8bab802910
Creates a file or a directory depending on the source path, useful for creating mount points.
2383 lines
87 KiB
C
2383 lines
87 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <errno.h>
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#include <linux/loop.h>
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#include <sched.h>
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#include <stdio.h>
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#include <sys/mount.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 "base-filesystem.h"
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#include "dev-setup.h"
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#include "fd-util.h"
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#include "format-util.h"
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#include "fs-util.h"
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#include "label.h"
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#include "list.h"
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#include "loop-util.h"
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#include "loopback-setup.h"
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#include "mkdir.h"
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#include "mount-util.h"
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#include "mountpoint-util.h"
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#include "namespace-util.h"
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#include "namespace.h"
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#include "nulstr-util.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 "sort-util.h"
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#include "stat-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 "tmpfile-util.h"
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#include "umask-util.h"
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#include "user-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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MOUNT_IMAGES,
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BIND_MOUNT,
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BIND_MOUNT_RECURSIVE,
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PRIVATE_TMP,
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PRIVATE_TMP_READONLY,
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PRIVATE_DEV,
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BIND_DEV,
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EMPTY_DIR,
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SYSFS,
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PROCFS,
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READONLY,
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READWRITE,
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TMPFS,
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READWRITE_IMPLICIT, /* Should have the lowest priority. */
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_MOUNT_MODE_MAX,
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} MountMode;
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typedef struct MountEntry {
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const char *path_const; /* Memory allocated on stack or static */
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MountMode mode:5;
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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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bool read_only:1; /* Shall this mount point be read-only? */
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bool nosuid:1; /* Shall set MS_NOSUID on the mount itself */
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bool applied:1; /* Already applied */
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char *path_malloc; /* Use this instead of 'path_const' if we had to allocate memory */
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const char *source_const; /* The source path, for bind mounts or images */
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char *source_malloc;
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const char *options_const;/* Mount options for tmpfs */
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char *options_malloc;
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unsigned long flags; /* Mount flags used by EMPTY_DIR and TMPFS. Do not include MS_RDONLY here, but please use read_only. */
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unsigned n_followed;
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LIST_HEAD(MountOptions, image_options);
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} MountEntry;
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/* If MountAPIVFS= is used, let's mount /sys and /proc into the it, but only as a fallback if the user hasn't mounted
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* something there already. These mounts are hence overridden by any other explicitly configured mounts. */
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static const MountEntry apivfs_table[] = {
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{ "/proc", PROCFS, false },
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{ "/dev", BIND_DEV, false },
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{ "/sys", SYSFS, false },
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};
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/* ProtectKernelTunables= option and the related filesystem APIs */
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static const MountEntry protect_kernel_tunables_table[] = {
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{ "/proc/acpi", 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/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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{ "/proc/kallsyms", INACCESSIBLE, true },
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{ "/proc/kcore", INACCESSIBLE, true },
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{ "/proc/latency_stats", READONLY, true },
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{ "/proc/mtrr", READONLY, true },
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{ "/proc/scsi", READONLY, true },
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{ "/proc/sys", READONLY, true },
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{ "/proc/sysrq-trigger", READONLY, true },
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{ "/proc/timer_stats", READONLY, true },
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{ "/sys", READONLY, false },
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{ "/sys/fs/bpf", READONLY, true },
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{ "/sys/fs/cgroup", READWRITE_IMPLICIT, false }, /* READONLY is set by ProtectControlGroups= option */
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{ "/sys/fs/selinux", READWRITE_IMPLICIT, true },
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{ "/sys/kernel/debug", READONLY, true },
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{ "/sys/kernel/tracing", READONLY, true },
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};
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/* ProtectKernelModules= option */
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static const MountEntry protect_kernel_modules_table[] = {
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#if 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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/* ProtectKernelLogs= option */
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static const MountEntry protect_kernel_logs_table[] = {
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{ "/proc/kmsg", INACCESSIBLE, true },
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{ "/dev/kmsg", 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 MountEntry 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=tmpfs table */
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static const MountEntry protect_home_tmpfs_table[] = {
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{ "/home", TMPFS, true, .read_only = true, .options_const = "mode=0755" TMPFS_LIMITS_EMPTY_OR_ALMOST, .flags = MS_NODEV|MS_STRICTATIME },
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{ "/run/user", TMPFS, true, .read_only = true, .options_const = "mode=0755" TMPFS_LIMITS_EMPTY_OR_ALMOST, .flags = MS_NODEV|MS_STRICTATIME },
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{ "/root", TMPFS, true, .read_only = true, .options_const = "mode=0700" TMPFS_LIMITS_EMPTY_OR_ALMOST, .flags = MS_NODEV|MS_STRICTATIME },
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};
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/* ProtectHome=yes table */
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static const MountEntry 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 MountEntry 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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#if HAVE_SPLIT_USR
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{ "/lib", READONLY, true },
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{ "/lib64", READONLY, true },
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{ "/bin", READONLY, true },
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# if HAVE_SPLIT_BIN
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{ "/sbin", READONLY, true },
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# endif
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#endif
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};
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/* ProtectSystem=full includes ProtectSystem=yes */
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static const MountEntry 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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#if HAVE_SPLIT_USR
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{ "/lib", READONLY, true },
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{ "/lib64", READONLY, true },
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{ "/bin", READONLY, true },
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# if HAVE_SPLIT_BIN
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{ "/sbin", READONLY, true },
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# endif
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#endif
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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 MountEntry protect_system_strict_table[] = {
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{ "/", READONLY, false },
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{ "/proc", READWRITE_IMPLICIT, false }, /* ProtectKernelTunables= */
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{ "/sys", READWRITE_IMPLICIT, false }, /* ProtectKernelTunables= */
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{ "/dev", READWRITE_IMPLICIT, false }, /* PrivateDevices= */
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{ "/home", READWRITE_IMPLICIT, true }, /* ProtectHome= */
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{ "/run/user", READWRITE_IMPLICIT, true }, /* ProtectHome= */
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{ "/root", READWRITE_IMPLICIT, true }, /* ProtectHome= */
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};
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static const char * const mount_mode_table[_MOUNT_MODE_MAX] = {
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[INACCESSIBLE] = "inaccessible",
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[BIND_MOUNT] = "bind",
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[BIND_MOUNT_RECURSIVE] = "rbind",
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[PRIVATE_TMP] = "private-tmp",
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[PRIVATE_DEV] = "private-dev",
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[BIND_DEV] = "bind-dev",
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[EMPTY_DIR] = "empty",
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[SYSFS] = "sysfs",
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[PROCFS] = "procfs",
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[READONLY] = "read-only",
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[READWRITE] = "read-write",
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[TMPFS] = "tmpfs",
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[MOUNT_IMAGES] = "mount-images",
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[READWRITE_IMPLICIT] = "rw-implicit",
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};
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DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(mount_mode, MountMode);
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static const char *mount_entry_path(const MountEntry *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 bool mount_entry_read_only(const MountEntry *p) {
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assert(p);
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return p->read_only || IN_SET(p->mode, READONLY, INACCESSIBLE, PRIVATE_TMP_READONLY);
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}
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static const char *mount_entry_source(const MountEntry *p) {
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assert(p);
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return p->source_malloc ?: p->source_const;
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}
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static const char *mount_entry_options(const MountEntry *p) {
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assert(p);
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return p->options_malloc ?: p->options_const;
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}
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static void mount_entry_done(MountEntry *p) {
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assert(p);
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p->path_malloc = mfree(p->path_malloc);
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p->source_malloc = mfree(p->source_malloc);
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p->options_malloc = mfree(p->options_malloc);
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p->image_options = mount_options_free_all(p->image_options);
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}
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static int append_access_mounts(MountEntry **p, char **strv, MountMode mode, bool forcibly_require_prefix) {
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char **i;
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assert(p);
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/* Adds a list of user-supplied READWRITE/READWRITE_IMPLICIT/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 log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
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"Path is not absolute: %s", e);
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*((*p)++) = (MountEntry) {
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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 && !forcibly_require_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_empty_dir_mounts(MountEntry **p, char **strv) {
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char **i;
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assert(p);
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/* Adds tmpfs mounts to provide readable but empty directories. This is primarily used to implement the
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* "/private/" boundary directories for DynamicUser=1. */
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STRV_FOREACH(i, strv) {
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*((*p)++) = (MountEntry) {
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.path_const = *i,
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.mode = EMPTY_DIR,
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.ignore = false,
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.read_only = true,
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.options_const = "mode=755" TMPFS_LIMITS_EMPTY_OR_ALMOST,
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.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME,
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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_bind_mounts(MountEntry **p, const BindMount *binds, size_t n) {
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size_t i;
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assert(p);
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for (i = 0; i < n; i++) {
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const BindMount *b = binds + i;
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*((*p)++) = (MountEntry) {
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.path_const = b->destination,
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.mode = b->recursive ? BIND_MOUNT_RECURSIVE : BIND_MOUNT,
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.read_only = b->read_only,
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.nosuid = b->nosuid,
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.source_const = b->source,
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.ignore = b->ignore_enoent,
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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_mount_images(MountEntry **p, const MountImage *mount_images, size_t n) {
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assert(p);
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for (size_t i = 0; i < n; i++) {
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const MountImage *m = mount_images + i;
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*((*p)++) = (MountEntry) {
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.path_const = m->destination,
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.mode = MOUNT_IMAGES,
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.source_const = m->source,
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.image_options = m->mount_options,
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.ignore = m->ignore_enoent,
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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_tmpfs_mounts(MountEntry **p, const TemporaryFileSystem *tmpfs, size_t n) {
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assert(p);
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for (size_t i = 0; i < n; i++) {
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const TemporaryFileSystem *t = tmpfs + i;
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_cleanup_free_ char *o = NULL, *str = NULL;
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unsigned long flags;
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bool ro = false;
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int r;
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if (!path_is_absolute(t->path))
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return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
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"Path is not absolute: %s",
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t->path);
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str = strjoin("mode=0755" NESTED_TMPFS_LIMITS ",", t->options);
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if (!str)
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return -ENOMEM;
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r = mount_option_mangle(str, MS_NODEV|MS_STRICTATIME, &flags, &o);
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if (r < 0)
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return log_debug_errno(r, "Failed to parse mount option '%s': %m", str);
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ro = flags & MS_RDONLY;
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if (ro)
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flags ^= MS_RDONLY;
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*((*p)++) = (MountEntry) {
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.path_const = t->path,
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.mode = TMPFS,
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.read_only = ro,
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.options_malloc = TAKE_PTR(o),
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.flags = flags,
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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(MountEntry **p, const MountEntry *mounts, size_t n, bool ignore_protect) {
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size_t 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)++) = (MountEntry) {
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.path_const = mount_entry_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(MountEntry **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_TMPFS:
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return append_static_mounts(p, protect_home_tmpfs_table, ELEMENTSOF(protect_home_tmpfs_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(MountEntry **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 MountEntry *a, const MountEntry *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(mount_entry_path(a), mount_entry_path(b));
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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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return CMP((int) a->mode, (int) b->mode);
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}
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static int prefix_where_needed(MountEntry *m, size_t n, const char *root_directory) {
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size_t i;
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/* Prefixes all paths in the bind mount table with the root directory if the entry needs that. */
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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 = path_join(root_directory, mount_entry_path(m+i));
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if (!s)
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return -ENOMEM;
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free_and_replace(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(MountEntry *m, size_t *n) {
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MountEntry *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++) {
|
|
|
|
/* The first one wins (which is the one with the more restrictive mode), see mount_path_compare()
|
|
* above. Note that we only drop duplicates that haven't been mounted yet. */
|
|
if (previous &&
|
|
path_equal(mount_entry_path(f), mount_entry_path(previous)) &&
|
|
!f->applied && !previous->applied) {
|
|
log_debug("%s (%s) is duplicate.", mount_entry_path(f), mount_mode_to_string(f->mode));
|
|
previous->read_only = previous->read_only || mount_entry_read_only(f); /* Propagate the read-only flag to the remaining entry */
|
|
mount_entry_done(f);
|
|
continue;
|
|
}
|
|
|
|
*t = *f;
|
|
previous = t;
|
|
t++;
|
|
}
|
|
|
|
*n = t - m;
|
|
}
|
|
|
|
static void drop_inaccessible(MountEntry *m, size_t *n) {
|
|
MountEntry *f, *t;
|
|
const char *clear = NULL;
|
|
|
|
assert(m);
|
|
assert(n);
|
|
|
|
/* Drops all entries obstructed by another entry further up the tree. Expects that the array is properly
|
|
* ordered already. */
|
|
|
|
for (f = m, t = m; f < m + *n; f++) {
|
|
|
|
/* If we found a path set for INACCESSIBLE earlier, and this entry has it as prefix we should drop
|
|
* it, as inaccessible paths really should drop the entire subtree. */
|
|
if (clear && path_startswith(mount_entry_path(f), clear)) {
|
|
log_debug("%s is masked by %s.", mount_entry_path(f), clear);
|
|
mount_entry_done(f);
|
|
continue;
|
|
}
|
|
|
|
clear = f->mode == INACCESSIBLE ? mount_entry_path(f) : NULL;
|
|
|
|
*t = *f;
|
|
t++;
|
|
}
|
|
|
|
*n = t - m;
|
|
}
|
|
|
|
static void drop_nop(MountEntry *m, size_t *n) {
|
|
MountEntry *f, *t;
|
|
|
|
assert(m);
|
|
assert(n);
|
|
|
|
/* Drops all entries which have an immediate parent that has the same type, as they are redundant. Assumes the
|
|
* list is ordered by prefixes. */
|
|
|
|
for (f = m, t = m; f < m + *n; f++) {
|
|
|
|
/* Only suppress such subtrees for READONLY, READWRITE and READWRITE_IMPLICIT entries */
|
|
if (IN_SET(f->mode, READONLY, READWRITE, READWRITE_IMPLICIT)) {
|
|
MountEntry *p;
|
|
bool found = false;
|
|
|
|
/* Now let's find the first parent of the entry we are looking at. */
|
|
for (p = t-1; p >= m; p--) {
|
|
if (path_startswith(mount_entry_path(f), mount_entry_path(p))) {
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* We found it, let's see if it's the same mode, if so, we can drop this entry */
|
|
if (found && p->mode == f->mode) {
|
|
log_debug("%s (%s) is made redundant by %s (%s)",
|
|
mount_entry_path(f), mount_mode_to_string(f->mode),
|
|
mount_entry_path(p), mount_mode_to_string(p->mode));
|
|
mount_entry_done(f);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
*t = *f;
|
|
t++;
|
|
}
|
|
|
|
*n = t - m;
|
|
}
|
|
|
|
static void drop_outside_root(const char *root_directory, MountEntry *m, size_t *n) {
|
|
MountEntry *f, *t;
|
|
|
|
assert(m);
|
|
assert(n);
|
|
|
|
/* Nothing to do */
|
|
if (!root_directory)
|
|
return;
|
|
|
|
/* Drops all mounts that are outside of the root directory. */
|
|
|
|
for (f = m, t = m; f < m + *n; f++) {
|
|
|
|
if (!path_startswith(mount_entry_path(f), root_directory)) {
|
|
log_debug("%s is outside of root directory.", mount_entry_path(f));
|
|
mount_entry_done(f);
|
|
continue;
|
|
}
|
|
|
|
*t = *f;
|
|
t++;
|
|
}
|
|
|
|
*n = t - m;
|
|
}
|
|
|
|
static int clone_device_node(
|
|
const char *d,
|
|
const char *temporary_mount,
|
|
bool *make_devnode) {
|
|
|
|
_cleanup_free_ char *sl = NULL;
|
|
const char *dn, *bn, *t;
|
|
struct stat st;
|
|
int r;
|
|
|
|
if (stat(d, &st) < 0) {
|
|
if (errno == ENOENT) {
|
|
log_debug_errno(errno, "Device node '%s' to clone does not exist, ignoring.", d);
|
|
return -ENXIO;
|
|
}
|
|
|
|
return log_debug_errno(errno, "Failed to stat() device node '%s' to clone, ignoring: %m", d);
|
|
}
|
|
|
|
if (!S_ISBLK(st.st_mode) &&
|
|
!S_ISCHR(st.st_mode))
|
|
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
|
|
"Device node '%s' to clone is not a device node, ignoring.",
|
|
d);
|
|
|
|
dn = strjoina(temporary_mount, d);
|
|
|
|
/* First, try to create device node properly */
|
|
if (*make_devnode) {
|
|
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)
|
|
goto add_symlink;
|
|
if (errno != EPERM)
|
|
return log_debug_errno(errno, "mknod failed for %s: %m", d);
|
|
|
|
/* This didn't work, let's not try this again for the next iterations. */
|
|
*make_devnode = false;
|
|
}
|
|
|
|
/* We're about to fall back to bind-mounting the device
|
|
* node. So create a dummy bind-mount target.
|
|
* Do not prepare device-node SELinux label (see issue 13762) */
|
|
r = mknod(dn, S_IFREG, 0);
|
|
if (r < 0 && errno != EEXIST)
|
|
return log_debug_errno(errno, "mknod() fallback failed for '%s': %m", d);
|
|
|
|
/* Fallback to bind-mounting: The assumption here is that all used device nodes carry standard
|
|
* properties. Specifically, the devices nodes we bind-mount should either be owned by root:root or
|
|
* root:tty (e.g. /dev/tty, /dev/ptmx) and should not carry ACLs. */
|
|
r = mount_nofollow_verbose(LOG_DEBUG, d, dn, NULL, MS_BIND, NULL);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
add_symlink:
|
|
bn = path_startswith(d, "/dev/");
|
|
if (!bn)
|
|
return 0;
|
|
|
|
/* Create symlinks like /dev/char/1:9 → ../urandom */
|
|
if (asprintf(&sl, "%s/dev/%s/%u:%u",
|
|
temporary_mount,
|
|
S_ISCHR(st.st_mode) ? "char" : "block",
|
|
major(st.st_rdev), minor(st.st_rdev)) < 0)
|
|
return log_oom();
|
|
|
|
(void) mkdir_parents(sl, 0755);
|
|
|
|
t = strjoina("../", bn);
|
|
if (symlink(t, sl) < 0)
|
|
log_debug_errno(errno, "Failed to symlink '%s' to '%s', ignoring: %m", t, sl);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int mount_private_dev(MountEntry *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;
|
|
bool can_mknod = true;
|
|
_cleanup_umask_ mode_t u;
|
|
int r;
|
|
|
|
assert(m);
|
|
|
|
u = umask(0000);
|
|
|
|
if (!mkdtemp(temporary_mount))
|
|
return log_debug_errno(errno, "Failed to create temporary directory '%s': %m", temporary_mount);
|
|
|
|
dev = strjoina(temporary_mount, "/dev");
|
|
(void) mkdir(dev, 0755);
|
|
r = mount_nofollow_verbose(LOG_DEBUG, "tmpfs", dev, "tmpfs", DEV_MOUNT_OPTIONS, "mode=755" TMPFS_LIMITS_DEV);
|
|
if (r < 0)
|
|
goto fail;
|
|
|
|
r = label_fix_container(dev, "/dev", 0);
|
|
if (r < 0) {
|
|
log_debug_errno(errno, "Failed to fix label of '%s' as /dev: %m", dev);
|
|
goto fail;
|
|
}
|
|
|
|
devpts = strjoina(temporary_mount, "/dev/pts");
|
|
(void) mkdir(devpts, 0755);
|
|
r = mount_nofollow_verbose(LOG_DEBUG, "/dev/pts", devpts, NULL, MS_BIND, NULL);
|
|
if (r < 0)
|
|
goto fail;
|
|
|
|
/* /dev/ptmx can either be a device node or a symlink to /dev/pts/ptmx.
|
|
* When /dev/ptmx a device node, /dev/pts/ptmx has 000 permissions making it inaccessible.
|
|
* Thus, in that case make a clone.
|
|
* In nspawn and other containers it will be a symlink, in that case make it a symlink. */
|
|
r = is_symlink("/dev/ptmx");
|
|
if (r < 0) {
|
|
log_debug_errno(r, "Failed to detect whether /dev/ptmx is a symlink or not: %m");
|
|
goto fail;
|
|
} else if (r > 0) {
|
|
devptmx = strjoina(temporary_mount, "/dev/ptmx");
|
|
if (symlink("pts/ptmx", devptmx) < 0) {
|
|
r = log_debug_errno(errno, "Failed to create a symlink '%s' to pts/ptmx: %m", devptmx);
|
|
goto fail;
|
|
}
|
|
} else {
|
|
r = clone_device_node("/dev/ptmx", temporary_mount, &can_mknod);
|
|
if (r < 0)
|
|
goto fail;
|
|
}
|
|
|
|
devshm = strjoina(temporary_mount, "/dev/shm");
|
|
(void) mkdir(devshm, 0755);
|
|
r = mount_nofollow_verbose(LOG_DEBUG, "/dev/shm", devshm, NULL, MS_BIND, NULL);
|
|
if (r < 0)
|
|
goto fail;
|
|
|
|
devmqueue = strjoina(temporary_mount, "/dev/mqueue");
|
|
(void) mkdir(devmqueue, 0755);
|
|
(void) mount_nofollow_verbose(LOG_DEBUG, "/dev/mqueue", devmqueue, NULL, MS_BIND, NULL);
|
|
|
|
devhugepages = strjoina(temporary_mount, "/dev/hugepages");
|
|
(void) mkdir(devhugepages, 0755);
|
|
(void) mount_nofollow_verbose(LOG_DEBUG, "/dev/hugepages", devhugepages, NULL, MS_BIND, NULL);
|
|
|
|
devlog = strjoina(temporary_mount, "/dev/log");
|
|
if (symlink("/run/systemd/journal/dev-log", devlog) < 0)
|
|
log_debug_errno(errno, "Failed to create a symlink '%s' to /run/systemd/journal/dev-log, ignoring: %m", devlog);
|
|
|
|
NULSTR_FOREACH(d, devnodes) {
|
|
r = clone_device_node(d, temporary_mount, &can_mknod);
|
|
/* ENXIO means the *source* is not a device file, skip creation in that case */
|
|
if (r < 0 && r != -ENXIO)
|
|
goto fail;
|
|
}
|
|
|
|
r = dev_setup(temporary_mount, UID_INVALID, GID_INVALID);
|
|
if (r < 0)
|
|
log_debug_errno(r, "Failed to set up basic device tree at '%s', ignoring: %m", temporary_mount);
|
|
|
|
/* 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(mount_entry_path(m), 0755);
|
|
|
|
/* Unmount everything in old /dev */
|
|
r = umount_recursive(mount_entry_path(m), 0);
|
|
if (r < 0)
|
|
log_debug_errno(r, "Failed to unmount directories below '%s', ignoring: %m", mount_entry_path(m));
|
|
|
|
r = mount_nofollow_verbose(LOG_DEBUG, dev, mount_entry_path(m), NULL, MS_MOVE, NULL);
|
|
if (r < 0)
|
|
goto fail;
|
|
|
|
(void) rmdir(dev);
|
|
(void) rmdir(temporary_mount);
|
|
|
|
return 0;
|
|
|
|
fail:
|
|
if (devpts)
|
|
(void) umount_verbose(LOG_DEBUG, devpts, UMOUNT_NOFOLLOW);
|
|
|
|
if (devshm)
|
|
(void) umount_verbose(LOG_DEBUG, devshm, UMOUNT_NOFOLLOW);
|
|
|
|
if (devhugepages)
|
|
(void) umount_verbose(LOG_DEBUG, devhugepages, UMOUNT_NOFOLLOW);
|
|
|
|
if (devmqueue)
|
|
(void) umount_verbose(LOG_DEBUG, devmqueue, UMOUNT_NOFOLLOW);
|
|
|
|
(void) umount_verbose(LOG_DEBUG, dev, UMOUNT_NOFOLLOW);
|
|
(void) rmdir(dev);
|
|
(void) rmdir(temporary_mount);
|
|
|
|
return r;
|
|
}
|
|
|
|
static int mount_bind_dev(const MountEntry *m) {
|
|
int r;
|
|
|
|
assert(m);
|
|
|
|
/* Implements the little brother of mount_private_dev(): simply bind mounts the host's /dev into the service's
|
|
* /dev. This is only used when RootDirectory= is set. */
|
|
|
|
(void) mkdir_p_label(mount_entry_path(m), 0755);
|
|
|
|
r = path_is_mount_point(mount_entry_path(m), NULL, 0);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Unable to determine whether /dev is already mounted: %m");
|
|
if (r > 0) /* make this a NOP if /dev is already a mount point */
|
|
return 0;
|
|
|
|
r = mount_nofollow_verbose(LOG_DEBUG, "/dev", mount_entry_path(m), NULL, MS_BIND|MS_REC, NULL);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int mount_sysfs(const MountEntry *m) {
|
|
int r;
|
|
|
|
assert(m);
|
|
|
|
(void) mkdir_p_label(mount_entry_path(m), 0755);
|
|
|
|
r = path_is_mount_point(mount_entry_path(m), NULL, 0);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Unable to determine whether /sys is already mounted: %m");
|
|
if (r > 0) /* make this a NOP if /sys is already a mount point */
|
|
return 0;
|
|
|
|
/* Bind mount the host's version so that we get all child mounts of it, too. */
|
|
r = mount_nofollow_verbose(LOG_DEBUG, "/sys", mount_entry_path(m), NULL, MS_BIND|MS_REC, NULL);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int mount_procfs(const MountEntry *m, const NamespaceInfo *ns_info) {
|
|
_cleanup_free_ char *opts = NULL;
|
|
const char *entry_path;
|
|
int r, n;
|
|
|
|
assert(m);
|
|
assert(ns_info);
|
|
|
|
if (ns_info->protect_proc != PROTECT_PROC_DEFAULT ||
|
|
ns_info->proc_subset != PROC_SUBSET_ALL) {
|
|
|
|
/* Starting with kernel 5.8 procfs' hidepid= logic is truly per-instance (previously it
|
|
* pretended to be per-instance but actually was per-namespace), hence let's make use of it
|
|
* if requested. To make sure this logic succeeds only on kernels where hidepid= is
|
|
* per-instance, we'll exclusively use the textual value for hidepid=, since support was
|
|
* added in the same commit: if it's supported it is thus also per-instance. */
|
|
|
|
opts = strjoin("hidepid=",
|
|
ns_info->protect_proc == PROTECT_PROC_DEFAULT ? "off" :
|
|
protect_proc_to_string(ns_info->protect_proc),
|
|
ns_info->proc_subset == PROC_SUBSET_PID ? ",subset=pid" : "");
|
|
if (!opts)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
entry_path = mount_entry_path(m);
|
|
(void) mkdir_p_label(entry_path, 0755);
|
|
|
|
/* Mount a new instance, so that we get the one that matches our user namespace, if we are running in
|
|
* one. i.e we don't reuse existing mounts here under any condition, we want a new instance owned by
|
|
* our user namespace and with our hidepid= settings applied. Hence, let's get rid of everything
|
|
* mounted on /proc/ first. */
|
|
|
|
n = umount_recursive(entry_path, 0);
|
|
|
|
r = mount_nofollow_verbose(LOG_DEBUG, "proc", entry_path, "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, opts);
|
|
if (r == -EINVAL && opts)
|
|
/* If this failed with EINVAL then this likely means the textual hidepid= stuff is
|
|
* not supported by the kernel, and thus the per-instance hidepid= neither, which
|
|
* means we really don't want to use it, since it would affect our host's /proc
|
|
* mount. Hence let's gracefully fallback to a classic, unrestricted version. */
|
|
r = mount_nofollow_verbose(LOG_DEBUG, "proc", entry_path, "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL);
|
|
if (r == -EPERM) {
|
|
/* When we do not have enough privileges to mount /proc, fallback to use existing /proc. */
|
|
|
|
if (n > 0)
|
|
/* /proc or some of sub-mounts are umounted in the above. Refuse incomplete tree.
|
|
* Propagate the original error code returned by mount() in the above. */
|
|
return -EPERM;
|
|
|
|
r = path_is_mount_point(entry_path, NULL, 0);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Unable to determine whether /proc is already mounted: %m");
|
|
if (r == 0)
|
|
/* /proc is not mounted. Propagate the original error code. */
|
|
return -EPERM;
|
|
} else if (r < 0)
|
|
return r;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int mount_tmpfs(const MountEntry *m) {
|
|
const char *entry_path, *inner_path;
|
|
int r;
|
|
|
|
assert(m);
|
|
|
|
entry_path = mount_entry_path(m);
|
|
inner_path = m->path_const;
|
|
|
|
/* First, get rid of everything that is below if there is anything. Then, overmount with our new tmpfs */
|
|
|
|
(void) mkdir_p_label(entry_path, 0755);
|
|
(void) umount_recursive(entry_path, 0);
|
|
|
|
r = mount_nofollow_verbose(LOG_DEBUG, "tmpfs", entry_path, "tmpfs", m->flags, mount_entry_options(m));
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = label_fix_container(entry_path, inner_path, 0);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to fix label of '%s' as '%s': %m", entry_path, inner_path);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int mount_images(const MountEntry *m) {
|
|
_cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
|
|
_cleanup_(decrypted_image_unrefp) DecryptedImage *decrypted_image = NULL;
|
|
_cleanup_(dissected_image_unrefp) DissectedImage *dissected_image = NULL;
|
|
_cleanup_(verity_settings_done) VeritySettings verity = VERITY_SETTINGS_DEFAULT;
|
|
DissectImageFlags dissect_image_flags;
|
|
int r;
|
|
|
|
assert(m);
|
|
|
|
r = verity_settings_load(&verity, mount_entry_source(m), NULL, NULL);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to load root hash: %m");
|
|
|
|
dissect_image_flags =
|
|
(m->read_only ? DISSECT_IMAGE_READ_ONLY : 0) |
|
|
(verity.data_path ? DISSECT_IMAGE_NO_PARTITION_TABLE : 0);
|
|
|
|
r = loop_device_make_by_path(
|
|
mount_entry_source(m),
|
|
m->read_only ? O_RDONLY : -1 /* < 0 means writable if possible, read-only as fallback */,
|
|
verity.data_path ? 0 : LO_FLAGS_PARTSCAN,
|
|
&loop_device);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to create loop device for image: %m");
|
|
|
|
r = dissect_image(
|
|
loop_device->fd,
|
|
&verity,
|
|
m->image_options,
|
|
dissect_image_flags,
|
|
&dissected_image);
|
|
/* No partition table? Might be a single-filesystem image, try again */
|
|
if (!verity.data_path && r == -ENOPKG)
|
|
r = dissect_image(
|
|
loop_device->fd,
|
|
&verity,
|
|
m->image_options,
|
|
dissect_image_flags|DISSECT_IMAGE_NO_PARTITION_TABLE,
|
|
&dissected_image);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to dissect image: %m");
|
|
|
|
r = dissected_image_decrypt(
|
|
dissected_image,
|
|
NULL,
|
|
&verity,
|
|
dissect_image_flags,
|
|
&decrypted_image);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to decrypt dissected image: %m");
|
|
|
|
r = mkdir_p_label(mount_entry_path(m), 0755);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to create destination directory %s: %m", mount_entry_path(m));
|
|
r = umount_recursive(mount_entry_path(m), 0);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to umount under destination directory %s: %m", mount_entry_path(m));
|
|
|
|
r = dissected_image_mount(dissected_image, mount_entry_path(m), UID_INVALID, dissect_image_flags);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to mount image: %m");
|
|
|
|
if (decrypted_image) {
|
|
r = decrypted_image_relinquish(decrypted_image);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to relinquish decrypted image: %m");
|
|
}
|
|
|
|
loop_device_relinquish(loop_device);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int follow_symlink(
|
|
const char *root_directory,
|
|
MountEntry *m) {
|
|
|
|
_cleanup_free_ char *target = NULL;
|
|
int r;
|
|
|
|
/* Let's chase symlinks, but only one step at a time. That's because depending where the symlink points we
|
|
* might need to change the order in which we mount stuff. Hence: let's normalize piecemeal, and do one step at
|
|
* a time by specifying CHASE_STEP. This function returns 0 if we resolved one step, and > 0 if we reached the
|
|
* end and already have a fully normalized name. */
|
|
|
|
r = chase_symlinks(mount_entry_path(m), root_directory, CHASE_STEP|CHASE_NONEXISTENT, &target, NULL);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to chase symlinks '%s': %m", mount_entry_path(m));
|
|
if (r > 0) /* Reached the end, nothing more to resolve */
|
|
return 1;
|
|
|
|
if (m->n_followed >= CHASE_SYMLINKS_MAX) /* put a boundary on things */
|
|
return log_debug_errno(SYNTHETIC_ERRNO(ELOOP),
|
|
"Symlink loop on '%s'.",
|
|
mount_entry_path(m));
|
|
|
|
log_debug("Followed mount entry path symlink %s → %s.", mount_entry_path(m), target);
|
|
|
|
free_and_replace(m->path_malloc, target);
|
|
m->has_prefix = true;
|
|
|
|
m->n_followed ++;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int apply_mount(
|
|
const char *root_directory,
|
|
MountEntry *m,
|
|
const NamespaceInfo *ns_info) {
|
|
|
|
_cleanup_free_ char *inaccessible = NULL;
|
|
bool rbind = true, make = false;
|
|
const char *what;
|
|
int r;
|
|
|
|
assert(m);
|
|
assert(ns_info);
|
|
|
|
log_debug("Applying namespace mount on %s", mount_entry_path(m));
|
|
|
|
switch (m->mode) {
|
|
|
|
case INACCESSIBLE: {
|
|
_cleanup_free_ char *tmp = NULL;
|
|
const char *runtime_dir;
|
|
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(mount_entry_path(m), 0);
|
|
|
|
if (lstat(mount_entry_path(m), &target) < 0) {
|
|
if (errno == ENOENT && m->ignore)
|
|
return 0;
|
|
|
|
return log_debug_errno(errno, "Failed to lstat() %s to determine what to mount over it: %m",
|
|
mount_entry_path(m));
|
|
}
|
|
|
|
if (geteuid() == 0)
|
|
runtime_dir = "/run";
|
|
else {
|
|
if (asprintf(&tmp, "/run/user/" UID_FMT, geteuid()) < 0)
|
|
return -ENOMEM;
|
|
|
|
runtime_dir = tmp;
|
|
}
|
|
|
|
r = mode_to_inaccessible_node(runtime_dir, target.st_mode, &inaccessible);
|
|
if (r < 0)
|
|
return log_debug_errno(SYNTHETIC_ERRNO(ELOOP),
|
|
"File type not supported for inaccessible mounts. Note that symlinks are not allowed");
|
|
what = inaccessible;
|
|
break;
|
|
}
|
|
|
|
case READONLY:
|
|
case READWRITE:
|
|
case READWRITE_IMPLICIT:
|
|
r = path_is_mount_point(mount_entry_path(m), root_directory, 0);
|
|
if (r == -ENOENT && m->ignore)
|
|
return 0;
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to determine whether %s is already a mount point: %m",
|
|
mount_entry_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 = mount_entry_path(m);
|
|
break;
|
|
|
|
case BIND_MOUNT:
|
|
rbind = false;
|
|
|
|
_fallthrough_;
|
|
case BIND_MOUNT_RECURSIVE: {
|
|
_cleanup_free_ char *chased = NULL;
|
|
|
|
/* Since mount() will always follow symlinks we chase the symlinks on our own first. Note
|
|
* that bind mount source paths are always relative to the host root, hence we pass NULL as
|
|
* root directory to chase_symlinks() here. */
|
|
|
|
r = chase_symlinks(mount_entry_source(m), NULL, CHASE_TRAIL_SLASH, &chased, NULL);
|
|
if (r == -ENOENT && m->ignore) {
|
|
log_debug_errno(r, "Path %s does not exist, ignoring.", mount_entry_source(m));
|
|
return 0;
|
|
}
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to follow symlinks on %s: %m", mount_entry_source(m));
|
|
|
|
log_debug("Followed source symlinks %s → %s.", mount_entry_source(m), chased);
|
|
|
|
free_and_replace(m->source_malloc, chased);
|
|
|
|
what = mount_entry_source(m);
|
|
make = true;
|
|
break;
|
|
}
|
|
|
|
case EMPTY_DIR:
|
|
case TMPFS:
|
|
return mount_tmpfs(m);
|
|
|
|
case PRIVATE_TMP:
|
|
case PRIVATE_TMP_READONLY:
|
|
what = mount_entry_source(m);
|
|
make = true;
|
|
break;
|
|
|
|
case PRIVATE_DEV:
|
|
return mount_private_dev(m);
|
|
|
|
case BIND_DEV:
|
|
return mount_bind_dev(m);
|
|
|
|
case SYSFS:
|
|
return mount_sysfs(m);
|
|
|
|
case PROCFS:
|
|
return mount_procfs(m, ns_info);
|
|
|
|
case MOUNT_IMAGES:
|
|
return mount_images(m);
|
|
|
|
default:
|
|
assert_not_reached("Unknown mode");
|
|
}
|
|
|
|
assert(what);
|
|
|
|
r = mount_nofollow_verbose(LOG_DEBUG, what, mount_entry_path(m), NULL, MS_BIND|(rbind ? MS_REC : 0), NULL);
|
|
if (r < 0) {
|
|
bool try_again = false;
|
|
|
|
if (r == -ENOENT && make) {
|
|
int q;
|
|
|
|
/* Hmm, either the source or the destination are missing. Let's see if we can create
|
|
the destination, then try again. */
|
|
|
|
(void) mkdir_parents(mount_entry_path(m), 0755);
|
|
|
|
q = make_mount_point_inode_from_path(what, mount_entry_path(m), 0755);
|
|
if (q < 0)
|
|
log_error_errno(q, "Failed to create destination mount point node '%s': %m",
|
|
mount_entry_path(m));
|
|
else
|
|
try_again = true;
|
|
}
|
|
|
|
if (try_again)
|
|
r = mount_nofollow_verbose(LOG_DEBUG, what, mount_entry_path(m), NULL, MS_BIND|(rbind ? MS_REC : 0), NULL);
|
|
if (r < 0)
|
|
return log_error_errno(r, "Failed to mount %s to %s: %m", what, mount_entry_path(m));
|
|
}
|
|
|
|
log_debug("Successfully mounted %s to %s", what, mount_entry_path(m));
|
|
return 0;
|
|
}
|
|
|
|
static int make_read_only(const MountEntry *m, char **deny_list, FILE *proc_self_mountinfo) {
|
|
unsigned long new_flags = 0, flags_mask = 0;
|
|
bool submounts = false;
|
|
int r = 0;
|
|
|
|
assert(m);
|
|
assert(proc_self_mountinfo);
|
|
|
|
if (mount_entry_read_only(m) || m->mode == PRIVATE_DEV) {
|
|
new_flags |= MS_RDONLY;
|
|
flags_mask |= MS_RDONLY;
|
|
}
|
|
|
|
if (m->nosuid) {
|
|
new_flags |= MS_NOSUID;
|
|
flags_mask |= MS_NOSUID;
|
|
}
|
|
|
|
if (flags_mask == 0) /* No Change? */
|
|
return 0;
|
|
|
|
/* We generally apply these changes recursively, except for /dev, and the cases we know there's
|
|
* nothing further down. Set /dev readonly, but not submounts like /dev/shm. Also, we only set the
|
|
* per-mount read-only flag. We can't set it on the superblock, if we are inside a user namespace
|
|
* and running Linux <= 4.17. */
|
|
submounts =
|
|
mount_entry_read_only(m) &&
|
|
!IN_SET(m->mode, EMPTY_DIR, TMPFS);
|
|
if (submounts)
|
|
r = bind_remount_recursive_with_mountinfo(mount_entry_path(m), new_flags, flags_mask, deny_list, proc_self_mountinfo);
|
|
else
|
|
r = bind_remount_one_with_mountinfo(mount_entry_path(m), new_flags, flags_mask, proc_self_mountinfo);
|
|
|
|
/* 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. */
|
|
|
|
if (r == -ENOENT && m->ignore)
|
|
return 0;
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to re-mount '%s'%s: %m", mount_entry_path(m),
|
|
submounts ? " and its submounts" : "");
|
|
return 0;
|
|
}
|
|
|
|
static bool namespace_info_mount_apivfs(const NamespaceInfo *ns_info) {
|
|
assert(ns_info);
|
|
|
|
/*
|
|
* ProtectControlGroups= and ProtectKernelTunables= imply MountAPIVFS=,
|
|
* since to protect the API VFS mounts, they need to be around in the
|
|
* first place...
|
|
*/
|
|
|
|
return ns_info->mount_apivfs ||
|
|
ns_info->protect_control_groups ||
|
|
ns_info->protect_kernel_tunables ||
|
|
ns_info->protect_proc != PROTECT_PROC_DEFAULT ||
|
|
ns_info->proc_subset != PROC_SUBSET_ALL;
|
|
}
|
|
|
|
static size_t namespace_calculate_mounts(
|
|
const NamespaceInfo *ns_info,
|
|
char** read_write_paths,
|
|
char** read_only_paths,
|
|
char** inaccessible_paths,
|
|
char** empty_directories,
|
|
size_t n_bind_mounts,
|
|
size_t n_temporary_filesystems,
|
|
size_t n_mount_images,
|
|
const char* tmp_dir,
|
|
const char* var_tmp_dir,
|
|
const char *creds_path,
|
|
const char* log_namespace) {
|
|
|
|
size_t protect_home_cnt;
|
|
size_t protect_system_cnt =
|
|
(ns_info->protect_system == PROTECT_SYSTEM_STRICT ?
|
|
ELEMENTSOF(protect_system_strict_table) :
|
|
((ns_info->protect_system == PROTECT_SYSTEM_FULL) ?
|
|
ELEMENTSOF(protect_system_full_table) :
|
|
((ns_info->protect_system == PROTECT_SYSTEM_YES) ?
|
|
ELEMENTSOF(protect_system_yes_table) : 0)));
|
|
|
|
protect_home_cnt =
|
|
(ns_info->protect_home == PROTECT_HOME_YES ?
|
|
ELEMENTSOF(protect_home_yes_table) :
|
|
((ns_info->protect_home == PROTECT_HOME_READ_ONLY) ?
|
|
ELEMENTSOF(protect_home_read_only_table) :
|
|
((ns_info->protect_home == PROTECT_HOME_TMPFS) ?
|
|
ELEMENTSOF(protect_home_tmpfs_table) : 0)));
|
|
|
|
return !!tmp_dir + !!var_tmp_dir +
|
|
strv_length(read_write_paths) +
|
|
strv_length(read_only_paths) +
|
|
strv_length(inaccessible_paths) +
|
|
strv_length(empty_directories) +
|
|
n_bind_mounts +
|
|
n_mount_images +
|
|
n_temporary_filesystems +
|
|
ns_info->private_dev +
|
|
(ns_info->protect_kernel_tunables ? ELEMENTSOF(protect_kernel_tunables_table) : 0) +
|
|
(ns_info->protect_kernel_modules ? ELEMENTSOF(protect_kernel_modules_table) : 0) +
|
|
(ns_info->protect_kernel_logs ? ELEMENTSOF(protect_kernel_logs_table) : 0) +
|
|
(ns_info->protect_control_groups ? 1 : 0) +
|
|
protect_home_cnt + protect_system_cnt +
|
|
(ns_info->protect_hostname ? 2 : 0) +
|
|
(namespace_info_mount_apivfs(ns_info) ? ELEMENTSOF(apivfs_table) : 0) +
|
|
(creds_path ? 2 : 1) +
|
|
!!log_namespace;
|
|
}
|
|
|
|
static void normalize_mounts(const char *root_directory, MountEntry *mounts, size_t *n_mounts) {
|
|
assert(root_directory);
|
|
assert(n_mounts);
|
|
assert(mounts || *n_mounts == 0);
|
|
|
|
typesafe_qsort(mounts, *n_mounts, 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);
|
|
}
|
|
|
|
static bool root_read_only(
|
|
char **read_only_paths,
|
|
ProtectSystem protect_system) {
|
|
|
|
/* Determine whether the root directory is going to be read-only given the configured settings. */
|
|
|
|
if (protect_system == PROTECT_SYSTEM_STRICT)
|
|
return true;
|
|
|
|
if (prefixed_path_strv_contains(read_only_paths, "/"))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
static bool home_read_only(
|
|
char** read_only_paths,
|
|
char** inaccessible_paths,
|
|
char** empty_directories,
|
|
const BindMount *bind_mounts,
|
|
size_t n_bind_mounts,
|
|
const TemporaryFileSystem *temporary_filesystems,
|
|
size_t n_temporary_filesystems,
|
|
ProtectHome protect_home) {
|
|
|
|
size_t i;
|
|
|
|
/* Determine whether the /home directory is going to be read-only given the configured settings. Yes,
|
|
* this is a bit sloppy, since we don't bother checking for cases where / is affected by multiple
|
|
* settings. */
|
|
|
|
if (protect_home != PROTECT_HOME_NO)
|
|
return true;
|
|
|
|
if (prefixed_path_strv_contains(read_only_paths, "/home") ||
|
|
prefixed_path_strv_contains(inaccessible_paths, "/home") ||
|
|
prefixed_path_strv_contains(empty_directories, "/home"))
|
|
return true;
|
|
|
|
for (i = 0; i < n_temporary_filesystems; i++)
|
|
if (path_equal(temporary_filesystems[i].path, "/home"))
|
|
return true;
|
|
|
|
/* If /home is overmounted with some dir from the host it's not writable. */
|
|
for (i = 0; i < n_bind_mounts; i++)
|
|
if (path_equal(bind_mounts[i].destination, "/home"))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
static int verity_settings_prepare(
|
|
VeritySettings *verity,
|
|
const char *root_image,
|
|
const void *root_hash,
|
|
size_t root_hash_size,
|
|
const char *root_hash_path,
|
|
const void *root_hash_sig,
|
|
size_t root_hash_sig_size,
|
|
const char *root_hash_sig_path,
|
|
const char *verity_data_path) {
|
|
|
|
int r;
|
|
|
|
assert(verity);
|
|
|
|
if (root_hash) {
|
|
void *d;
|
|
|
|
d = memdup(root_hash, root_hash_size);
|
|
if (!d)
|
|
return -ENOMEM;
|
|
|
|
free_and_replace(verity->root_hash, d);
|
|
verity->root_hash_size = root_hash_size;
|
|
verity->designator = PARTITION_ROOT;
|
|
}
|
|
|
|
if (root_hash_sig) {
|
|
void *d;
|
|
|
|
d = memdup(root_hash_sig, root_hash_sig_size);
|
|
if (!d)
|
|
return -ENOMEM;
|
|
|
|
free_and_replace(verity->root_hash_sig, d);
|
|
verity->root_hash_sig_size = root_hash_sig_size;
|
|
verity->designator = PARTITION_ROOT;
|
|
}
|
|
|
|
if (verity_data_path) {
|
|
r = free_and_strdup(&verity->data_path, verity_data_path);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
r = verity_settings_load(
|
|
verity,
|
|
root_image,
|
|
root_hash_path,
|
|
root_hash_sig_path);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to load root hash: %m");
|
|
|
|
return 0;
|
|
}
|
|
|
|
int setup_namespace(
|
|
const char* root_directory,
|
|
const char* root_image,
|
|
const MountOptions *root_image_options,
|
|
const NamespaceInfo *ns_info,
|
|
char** read_write_paths,
|
|
char** read_only_paths,
|
|
char** inaccessible_paths,
|
|
char** empty_directories,
|
|
const BindMount *bind_mounts,
|
|
size_t n_bind_mounts,
|
|
const TemporaryFileSystem *temporary_filesystems,
|
|
size_t n_temporary_filesystems,
|
|
const MountImage *mount_images,
|
|
size_t n_mount_images,
|
|
const char* tmp_dir,
|
|
const char* var_tmp_dir,
|
|
const char *creds_path,
|
|
const char *log_namespace,
|
|
unsigned long mount_flags,
|
|
const void *root_hash,
|
|
size_t root_hash_size,
|
|
const char *root_hash_path,
|
|
const void *root_hash_sig,
|
|
size_t root_hash_sig_size,
|
|
const char *root_hash_sig_path,
|
|
const char *verity_data_path,
|
|
DissectImageFlags dissect_image_flags,
|
|
char **error_path) {
|
|
|
|
_cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
|
|
_cleanup_(decrypted_image_unrefp) DecryptedImage *decrypted_image = NULL;
|
|
_cleanup_(dissected_image_unrefp) DissectedImage *dissected_image = NULL;
|
|
_cleanup_(verity_settings_done) VeritySettings verity = VERITY_SETTINGS_DEFAULT;
|
|
MountEntry *m = NULL, *mounts = NULL;
|
|
bool require_prefix = false;
|
|
const char *root;
|
|
size_t n_mounts;
|
|
int r;
|
|
|
|
assert(ns_info);
|
|
|
|
if (mount_flags == 0)
|
|
mount_flags = MS_SHARED;
|
|
|
|
if (root_image) {
|
|
dissect_image_flags |= DISSECT_IMAGE_REQUIRE_ROOT;
|
|
|
|
/* Make the whole image read-only if we can determine that we only access it in a read-only fashion. */
|
|
if (root_read_only(read_only_paths,
|
|
ns_info->protect_system) &&
|
|
home_read_only(read_only_paths, inaccessible_paths, empty_directories,
|
|
bind_mounts, n_bind_mounts, temporary_filesystems, n_temporary_filesystems,
|
|
ns_info->protect_home) &&
|
|
strv_isempty(read_write_paths))
|
|
dissect_image_flags |= DISSECT_IMAGE_READ_ONLY;
|
|
|
|
r = verity_settings_prepare(
|
|
&verity,
|
|
root_image,
|
|
root_hash, root_hash_size, root_hash_path,
|
|
root_hash_sig, root_hash_sig_size, root_hash_sig_path,
|
|
verity_data_path);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
SET_FLAG(dissect_image_flags, DISSECT_IMAGE_NO_PARTITION_TABLE, verity.data_path);
|
|
|
|
r = loop_device_make_by_path(
|
|
root_image,
|
|
FLAGS_SET(dissect_image_flags, DISSECT_IMAGE_READ_ONLY) ? O_RDONLY : -1 /* < 0 means writable if possible, read-only as fallback */,
|
|
FLAGS_SET(dissect_image_flags, DISSECT_IMAGE_NO_PARTITION_TABLE) ? 0 : LO_FLAGS_PARTSCAN,
|
|
&loop_device);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to create loop device for root image: %m");
|
|
|
|
r = dissect_image(
|
|
loop_device->fd,
|
|
&verity,
|
|
root_image_options,
|
|
dissect_image_flags,
|
|
&dissected_image);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to dissect image: %m");
|
|
|
|
r = dissected_image_decrypt(
|
|
dissected_image,
|
|
NULL,
|
|
&verity,
|
|
dissect_image_flags,
|
|
&decrypted_image);
|
|
if (r < 0)
|
|
return log_debug_errno(r, "Failed to decrypt dissected image: %m");
|
|
}
|
|
|
|
if (root_directory)
|
|
root = root_directory;
|
|
else {
|
|
/* /run/systemd should have been created by PID 1 early on already, but in some cases, like
|
|
* when running tests (test-execute), it might not have been created yet so let's make sure
|
|
* we create it if it doesn't already exist. */
|
|
(void) mkdir_p_label("/run/systemd", 0755);
|
|
|
|
/* Always create the mount namespace in a temporary directory, instead of operating
|
|
* directly in the root. The temporary directory prevents any mounts from being
|
|
* potentially obscured my other mounts we already applied.
|
|
* We use the same mount point for all images, which is safe, since they all live
|
|
* in their own namespaces after all, and hence won't see each other. */
|
|
|
|
root = "/run/systemd/unit-root";
|
|
(void) mkdir_label(root, 0700);
|
|
require_prefix = true;
|
|
}
|
|
|
|
n_mounts = namespace_calculate_mounts(
|
|
ns_info,
|
|
read_write_paths,
|
|
read_only_paths,
|
|
inaccessible_paths,
|
|
empty_directories,
|
|
n_bind_mounts,
|
|
n_temporary_filesystems,
|
|
n_mount_images,
|
|
tmp_dir, var_tmp_dir,
|
|
creds_path,
|
|
log_namespace);
|
|
|
|
if (n_mounts > 0) {
|
|
m = mounts = new0(MountEntry, n_mounts);
|
|
if (!mounts)
|
|
return -ENOMEM;
|
|
|
|
r = append_access_mounts(&m, read_write_paths, READWRITE, require_prefix);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
r = append_access_mounts(&m, read_only_paths, READONLY, require_prefix);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
r = append_access_mounts(&m, inaccessible_paths, INACCESSIBLE, require_prefix);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
r = append_empty_dir_mounts(&m, empty_directories);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
r = append_bind_mounts(&m, bind_mounts, n_bind_mounts);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
r = append_tmpfs_mounts(&m, temporary_filesystems, n_temporary_filesystems);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
if (tmp_dir) {
|
|
bool ro = streq(tmp_dir, RUN_SYSTEMD_EMPTY);
|
|
|
|
*(m++) = (MountEntry) {
|
|
.path_const = "/tmp",
|
|
.mode = ro ? PRIVATE_TMP_READONLY : PRIVATE_TMP,
|
|
.source_const = tmp_dir,
|
|
};
|
|
}
|
|
|
|
if (var_tmp_dir) {
|
|
bool ro = streq(var_tmp_dir, RUN_SYSTEMD_EMPTY);
|
|
|
|
*(m++) = (MountEntry) {
|
|
.path_const = "/var/tmp",
|
|
.mode = ro ? PRIVATE_TMP_READONLY : PRIVATE_TMP,
|
|
.source_const = var_tmp_dir,
|
|
};
|
|
}
|
|
|
|
r = append_mount_images(&m, mount_images, n_mount_images);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
if (ns_info->private_dev)
|
|
*(m++) = (MountEntry) {
|
|
.path_const = "/dev",
|
|
.mode = PRIVATE_DEV,
|
|
.flags = DEV_MOUNT_OPTIONS,
|
|
};
|
|
|
|
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_kernel_logs) {
|
|
r = append_static_mounts(&m,
|
|
protect_kernel_logs_table,
|
|
ELEMENTSOF(protect_kernel_logs_table),
|
|
ns_info->ignore_protect_paths);
|
|
if (r < 0)
|
|
goto finish;
|
|
}
|
|
|
|
if (ns_info->protect_control_groups)
|
|
*(m++) = (MountEntry) {
|
|
.path_const = "/sys/fs/cgroup",
|
|
.mode = READONLY,
|
|
};
|
|
|
|
r = append_protect_home(&m, ns_info->protect_home, ns_info->ignore_protect_paths);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
r = append_protect_system(&m, ns_info->protect_system, false);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
if (namespace_info_mount_apivfs(ns_info)) {
|
|
r = append_static_mounts(&m,
|
|
apivfs_table,
|
|
ELEMENTSOF(apivfs_table),
|
|
ns_info->ignore_protect_paths);
|
|
if (r < 0)
|
|
goto finish;
|
|
}
|
|
|
|
if (ns_info->protect_hostname) {
|
|
*(m++) = (MountEntry) {
|
|
.path_const = "/proc/sys/kernel/hostname",
|
|
.mode = READONLY,
|
|
};
|
|
*(m++) = (MountEntry) {
|
|
.path_const = "/proc/sys/kernel/domainname",
|
|
.mode = READONLY,
|
|
};
|
|
}
|
|
|
|
if (creds_path) {
|
|
/* If our service has a credentials store configured, then bind that one in, but hide
|
|
* everything else. */
|
|
|
|
*(m++) = (MountEntry) {
|
|
.path_const = "/run/credentials",
|
|
.mode = TMPFS,
|
|
.read_only = true,
|
|
.options_const = "mode=0755" TMPFS_LIMITS_EMPTY_OR_ALMOST,
|
|
.flags = MS_NODEV|MS_STRICTATIME|MS_NOSUID|MS_NOEXEC,
|
|
};
|
|
|
|
*(m++) = (MountEntry) {
|
|
.path_const = creds_path,
|
|
.mode = BIND_MOUNT,
|
|
.read_only = true,
|
|
.source_const = creds_path,
|
|
};
|
|
} else {
|
|
/* If our service has no credentials store configured, then make the whole
|
|
* credentials tree inaccessible wholesale. */
|
|
|
|
*(m++) = (MountEntry) {
|
|
.path_const = "/run/credentials",
|
|
.mode = INACCESSIBLE,
|
|
.ignore = true,
|
|
};
|
|
}
|
|
|
|
if (log_namespace) {
|
|
_cleanup_free_ char *q;
|
|
|
|
q = strjoin("/run/systemd/journal.", log_namespace);
|
|
if (!q) {
|
|
r = -ENOMEM;
|
|
goto finish;
|
|
}
|
|
|
|
*(m++) = (MountEntry) {
|
|
.path_const = "/run/systemd/journal",
|
|
.mode = BIND_MOUNT_RECURSIVE,
|
|
.read_only = true,
|
|
.source_malloc = TAKE_PTR(q),
|
|
};
|
|
}
|
|
|
|
assert(mounts + n_mounts == m);
|
|
|
|
/* Prepend the root directory where that's necessary */
|
|
r = prefix_where_needed(mounts, n_mounts, root);
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
normalize_mounts(root, mounts, &n_mounts);
|
|
}
|
|
|
|
/* All above is just preparation, figuring out what to do. Let's now actually start doing something. */
|
|
|
|
if (unshare(CLONE_NEWNS) < 0) {
|
|
r = log_debug_errno(errno, "Failed to unshare the mount namespace: %m");
|
|
if (IN_SET(r, -EACCES, -EPERM, -EOPNOTSUPP, -ENOSYS))
|
|
/* If the kernel doesn't support namespaces, or when there's a MAC or seccomp filter
|
|
* in place that doesn't allow us to create namespaces (or a missing cap), then
|
|
* propagate a recognizable error back, which the caller can use to detect this case
|
|
* (and only this) and optionally continue without namespacing applied. */
|
|
r = -ENOANO;
|
|
|
|
goto finish;
|
|
}
|
|
|
|
/* 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 = log_debug_errno(errno, "Failed to remount '/' as SLAVE: %m");
|
|
goto finish;
|
|
}
|
|
|
|
if (root_image) {
|
|
/* A root image is specified, mount it to the right place */
|
|
r = dissected_image_mount(dissected_image, root, UID_INVALID, dissect_image_flags);
|
|
if (r < 0) {
|
|
log_debug_errno(r, "Failed to mount root image: %m");
|
|
goto finish;
|
|
}
|
|
|
|
if (decrypted_image) {
|
|
r = decrypted_image_relinquish(decrypted_image);
|
|
if (r < 0) {
|
|
log_debug_errno(r, "Failed to relinquish decrypted image: %m");
|
|
goto finish;
|
|
}
|
|
}
|
|
|
|
loop_device_relinquish(loop_device);
|
|
|
|
} else if (root_directory) {
|
|
|
|
/* A root directory is specified. Turn its directory into bind mount, if it isn't one yet. */
|
|
r = path_is_mount_point(root, NULL, AT_SYMLINK_FOLLOW);
|
|
if (r < 0) {
|
|
log_debug_errno(r, "Failed to detect that %s is a mount point or not: %m", root);
|
|
goto finish;
|
|
}
|
|
if (r == 0) {
|
|
r = mount_nofollow_verbose(LOG_DEBUG, root, root, NULL, MS_BIND|MS_REC, NULL);
|
|
if (r < 0)
|
|
goto finish;
|
|
}
|
|
|
|
} else {
|
|
/* Let's mount the main root directory to the root directory to use */
|
|
r = mount_nofollow_verbose(LOG_DEBUG, "/", root, NULL, MS_BIND|MS_REC, NULL);
|
|
if (r < 0)
|
|
goto finish;
|
|
}
|
|
|
|
/* Try to set up the new root directory before mounting anything else there. */
|
|
if (root_image || root_directory)
|
|
(void) base_filesystem_create(root, UID_INVALID, GID_INVALID);
|
|
|
|
if (n_mounts > 0) {
|
|
_cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
|
|
_cleanup_free_ char **deny_list = NULL;
|
|
size_t j;
|
|
|
|
/* Open /proc/self/mountinfo now as it may become unavailable if we mount anything on top of
|
|
* /proc. For example, this is the case with the option: 'InaccessiblePaths=/proc'. */
|
|
proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
|
|
if (!proc_self_mountinfo) {
|
|
r = log_debug_errno(errno, "Failed to open /proc/self/mountinfo: %m");
|
|
if (error_path)
|
|
*error_path = strdup("/proc/self/mountinfo");
|
|
goto finish;
|
|
}
|
|
|
|
/* First round, establish all mounts we need */
|
|
for (;;) {
|
|
bool again = false;
|
|
|
|
for (m = mounts; m < mounts + n_mounts; ++m) {
|
|
|
|
if (m->applied)
|
|
continue;
|
|
|
|
r = follow_symlink(root, m);
|
|
if (r < 0) {
|
|
if (error_path && mount_entry_path(m))
|
|
*error_path = strdup(mount_entry_path(m));
|
|
goto finish;
|
|
}
|
|
if (r == 0) {
|
|
/* We hit a symlinked mount point. The entry got rewritten and might
|
|
* point to a very different place now. Let's normalize the changed
|
|
* list, and start from the beginning. After all to mount the entry
|
|
* at the new location we might need some other mounts first */
|
|
again = true;
|
|
break;
|
|
}
|
|
|
|
r = apply_mount(root, m, ns_info);
|
|
if (r < 0) {
|
|
if (error_path && mount_entry_path(m))
|
|
*error_path = strdup(mount_entry_path(m));
|
|
goto finish;
|
|
}
|
|
|
|
m->applied = true;
|
|
}
|
|
|
|
if (!again)
|
|
break;
|
|
|
|
normalize_mounts(root, mounts, &n_mounts);
|
|
}
|
|
|
|
/* Create a deny list we can pass to bind_mount_recursive() */
|
|
deny_list = new(char*, n_mounts+1);
|
|
if (!deny_list) {
|
|
r = -ENOMEM;
|
|
goto finish;
|
|
}
|
|
for (j = 0; j < n_mounts; j++)
|
|
deny_list[j] = (char*) mount_entry_path(mounts+j);
|
|
deny_list[j] = NULL;
|
|
|
|
/* Second round, flip the ro bits if necessary. */
|
|
for (m = mounts; m < mounts + n_mounts; ++m) {
|
|
r = make_read_only(m, deny_list, proc_self_mountinfo);
|
|
if (r < 0) {
|
|
if (error_path && mount_entry_path(m))
|
|
*error_path = strdup(mount_entry_path(m));
|
|
goto finish;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* MS_MOVE does not work on MS_SHARED so the remount MS_SHARED will be done later */
|
|
r = mount_move_root(root);
|
|
if (r < 0) {
|
|
log_debug_errno(r, "Failed to mount root with MS_MOVE: %m");
|
|
goto finish;
|
|
}
|
|
|
|
/* Remount / as the desired mode. Note 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 = log_debug_errno(errno, "Failed to remount '/' with desired mount flags: %m");
|
|
goto finish;
|
|
}
|
|
|
|
r = 0;
|
|
|
|
finish:
|
|
if (n_mounts > 0)
|
|
for (m = mounts; m < mounts + n_mounts; m++)
|
|
mount_entry_done(m);
|
|
|
|
free(mounts);
|
|
|
|
return r;
|
|
}
|
|
|
|
void bind_mount_free_many(BindMount *b, size_t n) {
|
|
size_t i;
|
|
|
|
assert(b || n == 0);
|
|
|
|
for (i = 0; i < n; i++) {
|
|
free(b[i].source);
|
|
free(b[i].destination);
|
|
}
|
|
|
|
free(b);
|
|
}
|
|
|
|
int bind_mount_add(BindMount **b, size_t *n, const BindMount *item) {
|
|
_cleanup_free_ char *s = NULL, *d = NULL;
|
|
BindMount *c;
|
|
|
|
assert(b);
|
|
assert(n);
|
|
assert(item);
|
|
|
|
s = strdup(item->source);
|
|
if (!s)
|
|
return -ENOMEM;
|
|
|
|
d = strdup(item->destination);
|
|
if (!d)
|
|
return -ENOMEM;
|
|
|
|
c = reallocarray(*b, *n + 1, sizeof(BindMount));
|
|
if (!c)
|
|
return -ENOMEM;
|
|
|
|
*b = c;
|
|
|
|
c[(*n) ++] = (BindMount) {
|
|
.source = TAKE_PTR(s),
|
|
.destination = TAKE_PTR(d),
|
|
.read_only = item->read_only,
|
|
.nosuid = item->nosuid,
|
|
.recursive = item->recursive,
|
|
.ignore_enoent = item->ignore_enoent,
|
|
};
|
|
|
|
return 0;
|
|
}
|
|
|
|
MountImage* mount_image_free_many(MountImage *m, size_t *n) {
|
|
size_t i;
|
|
|
|
assert(n);
|
|
assert(m || *n == 0);
|
|
|
|
for (i = 0; i < *n; i++) {
|
|
free(m[i].source);
|
|
free(m[i].destination);
|
|
mount_options_free_all(m[i].mount_options);
|
|
}
|
|
|
|
free(m);
|
|
*n = 0;
|
|
return NULL;
|
|
}
|
|
|
|
int mount_image_add(MountImage **m, size_t *n, const MountImage *item) {
|
|
_cleanup_free_ char *s = NULL, *d = NULL;
|
|
_cleanup_(mount_options_free_allp) MountOptions *options = NULL;
|
|
MountOptions *i;
|
|
MountImage *c;
|
|
|
|
assert(m);
|
|
assert(n);
|
|
assert(item);
|
|
|
|
s = strdup(item->source);
|
|
if (!s)
|
|
return -ENOMEM;
|
|
|
|
d = strdup(item->destination);
|
|
if (!d)
|
|
return -ENOMEM;
|
|
|
|
LIST_FOREACH(mount_options, i, item->mount_options) {
|
|
_cleanup_(mount_options_free_allp) MountOptions *o;
|
|
|
|
o = new(MountOptions, 1);
|
|
if (!o)
|
|
return -ENOMEM;
|
|
|
|
*o = (MountOptions) {
|
|
.partition_designator = i->partition_designator,
|
|
.options = strdup(i->options),
|
|
};
|
|
if (!o->options)
|
|
return -ENOMEM;
|
|
|
|
LIST_APPEND(mount_options, options, TAKE_PTR(o));
|
|
}
|
|
|
|
c = reallocarray(*m, *n + 1, sizeof(MountImage));
|
|
if (!c)
|
|
return -ENOMEM;
|
|
|
|
*m = c;
|
|
|
|
c[(*n) ++] = (MountImage) {
|
|
.source = TAKE_PTR(s),
|
|
.destination = TAKE_PTR(d),
|
|
.mount_options = TAKE_PTR(options),
|
|
.ignore_enoent = item->ignore_enoent,
|
|
};
|
|
|
|
return 0;
|
|
}
|
|
|
|
void temporary_filesystem_free_many(TemporaryFileSystem *t, size_t n) {
|
|
size_t i;
|
|
|
|
assert(t || n == 0);
|
|
|
|
for (i = 0; i < n; i++) {
|
|
free(t[i].path);
|
|
free(t[i].options);
|
|
}
|
|
|
|
free(t);
|
|
}
|
|
|
|
int temporary_filesystem_add(
|
|
TemporaryFileSystem **t,
|
|
size_t *n,
|
|
const char *path,
|
|
const char *options) {
|
|
|
|
_cleanup_free_ char *p = NULL, *o = NULL;
|
|
TemporaryFileSystem *c;
|
|
|
|
assert(t);
|
|
assert(n);
|
|
assert(path);
|
|
|
|
p = strdup(path);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
|
|
if (!isempty(options)) {
|
|
o = strdup(options);
|
|
if (!o)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
c = reallocarray(*t, *n + 1, sizeof(TemporaryFileSystem));
|
|
if (!c)
|
|
return -ENOMEM;
|
|
|
|
*t = c;
|
|
|
|
c[(*n) ++] = (TemporaryFileSystem) {
|
|
.path = TAKE_PTR(p),
|
|
.options = TAKE_PTR(o),
|
|
};
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int make_tmp_prefix(const char *prefix) {
|
|
_cleanup_free_ char *t = NULL;
|
|
int r;
|
|
|
|
/* Don't do anything unless we know the dir is actually missing */
|
|
r = access(prefix, F_OK);
|
|
if (r >= 0)
|
|
return 0;
|
|
if (errno != ENOENT)
|
|
return -errno;
|
|
|
|
r = mkdir_parents(prefix, 0755);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = tempfn_random(prefix, NULL, &t);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
if (mkdir(t, 0777) < 0)
|
|
return -errno;
|
|
|
|
if (chmod(t, 01777) < 0) {
|
|
r = -errno;
|
|
(void) rmdir(t);
|
|
return r;
|
|
}
|
|
|
|
if (rename(t, prefix) < 0) {
|
|
r = -errno;
|
|
(void) rmdir(t);
|
|
return r == -EEXIST ? 0 : r; /* it's fine if someone else created the dir by now */
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
static int setup_one_tmp_dir(const char *id, const char *prefix, char **path, char **tmp_path) {
|
|
_cleanup_free_ char *x = NULL;
|
|
_cleanup_free_ char *y = NULL;
|
|
char bid[SD_ID128_STRING_MAX];
|
|
sd_id128_t boot_id;
|
|
bool rw = true;
|
|
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;
|
|
|
|
r = make_tmp_prefix(prefix);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
RUN_WITH_UMASK(0077)
|
|
if (!mkdtemp(x)) {
|
|
if (errno == EROFS || ERRNO_IS_DISK_SPACE(errno))
|
|
rw = false;
|
|
else
|
|
return -errno;
|
|
}
|
|
|
|
if (rw) {
|
|
y = strjoin(x, "/tmp");
|
|
if (!y)
|
|
return -ENOMEM;
|
|
|
|
RUN_WITH_UMASK(0000) {
|
|
if (mkdir(y, 0777 | S_ISVTX) < 0)
|
|
return -errno;
|
|
}
|
|
|
|
r = label_fix_container(y, prefix, 0);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
if (tmp_path)
|
|
*tmp_path = TAKE_PTR(y);
|
|
} else {
|
|
/* Trouble: we failed to create the directory. Instead of failing, let's simulate /tmp being
|
|
* read-only. This way the service will get the EROFS result as if it was writing to the real
|
|
* file system. */
|
|
r = mkdir_p(RUN_SYSTEMD_EMPTY, 0500);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = free_and_strdup(&x, RUN_SYSTEMD_EMPTY);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
*path = TAKE_PTR(x);
|
|
return 0;
|
|
}
|
|
|
|
int setup_tmp_dirs(const char *id, char **tmp_dir, char **var_tmp_dir) {
|
|
_cleanup_(namespace_cleanup_tmpdirp) char *a = NULL;
|
|
_cleanup_(rmdir_and_freep) char *a_tmp = NULL;
|
|
char *b;
|
|
int r;
|
|
|
|
assert(id);
|
|
assert(tmp_dir);
|
|
assert(var_tmp_dir);
|
|
|
|
r = setup_one_tmp_dir(id, "/tmp", &a, &a_tmp);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = setup_one_tmp_dir(id, "/var/tmp", &b, NULL);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
a_tmp = mfree(a_tmp); /* avoid rmdir */
|
|
*tmp_dir = TAKE_PTR(a);
|
|
*var_tmp_dir = TAKE_PTR(b);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int setup_netns(const int netns_storage_socket[static 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;
|
|
}
|
|
|
|
(void) 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;
|
|
}
|
|
|
|
int open_netns_path(const int netns_storage_socket[static 2], const char *path) {
|
|
_cleanup_close_ int netns = -1;
|
|
int q, r;
|
|
|
|
assert(netns_storage_socket);
|
|
assert(netns_storage_socket[0] >= 0);
|
|
assert(netns_storage_socket[1] >= 0);
|
|
assert(path);
|
|
|
|
/* If the storage socket doesn't contain a netns fd yet, open one via the file system and store it in
|
|
* it. This is supposed to be called ahead of time, i.e. before setup_netns() which will allocate a
|
|
* new anonymous netns if needed. */
|
|
|
|
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. Open the file from the file system. */
|
|
|
|
netns = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
|
|
if (netns < 0) {
|
|
r = -errno;
|
|
goto fail;
|
|
}
|
|
|
|
r = fd_is_network_ns(netns);
|
|
if (r == 0) { /* Not a netns? Refuse early. */
|
|
r = -EINVAL;
|
|
goto fail;
|
|
}
|
|
if (r < 0 && r != -EUCLEAN) /* EUCLEAN: we don't know */
|
|
goto fail;
|
|
|
|
r = 1;
|
|
|
|
} else if (netns < 0) {
|
|
r = netns;
|
|
goto fail;
|
|
} else
|
|
r = 0; /* Already allocated */
|
|
|
|
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;
|
|
}
|
|
|
|
bool ns_type_supported(NamespaceType type) {
|
|
const char *t, *ns_proc;
|
|
|
|
t = namespace_type_to_string(type);
|
|
if (!t) /* Don't know how to translate this? Then it's not supported */
|
|
return false;
|
|
|
|
ns_proc = strjoina("/proc/self/ns/", t);
|
|
return access(ns_proc, F_OK) == 0;
|
|
}
|
|
|
|
static const char *const protect_home_table[_PROTECT_HOME_MAX] = {
|
|
[PROTECT_HOME_NO] = "no",
|
|
[PROTECT_HOME_YES] = "yes",
|
|
[PROTECT_HOME_READ_ONLY] = "read-only",
|
|
[PROTECT_HOME_TMPFS] = "tmpfs",
|
|
};
|
|
|
|
DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(protect_home, ProtectHome, PROTECT_HOME_YES);
|
|
|
|
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_WITH_BOOLEAN(protect_system, ProtectSystem, PROTECT_SYSTEM_YES);
|
|
|
|
static const char* const namespace_type_table[] = {
|
|
[NAMESPACE_MOUNT] = "mnt",
|
|
[NAMESPACE_CGROUP] = "cgroup",
|
|
[NAMESPACE_UTS] = "uts",
|
|
[NAMESPACE_IPC] = "ipc",
|
|
[NAMESPACE_USER] = "user",
|
|
[NAMESPACE_PID] = "pid",
|
|
[NAMESPACE_NET] = "net",
|
|
};
|
|
|
|
DEFINE_STRING_TABLE_LOOKUP(namespace_type, NamespaceType);
|
|
|
|
static const char* const protect_proc_table[_PROTECT_PROC_MAX] = {
|
|
[PROTECT_PROC_DEFAULT] = "default",
|
|
[PROTECT_PROC_NOACCESS] = "noaccess",
|
|
[PROTECT_PROC_INVISIBLE] = "invisible",
|
|
[PROTECT_PROC_PTRACEABLE] = "ptraceable",
|
|
};
|
|
|
|
DEFINE_STRING_TABLE_LOOKUP(protect_proc, ProtectProc);
|
|
|
|
static const char* const proc_subset_table[_PROC_SUBSET_MAX] = {
|
|
[PROC_SUBSET_ALL] = "all",
|
|
[PROC_SUBSET_PID] = "pid",
|
|
};
|
|
|
|
DEFINE_STRING_TABLE_LOOKUP(proc_subset, ProcSubset);
|