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Commit | Line | Data |
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ea733a2f | 1 | /* |
22582bb2 | 2 | * Copyright (C) 2003-2013 Kay Sievers <kay@vrfy.org> |
ea733a2f | 3 | * |
55e9959b KS |
4 | * This program is free software: you can redistribute it and/or modify |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation, either version 2 of the License, or | |
7 | * (at your option) any later version. | |
ea733a2f | 8 | * |
55e9959b KS |
9 | * This program is distributed in the hope that it will be useful, |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
ea733a2f GKH |
16 | */ |
17 | ||
24f0605c | 18 | #include <dirent.h> |
07630cea LP |
19 | #include <errno.h> |
20 | #include <fcntl.h> | |
21 | #include <stdbool.h> | |
22 | #include <stddef.h> | |
23 | #include <stdio.h> | |
24 | #include <string.h> | |
32ff5bca | 25 | #include <sys/stat.h> |
07630cea | 26 | #include <unistd.h> |
ea733a2f | 27 | |
f97b34a6 | 28 | #include "format-util.h" |
f4f15635 | 29 | #include "fs-util.h" |
07630cea LP |
30 | #include "selinux-util.h" |
31 | #include "smack-util.h" | |
d054f0a4 | 32 | #include "stdio-util.h" |
07630cea LP |
33 | #include "string-util.h" |
34 | #include "udev.h" | |
9825617b | 35 | |
9ec6e95b | 36 | static int node_symlink(struct udev_device *dev, const char *node, const char *slink) { |
912541b0 KS |
37 | struct stat stats; |
38 | char target[UTIL_PATH_SIZE]; | |
39 | char *s; | |
40 | size_t l; | |
38d70045 | 41 | char slink_tmp[UTIL_PATH_SIZE + 32]; |
912541b0 KS |
42 | int i = 0; |
43 | int tail = 0; | |
44 | int err = 0; | |
45 | ||
46 | /* use relative link */ | |
47 | target[0] = '\0'; | |
48 | while (node[i] && (node[i] == slink[i])) { | |
49 | if (node[i] == '/') | |
50 | tail = i+1; | |
51 | i++; | |
52 | } | |
53 | s = target; | |
54 | l = sizeof(target); | |
55 | while (slink[i] != '\0') { | |
56 | if (slink[i] == '/') | |
d5a89d7d | 57 | l = strpcpy(&s, l, "../"); |
912541b0 KS |
58 | i++; |
59 | } | |
d5a89d7d | 60 | l = strscpy(s, l, &node[tail]); |
912541b0 KS |
61 | if (l == 0) { |
62 | err = -EINVAL; | |
63 | goto exit; | |
64 | } | |
65 | ||
66 | /* preserve link with correct target, do not replace node of other device */ | |
67 | if (lstat(slink, &stats) == 0) { | |
68 | if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) { | |
9f6445e3 | 69 | log_error("conflicting device node '%s' found, link to '%s' will not be created", slink, node); |
2be7287b | 70 | goto exit; |
912541b0 KS |
71 | } else if (S_ISLNK(stats.st_mode)) { |
72 | char buf[UTIL_PATH_SIZE]; | |
73 | int len; | |
74 | ||
912541b0 KS |
75 | len = readlink(slink, buf, sizeof(buf)); |
76 | if (len > 0 && len < (int)sizeof(buf)) { | |
77 | buf[len] = '\0'; | |
090be865 | 78 | if (streq(target, buf)) { |
9f6445e3 | 79 | log_debug("preserve already existing symlink '%s' to '%s'", slink, target); |
c9bc0764 | 80 | label_fix(slink, true, false); |
912541b0 KS |
81 | utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW); |
82 | goto exit; | |
83 | } | |
84 | } | |
85 | } | |
86 | } else { | |
9f6445e3 | 87 | log_debug("creating symlink '%s' to '%s'", slink, target); |
912541b0 | 88 | do { |
d2e54fae | 89 | err = mkdir_parents_label(slink, 0755); |
912541b0 KS |
90 | if (err != 0 && err != -ENOENT) |
91 | break; | |
ecabcf8b | 92 | mac_selinux_create_file_prepare(slink, S_IFLNK); |
912541b0 KS |
93 | err = symlink(target, slink); |
94 | if (err != 0) | |
95 | err = -errno; | |
ecabcf8b | 96 | mac_selinux_create_file_clear(); |
912541b0 KS |
97 | } while (err == -ENOENT); |
98 | if (err == 0) | |
99 | goto exit; | |
100 | } | |
101 | ||
9f6445e3 | 102 | log_debug("atomically replace '%s'", slink); |
38d70045 | 103 | strscpyl(slink_tmp, sizeof(slink_tmp), slink, ".tmp-", udev_device_get_id_filename(dev), NULL); |
912541b0 KS |
104 | unlink(slink_tmp); |
105 | do { | |
d2e54fae | 106 | err = mkdir_parents_label(slink_tmp, 0755); |
912541b0 KS |
107 | if (err != 0 && err != -ENOENT) |
108 | break; | |
ecabcf8b | 109 | mac_selinux_create_file_prepare(slink_tmp, S_IFLNK); |
912541b0 KS |
110 | err = symlink(target, slink_tmp); |
111 | if (err != 0) | |
112 | err = -errno; | |
ecabcf8b | 113 | mac_selinux_create_file_clear(); |
912541b0 KS |
114 | } while (err == -ENOENT); |
115 | if (err != 0) { | |
56f64d95 | 116 | log_error_errno(errno, "symlink '%s' '%s' failed: %m", target, slink_tmp); |
912541b0 KS |
117 | goto exit; |
118 | } | |
119 | err = rename(slink_tmp, slink); | |
120 | if (err != 0) { | |
56f64d95 | 121 | log_error_errno(errno, "rename '%s' '%s' failed: %m", slink_tmp, slink); |
912541b0 KS |
122 | unlink(slink_tmp); |
123 | } | |
fa33d857 | 124 | exit: |
912541b0 | 125 | return err; |
fa33d857 KS |
126 | } |
127 | ||
6c29f2b9 | 128 | /* find device node of device with highest priority */ |
9ec6e95b | 129 | static const char *link_find_prioritized(struct udev_device *dev, bool add, const char *stackdir, char *buf, size_t bufsize) { |
912541b0 KS |
130 | struct udev *udev = udev_device_get_udev(dev); |
131 | DIR *dir; | |
132 | int priority = 0; | |
133 | const char *target = NULL; | |
134 | ||
135 | if (add) { | |
136 | priority = udev_device_get_devlink_priority(dev); | |
d5a89d7d | 137 | strscpy(buf, bufsize, udev_device_get_devnode(dev)); |
912541b0 KS |
138 | target = buf; |
139 | } | |
140 | ||
141 | dir = opendir(stackdir); | |
142 | if (dir == NULL) | |
143 | return target; | |
144 | for (;;) { | |
145 | struct udev_device *dev_db; | |
146 | struct dirent *dent; | |
147 | ||
148 | dent = readdir(dir); | |
149 | if (dent == NULL || dent->d_name[0] == '\0') | |
150 | break; | |
151 | if (dent->d_name[0] == '.') | |
152 | continue; | |
153 | ||
9f6445e3 | 154 | log_debug("found '%s' claiming '%s'", dent->d_name, stackdir); |
912541b0 KS |
155 | |
156 | /* did we find ourself? */ | |
090be865 | 157 | if (streq(dent->d_name, udev_device_get_id_filename(dev))) |
912541b0 KS |
158 | continue; |
159 | ||
dbf61afb | 160 | dev_db = udev_device_new_from_device_id(udev, dent->d_name); |
912541b0 KS |
161 | if (dev_db != NULL) { |
162 | const char *devnode; | |
163 | ||
164 | devnode = udev_device_get_devnode(dev_db); | |
165 | if (devnode != NULL) { | |
912541b0 | 166 | if (target == NULL || udev_device_get_devlink_priority(dev_db) > priority) { |
9f6445e3 | 167 | log_debug("'%s' claims priority %i for '%s'", |
baa30fbc | 168 | udev_device_get_syspath(dev_db), udev_device_get_devlink_priority(dev_db), stackdir); |
912541b0 | 169 | priority = udev_device_get_devlink_priority(dev_db); |
d5a89d7d | 170 | strscpy(buf, bufsize, devnode); |
912541b0 KS |
171 | target = buf; |
172 | } | |
173 | } | |
174 | udev_device_unref(dev_db); | |
175 | } | |
176 | } | |
177 | closedir(dir); | |
178 | return target; | |
aa8734ff KS |
179 | } |
180 | ||
6c29f2b9 | 181 | /* manage "stack of names" with possibly specified device priorities */ |
9ec6e95b | 182 | static void link_update(struct udev_device *dev, const char *slink, bool add) { |
912541b0 KS |
183 | char name_enc[UTIL_PATH_SIZE]; |
184 | char filename[UTIL_PATH_SIZE * 2]; | |
185 | char dirname[UTIL_PATH_SIZE]; | |
186 | const char *target; | |
187 | char buf[UTIL_PATH_SIZE]; | |
188 | ||
4cb72937 | 189 | util_path_encode(slink + strlen("/dev"), name_enc, sizeof(name_enc)); |
d5a89d7d KS |
190 | strscpyl(dirname, sizeof(dirname), "/run/udev/links/", name_enc, NULL); |
191 | strscpyl(filename, sizeof(filename), dirname, "/", udev_device_get_id_filename(dev), NULL); | |
912541b0 | 192 | |
baa30fbc KS |
193 | if (!add && unlink(filename) == 0) |
194 | rmdir(dirname); | |
912541b0 KS |
195 | |
196 | target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf)); | |
197 | if (target == NULL) { | |
9f6445e3 | 198 | log_debug("no reference left, remove '%s'", slink); |
912541b0 | 199 | if (unlink(slink) == 0) |
37d52274 | 200 | rmdir_parents(slink, "/"); |
912541b0 | 201 | } else { |
9f6445e3 | 202 | log_debug("creating link '%s' to '%s'", slink, target); |
38d70045 | 203 | node_symlink(dev, target, slink); |
912541b0 KS |
204 | } |
205 | ||
206 | if (add) { | |
207 | int err; | |
208 | ||
912541b0 KS |
209 | do { |
210 | int fd; | |
211 | ||
3cbd5f6b | 212 | err = mkdir_parents(filename, 0755); |
912541b0 KS |
213 | if (err != 0 && err != -ENOENT) |
214 | break; | |
215 | fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444); | |
216 | if (fd >= 0) | |
217 | close(fd); | |
218 | else | |
219 | err = -errno; | |
220 | } while (err == -ENOENT); | |
221 | } | |
24f0605c KS |
222 | } |
223 | ||
9ec6e95b | 224 | void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev_old) { |
912541b0 KS |
225 | struct udev_list_entry *list_entry; |
226 | ||
227 | /* update possible left-over symlinks */ | |
228 | udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev_old)) { | |
229 | const char *name = udev_list_entry_get_name(list_entry); | |
230 | struct udev_list_entry *list_entry_current; | |
231 | int found; | |
232 | ||
233 | /* check if old link name still belongs to this device */ | |
234 | found = 0; | |
235 | udev_list_entry_foreach(list_entry_current, udev_device_get_devlinks_list_entry(dev)) { | |
236 | const char *name_current = udev_list_entry_get_name(list_entry_current); | |
237 | ||
090be865 | 238 | if (streq(name, name_current)) { |
912541b0 KS |
239 | found = 1; |
240 | break; | |
241 | } | |
242 | } | |
243 | if (found) | |
244 | continue; | |
245 | ||
9f6445e3 | 246 | log_debug("update old name, '%s' no longer belonging to '%s'", |
912541b0 | 247 | name, udev_device_get_devpath(dev)); |
8a173387 | 248 | link_update(dev, name, false); |
912541b0 | 249 | } |
24f0605c KS |
250 | } |
251 | ||
c26547d6 KS |
252 | static int node_permissions_apply(struct udev_device *dev, bool apply, |
253 | mode_t mode, uid_t uid, gid_t gid, | |
254 | struct udev_list *seclabel_list) { | |
912541b0 KS |
255 | const char *devnode = udev_device_get_devnode(dev); |
256 | dev_t devnum = udev_device_get_devnum(dev); | |
257 | struct stat stats; | |
c26547d6 | 258 | struct udev_list_entry *entry; |
912541b0 KS |
259 | int err = 0; |
260 | ||
090be865 | 261 | if (streq(udev_device_get_subsystem(dev), "block")) |
912541b0 KS |
262 | mode |= S_IFBLK; |
263 | else | |
264 | mode |= S_IFCHR; | |
265 | ||
266 | if (lstat(devnode, &stats) != 0) { | |
e1427b13 | 267 | err = log_debug_errno(errno, "can not stat() node '%s' (%m)", devnode); |
912541b0 KS |
268 | goto out; |
269 | } | |
270 | ||
271 | if (((stats.st_mode & S_IFMT) != (mode & S_IFMT)) || (stats.st_rdev != devnum)) { | |
272 | err = -EEXIST; | |
9f6445e3 | 273 | log_debug("found node '%s' with non-matching devnum %s, skip handling", |
baa30fbc | 274 | udev_device_get_devnode(dev), udev_device_get_id_filename(dev)); |
912541b0 KS |
275 | goto out; |
276 | } | |
277 | ||
22582bb2 | 278 | if (apply) { |
b7e2b764 | 279 | bool selinux = false; |
b7e2b764 | 280 | bool smack = false; |
b7e2b764 | 281 | |
48a849ee | 282 | if ((stats.st_mode & 0777) != (mode & 0777) || stats.st_uid != uid || stats.st_gid != gid) { |
9f6445e3 | 283 | log_debug("set permissions %s, %#o, uid=%u, gid=%u", devnode, mode, uid, gid); |
543afdc6 TG |
284 | err = chmod(devnode, mode); |
285 | if (err < 0) | |
56f64d95 | 286 | log_warning_errno(errno, "setting mode of %s to %#o failed: %m", devnode, mode); |
543afdc6 TG |
287 | err = chown(devnode, uid, gid); |
288 | if (err < 0) | |
56f64d95 | 289 | log_warning_errno(errno, "setting owner of %s to uid=%u, gid=%u failed: %m", devnode, uid, gid); |
48a849ee | 290 | } else { |
9f6445e3 | 291 | log_debug("preserve permissions %s, %#o, uid=%u, gid=%u", devnode, mode, uid, gid); |
48a849ee | 292 | } |
c26547d6 | 293 | |
c26547d6 KS |
294 | /* apply SECLABEL{$module}=$label */ |
295 | udev_list_entry_foreach(entry, udev_list_get_entry(seclabel_list)) { | |
296 | const char *name, *label; | |
d53e386d | 297 | int r; |
c26547d6 KS |
298 | |
299 | name = udev_list_entry_get_name(entry); | |
300 | label = udev_list_entry_get_value(entry); | |
301 | ||
302 | if (streq(name, "selinux")) { | |
b7e2b764 | 303 | selinux = true; |
d53e386d | 304 | |
ecabcf8b LP |
305 | r = mac_selinux_apply(devnode, label); |
306 | if (r < 0) | |
da927ba9 | 307 | log_error_errno(r, "SECLABEL: failed to set SELinux label '%s': %m", label); |
463b5dbb KS |
308 | else |
309 | log_debug("SECLABEL: set SELinux label '%s'", label); | |
c26547d6 | 310 | |
9a4e038c | 311 | } else if (streq(name, "smack")) { |
b7e2b764 | 312 | smack = true; |
d53e386d | 313 | |
5ab58c20 | 314 | r = mac_smack_apply(devnode, SMACK_ATTR_ACCESS, label); |
d53e386d | 315 | if (r < 0) |
da927ba9 | 316 | log_error_errno(r, "SECLABEL: failed to set SMACK label '%s': %m", label); |
c26547d6 KS |
317 | else |
318 | log_debug("SECLABEL: set SMACK label '%s'", label); | |
c26547d6 KS |
319 | |
320 | } else | |
321 | log_error("SECLABEL: unknown subsystem, ignoring '%s'='%s'", name, label); | |
322 | } | |
b7e2b764 KS |
323 | |
324 | /* set the defaults */ | |
325 | if (!selinux) | |
2ec62d8e | 326 | mac_selinux_fix(devnode, true, false); |
9a4e038c | 327 | if (!smack) |
5ab58c20 | 328 | mac_smack_apply(devnode, SMACK_ATTR_ACCESS, NULL); |
48a849ee | 329 | } |
912541b0 KS |
330 | |
331 | /* always update timestamp when we re-use the node, like on media change events */ | |
332 | utimensat(AT_FDCWD, devnode, NULL, 0); | |
220893b3 | 333 | out: |
912541b0 | 334 | return err; |
220893b3 KS |
335 | } |
336 | ||
c26547d6 KS |
337 | void udev_node_add(struct udev_device *dev, bool apply, |
338 | mode_t mode, uid_t uid, gid_t gid, | |
339 | struct udev_list *seclabel_list) { | |
e02c6135 | 340 | char filename[sizeof("/dev/block/:") + 2*DECIMAL_STR_MAX(unsigned)]; |
912541b0 | 341 | struct udev_list_entry *list_entry; |
912541b0 | 342 | |
1fa2f38f | 343 | log_debug("handling device node '%s', devnum=%s, mode=%#o, uid="UID_FMT", gid="GID_FMT, |
baa30fbc | 344 | udev_device_get_devnode(dev), udev_device_get_id_filename(dev), mode, uid, gid); |
912541b0 | 345 | |
c26547d6 | 346 | if (node_permissions_apply(dev, apply, mode, uid, gid, seclabel_list) < 0) |
e7f32890 | 347 | return; |
912541b0 KS |
348 | |
349 | /* always add /dev/{block,char}/$major:$minor */ | |
d054f0a4 | 350 | xsprintf(filename, "/dev/%s/%u:%u", |
090be865 | 351 | streq(udev_device_get_subsystem(dev), "block") ? "block" : "char", |
d054f0a4 DM |
352 | major(udev_device_get_devnum(dev)), |
353 | minor(udev_device_get_devnum(dev))); | |
38d70045 | 354 | node_symlink(dev, udev_device_get_devnode(dev), filename); |
912541b0 KS |
355 | |
356 | /* create/update symlinks, add symlinks to name index */ | |
8a173387 KS |
357 | udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) |
358 | link_update(dev, udev_list_entry_get_name(list_entry), true); | |
ea733a2f GKH |
359 | } |
360 | ||
9ec6e95b | 361 | void udev_node_remove(struct udev_device *dev) { |
912541b0 | 362 | struct udev_list_entry *list_entry; |
e02c6135 | 363 | char filename[sizeof("/dev/block/:") + 2*DECIMAL_STR_MAX(unsigned)]; |
912541b0 KS |
364 | |
365 | /* remove/update symlinks, remove symlinks from name index */ | |
366 | udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) | |
8a173387 | 367 | link_update(dev, udev_list_entry_get_name(list_entry), false); |
912541b0 KS |
368 | |
369 | /* remove /dev/{block,char}/$major:$minor */ | |
d054f0a4 | 370 | xsprintf(filename, "/dev/%s/%u:%u", |
090be865 | 371 | streq(udev_device_get_subsystem(dev), "block") ? "block" : "char", |
d054f0a4 DM |
372 | major(udev_device_get_devnum(dev)), |
373 | minor(udev_device_get_devnum(dev))); | |
912541b0 | 374 | unlink(filename); |
ea733a2f | 375 | } |