ea2b93a8ee
The code introduced in f8c1a81c51 (= systemd 227) failed for me with:
Failed to copy smack label from net_cls to /sys/fs/cgroup/net_cls: No such file or directory
There is no need for a symlink in this case because source and target
are identical. The symlink() call is allowed to fail when the target
already exists. When that happens, copying the Smack label must be
skipped.
But the code also failed when there is a symlink, like "cpu ->
cpu,cpuacct", because mac_smack_copy() got called with
src="cpu,cpuacct" which fails to find the entry because the current
directory is not inside /sys/fs/cgroup. The absolute path to the existing
entry must be used instead.
416 lines
15 KiB
C
416 lines
15 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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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 <ftw.h>
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#include <stdlib.h>
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#include <sys/mount.h>
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#include <unistd.h>
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#include "alloc-util.h"
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#include "bus-util.h"
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#include "cgroup-util.h"
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#include "dev-setup.h"
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#include "efivars.h"
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#include "label.h"
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#include "log.h"
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#include "macro.h"
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#include "missing.h"
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#include "mkdir.h"
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#include "mount-setup.h"
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#include "mount-util.h"
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#include "path-util.h"
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#include "set.h"
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#include "smack-util.h"
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#include "strv.h"
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#include "user-util.h"
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#include "util.h"
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#include "virt.h"
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typedef enum MountMode {
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MNT_NONE = 0,
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MNT_FATAL = 1 << 0,
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MNT_IN_CONTAINER = 1 << 1,
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} MountMode;
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typedef struct MountPoint {
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const char *what;
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const char *where;
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const char *type;
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const char *options;
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unsigned long flags;
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bool (*condition_fn)(void);
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MountMode mode;
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} MountPoint;
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/* The first three entries we might need before SELinux is up. The
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* fourth (securityfs) is needed by IMA to load a custom policy. The
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* other ones we can delay until SELinux and IMA are loaded. When
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* SMACK is enabled we need smackfs, too, so it's a fifth one. */
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#ifdef HAVE_SMACK
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#define N_EARLY_MOUNT 5
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#else
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#define N_EARLY_MOUNT 4
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#endif
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static const MountPoint mount_table[] = {
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{ "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
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NULL, MNT_FATAL|MNT_IN_CONTAINER },
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{ "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
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NULL, MNT_FATAL|MNT_IN_CONTAINER },
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{ "devtmpfs", "/dev", "devtmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME,
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NULL, MNT_FATAL|MNT_IN_CONTAINER },
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{ "securityfs", "/sys/kernel/security", "securityfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
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NULL, MNT_NONE },
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#ifdef HAVE_SMACK
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{ "smackfs", "/sys/fs/smackfs", "smackfs", "smackfsdef=*", MS_NOSUID|MS_NOEXEC|MS_NODEV,
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mac_smack_use, MNT_FATAL },
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{ "tmpfs", "/dev/shm", "tmpfs", "mode=1777,smackfsroot=*", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
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mac_smack_use, MNT_FATAL },
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#endif
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{ "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
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NULL, MNT_FATAL|MNT_IN_CONTAINER },
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{ "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC,
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NULL, MNT_IN_CONTAINER },
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#ifdef HAVE_SMACK
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{ "tmpfs", "/run", "tmpfs", "mode=755,smackfsroot=*", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
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mac_smack_use, MNT_FATAL },
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#endif
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{ "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
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NULL, MNT_FATAL|MNT_IN_CONTAINER },
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{ "cgroup", "/sys/fs/cgroup", "cgroup", "__DEVEL__sane_behavior", MS_NOSUID|MS_NOEXEC|MS_NODEV,
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cg_is_unified_wanted, MNT_FATAL|MNT_IN_CONTAINER },
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{ "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME,
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cg_is_legacy_wanted, MNT_FATAL|MNT_IN_CONTAINER },
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{ "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd,xattr", MS_NOSUID|MS_NOEXEC|MS_NODEV,
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cg_is_legacy_wanted, MNT_IN_CONTAINER },
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{ "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID|MS_NOEXEC|MS_NODEV,
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cg_is_legacy_wanted, MNT_FATAL|MNT_IN_CONTAINER },
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{ "pstore", "/sys/fs/pstore", "pstore", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
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NULL, MNT_NONE },
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#ifdef ENABLE_EFI
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{ "efivarfs", "/sys/firmware/efi/efivars", "efivarfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
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is_efi_boot, MNT_NONE },
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#endif
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{ "kdbusfs", "/sys/fs/kdbus", "kdbusfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
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is_kdbus_wanted, MNT_IN_CONTAINER },
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};
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/* These are API file systems that might be mounted by other software,
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* we just list them here so that we know that we should ignore them */
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static const char ignore_paths[] =
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/* SELinux file systems */
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"/sys/fs/selinux\0"
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/* Container bind mounts */
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"/proc/sys\0"
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"/dev/console\0"
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"/proc/kmsg\0";
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bool mount_point_is_api(const char *path) {
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unsigned i;
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/* Checks if this mount point is considered "API", and hence
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* should be ignored */
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for (i = 0; i < ELEMENTSOF(mount_table); i ++)
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if (path_equal(path, mount_table[i].where))
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return true;
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return path_startswith(path, "/sys/fs/cgroup/");
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}
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bool mount_point_ignore(const char *path) {
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const char *i;
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NULSTR_FOREACH(i, ignore_paths)
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if (path_equal(path, i))
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return true;
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return false;
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}
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static int mount_one(const MountPoint *p, bool relabel) {
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int r;
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assert(p);
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if (p->condition_fn && !p->condition_fn())
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return 0;
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/* Relabel first, just in case */
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if (relabel)
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label_fix(p->where, true, true);
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r = path_is_mount_point(p->where, AT_SYMLINK_FOLLOW);
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if (r < 0 && r != -ENOENT)
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return r;
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if (r > 0)
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return 0;
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/* Skip securityfs in a container */
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if (!(p->mode & MNT_IN_CONTAINER) && detect_container() > 0)
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return 0;
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/* The access mode here doesn't really matter too much, since
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* the mounted file system will take precedence anyway. */
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if (relabel)
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mkdir_p_label(p->where, 0755);
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else
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mkdir_p(p->where, 0755);
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log_debug("Mounting %s to %s of type %s with options %s.",
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p->what,
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p->where,
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p->type,
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strna(p->options));
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if (mount(p->what,
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p->where,
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p->type,
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p->flags,
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p->options) < 0) {
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log_full((p->mode & MNT_FATAL) ? LOG_ERR : LOG_DEBUG, "Failed to mount %s at %s: %m", p->type, p->where);
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return (p->mode & MNT_FATAL) ? -errno : 0;
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}
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/* Relabel again, since we now mounted something fresh here */
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if (relabel)
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label_fix(p->where, false, false);
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return 1;
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}
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int mount_setup_early(void) {
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unsigned i;
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int r = 0;
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assert_cc(N_EARLY_MOUNT <= ELEMENTSOF(mount_table));
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/* Do a minimal mount of /proc and friends to enable the most
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* basic stuff, such as SELinux */
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for (i = 0; i < N_EARLY_MOUNT; i ++) {
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int j;
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j = mount_one(mount_table + i, false);
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if (j != 0 && r >= 0)
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r = j;
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}
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return r;
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}
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int mount_cgroup_controllers(char ***join_controllers) {
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_cleanup_set_free_free_ Set *controllers = NULL;
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int r;
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if (!cg_is_legacy_wanted())
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return 0;
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/* Mount all available cgroup controllers that are built into the kernel. */
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controllers = set_new(&string_hash_ops);
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if (!controllers)
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return log_oom();
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r = cg_kernel_controllers(controllers);
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if (r < 0)
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return log_error_errno(r, "Failed to enumerate cgroup controllers: %m");
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for (;;) {
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_cleanup_free_ char *options = NULL, *controller = NULL, *where = NULL;
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MountPoint p = {
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.what = "cgroup",
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.type = "cgroup",
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.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
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.mode = MNT_IN_CONTAINER,
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};
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char ***k = NULL;
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controller = set_steal_first(controllers);
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if (!controller)
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break;
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if (join_controllers)
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for (k = join_controllers; *k; k++)
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if (strv_find(*k, controller))
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break;
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if (k && *k) {
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char **i, **j;
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for (i = *k, j = *k; *i; i++) {
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if (!streq(*i, controller)) {
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_cleanup_free_ char *t;
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t = set_remove(controllers, *i);
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if (!t) {
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free(*i);
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continue;
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}
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}
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*(j++) = *i;
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}
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*j = NULL;
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options = strv_join(*k, ",");
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if (!options)
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return log_oom();
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} else {
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options = controller;
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controller = NULL;
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}
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where = strappend("/sys/fs/cgroup/", options);
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if (!where)
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return log_oom();
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p.where = where;
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p.options = options;
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r = mount_one(&p, true);
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if (r < 0)
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return r;
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if (r > 0 && k && *k) {
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char **i;
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for (i = *k; *i; i++) {
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_cleanup_free_ char *t = NULL;
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t = strappend("/sys/fs/cgroup/", *i);
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if (!t)
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return log_oom();
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r = symlink(options, t);
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if (r >= 0) {
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#ifdef SMACK_RUN_LABEL
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_cleanup_free_ char *src;
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src = strappend("/sys/fs/cgroup/", options);
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if (!src)
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return log_oom();
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r = mac_smack_copy(t, src);
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if (r < 0 && r != -EOPNOTSUPP)
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return log_error_errno(r, "Failed to copy smack label from %s to %s: %m", src, t);
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#endif
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} else if (errno != EEXIST)
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return log_error_errno(errno, "Failed to create symlink %s: %m", t);
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}
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}
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}
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/* Now that we mounted everything, let's make the tmpfs the
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* cgroup file systems are mounted into read-only. */
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(void) mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755");
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return 0;
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}
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#if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
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static int nftw_cb(
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const char *fpath,
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const struct stat *sb,
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int tflag,
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struct FTW *ftwbuf) {
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/* No need to label /dev twice in a row... */
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if (_unlikely_(ftwbuf->level == 0))
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return FTW_CONTINUE;
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label_fix(fpath, false, false);
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/* /run/initramfs is static data and big, no need to
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* dynamically relabel its contents at boot... */
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if (_unlikely_(ftwbuf->level == 1 &&
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tflag == FTW_D &&
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streq(fpath, "/run/initramfs")))
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return FTW_SKIP_SUBTREE;
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return FTW_CONTINUE;
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};
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#endif
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int mount_setup(bool loaded_policy) {
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unsigned i;
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int r = 0;
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for (i = 0; i < ELEMENTSOF(mount_table); i ++) {
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int j;
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j = mount_one(mount_table + i, loaded_policy);
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if (j != 0 && r >= 0)
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r = j;
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}
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if (r < 0)
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return r;
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#if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
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/* Nodes in devtmpfs and /run need to be manually updated for
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* the appropriate labels, after mounting. The other virtual
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* API file systems like /sys and /proc do not need that, they
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* use the same label for all their files. */
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if (loaded_policy) {
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usec_t before_relabel, after_relabel;
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char timespan[FORMAT_TIMESPAN_MAX];
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before_relabel = now(CLOCK_MONOTONIC);
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nftw("/dev", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL);
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nftw("/run", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL);
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after_relabel = now(CLOCK_MONOTONIC);
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log_info("Relabelled /dev and /run in %s.",
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format_timespan(timespan, sizeof(timespan), after_relabel - before_relabel, 0));
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}
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#endif
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/* Create a few default symlinks, which are normally created
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* by udevd, but some scripts might need them before we start
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* udevd. */
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dev_setup(NULL, UID_INVALID, GID_INVALID);
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/* Mark the root directory as shared in regards to mount
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* propagation. The kernel defaults to "private", but we think
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* it makes more sense to have a default of "shared" so that
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* nspawn and the container tools work out of the box. If
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* specific setups need other settings they can reset the
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* propagation mode to private if needed. */
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if (detect_container() <= 0)
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if (mount(NULL, "/", NULL, MS_REC|MS_SHARED, NULL) < 0)
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log_warning_errno(errno, "Failed to set up the root directory for shared mount propagation: %m");
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/* Create a few directories we always want around, Note that
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* sd_booted() checks for /run/systemd/system, so this mkdir
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* really needs to stay for good, otherwise software that
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* copied sd-daemon.c into their sources will misdetect
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* systemd. */
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mkdir_label("/run/systemd", 0755);
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mkdir_label("/run/systemd/system", 0755);
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mkdir_label("/run/systemd/inaccessible", 0000);
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return 0;
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}
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