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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 15:35:18 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 15:35:18 +0000
commitb750101eb236130cf056c675997decbac904cc49 (patch)
treea5df1a06754bdd014cb975c051c83b01c9a97532 /src/core/namespace.c
parentInitial commit. (diff)
downloadsystemd-b750101eb236130cf056c675997decbac904cc49.tar.xz
systemd-b750101eb236130cf056c675997decbac904cc49.zip
Adding upstream version 252.22.upstream/252.22
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/core/namespace.c')
-rw-r--r--src/core/namespace.c3018
1 files changed, 3018 insertions, 0 deletions
diff --git a/src/core/namespace.c b/src/core/namespace.c
new file mode 100644
index 0000000..6870f70
--- /dev/null
+++ b/src/core/namespace.c
@@ -0,0 +1,3018 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <linux/loop.h>
+#include <sched.h>
+#include <stdio.h>
+#include <sys/file.h>
+#include <sys/mount.h>
+#include <unistd.h>
+#if WANT_LINUX_FS_H
+#include <linux/fs.h>
+#endif
+
+#include "alloc-util.h"
+#include "base-filesystem.h"
+#include "chase-symlinks.h"
+#include "dev-setup.h"
+#include "devnum-util.h"
+#include "env-util.h"
+#include "escape.h"
+#include "extension-release.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "glyph-util.h"
+#include "label.h"
+#include "list.h"
+#include "loop-util.h"
+#include "loopback-setup.h"
+#include "missing_syscall.h"
+#include "mkdir-label.h"
+#include "mount-util.h"
+#include "mountpoint-util.h"
+#include "namespace-util.h"
+#include "namespace.h"
+#include "nsflags.h"
+#include "nulstr-util.h"
+#include "os-util.h"
+#include "path-util.h"
+#include "selinux-util.h"
+#include "socket-util.h"
+#include "sort-util.h"
+#include "stat-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "tmpfile-util.h"
+#include "umask-util.h"
+#include "user-util.h"
+
+#define DEV_MOUNT_OPTIONS (MS_NOSUID|MS_STRICTATIME|MS_NOEXEC)
+
+typedef enum MountMode {
+ /* This is ordered by priority! */
+ INACCESSIBLE,
+ OVERLAY_MOUNT,
+ MOUNT_IMAGES,
+ BIND_MOUNT,
+ BIND_MOUNT_RECURSIVE,
+ PRIVATE_TMP,
+ PRIVATE_TMP_READONLY,
+ PRIVATE_DEV,
+ BIND_DEV,
+ EMPTY_DIR,
+ SYSFS,
+ PROCFS,
+ READONLY,
+ READWRITE,
+ NOEXEC,
+ EXEC,
+ TMPFS,
+ RUN,
+ EXTENSION_DIRECTORIES, /* Bind-mounted outside the root directory, and used by subsequent mounts */
+ EXTENSION_IMAGES, /* Mounted outside the root directory, and used by subsequent mounts */
+ MQUEUEFS,
+ READWRITE_IMPLICIT, /* Should have the lowest priority. */
+ _MOUNT_MODE_MAX,
+} MountMode;
+
+typedef struct MountEntry {
+ const char *path_const; /* Memory allocated on stack or static */
+ MountMode mode:5;
+ bool ignore:1; /* Ignore if path does not exist? */
+ bool has_prefix:1; /* Already is prefixed by the root dir? */
+ bool read_only:1; /* Shall this mount point be read-only? */
+ bool nosuid:1; /* Shall set MS_NOSUID on the mount itself */
+ bool noexec:1; /* Shall set MS_NOEXEC on the mount itself */
+ bool exec:1; /* Shall clear MS_NOEXEC on the mount itself */
+ bool applied:1; /* Already applied */
+ char *path_malloc; /* Use this instead of 'path_const' if we had to allocate memory */
+ const char *unprefixed_path_const; /* If the path was amended with a prefix, these will save the original */
+ char *unprefixed_path_malloc;
+ const char *source_const; /* The source path, for bind mounts or images */
+ char *source_malloc;
+ const char *options_const;/* Mount options for tmpfs */
+ char *options_malloc;
+ unsigned long flags; /* Mount flags used by EMPTY_DIR and TMPFS. Do not include MS_RDONLY here, but please use read_only. */
+ unsigned n_followed;
+ LIST_HEAD(MountOptions, image_options);
+} MountEntry;
+
+/* If MountAPIVFS= is used, let's mount /sys, /proc, /dev and /run into the it, but only as a fallback if the user hasn't mounted
+ * something there already. These mounts are hence overridden by any other explicitly configured mounts. */
+static const MountEntry apivfs_table[] = {
+ { "/proc", PROCFS, false },
+ { "/dev", BIND_DEV, false },
+ { "/sys", SYSFS, false },
+ { "/run", RUN, false, .options_const = "mode=755" TMPFS_LIMITS_RUN, .flags = MS_NOSUID|MS_NODEV|MS_STRICTATIME },
+};
+
+/* ProtectKernelTunables= option and the related filesystem APIs */
+static const MountEntry protect_kernel_tunables_proc_table[] = {
+ { "/proc/acpi", READONLY, true },
+ { "/proc/apm", READONLY, true }, /* Obsolete API, there's no point in permitting access to this, ever */
+ { "/proc/asound", READONLY, true },
+ { "/proc/bus", READONLY, true },
+ { "/proc/fs", READONLY, true },
+ { "/proc/irq", READONLY, true },
+ { "/proc/kallsyms", INACCESSIBLE, true },
+ { "/proc/kcore", INACCESSIBLE, true },
+ { "/proc/latency_stats", READONLY, true },
+ { "/proc/mtrr", READONLY, true },
+ { "/proc/scsi", READONLY, true },
+ { "/proc/sys", READONLY, true },
+ { "/proc/sysrq-trigger", READONLY, true },
+ { "/proc/timer_stats", READONLY, true },
+};
+
+static const MountEntry protect_kernel_tunables_sys_table[] = {
+ { "/sys", READONLY, false },
+ { "/sys/fs/bpf", READONLY, true },
+ { "/sys/fs/cgroup", READWRITE_IMPLICIT, false }, /* READONLY is set by ProtectControlGroups= option */
+ { "/sys/fs/selinux", READWRITE_IMPLICIT, true },
+ { "/sys/kernel/debug", READONLY, true },
+ { "/sys/kernel/tracing", READONLY, true },
+};
+
+/* ProtectKernelModules= option */
+static const MountEntry protect_kernel_modules_table[] = {
+#if HAVE_SPLIT_USR
+ { "/lib/modules", INACCESSIBLE, true },
+#endif
+ { "/usr/lib/modules", INACCESSIBLE, true },
+};
+
+/* ProtectKernelLogs= option */
+static const MountEntry protect_kernel_logs_proc_table[] = {
+ { "/proc/kmsg", INACCESSIBLE, true },
+};
+
+static const MountEntry protect_kernel_logs_dev_table[] = {
+ { "/dev/kmsg", INACCESSIBLE, true },
+};
+
+/*
+ * ProtectHome=read-only table, protect $HOME and $XDG_RUNTIME_DIR and rest of
+ * system should be protected by ProtectSystem=
+ */
+static const MountEntry protect_home_read_only_table[] = {
+ { "/home", READONLY, true },
+ { "/run/user", READONLY, true },
+ { "/root", READONLY, true },
+};
+
+/* ProtectHome=tmpfs table */
+static const MountEntry protect_home_tmpfs_table[] = {
+ { "/home", TMPFS, true, .read_only = true, .options_const = "mode=0755" TMPFS_LIMITS_EMPTY_OR_ALMOST, .flags = MS_NODEV|MS_STRICTATIME },
+ { "/run/user", TMPFS, true, .read_only = true, .options_const = "mode=0755" TMPFS_LIMITS_EMPTY_OR_ALMOST, .flags = MS_NODEV|MS_STRICTATIME },
+ { "/root", TMPFS, true, .read_only = true, .options_const = "mode=0700" TMPFS_LIMITS_EMPTY_OR_ALMOST, .flags = MS_NODEV|MS_STRICTATIME },
+};
+
+/* ProtectHome=yes table */
+static const MountEntry protect_home_yes_table[] = {
+ { "/home", INACCESSIBLE, true },
+ { "/run/user", INACCESSIBLE, true },
+ { "/root", INACCESSIBLE, true },
+};
+
+/* ProtectSystem=yes table */
+static const MountEntry protect_system_yes_table[] = {
+ { "/usr", READONLY, false },
+ { "/boot", READONLY, true },
+ { "/efi", READONLY, true },
+#if HAVE_SPLIT_USR
+ { "/lib", READONLY, true },
+ { "/lib64", READONLY, true },
+ { "/bin", READONLY, true },
+# if HAVE_SPLIT_BIN
+ { "/sbin", READONLY, true },
+# endif
+#endif
+};
+
+/* ProtectSystem=full includes ProtectSystem=yes */
+static const MountEntry protect_system_full_table[] = {
+ { "/usr", READONLY, false },
+ { "/boot", READONLY, true },
+ { "/efi", READONLY, true },
+ { "/etc", READONLY, false },
+#if HAVE_SPLIT_USR
+ { "/lib", READONLY, true },
+ { "/lib64", READONLY, true },
+ { "/bin", READONLY, true },
+# if HAVE_SPLIT_BIN
+ { "/sbin", READONLY, true },
+# endif
+#endif
+};
+
+/*
+ * ProtectSystem=strict table. In this strict mode, we mount everything
+ * read-only, except for /proc, /dev, /sys which are the kernel API VFS,
+ * which are left writable, but PrivateDevices= + ProtectKernelTunables=
+ * protect those, and these options should be fully orthogonal.
+ * (And of course /home and friends are also left writable, as ProtectHome=
+ * shall manage those, orthogonally).
+ */
+static const MountEntry protect_system_strict_table[] = {
+ { "/", READONLY, false },
+ { "/proc", READWRITE_IMPLICIT, false }, /* ProtectKernelTunables= */
+ { "/sys", READWRITE_IMPLICIT, false }, /* ProtectKernelTunables= */
+ { "/dev", READWRITE_IMPLICIT, false }, /* PrivateDevices= */
+ { "/home", READWRITE_IMPLICIT, true }, /* ProtectHome= */
+ { "/run/user", READWRITE_IMPLICIT, true }, /* ProtectHome= */
+ { "/root", READWRITE_IMPLICIT, true }, /* ProtectHome= */
+};
+
+static const char * const mount_mode_table[_MOUNT_MODE_MAX] = {
+ [INACCESSIBLE] = "inaccessible",
+ [OVERLAY_MOUNT] = "overlay",
+ [BIND_MOUNT] = "bind",
+ [BIND_MOUNT_RECURSIVE] = "rbind",
+ [PRIVATE_TMP] = "private-tmp",
+ [PRIVATE_DEV] = "private-dev",
+ [BIND_DEV] = "bind-dev",
+ [EMPTY_DIR] = "empty",
+ [SYSFS] = "sysfs",
+ [PROCFS] = "procfs",
+ [READONLY] = "read-only",
+ [READWRITE] = "read-write",
+ [TMPFS] = "tmpfs",
+ [MOUNT_IMAGES] = "mount-images",
+ [READWRITE_IMPLICIT] = "rw-implicit",
+ [EXEC] = "exec",
+ [NOEXEC] = "noexec",
+ [MQUEUEFS] = "mqueuefs",
+};
+
+DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(mount_mode, MountMode);
+
+static const char *mount_entry_path(const MountEntry *p) {
+ assert(p);
+
+ /* Returns the path of this bind mount. If the malloc()-allocated ->path_buffer field is set we return that,
+ * otherwise the stack/static ->path field is returned. */
+
+ return p->path_malloc ?: p->path_const;
+}
+
+static const char *mount_entry_unprefixed_path(const MountEntry *p) {
+ assert(p);
+
+ /* Returns the unprefixed path (ie: before prefix_where_needed() ran), if any */
+
+ return p->unprefixed_path_malloc ?: p->unprefixed_path_const ?: mount_entry_path(p);
+}
+
+static void mount_entry_consume_prefix(MountEntry *p, char *new_path) {
+ assert(p);
+ assert(p->path_malloc || p->path_const);
+ assert(new_path);
+
+ /* Saves current path in unprefixed_ variable, and takes over new_path */
+
+ free_and_replace(p->unprefixed_path_malloc, p->path_malloc);
+ /* If we didn't have a path on the heap, then it's a static one */
+ if (!p->unprefixed_path_malloc)
+ p->unprefixed_path_const = p->path_const;
+ p->path_malloc = new_path;
+ p->has_prefix = true;
+}
+
+static bool mount_entry_read_only(const MountEntry *p) {
+ assert(p);
+
+ return p->read_only || IN_SET(p->mode, READONLY, INACCESSIBLE, PRIVATE_TMP_READONLY);
+}
+
+static bool mount_entry_noexec(const MountEntry *p) {
+ assert(p);
+
+ return p->noexec || IN_SET(p->mode, NOEXEC, INACCESSIBLE, SYSFS, PROCFS);
+}
+
+static bool mount_entry_exec(const MountEntry *p) {
+ assert(p);
+
+ return p->exec || p->mode == EXEC;
+}
+
+static const char *mount_entry_source(const MountEntry *p) {
+ assert(p);
+
+ return p->source_malloc ?: p->source_const;
+}
+
+static const char *mount_entry_options(const MountEntry *p) {
+ assert(p);
+
+ return p->options_malloc ?: p->options_const;
+}
+
+static void mount_entry_done(MountEntry *p) {
+ assert(p);
+
+ p->path_malloc = mfree(p->path_malloc);
+ p->unprefixed_path_malloc = mfree(p->unprefixed_path_malloc);
+ p->source_malloc = mfree(p->source_malloc);
+ p->options_malloc = mfree(p->options_malloc);
+ p->image_options = mount_options_free_all(p->image_options);
+}
+
+static int append_access_mounts(MountEntry **p, char **strv, MountMode mode, bool forcibly_require_prefix) {
+ assert(p);
+
+ /* Adds a list of user-supplied READWRITE/READWRITE_IMPLICIT/READONLY/INACCESSIBLE entries */
+
+ STRV_FOREACH(i, strv) {
+ bool ignore = false, needs_prefix = false;
+ const char *e = *i;
+
+ /* Look for any prefixes */
+ if (startswith(e, "-")) {
+ e++;
+ ignore = true;
+ }
+ if (startswith(e, "+")) {
+ e++;
+ needs_prefix = true;
+ }
+
+ if (!path_is_absolute(e))
+ return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+ "Path is not absolute: %s", e);
+
+ *((*p)++) = (MountEntry) {
+ .path_const = e,
+ .mode = mode,
+ .ignore = ignore,
+ .has_prefix = !needs_prefix && !forcibly_require_prefix,
+ };
+ }
+
+ return 0;
+}
+
+static int append_empty_dir_mounts(MountEntry **p, char **strv) {
+ assert(p);
+
+ /* Adds tmpfs mounts to provide readable but empty directories. This is primarily used to implement the
+ * "/private/" boundary directories for DynamicUser=1. */
+
+ STRV_FOREACH(i, strv) {
+
+ *((*p)++) = (MountEntry) {
+ .path_const = *i,
+ .mode = EMPTY_DIR,
+ .ignore = false,
+ .read_only = true,
+ .options_const = "mode=755" TMPFS_LIMITS_EMPTY_OR_ALMOST,
+ .flags = MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME,
+ };
+ }
+
+ return 0;
+}
+
+static int append_bind_mounts(MountEntry **p, const BindMount *binds, size_t n) {
+ assert(p);
+
+ for (size_t i = 0; i < n; i++) {
+ const BindMount *b = binds + i;
+
+ *((*p)++) = (MountEntry) {
+ .path_const = b->destination,
+ .mode = b->recursive ? BIND_MOUNT_RECURSIVE : BIND_MOUNT,
+ .read_only = b->read_only,
+ .nosuid = b->nosuid,
+ .source_const = b->source,
+ .ignore = b->ignore_enoent,
+ };
+ }
+
+ return 0;
+}
+
+static int append_mount_images(MountEntry **p, const MountImage *mount_images, size_t n) {
+ assert(p);
+
+ for (size_t i = 0; i < n; i++) {
+ const MountImage *m = mount_images + i;
+
+ *((*p)++) = (MountEntry) {
+ .path_const = m->destination,
+ .mode = MOUNT_IMAGES,
+ .source_const = m->source,
+ .image_options = m->mount_options,
+ .ignore = m->ignore_enoent,
+ };
+ }
+
+ return 0;
+}
+
+static int append_extensions(
+ MountEntry **p,
+ const char *root,
+ const char *extension_dir,
+ char **hierarchies,
+ const MountImage *mount_images,
+ size_t n,
+ char **extension_directories) {
+
+ _cleanup_strv_free_ char **overlays = NULL;
+ int r;
+
+ if (n == 0 && strv_isempty(extension_directories))
+ return 0;
+
+ assert(p);
+ assert(extension_dir);
+
+ /* Prepare a list of overlays, that will have as each element a string suitable for being
+ * passed as a lowerdir= parameter, so start with the hierarchy on the root.
+ * The overlays vector will have the same number of elements and will correspond to the
+ * hierarchies vector, so they can be iterated upon together. */
+ STRV_FOREACH(hierarchy, hierarchies) {
+ _cleanup_free_ char *prefixed_hierarchy = NULL;
+
+ prefixed_hierarchy = path_join(root, *hierarchy);
+ if (!prefixed_hierarchy)
+ return -ENOMEM;
+
+ r = strv_consume(&overlays, TAKE_PTR(prefixed_hierarchy));
+ if (r < 0)
+ return r;
+ }
+
+ /* First, prepare a mount for each image, but these won't be visible to the unit, instead
+ * they will be mounted in our propagate directory, and used as a source for the overlay. */
+ for (size_t i = 0; i < n; i++) {
+ _cleanup_free_ char *mount_point = NULL;
+ const MountImage *m = mount_images + i;
+
+ r = asprintf(&mount_point, "%s/%zu", extension_dir, i);
+ if (r < 0)
+ return -ENOMEM;
+
+ for (size_t j = 0; hierarchies && hierarchies[j]; ++j) {
+ _cleanup_free_ char *prefixed_hierarchy = NULL, *escaped = NULL, *lowerdir = NULL;
+
+ prefixed_hierarchy = path_join(mount_point, hierarchies[j]);
+ if (!prefixed_hierarchy)
+ return -ENOMEM;
+
+ escaped = shell_escape(prefixed_hierarchy, ",:");
+ if (!escaped)
+ return -ENOMEM;
+
+ /* Note that lowerdir= parameters are in 'reverse' order, so the
+ * top-most directory in the overlay comes first in the list. */
+ lowerdir = strjoin(escaped, ":", overlays[j]);
+ if (!lowerdir)
+ return -ENOMEM;
+
+ free_and_replace(overlays[j], lowerdir);
+ }
+
+ *((*p)++) = (MountEntry) {
+ .path_malloc = TAKE_PTR(mount_point),
+ .image_options = m->mount_options,
+ .ignore = m->ignore_enoent,
+ .source_const = m->source,
+ .mode = EXTENSION_IMAGES,
+ .has_prefix = true,
+ };
+ }
+
+ /* Secondly, extend the lowerdir= parameters with each ExtensionDirectory.
+ * Bind mount them in the same location as the ExtensionImages, so that we
+ * can check that they are valid trees (extension-release.d). */
+ STRV_FOREACH(extension_directory, extension_directories) {
+ _cleanup_free_ char *mount_point = NULL, *source = NULL;
+ const char *e = *extension_directory;
+ bool ignore_enoent = false;
+
+ /* Pick up the counter where the ExtensionImages left it. */
+ r = asprintf(&mount_point, "%s/%zu", extension_dir, n++);
+ if (r < 0)
+ return -ENOMEM;
+
+ /* Look for any prefixes */
+ if (startswith(e, "-")) {
+ e++;
+ ignore_enoent = true;
+ }
+ /* Ignore this for now */
+ if (startswith(e, "+"))
+ e++;
+
+ source = strdup(e);
+ if (!source)
+ return -ENOMEM;
+
+ for (size_t j = 0; hierarchies && hierarchies[j]; ++j) {
+ _cleanup_free_ char *prefixed_hierarchy = NULL, *escaped = NULL, *lowerdir = NULL;
+
+ prefixed_hierarchy = path_join(mount_point, hierarchies[j]);
+ if (!prefixed_hierarchy)
+ return -ENOMEM;
+
+ escaped = shell_escape(prefixed_hierarchy, ",:");
+ if (!escaped)
+ return -ENOMEM;
+
+ /* Note that lowerdir= parameters are in 'reverse' order, so the
+ * top-most directory in the overlay comes first in the list. */
+ lowerdir = strjoin(escaped, ":", overlays[j]);
+ if (!lowerdir)
+ return -ENOMEM;
+
+ free_and_replace(overlays[j], lowerdir);
+ }
+
+ *((*p)++) = (MountEntry) {
+ .path_malloc = TAKE_PTR(mount_point),
+ .source_malloc = TAKE_PTR(source),
+ .mode = EXTENSION_DIRECTORIES,
+ .ignore = ignore_enoent,
+ .has_prefix = true,
+ .read_only = true,
+ };
+ }
+
+ /* Then, for each hierarchy, prepare an overlay with the list of lowerdir= strings
+ * set up earlier. */
+ for (size_t i = 0; hierarchies && hierarchies[i]; ++i) {
+ _cleanup_free_ char *prefixed_hierarchy = NULL;
+
+ prefixed_hierarchy = path_join(root, hierarchies[i]);
+ if (!prefixed_hierarchy)
+ return -ENOMEM;
+
+ *((*p)++) = (MountEntry) {
+ .path_malloc = TAKE_PTR(prefixed_hierarchy),
+ .options_malloc = TAKE_PTR(overlays[i]),
+ .mode = OVERLAY_MOUNT,
+ .has_prefix = true,
+ .ignore = true, /* If the source image doesn't set the ignore bit it will fail earlier. */
+ };
+ }
+
+ return 0;
+}
+
+static int append_tmpfs_mounts(MountEntry **p, const TemporaryFileSystem *tmpfs, size_t n) {
+ assert(p);
+
+ for (size_t i = 0; i < n; i++) {
+ const TemporaryFileSystem *t = tmpfs + i;
+ _cleanup_free_ char *o = NULL, *str = NULL;
+ unsigned long flags;
+ bool ro = false;
+ int r;
+
+ if (!path_is_absolute(t->path))
+ return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+ "Path is not absolute: %s",
+ t->path);
+
+ str = strjoin("mode=0755" NESTED_TMPFS_LIMITS ",", t->options);
+ if (!str)
+ return -ENOMEM;
+
+ r = mount_option_mangle(str, MS_NODEV|MS_STRICTATIME, &flags, &o);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to parse mount option '%s': %m", str);
+
+ ro = flags & MS_RDONLY;
+ if (ro)
+ flags ^= MS_RDONLY;
+
+ *((*p)++) = (MountEntry) {
+ .path_const = t->path,
+ .mode = TMPFS,
+ .read_only = ro,
+ .options_malloc = TAKE_PTR(o),
+ .flags = flags,
+ };
+ }
+
+ return 0;
+}
+
+static int append_static_mounts(MountEntry **p, const MountEntry *mounts, size_t n, bool ignore_protect) {
+ assert(p);
+ assert(mounts);
+
+ /* Adds a list of static pre-defined entries */
+
+ for (size_t i = 0; i < n; i++)
+ *((*p)++) = (MountEntry) {
+ .path_const = mount_entry_path(mounts+i),
+ .mode = mounts[i].mode,
+ .ignore = mounts[i].ignore || ignore_protect,
+ };
+
+ return 0;
+}
+
+static int append_protect_home(MountEntry **p, ProtectHome protect_home, bool ignore_protect) {
+ assert(p);
+
+ switch (protect_home) {
+
+ case PROTECT_HOME_NO:
+ return 0;
+
+ case PROTECT_HOME_READ_ONLY:
+ return append_static_mounts(p, protect_home_read_only_table, ELEMENTSOF(protect_home_read_only_table), ignore_protect);
+
+ case PROTECT_HOME_TMPFS:
+ return append_static_mounts(p, protect_home_tmpfs_table, ELEMENTSOF(protect_home_tmpfs_table), ignore_protect);
+
+ case PROTECT_HOME_YES:
+ return append_static_mounts(p, protect_home_yes_table, ELEMENTSOF(protect_home_yes_table), ignore_protect);
+
+ default:
+ assert_not_reached();
+ }
+}
+
+static int append_protect_system(MountEntry **p, ProtectSystem protect_system, bool ignore_protect) {
+ assert(p);
+
+ switch (protect_system) {
+
+ case PROTECT_SYSTEM_NO:
+ return 0;
+
+ case PROTECT_SYSTEM_STRICT:
+ return append_static_mounts(p, protect_system_strict_table, ELEMENTSOF(protect_system_strict_table), ignore_protect);
+
+ case PROTECT_SYSTEM_YES:
+ return append_static_mounts(p, protect_system_yes_table, ELEMENTSOF(protect_system_yes_table), ignore_protect);
+
+ case PROTECT_SYSTEM_FULL:
+ return append_static_mounts(p, protect_system_full_table, ELEMENTSOF(protect_system_full_table), ignore_protect);
+
+ default:
+ assert_not_reached();
+ }
+}
+
+static int mount_path_compare(const MountEntry *a, const MountEntry *b) {
+ int d;
+
+ /* ExtensionImages/Directories will be used by other mounts as a base, so sort them first
+ * regardless of the prefix - they are set up in the propagate directory anyway */
+ d = -CMP(a->mode == EXTENSION_IMAGES, b->mode == EXTENSION_IMAGES);
+ if (d != 0)
+ return d;
+ d = -CMP(a->mode == EXTENSION_DIRECTORIES, b->mode == EXTENSION_DIRECTORIES);
+ if (d != 0)
+ return d;
+
+ /* If the paths are not equal, then order prefixes first */
+ d = path_compare(mount_entry_path(a), mount_entry_path(b));
+ if (d != 0)
+ return d;
+
+ /* If the paths are equal, check the mode */
+ return CMP((int) a->mode, (int) b->mode);
+}
+
+static int prefix_where_needed(MountEntry *m, size_t n, const char *root_directory) {
+ /* Prefixes all paths in the bind mount table with the root directory if the entry needs that. */
+
+ assert(m || n == 0);
+
+ for (size_t i = 0; i < n; i++) {
+ char *s;
+
+ if (m[i].has_prefix)
+ continue;
+
+ s = path_join(root_directory, mount_entry_path(m+i));
+ if (!s)
+ return -ENOMEM;
+
+ mount_entry_consume_prefix(&m[i], s);
+ }
+
+ return 0;
+}
+
+static void drop_duplicates(MountEntry *m, size_t *n) {
+ MountEntry *f, *t, *previous;
+
+ assert(m);
+ assert(n);
+
+ /* Drops duplicate entries. Expects that the array is properly ordered already. */
+
+ 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));
+ /* Propagate the flags to the remaining entry */
+ previous->read_only = previous->read_only || mount_entry_read_only(f);
+ previous->noexec = previous->noexec || mount_entry_noexec(f);
+ previous->exec = previous->exec || mount_entry_exec(f);
+ 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 *found = NULL;
+
+ /* Now let's find the first parent of the entry we are looking at. */
+ for (MountEntry *p = PTR_SUB1(t, m); p; p = PTR_SUB1(p, m))
+ if (path_startswith(mount_entry_path(f), mount_entry_path(p))) {
+ found = p;
+ break;
+ }
+
+ /* We found it, let's see if it's the same mode, if so, we can drop this entry */
+ if (found && found->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(found), mount_mode_to_string(found->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++) {
+
+ /* ExtensionImages/Directories bases are opened in /run/systemd/unit-extensions on the host */
+ if (!IN_SET(f->mode, EXTENSION_IMAGES, EXTENSION_DIRECTORIES) && !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/" DEVNUM_FORMAT_STR,
+ temporary_mount,
+ S_ISCHR(st.st_mode) ? "char" : "block",
+ DEVNUM_FORMAT_VAL(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;
+ int r;
+
+ assert(m);
+
+ 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_PRIVATE_DEV);
+ if (r < 0)
+ goto fail;
+
+ r = label_fix_full(AT_FDCWD, dev, "/dev", 0);
+ if (r < 0) {
+ log_debug_errno(r, "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 bool mount_option_supported(const char *fstype, const char *key, const char *value) {
+ _cleanup_close_ int fd = -1;
+ int r;
+
+ /* This function assumes support by default. Only if the fsconfig() call fails with -EINVAL/-EOPNOTSUPP
+ * will it report that the option/value is not supported. */
+
+ fd = fsopen(fstype, FSOPEN_CLOEXEC);
+ if (fd < 0) {
+ if (errno != ENOSYS)
+ log_debug_errno(errno, "Failed to open superblock context for '%s': %m", fstype);
+ return true; /* If fsopen() fails for whatever reason, assume the value is supported. */
+ }
+
+ r = fsconfig(fd, FSCONFIG_SET_STRING, key, value, 0);
+ if (r < 0 && !IN_SET(errno, EINVAL, EOPNOTSUPP, ENOSYS))
+ log_debug_errno(errno, "Failed to set '%s=%s' on '%s' superblock context: %m", key, value, fstype);
+
+ return r >= 0 || !IN_SET(errno, EINVAL, EOPNOTSUPP);
+}
+
+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. */
+
+ const char *hpv = ns_info->protect_proc == PROTECT_PROC_DEFAULT ?
+ "off" :
+ protect_proc_to_string(ns_info->protect_proc);
+
+ /* hidepid= support was added in 5.8, so we can use fsconfig()/fsopen() (which were added in
+ * 5.2) to check if hidepid= is supported. This avoids a noisy dmesg log by the kernel when
+ * trying to use hidepid= on systems where it isn't supported. The same applies for subset=.
+ * fsopen()/fsconfig() was also backported on some distros which allows us to detect
+ * hidepid=/subset= support in even more scenarios. */
+
+ if (mount_option_supported("proc", "hidepid", hpv)) {
+ opts = strjoin("hidepid=", hpv);
+ if (!opts)
+ return -ENOMEM;
+ }
+
+ if (ns_info->proc_subset == PROC_SUBSET_PID && mount_option_supported("proc", "subset", "pid"))
+ if (!strextend_with_separator(&opts, ",", "subset=pid"))
+ 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) {
+ /* We lack permissions to mount a new instance of /proc, and it is not already
+ * mounted. But we can access the host's, so as a final fallback bind-mount it to
+ * the destination, as most likely we are inside a user manager in an unprivileged
+ * user namespace. */
+ r = mount_nofollow_verbose(LOG_DEBUG, "/proc", entry_path, NULL, MS_BIND|MS_REC, NULL);
+ if (r < 0)
+ 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 = mount_entry_unprefixed_path(m);
+
+ /* 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_full(AT_FDCWD, 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_run(const MountEntry *m) {
+ int r;
+
+ assert(m);
+
+ r = path_is_mount_point(mount_entry_path(m), NULL, 0);
+ if (r < 0 && r != -ENOENT)
+ return log_debug_errno(r, "Unable to determine whether /run is already mounted: %m");
+ if (r > 0) /* make this a NOP if /run is already a mount point */
+ return 0;
+
+ return mount_tmpfs(m);
+}
+
+static int mount_mqueuefs(const MountEntry *m) {
+ int r;
+ const char *entry_path;
+
+ assert(m);
+
+ entry_path = mount_entry_path(m);
+
+ (void) mkdir_p_label(entry_path, 0755);
+ (void) umount_recursive(entry_path, 0);
+
+ r = mount_nofollow_verbose(LOG_DEBUG, "mqueue", entry_path, "mqueue", m->flags, mount_entry_options(m));
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static int mount_image(const MountEntry *m, const char *root_directory) {
+
+ _cleanup_free_ char *host_os_release_id = NULL, *host_os_release_version_id = NULL,
+ *host_os_release_sysext_level = NULL;
+ int r;
+
+ assert(m);
+
+ if (m->mode == EXTENSION_IMAGES) {
+ r = parse_os_release(
+ empty_to_root(root_directory),
+ "ID", &host_os_release_id,
+ "VERSION_ID", &host_os_release_version_id,
+ "SYSEXT_LEVEL", &host_os_release_sysext_level,
+ NULL);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to acquire 'os-release' data of OS tree '%s': %m", empty_to_root(root_directory));
+ if (isempty(host_os_release_id))
+ return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "'ID' field not found or empty in 'os-release' data of OS tree '%s': %m", empty_to_root(root_directory));
+ }
+
+ r = verity_dissect_and_mount(
+ /* src_fd= */ -1, mount_entry_source(m), mount_entry_path(m), m->image_options,
+ host_os_release_id, host_os_release_version_id, host_os_release_sysext_level, NULL);
+ if (r == -ENOENT && m->ignore)
+ return 0;
+ if (r == -ESTALE && host_os_release_id)
+ return log_error_errno(r,
+ "Failed to mount image %s, extension-release metadata does not match the lower layer's: ID=%s%s%s%s%s",
+ mount_entry_source(m),
+ host_os_release_id,
+ host_os_release_version_id ? " VERSION_ID=" : "",
+ strempty(host_os_release_version_id),
+ host_os_release_sysext_level ? " SYSEXT_LEVEL=" : "",
+ strempty(host_os_release_sysext_level));
+ if (r < 0)
+ return log_debug_errno(r, "Failed to mount image %s on %s: %m", mount_entry_source(m), mount_entry_path(m));
+
+ return 1;
+}
+
+static int mount_overlay(const MountEntry *m) {
+ const char *options;
+ int r;
+
+ assert(m);
+
+ options = strjoina("lowerdir=", mount_entry_options(m));
+
+ (void) mkdir_p_label(mount_entry_path(m), 0755);
+
+ r = mount_nofollow_verbose(LOG_DEBUG, "overlay", mount_entry_path(m), "overlay", MS_RDONLY, options);
+ if (r == -ENOENT && m->ignore)
+ return 0;
+ if (r < 0)
+ return r;
+
+ 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 %s.",
+ mount_entry_path(m), special_glyph(SPECIAL_GLYPH_ARROW_RIGHT), target);
+
+ mount_entry_consume_prefix(m, TAKE_PTR(target));
+
+ m->n_followed ++;
+
+ return 0;
+}
+
+static int apply_one_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:
+ case EXEC:
+ case NOEXEC:
+ 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
+ * and MS_NOEXEC bits 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 EXTENSION_DIRECTORIES: {
+ _cleanup_free_ char *host_os_release_id = NULL, *host_os_release_version_id = NULL,
+ *host_os_release_sysext_level = NULL, *extension_name = NULL;
+ _cleanup_strv_free_ char **extension_release = NULL;
+
+ r = path_extract_filename(mount_entry_source(m), &extension_name);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to extract extension name from %s: %m", mount_entry_source(m));
+
+ r = parse_os_release(
+ empty_to_root(root_directory),
+ "ID", &host_os_release_id,
+ "VERSION_ID", &host_os_release_version_id,
+ "SYSEXT_LEVEL", &host_os_release_sysext_level,
+ NULL);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to acquire 'os-release' data of OS tree '%s': %m", empty_to_root(root_directory));
+ if (isempty(host_os_release_id))
+ return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "'ID' field not found or empty in 'os-release' data of OS tree '%s': %m", empty_to_root(root_directory));
+
+ r = load_extension_release_pairs(mount_entry_source(m), extension_name, /* relax_extension_release_check= */ false, &extension_release);
+ if (r == -ENOENT && m->ignore)
+ return 0;
+ if (r < 0)
+ return log_debug_errno(r, "Failed to parse directory %s extension-release metadata: %m", extension_name);
+
+ r = extension_release_validate(
+ extension_name,
+ host_os_release_id,
+ host_os_release_version_id,
+ host_os_release_sysext_level,
+ /* host_sysext_scope */ NULL, /* Leave empty, we need to accept both system and portable */
+ extension_release);
+ if (r == 0)
+ return log_debug_errno(SYNTHETIC_ERRNO(ESTALE), "Directory %s extension-release metadata does not match the root's", extension_name);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to compare directory %s extension-release metadata with the root's os-release: %m", extension_name);
+
+ _fallthrough_;
+ }
+
+ 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 %s.",
+ mount_entry_source(m), special_glyph(SPECIAL_GLYPH_ARROW_RIGHT), 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 RUN:
+ return mount_run(m);
+
+ case MQUEUEFS:
+ return mount_mqueuefs(m);
+
+ case MOUNT_IMAGES:
+ return mount_image(m, NULL);
+
+ case EXTENSION_IMAGES:
+ return mount_image(m, root_directory);
+
+ case OVERLAY_MOUNT:
+ return mount_overlay(m);
+
+ default:
+ assert_not_reached();
+ }
+
+ 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 && q != -EEXIST)
+ 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;
+ int r;
+
+ 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);
+
+ /* Note 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 int make_noexec(const MountEntry *m, char **deny_list, FILE *proc_self_mountinfo) {
+ unsigned long new_flags = 0, flags_mask = 0;
+ bool submounts;
+ int r;
+
+ assert(m);
+ assert(proc_self_mountinfo);
+
+ if (mount_entry_noexec(m)) {
+ new_flags |= MS_NOEXEC;
+ flags_mask |= MS_NOEXEC;
+ } else if (mount_entry_exec(m)) {
+ new_flags &= ~MS_NOEXEC;
+ flags_mask |= MS_NOEXEC;
+ }
+
+ if (flags_mask == 0) /* No Change? */
+ return 0;
+
+ submounts = !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);
+
+ 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 int make_nosuid(const MountEntry *m, FILE *proc_self_mountinfo) {
+ bool submounts;
+ int r;
+
+ assert(m);
+ assert(proc_self_mountinfo);
+
+ submounts = !IN_SET(m->mode, EMPTY_DIR, TMPFS);
+
+ if (submounts)
+ r = bind_remount_recursive_with_mountinfo(mount_entry_path(m), MS_NOSUID, MS_NOSUID, NULL, proc_self_mountinfo);
+ else
+ r = bind_remount_one_with_mountinfo(mount_entry_path(m), MS_NOSUID, MS_NOSUID, proc_self_mountinfo);
+ 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** exec_paths,
+ char** no_exec_paths,
+ char** empty_directories,
+ size_t n_bind_mounts,
+ size_t n_temporary_filesystems,
+ size_t n_mount_images,
+ size_t n_extension_images,
+ size_t n_extension_directories,
+ size_t n_hierarchies,
+ const char* tmp_dir,
+ const char* var_tmp_dir,
+ const char *creds_path,
+ const char* log_namespace,
+ bool setup_propagate,
+ const char* notify_socket) {
+
+ 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(exec_paths) +
+ strv_length(no_exec_paths) +
+ strv_length(empty_directories) +
+ n_bind_mounts +
+ n_mount_images +
+ (n_extension_images > 0 || n_extension_directories > 0 ? /* Mount each image and directory plus an overlay per hierarchy */
+ n_hierarchies + n_extension_images + n_extension_directories: 0) +
+ n_temporary_filesystems +
+ ns_info->private_dev +
+ (ns_info->protect_kernel_tunables ?
+ ELEMENTSOF(protect_kernel_tunables_proc_table) + ELEMENTSOF(protect_kernel_tunables_sys_table) : 0) +
+ (ns_info->protect_kernel_modules ? ELEMENTSOF(protect_kernel_modules_table) : 0) +
+ (ns_info->protect_kernel_logs ?
+ ELEMENTSOF(protect_kernel_logs_proc_table) + ELEMENTSOF(protect_kernel_logs_dev_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 +
+ setup_propagate + /* /run/systemd/incoming */
+ !!notify_socket +
+ ns_info->private_ipc; /* /dev/mqueue */
+}
+
+/* Walk all mount entries and dropping any unused mounts. This affects all
+ * mounts:
+ * - that are implicitly protected by a path that has been rendered inaccessible
+ * - whose immediate parent requests the same protection mode as the mount itself
+ * - that are outside of the relevant root directory
+ * - which are duplicates
+ */
+static void drop_unused_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 int create_symlinks_from_tuples(const char *root, char **strv_symlinks) {
+ int r;
+
+ STRV_FOREACH_PAIR(src, dst, strv_symlinks) {
+ _cleanup_free_ char *src_abs = NULL, *dst_abs = NULL;
+
+ src_abs = path_join(root, *src);
+ dst_abs = path_join(root, *dst);
+ if (!src_abs || !dst_abs)
+ return -ENOMEM;
+
+ r = mkdir_parents_label(dst_abs, 0755);
+ if (r < 0)
+ return log_debug_errno(
+ r,
+ "Failed to create parent directory for symlink '%s': %m",
+ dst_abs);
+
+ r = symlink_idempotent(src_abs, dst_abs, true);
+ if (r < 0)
+ return log_debug_errno(
+ r,
+ "Failed to create symlink from '%s' to '%s': %m",
+ src_abs,
+ dst_abs);
+ }
+
+ return 0;
+}
+
+static int apply_mounts(
+ const char *root,
+ const NamespaceInfo *ns_info,
+ MountEntry *mounts,
+ size_t *n_mounts,
+ char **exec_dir_symlinks,
+ char **error_path) {
+
+ _cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
+ _cleanup_free_ char **deny_list = NULL;
+ int r;
+
+ if (n_mounts == 0) /* Shortcut: nothing to do */
+ return 0;
+
+ assert(root);
+ assert(mounts);
+ assert(n_mounts);
+
+ /* 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 = -errno;
+
+ if (error_path)
+ *error_path = strdup("/proc/self/mountinfo");
+
+ return log_debug_errno(r, "Failed to open /proc/self/mountinfo: %m");
+ }
+
+ /* First round, establish all mounts we need */
+ for (;;) {
+ bool again = false;
+
+ for (MountEntry *m = mounts; m < mounts + *n_mounts; ++m) {
+
+ if (m->applied)
+ continue;
+
+ /* ExtensionImages/Directories are first opened in the propagate directory, not in the root_directory */
+ r = follow_symlink(!IN_SET(m->mode, EXTENSION_IMAGES, EXTENSION_DIRECTORIES) ? root : NULL, m);
+ if (r < 0) {
+ if (error_path && mount_entry_path(m))
+ *error_path = strdup(mount_entry_path(m));
+ return r;
+ }
+ 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_one_mount(root, m, ns_info);
+ if (r < 0) {
+ if (error_path && mount_entry_path(m))
+ *error_path = strdup(mount_entry_path(m));
+ return r;
+ }
+
+ m->applied = true;
+ }
+
+ if (!again)
+ break;
+
+ drop_unused_mounts(root, mounts, n_mounts);
+ }
+
+ /* Now that all filesystems have been set up, but before the
+ * read-only switches are flipped, create the exec dirs symlinks.
+ * Note that when /var/lib is not empty/tmpfs, these symlinks will already
+ * exist, which means this will be a no-op. */
+ r = create_symlinks_from_tuples(root, exec_dir_symlinks);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to set up ExecDirectories symlinks inside mount namespace: %m");
+
+ /* Create a deny list we can pass to bind_mount_recursive() */
+ deny_list = new(char*, (*n_mounts)+1);
+ if (!deny_list)
+ return -ENOMEM;
+ for (size_t j = 0; j < *n_mounts; j++)
+ deny_list[j] = (char*) mount_entry_path(mounts+j);
+ deny_list[*n_mounts] = NULL;
+
+ /* Second round, flip the ro bits if necessary. */
+ for (MountEntry *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));
+ return r;
+ }
+ }
+
+ /* Third round, flip the noexec bits with a simplified deny list. */
+ for (size_t j = 0; j < *n_mounts; j++)
+ if (IN_SET((mounts+j)->mode, EXEC, NOEXEC))
+ deny_list[j] = (char*) mount_entry_path(mounts+j);
+ deny_list[*n_mounts] = NULL;
+
+ for (MountEntry *m = mounts; m < mounts + *n_mounts; ++m) {
+ r = make_noexec(m, deny_list, proc_self_mountinfo);
+ if (r < 0) {
+ if (error_path && mount_entry_path(m))
+ *error_path = strdup(mount_entry_path(m));
+ return r;
+ }
+ }
+
+ /* Fourth round, flip the nosuid bits without a deny list. */
+ if (ns_info->mount_nosuid)
+ for (MountEntry *m = mounts; m < mounts + *n_mounts; ++m) {
+ r = make_nosuid(m, proc_self_mountinfo);
+ if (r < 0) {
+ if (error_path && mount_entry_path(m))
+ *error_path = strdup(mount_entry_path(m));
+ return r;
+ }
+ }
+
+ return 1;
+}
+
+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) {
+
+ /* 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 (size_t 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 (size_t 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** exec_paths,
+ char** no_exec_paths,
+ char** empty_directories,
+ char** exec_dir_symlinks,
+ 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,
+ const MountImage *extension_images,
+ size_t n_extension_images,
+ char **extension_directories,
+ const char *propagate_dir,
+ const char *incoming_dir,
+ const char *extension_dir,
+ const char *notify_socket,
+ char **error_path) {
+
+ _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
+ _cleanup_(dissected_image_unrefp) DissectedImage *dissected_image = NULL;
+ _cleanup_(verity_settings_done) VeritySettings verity = VERITY_SETTINGS_DEFAULT;
+ _cleanup_strv_free_ char **hierarchies = NULL;
+ MountEntry *m = NULL, *mounts = NULL;
+ bool require_prefix = false, setup_propagate = false;
+ const char *root;
+ DissectImageFlags dissect_image_flags =
+ DISSECT_IMAGE_GENERIC_ROOT |
+ DISSECT_IMAGE_REQUIRE_ROOT |
+ DISSECT_IMAGE_DISCARD_ON_LOOP |
+ DISSECT_IMAGE_RELAX_VAR_CHECK |
+ DISSECT_IMAGE_FSCK |
+ DISSECT_IMAGE_USR_NO_ROOT |
+ DISSECT_IMAGE_GROWFS |
+ DISSECT_IMAGE_ADD_PARTITION_DEVICES |
+ DISSECT_IMAGE_PIN_PARTITION_DEVICES;
+ size_t n_mounts;
+ int r;
+
+ assert(ns_info);
+
+ /* Make sure that all mknod(), mkdir() calls we do are unaffected by the umask, and the access modes
+ * we configure take effect */
+ BLOCK_WITH_UMASK(0000);
+
+ if (!isempty(propagate_dir) && !isempty(incoming_dir))
+ setup_propagate = true;
+
+ if (mount_flags == 0)
+ mount_flags = MS_SHARED;
+
+ if (root_image) {
+ /* 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_DEVICE_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,
+ LOCK_SH,
+ &loop_device);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to create loop device for root image: %m");
+
+ r = dissect_loop_device(
+ loop_device,
+ &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_load_verity_sig_partition(
+ dissected_image,
+ loop_device->fd,
+ &verity);
+ if (r < 0)
+ return r;
+
+ r = dissected_image_decrypt(
+ dissected_image,
+ NULL,
+ &verity,
+ dissect_image_flags);
+ 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;
+ }
+
+ if (n_extension_images > 0 || !strv_isempty(extension_directories)) {
+ r = parse_env_extension_hierarchies(&hierarchies);
+ if (r < 0)
+ return r;
+ }
+
+ n_mounts = namespace_calculate_mounts(
+ ns_info,
+ read_write_paths,
+ read_only_paths,
+ inaccessible_paths,
+ exec_paths,
+ no_exec_paths,
+ empty_directories,
+ n_bind_mounts,
+ n_temporary_filesystems,
+ n_mount_images,
+ n_extension_images,
+ strv_length(extension_directories),
+ strv_length(hierarchies),
+ tmp_dir, var_tmp_dir,
+ creds_path,
+ log_namespace,
+ setup_propagate,
+ notify_socket);
+
+ 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_access_mounts(&m, exec_paths, EXEC, require_prefix);
+ if (r < 0)
+ goto finish;
+
+ r = append_access_mounts(&m, no_exec_paths, NOEXEC, 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;
+
+ r = append_extensions(&m, root, extension_dir, hierarchies, extension_images, n_extension_images, extension_directories);
+ if (r < 0)
+ goto finish;
+
+ if (ns_info->private_dev)
+ *(m++) = (MountEntry) {
+ .path_const = "/dev",
+ .mode = PRIVATE_DEV,
+ .flags = DEV_MOUNT_OPTIONS,
+ };
+
+ /* In case /proc is successfully mounted with pid tree subset only (ProcSubset=pid), the
+ protective mounts to non-pid /proc paths would fail. But the pid only option may have
+ failed gracefully, so let's try the mounts but it's not fatal if they don't succeed. */
+ bool ignore_protect_proc = ns_info->ignore_protect_paths || ns_info->proc_subset == PROC_SUBSET_PID;
+ if (ns_info->protect_kernel_tunables) {
+ r = append_static_mounts(&m,
+ protect_kernel_tunables_proc_table,
+ ELEMENTSOF(protect_kernel_tunables_proc_table),
+ ignore_protect_proc);
+ if (r < 0)
+ goto finish;
+
+ r = append_static_mounts(&m,
+ protect_kernel_tunables_sys_table,
+ ELEMENTSOF(protect_kernel_tunables_sys_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_proc_table,
+ ELEMENTSOF(protect_kernel_logs_proc_table),
+ ignore_protect_proc);
+ if (r < 0)
+ goto finish;
+
+ r = append_static_mounts(&m,
+ protect_kernel_logs_dev_table,
+ ELEMENTSOF(protect_kernel_logs_dev_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;
+ }
+
+ /* Note, if proc is mounted with subset=pid then neither of the
+ * two paths will exist, i.e. they are implicitly protected by
+ * the mount option. */
+ if (ns_info->protect_hostname) {
+ *(m++) = (MountEntry) {
+ .path_const = "/proc/sys/kernel/hostname",
+ .mode = READONLY,
+ .ignore = ignore_protect_proc,
+ };
+ *(m++) = (MountEntry) {
+ .path_const = "/proc/sys/kernel/domainname",
+ .mode = READONLY,
+ .ignore = ignore_protect_proc,
+ };
+ }
+
+ if (ns_info->private_ipc)
+ *(m++) = (MountEntry) {
+ .path_const = "/dev/mqueue",
+ .mode = MQUEUEFS,
+ .flags = MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_RELATIME,
+ };
+
+ 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 = NULL;
+
+ 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),
+ };
+ }
+
+ /* Will be used to add bind mounts at runtime */
+ if (setup_propagate)
+ *(m++) = (MountEntry) {
+ .source_const = propagate_dir,
+ .path_const = incoming_dir,
+ .mode = BIND_MOUNT,
+ .read_only = true,
+ };
+
+ if (notify_socket)
+ *(m++) = (MountEntry) {
+ .path_const = notify_socket,
+ .source_const = notify_socket,
+ .mode = BIND_MOUNT,
+ .read_only = true,
+ };
+
+ 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;
+
+ drop_unused_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;
+ }
+
+ /* Create the source directory to allow runtime propagation of mounts */
+ if (setup_propagate)
+ (void) mkdir_p(propagate_dir, 0600);
+
+ if (n_extension_images > 0 || !strv_isempty(extension_directories))
+ /* ExtensionImages/Directories mountpoint directories will be created while parsing the
+ * mounts to create, so have the parent ready */
+ (void) mkdir_p(extension_dir, 0600);
+
+ /* 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, UID_INVALID, dissect_image_flags);
+ if (r < 0) {
+ log_debug_errno(r, "Failed to mount root image: %m");
+ goto finish;
+ }
+
+ /* Now release the block device lock, so that udevd is free to call BLKRRPART on the device
+ * if it likes. */
+ r = loop_device_flock(loop_device, LOCK_UN);
+ if (r < 0) {
+ log_debug_errno(r, "Failed to release lock on loopback block device: %m");
+ goto finish;
+ }
+
+ r = dissected_image_relinquish(dissected_image);
+ if (r < 0) {
+ log_debug_errno(r, "Failed to relinquish dissected image: %m");
+ goto finish;
+ }
+
+ } 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);
+
+ /* Now make the magic happen */
+ r = apply_mounts(root, ns_info, mounts, &n_mounts, exec_dir_symlinks, error_path);
+ if (r < 0)
+ 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 == -EINVAL && root_directory) {
+ /* If we are using root_directory and we don't have privileges (ie: user manager in a user
+ * namespace) and the root_directory is already a mount point in the parent namespace,
+ * MS_MOVE will fail as we don't have permission to change it (with EINVAL rather than
+ * EPERM). Attempt to bind-mount it over itself (like we do above if it's not already a
+ * mount point) and try again. */
+ r = mount_nofollow_verbose(LOG_DEBUG, root, root, NULL, MS_BIND|MS_REC, NULL);
+ if (r < 0)
+ goto finish;
+ 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;
+ }
+
+ /* bind_mount_in_namespace() will MS_MOVE into that directory, and that's only
+ * supported for non-shared mounts. This needs to happen after remounting / or it will fail. */
+ if (setup_propagate) {
+ r = mount(NULL, incoming_dir, NULL, MS_SLAVE, NULL);
+ if (r < 0) {
+ log_error_errno(r, "Failed to remount %s with MS_SLAVE: %m", incoming_dir);
+ 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) {
+ assert(b || n == 0);
+
+ for (size_t 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) {
+ assert(n);
+ assert(m || *n == 0);
+
+ for (size_t 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;
+ MountImage *c;
+
+ assert(m);
+ assert(n);
+ assert(item);
+
+ s = strdup(item->source);
+ if (!s)
+ return -ENOMEM;
+
+ if (item->destination) {
+ d = strdup(item->destination);
+ if (!d)
+ return -ENOMEM;
+ }
+
+ LIST_FOREACH(mount_options, i, item->mount_options) {
+ _cleanup_(mount_options_free_allp) MountOptions *o = NULL;
+
+ 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,
+ .type = item->type,
+ };
+
+ return 0;
+}
+
+void temporary_filesystem_free_many(TemporaryFileSystem *t, size_t n) {
+ assert(t || n == 0);
+
+ for (size_t 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;
+ _cleanup_close_ int fd = -1;
+ 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;
+
+ RUN_WITH_UMASK(000)
+ r = mkdir_parents(prefix, 0755);
+ if (r < 0)
+ return r;
+
+ r = tempfn_random(prefix, NULL, &t);
+ if (r < 0)
+ return r;
+
+ /* umask will corrupt this access mode, but that doesn't matter, we need to call chmod() anyway for
+ * the suid bit, below. */
+ fd = open_mkdir_at(AT_FDCWD, t, O_EXCL|O_CLOEXEC, 0777);
+ if (fd < 0)
+ return fd;
+
+ r = RET_NERRNO(fchmod(fd, 01777));
+ if (r < 0) {
+ (void) rmdir(t);
+ return r;
+ }
+
+ r = RET_NERRNO(rename(t, prefix));
+ if (r < 0) {
+ (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;
+ 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), "-", 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_full(AT_FDCWD, 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. */
+ RUN_WITH_UMASK(0000)
+ 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_shareable_ns(const int ns_storage_socket[static 2], unsigned long nsflag) {
+ _cleanup_close_ int ns = -1;
+ int r, q;
+ const char *ns_name, *ns_path;
+
+ assert(ns_storage_socket);
+ assert(ns_storage_socket[0] >= 0);
+ assert(ns_storage_socket[1] >= 0);
+
+ ns_name = namespace_single_flag_to_string(nsflag);
+ assert(ns_name);
+
+ /* 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(ns_storage_socket[0], F_LOCK, 0) < 0)
+ return -errno;
+
+ ns = receive_one_fd(ns_storage_socket[0], MSG_DONTWAIT);
+ if (ns == -EAGAIN) {
+ /* Nothing stored yet, so let's create a new namespace. */
+
+ if (unshare(nsflag) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ (void) loopback_setup();
+
+ ns_path = strjoina("/proc/self/ns/", ns_name);
+ ns = open(ns_path, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+ if (ns < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ r = 1;
+
+ } else if (ns < 0) {
+ r = ns;
+ goto fail;
+
+ } else {
+ /* Yay, found something, so let's join the namespace */
+ if (setns(ns, nsflag) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ r = 0;
+ }
+
+ q = send_one_fd(ns_storage_socket[1], ns, MSG_DONTWAIT);
+ if (q < 0) {
+ r = q;
+ goto fail;
+ }
+
+fail:
+ (void) lockf(ns_storage_socket[0], F_ULOCK, 0);
+ return r;
+}
+
+int open_shareable_ns_path(const int ns_storage_socket[static 2], const char *path, unsigned long nsflag) {
+ _cleanup_close_ int ns = -1;
+ int q, r;
+
+ assert(ns_storage_socket);
+ assert(ns_storage_socket[0] >= 0);
+ assert(ns_storage_socket[1] >= 0);
+ assert(path);
+
+ /* If the storage socket doesn't contain a ns 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_shareable_ns() which will
+ * allocate a new anonymous ns if needed. */
+
+ if (lockf(ns_storage_socket[0], F_LOCK, 0) < 0)
+ return -errno;
+
+ ns = receive_one_fd(ns_storage_socket[0], MSG_DONTWAIT);
+ if (ns == -EAGAIN) {
+ /* Nothing stored yet. Open the file from the file system. */
+
+ ns = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+ if (ns < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ r = fd_is_ns(ns, nsflag);
+ if (r == 0) { /* Not a ns of our type? Refuse early. */
+ r = -EINVAL;
+ goto fail;
+ }
+ if (r < 0 && r != -EUCLEAN) /* EUCLEAN: we don't know */
+ goto fail;
+
+ r = 1;
+
+ } else if (ns < 0) {
+ r = ns;
+ goto fail;
+ } else
+ r = 0; /* Already allocated */
+
+ q = send_one_fd(ns_storage_socket[1], ns, MSG_DONTWAIT);
+ if (q < 0) {
+ r = q;
+ goto fail;
+ }
+
+fail:
+ (void) lockf(ns_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",
+ [NAMESPACE_TIME] = "time",
+};
+
+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);