> -#include <unistd.h> -#include <linux/fs.h> - -#include "alloc-util.h" -#include "dev-setup.h" -#include "fd-util.h" -#include "fs-util.h" -#include "loopback-setup.h" -#include "missing.h" -#include "mkdir.h" -#include "mount-util.h" -#include "namespace.h" -#include "path-util.h" -#include "selinux-util.h" -#include "socket-util.h" -#include "string-table.h" -#include "string-util.h" -#include "strv.h" -#include "umask-util.h" -#include "user-util.h" -#include "util.h" - -#define DEV_MOUNT_OPTIONS (MS_NOSUID|MS_STRICTATIME|MS_NOEXEC) - -typedef enum MountMode { - /* This is ordered by priority! */ - INACCESSIBLE, - READONLY, - PRIVATE_TMP, - PRIVATE_VAR_TMP, - PRIVATE_DEV, - READWRITE, -} MountMode; - -typedef struct BindMount { - const char *path; /* stack memory, doesn't need to be freed explicitly */ - char *chased; /* malloc()ed memory, needs to be freed */ - MountMode mode; - bool ignore; /* Ignore if path does not exist */ -} BindMount; - -typedef struct TargetMount { - const char *path; - MountMode mode; - bool ignore; /* Ignore if path does not exist */ -} TargetMount; - -/* - * The following Protect tables are to protect paths and mark some of them - * READONLY, in case a path is covered by an option from another table, then - * it is marked READWRITE in the current one, and the more restrictive mode is - * applied from that other table. This way all options can be combined in a - * safe and comprehensible way for users. - */ - -/* ProtectKernelTunables= option and the related filesystem APIs */ -static const TargetMount protect_kernel_tunables_table[] = { - { "/proc/sys", READONLY, false }, - { "/proc/sysrq-trigger", READONLY, true }, - { "/proc/latency_stats", READONLY, true }, - { "/proc/mtrr", READONLY, true }, - { "/proc/apm", READONLY, true }, - { "/proc/acpi", READONLY, true }, - { "/proc/timer_stats", READONLY, true }, - { "/proc/asound", READONLY, true }, - { "/proc/bus", READONLY, true }, - { "/proc/fs", READONLY, true }, - { "/proc/irq", READONLY, true }, - { "/sys", READONLY, false }, - { "/sys/kernel/debug", READONLY, true }, - { "/sys/kernel/tracing", READONLY, true }, - { "/sys/fs/cgroup", READWRITE, false }, /* READONLY is set by ProtectControlGroups= option */ -}; - -/* ProtectKernelModules= option */ -static const TargetMount protect_kernel_modules_table[] = { -#ifdef HAVE_SPLIT_USR - { "/lib/modules", INACCESSIBLE, true }, -#endif - { "/usr/lib/modules", INACCESSIBLE, true }, -}; - -/* - * ProtectHome=read-only table, protect $HOME and $XDG_RUNTIME_DIR and rest of - * system should be protected by ProtectSystem= - */ -static const TargetMount protect_home_read_only_table[] = { - { "/home", READONLY, true }, - { "/run/user", READONLY, true }, - { "/root", READONLY, true }, -}; - -/* ProtectHome=yes table */ -static const TargetMount protect_home_yes_table[] = { - { "/home", INACCESSIBLE, true }, - { "/run/user", INACCESSIBLE, true }, - { "/root", INACCESSIBLE, true }, -}; - -/* ProtectSystem=yes table */ -static const TargetMount protect_system_yes_table[] = { - { "/usr", READONLY, false }, - { "/boot", READONLY, true }, - { "/efi", READONLY, true }, -}; - -/* ProtectSystem=full includes ProtectSystem=yes */ -static const TargetMount protect_system_full_table[] = { - { "/usr", READONLY, false }, - { "/boot", READONLY, true }, - { "/efi", READONLY, true }, - { "/etc", READONLY, false }, -}; - -/* - * 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 TargetMount protect_system_strict_table[] = { - { "/", READONLY, false }, - { "/proc", READWRITE, false }, /* ProtectKernelTunables= */ - { "/sys", READWRITE, false }, /* ProtectKernelTunables= */ - { "/dev", READWRITE, false }, /* PrivateDevices= */ - { "/home", READWRITE, true }, /* ProtectHome= */ - { "/run/user", READWRITE, true }, /* ProtectHome= */ - { "/root", READWRITE, true }, /* ProtectHome= */ -}; - -static void set_bind_mount(BindMount **p, const char *path, MountMode mode, bool ignore) { - (*p)->path = path; - (*p)->mode = mode; - (*p)->ignore = ignore; -} - -static int append_mounts(BindMount **p, char **strv, MountMode mode) { - char **i; - - assert(p); - - STRV_FOREACH(i, strv) { - bool ignore = false; - - if (IN_SET(mode, INACCESSIBLE, READONLY, READWRITE) && startswith(*i, "-")) { - (*i)++; - ignore = true; - } - - if (!path_is_absolute(*i)) - return -EINVAL; - - set_bind_mount(p, *i, mode, ignore); - (*p)++; - } - - return 0; -} - -static int append_target_mounts(BindMount **p, const char *root_directory, const TargetMount *mounts, const size_t size) { - unsigned i; - - assert(p); - assert(mounts); - - for (i = 0; i < size; i++) { - /* - * Here we assume that the ignore field is set during - * declaration we do not support "-" at the beginning. - */ - const TargetMount *m = &mounts[i]; - const char *path = prefix_roota(root_directory, m->path); - - if (!path_is_absolute(path)) - return -EINVAL; - - set_bind_mount(p, path, m->mode, m->ignore); - (*p)++; - } - - return 0; -} - -static int append_protect_kernel_tunables(BindMount **p, const char *root_directory) { - assert(p); - - return append_target_mounts(p, root_directory, protect_kernel_tunables_table, - ELEMENTSOF(protect_kernel_tunables_table)); -} - -static int append_protect_kernel_modules(BindMount **p, const char *root_directory) { - assert(p); - - return append_target_mounts(p, root_directory, protect_kernel_modules_table, - ELEMENTSOF(protect_kernel_modules_table)); -} - -static int append_protect_home(BindMount **p, const char *root_directory, ProtectHome protect_home) { - int r = 0; - - assert(p); - - if (protect_home == PROTECT_HOME_NO) - return 0; - - switch (protect_home) { - case PROTECT_HOME_READ_ONLY: - r = append_target_mounts(p, root_directory, protect_home_read_only_table, - ELEMENTSOF(protect_home_read_only_table)); - break; - case PROTECT_HOME_YES: - r = append_target_mounts(p, root_directory, protect_home_yes_table, - ELEMENTSOF(protect_home_yes_table)); - break; - default: - r = -EINVAL; - break; - } - - return r; -} - -static int append_protect_system(BindMount **p, const char *root_directory, ProtectSystem protect_system) { - int r = 0; - - assert(p); - - if (protect_system == PROTECT_SYSTEM_NO) - return 0; - - switch (protect_system) { - case PROTECT_SYSTEM_STRICT: - r = append_target_mounts(p, root_directory, protect_system_strict_table, - ELEMENTSOF(protect_system_strict_table)); - break; - case PROTECT_SYSTEM_YES: - r = append_target_mounts(p, root_directory, protect_system_yes_table, - ELEMENTSOF(protect_system_yes_table)); - break; - case PROTECT_SYSTEM_FULL: - r = append_target_mounts(p, root_directory, protect_system_full_table, - ELEMENTSOF(protect_system_full_table)); - break; - default: - r = -EINVAL; - break; - } - - return r; -} - -static int mount_path_compare(const void *a, const void *b) { - const BindMount *p = a, *q = b; - int d; - - /* If the paths are not equal, then order prefixes first */ - d = path_compare(p->path, q->path); - if (d != 0) - return d; - - /* If the paths are equal, check the mode */ - if (p->mode < q->mode) - return -1; - - if (p->mode > q->mode) - return 1; - - return 0; -} - -static void drop_duplicates(BindMount *m, unsigned *n) { - BindMount *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. */ - if (previous && path_equal(f->path, previous->path)) { - log_debug("%s is duplicate.", f->path); - continue; - } - - *t = *f; - previous = t; - t++; - } - - *n = t - m; -} - -static void drop_inaccessible(BindMount *m, unsigned *n) { - BindMount *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(f->path, clear)) { - log_debug("%s is masked by %s.", f->path, clear); - continue; - } - - clear = f->mode == INACCESSIBLE ? f->path : NULL; - - *t = *f; - t++; - } - - *n = t - m; -} - -static void drop_nop(BindMount *m, unsigned *n) { - BindMount *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 and READWRITE entries */ - if (IN_SET(f->mode, READONLY, READWRITE)) { - BindMount *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(f->path, p->path)) { - 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 is redundant by %s", f->path, p->path); - continue; - } - } - - *t = *f; - t++; - } - - *n = t - m; -} - -static void drop_outside_root(const char *root_directory, BindMount *m, unsigned *n) { - BindMount *f, *t; - - assert(m); - assert(n); - - 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(f->path, root_directory)) { - log_debug("%s is outside of root directory.", f->path); - continue; - } - - *t = *f; - t++; - } - - *n = t - m; -} - -static int mount_dev(BindMount *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; - _cleanup_umask_ mode_t u; - int r; - - assert(m); - - u = umask(0000); - - if (!mkdtemp(temporary_mount)) - return -errno; - - dev = strjoina(temporary_mount, "/dev"); - (void) mkdir(dev, 0755); - if (mount("tmpfs", dev, "tmpfs", DEV_MOUNT_OPTIONS, "mode=755") < 0) { - r = -errno; - goto fail; - } - - devpts = strjoina(temporary_mount, "/dev/pts"); - (void) mkdir(devpts, 0755); - if (mount("/dev/pts", devpts, NULL, MS_BIND, NULL) < 0) { - r = -errno; - goto fail; - } - - devptmx = strjoina(temporary_mount, "/dev/ptmx"); - if (symlink("pts/ptmx", devptmx) < 0) { - r = -errno; - goto fail; - } - - devshm = strjoina(temporary_mount, "/dev/shm"); - (void) mkdir(devshm, 01777); - r = mount("/dev/shm", devshm, NULL, MS_BIND, NULL); - if (r < 0) { - r = -errno; - goto fail; - } - - devmqueue = strjoina(temporary_mount, "/dev/mqueue"); - (void) mkdir(devmqueue, 0755); - (void) mount("/dev/mqueue", devmqueue, NULL, MS_BIND, NULL); - - devhugepages = strjoina(temporary_mount, "/dev/hugepages"); - (void) mkdir(devhugepages, 0755); - (void) mount("/dev/hugepages", devhugepages, NULL, MS_BIND, NULL); - - devlog = strjoina(temporary_mount, "/dev/log"); - (void) symlink("/run/systemd/journal/dev-log", devlog); - - NULSTR_FOREACH(d, devnodes) { - _cleanup_free_ char *dn = NULL; - struct stat st; - - r = stat(d, &st); - if (r < 0) { - - if (errno == ENOENT) - continue; - - r = -errno; - goto fail; - } - - if (!S_ISBLK(st.st_mode) && - !S_ISCHR(st.st_mode)) { - r = -EINVAL; - goto fail; - } - - if (st.st_rdev == 0) - continue; - - dn = strappend(temporary_mount, d); - if (!dn) { - r = -ENOMEM; - goto fail; - } - - 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) { - r = -errno; - goto fail; - } - } - - dev_setup(temporary_mount, UID_INVALID, GID_INVALID); - - /* 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(m->path, 0755); - - /* Unmount everything in old /dev */ - umount_recursive(m->path, 0); - if (mount(dev, m->path, NULL, MS_MOVE, NULL) < 0) { - r = -errno; - goto fail; - } - - rmdir(dev); - rmdir(temporary_mount); - - return 0; - -fail: - if (devpts) - umount(devpts); - - if (devshm) - umount(devshm); - - if (devhugepages) - umount(devhugepages); - - if (devmqueue) - umount(devmqueue); - - umount(dev); - rmdir(dev); - rmdir(temporary_mount); - - return r; -} - -static int apply_mount( - BindMount *m, - const char *tmp_dir, - const char *var_tmp_dir) { - - const char *what; - int r; - - assert(m); - - log_debug("Applying namespace mount on %s", m->path); - - switch (m->mode) { - - case INACCESSIBLE: { - struct stat target; - - /* First, get rid of everything that is below if there - * is anything... Then, overmount it with an - * inaccessible path. */ - (void) umount_recursive(m->path, 0); - - if (lstat(m->path, &target) < 0) - return log_debug_errno(errno, "Failed to lstat() %s to determine what to mount over it: %m", m->path); - - what = mode_to_inaccessible_node(target.st_mode); - if (!what) { - log_debug("File type not supported for inaccessible mounts. Note that symlinks are not allowed"); - return -ELOOP; - } - break; - } - - case READONLY: - case READWRITE: - - r = path_is_mount_point(m->path, 0); - if (r < 0) - return log_debug_errno(r, "Failed to determine whether %s is already a mount point: %m", m->path); - if (r > 0) /* Nothing to do here, it is already a mount. We just later toggle the MS_RDONLY bit for the mount point if needed. */ - return 0; - - /* This isn't a mount point yet, let's make it one. */ - what = m->path; - break; - - case PRIVATE_TMP: - what = tmp_dir; - break; - - case PRIVATE_VAR_TMP: - what = var_tmp_dir; - break; - - case PRIVATE_DEV: - return mount_dev(m); - - default: - assert_not_reached("Unknown mode"); - } - - assert(what); - - if (mount(what, m->path, NULL, MS_BIND|MS_REC, NULL) < 0) - return log_debug_errno(errno, "Failed to mount %s to %s: %m", what, m->path); - - log_debug("Successfully mounted %s to %s", what, m->path); - return 0; -} - -static int make_read_only(BindMount *m, char **blacklist) { - int r = 0; - - assert(m); - - if (IN_SET(m->mode, INACCESSIBLE, READONLY)) - r = bind_remount_recursive(m->path, true, blacklist); - else if (m->mode == PRIVATE_DEV) { /* Can be readonly but the submounts can't*/ - if (mount(NULL, m->path, NULL, MS_REMOUNT|DEV_MOUNT_OPTIONS|MS_RDONLY, NULL) < 0) - r = -errno; - } else - return 0; - - /* Not that we only turn on the MS_RDONLY flag here, we never turn it off. Something that was marked read-only - * already stays this way. This improves compatibility with container managers, where we won't attempt to undo - * read-only mounts already applied. */ - - return r; -} - -static int chase_all_symlinks(const char *root_directory, BindMount *m, unsigned *n) { - BindMount *f, *t; - int r; - - assert(m); - assert(n); - - /* Since mount() will always follow symlinks and we need to take the different root directory into account we - * chase the symlinks on our own first. This call wil do so for all entries and remove all entries where we - * can't resolve the path, and which have been marked for such removal. */ - - for (f = m, t = m; f < m+*n; f++) { - - r = chase_symlinks(f->path, root_directory, &f->chased); - if (r == -ENOENT && f->ignore) /* Doesn't exist? Then remove it! */ - continue; - if (r < 0) - return log_debug_errno(r, "Failed to chase symlinks for %s: %m", f->path); - - if (path_equal(f->path, f->chased)) - f->chased = mfree(f->chased); - else { - log_debug("Chased %s → %s", f->path, f->chased); - f->path = f->chased; - } - - *t = *f; - t++; - } - - *n = t - m; - return 0; -} - -static unsigned namespace_calculate_mounts( - const NameSpaceInfo *ns_info, - char** read_write_paths, - char** read_only_paths, - char** inaccessible_paths, - const char* tmp_dir, - const char* var_tmp_dir, - ProtectHome protect_home, - ProtectSystem protect_system) { - - unsigned protect_home_cnt; - unsigned protect_system_cnt = - (protect_system == PROTECT_SYSTEM_STRICT ? - ELEMENTSOF(protect_system_strict_table) : - ((protect_system == PROTECT_SYSTEM_FULL) ? - ELEMENTSOF(protect_system_full_table) : - ((protect_system == PROTECT_SYSTEM_YES) ? - ELEMENTSOF(protect_system_yes_table) : 0))); - - protect_home_cnt = - (protect_home == PROTECT_HOME_YES ? - ELEMENTSOF(protect_home_yes_table) : - ((protect_home == PROTECT_HOME_READ_ONLY) ? - ELEMENTSOF(protect_home_read_only_table) : 0)); - - return !!tmp_dir + !!var_tmp_dir + - strv_length(read_write_paths) + - strv_length(read_only_paths) + - strv_length(inaccessible_paths) + - ns_info->private_dev + - (ns_info->protect_kernel_tunables ? ELEMENTSOF(protect_kernel_tunables_table) : 0) + - (ns_info->protect_control_groups ? 1 : 0) + - (ns_info->protect_kernel_modules ? ELEMENTSOF(protect_kernel_modules_table) : 0) + - protect_home_cnt + protect_system_cnt; -} - -int setup_namespace( - const char* root_directory, - const NameSpaceInfo *ns_info, - char** read_write_paths, - char** read_only_paths, - char** inaccessible_paths, - const char* tmp_dir, - const char* var_tmp_dir, - ProtectHome protect_home, - ProtectSystem protect_system, - unsigned long mount_flags) { - - BindMount *m, *mounts = NULL; - bool make_slave = false; - unsigned n; - int r = 0; - - if (mount_flags == 0) - mount_flags = MS_SHARED; - - n = namespace_calculate_mounts(ns_info, - read_write_paths, - read_only_paths, - inaccessible_paths, - tmp_dir, var_tmp_dir, - protect_home, protect_system); - - /* Set mount slave mode */ - if (root_directory || n > 0) - make_slave = true; - - if (n > 0) { - m = mounts = (BindMount *) alloca0(n * sizeof(BindMount)); - r = append_mounts(&m, read_write_paths, READWRITE); - if (r < 0) - return r; - - r = append_mounts(&m, read_only_paths, READONLY); - if (r < 0) - return r; - - r = append_mounts(&m, inaccessible_paths, INACCESSIBLE); - if (r < 0) - return r; - - if (tmp_dir) { - m->path = prefix_roota(root_directory, "/tmp"); - m->mode = PRIVATE_TMP; - m++; - } - - if (var_tmp_dir) { - m->path = prefix_roota(root_directory, "/var/tmp"); - m->mode = PRIVATE_VAR_TMP; - m++; - } - - if (ns_info->private_dev) { - m->path = prefix_roota(root_directory, "/dev"); - m->mode = PRIVATE_DEV; - m++; - } - - if (ns_info->protect_kernel_tunables) { - r = append_protect_kernel_tunables(&m, root_directory); - if (r < 0) - return r; - } - - if (ns_info->protect_kernel_modules) { - r = append_protect_kernel_modules(&m, root_directory); - if (r < 0) - return r; - } - - if (ns_info->protect_control_groups) { - m->path = prefix_roota(root_directory, "/sys/fs/cgroup"); - m->mode = READONLY; - m++; - } - - r = append_protect_home(&m, root_directory, protect_home); - if (r < 0) - return r; - - r = append_protect_system(&m, root_directory, protect_system); - if (r < 0) - return r; - - assert(mounts + n == m); - - /* Resolve symlinks manually first, as mount() will always follow them relative to the host's - * root. Moreover we want to suppress duplicates based on the resolved paths. This of course is a bit - * racy. */ - r = chase_all_symlinks(root_directory, mounts, &n); - if (r < 0) - goto finish; - - qsort(mounts, n, sizeof(BindMount), mount_path_compare); - - drop_duplicates(mounts, &n); - drop_outside_root(root_directory, mounts, &n); - drop_inaccessible(mounts, &n); - drop_nop(mounts, &n); - } - - if (unshare(CLONE_NEWNS) < 0) { - r = -errno; - goto finish; - } - - if (make_slave) { - /* Remount / as SLAVE so that nothing now mounted in the namespace - shows up in the parent */ - if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) < 0) { - r = -errno; - goto finish; - } - } - - if (root_directory) { - /* Turn directory into bind mount, if it isn't one yet */ - r = path_is_mount_point(root_directory, AT_SYMLINK_FOLLOW); - if (r < 0) - goto finish; - if (r == 0) { - if (mount(root_directory, root_directory, NULL, MS_BIND|MS_REC, NULL) < 0) { - r = -errno; - goto finish; - } - } - } - - if (n > 0) { - char **blacklist; - unsigned j; - - /* First round, add in all special mounts we need */ - for (m = mounts; m < mounts + n; ++m) { - r = apply_mount(m, tmp_dir, var_tmp_dir); - if (r < 0) - goto finish; - } - - /* Create a blacklist we can pass to bind_mount_recursive() */ - blacklist = newa(char*, n+1); - for (j = 0; j < n; j++) - blacklist[j] = (char*) mounts[j].path; - blacklist[j] = NULL; - - /* Second round, flip the ro bits if necessary. */ - for (m = mounts; m < mounts + n; ++m) { - r = make_read_only(m, blacklist); - if (r < 0) - goto finish; - } - } - - if (root_directory) { - /* MS_MOVE does not work on MS_SHARED so the remount MS_SHARED will be done later */ - r = mount_move_root(root_directory); - if (r < 0) - goto finish; - } - - /* Remount / as the desired mode. Not that this will not - * reestablish propagation from our side to the host, since - * what's disconnected is disconnected. */ - if (mount(NULL, "/", NULL, mount_flags | MS_REC, NULL) < 0) { - r = -errno; - goto finish; - } - - r = 0; - -finish: - for (m = mounts; m < mounts + n; m++) - free(m->chased); - - return r; -} - -static int setup_one_tmp_dir(const char *id, const char *prefix, char **path) { - _cleanup_free_ char *x = NULL; - char bid[SD_ID128_STRING_MAX]; - sd_id128_t boot_id; - int r; - - assert(id); - assert(prefix); - assert(path); - - /* We include the boot id in the directory so that after a - * reboot we can easily identify obsolete directories. */ - - r = sd_id128_get_boot(&boot_id); - if (r < 0) - return r; - - x = strjoin(prefix, "/systemd-private-", sd_id128_to_string(boot_id, bid), "-", id, "-XXXXXX", NULL); - if (!x) - return -ENOMEM; - - RUN_WITH_UMASK(0077) - if (!mkdtemp(x)) - return -errno; - - RUN_WITH_UMASK(0000) { - char *y; - - y = strjoina(x, "/tmp"); - - if (mkdir(y, 0777 | S_ISVTX) < 0) - return -errno; - } - - *path = x; - x = NULL; - - return 0; -} - -int setup_tmp_dirs(const char *id, char **tmp_dir, char **var_tmp_dir) { - char *a, *b; - int r; - - assert(id); - assert(tmp_dir); - assert(var_tmp_dir); - - r = setup_one_tmp_dir(id, "/tmp", &a); - if (r < 0) - return r; - - r = setup_one_tmp_dir(id, "/var/tmp", &b); - if (r < 0) { - char *t; - - t = strjoina(a, "/tmp"); - rmdir(t); - rmdir(a); - - free(a); - return r; - } - - *tmp_dir = a; - *var_tmp_dir = b; - - return 0; -} - -int setup_netns(int netns_storage_socket[2]) { - _cleanup_close_ int netns = -1; - int r, q; - - assert(netns_storage_socket); - assert(netns_storage_socket[0] >= 0); - assert(netns_storage_socket[1] >= 0); - - /* We use the passed socketpair as a storage buffer for our - * namespace reference fd. Whatever process runs this first - * shall create a new namespace, all others should just join - * it. To serialize that we use a file lock on the socket - * pair. - * - * It's a bit crazy, but hey, works great! */ - - if (lockf(netns_storage_socket[0], F_LOCK, 0) < 0) - return -errno; - - netns = receive_one_fd(netns_storage_socket[0], MSG_DONTWAIT); - if (netns == -EAGAIN) { - /* Nothing stored yet, so let's create a new namespace */ - - if (unshare(CLONE_NEWNET) < 0) { - r = -errno; - goto fail; - } - - loopback_setup(); - - netns = open("/proc/self/ns/net", O_RDONLY|O_CLOEXEC|O_NOCTTY); - if (netns < 0) { - r = -errno; - goto fail; - } - - r = 1; - - } else if (netns < 0) { - r = netns; - goto fail; - - } else { - /* Yay, found something, so let's join the namespace */ - if (setns(netns, CLONE_NEWNET) < 0) { - r = -errno; - goto fail; - } - - r = 0; - } - - q = send_one_fd(netns_storage_socket[1], netns, MSG_DONTWAIT); - if (q < 0) { - r = q; - goto fail; - } - -fail: - (void) lockf(netns_storage_socket[0], F_ULOCK, 0); - return r; -} - -static const char *const protect_home_table[_PROTECT_HOME_MAX] = { - [PROTECT_HOME_NO] = "no", - [PROTECT_HOME_YES] = "yes", - [PROTECT_HOME_READ_ONLY] = "read-only", -}; - -DEFINE_STRING_TABLE_LOOKUP(protect_home, ProtectHome); - -static const char *const protect_system_table[_PROTECT_SYSTEM_MAX] = { - [PROTECT_SYSTEM_NO] = "no", - [PROTECT_SYSTEM_YES] = "yes", - [PROTECT_SYSTEM_FULL] = "full", - [PROTECT_SYSTEM_STRICT] = "strict", -}; - -DEFINE_STRING_TABLE_LOOKUP(protect_system, ProtectSystem); |