1072 lines
35 KiB
C
1072 lines
35 KiB
C
/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <sched.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/mount.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <linux/fs.h>
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#include "alloc-util.h"
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#include "dev-setup.h"
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#include "fd-util.h"
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#include "fs-util.h"
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#include "loopback-setup.h"
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#include "missing.h"
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#include "mkdir.h"
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#include "mount-util.h"
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#include "namespace.h"
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#include "path-util.h"
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#include "selinux-util.h"
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#include "socket-util.h"
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#include "string-table.h"
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#include "string-util.h"
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#include "strv.h"
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#include "umask-util.h"
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#include "user-util.h"
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#include "util.h"
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#define DEV_MOUNT_OPTIONS (MS_NOSUID|MS_STRICTATIME|MS_NOEXEC)
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typedef enum MountMode {
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/* This is ordered by priority! */
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INACCESSIBLE,
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READONLY,
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PRIVATE_TMP,
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PRIVATE_VAR_TMP,
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PRIVATE_DEV,
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READWRITE,
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} MountMode;
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typedef struct BindMount {
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const char *path_const; /* Memory allocated on stack or static */
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MountMode mode:6;
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bool ignore:1; /* Ignore if path does not exist? */
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bool has_prefix:1; /* Already is prefixed by the root dir? */
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char *path_malloc; /* Use this instead of 'path' if we had to allocate memory */
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} BindMount;
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/*
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* The following Protect tables are to protect paths and mark some of them
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* READONLY, in case a path is covered by an option from another table, then
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* it is marked READWRITE in the current one, and the more restrictive mode is
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* applied from that other table. This way all options can be combined in a
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* safe and comprehensible way for users.
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*/
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/* ProtectKernelTunables= option and the related filesystem APIs */
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static const BindMount protect_kernel_tunables_table[] = {
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{ "/proc/sys", READONLY, false },
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{ "/proc/sysrq-trigger", READONLY, true },
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{ "/proc/latency_stats", READONLY, true },
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{ "/proc/mtrr", READONLY, true },
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{ "/proc/apm", READONLY, true }, /* Obsolete API, there's no point in permitting access to this, ever */
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{ "/proc/acpi", READONLY, true },
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{ "/proc/timer_stats", READONLY, true },
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{ "/proc/asound", READONLY, true },
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{ "/proc/bus", READONLY, true },
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{ "/proc/fs", READONLY, true },
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{ "/proc/irq", READONLY, true },
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{ "/sys", READONLY, false },
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{ "/sys/kernel/debug", READONLY, true },
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{ "/sys/kernel/tracing", READONLY, true },
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{ "/sys/fs/cgroup", READWRITE, false }, /* READONLY is set by ProtectControlGroups= option */
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};
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/* ProtectKernelModules= option */
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static const BindMount protect_kernel_modules_table[] = {
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#ifdef HAVE_SPLIT_USR
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{ "/lib/modules", INACCESSIBLE, true },
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#endif
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{ "/usr/lib/modules", INACCESSIBLE, true },
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};
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/*
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* ProtectHome=read-only table, protect $HOME and $XDG_RUNTIME_DIR and rest of
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* system should be protected by ProtectSystem=
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*/
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static const BindMount protect_home_read_only_table[] = {
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{ "/home", READONLY, true },
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{ "/run/user", READONLY, true },
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{ "/root", READONLY, true },
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};
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/* ProtectHome=yes table */
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static const BindMount protect_home_yes_table[] = {
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{ "/home", INACCESSIBLE, true },
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{ "/run/user", INACCESSIBLE, true },
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{ "/root", INACCESSIBLE, true },
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};
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/* ProtectSystem=yes table */
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static const BindMount protect_system_yes_table[] = {
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{ "/usr", READONLY, false },
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{ "/boot", READONLY, true },
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{ "/efi", READONLY, true },
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};
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/* ProtectSystem=full includes ProtectSystem=yes */
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static const BindMount protect_system_full_table[] = {
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{ "/usr", READONLY, false },
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{ "/boot", READONLY, true },
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{ "/efi", READONLY, true },
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{ "/etc", READONLY, false },
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};
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/*
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* ProtectSystem=strict table. In this strict mode, we mount everything
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* read-only, except for /proc, /dev, /sys which are the kernel API VFS,
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* which are left writable, but PrivateDevices= + ProtectKernelTunables=
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* protect those, and these options should be fully orthogonal.
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* (And of course /home and friends are also left writable, as ProtectHome=
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* shall manage those, orthogonally).
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*/
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static const BindMount protect_system_strict_table[] = {
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{ "/", READONLY, false },
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{ "/proc", READWRITE, false }, /* ProtectKernelTunables= */
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{ "/sys", READWRITE, false }, /* ProtectKernelTunables= */
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{ "/dev", READWRITE, false }, /* PrivateDevices= */
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{ "/home", READWRITE, true }, /* ProtectHome= */
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{ "/run/user", READWRITE, true }, /* ProtectHome= */
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{ "/root", READWRITE, true }, /* ProtectHome= */
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};
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static const char *bind_mount_path(const BindMount *p) {
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assert(p);
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/* Returns the path of this bind mount. If the malloc()-allocated ->path_buffer field is set we return that,
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* otherwise the stack/static ->path field is returned. */
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return p->path_malloc ?: p->path_const;
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}
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static int append_access_mounts(BindMount **p, char **strv, MountMode mode) {
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char **i;
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assert(p);
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/* Adds a list of user-supplied READWRITE/READONLY/INACCESSIBLE entries */
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STRV_FOREACH(i, strv) {
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bool ignore = false, needs_prefix = false;
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const char *e = *i;
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/* Look for any prefixes */
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if (startswith(e, "-")) {
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e++;
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ignore = true;
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}
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if (startswith(e, "+")) {
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e++;
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needs_prefix = true;
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}
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if (!path_is_absolute(e))
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return -EINVAL;
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*((*p)++) = (BindMount) {
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.path_const = e,
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.mode = mode,
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.ignore = ignore,
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.has_prefix = !needs_prefix,
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};
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}
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return 0;
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}
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static int append_static_mounts(BindMount **p, const BindMount *mounts, unsigned n, bool ignore_protect) {
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unsigned i;
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assert(p);
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assert(mounts);
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/* Adds a list of static pre-defined entries */
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for (i = 0; i < n; i++)
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*((*p)++) = (BindMount) {
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.path_const = bind_mount_path(mounts+i),
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.mode = mounts[i].mode,
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.ignore = mounts[i].ignore || ignore_protect,
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};
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return 0;
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}
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static int append_protect_home(BindMount **p, ProtectHome protect_home, bool ignore_protect) {
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assert(p);
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switch (protect_home) {
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case PROTECT_HOME_NO:
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return 0;
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case PROTECT_HOME_READ_ONLY:
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return append_static_mounts(p, protect_home_read_only_table, ELEMENTSOF(protect_home_read_only_table), ignore_protect);
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case PROTECT_HOME_YES:
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return append_static_mounts(p, protect_home_yes_table, ELEMENTSOF(protect_home_yes_table), ignore_protect);
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default:
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assert_not_reached("Unexpected ProtectHome= value");
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}
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}
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static int append_protect_system(BindMount **p, ProtectSystem protect_system, bool ignore_protect) {
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assert(p);
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switch (protect_system) {
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case PROTECT_SYSTEM_NO:
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return 0;
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case PROTECT_SYSTEM_STRICT:
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return append_static_mounts(p, protect_system_strict_table, ELEMENTSOF(protect_system_strict_table), ignore_protect);
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case PROTECT_SYSTEM_YES:
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return append_static_mounts(p, protect_system_yes_table, ELEMENTSOF(protect_system_yes_table), ignore_protect);
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case PROTECT_SYSTEM_FULL:
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return append_static_mounts(p, protect_system_full_table, ELEMENTSOF(protect_system_full_table), ignore_protect);
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default:
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assert_not_reached("Unexpected ProtectSystem= value");
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}
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}
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static int mount_path_compare(const void *a, const void *b) {
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const BindMount *p = a, *q = b;
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int d;
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/* If the paths are not equal, then order prefixes first */
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d = path_compare(bind_mount_path(p), bind_mount_path(q));
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if (d != 0)
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return d;
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/* If the paths are equal, check the mode */
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if (p->mode < q->mode)
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return -1;
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if (p->mode > q->mode)
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return 1;
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return 0;
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}
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static int prefix_where_needed(BindMount *m, unsigned n, const char *root_directory) {
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unsigned i;
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/* Prefixes all paths in the bind mount table with the root directory if it is specified and the entry needs
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* that. */
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if (!root_directory)
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return 0;
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for (i = 0; i < n; i++) {
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char *s;
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if (m[i].has_prefix)
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continue;
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s = prefix_root(root_directory, bind_mount_path(m+i));
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if (!s)
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return -ENOMEM;
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free(m[i].path_malloc);
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m[i].path_malloc = s;
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m[i].has_prefix = true;
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}
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return 0;
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}
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static void drop_duplicates(BindMount *m, unsigned *n) {
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BindMount *f, *t, *previous;
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assert(m);
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assert(n);
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/* Drops duplicate entries. Expects that the array is properly ordered already. */
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for (f = m, t = m, previous = NULL; f < m + *n; f++) {
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/* The first one wins (which is the one with the more restrictive mode), see mount_path_compare()
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* above. */
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if (previous && path_equal(bind_mount_path(f), bind_mount_path(previous))) {
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log_debug("%s is duplicate.", bind_mount_path(f));
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f->path_malloc = mfree(f->path_malloc);
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continue;
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}
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*t = *f;
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previous = t;
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t++;
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}
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*n = t - m;
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}
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static void drop_inaccessible(BindMount *m, unsigned *n) {
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BindMount *f, *t;
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const char *clear = NULL;
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assert(m);
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assert(n);
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/* Drops all entries obstructed by another entry further up the tree. Expects that the array is properly
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* ordered already. */
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for (f = m, t = m; f < m + *n; f++) {
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/* If we found a path set for INACCESSIBLE earlier, and this entry has it as prefix we should drop
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* it, as inaccessible paths really should drop the entire subtree. */
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if (clear && path_startswith(bind_mount_path(f), clear)) {
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log_debug("%s is masked by %s.", bind_mount_path(f), clear);
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f->path_malloc = mfree(f->path_malloc);
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continue;
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}
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clear = f->mode == INACCESSIBLE ? bind_mount_path(f) : NULL;
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*t = *f;
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t++;
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}
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*n = t - m;
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}
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static void drop_nop(BindMount *m, unsigned *n) {
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BindMount *f, *t;
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assert(m);
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assert(n);
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/* Drops all entries which have an immediate parent that has the same type, as they are redundant. Assumes the
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* list is ordered by prefixes. */
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for (f = m, t = m; f < m + *n; f++) {
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/* Only suppress such subtrees for READONLY and READWRITE entries */
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if (IN_SET(f->mode, READONLY, READWRITE)) {
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BindMount *p;
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bool found = false;
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/* Now let's find the first parent of the entry we are looking at. */
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for (p = t-1; p >= m; p--) {
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if (path_startswith(bind_mount_path(f), bind_mount_path(p))) {
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found = true;
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break;
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}
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}
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/* We found it, let's see if it's the same mode, if so, we can drop this entry */
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if (found && p->mode == f->mode) {
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log_debug("%s is redundant by %s", bind_mount_path(f), bind_mount_path(p));
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f->path_malloc = mfree(f->path_malloc);
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continue;
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}
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}
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*t = *f;
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t++;
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}
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*n = t - m;
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}
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static void drop_outside_root(const char *root_directory, BindMount *m, unsigned *n) {
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BindMount *f, *t;
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assert(m);
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assert(n);
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/* Nothing to do */
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if (!root_directory)
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return;
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/* Drops all mounts that are outside of the root directory. */
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for (f = m, t = m; f < m + *n; f++) {
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if (!path_startswith(bind_mount_path(f), root_directory)) {
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log_debug("%s is outside of root directory.", bind_mount_path(f));
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f->path_malloc = mfree(f->path_malloc);
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continue;
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}
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*t = *f;
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t++;
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}
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*n = t - m;
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}
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static int mount_dev(BindMount *m) {
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static const char devnodes[] =
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"/dev/null\0"
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"/dev/zero\0"
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"/dev/full\0"
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"/dev/random\0"
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"/dev/urandom\0"
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"/dev/tty\0";
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char temporary_mount[] = "/tmp/namespace-dev-XXXXXX";
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const char *d, *dev = NULL, *devpts = NULL, *devshm = NULL, *devhugepages = NULL, *devmqueue = NULL, *devlog = NULL, *devptmx = NULL;
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_cleanup_umask_ mode_t u;
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int r;
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assert(m);
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u = umask(0000);
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if (!mkdtemp(temporary_mount))
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return -errno;
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dev = strjoina(temporary_mount, "/dev");
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(void) mkdir(dev, 0755);
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if (mount("tmpfs", dev, "tmpfs", DEV_MOUNT_OPTIONS, "mode=755") < 0) {
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r = -errno;
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goto fail;
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}
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devpts = strjoina(temporary_mount, "/dev/pts");
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(void) mkdir(devpts, 0755);
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if (mount("/dev/pts", devpts, NULL, MS_BIND, NULL) < 0) {
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r = -errno;
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goto fail;
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}
|
|
|
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devptmx = strjoina(temporary_mount, "/dev/ptmx");
|
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if (symlink("pts/ptmx", devptmx) < 0) {
|
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r = -errno;
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goto fail;
|
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}
|
|
|
|
devshm = strjoina(temporary_mount, "/dev/shm");
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|
(void) mkdir(devshm, 01777);
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r = mount("/dev/shm", devshm, NULL, MS_BIND, NULL);
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if (r < 0) {
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r = -errno;
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goto fail;
|
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}
|
|
|
|
devmqueue = strjoina(temporary_mount, "/dev/mqueue");
|
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(void) mkdir(devmqueue, 0755);
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(void) mount("/dev/mqueue", devmqueue, NULL, MS_BIND, NULL);
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|
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devhugepages = strjoina(temporary_mount, "/dev/hugepages");
|
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(void) mkdir(devhugepages, 0755);
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(void) mount("/dev/hugepages", devhugepages, NULL, MS_BIND, NULL);
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|
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devlog = strjoina(temporary_mount, "/dev/log");
|
|
(void) symlink("/run/systemd/journal/dev-log", devlog);
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|
|
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NULSTR_FOREACH(d, devnodes) {
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|
_cleanup_free_ char *dn = NULL;
|
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struct stat st;
|
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|
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r = stat(d, &st);
|
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if (r < 0) {
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|
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if (errno == ENOENT)
|
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continue;
|
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|
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r = -errno;
|
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goto fail;
|
|
}
|
|
|
|
if (!S_ISBLK(st.st_mode) &&
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!S_ISCHR(st.st_mode)) {
|
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r = -EINVAL;
|
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goto fail;
|
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}
|
|
|
|
if (st.st_rdev == 0)
|
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continue;
|
|
|
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dn = strappend(temporary_mount, d);
|
|
if (!dn) {
|
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r = -ENOMEM;
|
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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();
|
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|
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if (r < 0) {
|
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r = -errno;
|
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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(bind_mount_path(m), 0755);
|
|
|
|
/* Unmount everything in old /dev */
|
|
umount_recursive(bind_mount_path(m), 0);
|
|
if (mount(dev, bind_mount_path(m), 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", bind_mount_path(m));
|
|
|
|
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(bind_mount_path(m), 0);
|
|
|
|
if (lstat(bind_mount_path(m), &target) < 0)
|
|
return log_debug_errno(errno, "Failed to lstat() %s to determine what to mount over it: %m", bind_mount_path(m));
|
|
|
|
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(bind_mount_path(m), NULL, 0);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to determine whether %s is already a mount point: %m", bind_mount_path(m));
|
|
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 = bind_mount_path(m);
|
|
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, bind_mount_path(m), NULL, MS_BIND|MS_REC, NULL) < 0)
|
|
return log_debug_errno(errno, "Failed to mount %s to %s: %m", what, bind_mount_path(m));
|
|
|
|
log_debug("Successfully mounted %s to %s", what, bind_mount_path(m));
|
|
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(bind_mount_path(m), true, blacklist);
|
|
else if (m->mode == PRIVATE_DEV) { /* Can be readonly but the submounts can't*/
|
|
if (mount(NULL, bind_mount_path(m), 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;
|
|
}
|
|
|
|
/* Chase symlinks and remove failed paths from mounts */
|
|
static int chase_all_symlinks(const char *root_directory, BindMount *m, unsigned *n) {
|
|
BindMount *f, *t;
|
|
int r = 0;
|
|
|
|
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++) {
|
|
_cleanup_free_ char *chased = NULL;
|
|
int k;
|
|
|
|
k = chase_symlinks(bind_mount_path(f), root_directory, 0, &chased);
|
|
if (k < 0) {
|
|
/* Get only real errors */
|
|
if (r >= 0 && (k != -ENOENT || !f->ignore))
|
|
r = k;
|
|
|
|
/* Doesn't exist or failed? Then remove it and continue! */
|
|
log_debug_errno(k, "Failed to chase symlinks for %s: %m", bind_mount_path(f));
|
|
f->path_malloc = mfree(f->path_malloc);
|
|
continue;
|
|
}
|
|
|
|
if (!path_equal(bind_mount_path(f), chased)) {
|
|
log_debug("Chased %s → %s", bind_mount_path(f), chased);
|
|
|
|
free(f->path_malloc);
|
|
f->path_malloc = chased;
|
|
chased = NULL;
|
|
}
|
|
|
|
*t = *f;
|
|
t++;
|
|
}
|
|
|
|
*n = t - m;
|
|
return r;
|
|
}
|
|
|
|
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_mounts;
|
|
int r = 0;
|
|
|
|
if (mount_flags == 0)
|
|
mount_flags = MS_SHARED;
|
|
|
|
n_mounts = 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_mounts > 0)
|
|
make_slave = true;
|
|
|
|
if (n_mounts > 0) {
|
|
m = mounts = (BindMount *) alloca0(n_mounts * sizeof(BindMount));
|
|
r = append_access_mounts(&m, read_write_paths, READWRITE);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
r = append_access_mounts(&m, read_only_paths, READONLY);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
r = append_access_mounts(&m, inaccessible_paths, INACCESSIBLE);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
if (tmp_dir) {
|
|
*(m++) = (BindMount) {
|
|
.path_const = "/tmp",
|
|
.mode = PRIVATE_TMP,
|
|
};
|
|
}
|
|
|
|
if (var_tmp_dir) {
|
|
*(m++) = (BindMount) {
|
|
.path_const = "/var/tmp",
|
|
.mode = PRIVATE_VAR_TMP,
|
|
};
|
|
}
|
|
|
|
if (ns_info->private_dev) {
|
|
*(m++) = (BindMount) {
|
|
.path_const = "/dev",
|
|
.mode = PRIVATE_DEV,
|
|
};
|
|
}
|
|
|
|
if (ns_info->protect_kernel_tunables) {
|
|
r = append_static_mounts(&m, protect_kernel_tunables_table, ELEMENTSOF(protect_kernel_tunables_table), ns_info->ignore_protect_paths);
|
|
if (r < 0)
|
|
goto finish;
|
|
}
|
|
|
|
if (ns_info->protect_kernel_modules) {
|
|
r = append_static_mounts(&m, protect_kernel_modules_table, ELEMENTSOF(protect_kernel_modules_table), ns_info->ignore_protect_paths);
|
|
if (r < 0)
|
|
goto finish;
|
|
}
|
|
|
|
if (ns_info->protect_control_groups) {
|
|
*(m++) = (BindMount) {
|
|
.path_const = "/sys/fs/cgroup",
|
|
.mode = READONLY,
|
|
};
|
|
}
|
|
|
|
r = append_protect_home(&m, protect_home, ns_info->ignore_protect_paths);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
r = append_protect_system(&m, protect_system, false);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
assert(mounts + n_mounts == m);
|
|
|
|
/* Prepend the root directory where that's necessary */
|
|
r = prefix_where_needed(mounts, n_mounts, root_directory);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
/* 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_mounts);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
qsort(mounts, n_mounts, sizeof(BindMount), mount_path_compare);
|
|
|
|
drop_duplicates(mounts, &n_mounts);
|
|
drop_outside_root(root_directory, mounts, &n_mounts);
|
|
drop_inaccessible(mounts, &n_mounts);
|
|
drop_nop(mounts, &n_mounts);
|
|
}
|
|
|
|
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, NULL, 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_mounts > 0) {
|
|
char **blacklist;
|
|
unsigned j;
|
|
|
|
/* First round, add in all special mounts we need */
|
|
for (m = mounts; m < mounts + n_mounts; ++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_mounts+1);
|
|
for (j = 0; j < n_mounts; j++)
|
|
blacklist[j] = (char*) bind_mount_path(mounts+j);
|
|
blacklist[j] = NULL;
|
|
|
|
/* Second round, flip the ro bits if necessary. */
|
|
for (m = mounts; m < mounts + n_mounts; ++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_mounts; m++)
|
|
free(m->path_malloc);
|
|
|
|
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");
|
|
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);
|