./move.sh

1 files changed, 650 insertions, 0 deletions

diff --git a/src/libcore/namespace.c b/src/libcore/namespace.c
new file mode 100644
index 0000000000..203d122810
--- /dev/null
+++ b/src/libcore/namespace.c
@@ -0,0 +1,650 @@
+/***
+  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 "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;
+        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 == 0) {
+                /* 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", 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);
+
+        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);
+
+        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);
+                if (r == 0 && m->mode == PRIVATE_DEV) /* can be readonly but the submounts can't*/
+                        r = mount(NULL, m->path, NULL, MS_REMOUNT|DEV_MOUNT_OPTIONS|MS_RDONLY, NULL);
+        } else
+                r = 0;
+
+        if (m->ignore && r == -ENOENT)
+                return 0;
+
+        return r;
+}
+
+int setup_namespace(
+                const char* root_directory,
+                char** read_write_dirs,
+                char** read_only_dirs,
+                char** inaccessible_dirs,
+                const char* tmp_dir,
+                const char* var_tmp_dir,
+                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 +
+                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 = 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 (private_dev) {
+                        m->path = prefix_roota(root_directory, "/dev");
+                        m->mode = PRIVATE_DEV;
+                        m++;
+                }
+
+                if (protect_home != PROTECT_HOME_NO) {
+                        const char *home_dir, *run_user_dir, *root_dir;
+
+                        home_dir = prefix_roota(root_directory, "/home");
+                        home_dir = strjoina("-", home_dir);
+                        run_user_dir = prefix_roota(root_directory, "/run/user");
+                        run_user_dir = strjoina("-", run_user_dir);
+                        root_dir = prefix_roota(root_directory, "/root");
+                        root_dir = strjoina("-", root_dir);
+
+                        r = append_mounts(&m, STRV_MAKE(home_dir, run_user_dir, root_dir),
+                                protect_home == PROTECT_HOME_READ_ONLY ? READONLY : INACCESSIBLE);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (protect_system != PROTECT_SYSTEM_NO) {
+                        const char *usr_dir, *boot_dir, *etc_dir;
+
+                        usr_dir = prefix_roota(root_directory, "/usr");
+                        boot_dir = prefix_roota(root_directory, "/boot");
+                        boot_dir = strjoina("-", boot_dir);
+                        etc_dir = prefix_roota(root_directory, "/etc");
+
+                        r = append_mounts(&m, protect_system == PROTECT_SYSTEM_FULL
+                                ? STRV_MAKE(usr_dir, boot_dir, etc_dir)
+                                : STRV_MAKE(usr_dir, boot_dir), 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 || root_directory) {
+                /* 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;
+        }
+
+        if (root_directory) {
+                /* Turn directory into bind mount */
+                if (mount(root_directory, root_directory, NULL, MS_BIND|MS_REC, NULL) < 0)
+                        return -errno;
+        }
+
+        if (n > 0) {
+                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;
+                }
+        }
+
+        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);
+
+                /* at this point, we cannot rollback */
+                if (r < 0)
+                        return r;
+        }
+
+        /* 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)
+                /* at this point, we cannot rollback */
+                return -errno;
+
+        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;
+        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:
+        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);