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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
70a5db58 LP |
2 | |
3 | #include <linux/fs.h> | |
4 | #include <openssl/evp.h> | |
5 | #include <openssl/sha.h> | |
6 | #include <sys/ioctl.h> | |
7 | #include <sys/xattr.h> | |
8 | ||
9 | #include "errno-util.h" | |
10 | #include "fd-util.h" | |
11 | #include "hexdecoct.h" | |
12 | #include "homework-fscrypt.h" | |
13 | #include "homework-quota.h" | |
14 | #include "memory-util.h" | |
15 | #include "missing_keyctl.h" | |
16 | #include "missing_syscall.h" | |
17 | #include "mkdir.h" | |
18 | #include "nulstr-util.h" | |
19 | #include "openssl-util.h" | |
20 | #include "parse-util.h" | |
21 | #include "process-util.h" | |
22 | #include "random-util.h" | |
23 | #include "rm-rf.h" | |
24 | #include "stdio-util.h" | |
25 | #include "strv.h" | |
26 | #include "tmpfile-util.h" | |
27 | #include "user-util.h" | |
28 | #include "xattr-util.h" | |
29 | ||
30 | static int fscrypt_upload_volume_key( | |
31 | const uint8_t key_descriptor[static FS_KEY_DESCRIPTOR_SIZE], | |
32 | const void *volume_key, | |
33 | size_t volume_key_size, | |
34 | key_serial_t where) { | |
35 | ||
36 | _cleanup_free_ char *hex = NULL; | |
37 | const char *description; | |
38 | struct fscrypt_key key; | |
39 | key_serial_t serial; | |
40 | ||
41 | assert(key_descriptor); | |
42 | assert(volume_key); | |
43 | assert(volume_key_size > 0); | |
44 | ||
45 | if (volume_key_size > sizeof(key.raw)) | |
46 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Volume key too long."); | |
47 | ||
48 | hex = hexmem(key_descriptor, FS_KEY_DESCRIPTOR_SIZE); | |
49 | if (!hex) | |
50 | return log_oom(); | |
51 | ||
52 | description = strjoina("fscrypt:", hex); | |
53 | ||
54 | key = (struct fscrypt_key) { | |
55 | .size = volume_key_size, | |
56 | }; | |
57 | memcpy(key.raw, volume_key, volume_key_size); | |
58 | ||
59 | /* Upload to the kernel */ | |
60 | serial = add_key("logon", description, &key, sizeof(key), where); | |
61 | explicit_bzero_safe(&key, sizeof(key)); | |
62 | ||
63 | if (serial < 0) | |
64 | return log_error_errno(errno, "Failed to install master key in keyring: %m"); | |
65 | ||
66 | log_info("Uploaded encryption key to kernel."); | |
67 | ||
68 | return 0; | |
69 | } | |
70 | ||
71 | static void calculate_key_descriptor( | |
72 | const void *key, | |
73 | size_t key_size, | |
74 | uint8_t ret_key_descriptor[static FS_KEY_DESCRIPTOR_SIZE]) { | |
75 | ||
76 | uint8_t hashed[512 / 8] = {}, hashed2[512 / 8] = {}; | |
77 | ||
78 | /* Derive the key descriptor from the volume key via double SHA512, in order to be compatible with e4crypt */ | |
79 | ||
80 | assert_se(SHA512(key, key_size, hashed) == hashed); | |
81 | assert_se(SHA512(hashed, sizeof(hashed), hashed2) == hashed2); | |
82 | ||
83 | assert_cc(sizeof(hashed2) >= FS_KEY_DESCRIPTOR_SIZE); | |
84 | ||
85 | memcpy(ret_key_descriptor, hashed2, FS_KEY_DESCRIPTOR_SIZE); | |
86 | } | |
87 | ||
88 | static int fscrypt_slot_try_one( | |
89 | const char *password, | |
90 | const void *salt, size_t salt_size, | |
91 | const void *encrypted, size_t encrypted_size, | |
92 | const uint8_t match_key_descriptor[static FS_KEY_DESCRIPTOR_SIZE], | |
93 | void **ret_decrypted, size_t *ret_decrypted_size) { | |
94 | ||
95 | ||
96 | _cleanup_(EVP_CIPHER_CTX_freep) EVP_CIPHER_CTX *context = NULL; | |
97 | _cleanup_(erase_and_freep) void *decrypted = NULL; | |
98 | uint8_t key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; | |
99 | int decrypted_size_out1, decrypted_size_out2; | |
100 | uint8_t derived[512 / 8] = {}; | |
101 | size_t decrypted_size; | |
102 | const EVP_CIPHER *cc; | |
103 | int r; | |
104 | ||
105 | assert(password); | |
106 | assert(salt); | |
107 | assert(salt_size > 0); | |
108 | assert(encrypted); | |
109 | assert(encrypted_size > 0); | |
110 | assert(match_key_descriptor); | |
111 | ||
112 | /* Our construction is like this: | |
113 | * | |
114 | * 1. In each key slot we store a salt value plus the encrypted volume key | |
115 | * | |
116 | * 2. Unlocking is via calculating PBKDF2-HMAC-SHA512 of the supplied password (in combination with | |
117 | * the salt), then using the first 256 bit of the hash as key for decrypting the encrypted | |
118 | * volume key in AES256 counter mode. | |
119 | * | |
120 | * 3. Writing a password is similar: calculate PBKDF2-HMAC-SHA512 of the supplied password (in | |
121 | * combination with the salt), then encrypt the volume key in AES256 counter mode with the | |
122 | * resulting hash. | |
123 | */ | |
124 | ||
125 | if (PKCS5_PBKDF2_HMAC( | |
126 | password, strlen(password), | |
127 | salt, salt_size, | |
128 | 0xFFFF, EVP_sha512(), | |
129 | sizeof(derived), derived) != 1) { | |
130 | r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "PBKDF2 failed"); | |
131 | goto finish; | |
132 | } | |
133 | ||
134 | context = EVP_CIPHER_CTX_new(); | |
135 | if (!context) { | |
136 | r = log_oom(); | |
137 | goto finish; | |
138 | } | |
139 | ||
140 | /* We use AES256 in counter mode */ | |
141 | assert_se(cc = EVP_aes_256_ctr()); | |
142 | ||
143 | /* We only use the first half of the derived key */ | |
144 | assert(sizeof(derived) >= (size_t) EVP_CIPHER_key_length(cc)); | |
145 | ||
146 | if (EVP_DecryptInit_ex(context, cc, NULL, derived, NULL) != 1) { | |
147 | r = log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initialize decryption context."); | |
148 | goto finish; | |
149 | } | |
150 | ||
151 | /* Flush out the derived key now, we don't need it anymore */ | |
152 | explicit_bzero_safe(derived, sizeof(derived)); | |
153 | ||
154 | decrypted_size = encrypted_size + EVP_CIPHER_key_length(cc) * 2; | |
155 | decrypted = malloc(decrypted_size); | |
156 | if (!decrypted) | |
157 | return log_oom(); | |
158 | ||
159 | if (EVP_DecryptUpdate(context, (uint8_t*) decrypted, &decrypted_size_out1, encrypted, encrypted_size) != 1) | |
160 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to decrypt volume key."); | |
161 | ||
162 | assert((size_t) decrypted_size_out1 <= decrypted_size); | |
163 | ||
164 | if (EVP_DecryptFinal_ex(context, (uint8_t*) decrypted_size + decrypted_size_out1, &decrypted_size_out2) != 1) | |
165 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to finish decryption of volume key."); | |
166 | ||
167 | assert((size_t) decrypted_size_out1 + (size_t) decrypted_size_out2 < decrypted_size); | |
168 | decrypted_size = (size_t) decrypted_size_out1 + (size_t) decrypted_size_out2; | |
169 | ||
170 | calculate_key_descriptor(decrypted, decrypted_size, key_descriptor); | |
171 | ||
172 | if (memcmp(key_descriptor, match_key_descriptor, FS_KEY_DESCRIPTOR_SIZE) != 0) | |
173 | return -ENOANO; /* don't log here */ | |
174 | ||
175 | r = fscrypt_upload_volume_key(key_descriptor, decrypted, decrypted_size, KEY_SPEC_THREAD_KEYRING); | |
176 | if (r < 0) | |
177 | return r; | |
178 | ||
179 | if (ret_decrypted) | |
180 | *ret_decrypted = TAKE_PTR(decrypted); | |
181 | if (ret_decrypted_size) | |
182 | *ret_decrypted_size = decrypted_size; | |
183 | ||
184 | return 0; | |
185 | ||
186 | finish: | |
187 | explicit_bzero_safe(derived, sizeof(derived)); | |
188 | return r; | |
189 | } | |
190 | ||
191 | static int fscrypt_slot_try_many( | |
192 | char **passwords, | |
193 | const void *salt, size_t salt_size, | |
194 | const void *encrypted, size_t encrypted_size, | |
195 | const uint8_t match_key_descriptor[static FS_KEY_DESCRIPTOR_SIZE], | |
196 | void **ret_decrypted, size_t *ret_decrypted_size) { | |
197 | ||
198 | char **i; | |
199 | int r; | |
200 | ||
201 | STRV_FOREACH(i, passwords) { | |
202 | r = fscrypt_slot_try_one(*i, salt, salt_size, encrypted, encrypted_size, match_key_descriptor, ret_decrypted, ret_decrypted_size); | |
203 | if (r != -ENOANO) | |
204 | return r; | |
205 | } | |
206 | ||
207 | return -ENOANO; | |
208 | } | |
209 | ||
210 | static int fscrypt_setup( | |
7b78db28 | 211 | const PasswordCache *cache, |
70a5db58 LP |
212 | char **password, |
213 | HomeSetup *setup, | |
214 | void **ret_volume_key, | |
215 | size_t *ret_volume_key_size) { | |
216 | ||
217 | _cleanup_free_ char *xattr_buf = NULL; | |
218 | const char *xa; | |
219 | int r; | |
220 | ||
221 | assert(setup); | |
222 | assert(setup->root_fd >= 0); | |
223 | ||
224 | r = flistxattr_malloc(setup->root_fd, &xattr_buf); | |
225 | if (r < 0) | |
226 | return log_error_errno(errno, "Failed to retrieve xattr list: %m"); | |
227 | ||
228 | NULSTR_FOREACH(xa, xattr_buf) { | |
229 | _cleanup_free_ void *salt = NULL, *encrypted = NULL; | |
230 | _cleanup_free_ char *value = NULL; | |
231 | size_t salt_size, encrypted_size; | |
232 | const char *nr, *e; | |
7b78db28 | 233 | char **list; |
70a5db58 LP |
234 | int n; |
235 | ||
236 | /* Check if this xattr has the format 'trusted.fscrypt_slot<nr>' where '<nr>' is a 32bit unsigned integer */ | |
237 | nr = startswith(xa, "trusted.fscrypt_slot"); | |
238 | if (!nr) | |
239 | continue; | |
240 | if (safe_atou32(nr, NULL) < 0) | |
241 | continue; | |
242 | ||
243 | n = fgetxattr_malloc(setup->root_fd, xa, &value); | |
244 | if (n == -ENODATA) /* deleted by now? */ | |
245 | continue; | |
246 | if (n < 0) | |
247 | return log_error_errno(n, "Failed to read %s xattr: %m", xa); | |
248 | ||
249 | e = memchr(value, ':', n); | |
250 | if (!e) | |
251 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "xattr %s lacks ':' separator: %m", xa); | |
252 | ||
253 | r = unbase64mem(value, e - value, &salt, &salt_size); | |
254 | if (r < 0) | |
255 | return log_error_errno(r, "Failed to decode salt of %s: %m", xa); | |
256 | r = unbase64mem(e+1, n - (e - value) - 1, &encrypted, &encrypted_size); | |
257 | if (r < 0) | |
258 | return log_error_errno(r, "Failed to decode encrypted key of %s: %m", xa); | |
259 | ||
7b78db28 LP |
260 | r = -ENOANO; |
261 | FOREACH_POINTER(list, cache->pkcs11_passwords, cache->fido2_passwords, password) { | |
70a5db58 | 262 | r = fscrypt_slot_try_many( |
7b78db28 | 263 | list, |
70a5db58 LP |
264 | salt, salt_size, |
265 | encrypted, encrypted_size, | |
266 | setup->fscrypt_key_descriptor, | |
267 | ret_volume_key, ret_volume_key_size); | |
7b78db28 LP |
268 | if (r != -ENOANO) |
269 | break; | |
270 | } | |
70a5db58 LP |
271 | if (r < 0) { |
272 | if (r != -ENOANO) | |
273 | return r; | |
274 | } else | |
275 | return 0; | |
276 | } | |
277 | ||
278 | return log_error_errno(SYNTHETIC_ERRNO(ENOKEY), "Failed to set up home directory with provided passwords."); | |
279 | } | |
280 | ||
aa0a6214 | 281 | int home_setup_fscrypt( |
70a5db58 | 282 | UserRecord *h, |
7b78db28 | 283 | PasswordCache *cache, |
70a5db58 LP |
284 | HomeSetup *setup) { |
285 | ||
286 | _cleanup_(erase_and_freep) void *volume_key = NULL; | |
287 | struct fscrypt_policy policy = {}; | |
288 | size_t volume_key_size = 0; | |
289 | const char *ip; | |
290 | int r; | |
291 | ||
292 | assert(h); | |
293 | assert(setup); | |
294 | assert(user_record_storage(h) == USER_FSCRYPT); | |
295 | ||
296 | assert_se(ip = user_record_image_path(h)); | |
297 | ||
298 | setup->root_fd = open(ip, O_RDONLY|O_CLOEXEC|O_DIRECTORY); | |
299 | if (setup->root_fd < 0) | |
300 | return log_error_errno(errno, "Failed to open home directory: %m"); | |
301 | ||
302 | if (ioctl(setup->root_fd, FS_IOC_GET_ENCRYPTION_POLICY, &policy) < 0) { | |
303 | if (errno == ENODATA) | |
304 | return log_error_errno(errno, "Home directory %s is not encrypted.", ip); | |
305 | if (ERRNO_IS_NOT_SUPPORTED(errno)) { | |
306 | log_error_errno(errno, "File system does not support fscrypt: %m"); | |
307 | return -ENOLINK; /* make recognizable */ | |
308 | } | |
309 | return log_error_errno(errno, "Failed to acquire encryption policy of %s: %m", ip); | |
310 | } | |
311 | ||
312 | memcpy(setup->fscrypt_key_descriptor, policy.master_key_descriptor, FS_KEY_DESCRIPTOR_SIZE); | |
313 | ||
314 | r = fscrypt_setup( | |
7b78db28 | 315 | cache, |
70a5db58 LP |
316 | h->password, |
317 | setup, | |
318 | &volume_key, | |
319 | &volume_key_size); | |
320 | if (r < 0) | |
321 | return r; | |
322 | ||
323 | /* Also install the access key in the user's own keyring */ | |
324 | ||
325 | if (uid_is_valid(h->uid)) { | |
7e0ed2e9 SB |
326 | r = safe_fork("(sd-addkey)", |
327 | FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG|FORK_LOG|FORK_WAIT|FORK_REOPEN_LOG, | |
328 | NULL); | |
70a5db58 LP |
329 | if (r < 0) |
330 | return log_error_errno(r, "Failed install encryption key in user's keyring: %m"); | |
331 | if (r == 0) { | |
332 | gid_t gid; | |
333 | ||
334 | /* Child */ | |
335 | ||
336 | gid = user_record_gid(h); | |
337 | if (setresgid(gid, gid, gid) < 0) { | |
338 | log_error_errno(errno, "Failed to change GID to " GID_FMT ": %m", gid); | |
339 | _exit(EXIT_FAILURE); | |
340 | } | |
341 | ||
342 | if (setgroups(0, NULL) < 0) { | |
343 | log_error_errno(errno, "Failed to reset auxiliary groups list: %m"); | |
344 | _exit(EXIT_FAILURE); | |
345 | } | |
346 | ||
347 | if (setresuid(h->uid, h->uid, h->uid) < 0) { | |
348 | log_error_errno(errno, "Failed to change UID to " UID_FMT ": %m", h->uid); | |
349 | _exit(EXIT_FAILURE); | |
350 | } | |
351 | ||
352 | r = fscrypt_upload_volume_key( | |
353 | setup->fscrypt_key_descriptor, | |
354 | volume_key, | |
355 | volume_key_size, | |
356 | KEY_SPEC_USER_KEYRING); | |
357 | if (r < 0) | |
358 | _exit(EXIT_FAILURE); | |
359 | ||
360 | _exit(EXIT_SUCCESS); | |
361 | } | |
362 | } | |
363 | ||
364 | return 0; | |
365 | } | |
366 | ||
367 | static int fscrypt_slot_set( | |
368 | int root_fd, | |
369 | const void *volume_key, | |
370 | size_t volume_key_size, | |
371 | const char *password, | |
372 | uint32_t nr) { | |
373 | ||
374 | _cleanup_free_ char *salt_base64 = NULL, *encrypted_base64 = NULL, *joined = NULL; | |
375 | char label[STRLEN("trusted.fscrypt_slot") + DECIMAL_STR_MAX(nr) + 1]; | |
376 | _cleanup_(EVP_CIPHER_CTX_freep) EVP_CIPHER_CTX *context = NULL; | |
377 | int r, encrypted_size_out1, encrypted_size_out2; | |
378 | uint8_t salt[64], derived[512 / 8] = {}; | |
379 | _cleanup_free_ void *encrypted = NULL; | |
380 | const EVP_CIPHER *cc; | |
381 | size_t encrypted_size; | |
382 | ||
383 | r = genuine_random_bytes(salt, sizeof(salt), RANDOM_BLOCK); | |
384 | if (r < 0) | |
385 | return log_error_errno(r, "Failed to generate salt: %m"); | |
386 | ||
387 | if (PKCS5_PBKDF2_HMAC( | |
388 | password, strlen(password), | |
389 | salt, sizeof(salt), | |
390 | 0xFFFF, EVP_sha512(), | |
391 | sizeof(derived), derived) != 1) { | |
392 | r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "PBKDF2 failed"); | |
393 | goto finish; | |
394 | } | |
395 | ||
396 | context = EVP_CIPHER_CTX_new(); | |
397 | if (!context) { | |
398 | r = log_oom(); | |
399 | goto finish; | |
400 | } | |
401 | ||
402 | /* We use AES256 in counter mode */ | |
403 | cc = EVP_aes_256_ctr(); | |
404 | ||
405 | /* We only use the first half of the derived key */ | |
406 | assert(sizeof(derived) >= (size_t) EVP_CIPHER_key_length(cc)); | |
407 | ||
408 | if (EVP_EncryptInit_ex(context, cc, NULL, derived, NULL) != 1) { | |
409 | r = log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initialize encryption context."); | |
410 | goto finish; | |
411 | } | |
412 | ||
413 | /* Flush out the derived key now, we don't need it anymore */ | |
414 | explicit_bzero_safe(derived, sizeof(derived)); | |
415 | ||
416 | encrypted_size = volume_key_size + EVP_CIPHER_key_length(cc) * 2; | |
417 | encrypted = malloc(encrypted_size); | |
418 | if (!encrypted) | |
419 | return log_oom(); | |
420 | ||
421 | if (EVP_EncryptUpdate(context, (uint8_t*) encrypted, &encrypted_size_out1, volume_key, volume_key_size) != 1) | |
422 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to encrypt volume key."); | |
423 | ||
424 | assert((size_t) encrypted_size_out1 <= encrypted_size); | |
425 | ||
426 | if (EVP_EncryptFinal_ex(context, (uint8_t*) encrypted_size + encrypted_size_out1, &encrypted_size_out2) != 1) | |
427 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to finish encryption of volume key."); | |
428 | ||
429 | assert((size_t) encrypted_size_out1 + (size_t) encrypted_size_out2 < encrypted_size); | |
430 | encrypted_size = (size_t) encrypted_size_out1 + (size_t) encrypted_size_out2; | |
431 | ||
432 | r = base64mem(salt, sizeof(salt), &salt_base64); | |
433 | if (r < 0) | |
434 | return log_oom(); | |
435 | ||
436 | r = base64mem(encrypted, encrypted_size, &encrypted_base64); | |
437 | if (r < 0) | |
438 | return log_oom(); | |
439 | ||
440 | joined = strjoin(salt_base64, ":", encrypted_base64); | |
441 | if (!joined) | |
442 | return log_oom(); | |
443 | ||
444 | xsprintf(label, "trusted.fscrypt_slot%" PRIu32, nr); | |
445 | if (fsetxattr(root_fd, label, joined, strlen(joined), 0) < 0) | |
446 | return log_error_errno(errno, "Failed to write xattr %s: %m", label); | |
447 | ||
448 | log_info("Written key slot %s.", label); | |
449 | ||
450 | return 0; | |
451 | ||
452 | finish: | |
453 | explicit_bzero_safe(derived, sizeof(derived)); | |
454 | return r; | |
455 | } | |
456 | ||
457 | int home_create_fscrypt( | |
458 | UserRecord *h, | |
459 | char **effective_passwords, | |
460 | UserRecord **ret_home) { | |
461 | ||
462 | _cleanup_(rm_rf_physical_and_freep) char *temporary = NULL; | |
463 | _cleanup_(user_record_unrefp) UserRecord *new_home = NULL; | |
464 | _cleanup_(erase_and_freep) void *volume_key = NULL; | |
465 | struct fscrypt_policy policy = {}; | |
466 | size_t volume_key_size = 512 / 8; | |
467 | _cleanup_close_ int root_fd = -1; | |
468 | _cleanup_free_ char *d = NULL; | |
469 | uint32_t nr = 0; | |
470 | const char *ip; | |
471 | char **i; | |
472 | int r; | |
473 | ||
474 | assert(h); | |
475 | assert(user_record_storage(h) == USER_FSCRYPT); | |
476 | assert(ret_home); | |
477 | ||
478 | assert_se(ip = user_record_image_path(h)); | |
479 | ||
480 | r = tempfn_random(ip, "homework", &d); | |
481 | if (r < 0) | |
482 | return log_error_errno(r, "Failed to allocate temporary directory: %m"); | |
483 | ||
484 | (void) mkdir_parents(d, 0755); | |
485 | ||
486 | if (mkdir(d, 0700) < 0) | |
487 | return log_error_errno(errno, "Failed to create temporary home directory %s: %m", d); | |
488 | ||
489 | temporary = TAKE_PTR(d); /* Needs to be destroyed now */ | |
490 | ||
491 | root_fd = open(temporary, O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW); | |
492 | if (root_fd < 0) | |
493 | return log_error_errno(errno, "Failed to open temporary home directory: %m"); | |
494 | ||
495 | if (ioctl(root_fd, FS_IOC_GET_ENCRYPTION_POLICY, &policy) < 0) { | |
496 | if (ERRNO_IS_NOT_SUPPORTED(errno)) { | |
497 | log_error_errno(errno, "File system does not support fscrypt: %m"); | |
498 | return -ENOLINK; /* make recognizable */ | |
499 | } | |
500 | if (errno != ENODATA) | |
501 | return log_error_errno(errno, "Failed to get fscrypt policy of directory: %m"); | |
502 | } else | |
503 | return log_error_errno(SYNTHETIC_ERRNO(EBUSY), "Parent of %s already encrypted, refusing.", d); | |
504 | ||
505 | volume_key = malloc(volume_key_size); | |
506 | if (!volume_key) | |
507 | return log_oom(); | |
508 | ||
509 | r = genuine_random_bytes(volume_key, volume_key_size, RANDOM_BLOCK); | |
510 | if (r < 0) | |
511 | return log_error_errno(r, "Failed to acquire volume key: %m"); | |
512 | ||
513 | log_info("Generated volume key of size %zu.", volume_key_size); | |
514 | ||
515 | policy = (struct fscrypt_policy) { | |
516 | .contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS, | |
517 | .filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS, | |
518 | .flags = FS_POLICY_FLAGS_PAD_32, | |
519 | }; | |
520 | ||
521 | calculate_key_descriptor(volume_key, volume_key_size, policy.master_key_descriptor); | |
522 | ||
523 | r = fscrypt_upload_volume_key(policy.master_key_descriptor, volume_key, volume_key_size, KEY_SPEC_THREAD_KEYRING); | |
524 | if (r < 0) | |
525 | return r; | |
526 | ||
527 | log_info("Uploaded volume key to kernel."); | |
528 | ||
529 | if (ioctl(root_fd, FS_IOC_SET_ENCRYPTION_POLICY, &policy) < 0) | |
530 | return log_error_errno(errno, "Failed to set fscrypt policy on directory: %m"); | |
531 | ||
532 | log_info("Encryption policy set."); | |
533 | ||
534 | STRV_FOREACH(i, effective_passwords) { | |
535 | r = fscrypt_slot_set(root_fd, volume_key, volume_key_size, *i, nr); | |
536 | if (r < 0) | |
537 | return r; | |
538 | ||
539 | nr++; | |
540 | } | |
541 | ||
542 | (void) home_update_quota_classic(h, temporary); | |
543 | ||
544 | r = home_populate(h, root_fd); | |
545 | if (r < 0) | |
546 | return r; | |
547 | ||
548 | r = home_sync_and_statfs(root_fd, NULL); | |
549 | if (r < 0) | |
550 | return r; | |
551 | ||
bfc0cc1a | 552 | r = user_record_clone(h, USER_RECORD_LOAD_MASK_SECRET|USER_RECORD_PERMISSIVE, &new_home); |
70a5db58 LP |
553 | if (r < 0) |
554 | return log_error_errno(r, "Failed to clone record: %m"); | |
555 | ||
556 | r = user_record_add_binding( | |
557 | new_home, | |
558 | USER_FSCRYPT, | |
559 | ip, | |
560 | SD_ID128_NULL, | |
561 | SD_ID128_NULL, | |
562 | SD_ID128_NULL, | |
563 | NULL, | |
564 | NULL, | |
565 | UINT64_MAX, | |
566 | NULL, | |
567 | NULL, | |
568 | h->uid, | |
569 | (gid_t) h->uid); | |
570 | if (r < 0) | |
571 | return log_error_errno(r, "Failed to add binding to record: %m"); | |
572 | ||
573 | if (rename(temporary, ip) < 0) | |
574 | return log_error_errno(errno, "Failed to rename %s to %s: %m", temporary, ip); | |
575 | ||
576 | temporary = mfree(temporary); | |
577 | ||
578 | log_info("Everything completed."); | |
579 | ||
580 | *ret_home = TAKE_PTR(new_home); | |
581 | return 0; | |
582 | } | |
583 | ||
584 | int home_passwd_fscrypt( | |
585 | UserRecord *h, | |
586 | HomeSetup *setup, | |
7b78db28 | 587 | PasswordCache *cache, /* the passwords acquired via PKCS#11/FIDO2 security tokens */ |
70a5db58 LP |
588 | char **effective_passwords /* new passwords */) { |
589 | ||
590 | _cleanup_(erase_and_freep) void *volume_key = NULL; | |
591 | _cleanup_free_ char *xattr_buf = NULL; | |
592 | size_t volume_key_size = 0; | |
593 | uint32_t slot = 0; | |
594 | const char *xa; | |
595 | char **p; | |
596 | int r; | |
597 | ||
598 | assert(h); | |
599 | assert(user_record_storage(h) == USER_FSCRYPT); | |
600 | assert(setup); | |
601 | ||
602 | r = fscrypt_setup( | |
7b78db28 | 603 | cache, |
70a5db58 LP |
604 | h->password, |
605 | setup, | |
606 | &volume_key, | |
607 | &volume_key_size); | |
608 | if (r < 0) | |
609 | return r; | |
610 | ||
611 | STRV_FOREACH(p, effective_passwords) { | |
612 | r = fscrypt_slot_set(setup->root_fd, volume_key, volume_key_size, *p, slot); | |
613 | if (r < 0) | |
614 | return r; | |
615 | ||
616 | slot++; | |
617 | } | |
618 | ||
619 | r = flistxattr_malloc(setup->root_fd, &xattr_buf); | |
620 | if (r < 0) | |
621 | return log_error_errno(errno, "Failed to retrieve xattr list: %m"); | |
622 | ||
623 | NULSTR_FOREACH(xa, xattr_buf) { | |
624 | const char *nr; | |
625 | uint32_t z; | |
626 | ||
627 | /* Check if this xattr has the format 'trusted.fscrypt_slot<nr>' where '<nr>' is a 32bit unsigned integer */ | |
628 | nr = startswith(xa, "trusted.fscrypt_slot"); | |
629 | if (!nr) | |
630 | continue; | |
631 | if (safe_atou32(nr, &z) < 0) | |
632 | continue; | |
633 | ||
634 | if (z < slot) | |
635 | continue; | |
636 | ||
637 | if (fremovexattr(setup->root_fd, xa) < 0) | |
638 | ||
639 | if (errno != ENODATA) | |
640 | log_warning_errno(errno, "Failed to remove xattr %s: %m", xa); | |
641 | } | |
642 | ||
643 | return 0; | |
644 | } |