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Diffstat (limited to 'src/nspawn/nspawn-patch-uid.c')
-rw-r--r--src/nspawn/nspawn-patch-uid.c481
1 files changed, 0 insertions, 481 deletions
diff --git a/src/nspawn/nspawn-patch-uid.c b/src/nspawn/nspawn-patch-uid.c
deleted file mode 100644
index ded5866d05..0000000000
--- a/src/nspawn/nspawn-patch-uid.c
+++ /dev/null
@@ -1,481 +0,0 @@
-/***
- This file is part of systemd.
-
- Copyright 2016 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 <fcntl.h>
-#include <linux/magic.h>
-#ifdef HAVE_ACL
-#include <sys/acl.h>
-#endif
-#include <sys/stat.h>
-#include <sys/vfs.h>
-#include <unistd.h>
-
-#include "acl-util.h"
-#include "dirent-util.h"
-#include "fd-util.h"
-#include "missing.h"
-#include "nspawn-patch-uid.h"
-#include "stat-util.h"
-#include "stdio-util.h"
-#include "string-util.h"
-#include "strv.h"
-#include "user-util.h"
-
-#ifdef HAVE_ACL
-
-static int get_acl(int fd, const char *name, acl_type_t type, acl_t *ret) {
- char procfs_path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
- acl_t acl;
-
- assert(fd >= 0);
- assert(ret);
-
- if (name) {
- _cleanup_close_ int child_fd = -1;
-
- child_fd = openat(fd, name, O_PATH|O_CLOEXEC|O_NOFOLLOW);
- if (child_fd < 0)
- return -errno;
-
- xsprintf(procfs_path, "/proc/self/fd/%i", child_fd);
- acl = acl_get_file(procfs_path, type);
- } else if (type == ACL_TYPE_ACCESS)
- acl = acl_get_fd(fd);
- else {
- xsprintf(procfs_path, "/proc/self/fd/%i", fd);
- acl = acl_get_file(procfs_path, type);
- }
- if (!acl)
- return -errno;
-
- *ret = acl;
- return 0;
-}
-
-static int set_acl(int fd, const char *name, acl_type_t type, acl_t acl) {
- char procfs_path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
- int r;
-
- assert(fd >= 0);
- assert(acl);
-
- if (name) {
- _cleanup_close_ int child_fd = -1;
-
- child_fd = openat(fd, name, O_PATH|O_CLOEXEC|O_NOFOLLOW);
- if (child_fd < 0)
- return -errno;
-
- xsprintf(procfs_path, "/proc/self/fd/%i", child_fd);
- r = acl_set_file(procfs_path, type, acl);
- } else if (type == ACL_TYPE_ACCESS)
- r = acl_set_fd(fd, acl);
- else {
- xsprintf(procfs_path, "/proc/self/fd/%i", fd);
- r = acl_set_file(procfs_path, type, acl);
- }
- if (r < 0)
- return -errno;
-
- return 0;
-}
-
-static int shift_acl(acl_t acl, uid_t shift, acl_t *ret) {
- _cleanup_(acl_freep) acl_t copy = NULL;
- acl_entry_t i;
- int r;
-
- assert(acl);
- assert(ret);
-
- r = acl_get_entry(acl, ACL_FIRST_ENTRY, &i);
- if (r < 0)
- return -errno;
- while (r > 0) {
- uid_t *old_uid, new_uid;
- bool modify = false;
- acl_tag_t tag;
-
- if (acl_get_tag_type(i, &tag) < 0)
- return -errno;
-
- if (IN_SET(tag, ACL_USER, ACL_GROUP)) {
-
- /* We don't distuingish here between uid_t and gid_t, let's make sure the compiler checks that
- * this is actually OK */
- assert_cc(sizeof(uid_t) == sizeof(gid_t));
-
- old_uid = acl_get_qualifier(i);
- if (!old_uid)
- return -errno;
-
- new_uid = shift | (*old_uid & UINT32_C(0xFFFF));
- if (!uid_is_valid(new_uid))
- return -EINVAL;
-
- modify = new_uid != *old_uid;
- if (modify && !copy) {
- int n;
-
- /* There's no copy of the ACL yet? if so, let's create one, and start the loop from the
- * beginning, so that we copy all entries, starting from the first, this time. */
-
- n = acl_entries(acl);
- if (n < 0)
- return -errno;
-
- copy = acl_init(n);
- if (!copy)
- return -errno;
-
- /* Seek back to the beginning */
- r = acl_get_entry(acl, ACL_FIRST_ENTRY, &i);
- if (r < 0)
- return -errno;
- continue;
- }
- }
-
- if (copy) {
- acl_entry_t new_entry;
-
- if (acl_create_entry(&copy, &new_entry) < 0)
- return -errno;
-
- if (acl_copy_entry(new_entry, i) < 0)
- return -errno;
-
- if (modify)
- if (acl_set_qualifier(new_entry, &new_uid) < 0)
- return -errno;
- }
-
- r = acl_get_entry(acl, ACL_NEXT_ENTRY, &i);
- if (r < 0)
- return -errno;
- }
-
- *ret = copy;
- copy = NULL;
-
- return !!*ret;
-}
-
-static int patch_acls(int fd, const char *name, const struct stat *st, uid_t shift) {
- _cleanup_(acl_freep) acl_t acl = NULL, shifted = NULL;
- bool changed = false;
- int r;
-
- assert(fd >= 0);
- assert(st);
-
- /* ACLs are not supported on symlinks, there's no point in trying */
- if (S_ISLNK(st->st_mode))
- return 0;
-
- r = get_acl(fd, name, ACL_TYPE_ACCESS, &acl);
- if (r == -EOPNOTSUPP)
- return 0;
- if (r < 0)
- return r;
-
- r = shift_acl(acl, shift, &shifted);
- if (r < 0)
- return r;
- if (r > 0) {
- r = set_acl(fd, name, ACL_TYPE_ACCESS, shifted);
- if (r < 0)
- return r;
-
- changed = true;
- }
-
- if (S_ISDIR(st->st_mode)) {
- acl_free(acl);
- acl_free(shifted);
-
- acl = shifted = NULL;
-
- r = get_acl(fd, name, ACL_TYPE_DEFAULT, &acl);
- if (r < 0)
- return r;
-
- r = shift_acl(acl, shift, &shifted);
- if (r < 0)
- return r;
- if (r > 0) {
- r = set_acl(fd, name, ACL_TYPE_DEFAULT, shifted);
- if (r < 0)
- return r;
-
- changed = true;
- }
- }
-
- return changed;
-}
-
-#else
-
-static int patch_acls(int fd, const char *name, const struct stat *st, uid_t shift) {
- return 0;
-}
-
-#endif
-
-static int patch_fd(int fd, const char *name, const struct stat *st, uid_t shift) {
- uid_t new_uid;
- gid_t new_gid;
- bool changed = false;
- int r;
-
- assert(fd >= 0);
- assert(st);
-
- new_uid = shift | (st->st_uid & UINT32_C(0xFFFF));
- new_gid = (gid_t) shift | (st->st_gid & UINT32_C(0xFFFF));
-
- if (!uid_is_valid(new_uid) || !gid_is_valid(new_gid))
- return -EINVAL;
-
- if (st->st_uid != new_uid || st->st_gid != new_gid) {
- if (name)
- r = fchownat(fd, name, new_uid, new_gid, AT_SYMLINK_NOFOLLOW);
- else
- r = fchown(fd, new_uid, new_gid);
- if (r < 0)
- return -errno;
-
- /* The Linux kernel alters the mode in some cases of chown(). Let's undo this. */
- if (name) {
- if (!S_ISLNK(st->st_mode))
- r = fchmodat(fd, name, st->st_mode, 0);
- else /* AT_SYMLINK_NOFOLLOW is not available for fchmodat() */
- r = 0;
- } else
- r = fchmod(fd, st->st_mode);
- if (r < 0)
- return -errno;
-
- changed = true;
- }
-
- r = patch_acls(fd, name, st, shift);
- if (r < 0)
- return r;
-
- return r > 0 || changed;
-}
-
-/*
- * Check if the filesystem is fully compatible with user namespaces or
- * UID/GID patching. Some filesystems in this list can be fully mounted inside
- * 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 recurse_fd(int fd, bool donate_fd, const struct stat *st, uid_t shift, bool is_toplevel) {
- bool changed = false;
- 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 (r < 0)
- goto finish;
- if (r > 0) {
- r = 0; /* don't recurse */
- 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 (S_ISDIR(st->st_mode)) {
- _cleanup_closedir_ DIR *d = NULL;
- struct dirent *de;
-
- if (!donate_fd) {
- int copy;
-
- copy = fcntl(fd, F_DUPFD_CLOEXEC, 3);
- if (copy < 0) {
- r = -errno;
- goto finish;
- }
-
- fd = copy;
- donate_fd = true;
- }
-
- d = fdopendir(fd);
- if (!d) {
- r = -errno;
- goto finish;
- }
- fd = -1;
-
- FOREACH_DIRENT_ALL(de, d, r = -errno; goto finish) {
- struct stat fst;
-
- if (STR_IN_SET(de->d_name, ".", ".."))
- continue;
-
- if (fstatat(dirfd(d), de->d_name, &fst, AT_SYMLINK_NOFOLLOW) < 0) {
- r = -errno;
- goto finish;
- }
-
- if (S_ISDIR(fst.st_mode)) {
- int subdir_fd;
-
- subdir_fd = openat(dirfd(d), de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
- if (subdir_fd < 0) {
- r = -errno;
- goto finish;
-
- }
-
- r = recurse_fd(subdir_fd, true, &fst, shift, false);
- if (r < 0)
- goto finish;
- if (r > 0)
- changed = true;
-
- } else {
- r = patch_fd(dirfd(d), de->d_name, &fst, shift);
- if (r < 0)
- goto finish;
- if (r > 0)
- changed = true;
- }
- }
- }
-
- r = changed;
-
-finish:
- if (donate_fd)
- safe_close(fd);
-
- return r;
-}
-
-static int fd_patch_uid_internal(int fd, bool donate_fd, uid_t shift, uid_t range) {
- struct stat st;
- int r;
-
- assert(fd >= 0);
-
- /* Recursively adjusts the UID/GIDs of all files of a directory tree. This is used to automatically fix up an
- * OS tree to the used user namespace UID range. Note that this automatic adjustment only works for UID ranges
- * following the concept that the upper 16bit of a UID identify the container, and the lower 16bit are the actual
- * UID within the container. */
-
- if ((shift & 0xFFFF) != 0) {
- /* We only support containers where the shift starts at a 2^16 boundary */
- r = -EOPNOTSUPP;
- goto finish;
- }
-
- if (range != 0x10000) {
- /* We only support containers with 16bit UID ranges for the patching logic */
- r = -EOPNOTSUPP;
- goto finish;
- }
-
- if (fstat(fd, &st) < 0) {
- r = -errno;
- goto finish;
- }
-
- if ((uint32_t) st.st_uid >> 16 != (uint32_t) st.st_gid >> 16) {
- /* We only support containers where the uid/gid container ID match */
- r = -EBADE;
- goto finish;
- }
-
- /* Try to detect if the range is already right. Of course, this a pretty drastic optimization, as we assume
- * that if the top-level dir has the right upper 16bit assigned, then everything below will have too... */
- if (((uint32_t) (st.st_uid ^ shift) >> 16) == 0)
- return 0;
-
- return recurse_fd(fd, donate_fd, &st, shift, true);
-
-finish:
- if (donate_fd)
- safe_close(fd);
-
- return r;
-}
-
-int fd_patch_uid(int fd, uid_t shift, uid_t range) {
- return fd_patch_uid_internal(fd, false, shift, range);
-}
-
-int path_patch_uid(const char *path, uid_t shift, uid_t range) {
- int fd;
-
- fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
- if (fd < 0)
- return -errno;
-
- return fd_patch_uid_internal(fd, true, shift, range);
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-01 11:44:34 +0000