+++ /dev/null
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-/***
- 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 <sys/mount.h>
-#include <string.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <sys/stat.h>
-#include <sched.h>
-#include <linux/fs.h>
-
-#include "strv.h"
-#include "util.h"
-#include "path-util.h"
-#include "missing.h"
-#include "loopback-setup.h"
-#include "dev-setup.h"
-#include "selinux-util.h"
-#include "namespace.h"
-
-typedef enum MountMode {
- /* This is ordered by priority! */
- INACCESSIBLE,
- READONLY,
- PRIVATE_TMP,
- PRIVATE_VAR_TMP,
- PRIVATE_DEV,
- PRIVATE_BUS_ENDPOINT,
- READWRITE
-} MountMode;
-
-typedef struct BindMount {
- const char *path;
- MountMode mode;
- bool done;
- bool ignore;
-} BindMount;
-
-static int append_mounts(BindMount **p, char **strv, MountMode mode) {
- char **i;
-
- assert(p);
-
- STRV_FOREACH(i, strv) {
-
- (*p)->ignore = false;
- (*p)->done = false;
-
- if ((mode == INACCESSIBLE || mode == READONLY || mode == READWRITE) && (*i)[0] == '-') {
- (*p)->ignore = true;
- (*i)++;
- }
-
- if (!path_is_absolute(*i))
- return -EINVAL;
-
- (*p)->path = *i;
- (*p)->mode = mode;
- (*p)++;
- }
-
- return 0;
-}
-
-static int mount_path_compare(const void *a, const void *b) {
- const BindMount *p = a, *q = b;
- int d;
-
- d = path_compare(p->path, q->path);
-
- if (!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;
- }
-
- /* If the paths are not equal, then order prefixes first */
- return d;
-}
-
-static void drop_duplicates(BindMount *m, unsigned *n) {
- BindMount *f, *t, *previous;
-
- assert(m);
- assert(n);
-
- for (f = m, t = m, previous = NULL; f < m+*n; f++) {
-
- /* The first one wins */
- if (previous && path_equal(f->path, previous->path))
- continue;
-
- *t = *f;
-
- previous = t;
-
- 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", MS_NOSUID|MS_STRICTATIME, "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);
-
- if (mount(dev, "/dev/", 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 mount_kdbus(BindMount *m) {
-
- char temporary_mount[] = "/tmp/kdbus-dev-XXXXXX";
- _cleanup_free_ char *basepath = NULL;
- _cleanup_umask_ mode_t u;
- char *busnode = NULL, *root;
- struct stat st;
- int r;
-
- assert(m);
-
- u = umask(0000);
-
- if (!mkdtemp(temporary_mount))
- return log_error_errno(errno, "Failed create temp dir: %m");
-
- root = strjoina(temporary_mount, "/kdbus");
- (void) mkdir(root, 0755);
- if (mount("tmpfs", root, "tmpfs", MS_NOSUID|MS_STRICTATIME, "mode=777") < 0) {
- r = -errno;
- goto fail;
- }
-
- /* create a new /dev/null dev node copy so we have some fodder to
- * bind-mount the custom endpoint over. */
- if (stat("/dev/null", &st) < 0) {
- log_error_errno(errno, "Failed to stat /dev/null: %m");
- r = -errno;
- goto fail;
- }
-
- busnode = strjoina(root, "/bus");
- if (mknod(busnode, (st.st_mode & ~07777) | 0600, st.st_rdev) < 0) {
- log_error_errno(errno, "mknod() for %s failed: %m", busnode);
- r = -errno;
- goto fail;
- }
-
- r = mount(m->path, busnode, NULL, MS_BIND, NULL);
- if (r < 0) {
- log_error_errno(errno, "bind mount of %s failed: %m", m->path);
- r = -errno;
- goto fail;
- }
-
- basepath = dirname_malloc(m->path);
- if (!basepath) {
- r = -ENOMEM;
- goto fail;
- }
-
- if (mount(root, basepath, NULL, MS_MOVE, NULL) < 0) {
- log_error_errno(errno, "bind mount of %s failed: %m", basepath);
- r = -errno;
- goto fail;
- }
-
- rmdir(temporary_mount);
- return 0;
-
-fail:
- if (busnode) {
- umount(busnode);
- unlink(busnode);
- }
-
- umount(root);
- rmdir(root);
- 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);
-
- switch (m->mode) {
-
- case INACCESSIBLE:
-
- /* First, get rid of everything that is below if there
- * is anything... Then, overmount it with an
- * inaccessible directory. */
- umount_recursive(m->path, 0);
-
- what = "/run/systemd/inaccessible";
- break;
-
- case READONLY:
- case READWRITE:
- /* Nothing to mount here, we just later toggle the
- * MS_RDONLY bit for the mount point */
- return 0;
-
- case PRIVATE_TMP:
- what = tmp_dir;
- break;
-
- case PRIVATE_VAR_TMP:
- what = var_tmp_dir;
- break;
-
- case PRIVATE_DEV:
- return mount_dev(m);
-
- case PRIVATE_BUS_ENDPOINT:
- return mount_kdbus(m);
-
- default:
- assert_not_reached("Unknown mode");
- }
-
- assert(what);
-
- r = mount(what, m->path, NULL, MS_BIND|MS_REC, NULL);
- if (r >= 0)
- log_debug("Successfully mounted %s to %s", what, m->path);
- else if (m->ignore && errno == ENOENT)
- return 0;
-
- return r;
-}
-
-static int make_read_only(BindMount *m) {
- int r;
-
- assert(m);
-
- if (IN_SET(m->mode, INACCESSIBLE, READONLY))
- r = bind_remount_recursive(m->path, true);
- else if (IN_SET(m->mode, READWRITE, PRIVATE_TMP, PRIVATE_VAR_TMP, PRIVATE_DEV))
- r = bind_remount_recursive(m->path, false);
- else
- r = 0;
-
- if (m->ignore && r == -ENOENT)
- return 0;
-
- return r;
-}
-
-int setup_namespace(
- char** read_write_dirs,
- char** read_only_dirs,
- char** inaccessible_dirs,
- const char* tmp_dir,
- const char* var_tmp_dir,
- const char* bus_endpoint_path,
- bool private_dev,
- ProtectHome protect_home,
- ProtectSystem protect_system,
- unsigned long mount_flags) {
-
- BindMount *m, *mounts = NULL;
- unsigned n;
- int r = 0;
-
- if (mount_flags == 0)
- mount_flags = MS_SHARED;
-
- if (unshare(CLONE_NEWNS) < 0)
- return -errno;
-
- n = !!tmp_dir + !!var_tmp_dir + !!bus_endpoint_path +
- strv_length(read_write_dirs) +
- strv_length(read_only_dirs) +
- strv_length(inaccessible_dirs) +
- private_dev +
- (protect_home != PROTECT_HOME_NO ? 3 : 0) +
- (protect_system != PROTECT_SYSTEM_NO ? 2 : 0) +
- (protect_system == PROTECT_SYSTEM_FULL ? 1 : 0);
-
- if (n > 0) {
- m = mounts = (BindMount *) alloca0(n * sizeof(BindMount));
- r = append_mounts(&m, read_write_dirs, READWRITE);
- if (r < 0)
- return r;
-
- r = append_mounts(&m, read_only_dirs, READONLY);
- if (r < 0)
- return r;
-
- r = append_mounts(&m, inaccessible_dirs, INACCESSIBLE);
- if (r < 0)
- return r;
-
- if (tmp_dir) {
- m->path = "/tmp";
- m->mode = PRIVATE_TMP;
- m++;
- }
-
- if (var_tmp_dir) {
- m->path = "/var/tmp";
- m->mode = PRIVATE_VAR_TMP;
- m++;
- }
-
- if (private_dev) {
- m->path = "/dev";
- m->mode = PRIVATE_DEV;
- m++;
- }
-
- if (bus_endpoint_path) {
- m->path = bus_endpoint_path;
- m->mode = PRIVATE_BUS_ENDPOINT;
- m++;
- }
-
- if (protect_home != PROTECT_HOME_NO) {
- r = append_mounts(&m, STRV_MAKE("-/home", "-/run/user", "-/root"), protect_home == PROTECT_HOME_READ_ONLY ? READONLY : INACCESSIBLE);
- if (r < 0)
- return r;
- }
-
- if (protect_system != PROTECT_SYSTEM_NO) {
- r = append_mounts(&m, protect_system == PROTECT_SYSTEM_FULL ? STRV_MAKE("/usr", "-/boot", "/etc") : STRV_MAKE("/usr", "-/boot"), READONLY);
- if (r < 0)
- return r;
- }
-
- assert(mounts + n == m);
-
- qsort(mounts, n, sizeof(BindMount), mount_path_compare);
- drop_duplicates(mounts, &n);
- }
-
- if (n > 0) {
- /* 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)
- return -errno;
-
- for (m = mounts; m < mounts + n; ++m) {
- r = apply_mount(m, tmp_dir, var_tmp_dir);
- if (r < 0)
- goto fail;
- }
-
- for (m = mounts; m < mounts + n; ++m) {
- r = make_read_only(m);
- if (r < 0)
- goto fail;
- }
- }
-
- /* 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 fail;
- }
-
- return 0;
-
-fail:
- if (n > 0) {
- for (m = mounts; m < mounts + n; ++m)
- if (m->done)
- (void) umount2(m->path, MNT_DETACH);
- }
-
- 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;
- union {
- struct cmsghdr cmsghdr;
- uint8_t buf[CMSG_SPACE(sizeof(int))];
- } control = {};
- struct msghdr mh = {
- .msg_control = &control,
- .msg_controllen = sizeof(control),
- };
- struct cmsghdr *cmsg;
- int r;
-
- 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;
-
- if (recvmsg(netns_storage_socket[0], &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC) < 0) {
- if (errno != EAGAIN) {
- r = -errno;
- goto fail;
- }
-
- /* 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 {
- /* Yay, found something, so let's join the namespace */
-
- for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
- if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
- assert(cmsg->cmsg_len == CMSG_LEN(sizeof(int)));
- netns = *(int*) CMSG_DATA(cmsg);
- }
- }
-
- if (setns(netns, CLONE_NEWNET) < 0) {
- r = -errno;
- goto fail;
- }
-
- r = 0;
- }
-
- cmsg = CMSG_FIRSTHDR(&mh);
- cmsg->cmsg_level = SOL_SOCKET;
- cmsg->cmsg_type = SCM_RIGHTS;
- cmsg->cmsg_len = CMSG_LEN(sizeof(int));
- memcpy(CMSG_DATA(cmsg), &netns, sizeof(int));
- mh.msg_controllen = cmsg->cmsg_len;
-
- if (sendmsg(netns_storage_socket[1], &mh, MSG_DONTWAIT|MSG_NOSIGNAL) < 0) {
- r = -errno;
- goto fail;
- }
-
-fail:
- 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",
-};
-
-DEFINE_STRING_TABLE_LOOKUP(protect_system, ProtectSystem);
~ianmdlvl / elogind.git / blobdiff