Commit | Line | Data |
---|---|---|
bab73937 MZ |
1 | /* |
2 | * Copyright (C) 2005,2006,2007,2008 IBM Corporation | |
3 | * | |
4 | * Authors: | |
5 | * Kylene Hall <kjhall@us.ibm.com> | |
6 | * Reiner Sailer <sailer@us.ibm.com> | |
7 | * Mimi Zohar <zohar@us.ibm.com> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License as | |
11 | * published by the Free Software Foundation, version 2 of the | |
12 | * License. | |
13 | * | |
14 | * File: ima_fs.c | |
15 | * implemenents security file system for reporting | |
16 | * current measurement list and IMA statistics | |
17 | */ | |
f850a7c0 | 18 | #include <linux/fcntl.h> |
bab73937 MZ |
19 | #include <linux/module.h> |
20 | #include <linux/seq_file.h> | |
21 | #include <linux/rculist.h> | |
22 | #include <linux/rcupdate.h> | |
4af4662f | 23 | #include <linux/parser.h> |
bab73937 MZ |
24 | |
25 | #include "ima.h" | |
26 | ||
4af4662f | 27 | static int valid_policy = 1; |
bab73937 MZ |
28 | #define TMPBUFLEN 12 |
29 | static ssize_t ima_show_htable_value(char __user *buf, size_t count, | |
30 | loff_t *ppos, atomic_long_t *val) | |
31 | { | |
32 | char tmpbuf[TMPBUFLEN]; | |
33 | ssize_t len; | |
34 | ||
35 | len = scnprintf(tmpbuf, TMPBUFLEN, "%li\n", atomic_long_read(val)); | |
36 | return simple_read_from_buffer(buf, count, ppos, tmpbuf, len); | |
37 | } | |
38 | ||
39 | static ssize_t ima_show_htable_violations(struct file *filp, | |
40 | char __user *buf, | |
41 | size_t count, loff_t *ppos) | |
42 | { | |
43 | return ima_show_htable_value(buf, count, ppos, &ima_htable.violations); | |
44 | } | |
45 | ||
46 | static struct file_operations ima_htable_violations_ops = { | |
47 | .read = ima_show_htable_violations | |
48 | }; | |
49 | ||
50 | static ssize_t ima_show_measurements_count(struct file *filp, | |
51 | char __user *buf, | |
52 | size_t count, loff_t *ppos) | |
53 | { | |
54 | return ima_show_htable_value(buf, count, ppos, &ima_htable.len); | |
55 | ||
56 | } | |
57 | ||
58 | static struct file_operations ima_measurements_count_ops = { | |
59 | .read = ima_show_measurements_count | |
60 | }; | |
61 | ||
62 | /* returns pointer to hlist_node */ | |
63 | static void *ima_measurements_start(struct seq_file *m, loff_t *pos) | |
64 | { | |
65 | loff_t l = *pos; | |
66 | struct ima_queue_entry *qe; | |
67 | ||
68 | /* we need a lock since pos could point beyond last element */ | |
69 | rcu_read_lock(); | |
70 | list_for_each_entry_rcu(qe, &ima_measurements, later) { | |
71 | if (!l--) { | |
72 | rcu_read_unlock(); | |
73 | return qe; | |
74 | } | |
75 | } | |
76 | rcu_read_unlock(); | |
77 | return NULL; | |
78 | } | |
79 | ||
80 | static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos) | |
81 | { | |
82 | struct ima_queue_entry *qe = v; | |
83 | ||
84 | /* lock protects when reading beyond last element | |
85 | * against concurrent list-extension | |
86 | */ | |
87 | rcu_read_lock(); | |
88 | qe = list_entry(rcu_dereference(qe->later.next), | |
89 | struct ima_queue_entry, later); | |
90 | rcu_read_unlock(); | |
91 | (*pos)++; | |
92 | ||
93 | return (&qe->later == &ima_measurements) ? NULL : qe; | |
94 | } | |
95 | ||
96 | static void ima_measurements_stop(struct seq_file *m, void *v) | |
97 | { | |
98 | } | |
99 | ||
100 | static void ima_putc(struct seq_file *m, void *data, int datalen) | |
101 | { | |
102 | while (datalen--) | |
103 | seq_putc(m, *(char *)data++); | |
104 | } | |
105 | ||
106 | /* print format: | |
107 | * 32bit-le=pcr# | |
108 | * char[20]=template digest | |
109 | * 32bit-le=template name size | |
110 | * char[n]=template name | |
111 | * eventdata[n]=template specific data | |
112 | */ | |
113 | static int ima_measurements_show(struct seq_file *m, void *v) | |
114 | { | |
115 | /* the list never shrinks, so we don't need a lock here */ | |
116 | struct ima_queue_entry *qe = v; | |
117 | struct ima_template_entry *e; | |
118 | int namelen; | |
119 | u32 pcr = CONFIG_IMA_MEASURE_PCR_IDX; | |
120 | ||
121 | /* get entry */ | |
122 | e = qe->entry; | |
123 | if (e == NULL) | |
124 | return -1; | |
125 | ||
126 | /* | |
127 | * 1st: PCRIndex | |
128 | * PCR used is always the same (config option) in | |
129 | * little-endian format | |
130 | */ | |
131 | ima_putc(m, &pcr, sizeof pcr); | |
132 | ||
133 | /* 2nd: template digest */ | |
134 | ima_putc(m, e->digest, IMA_DIGEST_SIZE); | |
135 | ||
136 | /* 3rd: template name size */ | |
137 | namelen = strlen(e->template_name); | |
138 | ima_putc(m, &namelen, sizeof namelen); | |
139 | ||
140 | /* 4th: template name */ | |
523979ad | 141 | ima_putc(m, (void *)e->template_name, namelen); |
bab73937 MZ |
142 | |
143 | /* 5th: template specific data */ | |
144 | ima_template_show(m, (struct ima_template_data *)&e->template, | |
145 | IMA_SHOW_BINARY); | |
146 | return 0; | |
147 | } | |
148 | ||
149 | static struct seq_operations ima_measurments_seqops = { | |
150 | .start = ima_measurements_start, | |
151 | .next = ima_measurements_next, | |
152 | .stop = ima_measurements_stop, | |
153 | .show = ima_measurements_show | |
154 | }; | |
155 | ||
156 | static int ima_measurements_open(struct inode *inode, struct file *file) | |
157 | { | |
158 | return seq_open(file, &ima_measurments_seqops); | |
159 | } | |
160 | ||
161 | static struct file_operations ima_measurements_ops = { | |
162 | .open = ima_measurements_open, | |
163 | .read = seq_read, | |
164 | .llseek = seq_lseek, | |
165 | .release = seq_release, | |
166 | }; | |
167 | ||
168 | static void ima_print_digest(struct seq_file *m, u8 *digest) | |
169 | { | |
170 | int i; | |
171 | ||
172 | for (i = 0; i < IMA_DIGEST_SIZE; i++) | |
173 | seq_printf(m, "%02x", *(digest + i)); | |
174 | } | |
175 | ||
176 | void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show) | |
177 | { | |
178 | struct ima_template_data *entry = e; | |
179 | int namelen; | |
180 | ||
181 | switch (show) { | |
182 | case IMA_SHOW_ASCII: | |
183 | ima_print_digest(m, entry->digest); | |
184 | seq_printf(m, " %s\n", entry->file_name); | |
185 | break; | |
186 | case IMA_SHOW_BINARY: | |
187 | ima_putc(m, entry->digest, IMA_DIGEST_SIZE); | |
188 | ||
189 | namelen = strlen(entry->file_name); | |
190 | ima_putc(m, &namelen, sizeof namelen); | |
191 | ima_putc(m, entry->file_name, namelen); | |
192 | default: | |
193 | break; | |
194 | } | |
195 | } | |
196 | ||
197 | /* print in ascii */ | |
198 | static int ima_ascii_measurements_show(struct seq_file *m, void *v) | |
199 | { | |
200 | /* the list never shrinks, so we don't need a lock here */ | |
201 | struct ima_queue_entry *qe = v; | |
202 | struct ima_template_entry *e; | |
203 | ||
204 | /* get entry */ | |
205 | e = qe->entry; | |
206 | if (e == NULL) | |
207 | return -1; | |
208 | ||
209 | /* 1st: PCR used (config option) */ | |
210 | seq_printf(m, "%2d ", CONFIG_IMA_MEASURE_PCR_IDX); | |
211 | ||
212 | /* 2nd: SHA1 template hash */ | |
213 | ima_print_digest(m, e->digest); | |
214 | ||
215 | /* 3th: template name */ | |
216 | seq_printf(m, " %s ", e->template_name); | |
217 | ||
218 | /* 4th: template specific data */ | |
219 | ima_template_show(m, (struct ima_template_data *)&e->template, | |
220 | IMA_SHOW_ASCII); | |
221 | return 0; | |
222 | } | |
223 | ||
224 | static struct seq_operations ima_ascii_measurements_seqops = { | |
225 | .start = ima_measurements_start, | |
226 | .next = ima_measurements_next, | |
227 | .stop = ima_measurements_stop, | |
228 | .show = ima_ascii_measurements_show | |
229 | }; | |
230 | ||
231 | static int ima_ascii_measurements_open(struct inode *inode, struct file *file) | |
232 | { | |
233 | return seq_open(file, &ima_ascii_measurements_seqops); | |
234 | } | |
235 | ||
236 | static struct file_operations ima_ascii_measurements_ops = { | |
237 | .open = ima_ascii_measurements_open, | |
238 | .read = seq_read, | |
239 | .llseek = seq_lseek, | |
240 | .release = seq_release, | |
241 | }; | |
242 | ||
4af4662f MZ |
243 | static ssize_t ima_write_policy(struct file *file, const char __user *buf, |
244 | size_t datalen, loff_t *ppos) | |
245 | { | |
246 | char *data; | |
247 | int rc; | |
248 | ||
249 | if (datalen >= PAGE_SIZE) | |
250 | return -ENOMEM; | |
251 | if (*ppos != 0) { | |
252 | /* No partial writes. */ | |
253 | return -EINVAL; | |
254 | } | |
255 | data = kmalloc(datalen + 1, GFP_KERNEL); | |
256 | if (!data) | |
257 | return -ENOMEM; | |
258 | ||
259 | if (copy_from_user(data, buf, datalen)) { | |
260 | kfree(data); | |
261 | return -EFAULT; | |
262 | } | |
263 | *(data + datalen) = '\0'; | |
264 | rc = ima_parse_add_rule(data); | |
265 | if (rc < 0) { | |
266 | datalen = -EINVAL; | |
267 | valid_policy = 0; | |
268 | } | |
269 | ||
270 | kfree(data); | |
271 | return datalen; | |
272 | } | |
273 | ||
bab73937 MZ |
274 | static struct dentry *ima_dir; |
275 | static struct dentry *binary_runtime_measurements; | |
276 | static struct dentry *ascii_runtime_measurements; | |
277 | static struct dentry *runtime_measurements_count; | |
278 | static struct dentry *violations; | |
4af4662f MZ |
279 | static struct dentry *ima_policy; |
280 | ||
f4bd857b MZ |
281 | static atomic_t policy_opencount = ATOMIC_INIT(1); |
282 | /* | |
283 | * ima_open_policy: sequentialize access to the policy file | |
284 | */ | |
285 | int ima_open_policy(struct inode * inode, struct file * filp) | |
286 | { | |
f850a7c0 EP |
287 | /* No point in being allowed to open it if you aren't going to write */ |
288 | if (!(filp->f_flags & O_WRONLY)) | |
289 | return -EACCES; | |
f4bd857b MZ |
290 | if (atomic_dec_and_test(&policy_opencount)) |
291 | return 0; | |
292 | return -EBUSY; | |
293 | } | |
294 | ||
4af4662f MZ |
295 | /* |
296 | * ima_release_policy - start using the new measure policy rules. | |
297 | * | |
298 | * Initially, ima_measure points to the default policy rules, now | |
f4bd857b MZ |
299 | * point to the new policy rules, and remove the securityfs policy file, |
300 | * assuming a valid policy. | |
4af4662f MZ |
301 | */ |
302 | static int ima_release_policy(struct inode *inode, struct file *file) | |
303 | { | |
304 | if (!valid_policy) { | |
305 | ima_delete_rules(); | |
f4bd857b MZ |
306 | valid_policy = 1; |
307 | atomic_set(&policy_opencount, 1); | |
4af4662f MZ |
308 | return 0; |
309 | } | |
310 | ima_update_policy(); | |
311 | securityfs_remove(ima_policy); | |
312 | ima_policy = NULL; | |
313 | return 0; | |
314 | } | |
315 | ||
316 | static struct file_operations ima_measure_policy_ops = { | |
f4bd857b | 317 | .open = ima_open_policy, |
4af4662f MZ |
318 | .write = ima_write_policy, |
319 | .release = ima_release_policy | |
320 | }; | |
bab73937 MZ |
321 | |
322 | int ima_fs_init(void) | |
323 | { | |
324 | ima_dir = securityfs_create_dir("ima", NULL); | |
325 | if (IS_ERR(ima_dir)) | |
326 | return -1; | |
327 | ||
328 | binary_runtime_measurements = | |
329 | securityfs_create_file("binary_runtime_measurements", | |
330 | S_IRUSR | S_IRGRP, ima_dir, NULL, | |
331 | &ima_measurements_ops); | |
332 | if (IS_ERR(binary_runtime_measurements)) | |
333 | goto out; | |
334 | ||
335 | ascii_runtime_measurements = | |
336 | securityfs_create_file("ascii_runtime_measurements", | |
337 | S_IRUSR | S_IRGRP, ima_dir, NULL, | |
338 | &ima_ascii_measurements_ops); | |
339 | if (IS_ERR(ascii_runtime_measurements)) | |
340 | goto out; | |
341 | ||
342 | runtime_measurements_count = | |
343 | securityfs_create_file("runtime_measurements_count", | |
344 | S_IRUSR | S_IRGRP, ima_dir, NULL, | |
345 | &ima_measurements_count_ops); | |
346 | if (IS_ERR(runtime_measurements_count)) | |
347 | goto out; | |
348 | ||
349 | violations = | |
350 | securityfs_create_file("violations", S_IRUSR | S_IRGRP, | |
351 | ima_dir, NULL, &ima_htable_violations_ops); | |
352 | if (IS_ERR(violations)) | |
353 | goto out; | |
354 | ||
4af4662f | 355 | ima_policy = securityfs_create_file("policy", |
f850a7c0 | 356 | S_IWUSR, |
4af4662f MZ |
357 | ima_dir, NULL, |
358 | &ima_measure_policy_ops); | |
359 | if (IS_ERR(ima_policy)) | |
360 | goto out; | |
bab73937 | 361 | |
4af4662f | 362 | return 0; |
bab73937 MZ |
363 | out: |
364 | securityfs_remove(runtime_measurements_count); | |
365 | securityfs_remove(ascii_runtime_measurements); | |
366 | securityfs_remove(binary_runtime_measurements); | |
367 | securityfs_remove(ima_dir); | |
4af4662f | 368 | securityfs_remove(ima_policy); |
bab73937 MZ |
369 | return -1; |
370 | } | |
371 | ||
372 | void __exit ima_fs_cleanup(void) | |
373 | { | |
374 | securityfs_remove(violations); | |
375 | securityfs_remove(runtime_measurements_count); | |
376 | securityfs_remove(ascii_runtime_measurements); | |
377 | securityfs_remove(binary_runtime_measurements); | |
378 | securityfs_remove(ima_dir); | |
4af4662f | 379 | securityfs_remove(ima_policy); |
bab73937 | 380 | } |