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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
70a5db58 LP |
2 | |
3 | #include <sys/mount.h> | |
4 | ||
5 | #include "btrfs-util.h" | |
6 | #include "fd-util.h" | |
7 | #include "homework-directory.h" | |
2ba38f78 | 8 | #include "homework-mount.h" |
70a5db58 LP |
9 | #include "homework-quota.h" |
10 | #include "mkdir.h" | |
11 | #include "mount-util.h" | |
12 | #include "path-util.h" | |
13 | #include "rm-rf.h" | |
14 | #include "tmpfile-util.h" | |
15 | #include "umask-util.h" | |
cf5115f6 | 16 | #include "user-util.h" |
70a5db58 | 17 | |
e1df968b | 18 | int home_setup_directory(UserRecord *h, HomeSetup *setup) { |
2ba38f78 LP |
19 | const char *ip; |
20 | int r; | |
21 | ||
70a5db58 | 22 | assert(h); |
cf5115f6 | 23 | assert(IN_SET(user_record_storage(h), USER_DIRECTORY, USER_SUBVOLUME)); |
70a5db58 | 24 | assert(setup); |
cf5115f6 | 25 | assert(!setup->undo_mount); |
2ba38f78 LP |
26 | assert(setup->root_fd < 0); |
27 | ||
28 | /* We'll bind mount the image directory to a new mount point where we'll start adjusting it. Only | |
29 | * once that's complete we'll move the thing to its final place eventually. */ | |
30 | r = home_unshare_and_mkdir(); | |
31 | if (r < 0) | |
32 | return r; | |
33 | ||
34 | assert_se(ip = user_record_image_path(h)); | |
35 | ||
36 | r = mount_follow_verbose(LOG_ERR, ip, HOME_RUNTIME_WORK_DIR, NULL, MS_BIND, NULL); | |
37 | if (r < 0) | |
38 | return r; | |
70a5db58 | 39 | |
2ba38f78 LP |
40 | setup->undo_mount = true; |
41 | ||
42 | /* Turn off any form of propagation for this */ | |
43 | r = mount_nofollow_verbose(LOG_ERR, NULL, HOME_RUNTIME_WORK_DIR, NULL, MS_PRIVATE, NULL); | |
44 | if (r < 0) | |
45 | return r; | |
46 | ||
47 | /* Adjust MS_SUID and similar flags */ | |
48 | r = mount_nofollow_verbose(LOG_ERR, NULL, HOME_RUNTIME_WORK_DIR, NULL, MS_BIND|MS_REMOUNT|user_record_mount_flags(h), NULL); | |
49 | if (r < 0) | |
50 | return r; | |
51 | ||
52 | setup->root_fd = open(HOME_RUNTIME_WORK_DIR, O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW); | |
70a5db58 LP |
53 | if (setup->root_fd < 0) |
54 | return log_error_errno(errno, "Failed to open home directory: %m"); | |
55 | ||
56 | return 0; | |
57 | } | |
58 | ||
59 | int home_activate_directory( | |
60 | UserRecord *h, | |
a74e2e44 | 61 | HomeSetup *setup, |
7b78db28 | 62 | PasswordCache *cache, |
70a5db58 LP |
63 | UserRecord **ret_home) { |
64 | ||
65 | _cleanup_(user_record_unrefp) UserRecord *new_home = NULL, *header_home = NULL; | |
2ba38f78 | 66 | const char *hd, *hdo; |
70a5db58 LP |
67 | int r; |
68 | ||
69 | assert(h); | |
70 | assert(IN_SET(user_record_storage(h), USER_DIRECTORY, USER_SUBVOLUME, USER_FSCRYPT)); | |
a74e2e44 | 71 | assert(setup); |
70a5db58 LP |
72 | assert(ret_home); |
73 | ||
70a5db58 | 74 | assert_se(hdo = user_record_home_directory(h)); |
2f82562b | 75 | hd = strdupa_safe(hdo); |
70a5db58 | 76 | |
c00b2ddc | 77 | r = home_setup(h, 0, setup, cache, &header_home); |
70a5db58 LP |
78 | if (r < 0) |
79 | return r; | |
80 | ||
a74e2e44 | 81 | r = home_refresh(h, setup, header_home, cache, NULL, &new_home); |
70a5db58 LP |
82 | if (r < 0) |
83 | return r; | |
84 | ||
cfef46f5 LP |
85 | r = home_extend_embedded_identity(new_home, h, setup); |
86 | if (r < 0) | |
87 | return r; | |
88 | ||
2ba38f78 | 89 | /* Close fd to private mount before moving mount */ |
a74e2e44 | 90 | setup->root_fd = safe_close(setup->root_fd); |
70a5db58 | 91 | |
2ba38f78 LP |
92 | /* We are now done with everything, move the mount into place */ |
93 | r = home_move_mount(NULL, hd); | |
70a5db58 LP |
94 | if (r < 0) |
95 | return r; | |
96 | ||
2ba38f78 | 97 | setup->undo_mount = false; |
70a5db58 | 98 | |
aa0379f1 LP |
99 | setup->do_drop_caches = false; |
100 | ||
70a5db58 LP |
101 | log_info("Everything completed."); |
102 | ||
103 | *ret_home = TAKE_PTR(new_home); | |
104 | return 0; | |
105 | } | |
106 | ||
e1aeaf27 | 107 | int home_create_directory_or_subvolume(UserRecord *h, HomeSetup *setup, UserRecord **ret_home) { |
70a5db58 LP |
108 | _cleanup_(rm_rf_subvolume_and_freep) char *temporary = NULL; |
109 | _cleanup_(user_record_unrefp) UserRecord *new_home = NULL; | |
cf5115f6 | 110 | _cleanup_close_ int mount_fd = -1; |
70a5db58 | 111 | _cleanup_free_ char *d = NULL; |
cf5115f6 | 112 | bool is_subvolume = false; |
70a5db58 LP |
113 | const char *ip; |
114 | int r; | |
115 | ||
116 | assert(h); | |
117 | assert(IN_SET(user_record_storage(h), USER_DIRECTORY, USER_SUBVOLUME)); | |
e1aeaf27 | 118 | assert(setup); |
70a5db58 LP |
119 | assert(ret_home); |
120 | ||
121 | assert_se(ip = user_record_image_path(h)); | |
122 | ||
123 | r = tempfn_random(ip, "homework", &d); | |
124 | if (r < 0) | |
125 | return log_error_errno(r, "Failed to allocate temporary directory: %m"); | |
126 | ||
127 | (void) mkdir_parents(d, 0755); | |
128 | ||
129 | switch (user_record_storage(h)) { | |
130 | ||
131 | case USER_SUBVOLUME: | |
132 | RUN_WITH_UMASK(0077) | |
133 | r = btrfs_subvol_make(d); | |
134 | ||
135 | if (r >= 0) { | |
136 | log_info("Subvolume created."); | |
cf5115f6 | 137 | is_subvolume = true; |
70a5db58 LP |
138 | |
139 | if (h->disk_size != UINT64_MAX) { | |
140 | ||
141 | /* Enable quota for the subvolume we just created. Note we don't check for | |
142 | * errors here and only log about debug level about this. */ | |
143 | r = btrfs_quota_enable(d, true); | |
144 | if (r < 0) | |
145 | log_debug_errno(r, "Failed to enable quota on %s, ignoring: %m", d); | |
146 | ||
147 | r = btrfs_subvol_auto_qgroup(d, 0, false); | |
148 | if (r < 0) | |
149 | log_debug_errno(r, "Failed to set up automatic quota group on %s, ignoring: %m", d); | |
150 | ||
151 | /* Actually configure the quota. We also ignore errors here, but we do log | |
152 | * about them loudly, to keep things discoverable even though we don't | |
153 | * consider lacking quota support in kernel fatal. */ | |
154 | (void) home_update_quota_btrfs(h, d); | |
155 | } | |
156 | ||
157 | break; | |
158 | } | |
159 | if (r != -ENOTTY) | |
160 | return log_error_errno(r, "Failed to create temporary home directory subvolume %s: %m", d); | |
161 | ||
162 | log_info("Creating subvolume %s is not supported, as file system does not support subvolumes. Falling back to regular directory.", d); | |
163 | _fallthrough_; | |
164 | ||
165 | case USER_DIRECTORY: | |
166 | ||
167 | if (mkdir(d, 0700) < 0) | |
168 | return log_error_errno(errno, "Failed to create temporary home directory %s: %m", d); | |
169 | ||
170 | (void) home_update_quota_classic(h, d); | |
171 | break; | |
172 | ||
173 | default: | |
04499a70 | 174 | assert_not_reached(); |
70a5db58 LP |
175 | } |
176 | ||
177 | temporary = TAKE_PTR(d); /* Needs to be destroyed now */ | |
178 | ||
cf5115f6 LP |
179 | /* Let's decouple namespaces now, so that we can possibly mount a UID map mount into |
180 | * /run/systemd/user-home-mount/ that noone will see but us. */ | |
181 | r = home_unshare_and_mkdir(); | |
182 | if (r < 0) | |
183 | return r; | |
184 | ||
e1aeaf27 LP |
185 | setup->root_fd = open(temporary, O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW); |
186 | if (setup->root_fd < 0) | |
70a5db58 LP |
187 | return log_error_errno(errno, "Failed to open temporary home directory: %m"); |
188 | ||
cf5115f6 LP |
189 | /* Try to apply a UID shift, so that the directory is actually owned by "nobody", and is only mapped |
190 | * to the proper UID while active. — Well, that's at least the theory. Unfortunately, only btrfs does | |
191 | * per-subvolume quota. The others do per-uid quota. Which means mapping all home directories to the | |
192 | * same UID of "nobody" makes quota impossible. Hence unless we actually managed to create a btrfs | |
193 | * subvolume for this user we'll map the user's UID to itself. Now you might ask: why bother mapping | |
194 | * at all? It's because we want to restrict the UIDs used on the home directory: we leave all other | |
195 | * UIDs of the homed UID range unmapped, thus making them unavailable to programs accessing the | |
196 | * mount. */ | |
197 | r = home_shift_uid(setup->root_fd, HOME_RUNTIME_WORK_DIR, is_subvolume ? UID_NOBODY : h->uid, h->uid, &mount_fd); | |
198 | if (r > 0) | |
199 | setup->undo_mount = true; /* If uidmaps worked we have a mount to undo again */ | |
200 | ||
201 | if (mount_fd >= 0) { | |
202 | /* If we have established a new mount, then we can use that as new root fd to our home directory. */ | |
203 | safe_close(setup->root_fd); | |
204 | ||
205 | setup->root_fd = fd_reopen(mount_fd, O_RDONLY|O_CLOEXEC|O_DIRECTORY); | |
206 | if (setup->root_fd < 0) | |
207 | return log_error_errno(setup->root_fd, "Unable to convert mount fd into proper directory fd: %m"); | |
208 | ||
209 | mount_fd = safe_close(mount_fd); | |
210 | } | |
211 | ||
e1aeaf27 | 212 | r = home_populate(h, setup->root_fd); |
70a5db58 LP |
213 | if (r < 0) |
214 | return r; | |
215 | ||
e1aeaf27 | 216 | r = home_sync_and_statfs(setup->root_fd, NULL); |
70a5db58 LP |
217 | if (r < 0) |
218 | return r; | |
219 | ||
bfc0cc1a | 220 | r = user_record_clone(h, USER_RECORD_LOAD_MASK_SECRET|USER_RECORD_PERMISSIVE, &new_home); |
70a5db58 LP |
221 | if (r < 0) |
222 | return log_error_errno(r, "Failed to clone record: %m"); | |
223 | ||
224 | r = user_record_add_binding( | |
225 | new_home, | |
226 | user_record_storage(h), | |
227 | ip, | |
228 | SD_ID128_NULL, | |
229 | SD_ID128_NULL, | |
230 | SD_ID128_NULL, | |
231 | NULL, | |
232 | NULL, | |
233 | UINT64_MAX, | |
234 | NULL, | |
235 | NULL, | |
236 | h->uid, | |
237 | (gid_t) h->uid); | |
238 | if (r < 0) | |
239 | return log_error_errno(r, "Failed to add binding to record: %m"); | |
240 | ||
cf5115f6 LP |
241 | setup->root_fd = safe_close(setup->root_fd); |
242 | ||
243 | /* Unmount mapped mount before we move the dir into place */ | |
55166094 LP |
244 | r = home_setup_undo_mount(setup, LOG_ERR); |
245 | if (r < 0) | |
246 | return r; | |
cf5115f6 | 247 | |
70a5db58 LP |
248 | if (rename(temporary, ip) < 0) |
249 | return log_error_errno(errno, "Failed to rename %s to %s: %m", temporary, ip); | |
250 | ||
251 | temporary = mfree(temporary); | |
252 | ||
253 | log_info("Everything completed."); | |
254 | ||
255 | *ret_home = TAKE_PTR(new_home); | |
256 | return 0; | |
257 | } | |
258 | ||
259 | int home_resize_directory( | |
260 | UserRecord *h, | |
e1df968b | 261 | HomeSetupFlags flags, |
70a5db58 | 262 | HomeSetup *setup, |
c00b2ddc | 263 | PasswordCache *cache, |
70a5db58 LP |
264 | UserRecord **ret_home) { |
265 | ||
266 | _cleanup_(user_record_unrefp) UserRecord *embedded_home = NULL, *new_home = NULL; | |
267 | int r; | |
268 | ||
269 | assert(h); | |
270 | assert(setup); | |
271 | assert(ret_home); | |
272 | assert(IN_SET(user_record_storage(h), USER_DIRECTORY, USER_SUBVOLUME, USER_FSCRYPT)); | |
273 | ||
c00b2ddc | 274 | r = home_setup(h, flags, setup, cache, NULL); |
70a5db58 LP |
275 | if (r < 0) |
276 | return r; | |
277 | ||
7b78db28 | 278 | r = home_load_embedded_identity(h, setup->root_fd, NULL, USER_RECONCILE_REQUIRE_NEWER_OR_EQUAL, cache, &embedded_home, &new_home); |
70a5db58 LP |
279 | if (r < 0) |
280 | return r; | |
281 | ||
cf5115f6 LP |
282 | r = home_maybe_shift_uid(h, setup); |
283 | if (r < 0) | |
284 | return r; | |
285 | ||
70a5db58 LP |
286 | r = home_update_quota_auto(h, NULL); |
287 | if (ERRNO_IS_NOT_SUPPORTED(r)) | |
288 | return -ESOCKTNOSUPPORT; /* make recognizable */ | |
289 | if (r < 0) | |
290 | return r; | |
291 | ||
292 | r = home_store_embedded_identity(new_home, setup->root_fd, h->uid, embedded_home); | |
293 | if (r < 0) | |
294 | return r; | |
295 | ||
296 | r = home_extend_embedded_identity(new_home, h, setup); | |
297 | if (r < 0) | |
298 | return r; | |
299 | ||
300 | r = home_sync_and_statfs(setup->root_fd, NULL); | |
301 | if (r < 0) | |
302 | return r; | |
303 | ||
66aa51f8 | 304 | r = home_setup_done(setup); |
70a5db58 LP |
305 | if (r < 0) |
306 | return r; | |
307 | ||
308 | log_info("Everything completed."); | |
309 | ||
310 | *ret_home = TAKE_PTR(new_home); | |
311 | return 0; | |
312 | } |