--- /dev/null
+#pragma once
+
+/***
+ This file is part of systemd.
+
+ Copyright 2017 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/types.h>
+
+/* Note that devpts's gid= parameter parses GIDs as signed values, hence we stay away from the upper half of the 32bit
+ * UID range here. We leave a bit of room at the lower end and a lot of room at the upper end, so that other subsystems
+ * may have their own allocation ranges too. */
+#define UID_SHIFT_PICK_MIN ((uid_t) UINT32_C(0x00080000))
+#define UID_SHIFT_PICK_MAX ((uid_t) UINT32_C(0x6FFF0000))
+
+/* While we are chmod()ing a directory tree, we set the top-level UID base to this "busy" base, so that we can always
+ * recognize trees we are were chmod()ing recursively and got interrupted in */
+#define UID_BUSY_BASE ((uid_t) UINT32_C(0xFFFE0000))
+#define UID_BUSY_MASK ((uid_t) UINT32_C(0xFFFF0000))
#include <sys/acl.h>
#endif
#include <sys/stat.h>
+#include <sys/statvfs.h>
#include <sys/vfs.h>
#include <unistd.h>
#include "acl-util.h"
#include "dirent-util.h"
#include "fd-util.h"
+#include "fs-util.h"
#include "missing.h"
+#include "nspawn-def.h"
#include "nspawn-patch-uid.h"
#include "stat-util.h"
#include "stdio-util.h"
* user namespaces, however their inodes may relate to host resources or only
* valid in the global user namespace, therefore no patching should be applied.
*/
-static int is_fs_fully_userns_compatible(int fd) {
- struct statfs sfs;
-
- assert(fd >= 0);
-
- if (fstatfs(fd, &sfs) < 0)
- return -errno;
-
- return F_TYPE_EQUAL(sfs.f_type, BINFMTFS_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, CGROUP_SUPER_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, CGROUP2_SUPER_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, DEBUGFS_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, DEVPTS_SUPER_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, EFIVARFS_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, HUGETLBFS_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, MQUEUE_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, PROC_SUPER_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, PSTOREFS_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, SELINUX_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, SMACK_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, SECURITYFS_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, BPF_FS_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, TRACEFS_MAGIC) ||
- F_TYPE_EQUAL(sfs.f_type, SYSFS_MAGIC);
+static int is_fs_fully_userns_compatible(const struct statfs *sfs) {
+
+ assert(sfs);
+
+ return F_TYPE_EQUAL(sfs->f_type, BINFMTFS_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, CGROUP_SUPER_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, CGROUP2_SUPER_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, DEBUGFS_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, DEVPTS_SUPER_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, EFIVARFS_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, HUGETLBFS_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, MQUEUE_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, PROC_SUPER_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, PSTOREFS_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, SELINUX_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, SMACK_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, SECURITYFS_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, BPF_FS_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, TRACEFS_MAGIC) ||
+ F_TYPE_EQUAL(sfs->f_type, SYSFS_MAGIC);
}
static int recurse_fd(int fd, bool donate_fd, const struct stat *st, uid_t shift, bool is_toplevel) {
+ _cleanup_closedir_ DIR *d = NULL;
bool changed = false;
+ struct statfs sfs;
int r;
assert(fd >= 0);
- /* We generally want to permit crossing of mount boundaries when patching the UIDs/GIDs. However, we
- * probably shouldn't do this for /proc and /sys if that is already mounted into place. Hence, let's
- * stop the recursion when we hit procfs, sysfs or some other special file systems. */
- r = is_fs_fully_userns_compatible(fd);
+ if (fstatfs(fd, &sfs) < 0)
+ return -errno;
+
+ /* We generally want to permit crossing of mount boundaries when patching the UIDs/GIDs. However, we probably
+ * shouldn't do this for /proc and /sys if that is already mounted into place. Hence, let's stop the recursion
+ * when we hit procfs, sysfs or some other special file systems. */
+
+ r = is_fs_fully_userns_compatible(&sfs);
if (r < 0)
goto finish;
if (r > 0) {
goto finish;
}
- r = patch_fd(fd, NULL, st, shift);
- if (r == -EROFS) {
- _cleanup_free_ char *name = NULL;
-
- if (!is_toplevel) {
- /* When we hit a ready-only subtree we simply skip it, but log about it. */
- (void) fd_get_path(fd, &name);
- log_debug("Skippping read-only file or directory %s.", strna(name));
- r = 0;
- }
-
- goto finish;
- }
- if (r < 0)
- goto finish;
- if (r > 0)
- changed = true;
+ /* Also, if we hit a read-only file system, then don't bother, skip the whole subtree */
+ if ((sfs.f_flags & ST_RDONLY) ||
+ access_fd(fd, W_OK) == -EROFS)
+ goto read_only;
if (S_ISDIR(st->st_mode)) {
- _cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
if (!donate_fd) {
}
}
+ /* After we descended, also patch the directory itself. It's key to do this in this order so that the top-level
+ * directory is patched as very last object in the tree, so that we can use it as quick indicator whether the
+ * tree is properly chown()ed already. */
+ r = patch_fd(d ? dirfd(d) : fd, NULL, st, shift);
+ if (r == -EROFS)
+ goto read_only;
+ if (r > 0)
+ changed = true;
+
r = changed;
+ goto finish;
+
+read_only:
+ if (!is_toplevel) {
+ _cleanup_free_ char *name = NULL;
+
+ /* When we hit a ready-only subtree we simply skip it, but log about it. */
+ (void) fd_get_path(fd, &name);
+ log_debug("Skippping read-only file or directory %s.", strna(name));
+ r = changed;
+ }
finish:
if (donate_fd)
goto finish;
}
+ if (shift == UID_BUSY_BASE) {
+ r = -EINVAL;
+ goto finish;
+ }
+
if (range != 0x10000) {
/* We only support containers with 16bit UID ranges for the patching logic */
r = -EOPNOTSUPP;
if (((uint32_t) (st.st_uid ^ shift) >> 16) == 0)
return 0;
+ /* Before we start recursively chowning, mark the top-level dir as "busy" by chowning it to the "busy"
+ * range. Should we be interrupted in the middle of our work, we'll see it owned by this user and will start
+ * chown()ing it again, unconditionally, as the busy UID is not a valid UID we'd everpick for ourselves. */
+
+ if ((st.st_uid & UID_BUSY_MASK) != UID_BUSY_BASE) {
+ if (fchown(fd,
+ UID_BUSY_BASE | (st.st_uid & ~UID_BUSY_MASK),
+ (gid_t) UID_BUSY_BASE | (st.st_gid & ~(gid_t) UID_BUSY_MASK)) < 0) {
+ r = -errno;
+ goto finish;
+ }
+ }
+
return recurse_fd(fd, donate_fd, &st, shift, true);
finish:
projects / thirdparty / systemd.git / commitdiff
