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a1164ae3 LP |
1 | /*** |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright 2017 Lennart Poettering | |
5 | ||
6 | systemd is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU Lesser General Public License as published by | |
8 | the Free Software Foundation; either version 2.1 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | systemd is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public License | |
17 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
18 | ***/ | |
19 | ||
20 | #include <sys/types.h> | |
21 | #include <sys/stat.h> | |
22 | #include <fcntl.h> | |
23 | ||
24 | #include "user-util.h" | |
25 | #include "macro.h" | |
26 | #include "fd-util.h" | |
27 | #include "dirent-util.h" | |
28 | #include "chown-recursive.h" | |
29 | ||
30 | static int chown_one(int fd, const char *name, const struct stat *st, uid_t uid, gid_t gid) { | |
31 | int r; | |
32 | ||
33 | assert(fd >= 0); | |
34 | assert(st); | |
35 | ||
36 | if ((!uid_is_valid(uid) || st->st_uid == uid) && | |
37 | (!gid_is_valid(gid) || st->st_gid == gid)) | |
38 | return 0; | |
39 | ||
40 | if (name) | |
41 | r = fchownat(fd, name, uid, gid, AT_SYMLINK_NOFOLLOW); | |
42 | else | |
43 | r = fchown(fd, uid, gid); | |
44 | if (r < 0) | |
45 | return -errno; | |
46 | ||
47 | /* The linux kernel alters the mode in some cases of chown(). Let's undo this. */ | |
48 | if (name) { | |
49 | if (!S_ISLNK(st->st_mode)) | |
50 | r = fchmodat(fd, name, st->st_mode, 0); | |
51 | else /* There's currently no AT_SYMLINK_NOFOLLOW for fchmodat() */ | |
52 | r = 0; | |
53 | } else | |
54 | r = fchmod(fd, st->st_mode); | |
55 | if (r < 0) | |
56 | return -errno; | |
57 | ||
58 | return 1; | |
59 | } | |
60 | ||
61 | static int chown_recursive_internal(int fd, const struct stat *st, uid_t uid, gid_t gid) { | |
62 | bool changed = false; | |
63 | int r; | |
64 | ||
65 | assert(fd >= 0); | |
66 | assert(st); | |
67 | ||
68 | if (S_ISDIR(st->st_mode)) { | |
69 | _cleanup_closedir_ DIR *d = NULL; | |
70 | struct dirent *de; | |
71 | ||
72 | d = fdopendir(fd); | |
73 | if (!d) { | |
74 | r = -errno; | |
75 | goto finish; | |
76 | } | |
77 | fd = -1; | |
78 | ||
79 | FOREACH_DIRENT_ALL(de, d, r = -errno; goto finish) { | |
80 | struct stat fst; | |
81 | ||
82 | if (dot_or_dot_dot(de->d_name)) | |
83 | continue; | |
84 | ||
85 | if (fstatat(dirfd(d), de->d_name, &fst, AT_SYMLINK_NOFOLLOW) < 0) { | |
86 | r = -errno; | |
87 | goto finish; | |
88 | } | |
89 | ||
90 | if (S_ISDIR(fst.st_mode)) { | |
91 | int subdir_fd; | |
92 | ||
93 | subdir_fd = openat(dirfd(d), de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); | |
94 | if (subdir_fd < 0) { | |
95 | r = -errno; | |
96 | goto finish; | |
97 | } | |
98 | ||
99 | r = chown_recursive_internal(subdir_fd, &fst, uid, gid); | |
100 | if (r < 0) | |
101 | goto finish; | |
102 | if (r > 0) | |
103 | changed = true; | |
104 | } else { | |
105 | r = chown_one(dirfd(d), de->d_name, &fst, uid, gid); | |
106 | if (r < 0) | |
107 | goto finish; | |
108 | if (r > 0) | |
109 | changed = true; | |
110 | } | |
111 | } | |
112 | ||
113 | r = chown_one(dirfd(d), NULL, st, uid, gid); | |
114 | } else | |
115 | r = chown_one(fd, NULL, st, uid, gid); | |
116 | if (r < 0) | |
117 | goto finish; | |
118 | ||
119 | r = r > 0 || changed; | |
120 | ||
121 | finish: | |
122 | safe_close(fd); | |
123 | return r; | |
124 | } | |
125 | ||
126 | int path_chown_recursive(const char *path, uid_t uid, gid_t gid) { | |
127 | _cleanup_close_ int fd = -1; | |
128 | struct stat st; | |
129 | int r; | |
130 | ||
131 | fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); | |
132 | if (fd < 0) | |
133 | return -errno; | |
134 | ||
135 | if (!uid_is_valid(uid) && !gid_is_valid(gid)) | |
136 | return 0; /* nothing to do */ | |
137 | ||
138 | if (fstat(fd, &st) < 0) | |
139 | return -errno; | |
140 | ||
141 | /* Let's take a shortcut: if the top-level directory is properly owned, we don't descend into the whole tree, | |
142 | * under the assumption that all is OK anyway. */ | |
143 | ||
144 | if ((!uid_is_valid(uid) || st.st_uid == uid) && | |
145 | (!gid_is_valid(gid) || st.st_gid == gid)) | |
146 | return 0; | |
147 | ||
148 | r = chown_recursive_internal(fd, &st, uid, gid); | |
149 | fd = -1; /* we donated the fd to the call, regardless if it succeeded or failed */ | |
150 | ||
151 | return r; | |
152 | } |