diff options
Diffstat (limited to 'src/nspawn/nspawn-patch-uid.c')
-rw-r--r-- | src/nspawn/nspawn-patch-uid.c | 469 |
1 files changed, 0 insertions, 469 deletions
diff --git a/src/nspawn/nspawn-patch-uid.c b/src/nspawn/nspawn-patch-uid.c deleted file mode 100644 index c7382d412d..0000000000 --- a/src/nspawn/nspawn-patch-uid.c +++ /dev/null @@ -1,469 +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(©, &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 && !S_ISLNK(st->st_mode)) - r = fchmodat(fd, name, st->st_mode, 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; -} - -static int is_procfs_sysfs_or_suchlike(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, 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 a procfs or sysfs file system. */ - r = is_procfs_sysfs_or_suchlike(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); -} |