]>
Commit | Line | Data |
---|---|---|
b886d83c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
66dbc325 MZ |
2 | /* |
3 | * Copyright (C) 2005-2010 IBM Corporation | |
4 | * | |
5 | * Author: | |
6 | * Mimi Zohar <zohar@us.ibm.com> | |
7 | * Kylene Hall <kjhall@us.ibm.com> | |
8 | * | |
66dbc325 MZ |
9 | * File: evm_main.c |
10 | * implements evm_inode_setxattr, evm_inode_post_setxattr, | |
11 | * evm_inode_removexattr, and evm_verifyxattr | |
12 | */ | |
13 | ||
3aafb1fb | 14 | #include <linux/init.h> |
66dbc325 | 15 | #include <linux/crypto.h> |
9b97b6cd | 16 | #include <linux/audit.h> |
66dbc325 MZ |
17 | #include <linux/xattr.h> |
18 | #include <linux/integrity.h> | |
3e1be52d | 19 | #include <linux/evm.h> |
50d34394 IM |
20 | #include <linux/magic.h> |
21 | ||
d46eb369 | 22 | #include <crypto/hash.h> |
5feeb611 | 23 | #include <crypto/hash_info.h> |
613317bd | 24 | #include <crypto/algapi.h> |
66dbc325 MZ |
25 | #include "evm.h" |
26 | ||
27 | int evm_initialized; | |
28 | ||
17d7b0af | 29 | static const char * const integrity_status_msg[] = { |
50b97748 | 30 | "pass", "pass_immutable", "fail", "no_label", "no_xattrs", "unknown" |
9b97b6cd | 31 | }; |
d3b33679 | 32 | int evm_hmac_attrs; |
66dbc325 | 33 | |
fa516b66 | 34 | static struct xattr_list evm_config_default_xattrnames[] = { |
66dbc325 | 35 | #ifdef CONFIG_SECURITY_SELINUX |
21af7663 | 36 | {.name = XATTR_NAME_SELINUX}, |
66dbc325 MZ |
37 | #endif |
38 | #ifdef CONFIG_SECURITY_SMACK | |
21af7663 | 39 | {.name = XATTR_NAME_SMACK}, |
3e38df56 | 40 | #ifdef CONFIG_EVM_EXTRA_SMACK_XATTRS |
21af7663 MG |
41 | {.name = XATTR_NAME_SMACKEXEC}, |
42 | {.name = XATTR_NAME_SMACKTRANSMUTE}, | |
43 | {.name = XATTR_NAME_SMACKMMAP}, | |
3e38df56 | 44 | #endif |
2fe5d6de | 45 | #endif |
096b8546 | 46 | #ifdef CONFIG_SECURITY_APPARMOR |
21af7663 | 47 | {.name = XATTR_NAME_APPARMOR}, |
096b8546 | 48 | #endif |
2fe5d6de | 49 | #ifdef CONFIG_IMA_APPRAISE |
21af7663 | 50 | {.name = XATTR_NAME_IMA}, |
66dbc325 | 51 | #endif |
21af7663 | 52 | {.name = XATTR_NAME_CAPS}, |
66dbc325 MZ |
53 | }; |
54 | ||
21af7663 MG |
55 | LIST_HEAD(evm_config_xattrnames); |
56 | ||
7102ebcd MZ |
57 | static int evm_fixmode; |
58 | static int __init evm_set_fixmode(char *str) | |
59 | { | |
60 | if (strncmp(str, "fix", 3) == 0) | |
61 | evm_fixmode = 1; | |
62 | return 0; | |
63 | } | |
64 | __setup("evm=", evm_set_fixmode); | |
65 | ||
d3b33679 DK |
66 | static void __init evm_init_config(void) |
67 | { | |
21af7663 MG |
68 | int i, xattrs; |
69 | ||
70 | xattrs = ARRAY_SIZE(evm_config_default_xattrnames); | |
71 | ||
72 | pr_info("Initialising EVM extended attributes:\n"); | |
73 | for (i = 0; i < xattrs; i++) { | |
74 | pr_info("%s\n", evm_config_default_xattrnames[i].name); | |
75 | list_add_tail(&evm_config_default_xattrnames[i].list, | |
76 | &evm_config_xattrnames); | |
77 | } | |
78 | ||
d3b33679 DK |
79 | #ifdef CONFIG_EVM_ATTR_FSUUID |
80 | evm_hmac_attrs |= EVM_ATTR_FSUUID; | |
81 | #endif | |
82 | pr_info("HMAC attrs: 0x%x\n", evm_hmac_attrs); | |
83 | } | |
84 | ||
ae1ba167 MG |
85 | static bool evm_key_loaded(void) |
86 | { | |
87 | return (bool)(evm_initialized & EVM_KEY_MASK); | |
88 | } | |
89 | ||
15647eb3 DK |
90 | static int evm_find_protected_xattrs(struct dentry *dentry) |
91 | { | |
c6f493d6 | 92 | struct inode *inode = d_backing_inode(dentry); |
21af7663 | 93 | struct xattr_list *xattr; |
15647eb3 DK |
94 | int error; |
95 | int count = 0; | |
96 | ||
5d6c3191 | 97 | if (!(inode->i_opflags & IOP_XATTR)) |
15647eb3 DK |
98 | return -EOPNOTSUPP; |
99 | ||
770f6058 | 100 | list_for_each_entry_lockless(xattr, &evm_config_xattrnames, list) { |
21af7663 | 101 | error = __vfs_getxattr(dentry, inode, xattr->name, NULL, 0); |
15647eb3 DK |
102 | if (error < 0) { |
103 | if (error == -ENODATA) | |
104 | continue; | |
105 | return error; | |
106 | } | |
107 | count++; | |
108 | } | |
109 | ||
110 | return count; | |
111 | } | |
112 | ||
66dbc325 MZ |
113 | /* |
114 | * evm_verify_hmac - calculate and compare the HMAC with the EVM xattr | |
115 | * | |
116 | * Compute the HMAC on the dentry's protected set of extended attributes | |
7102ebcd MZ |
117 | * and compare it against the stored security.evm xattr. |
118 | * | |
119 | * For performance: | |
120 | * - use the previoulsy retrieved xattr value and length to calculate the | |
121 | * HMAC.) | |
122 | * - cache the verification result in the iint, when available. | |
66dbc325 MZ |
123 | * |
124 | * Returns integrity status | |
125 | */ | |
126 | static enum integrity_status evm_verify_hmac(struct dentry *dentry, | |
127 | const char *xattr_name, | |
128 | char *xattr_value, | |
129 | size_t xattr_value_len, | |
130 | struct integrity_iint_cache *iint) | |
131 | { | |
15647eb3 | 132 | struct evm_ima_xattr_data *xattr_data = NULL; |
5feeb611 | 133 | struct signature_v2_hdr *hdr; |
566be59a | 134 | enum integrity_status evm_status = INTEGRITY_PASS; |
5feeb611 | 135 | struct evm_digest digest; |
70946c4a | 136 | struct inode *inode; |
15647eb3 | 137 | int rc, xattr_len; |
66dbc325 | 138 | |
50b97748 MG |
139 | if (iint && (iint->evm_status == INTEGRITY_PASS || |
140 | iint->evm_status == INTEGRITY_PASS_IMMUTABLE)) | |
24e0198e | 141 | return iint->evm_status; |
66dbc325 | 142 | |
6d38ca01 DK |
143 | /* if status is not PASS, try to check again - against -ENOMEM */ |
144 | ||
15647eb3 DK |
145 | /* first need to know the sig type */ |
146 | rc = vfs_getxattr_alloc(dentry, XATTR_NAME_EVM, (char **)&xattr_data, 0, | |
147 | GFP_NOFS); | |
148 | if (rc <= 0) { | |
1f100979 DK |
149 | evm_status = INTEGRITY_FAIL; |
150 | if (rc == -ENODATA) { | |
15647eb3 DK |
151 | rc = evm_find_protected_xattrs(dentry); |
152 | if (rc > 0) | |
153 | evm_status = INTEGRITY_NOLABEL; | |
154 | else if (rc == 0) | |
155 | evm_status = INTEGRITY_NOXATTRS; /* new file */ | |
1f100979 DK |
156 | } else if (rc == -EOPNOTSUPP) { |
157 | evm_status = INTEGRITY_UNKNOWN; | |
15647eb3 | 158 | } |
566be59a MZ |
159 | goto out; |
160 | } | |
66dbc325 | 161 | |
b1aaab22 | 162 | xattr_len = rc; |
15647eb3 DK |
163 | |
164 | /* check value type */ | |
165 | switch (xattr_data->type) { | |
166 | case EVM_XATTR_HMAC: | |
650b29db | 167 | if (xattr_len != sizeof(struct evm_xattr)) { |
b4bfec7f SF |
168 | evm_status = INTEGRITY_FAIL; |
169 | goto out; | |
170 | } | |
5feeb611 MG |
171 | |
172 | digest.hdr.algo = HASH_ALGO_SHA1; | |
15647eb3 | 173 | rc = evm_calc_hmac(dentry, xattr_name, xattr_value, |
5feeb611 | 174 | xattr_value_len, &digest); |
15647eb3 DK |
175 | if (rc) |
176 | break; | |
650b29db | 177 | rc = crypto_memneq(xattr_data->data, digest.digest, |
5feeb611 | 178 | SHA1_DIGEST_SIZE); |
15647eb3 DK |
179 | if (rc) |
180 | rc = -EINVAL; | |
181 | break; | |
182 | case EVM_IMA_XATTR_DIGSIG: | |
50b97748 | 183 | case EVM_XATTR_PORTABLE_DIGSIG: |
5feeb611 MG |
184 | hdr = (struct signature_v2_hdr *)xattr_data; |
185 | digest.hdr.algo = hdr->hash_algo; | |
15647eb3 | 186 | rc = evm_calc_hash(dentry, xattr_name, xattr_value, |
5feeb611 | 187 | xattr_value_len, xattr_data->type, &digest); |
15647eb3 DK |
188 | if (rc) |
189 | break; | |
190 | rc = integrity_digsig_verify(INTEGRITY_KEYRING_EVM, | |
b1aaab22 | 191 | (const char *)xattr_data, xattr_len, |
5feeb611 | 192 | digest.digest, digest.hdr.length); |
15647eb3 | 193 | if (!rc) { |
70946c4a SH |
194 | inode = d_backing_inode(dentry); |
195 | ||
50b97748 MG |
196 | if (xattr_data->type == EVM_XATTR_PORTABLE_DIGSIG) { |
197 | if (iint) | |
198 | iint->flags |= EVM_IMMUTABLE_DIGSIG; | |
199 | evm_status = INTEGRITY_PASS_IMMUTABLE; | |
70946c4a SH |
200 | } else if (!IS_RDONLY(inode) && |
201 | !(inode->i_sb->s_readonly_remount) && | |
202 | !IS_IMMUTABLE(inode)) { | |
c2baec7f DK |
203 | evm_update_evmxattr(dentry, xattr_name, |
204 | xattr_value, | |
205 | xattr_value_len); | |
50b97748 | 206 | } |
15647eb3 DK |
207 | } |
208 | break; | |
209 | default: | |
210 | rc = -EINVAL; | |
211 | break; | |
212 | } | |
213 | ||
214 | if (rc) | |
215 | evm_status = (rc == -ENODATA) ? | |
216 | INTEGRITY_NOXATTRS : INTEGRITY_FAIL; | |
7102ebcd MZ |
217 | out: |
218 | if (iint) | |
219 | iint->evm_status = evm_status; | |
15647eb3 | 220 | kfree(xattr_data); |
7102ebcd | 221 | return evm_status; |
66dbc325 MZ |
222 | } |
223 | ||
224 | static int evm_protected_xattr(const char *req_xattr_name) | |
225 | { | |
66dbc325 MZ |
226 | int namelen; |
227 | int found = 0; | |
21af7663 | 228 | struct xattr_list *xattr; |
66dbc325 MZ |
229 | |
230 | namelen = strlen(req_xattr_name); | |
770f6058 | 231 | list_for_each_entry_lockless(xattr, &evm_config_xattrnames, list) { |
21af7663 MG |
232 | if ((strlen(xattr->name) == namelen) |
233 | && (strncmp(req_xattr_name, xattr->name, namelen) == 0)) { | |
66dbc325 MZ |
234 | found = 1; |
235 | break; | |
236 | } | |
cb723180 | 237 | if (strncmp(req_xattr_name, |
21af7663 | 238 | xattr->name + XATTR_SECURITY_PREFIX_LEN, |
cb723180 MZ |
239 | strlen(req_xattr_name)) == 0) { |
240 | found = 1; | |
241 | break; | |
242 | } | |
66dbc325 | 243 | } |
21af7663 | 244 | |
66dbc325 MZ |
245 | return found; |
246 | } | |
247 | ||
248 | /** | |
249 | * evm_verifyxattr - verify the integrity of the requested xattr | |
250 | * @dentry: object of the verify xattr | |
251 | * @xattr_name: requested xattr | |
252 | * @xattr_value: requested xattr value | |
253 | * @xattr_value_len: requested xattr value length | |
254 | * | |
255 | * Calculate the HMAC for the given dentry and verify it against the stored | |
256 | * security.evm xattr. For performance, use the xattr value and length | |
257 | * previously retrieved to calculate the HMAC. | |
258 | * | |
259 | * Returns the xattr integrity status. | |
260 | * | |
261 | * This function requires the caller to lock the inode's i_mutex before it | |
262 | * is executed. | |
263 | */ | |
264 | enum integrity_status evm_verifyxattr(struct dentry *dentry, | |
265 | const char *xattr_name, | |
2960e6cb DK |
266 | void *xattr_value, size_t xattr_value_len, |
267 | struct integrity_iint_cache *iint) | |
66dbc325 | 268 | { |
ae1ba167 | 269 | if (!evm_key_loaded() || !evm_protected_xattr(xattr_name)) |
66dbc325 MZ |
270 | return INTEGRITY_UNKNOWN; |
271 | ||
2960e6cb | 272 | if (!iint) { |
c6f493d6 | 273 | iint = integrity_iint_find(d_backing_inode(dentry)); |
2960e6cb DK |
274 | if (!iint) |
275 | return INTEGRITY_UNKNOWN; | |
276 | } | |
277 | return evm_verify_hmac(dentry, xattr_name, xattr_value, | |
66dbc325 | 278 | xattr_value_len, iint); |
66dbc325 MZ |
279 | } |
280 | EXPORT_SYMBOL_GPL(evm_verifyxattr); | |
281 | ||
7102ebcd MZ |
282 | /* |
283 | * evm_verify_current_integrity - verify the dentry's metadata integrity | |
284 | * @dentry: pointer to the affected dentry | |
285 | * | |
286 | * Verify and return the dentry's metadata integrity. The exceptions are | |
287 | * before EVM is initialized or in 'fix' mode. | |
288 | */ | |
289 | static enum integrity_status evm_verify_current_integrity(struct dentry *dentry) | |
290 | { | |
c6f493d6 | 291 | struct inode *inode = d_backing_inode(dentry); |
7102ebcd | 292 | |
ae1ba167 | 293 | if (!evm_key_loaded() || !S_ISREG(inode->i_mode) || evm_fixmode) |
7102ebcd MZ |
294 | return 0; |
295 | return evm_verify_hmac(dentry, NULL, NULL, 0, NULL); | |
296 | } | |
297 | ||
a924ce0b MZ |
298 | /* |
299 | * evm_protect_xattr - protect the EVM extended attribute | |
300 | * | |
bf6d0f5d MZ |
301 | * Prevent security.evm from being modified or removed without the |
302 | * necessary permissions or when the existing value is invalid. | |
303 | * | |
304 | * The posix xattr acls are 'system' prefixed, which normally would not | |
305 | * affect security.evm. An interesting side affect of writing posix xattr | |
306 | * acls is their modifying of the i_mode, which is included in security.evm. | |
307 | * For posix xattr acls only, permit security.evm, even if it currently | |
50b97748 | 308 | * doesn't exist, to be updated unless the EVM signature is immutable. |
a924ce0b MZ |
309 | */ |
310 | static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name, | |
311 | const void *xattr_value, size_t xattr_value_len) | |
312 | { | |
313 | enum integrity_status evm_status; | |
314 | ||
315 | if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) { | |
316 | if (!capable(CAP_SYS_ADMIN)) | |
317 | return -EPERM; | |
bf6d0f5d MZ |
318 | } else if (!evm_protected_xattr(xattr_name)) { |
319 | if (!posix_xattr_acl(xattr_name)) | |
320 | return 0; | |
321 | evm_status = evm_verify_current_integrity(dentry); | |
322 | if ((evm_status == INTEGRITY_PASS) || | |
566be59a | 323 | (evm_status == INTEGRITY_NOXATTRS)) |
bf6d0f5d | 324 | return 0; |
9b97b6cd | 325 | goto out; |
bf6d0f5d | 326 | } |
ae1ba167 | 327 | |
a924ce0b | 328 | evm_status = evm_verify_current_integrity(dentry); |
3dcbad52 DK |
329 | if (evm_status == INTEGRITY_NOXATTRS) { |
330 | struct integrity_iint_cache *iint; | |
331 | ||
c6f493d6 | 332 | iint = integrity_iint_find(d_backing_inode(dentry)); |
3dcbad52 DK |
333 | if (iint && (iint->flags & IMA_NEW_FILE)) |
334 | return 0; | |
5101a185 MZ |
335 | |
336 | /* exception for pseudo filesystems */ | |
fc64005c AV |
337 | if (dentry->d_sb->s_magic == TMPFS_MAGIC |
338 | || dentry->d_sb->s_magic == SYSFS_MAGIC) | |
5101a185 MZ |
339 | return 0; |
340 | ||
341 | integrity_audit_msg(AUDIT_INTEGRITY_METADATA, | |
342 | dentry->d_inode, dentry->d_name.name, | |
343 | "update_metadata", | |
344 | integrity_status_msg[evm_status], | |
345 | -EPERM, 0); | |
3dcbad52 | 346 | } |
9b97b6cd MZ |
347 | out: |
348 | if (evm_status != INTEGRITY_PASS) | |
c6f493d6 | 349 | integrity_audit_msg(AUDIT_INTEGRITY_METADATA, d_backing_inode(dentry), |
9b97b6cd MZ |
350 | dentry->d_name.name, "appraise_metadata", |
351 | integrity_status_msg[evm_status], | |
352 | -EPERM, 0); | |
a924ce0b MZ |
353 | return evm_status == INTEGRITY_PASS ? 0 : -EPERM; |
354 | } | |
355 | ||
66dbc325 MZ |
356 | /** |
357 | * evm_inode_setxattr - protect the EVM extended attribute | |
358 | * @dentry: pointer to the affected dentry | |
359 | * @xattr_name: pointer to the affected extended attribute name | |
360 | * @xattr_value: pointer to the new extended attribute value | |
361 | * @xattr_value_len: pointer to the new extended attribute value length | |
362 | * | |
2fb1c9a4 MZ |
363 | * Before allowing the 'security.evm' protected xattr to be updated, |
364 | * verify the existing value is valid. As only the kernel should have | |
365 | * access to the EVM encrypted key needed to calculate the HMAC, prevent | |
366 | * userspace from writing HMAC value. Writing 'security.evm' requires | |
367 | * requires CAP_SYS_ADMIN privileges. | |
66dbc325 MZ |
368 | */ |
369 | int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, | |
370 | const void *xattr_value, size_t xattr_value_len) | |
371 | { | |
2fb1c9a4 MZ |
372 | const struct evm_ima_xattr_data *xattr_data = xattr_value; |
373 | ||
ae1ba167 MG |
374 | /* Policy permits modification of the protected xattrs even though |
375 | * there's no HMAC key loaded | |
376 | */ | |
377 | if (evm_initialized & EVM_ALLOW_METADATA_WRITES) | |
378 | return 0; | |
379 | ||
3b1deef6 DK |
380 | if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) { |
381 | if (!xattr_value_len) | |
382 | return -EINVAL; | |
50b97748 MG |
383 | if (xattr_data->type != EVM_IMA_XATTR_DIGSIG && |
384 | xattr_data->type != EVM_XATTR_PORTABLE_DIGSIG) | |
3b1deef6 DK |
385 | return -EPERM; |
386 | } | |
a924ce0b MZ |
387 | return evm_protect_xattr(dentry, xattr_name, xattr_value, |
388 | xattr_value_len); | |
66dbc325 MZ |
389 | } |
390 | ||
391 | /** | |
392 | * evm_inode_removexattr - protect the EVM extended attribute | |
393 | * @dentry: pointer to the affected dentry | |
394 | * @xattr_name: pointer to the affected extended attribute name | |
395 | * | |
7102ebcd MZ |
396 | * Removing 'security.evm' requires CAP_SYS_ADMIN privileges and that |
397 | * the current value is valid. | |
66dbc325 MZ |
398 | */ |
399 | int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name) | |
400 | { | |
ae1ba167 MG |
401 | /* Policy permits modification of the protected xattrs even though |
402 | * there's no HMAC key loaded | |
403 | */ | |
404 | if (evm_initialized & EVM_ALLOW_METADATA_WRITES) | |
405 | return 0; | |
406 | ||
a924ce0b | 407 | return evm_protect_xattr(dentry, xattr_name, NULL, 0); |
66dbc325 MZ |
408 | } |
409 | ||
523b74b1 DK |
410 | static void evm_reset_status(struct inode *inode) |
411 | { | |
412 | struct integrity_iint_cache *iint; | |
413 | ||
414 | iint = integrity_iint_find(inode); | |
415 | if (iint) | |
416 | iint->evm_status = INTEGRITY_UNKNOWN; | |
417 | } | |
418 | ||
66dbc325 MZ |
419 | /** |
420 | * evm_inode_post_setxattr - update 'security.evm' to reflect the changes | |
421 | * @dentry: pointer to the affected dentry | |
422 | * @xattr_name: pointer to the affected extended attribute name | |
423 | * @xattr_value: pointer to the new extended attribute value | |
424 | * @xattr_value_len: pointer to the new extended attribute value length | |
425 | * | |
426 | * Update the HMAC stored in 'security.evm' to reflect the change. | |
427 | * | |
428 | * No need to take the i_mutex lock here, as this function is called from | |
429 | * __vfs_setxattr_noperm(). The caller of which has taken the inode's | |
430 | * i_mutex lock. | |
431 | */ | |
432 | void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name, | |
433 | const void *xattr_value, size_t xattr_value_len) | |
434 | { | |
ae1ba167 MG |
435 | if (!evm_key_loaded() || (!evm_protected_xattr(xattr_name) |
436 | && !posix_xattr_acl(xattr_name))) | |
66dbc325 MZ |
437 | return; |
438 | ||
523b74b1 DK |
439 | evm_reset_status(dentry->d_inode); |
440 | ||
66dbc325 | 441 | evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len); |
66dbc325 MZ |
442 | } |
443 | ||
444 | /** | |
445 | * evm_inode_post_removexattr - update 'security.evm' after removing the xattr | |
446 | * @dentry: pointer to the affected dentry | |
447 | * @xattr_name: pointer to the affected extended attribute name | |
448 | * | |
449 | * Update the HMAC stored in 'security.evm' to reflect removal of the xattr. | |
7c51bb00 DK |
450 | * |
451 | * No need to take the i_mutex lock here, as this function is called from | |
452 | * vfs_removexattr() which takes the i_mutex. | |
66dbc325 MZ |
453 | */ |
454 | void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name) | |
455 | { | |
ae1ba167 | 456 | if (!evm_key_loaded() || !evm_protected_xattr(xattr_name)) |
66dbc325 MZ |
457 | return; |
458 | ||
523b74b1 DK |
459 | evm_reset_status(dentry->d_inode); |
460 | ||
66dbc325 | 461 | evm_update_evmxattr(dentry, xattr_name, NULL, 0); |
66dbc325 MZ |
462 | } |
463 | ||
817b54aa MZ |
464 | /** |
465 | * evm_inode_setattr - prevent updating an invalid EVM extended attribute | |
466 | * @dentry: pointer to the affected dentry | |
50b97748 MG |
467 | * |
468 | * Permit update of file attributes when files have a valid EVM signature, | |
469 | * except in the case of them having an immutable portable signature. | |
817b54aa MZ |
470 | */ |
471 | int evm_inode_setattr(struct dentry *dentry, struct iattr *attr) | |
472 | { | |
473 | unsigned int ia_valid = attr->ia_valid; | |
474 | enum integrity_status evm_status; | |
475 | ||
ae1ba167 MG |
476 | /* Policy permits modification of the protected attrs even though |
477 | * there's no HMAC key loaded | |
478 | */ | |
479 | if (evm_initialized & EVM_ALLOW_METADATA_WRITES) | |
480 | return 0; | |
481 | ||
a924ce0b | 482 | if (!(ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))) |
817b54aa MZ |
483 | return 0; |
484 | evm_status = evm_verify_current_integrity(dentry); | |
566be59a MZ |
485 | if ((evm_status == INTEGRITY_PASS) || |
486 | (evm_status == INTEGRITY_NOXATTRS)) | |
487 | return 0; | |
c6f493d6 | 488 | integrity_audit_msg(AUDIT_INTEGRITY_METADATA, d_backing_inode(dentry), |
9b97b6cd MZ |
489 | dentry->d_name.name, "appraise_metadata", |
490 | integrity_status_msg[evm_status], -EPERM, 0); | |
566be59a | 491 | return -EPERM; |
817b54aa MZ |
492 | } |
493 | ||
66dbc325 MZ |
494 | /** |
495 | * evm_inode_post_setattr - update 'security.evm' after modifying metadata | |
496 | * @dentry: pointer to the affected dentry | |
497 | * @ia_valid: for the UID and GID status | |
498 | * | |
499 | * For now, update the HMAC stored in 'security.evm' to reflect UID/GID | |
500 | * changes. | |
501 | * | |
502 | * This function is called from notify_change(), which expects the caller | |
503 | * to lock the inode's i_mutex. | |
504 | */ | |
505 | void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) | |
506 | { | |
ae1ba167 | 507 | if (!evm_key_loaded()) |
66dbc325 MZ |
508 | return; |
509 | ||
510 | if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) | |
511 | evm_update_evmxattr(dentry, NULL, NULL, 0); | |
66dbc325 MZ |
512 | } |
513 | ||
cb723180 MZ |
514 | /* |
515 | * evm_inode_init_security - initializes security.evm | |
516 | */ | |
517 | int evm_inode_init_security(struct inode *inode, | |
518 | const struct xattr *lsm_xattr, | |
519 | struct xattr *evm_xattr) | |
520 | { | |
650b29db | 521 | struct evm_xattr *xattr_data; |
cb723180 MZ |
522 | int rc; |
523 | ||
ae1ba167 | 524 | if (!evm_key_loaded() || !evm_protected_xattr(lsm_xattr->name)) |
5a4730ba | 525 | return 0; |
cb723180 MZ |
526 | |
527 | xattr_data = kzalloc(sizeof(*xattr_data), GFP_NOFS); | |
528 | if (!xattr_data) | |
529 | return -ENOMEM; | |
530 | ||
650b29db | 531 | xattr_data->data.type = EVM_XATTR_HMAC; |
cb723180 MZ |
532 | rc = evm_init_hmac(inode, lsm_xattr, xattr_data->digest); |
533 | if (rc < 0) | |
534 | goto out; | |
535 | ||
536 | evm_xattr->value = xattr_data; | |
537 | evm_xattr->value_len = sizeof(*xattr_data); | |
9548906b | 538 | evm_xattr->name = XATTR_EVM_SUFFIX; |
cb723180 MZ |
539 | return 0; |
540 | out: | |
541 | kfree(xattr_data); | |
542 | return rc; | |
543 | } | |
544 | EXPORT_SYMBOL_GPL(evm_inode_init_security); | |
545 | ||
2ce523eb DK |
546 | #ifdef CONFIG_EVM_LOAD_X509 |
547 | void __init evm_load_x509(void) | |
548 | { | |
26ddabfe DK |
549 | int rc; |
550 | ||
551 | rc = integrity_load_x509(INTEGRITY_KEYRING_EVM, CONFIG_EVM_X509_PATH); | |
552 | if (!rc) | |
553 | evm_initialized |= EVM_INIT_X509; | |
2ce523eb DK |
554 | } |
555 | #endif | |
556 | ||
66dbc325 MZ |
557 | static int __init init_evm(void) |
558 | { | |
559 | int error; | |
21af7663 | 560 | struct list_head *pos, *q; |
66dbc325 | 561 | |
d3b33679 DK |
562 | evm_init_config(); |
563 | ||
f4dc3778 DK |
564 | error = integrity_init_keyring(INTEGRITY_KEYRING_EVM); |
565 | if (error) | |
21af7663 | 566 | goto error; |
f4dc3778 | 567 | |
66dbc325 MZ |
568 | error = evm_init_secfs(); |
569 | if (error < 0) { | |
20ee451f | 570 | pr_info("Error registering secfs\n"); |
21af7663 | 571 | goto error; |
66dbc325 | 572 | } |
15647eb3 | 573 | |
21af7663 MG |
574 | error: |
575 | if (error != 0) { | |
576 | if (!list_empty(&evm_config_xattrnames)) { | |
c8b37524 | 577 | list_for_each_safe(pos, q, &evm_config_xattrnames) |
21af7663 | 578 | list_del(pos); |
21af7663 MG |
579 | } |
580 | } | |
66dbc325 | 581 | |
21af7663 | 582 | return error; |
66dbc325 MZ |
583 | } |
584 | ||
66dbc325 | 585 | late_initcall(init_evm); |