15232239991

Committed 24 May 2025 08:01PM UTC coverage: 72.053% (-0.02%) from 72.07%

Build # 15232239991

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docs: add man pages for sd_device_enumerator_[new,ref,unref,unrefp] (#37586)

For #20929.

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83.78

/src/shared/shift-uid.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <sys/statvfs.h>
#include <unistd.h>

#include "acl-util.h"
#include "alloc-util.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "log.h"
#include "missing_magic.h"
#include "shift-uid.h"
#include "stat-util.h"
#include "string-util.h"
#include "user-util.h"

/* 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))

#if HAVE_ACL

static int get_acl(int fd, const char *name, acl_type_t type, acl_t *ret) {
        acl_t acl;

        assert(fd >= 0);
        assert(ret);

        if (name) {
                _cleanup_close_ int child_fd = -EBADF;

                child_fd = openat(fd, name, O_PATH|O_CLOEXEC|O_NOFOLLOW);
                if (child_fd < 0)
                        return -errno;

                acl = acl_get_file(FORMAT_PROC_FD_PATH(child_fd), type);
        } else if (type == ACL_TYPE_ACCESS)
                acl = acl_get_fd(fd);
        else
                acl = acl_get_file(FORMAT_PROC_FD_PATH(fd), 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) {
        int r;

        assert(fd >= 0);
        assert(acl);

        if (name) {
                _cleanup_close_ int child_fd = -EBADF;

                child_fd = openat(fd, name, O_PATH|O_CLOEXEC|O_NOFOLLOW);
                if (child_fd < 0)
                        return -errno;

                r = acl_set_file(FORMAT_PROC_FD_PATH(child_fd), type, acl);
        } else if (type == ACL_TYPE_ACCESS)
                r = acl_set_fd(fd, acl);
        else
                r = acl_set_file(FORMAT_PROC_FD_PATH(fd), 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 distinguish 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 = TAKE_PTR(copy);

        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);

                if (shifted)
                        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 /* Changing the mode of a symlink is not supported by Linux kernel. Don't bother. */
                                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(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, 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);

        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)
                return r;
        if (r > 0) {
                r = 0; /* don't recurse */
                return r;
        }

        /* 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)) {
                d = take_fdopendir(&fd);
                if (!d)
                        return -errno;

                FOREACH_DIRENT_ALL(de, d, return -errno) {
                        struct stat fst;

                        if (dot_or_dot_dot(de->d_name))
                                continue;

                        if (fstatat(dirfd(d), de->d_name, &fst, AT_SYMLINK_NOFOLLOW) < 0)
                                return -errno;

                        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)
                                        return -errno;

                                r = recurse_fd(subdir_fd, &fst, shift, false);
                                if (r < 0)
                                        return r;
                                if (r > 0)
                                        changed = true;

                        } else {
                                r = patch_fd(dirfd(d), de->d_name, &fst, shift);
                                if (r < 0)
                                        return r;
                                if (r > 0)
                                        changed = true;
                        }
                }
        }

        /* 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;

        return changed;

read_only:
        if (!is_toplevel) {
                _cleanup_free_ char *name = NULL;

                /* When we hit a read-only subtree we simply skip it, but log about it. */
                (void) fd_get_path(fd, &name);
                log_debug("Skipping read-only file or directory %s.", strna(name));
                r = changed;
        }

        return r;
}

int path_patch_uid(const char *path, uid_t shift, uid_t range) {
        _cleanup_close_ int fd = -EBADF;
        struct stat st;

        assert(path);

        fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
        if (fd < 0)
                return -errno;

        /* 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 16-bit of a UID identify the container, and the lower 16-bit are the actual
         * UID within the container. */

        /* We only support containers where the shift starts at a 2^16 boundary */
        if ((shift & 0xFFFF) != 0)
                return -EOPNOTSUPP;

        if (shift == UID_BUSY_BASE)
                return -EINVAL;

        /* We only support containers with 16-bit UID ranges for the patching logic */
        if (range != 0x10000)
                return -EOPNOTSUPP;

        if (fstat(fd, &st) < 0)
                return -errno;

        /* We only support containers where the uid/gid container ID match */
        if ((uint32_t) st.st_uid >> 16 != (uint32_t) st.st_gid >> 16)
                return -EBADE;

        /* 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 16-bit assigned, then everything below will have too... */
        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)
                        return -errno;

        return recurse_fd(TAKE_FD(fd), &st, shift, true);
}

1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3	#include <sys/statvfs.h>
4	#include <unistd.h>
5
6	#include "acl-util.h"
7	#include "alloc-util.h"
8	#include "dirent-util.h"
9	#include "fd-util.h"
10	#include "fileio.h"
11	#include "fs-util.h"
12	#include "log.h"
13	#include "missing_magic.h"
14	#include "shift-uid.h"
15	#include "stat-util.h"
16	#include "string-util.h"
17	#include "user-util.h"
18
19	/* While we are chmod()ing a directory tree, we set the top-level UID base to this "busy" base, so that we can always
20	* recognize trees we are were chmod()ing recursively and got interrupted in */
21	#define UID_BUSY_BASE ((uid_t) UINT32_C(0xFFFE0000))
22	#define UID_BUSY_MASK ((uid_t) UINT32_C(0xFFFF0000))
23
24	#if HAVE_ACL
25
26	static int get_acl(int fd, const char name, acl_type_t type, acl_t ret) {	31,804✔
27	acl_t acl;	31,804✔
28
29	assert(fd >= 0);	31,804✔
30	assert(ret);	31,804✔
31
32	if (name) {	31,804✔
33	_cleanup_close_ int child_fd = -EBADF;	27,388✔
34
35	child_fd = openat(fd, name, O_PATH\|O_CLOEXEC\|O_NOFOLLOW);	27,388✔
36	if (child_fd < 0)	27,388✔
37	return -errno;	×
38
39	acl = acl_get_file(FORMAT_PROC_FD_PATH(child_fd), type);	27,388✔
40	} else if (type == ACL_TYPE_ACCESS)	4,416✔
41	acl = acl_get_fd(fd);	2,208✔
42	else
43	acl = acl_get_file(FORMAT_PROC_FD_PATH(fd), type);	2,208✔
44	if (!acl)	31,804✔
45	return -errno;	×
46
47	*ret = acl;	31,804✔
48	return 0;	31,804✔
49	}
50
51	static int set_acl(int fd, const char *name, acl_type_t type, acl_t acl) {	4✔
52	int r;	4✔
53
54	assert(fd >= 0);	4✔
55	assert(acl);	4✔
56
57	if (name) {	4✔
58	_cleanup_close_ int child_fd = -EBADF;	×
59
60	child_fd = openat(fd, name, O_PATH\|O_CLOEXEC\|O_NOFOLLOW);	×
61	if (child_fd < 0)	×
62	return -errno;	×
63
64	r = acl_set_file(FORMAT_PROC_FD_PATH(child_fd), type, acl);	×
65	} else if (type == ACL_TYPE_ACCESS)	4✔
66	r = acl_set_fd(fd, acl);	2✔
67	else
68	r = acl_set_file(FORMAT_PROC_FD_PATH(fd), type, acl);	2✔
69	if (r < 0)	4✔
70	return -errno;	×
71
72	return 0;
73	}
74
75	static int shift_acl(acl_t acl, uid_t shift, acl_t *ret) {	31,804✔
76	_cleanup_(acl_freep) acl_t copy = NULL;	31,804✔
77	acl_entry_t i;	31,804✔
78	int r;	31,804✔
79
80	assert(acl);	31,804✔
81	assert(ret);	31,804✔
82
83	r = acl_get_entry(acl, ACL_FIRST_ENTRY, &i);	31,804✔
84	if (r < 0)	31,804✔
85	return -errno;	×
86	while (r > 0) {	120,618✔
87	uid_t *old_uid, new_uid;	88,814✔
88	bool modify = false;	88,814✔
89	acl_tag_t tag;	88,814✔
90
91	if (acl_get_tag_type(i, &tag) < 0)	88,814✔
92	return -errno;	×
93
94	if (IN_SET(tag, ACL_USER, ACL_GROUP)) {	88,814✔
95
96	/* We don't distinguish here between uid_t and gid_t, let's make sure the compiler checks that
97	* this is actually OK */
98	assert_cc(sizeof(uid_t) == sizeof(gid_t));	12✔
99
100	old_uid = acl_get_qualifier(i);	12✔
101	if (!old_uid)	12✔
102	return -errno;	×
103
104	new_uid = shift \| (*old_uid & UINT32_C(0xFFFF));	12✔
105	if (!uid_is_valid(new_uid))	12✔
106	return -EINVAL;
107
108	modify = new_uid != *old_uid;	12✔
109	if (modify && !copy) {	12✔
110	int n;	4✔
111
112	/* There's no copy of the ACL yet? if so, let's create one, and start the loop from the
113	* beginning, so that we copy all entries, starting from the first, this time. */
114
115	n = acl_entries(acl);	4✔
116	if (n < 0)	4✔
117	return -errno;	×
118
119	copy = acl_init(n);	4✔
120	if (!copy)	4✔
121	return -errno;	×
122
123	/* Seek back to the beginning */
124	r = acl_get_entry(acl, ACL_FIRST_ENTRY, &i);	4✔
125	if (r < 0)	4✔
126	return -errno;	×
127	continue;	4✔
128	}
129	}
130
131	if (copy) {	88,810✔
132	acl_entry_t new_entry;	24✔
133
134	if (acl_create_entry(&copy, &new_entry) < 0)	24✔
135	return -errno;	×
136
137	if (acl_copy_entry(new_entry, i) < 0)	24✔
138	return -errno;	×
139
140	if (modify)	24✔
141	if (acl_set_qualifier(new_entry, &new_uid) < 0)	8✔
142	return -errno;	×
143	}
144
145	r = acl_get_entry(acl, ACL_NEXT_ENTRY, &i);	88,810✔
146	if (r < 0)	88,810✔
147	return -errno;	×
148	}
149
150	*ret = TAKE_PTR(copy);	31,804✔
151
152	return !!*ret;	31,804✔
153	}
154
155	static int patch_acls(int fd, const char name, const struct stat st, uid_t shift) {	38,724✔
156	_cleanup_(acl_freep) acl_t acl = NULL, shifted = NULL;	68,320✔
157	bool changed = false;	38,724✔
158	int r;	38,724✔
159
160	assert(fd >= 0);	38,724✔
161	assert(st);	38,724✔
162
163	/* ACLs are not supported on symlinks, there's no point in trying */
164	if (S_ISLNK(st->st_mode))	38,724✔
165	return 0;
166
167	r = get_acl(fd, name, ACL_TYPE_ACCESS, &acl);	29,596✔
168	if (r == -EOPNOTSUPP)	29,596✔
169	return 0;
170	if (r < 0)	29,596✔
171	return r;
172
173	r = shift_acl(acl, shift, &shifted);	29,596✔
174	if (r < 0)	29,596✔
175	return r;
176	if (r > 0) {	29,596✔
177	r = set_acl(fd, name, ACL_TYPE_ACCESS, shifted);	2✔
178	if (r < 0)	2✔
179	return r;
180
181	changed = true;
182	}
183
184	if (S_ISDIR(st->st_mode)) {	29,596✔
185	acl_free(acl);	2,208✔
186
187	if (shifted)	2,208✔
188	acl_free(shifted);	2✔
189
190	acl = shifted = NULL;	2,208✔
191
192	r = get_acl(fd, name, ACL_TYPE_DEFAULT, &acl);	2,208✔
193	if (r < 0)	2,208✔
194	return r;
195
196	r = shift_acl(acl, shift, &shifted);	2,208✔
197	if (r < 0)	2,208✔
198	return r;
199	if (r > 0) {	2,208✔
200	r = set_acl(fd, name, ACL_TYPE_DEFAULT, shifted);	2✔
201	if (r < 0)	2✔
202	return r;
203
204	changed = true;
205	}
206	}
207
208	return changed;	29,596✔
209	}
210
211	#else
212
213	static int patch_acls(int fd, const char name, const struct stat st, uid_t shift) {
214	return 0;
215	}
216
217	#endif
218
219	static int patch_fd(int fd, const char name, const struct stat st, uid_t shift) {	38,724✔
220	uid_t new_uid;	38,724✔
221	gid_t new_gid;	38,724✔
222	bool changed = false;	38,724✔
223	int r;	38,724✔
224
225	assert(fd >= 0);	38,724✔
226	assert(st);	38,724✔
227
228	new_uid = shift \| (st->st_uid & UINT32_C(0xFFFF));	38,724✔
229	new_gid = (gid_t) shift \| (st->st_gid & UINT32_C(0xFFFF));	38,724✔
230
231	if (!uid_is_valid(new_uid) \|\| !gid_is_valid(new_gid))	77,448✔
232	return -EINVAL;	×
233
234	if (st->st_uid != new_uid \|\| st->st_gid != new_gid) {	38,724✔
235	if (name)	36,580✔
236	r = fchownat(fd, name, new_uid, new_gid, AT_SYMLINK_NOFOLLOW);	34,372✔
237	else
238	r = fchown(fd, new_uid, new_gid);	2,208✔
239	if (r < 0)	36,580✔
240	return -errno;	×
241
242	/* The Linux kernel alters the mode in some cases of chown(). Let's undo this. */
243	if (name) {	36,580✔
244	if (!S_ISLNK(st->st_mode))	34,372✔
245	r = fchmodat(fd, name, st->st_mode, 0);	25,244✔
246	else /* Changing the mode of a symlink is not supported by Linux kernel. Don't bother. */
247	r = 0;
248	} else
249	r = fchmod(fd, st->st_mode);	2,208✔
250	if (r < 0)	27,452✔
251	return -errno;	×
252
253	changed = true;
254	}
255
256	r = patch_acls(fd, name, st, shift);	38,724✔
257	if (r < 0)	38,724✔
258	return r;
259
260	return r > 0 \|\| changed;	38,724✔
261	}
262
263	/*
264	* Check if the filesystem is fully compatible with user namespaces or
265	* UID/GID patching. Some filesystems in this list can be fully mounted inside
266	* user namespaces, however their inodes may relate to host resources or only
267	* valid in the global user namespace, therefore no patching should be applied.
268	*/
269	static int is_fs_fully_userns_compatible(const struct statfs *sfs) {	2,208✔
270
271	assert(sfs);	2,208✔
272
273	return F_TYPE_EQUAL(sfs->f_type, BINFMTFS_MAGIC) \|\|	2,208✔
274	F_TYPE_EQUAL(sfs->f_type, CGROUP_SUPER_MAGIC) \|\|	2,208✔
275	F_TYPE_EQUAL(sfs->f_type, CGROUP2_SUPER_MAGIC) \|\|	2,208✔
276	F_TYPE_EQUAL(sfs->f_type, DEBUGFS_MAGIC) \|\|	2,208✔
277	F_TYPE_EQUAL(sfs->f_type, DEVPTS_SUPER_MAGIC) \|\|	2,208✔
278	F_TYPE_EQUAL(sfs->f_type, EFIVARFS_MAGIC) \|\|	2,208✔
279	F_TYPE_EQUAL(sfs->f_type, HUGETLBFS_MAGIC) \|\|	2,208✔
280	F_TYPE_EQUAL(sfs->f_type, MQUEUE_MAGIC) \|\|	2,208✔
281	F_TYPE_EQUAL(sfs->f_type, PROC_SUPER_MAGIC) \|\|	2,208✔
282	F_TYPE_EQUAL(sfs->f_type, PSTOREFS_MAGIC) \|\|	2,208✔
283	F_TYPE_EQUAL(sfs->f_type, SELINUX_MAGIC) \|\|	2,208✔
284	F_TYPE_EQUAL(sfs->f_type, SMACK_MAGIC) \|\|	2,208✔
285	F_TYPE_EQUAL(sfs->f_type, SECURITYFS_MAGIC) \|\|	2,208✔
286	F_TYPE_EQUAL(sfs->f_type, BPF_FS_MAGIC) \|\|	2,208✔
287	F_TYPE_EQUAL(sfs->f_type, TRACEFS_MAGIC) \|\|	4,416✔
288	F_TYPE_EQUAL(sfs->f_type, SYSFS_MAGIC);
289	}
290
291	static int recurse_fd(int fd, const struct stat *st, uid_t shift, bool is_toplevel) {	2,208✔
292	_cleanup_closedir_ DIR *d = NULL;	4,416✔
293	bool changed = false;	2,208✔
294	struct statfs sfs;	2,208✔
295	int r;	2,208✔
296
297	assert(fd >= 0);	2,208✔
298
299	if (fstatfs(fd, &sfs) < 0)	2,208✔
300	return -errno;	×
301
302	/* We generally want to permit crossing of mount boundaries when patching the UIDs/GIDs. However, we probably
303	* shouldn't do this for /proc and /sys if that is already mounted into place. Hence, let's stop the recursion
304	* when we hit procfs, sysfs or some other special file systems. */
305
306	r = is_fs_fully_userns_compatible(&sfs);	2,208✔
307	if (r < 0)	2,208✔
308	return r;
309	if (r > 0) {	2,208✔
310	r = 0; /* don't recurse */	2,208✔
311	return r;
312	}
313
314	/* Also, if we hit a read-only file system, then don't bother, skip the whole subtree */
315	if ((sfs.f_flags & ST_RDONLY) \|\|	4,416✔
316	access_fd(fd, W_OK) == -EROFS)	2,208✔
317	goto read_only;	×
318
319	if (S_ISDIR(st->st_mode)) {	2,208✔
320	d = take_fdopendir(&fd);	2,208✔
321	if (!d)	2,208✔
322	return -errno;	×
323
324	FOREACH_DIRENT_ALL(de, d, return -errno) {	45,340✔
325	struct stat fst;	43,132✔
326
327	if (dot_or_dot_dot(de->d_name))	43,132✔
328	continue;	4,416✔
329
330	if (fstatat(dirfd(d), de->d_name, &fst, AT_SYMLINK_NOFOLLOW) < 0)	38,716✔
331	return -errno;	×
332
333	if (S_ISDIR(fst.st_mode)) {	38,716✔
334	int subdir_fd;	2,200✔
335
336	subdir_fd = openat(dirfd(d), de->d_name, O_RDONLY\|O_NONBLOCK\|O_DIRECTORY\|O_CLOEXEC\|O_NOFOLLOW\|O_NOATIME);	2,200✔
337	if (subdir_fd < 0)	2,200✔
338	return -errno;	×
339
340	r = recurse_fd(subdir_fd, &fst, shift, false);	2,200✔
341	if (r < 0)	2,200✔
342	return r;
343	if (r > 0)	2,200✔
344	changed = true;	2,200✔
345
346	} else {
347	r = patch_fd(dirfd(d), de->d_name, &fst, shift);	36,516✔
348	if (r < 0)	36,516✔
349	return r;
350	if (r > 0)	36,516✔
351	changed = true;	34,372✔
352	}
353	}
354	}
355
356	/* After we descended, also patch the directory itself. It's key to do this in this order so that the top-level
357	* directory is patched as very last object in the tree, so that we can use it as quick indicator whether the
358	* tree is properly chown()ed already. */
359	r = patch_fd(d ? dirfd(d) : fd, NULL, st, shift);	2,208✔
360	if (r == -EROFS)	2,208✔
361	goto read_only;	×
362	if (r > 0)	2,208✔
363	changed = true;	2,208✔
364
365	return changed;	2,208✔
366
367	read_only:	×
368	if (!is_toplevel) {	×
369	_cleanup_free_ char *name = NULL;	×
370
371	/* When we hit a read-only subtree we simply skip it, but log about it. */
372	(void) fd_get_path(fd, &name);	×
373	log_debug("Skipping read-only file or directory %s.", strna(name));	×
374	r = changed;	×
375	}
376
377	return r;
378	}
379
380	int path_patch_uid(const char *path, uid_t shift, uid_t range) {	10✔
381	_cleanup_close_ int fd = -EBADF;	10✔
382	struct stat st;	10✔
383
384	assert(path);	10✔
385
386	fd = open(path, O_RDONLY\|O_NONBLOCK\|O_DIRECTORY\|O_CLOEXEC\|O_NOFOLLOW\|O_NOATIME);	10✔
387	if (fd < 0)	10✔
388	return -errno;	×
389
390	/* Recursively adjusts the UID/GIDs of all files of a directory tree. This is used to automatically fix up an
391	* OS tree to the used user namespace UID range. Note that this automatic adjustment only works for UID ranges
392	* following the concept that the upper 16-bit of a UID identify the container, and the lower 16-bit are the actual
393	* UID within the container. */
394
395	/* We only support containers where the shift starts at a 2^16 boundary */
396	if ((shift & 0xFFFF) != 0)	10✔
397	return -EOPNOTSUPP;
398
399	if (shift == UID_BUSY_BASE)	10✔
400	return -EINVAL;
401
402	/* We only support containers with 16-bit UID ranges for the patching logic */
403	if (range != 0x10000)	10✔
404	return -EOPNOTSUPP;
405
406	if (fstat(fd, &st) < 0)	10✔
407	return -errno;	×
408
409	/* We only support containers where the uid/gid container ID match */
410	if ((uint32_t) st.st_uid >> 16 != (uint32_t) st.st_gid >> 16)	10✔
411	return -EBADE;
412
413	/* Try to detect if the range is already right. Of course, this a pretty drastic optimization, as we assume
414	* that if the top-level dir has the right upper 16-bit assigned, then everything below will have too... */
415	if (((uint32_t) (st.st_uid ^ shift) >> 16) == 0)	10✔
416	return 0;
417
418	/* Before we start recursively chowning, mark the top-level dir as "busy" by chowning it to the "busy"
419	* range. Should we be interrupted in the middle of our work, we'll see it owned by this user and will start
420	* chown()ing it again, unconditionally, as the busy UID is not a valid UID we'd everpick for ourselves. */
421
422	if ((st.st_uid & UID_BUSY_MASK) != UID_BUSY_BASE)	8✔
423	if (fchown(fd,	8✔
424	UID_BUSY_BASE \| (st.st_uid & ~UID_BUSY_MASK),	8✔
425	(gid_t) UID_BUSY_BASE \| (st.st_gid & ~(gid_t) UID_BUSY_MASK)) < 0)	8✔
426	return -errno;	×
427
428	return recurse_fd(TAKE_FD(fd), &st, shift, true);	8✔
429	}

systemd / systemd / 15232239991

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