x86/mm/pat: Don't report PAT on CPUs that don't support it
[linux/fpc-iii.git] / security / integrity / ima / ima_appraise.c
blob5d0785cfe06387f65a53f84f2832007d77a7932c
1 /*
2 * Copyright (C) 2011 IBM Corporation
4 * Author:
5 * Mimi Zohar <zohar@us.ibm.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, version 2 of the License.
11 #include <linux/module.h>
12 #include <linux/file.h>
13 #include <linux/fs.h>
14 #include <linux/xattr.h>
15 #include <linux/magic.h>
16 #include <linux/ima.h>
17 #include <linux/evm.h>
19 #include "ima.h"
21 static int __init default_appraise_setup(char *str)
23 if (strncmp(str, "off", 3) == 0)
24 ima_appraise = 0;
25 else if (strncmp(str, "log", 3) == 0)
26 ima_appraise = IMA_APPRAISE_LOG;
27 else if (strncmp(str, "fix", 3) == 0)
28 ima_appraise = IMA_APPRAISE_FIX;
29 return 1;
32 __setup("ima_appraise=", default_appraise_setup);
35 * ima_must_appraise - set appraise flag
37 * Return 1 to appraise
39 int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
41 if (!ima_appraise)
42 return 0;
44 return ima_match_policy(inode, func, mask, IMA_APPRAISE, NULL);
47 static int ima_fix_xattr(struct dentry *dentry,
48 struct integrity_iint_cache *iint)
50 int rc, offset;
51 u8 algo = iint->ima_hash->algo;
53 if (algo <= HASH_ALGO_SHA1) {
54 offset = 1;
55 iint->ima_hash->xattr.sha1.type = IMA_XATTR_DIGEST;
56 } else {
57 offset = 0;
58 iint->ima_hash->xattr.ng.type = IMA_XATTR_DIGEST_NG;
59 iint->ima_hash->xattr.ng.algo = algo;
61 rc = __vfs_setxattr_noperm(dentry, XATTR_NAME_IMA,
62 &iint->ima_hash->xattr.data[offset],
63 (sizeof(iint->ima_hash->xattr) - offset) +
64 iint->ima_hash->length, 0);
65 return rc;
68 /* Return specific func appraised cached result */
69 enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
70 enum ima_hooks func)
72 switch (func) {
73 case MMAP_CHECK:
74 return iint->ima_mmap_status;
75 case BPRM_CHECK:
76 return iint->ima_bprm_status;
77 case FILE_CHECK:
78 case POST_SETATTR:
79 return iint->ima_file_status;
80 case MODULE_CHECK ... MAX_CHECK - 1:
81 default:
82 return iint->ima_read_status;
86 static void ima_set_cache_status(struct integrity_iint_cache *iint,
87 enum ima_hooks func,
88 enum integrity_status status)
90 switch (func) {
91 case MMAP_CHECK:
92 iint->ima_mmap_status = status;
93 break;
94 case BPRM_CHECK:
95 iint->ima_bprm_status = status;
96 break;
97 case FILE_CHECK:
98 case POST_SETATTR:
99 iint->ima_file_status = status;
100 break;
101 case MODULE_CHECK ... MAX_CHECK - 1:
102 default:
103 iint->ima_read_status = status;
104 break;
108 static void ima_cache_flags(struct integrity_iint_cache *iint,
109 enum ima_hooks func)
111 switch (func) {
112 case MMAP_CHECK:
113 iint->flags |= (IMA_MMAP_APPRAISED | IMA_APPRAISED);
114 break;
115 case BPRM_CHECK:
116 iint->flags |= (IMA_BPRM_APPRAISED | IMA_APPRAISED);
117 break;
118 case FILE_CHECK:
119 case POST_SETATTR:
120 iint->flags |= (IMA_FILE_APPRAISED | IMA_APPRAISED);
121 break;
122 case MODULE_CHECK ... MAX_CHECK - 1:
123 default:
124 iint->flags |= (IMA_READ_APPRAISED | IMA_APPRAISED);
125 break;
129 enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value,
130 int xattr_len)
132 struct signature_v2_hdr *sig;
133 enum hash_algo ret;
135 if (!xattr_value || xattr_len < 2)
136 /* return default hash algo */
137 return ima_hash_algo;
139 switch (xattr_value->type) {
140 case EVM_IMA_XATTR_DIGSIG:
141 sig = (typeof(sig))xattr_value;
142 if (sig->version != 2 || xattr_len <= sizeof(*sig))
143 return ima_hash_algo;
144 return sig->hash_algo;
145 break;
146 case IMA_XATTR_DIGEST_NG:
147 ret = xattr_value->digest[0];
148 if (ret < HASH_ALGO__LAST)
149 return ret;
150 break;
151 case IMA_XATTR_DIGEST:
152 /* this is for backward compatibility */
153 if (xattr_len == 21) {
154 unsigned int zero = 0;
155 if (!memcmp(&xattr_value->digest[16], &zero, 4))
156 return HASH_ALGO_MD5;
157 else
158 return HASH_ALGO_SHA1;
159 } else if (xattr_len == 17)
160 return HASH_ALGO_MD5;
161 break;
164 /* return default hash algo */
165 return ima_hash_algo;
168 int ima_read_xattr(struct dentry *dentry,
169 struct evm_ima_xattr_data **xattr_value)
171 ssize_t ret;
173 ret = vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)xattr_value,
174 0, GFP_NOFS);
175 if (ret == -EOPNOTSUPP)
176 ret = 0;
177 return ret;
181 * ima_appraise_measurement - appraise file measurement
183 * Call evm_verifyxattr() to verify the integrity of 'security.ima'.
184 * Assuming success, compare the xattr hash with the collected measurement.
186 * Return 0 on success, error code otherwise
188 int ima_appraise_measurement(enum ima_hooks func,
189 struct integrity_iint_cache *iint,
190 struct file *file, const unsigned char *filename,
191 struct evm_ima_xattr_data *xattr_value,
192 int xattr_len, int opened)
194 static const char op[] = "appraise_data";
195 char *cause = "unknown";
196 struct dentry *dentry = file_dentry(file);
197 struct inode *inode = d_backing_inode(dentry);
198 enum integrity_status status = INTEGRITY_UNKNOWN;
199 int rc = xattr_len, hash_start = 0;
201 if (!(inode->i_opflags & IOP_XATTR))
202 return INTEGRITY_UNKNOWN;
204 if (rc <= 0) {
205 if (rc && rc != -ENODATA)
206 goto out;
208 cause = "missing-hash";
209 status = INTEGRITY_NOLABEL;
210 if (opened & FILE_CREATED)
211 iint->flags |= IMA_NEW_FILE;
212 if ((iint->flags & IMA_NEW_FILE) &&
213 !(iint->flags & IMA_DIGSIG_REQUIRED))
214 status = INTEGRITY_PASS;
215 goto out;
218 status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint);
219 if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) {
220 if ((status == INTEGRITY_NOLABEL)
221 || (status == INTEGRITY_NOXATTRS))
222 cause = "missing-HMAC";
223 else if (status == INTEGRITY_FAIL)
224 cause = "invalid-HMAC";
225 goto out;
227 switch (xattr_value->type) {
228 case IMA_XATTR_DIGEST_NG:
229 /* first byte contains algorithm id */
230 hash_start = 1;
231 case IMA_XATTR_DIGEST:
232 if (iint->flags & IMA_DIGSIG_REQUIRED) {
233 cause = "IMA-signature-required";
234 status = INTEGRITY_FAIL;
235 break;
237 if (xattr_len - sizeof(xattr_value->type) - hash_start >=
238 iint->ima_hash->length)
239 /* xattr length may be longer. md5 hash in previous
240 version occupied 20 bytes in xattr, instead of 16
242 rc = memcmp(&xattr_value->digest[hash_start],
243 iint->ima_hash->digest,
244 iint->ima_hash->length);
245 else
246 rc = -EINVAL;
247 if (rc) {
248 cause = "invalid-hash";
249 status = INTEGRITY_FAIL;
250 break;
252 status = INTEGRITY_PASS;
253 break;
254 case EVM_IMA_XATTR_DIGSIG:
255 iint->flags |= IMA_DIGSIG;
256 rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
257 (const char *)xattr_value, rc,
258 iint->ima_hash->digest,
259 iint->ima_hash->length);
260 if (rc == -EOPNOTSUPP) {
261 status = INTEGRITY_UNKNOWN;
262 } else if (rc) {
263 cause = "invalid-signature";
264 status = INTEGRITY_FAIL;
265 } else {
266 status = INTEGRITY_PASS;
268 break;
269 default:
270 status = INTEGRITY_UNKNOWN;
271 cause = "unknown-ima-data";
272 break;
275 out:
276 if (status != INTEGRITY_PASS) {
277 if ((ima_appraise & IMA_APPRAISE_FIX) &&
278 (!xattr_value ||
279 xattr_value->type != EVM_IMA_XATTR_DIGSIG)) {
280 if (!ima_fix_xattr(dentry, iint))
281 status = INTEGRITY_PASS;
282 } else if ((inode->i_size == 0) &&
283 (iint->flags & IMA_NEW_FILE) &&
284 (xattr_value &&
285 xattr_value->type == EVM_IMA_XATTR_DIGSIG)) {
286 status = INTEGRITY_PASS;
288 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
289 op, cause, rc, 0);
290 } else {
291 ima_cache_flags(iint, func);
293 ima_set_cache_status(iint, func, status);
294 return status;
298 * ima_update_xattr - update 'security.ima' hash value
300 void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
302 struct dentry *dentry = file_dentry(file);
303 int rc = 0;
305 /* do not collect and update hash for digital signatures */
306 if (iint->flags & IMA_DIGSIG)
307 return;
309 rc = ima_collect_measurement(iint, file, NULL, 0, ima_hash_algo);
310 if (rc < 0)
311 return;
313 ima_fix_xattr(dentry, iint);
317 * ima_inode_post_setattr - reflect file metadata changes
318 * @dentry: pointer to the affected dentry
320 * Changes to a dentry's metadata might result in needing to appraise.
322 * This function is called from notify_change(), which expects the caller
323 * to lock the inode's i_mutex.
325 void ima_inode_post_setattr(struct dentry *dentry)
327 struct inode *inode = d_backing_inode(dentry);
328 struct integrity_iint_cache *iint;
329 int must_appraise;
331 if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode)
332 || !(inode->i_opflags & IOP_XATTR))
333 return;
335 must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR);
336 iint = integrity_iint_find(inode);
337 if (iint) {
338 iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
339 IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
340 IMA_ACTION_RULE_FLAGS);
341 if (must_appraise)
342 iint->flags |= IMA_APPRAISE;
344 if (!must_appraise)
345 __vfs_removexattr(dentry, XATTR_NAME_IMA);
349 * ima_protect_xattr - protect 'security.ima'
351 * Ensure that not just anyone can modify or remove 'security.ima'.
353 static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name,
354 const void *xattr_value, size_t xattr_value_len)
356 if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) {
357 if (!capable(CAP_SYS_ADMIN))
358 return -EPERM;
359 return 1;
361 return 0;
364 static void ima_reset_appraise_flags(struct inode *inode, int digsig)
366 struct integrity_iint_cache *iint;
368 if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode))
369 return;
371 iint = integrity_iint_find(inode);
372 if (!iint)
373 return;
375 iint->flags &= ~IMA_DONE_MASK;
376 iint->measured_pcrs = 0;
377 if (digsig)
378 iint->flags |= IMA_DIGSIG;
379 return;
382 int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
383 const void *xattr_value, size_t xattr_value_len)
385 const struct evm_ima_xattr_data *xvalue = xattr_value;
386 int result;
388 result = ima_protect_xattr(dentry, xattr_name, xattr_value,
389 xattr_value_len);
390 if (result == 1) {
391 if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST))
392 return -EINVAL;
393 ima_reset_appraise_flags(d_backing_inode(dentry),
394 (xvalue->type == EVM_IMA_XATTR_DIGSIG) ? 1 : 0);
395 result = 0;
397 return result;
400 int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name)
402 int result;
404 result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
405 if (result == 1) {
406 ima_reset_appraise_flags(d_backing_inode(dentry), 0);
407 result = 0;
409 return result;