mirror of
https://github.com/morgan9e/systemd
synced 2026-04-14 00:14:32 +09:00
63855693dc
Commit 88fce09 modified the mount_bind() function, causing it to perform
arithmetic on the uid_shift parameter. However, it performs this
arithmetic even when uid_shift was UID_INVALID, which was not intended.
This typically occurred when mount_custom() was called for a simple bind
mount without user namespaces (and thus no rootidmap mount option).
This arithmetic (e.g., uid_shift + m->destination_uid) then wraps
around, resulting in the invalid ID 4294967295 ((uid_t)-1).
This bug manifests for users running systemd-nspawn with
--link-journal=host and --volatile=yes (but without --private-users),
causing systemd-tmpfiles to fail.
Make mount_bind() robust by checking if uid_shift is valid before using
it in arithmetic. If it is UID_INVALID, it defaults to a shift of 0 for
the ownership calculation, restoring correct behavior for plain bind
mounts while preserving the intended logic for ID-mapped mounts.
Fixes: #39714
1522 lines
59 KiB
C
1522 lines
59 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <linux/magic.h>
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#include <sys/mount.h>
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#include <unistd.h>
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#include "alloc-util.h"
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#include "chase.h"
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#include "errno-util.h"
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#include "escape.h"
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#include "extract-word.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 "log.h"
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#include "mkdir-label.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 "nspawn-mount.h"
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#include "path-util.h"
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#include "rm-rf.h"
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#include "sort-util.h"
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#include "stat-util.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 "user-util.h"
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CustomMount* custom_mount_add(CustomMount **l, size_t *n, CustomMountType t) {
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CustomMount *ret;
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assert(l);
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assert(n);
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assert(t >= 0);
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assert(t < _CUSTOM_MOUNT_TYPE_MAX);
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if (!GREEDY_REALLOC(*l, *n + 1))
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return NULL;
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ret = *l + *n;
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(*n)++;
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*ret = (CustomMount) {
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.type = t,
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.destination_uid = UID_INVALID,
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};
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return ret;
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}
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void custom_mount_free_all(CustomMount *l, size_t n) {
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FOREACH_ARRAY(m, l, n) {
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free(m->source);
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free(m->destination);
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free(m->options);
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if (m->work_dir) {
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(void) rm_rf(m->work_dir, REMOVE_ROOT|REMOVE_PHYSICAL);
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free(m->work_dir);
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}
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if (m->rm_rf_tmpdir) {
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(void) rm_rf(m->rm_rf_tmpdir, REMOVE_ROOT|REMOVE_PHYSICAL);
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free(m->rm_rf_tmpdir);
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}
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strv_free(m->lower);
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free(m->type_argument);
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}
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free(l);
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}
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static int custom_mount_compare(const CustomMount *a, const CustomMount *b) {
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int r;
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r = path_compare(a->destination, b->destination);
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if (r != 0)
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return r;
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return CMP(a->type, b->type);
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}
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static int source_path_parse(const char *p, char **ret) {
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assert(p);
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assert(ret);
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if (isempty(p))
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return -EINVAL;
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if (*p == '+') {
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if (!path_is_absolute(p + 1))
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return -EINVAL;
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char *s = strdup(p);
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if (!s)
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return -ENOMEM;
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*ret = TAKE_PTR(s);
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return 0;
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}
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return path_make_absolute_cwd(p, ret);
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}
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static int source_path_parse_nullable(const char *p, char **ret) {
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assert(p);
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assert(ret);
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if (isempty(p)) {
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*ret = NULL;
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return 0;
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}
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return source_path_parse(p, ret);
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}
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static char *resolve_source_path(const char *dest, const char *source) {
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if (!source)
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return NULL;
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if (source[0] == '+')
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return path_join(dest, source + 1);
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return strdup(source);
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}
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static int allocate_temporary_source(CustomMount *m) {
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int r;
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assert(m);
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assert(!m->source);
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assert(!m->rm_rf_tmpdir);
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r = mkdtemp_malloc("/var/tmp/nspawn-temp-XXXXXX", &m->rm_rf_tmpdir);
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if (r < 0)
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return log_error_errno(r, "Failed to acquire temporary directory: %m");
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m->source = path_join(m->rm_rf_tmpdir, "src");
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if (!m->source)
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return log_oom();
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if (mkdir(m->source, 0755) < 0)
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return log_error_errno(errno, "Failed to create %s: %m", m->source);
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return 0;
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}
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int custom_mount_prepare_all(const char *dest, CustomMount *l, size_t n) {
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int r;
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/* Prepare all custom mounts. This will make sure we know all temporary directories. This is called in the
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* parent process, so that we know the temporary directories to remove on exit before we fork off the
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* children. */
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assert(l || n == 0);
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/* Order the custom mounts, and make sure we have a working directory */
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typesafe_qsort(l, n, custom_mount_compare);
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FOREACH_ARRAY(m, l, n) {
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/* /proc we mount in the inner child, i.e. when we acquired CLONE_NEWPID. All other mounts we mount
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* already in the outer child, so that the mounts are already established before CLONE_NEWPID and in
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* particular CLONE_NEWUSER. This also means any custom mounts below /proc also need to be mounted in
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* the inner child, not the outer one. Determine this here. */
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m->in_userns = path_startswith(m->destination, "/proc");
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if (m->type == CUSTOM_MOUNT_BIND) {
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if (m->source) {
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char *s;
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s = resolve_source_path(dest, m->source);
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if (!s)
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return log_oom();
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free_and_replace(m->source, s);
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} else {
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/* No source specified? In that case, use a throw-away temporary directory in /var/tmp */
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r = allocate_temporary_source(m);
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if (r < 0)
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return r;
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}
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}
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if (m->type == CUSTOM_MOUNT_OVERLAY) {
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STRV_FOREACH(j, m->lower) {
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char *s;
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s = resolve_source_path(dest, *j);
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if (!s)
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return log_oom();
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free_and_replace(*j, s);
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}
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if (m->source) {
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char *s;
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s = resolve_source_path(dest, m->source);
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if (!s)
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return log_oom();
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free_and_replace(m->source, s);
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} else {
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r = allocate_temporary_source(m);
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if (r < 0)
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return r;
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}
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if (m->work_dir) {
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char *s;
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s = resolve_source_path(dest, m->work_dir);
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if (!s)
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return log_oom();
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free_and_replace(m->work_dir, s);
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} else {
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r = tempfn_random(m->source, NULL, &m->work_dir);
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if (r < 0)
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return log_error_errno(r, "Failed to acquire working directory: %m");
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}
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(void) mkdir_label(m->work_dir, 0700);
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}
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}
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return 0;
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}
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int bind_mount_parse(CustomMount **l, size_t *n, const char *s, bool read_only) {
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_cleanup_free_ char *source = NULL, *destination = NULL, *opts = NULL, *p = NULL;
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CustomMount *m;
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int r;
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assert(l);
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assert(n);
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r = extract_many_words(&s, ":", EXTRACT_DONT_COALESCE_SEPARATORS, &source, &destination);
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if (r < 0)
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return r;
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if (r == 0)
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return -EINVAL;
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if (r == 1) {
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destination = strdup(source[0] == '+' ? source+1 : source);
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if (!destination)
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return -ENOMEM;
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}
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if (r == 2 && !isempty(s)) {
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opts = strdup(s);
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if (!opts)
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return -ENOMEM;
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}
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r = source_path_parse_nullable(source, &p);
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if (r < 0)
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return r;
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if (!path_is_absolute(destination))
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return -EINVAL;
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m = custom_mount_add(l, n, CUSTOM_MOUNT_BIND);
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if (!m)
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return -ENOMEM;
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m->source = TAKE_PTR(p);
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m->destination = TAKE_PTR(destination);
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m->read_only = read_only;
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m->options = TAKE_PTR(opts);
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return 0;
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}
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int tmpfs_mount_parse(CustomMount **l, size_t *n, const char *s) {
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_cleanup_free_ char *path = NULL, *opts = NULL;
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const char *p = ASSERT_PTR(s);
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CustomMount *m;
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int r;
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assert(l);
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assert(n);
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r = extract_first_word(&p, &path, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
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if (r < 0)
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return r;
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if (r == 0)
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return -EINVAL;
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if (isempty(p))
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opts = strdup("mode=0755");
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else
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opts = strdup(p);
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if (!opts)
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return -ENOMEM;
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if (!path_is_absolute(path))
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return -EINVAL;
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m = custom_mount_add(l, n, CUSTOM_MOUNT_TMPFS);
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if (!m)
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return -ENOMEM;
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m->destination = TAKE_PTR(path);
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m->options = TAKE_PTR(opts);
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return 0;
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}
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int overlay_mount_parse(CustomMount **l, size_t *n, const char *s, bool read_only) {
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_cleanup_free_ char *upper = NULL, *destination = NULL;
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_cleanup_strv_free_ char **lower = NULL;
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CustomMount *m;
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int r, k;
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k = strv_split_full(&lower, s, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
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if (k < 0)
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return k;
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if (k < 2)
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return -EADDRNOTAVAIL;
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if (k == 2) {
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_cleanup_free_ char *p = NULL;
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/* If two parameters are specified, the first one is the lower, the second one the upper directory. And
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* we'll also define the destination mount point the same as the upper. */
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r = source_path_parse(lower[0], &p);
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if (r < 0)
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return r;
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free_and_replace(lower[0], p);
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r = source_path_parse(lower[1], &p);
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if (r < 0)
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return r;
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free_and_replace(lower[1], p);
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upper = TAKE_PTR(lower[1]);
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destination = strdup(upper[0] == '+' ? upper+1 : upper); /* take the destination without "+" prefix */
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if (!destination)
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return -ENOMEM;
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} else {
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_cleanup_free_ char *p = NULL;
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/* If more than two parameters are specified, the last one is the destination, the second to last one
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* the "upper", and all before that the "lower" directories. */
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destination = lower[k - 1];
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upper = TAKE_PTR(lower[k - 2]);
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STRV_FOREACH(i, lower) {
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r = source_path_parse(*i, &p);
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if (r < 0)
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return r;
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free_and_replace(*i, p);
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}
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/* If the upper directory is unspecified, then let's create it automatically as a throw-away directory
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* in /var/tmp */
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r = source_path_parse_nullable(upper, &p);
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if (r < 0)
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return r;
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free_and_replace(upper, p);
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if (!path_is_absolute(destination))
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return -EINVAL;
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}
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m = custom_mount_add(l, n, CUSTOM_MOUNT_OVERLAY);
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if (!m)
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return -ENOMEM;
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m->destination = TAKE_PTR(destination);
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m->source = TAKE_PTR(upper);
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m->lower = TAKE_PTR(lower);
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m->read_only = read_only;
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return 0;
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}
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int inaccessible_mount_parse(CustomMount **l, size_t *n, const char *s) {
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_cleanup_free_ char *path = NULL;
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CustomMount *m;
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assert(l);
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assert(n);
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assert(s);
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if (!path_is_absolute(s))
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return -EINVAL;
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path = strdup(s);
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if (!path)
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return -ENOMEM;
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m = custom_mount_add(l, n, CUSTOM_MOUNT_INACCESSIBLE);
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if (!m)
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return -ENOMEM;
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m->destination = TAKE_PTR(path);
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return 0;
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}
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int tmpfs_patch_options(
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const char *options,
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uid_t uid_shift,
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const char *selinux_apifs_context,
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char **ret) {
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_cleanup_free_ char *buf = NULL;
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assert(ret);
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if (options) {
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buf = strdup(options);
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if (!buf)
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return -ENOMEM;
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}
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if (uid_shift != UID_INVALID)
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if (strextendf_with_separator(&buf, ",", "uid=" UID_FMT ",gid=" UID_FMT, uid_shift, uid_shift) < 0)
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return -ENOMEM;
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#if HAVE_SELINUX
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if (selinux_apifs_context)
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if (strextendf_with_separator(&buf, ",", "context=\"%s\"", selinux_apifs_context) < 0)
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return -ENOMEM;
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#endif
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*ret = TAKE_PTR(buf);
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return !!*ret;
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}
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int mount_sysfs(const char *dest, MountSettingsMask mount_settings) {
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_cleanup_free_ char *top = NULL, *full = NULL;;
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unsigned long extra_flags = 0;
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int r;
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top = path_join(dest, "/sys");
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if (!top)
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return log_oom();
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r = path_is_mount_point(top);
|
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if (r < 0)
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return log_error_errno(r, "Failed to determine if '%s' is a mountpoint: %m", top);
|
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if (r == 0) {
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/* If this is not a mount point yet, then mount a tmpfs there */
|
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r = mount_nofollow_verbose(LOG_ERR, "tmpfs", top, "tmpfs", MS_NOSUID|MS_NOEXEC|MS_NODEV, "mode=0555" TMPFS_LIMITS_SYS);
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if (r < 0)
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return r;
|
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} else {
|
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r = path_is_fs_type(top, SYSFS_MAGIC);
|
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if (r < 0)
|
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return log_error_errno(r, "Failed to determine filesystem type of %s: %m", top);
|
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|
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/* /sys/ might already be mounted as sysfs by the outer child in the !netns case. In this case, it's
|
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* all good. Don't touch it because we don't have the right to do so, see
|
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* https://github.com/systemd/systemd/issues/1555.
|
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*/
|
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if (r > 0)
|
||
return 0;
|
||
}
|
||
|
||
full = path_join(top, "/full");
|
||
if (!full)
|
||
return log_oom();
|
||
|
||
if (mkdir(full, 0755) < 0 && errno != EEXIST)
|
||
return log_error_errno(errno, "Failed to create directory '%s': %m", full);
|
||
|
||
if (FLAGS_SET(mount_settings, MOUNT_APPLY_APIVFS_RO))
|
||
extra_flags |= MS_RDONLY;
|
||
|
||
r = mount_nofollow_verbose(LOG_ERR, "sysfs", full, "sysfs",
|
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MS_NOSUID|MS_NOEXEC|MS_NODEV|extra_flags, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
FOREACH_STRING(x, "block", "bus", "class", "dev", "devices", "kernel") {
|
||
_cleanup_free_ char *from = NULL, *to = NULL;
|
||
|
||
from = path_join(full, x);
|
||
if (!from)
|
||
return log_oom();
|
||
|
||
to = path_join(top, x);
|
||
if (!to)
|
||
return log_oom();
|
||
|
||
(void) mkdir(to, 0755);
|
||
|
||
r = mount_nofollow_verbose(LOG_ERR, from, to, NULL, MS_BIND, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = mount_nofollow_verbose(LOG_ERR, NULL, to, NULL,
|
||
MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
r = umount_verbose(LOG_ERR, full, UMOUNT_NOFOLLOW);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
if (rmdir(full) < 0)
|
||
return log_error_errno(errno, "Failed to remove %s: %m", full);
|
||
|
||
/* Create mountpoints. Otherwise we are not allowed since we remount /sys/ read-only. */
|
||
FOREACH_STRING(p, "/fs/cgroup", "/fs/bpf") {
|
||
_cleanup_free_ char *x = path_join(top, p);
|
||
if (!x)
|
||
return log_oom();
|
||
|
||
(void) mkdir_p(x, 0755);
|
||
}
|
||
|
||
return mount_nofollow_verbose(LOG_ERR, NULL, top, NULL,
|
||
MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL);
|
||
}
|
||
|
||
#define PROC_DEFAULT_MOUNT_FLAGS (MS_NOSUID|MS_NOEXEC|MS_NODEV)
|
||
#define SYS_DEFAULT_MOUNT_FLAGS (MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV)
|
||
|
||
int mount_all(const char *dest,
|
||
MountSettingsMask mount_settings,
|
||
uid_t uid_shift,
|
||
const char *selinux_apifs_context) {
|
||
|
||
#define PROC_INACCESSIBLE_REG(path) \
|
||
{ "/run/systemd/inaccessible/reg", (path), NULL, NULL, MS_BIND, \
|
||
MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ \
|
||
{ NULL, (path), NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, \
|
||
MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO } /* Then, make it r/o */
|
||
|
||
#define PROC_READ_ONLY(path) \
|
||
{ (path), (path), NULL, NULL, MS_BIND, \
|
||
MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ \
|
||
{ NULL, (path), NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, \
|
||
MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO } /* Then, make it r/o */
|
||
|
||
typedef struct MountPoint {
|
||
const char *what;
|
||
const char *where;
|
||
const char *type;
|
||
const char *options;
|
||
unsigned long flags;
|
||
MountSettingsMask mount_settings;
|
||
} MountPoint;
|
||
|
||
static const MountPoint mount_table[] = {
|
||
/* First we list inner child mounts (i.e. mounts applied *after* entering user namespacing when we are privileged) */
|
||
{ "proc", "/proc", "proc", NULL, PROC_DEFAULT_MOUNT_FLAGS,
|
||
MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_MKDIR|MOUNT_FOLLOW_SYMLINKS }, /* we follow symlinks here since not following them requires /proc/ already being mounted, which we don't have here. */
|
||
|
||
{ "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND,
|
||
MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */
|
||
|
||
{ "/proc/sys/net", "/proc/sys/net", NULL, NULL, MS_BIND,
|
||
MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO|MOUNT_APPLY_APIVFS_NETNS }, /* (except for this) */
|
||
|
||
{ NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT,
|
||
MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* ... then, make it r/o */
|
||
|
||
/* Make these files inaccessible to container payloads: they potentially leak information about kernel
|
||
* internals or the host's execution environment to the container */
|
||
PROC_INACCESSIBLE_REG("/proc/kallsyms"),
|
||
PROC_INACCESSIBLE_REG("/proc/kcore"),
|
||
PROC_INACCESSIBLE_REG("/proc/keys"),
|
||
PROC_INACCESSIBLE_REG("/proc/sysrq-trigger"),
|
||
PROC_INACCESSIBLE_REG("/proc/timer_list"),
|
||
|
||
/* Make these directories read-only to container payloads: they show hardware information, and in some
|
||
* cases contain tunables the container really shouldn't have access to. */
|
||
PROC_READ_ONLY("/proc/acpi"),
|
||
PROC_READ_ONLY("/proc/apm"),
|
||
PROC_READ_ONLY("/proc/asound"),
|
||
PROC_READ_ONLY("/proc/bus"),
|
||
PROC_READ_ONLY("/proc/fs"),
|
||
PROC_READ_ONLY("/proc/irq"),
|
||
PROC_READ_ONLY("/proc/scsi"),
|
||
|
||
{ "mqueue", "/dev/mqueue", "mqueue", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
|
||
MOUNT_IN_USERNS|MOUNT_MKDIR },
|
||
|
||
/* Then we list outer child mounts (i.e. mounts applied *before* entering user namespacing when we are privileged) */
|
||
{ "tmpfs", "/tmp", "tmpfs", "mode=01777" NESTED_TMPFS_LIMITS, MS_NOSUID|MS_NODEV|MS_STRICTATIME,
|
||
MOUNT_FATAL|MOUNT_APPLY_TMPFS_TMP|MOUNT_MKDIR|MOUNT_USRQUOTA_GRACEFUL },
|
||
{ "tmpfs", "/sys", "tmpfs", "mode=0555" TMPFS_LIMITS_SYS, MS_NOSUID|MS_NOEXEC|MS_NODEV,
|
||
MOUNT_FATAL|MOUNT_APPLY_APIVFS_NETNS|MOUNT_MKDIR|MOUNT_UNMANAGED },
|
||
{ "sysfs", "/sys", "sysfs", NULL, SYS_DEFAULT_MOUNT_FLAGS,
|
||
MOUNT_FATAL|MOUNT_APPLY_APIVFS_RO|MOUNT_MKDIR|MOUNT_UNMANAGED }, /* skipped if above was mounted */
|
||
{ "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
|
||
MOUNT_FATAL|MOUNT_MKDIR|MOUNT_UNMANAGED }, /* skipped if above was mounted */
|
||
{ "tmpfs", "/dev", "tmpfs", "mode=0755" TMPFS_LIMITS_PRIVATE_DEV, MS_NOSUID|MS_STRICTATIME,
|
||
MOUNT_FATAL|MOUNT_MKDIR },
|
||
{ "tmpfs", "/dev/shm", "tmpfs", "mode=01777" NESTED_TMPFS_LIMITS, MS_NOSUID|MS_NODEV|MS_STRICTATIME,
|
||
MOUNT_FATAL|MOUNT_MKDIR|MOUNT_USRQUOTA_GRACEFUL },
|
||
{ "tmpfs", "/run", "tmpfs", "mode=0755" TMPFS_LIMITS_RUN, MS_NOSUID|MS_NODEV|MS_STRICTATIME,
|
||
MOUNT_FATAL|MOUNT_MKDIR },
|
||
{ "/run/host", "/run/host", NULL, NULL, MS_BIND,
|
||
MOUNT_FATAL|MOUNT_MKDIR|MOUNT_PREFIX_ROOT }, /* Prepare this so that we can make it read-only when we are done */
|
||
{ "/etc/os-release", "/run/host/os-release", NULL, NULL, MS_BIND,
|
||
MOUNT_TOUCH }, /* As per kernel interface requirements, bind mount first (creating mount points) and make read-only later */
|
||
{ "/usr/lib/os-release", "/run/host/os-release", NULL, NULL, MS_BIND,
|
||
MOUNT_FATAL }, /* If /etc/os-release doesn't exist use the version in /usr/lib as fallback */
|
||
{ NULL, "/run/host/os-release", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT,
|
||
MOUNT_FATAL },
|
||
{ NULL, "/run/host/os-release", NULL, NULL, MS_PRIVATE,
|
||
MOUNT_FATAL }, /* Turn off propagation (we only want that for the mount propagation tunnel dir) */
|
||
{ NULL, "/run/host", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT,
|
||
MOUNT_FATAL|MOUNT_IN_USERNS },
|
||
#if HAVE_SELINUX
|
||
{ "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND,
|
||
MOUNT_MKDIR|MOUNT_PRIVILEGED }, /* Bind mount first (mkdir/chown the mount point in case /sys/ is mounted as minimal skeleton tmpfs) */
|
||
{ NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT,
|
||
MOUNT_UNMANAGED|MOUNT_PRIVILEGED }, /* Then, make it r/o (don't mkdir/chown the mount point here, the previous entry already did that) */
|
||
{ NULL, "/sys/fs/selinux", NULL, NULL, MS_PRIVATE,
|
||
MOUNT_UNMANAGED|MOUNT_PRIVILEGED }, /* Turn off propagation (we only want that for the mount propagation tunnel dir) */
|
||
#endif
|
||
};
|
||
|
||
bool use_userns = FLAGS_SET(mount_settings, MOUNT_USE_USERNS);
|
||
bool netns = FLAGS_SET(mount_settings, MOUNT_APPLY_APIVFS_NETNS);
|
||
bool ro = FLAGS_SET(mount_settings, MOUNT_APPLY_APIVFS_RO);
|
||
bool in_userns = FLAGS_SET(mount_settings, MOUNT_IN_USERNS);
|
||
bool tmpfs_tmp = FLAGS_SET(mount_settings, MOUNT_APPLY_TMPFS_TMP);
|
||
bool unmanaged = FLAGS_SET(mount_settings, MOUNT_UNMANAGED);
|
||
bool privileged = FLAGS_SET(mount_settings, MOUNT_PRIVILEGED);
|
||
int r;
|
||
|
||
FOREACH_ELEMENT(m, mount_table) {
|
||
_cleanup_free_ char *where = NULL, *options = NULL, *prefixed = NULL;
|
||
bool fatal = FLAGS_SET(m->mount_settings, MOUNT_FATAL);
|
||
const char *o;
|
||
|
||
/* If we are in managed user namespace mode but the entry is marked for mount outside of
|
||
* managed user namespace mode, and to be mounted outside the user namespace, then skip it */
|
||
if (!unmanaged && FLAGS_SET(m->mount_settings, MOUNT_UNMANAGED) && !FLAGS_SET(m->mount_settings, MOUNT_IN_USERNS))
|
||
continue;
|
||
|
||
if (in_userns != FLAGS_SET(m->mount_settings, MOUNT_IN_USERNS))
|
||
continue;
|
||
|
||
if (!netns && FLAGS_SET(m->mount_settings, MOUNT_APPLY_APIVFS_NETNS))
|
||
continue;
|
||
|
||
if (!ro && FLAGS_SET(m->mount_settings, MOUNT_APPLY_APIVFS_RO))
|
||
continue;
|
||
|
||
if (!tmpfs_tmp && FLAGS_SET(m->mount_settings, MOUNT_APPLY_TMPFS_TMP))
|
||
continue;
|
||
|
||
if (!privileged && FLAGS_SET(m->mount_settings, MOUNT_PRIVILEGED))
|
||
continue;
|
||
|
||
r = chase(m->where, dest, CHASE_NONEXISTENT|CHASE_PREFIX_ROOT, &where, NULL);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to resolve %s%s: %m", strempty(dest), m->where);
|
||
|
||
/* Skip this entry if it is not a remount. */
|
||
if (m->what) {
|
||
r = path_is_mount_point(where);
|
||
if (r < 0 && r != -ENOENT)
|
||
return log_error_errno(r, "Failed to detect whether %s is a mount point: %m", where);
|
||
if (r > 0)
|
||
continue;
|
||
}
|
||
|
||
if ((m->mount_settings & (MOUNT_MKDIR|MOUNT_TOUCH)) != 0) {
|
||
uid_t u = (use_userns && !in_userns) ? uid_shift : UID_INVALID;
|
||
|
||
if (FLAGS_SET(m->mount_settings, MOUNT_TOUCH))
|
||
r = mkdir_parents_safe(dest, where, 0755, u, u, 0);
|
||
else
|
||
r = mkdir_p_safe(dest, where, 0755, u, u, 0);
|
||
if (r < 0 && r != -EEXIST) {
|
||
if (fatal && r != -EROFS)
|
||
return log_error_errno(r, "Failed to create directory %s: %m", where);
|
||
|
||
log_debug_errno(r, "Failed to create directory %s: %m", where);
|
||
|
||
/* If mkdir() or chown() failed due to the root directory being read only,
|
||
* attempt to mount this fs anyway and let mount_verbose log any errors */
|
||
if (r != -EROFS)
|
||
continue;
|
||
}
|
||
}
|
||
|
||
if (FLAGS_SET(m->mount_settings, MOUNT_TOUCH)) {
|
||
r = touch(where);
|
||
if (r < 0 && r != -EEXIST) {
|
||
if (fatal && r != -EROFS)
|
||
return log_error_errno(r, "Failed to create file %s: %m", where);
|
||
|
||
log_debug_errno(r, "Failed to create file %s: %m", where);
|
||
if (r != -EROFS)
|
||
continue;
|
||
}
|
||
}
|
||
|
||
o = m->options;
|
||
if (streq_ptr(m->type, "tmpfs")) {
|
||
r = tmpfs_patch_options(o, in_userns ? 0 : uid_shift, selinux_apifs_context, &options);
|
||
if (r < 0)
|
||
return log_oom();
|
||
if (r > 0)
|
||
o = options;
|
||
}
|
||
|
||
if (FLAGS_SET(m->mount_settings, MOUNT_USRQUOTA_GRACEFUL)) {
|
||
r = mount_option_supported(m->type, /* key= */ "usrquota", /* value= */ NULL);
|
||
if (r < 0)
|
||
log_warning_errno(r, "Failed to determine if '%s' supports 'usrquota', assuming it doesn't: %m", m->type);
|
||
else if (r == 0)
|
||
log_debug("Kernel doesn't support 'usrquota' on '%s', not including in mount options for '%s'.", m->type, m->where);
|
||
else {
|
||
_cleanup_free_ char *joined = NULL;
|
||
|
||
if (!strextend_with_separator(&joined, ",", o ?: POINTER_MAX, "usrquota"))
|
||
return log_oom();
|
||
|
||
free_and_replace(options, joined);
|
||
o = options;
|
||
}
|
||
}
|
||
|
||
if (FLAGS_SET(m->mount_settings, MOUNT_PREFIX_ROOT)) {
|
||
/* Optionally prefix the mount source with the root dir. This is useful in bind
|
||
* mounts to be created within the container image before we transition into it. Note
|
||
* that MOUNT_IN_USERNS is run after we transitioned hence prefixing is not necessary
|
||
* for those. */
|
||
r = chase(m->what, dest, CHASE_PREFIX_ROOT, &prefixed, NULL);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to resolve %s%s: %m", strempty(dest), m->what);
|
||
}
|
||
|
||
r = mount_verbose_full(
|
||
fatal ? LOG_ERR : LOG_DEBUG,
|
||
prefixed ?: m->what,
|
||
where,
|
||
m->type,
|
||
m->flags,
|
||
o,
|
||
FLAGS_SET(m->mount_settings, MOUNT_FOLLOW_SYMLINKS));
|
||
if (r < 0 && fatal)
|
||
return r;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int parse_mount_bind_options(const char *options, unsigned long *open_tree_flags, char **mount_opts, RemountIdmapping *idmapping) {
|
||
unsigned long flags = *open_tree_flags;
|
||
char *opts = NULL;
|
||
RemountIdmapping new_idmapping = *idmapping;
|
||
int r;
|
||
|
||
assert(options);
|
||
|
||
for (;;) {
|
||
_cleanup_free_ char *word = NULL;
|
||
|
||
r = extract_first_word(&options, &word, ",", 0);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to extract mount option: %m");
|
||
if (r == 0)
|
||
break;
|
||
|
||
if (streq(word, "rbind"))
|
||
flags |= AT_RECURSIVE;
|
||
else if (streq(word, "norbind"))
|
||
flags &= ~AT_RECURSIVE;
|
||
else if (streq(word, "idmap"))
|
||
new_idmapping = REMOUNT_IDMAPPING_HOST_ROOT;
|
||
else if (streq(word, "noidmap"))
|
||
new_idmapping = REMOUNT_IDMAPPING_NONE;
|
||
else if (streq(word, "rootidmap"))
|
||
new_idmapping = REMOUNT_IDMAPPING_HOST_OWNER;
|
||
else if (streq(word, "owneridmap"))
|
||
new_idmapping = REMOUNT_IDMAPPING_HOST_OWNER_TO_TARGET_OWNER;
|
||
else
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
|
||
"Invalid bind mount option: %s", word);
|
||
}
|
||
|
||
*open_tree_flags = flags;
|
||
*idmapping = new_idmapping;
|
||
/* in the future mount_opts will hold string options for mount(2) */
|
||
*mount_opts = opts;
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int mount_bind(const char *dest, CustomMount *m, uid_t uid_shift, uid_t uid_range) {
|
||
_cleanup_free_ char *mount_opts = NULL, *where = NULL;
|
||
unsigned long open_tree_flags = OPEN_TREE_CLONE | OPEN_TREE_CLOEXEC | AT_RECURSIVE;
|
||
struct stat source_st, dest_st;
|
||
uid_t dest_uid = UID_INVALID;
|
||
int r;
|
||
RemountIdmapping idmapping = REMOUNT_IDMAPPING_NONE;
|
||
|
||
assert(dest);
|
||
assert(m);
|
||
|
||
if (m->options) {
|
||
r = parse_mount_bind_options(m->options, &open_tree_flags, &mount_opts, &idmapping);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
/* ID remapping cannot be done if user namespaces are not in use (uid_shift is UID_INVALID).
|
||
* Fail if idmapping was explicitly requested in this state. Otherwise, treat UID_INVALID
|
||
* as 0 for ownership operations. */
|
||
if (idmapping != REMOUNT_IDMAPPING_NONE && !uid_is_valid(uid_shift))
|
||
return log_error_errno(
|
||
SYNTHETIC_ERRNO(EINVAL),
|
||
"ID remapping requested for %s, but user namespacing is not enabled.",
|
||
m->source);
|
||
|
||
uid_t chown_uid = uid_is_valid(uid_shift) ? uid_shift : 0;
|
||
|
||
/* If this is a bind mount from a temporary sources change ownership of the source to the container's
|
||
* root UID. Otherwise it would always show up as "nobody" if user namespacing is used. */
|
||
if (m->rm_rf_tmpdir && chown(m->source, chown_uid, chown_uid) < 0)
|
||
return log_error_errno(errno, "Failed to chown %s: %m", m->source);
|
||
|
||
/* UID/GIDs of idmapped mounts are always resolved in the caller's user namespace. In other
|
||
* words, they're not nested. If we're doing an idmapped mount from a bind mount that's
|
||
* already idmapped itself, the old idmap is replaced with the new one. This means that the
|
||
* source uid which we put in the idmap userns has to be the uid of mount source in the
|
||
* caller's userns *without* any mount idmapping in place. To get that uid, we clone the
|
||
* mount source tree and clear any existing idmapping and temporarily mount that tree over
|
||
* the mount source before we stat the mount source to figure out the source uid. */
|
||
_cleanup_close_ int fd_clone =
|
||
idmapping == REMOUNT_IDMAPPING_NONE ?
|
||
RET_NERRNO(open_tree(
|
||
AT_FDCWD,
|
||
m->source,
|
||
open_tree_flags)) :
|
||
open_tree_try_drop_idmap(
|
||
AT_FDCWD,
|
||
m->source,
|
||
open_tree_flags);
|
||
if (fd_clone < 0)
|
||
return log_error_errno(errno, "Failed to clone %s: %m", m->source);
|
||
|
||
if (fstat(fd_clone, &source_st) < 0)
|
||
return log_error_errno(errno, "Failed to stat %s: %m", m->source);
|
||
|
||
r = chase(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination);
|
||
if (r > 0) { /* Path exists already? */
|
||
|
||
if (stat(where, &dest_st) < 0)
|
||
return log_error_errno(errno, "Failed to stat %s: %m", where);
|
||
|
||
dest_uid = uid_is_valid(m->destination_uid) ? chown_uid + m->destination_uid : dest_st.st_uid;
|
||
|
||
if (S_ISDIR(source_st.st_mode) && !S_ISDIR(dest_st.st_mode))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
|
||
"Cannot bind mount directory %s on file %s.",
|
||
m->source, where);
|
||
|
||
if (!S_ISDIR(source_st.st_mode) && S_ISDIR(dest_st.st_mode))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
|
||
"Cannot bind mount file %s on directory %s.",
|
||
m->source, where);
|
||
|
||
} else { /* Path doesn't exist yet? */
|
||
r = mkdir_parents_safe_label(dest, where, 0755, chown_uid, chown_uid, MKDIR_IGNORE_EXISTING);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to make parents of %s: %m", where);
|
||
|
||
/* Create the mount point. Any non-directory file can be
|
||
* mounted on any non-directory file (regular, fifo, socket,
|
||
* char, block).
|
||
*/
|
||
if (S_ISDIR(source_st.st_mode))
|
||
r = mkdir_label(where, 0755);
|
||
else
|
||
r = touch(where);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to create mount point %s: %m", where);
|
||
|
||
if (chown(where, chown_uid, chown_uid) < 0)
|
||
return log_error_errno(errno, "Failed to chown %s: %m", where);
|
||
|
||
dest_uid = chown_uid + (uid_is_valid(m->destination_uid) ? m->destination_uid : 0);
|
||
}
|
||
|
||
if (move_mount(fd_clone, "", AT_FDCWD, where, MOVE_MOUNT_F_EMPTY_PATH) < 0)
|
||
return log_error_errno(errno, "Failed to mount %s to %s: %m", m->source, where);
|
||
|
||
fd_clone = safe_close(fd_clone);
|
||
|
||
if (m->read_only) {
|
||
r = bind_remount_recursive(where, MS_RDONLY, MS_RDONLY, NULL);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Read-only bind mount failed: %m");
|
||
}
|
||
|
||
if (idmapping != REMOUNT_IDMAPPING_NONE) {
|
||
r = remount_idmap(STRV_MAKE(where), uid_shift, uid_range, source_st.st_uid, dest_uid, idmapping);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to map ids for bind mount %s: %m", where);
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int mount_tmpfs(const char *dest, CustomMount *m, uid_t uid_shift, const char *selinux_apifs_context) {
|
||
const char *options;
|
||
_cleanup_free_ char *buf = NULL, *where = NULL;
|
||
int r;
|
||
|
||
assert(dest);
|
||
assert(m);
|
||
|
||
r = chase(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination);
|
||
if (r == 0) { /* Doesn't exist yet? */
|
||
r = mkdir_p_label(where, 0755);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Creating mount point for tmpfs %s failed: %m", where);
|
||
}
|
||
|
||
r = tmpfs_patch_options(m->options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf);
|
||
if (r < 0)
|
||
return log_oom();
|
||
options = r > 0 ? buf : m->options;
|
||
|
||
return mount_nofollow_verbose(LOG_ERR, "tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, options);
|
||
}
|
||
|
||
static char *joined_and_escaped_lower_dirs(char **lower) {
|
||
_cleanup_strv_free_ char **sv = NULL;
|
||
|
||
sv = strv_copy(lower);
|
||
if (!sv)
|
||
return NULL;
|
||
|
||
strv_reverse(sv);
|
||
|
||
if (!strv_shell_escape(sv, ",:"))
|
||
return NULL;
|
||
|
||
return strv_join(sv, ":");
|
||
}
|
||
|
||
static int mount_overlay(const char *dest, CustomMount *m) {
|
||
_cleanup_free_ char *lower = NULL, *where = NULL, *escaped_source = NULL;
|
||
const char *options;
|
||
int r;
|
||
|
||
assert(dest);
|
||
assert(m);
|
||
|
||
r = chase(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination);
|
||
if (r == 0) { /* Doesn't exist yet? */
|
||
r = mkdir_label(where, 0755);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Creating mount point for overlay %s failed: %m", where);
|
||
}
|
||
|
||
(void) mkdir_p_label(m->source, 0755);
|
||
|
||
lower = joined_and_escaped_lower_dirs(m->lower);
|
||
if (!lower)
|
||
return log_oom();
|
||
|
||
escaped_source = shell_escape(m->source, ",:");
|
||
if (!escaped_source)
|
||
return log_oom();
|
||
|
||
if (m->read_only)
|
||
options = strjoina("lowerdir=", escaped_source, ":", lower);
|
||
else {
|
||
_cleanup_free_ char *escaped_work_dir = NULL;
|
||
|
||
escaped_work_dir = shell_escape(m->work_dir, ",:");
|
||
if (!escaped_work_dir)
|
||
return log_oom();
|
||
|
||
options = strjoina("lowerdir=", lower, ",upperdir=", escaped_source, ",workdir=", escaped_work_dir);
|
||
}
|
||
|
||
return mount_nofollow_verbose(LOG_ERR, "overlay", where, "overlay", m->read_only ? MS_RDONLY : 0, options);
|
||
}
|
||
|
||
static int mount_inaccessible(const char *dest, CustomMount *m) {
|
||
_cleanup_free_ char *where = NULL, *source = NULL;
|
||
struct stat st;
|
||
int r;
|
||
|
||
assert(dest);
|
||
assert(m);
|
||
|
||
r = chase_and_stat(m->destination, dest, CHASE_PREFIX_ROOT, &where, &st);
|
||
if (r < 0) {
|
||
log_full_errno(m->graceful ? LOG_DEBUG : LOG_ERR, r, "Failed to resolve %s/%s: %m", dest, m->destination);
|
||
return m->graceful ? 0 : r;
|
||
}
|
||
|
||
r = mode_to_inaccessible_node(NULL, st.st_mode, &source);
|
||
if (r < 0)
|
||
return m->graceful ? 0 : r;
|
||
|
||
r = mount_nofollow_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, source, where, NULL, MS_BIND, NULL);
|
||
if (r < 0)
|
||
return m->graceful ? 0 : r;
|
||
|
||
r = mount_nofollow_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, NULL, where, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL);
|
||
if (r < 0) {
|
||
(void) umount_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, where, UMOUNT_NOFOLLOW);
|
||
return m->graceful ? 0 : r;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int mount_arbitrary(const char *dest, CustomMount *m) {
|
||
_cleanup_free_ char *where = NULL;
|
||
int r;
|
||
|
||
assert(dest);
|
||
assert(m);
|
||
|
||
r = chase(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination);
|
||
if (r == 0) { /* Doesn't exist yet? */
|
||
r = mkdir_p_label(where, 0755);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Creating mount point for mount %s failed: %m", where);
|
||
}
|
||
|
||
return mount_nofollow_verbose(LOG_ERR, m->source, where, m->type_argument, 0, m->options);
|
||
}
|
||
|
||
int mount_custom(
|
||
const char *dest,
|
||
CustomMount *mounts, size_t n,
|
||
uid_t uid_shift,
|
||
uid_t uid_range,
|
||
const char *selinux_apifs_context,
|
||
MountSettingsMask mount_settings) {
|
||
int r;
|
||
|
||
assert(dest);
|
||
|
||
FOREACH_ARRAY(m, mounts, n) {
|
||
if (FLAGS_SET(mount_settings, MOUNT_IN_USERNS) != m->in_userns)
|
||
continue;
|
||
|
||
if (FLAGS_SET(mount_settings, MOUNT_ROOT_ONLY) && !path_equal(m->destination, "/"))
|
||
continue;
|
||
|
||
if (FLAGS_SET(mount_settings, MOUNT_NON_ROOT_ONLY) && path_equal(m->destination, "/"))
|
||
continue;
|
||
|
||
switch (m->type) {
|
||
|
||
case CUSTOM_MOUNT_BIND:
|
||
r = mount_bind(dest, m, uid_shift, uid_range);
|
||
break;
|
||
|
||
case CUSTOM_MOUNT_TMPFS:
|
||
r = mount_tmpfs(dest, m, uid_shift, selinux_apifs_context);
|
||
break;
|
||
|
||
case CUSTOM_MOUNT_OVERLAY:
|
||
r = mount_overlay(dest, m);
|
||
break;
|
||
|
||
case CUSTOM_MOUNT_INACCESSIBLE:
|
||
r = mount_inaccessible(dest, m);
|
||
break;
|
||
|
||
case CUSTOM_MOUNT_ARBITRARY:
|
||
r = mount_arbitrary(dest, m);
|
||
break;
|
||
|
||
default:
|
||
assert_not_reached();
|
||
}
|
||
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
bool has_custom_root_mount(const CustomMount *mounts, size_t n) {
|
||
FOREACH_ARRAY(m, mounts, n)
|
||
if (path_equal(m->destination, "/"))
|
||
return true;
|
||
|
||
return false;
|
||
}
|
||
|
||
static int setup_volatile_state(const char *directory) {
|
||
int r;
|
||
|
||
assert(directory);
|
||
|
||
/* --volatile=state means we simply overmount /var with a tmpfs, and the rest read-only. */
|
||
|
||
/* First, remount the root directory. */
|
||
r = bind_remount_recursive(directory, MS_RDONLY, MS_RDONLY, NULL);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to remount %s read-only: %m", directory);
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int setup_volatile_state_after_remount_idmap(const char *directory, uid_t uid_shift, const char *selinux_apifs_context) {
|
||
_cleanup_free_ char *buf = NULL;
|
||
int r;
|
||
|
||
assert(directory);
|
||
|
||
/* Then, after remount_idmap(), overmount /var/ with a tmpfs. */
|
||
|
||
_cleanup_free_ char *p = path_join(directory, "/var");
|
||
if (!p)
|
||
return log_oom();
|
||
|
||
r = mkdir(p, 0755);
|
||
if (r < 0 && errno != EEXIST)
|
||
return log_error_errno(errno, "Failed to create %s: %m", directory);
|
||
|
||
const char *options = "mode=0755" TMPFS_LIMITS_VOLATILE_STATE;
|
||
r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf);
|
||
if (r < 0)
|
||
return log_oom();
|
||
if (r > 0)
|
||
options = buf;
|
||
|
||
return mount_nofollow_verbose(LOG_ERR, "tmpfs", p, "tmpfs", MS_STRICTATIME, options);
|
||
}
|
||
|
||
static int setup_volatile_yes(const char *directory, uid_t uid_shift, const char *selinux_apifs_context) {
|
||
bool tmpfs_mounted = false, bind_mounted = false;
|
||
_cleanup_(rmdir_and_freep) char *template = NULL;
|
||
_cleanup_free_ char *buf = NULL, *bindir = NULL, *f = NULL, *t = NULL;
|
||
struct stat st;
|
||
int r;
|
||
|
||
assert(directory);
|
||
|
||
/* --volatile=yes means we mount a tmpfs to the root dir, and the original /usr to use inside it, and
|
||
* that read-only. Before we start setting this up let's validate if the image has the /usr merge
|
||
* implemented, and let's output a friendly log message if it hasn't. */
|
||
|
||
bindir = path_join(directory, "/bin");
|
||
if (!bindir)
|
||
return log_oom();
|
||
if (lstat(bindir, &st) < 0) {
|
||
if (errno != ENOENT)
|
||
return log_error_errno(errno, "Failed to stat /bin directory below image: %m");
|
||
|
||
/* ENOENT is fine, just means the image is probably just a naked /usr and we can create the
|
||
* rest. */
|
||
} else if (S_ISDIR(st.st_mode))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EISDIR),
|
||
"Sorry, --volatile=yes mode is not supported with OS images that have not merged /bin/, /sbin/, /lib/, /lib64/ into /usr/. "
|
||
"Please work with your distribution and help them adopt the merged /usr scheme.");
|
||
else if (!S_ISLNK(st.st_mode))
|
||
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
|
||
"Error starting image: if --volatile=yes is used /bin must be a symlink (for merged /usr support) or non-existent (in which case a symlink is created automatically).");
|
||
|
||
r = mkdtemp_malloc("/tmp/nspawn-volatile-XXXXXX", &template);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to create temporary directory: %m");
|
||
|
||
const char *options = "mode=0755" TMPFS_LIMITS_ROOTFS;
|
||
r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf);
|
||
if (r < 0)
|
||
goto fail;
|
||
if (r > 0)
|
||
options = buf;
|
||
|
||
r = mount_nofollow_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
tmpfs_mounted = true;
|
||
|
||
f = path_join(directory, "/usr");
|
||
if (!f) {
|
||
r = log_oom();
|
||
goto fail;
|
||
}
|
||
|
||
t = path_join(template, "/usr");
|
||
if (!t) {
|
||
r = log_oom();
|
||
goto fail;
|
||
}
|
||
|
||
r = mkdir(t, 0755);
|
||
if (r < 0 && errno != EEXIST) {
|
||
r = log_error_errno(errno, "Failed to create %s: %m", t);
|
||
goto fail;
|
||
}
|
||
|
||
r = mount_nofollow_verbose(LOG_ERR, f, t, NULL, MS_BIND|MS_REC, NULL);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
bind_mounted = true;
|
||
|
||
r = bind_remount_recursive(t, MS_RDONLY, MS_RDONLY, NULL);
|
||
if (r < 0) {
|
||
log_error_errno(r, "Failed to remount %s read-only: %m", t);
|
||
goto fail;
|
||
}
|
||
|
||
r = mount_nofollow_verbose(LOG_ERR, template, directory, NULL, MS_MOVE, NULL);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
(void) rmdir(template);
|
||
|
||
return 0;
|
||
|
||
fail:
|
||
if (bind_mounted)
|
||
(void) umount_verbose(LOG_ERR, t, UMOUNT_NOFOLLOW);
|
||
|
||
if (tmpfs_mounted)
|
||
(void) umount_verbose(LOG_ERR, template, UMOUNT_NOFOLLOW);
|
||
|
||
return r;
|
||
}
|
||
|
||
static int setup_volatile_overlay(const char *directory, uid_t uid_shift, const char *selinux_apifs_context) {
|
||
_cleanup_free_ char *buf = NULL, *escaped_directory = NULL, *escaped_upper = NULL, *escaped_work = NULL;
|
||
_cleanup_(rmdir_and_freep) char *template = NULL;
|
||
const char *upper, *work, *options;
|
||
bool tmpfs_mounted = false;
|
||
int r;
|
||
|
||
assert(directory);
|
||
|
||
/* --volatile=overlay means we mount an overlayfs to the root dir. */
|
||
|
||
r = mkdtemp_malloc("/tmp/nspawn-volatile-XXXXXX", &template);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to create temporary directory: %m");
|
||
|
||
options = "mode=0755" TMPFS_LIMITS_ROOTFS;
|
||
r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf);
|
||
if (r < 0)
|
||
goto finish;
|
||
if (r > 0)
|
||
options = buf;
|
||
|
||
r = mount_nofollow_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options);
|
||
if (r < 0)
|
||
goto finish;
|
||
|
||
tmpfs_mounted = true;
|
||
|
||
upper = strjoina(template, "/upper");
|
||
work = strjoina(template, "/work");
|
||
|
||
if (mkdir(upper, 0755) < 0) {
|
||
r = log_error_errno(errno, "Failed to create %s: %m", upper);
|
||
goto finish;
|
||
}
|
||
if (mkdir(work, 0755) < 0) {
|
||
r = log_error_errno(errno, "Failed to create %s: %m", work);
|
||
goto finish;
|
||
}
|
||
|
||
/* And now, let's overmount the root dir with an overlayfs that uses the root dir as lower dir. It's kinda nice
|
||
* that the kernel allows us to do that without going through some mount point rearrangements. */
|
||
|
||
escaped_directory = shell_escape(directory, ",:");
|
||
escaped_upper = shell_escape(upper, ",:");
|
||
escaped_work = shell_escape(work, ",:");
|
||
if (!escaped_directory || !escaped_upper || !escaped_work) {
|
||
r = -ENOMEM;
|
||
goto finish;
|
||
}
|
||
|
||
options = strjoina("lowerdir=", escaped_directory, ",upperdir=", escaped_upper, ",workdir=", escaped_work);
|
||
r = mount_nofollow_verbose(LOG_ERR, "overlay", directory, "overlay", 0, options);
|
||
|
||
finish:
|
||
if (tmpfs_mounted)
|
||
(void) umount_verbose(LOG_ERR, template, UMOUNT_NOFOLLOW);
|
||
|
||
return r;
|
||
}
|
||
|
||
int setup_volatile_mode(
|
||
const char *directory,
|
||
VolatileMode mode,
|
||
uid_t uid_shift,
|
||
const char *selinux_apifs_context) {
|
||
|
||
switch (mode) {
|
||
|
||
case VOLATILE_YES:
|
||
return setup_volatile_yes(directory, uid_shift, selinux_apifs_context);
|
||
|
||
case VOLATILE_STATE:
|
||
return setup_volatile_state(directory);
|
||
|
||
case VOLATILE_OVERLAY:
|
||
return setup_volatile_overlay(directory, uid_shift, selinux_apifs_context);
|
||
|
||
default:
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
int setup_volatile_mode_after_remount_idmap(
|
||
const char *directory,
|
||
VolatileMode mode,
|
||
uid_t uid_shift,
|
||
const char *selinux_apifs_context) {
|
||
|
||
switch (mode) {
|
||
|
||
case VOLATILE_STATE:
|
||
return setup_volatile_state_after_remount_idmap(directory, uid_shift, selinux_apifs_context);
|
||
|
||
default:
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
/* Expects *pivot_root_new and *pivot_root_old to be initialised to allocated memory or NULL. */
|
||
int pivot_root_parse(char **pivot_root_new, char **pivot_root_old, const char *s) {
|
||
_cleanup_free_ char *root_new = NULL, *root_old = NULL;
|
||
const char *p = s;
|
||
int r;
|
||
|
||
assert(pivot_root_new);
|
||
assert(pivot_root_old);
|
||
|
||
r = extract_first_word(&p, &root_new, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
|
||
if (r < 0)
|
||
return r;
|
||
if (r == 0)
|
||
return -EINVAL;
|
||
|
||
if (isempty(p))
|
||
root_old = NULL;
|
||
else {
|
||
root_old = strdup(p);
|
||
if (!root_old)
|
||
return -ENOMEM;
|
||
}
|
||
|
||
if (!path_is_absolute(root_new))
|
||
return -EINVAL;
|
||
if (root_old && !path_is_absolute(root_old))
|
||
return -EINVAL;
|
||
|
||
free_and_replace(*pivot_root_new, root_new);
|
||
free_and_replace(*pivot_root_old, root_old);
|
||
|
||
return 0;
|
||
}
|
||
|
||
int setup_pivot_root(const char *directory, const char *pivot_root_new, const char *pivot_root_old) {
|
||
_cleanup_free_ char *directory_pivot_root_new = NULL;
|
||
_cleanup_free_ char *pivot_tmp_pivot_root_old = NULL;
|
||
_cleanup_(rmdir_and_freep) char *pivot_tmp = NULL;
|
||
int r;
|
||
|
||
assert(directory);
|
||
|
||
if (!pivot_root_new)
|
||
return 0;
|
||
|
||
/* Pivot pivot_root_new to / and the existing / to pivot_root_old.
|
||
* If pivot_root_old is NULL, the existing / disappears.
|
||
* This requires a temporary directory, pivot_tmp, which is
|
||
* not a child of either.
|
||
*
|
||
* This is typically used for OSTree-style containers, where the root partition contains several
|
||
* sysroots which could be run. Normally, one would be chosen by the bootloader and pivoted to / by
|
||
* initrd.
|
||
*
|
||
* For example, for an OSTree deployment, pivot_root_new
|
||
* would be: /ostree/deploy/$os/deploy/$checksum. Note that this
|
||
* code doesn’t do the /var mount which OSTree expects: use
|
||
* --bind +/sysroot/ostree/deploy/$os/var:/var for that.
|
||
*
|
||
* So in the OSTree case, we’ll end up with something like:
|
||
* - directory = /tmp/nspawn-root-123456
|
||
* - pivot_root_new = /ostree/deploy/os/deploy/123abc
|
||
* - pivot_root_old = /sysroot
|
||
* - directory_pivot_root_new =
|
||
* /tmp/nspawn-root-123456/ostree/deploy/os/deploy/123abc
|
||
* - pivot_tmp = /tmp/nspawn-pivot-123456
|
||
* - pivot_tmp_pivot_root_old = /tmp/nspawn-pivot-123456/sysroot
|
||
*
|
||
* Requires all file systems at directory and below to be mounted
|
||
* MS_PRIVATE or MS_SLAVE so they can be moved.
|
||
*/
|
||
directory_pivot_root_new = path_join(directory, pivot_root_new);
|
||
if (!directory_pivot_root_new)
|
||
return log_oom();
|
||
|
||
/* Remount directory_pivot_root_new to make it movable. */
|
||
r = mount_nofollow_verbose(LOG_ERR, directory_pivot_root_new, directory_pivot_root_new, NULL, MS_BIND, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
if (pivot_root_old) {
|
||
r = mkdtemp_malloc("/tmp/nspawn-pivot-XXXXXX", &pivot_tmp);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to create temporary directory: %m");
|
||
|
||
pivot_tmp_pivot_root_old = path_join(pivot_tmp, pivot_root_old);
|
||
if (!pivot_tmp_pivot_root_old)
|
||
return log_oom();
|
||
|
||
r = mount_nofollow_verbose(LOG_ERR, directory_pivot_root_new, pivot_tmp, NULL, MS_MOVE, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = mount_nofollow_verbose(LOG_ERR, directory, pivot_tmp_pivot_root_old, NULL, MS_MOVE, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = mount_nofollow_verbose(LOG_ERR, pivot_tmp, directory, NULL, MS_MOVE, NULL);
|
||
} else
|
||
r = mount_nofollow_verbose(LOG_ERR, directory_pivot_root_new, directory, NULL, MS_MOVE, NULL);
|
||
|
||
if (r < 0)
|
||
return r;
|
||
|
||
return 0;
|
||
}
|
||
|
||
#define NSPAWN_PRIVATE_FULLY_VISIBLE_PROCFS "/run/host/proc"
|
||
#define NSPAWN_PRIVATE_FULLY_VISIBLE_SYSFS "/run/host/sys"
|
||
|
||
int pin_fully_visible_api_fs(void) {
|
||
int r;
|
||
|
||
log_debug("Pinning fully visible API FS");
|
||
|
||
(void) mkdir_p(NSPAWN_PRIVATE_FULLY_VISIBLE_PROCFS, 0755);
|
||
(void) mkdir_p(NSPAWN_PRIVATE_FULLY_VISIBLE_SYSFS, 0755);
|
||
|
||
r = mount_follow_verbose(LOG_ERR, "proc", NSPAWN_PRIVATE_FULLY_VISIBLE_PROCFS, "proc", PROC_DEFAULT_MOUNT_FLAGS, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = mount_follow_verbose(LOG_ERR, "sysfs", NSPAWN_PRIVATE_FULLY_VISIBLE_SYSFS, "sysfs", SYS_DEFAULT_MOUNT_FLAGS, NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int do_wipe_fully_visible_api_fs(void) {
|
||
if (umount2(NSPAWN_PRIVATE_FULLY_VISIBLE_PROCFS, MNT_DETACH) < 0)
|
||
return log_error_errno(errno, "Failed to unmount temporary proc: %m");
|
||
|
||
if (rmdir(NSPAWN_PRIVATE_FULLY_VISIBLE_PROCFS) < 0)
|
||
return log_error_errno(errno, "Failed to remove temporary proc mountpoint: %m");
|
||
|
||
if (umount2(NSPAWN_PRIVATE_FULLY_VISIBLE_SYSFS, MNT_DETACH) < 0)
|
||
return log_error_errno(errno, "Failed to unmount temporary sys: %m");
|
||
|
||
if (rmdir(NSPAWN_PRIVATE_FULLY_VISIBLE_SYSFS) < 0)
|
||
return log_error_errno(errno, "Failed to remove temporary sys mountpoint: %m");
|
||
|
||
return 0;
|
||
}
|
||
|
||
int wipe_fully_visible_api_fs(int mntns_fd) {
|
||
_cleanup_close_ int orig_mntns_fd = -EBADF;
|
||
int r, rr;
|
||
|
||
log_debug("Wiping fully visible API FS");
|
||
|
||
orig_mntns_fd = namespace_open_by_type(NAMESPACE_MOUNT);
|
||
if (orig_mntns_fd < 0)
|
||
return log_error_errno(orig_mntns_fd, "Failed to pin originating mount namespace: %m");
|
||
|
||
r = namespace_enter(/* pidns_fd = */ -EBADF,
|
||
mntns_fd,
|
||
/* netns_fd = */ -EBADF,
|
||
/* userns_fd = */ -EBADF,
|
||
/* root_fd = */ -EBADF);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to enter mount namespace: %m");
|
||
|
||
rr = do_wipe_fully_visible_api_fs();
|
||
|
||
r = namespace_enter(/* pidns_fd = */ -EBADF,
|
||
orig_mntns_fd,
|
||
/* netns_fd = */ -EBADF,
|
||
/* userns_fd = */ -EBADF,
|
||
/* root_fd = */ -EBADF);
|
||
if (r < 0)
|
||
return log_error_errno(r, "Failed to enter original mount namespace: %m");
|
||
|
||
return rr;
|
||
}
|