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authorMimi Zohar <zohar@linux.vnet.ibm.com>2009-02-04 09:07:00 -0500
committerJames Morris <jmorris@namei.org>2009-02-05 17:05:31 -0500
commit4af4662fa4a9dc62289c580337ae2506339c4729 (patch)
treefaec95258d2456eb35515f289eb688914ce3b54f /security
parentbab739378758a1e2b2d7ddcee7bc06cf4c591c3c (diff)
integrity: IMA policy
Support for a user loadable policy through securityfs with support for LSM specific policy data. - free invalid rule in ima_parse_add_rule() Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/ima/Kconfig6
-rw-r--r--security/integrity/ima/ima.h24
-rw-r--r--security/integrity/ima/ima_fs.c67
-rw-r--r--security/integrity/ima/ima_policy.c293
4 files changed, 386 insertions, 4 deletions
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 2a761c8ac996..3d2b6ee778a0 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -47,3 +47,9 @@ config IMA_AUDIT
47 auditing messages can be enabled with 'ima_audit=1' on 47 auditing messages can be enabled with 'ima_audit=1' on
48 the kernel command line. 48 the kernel command line.
49 49
50config IMA_LSM_RULES
51 bool
52 depends on IMA && (SECURITY_SELINUX || SECURITY_SMACK)
53 default y
54 help
55 Disabling this option will disregard LSM based policy rules
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 9c280cc73004..42706b554921 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -137,4 +137,28 @@ enum ima_hooks { PATH_CHECK = 1, FILE_MMAP, BPRM_CHECK };
137int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask); 137int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask);
138void ima_init_policy(void); 138void ima_init_policy(void);
139void ima_update_policy(void); 139void ima_update_policy(void);
140int ima_parse_add_rule(char *);
141void ima_delete_rules(void);
142
143/* LSM based policy rules require audit */
144#ifdef CONFIG_IMA_LSM_RULES
145
146#define security_filter_rule_init security_audit_rule_init
147#define security_filter_rule_match security_audit_rule_match
148
149#else
150
151static inline int security_filter_rule_init(u32 field, u32 op, char *rulestr,
152 void **lsmrule)
153{
154 return -EINVAL;
155}
156
157static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
158 void *lsmrule,
159 struct audit_context *actx)
160{
161 return -EINVAL;
162}
163#endif /* CONFIG_IMA_LSM_RULES */
140#endif 164#endif
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 4f25be768b50..95ef1caa64b5 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -19,9 +19,11 @@
19#include <linux/seq_file.h> 19#include <linux/seq_file.h>
20#include <linux/rculist.h> 20#include <linux/rculist.h>
21#include <linux/rcupdate.h> 21#include <linux/rcupdate.h>
22#include <linux/parser.h>
22 23
23#include "ima.h" 24#include "ima.h"
24 25
26static int valid_policy = 1;
25#define TMPBUFLEN 12 27#define TMPBUFLEN 12
26static ssize_t ima_show_htable_value(char __user *buf, size_t count, 28static ssize_t ima_show_htable_value(char __user *buf, size_t count,
27 loff_t *ppos, atomic_long_t *val) 29 loff_t *ppos, atomic_long_t *val)
@@ -237,11 +239,66 @@ static struct file_operations ima_ascii_measurements_ops = {
237 .release = seq_release, 239 .release = seq_release,
238}; 240};
239 241
242static ssize_t ima_write_policy(struct file *file, const char __user *buf,
243 size_t datalen, loff_t *ppos)
244{
245 char *data;
246 int rc;
247
248 if (datalen >= PAGE_SIZE)
249 return -ENOMEM;
250 if (*ppos != 0) {
251 /* No partial writes. */
252 return -EINVAL;
253 }
254 data = kmalloc(datalen + 1, GFP_KERNEL);
255 if (!data)
256 return -ENOMEM;
257
258 if (copy_from_user(data, buf, datalen)) {
259 kfree(data);
260 return -EFAULT;
261 }
262 *(data + datalen) = '\0';
263 rc = ima_parse_add_rule(data);
264 if (rc < 0) {
265 datalen = -EINVAL;
266 valid_policy = 0;
267 }
268
269 kfree(data);
270 return datalen;
271}
272
240static struct dentry *ima_dir; 273static struct dentry *ima_dir;
241static struct dentry *binary_runtime_measurements; 274static struct dentry *binary_runtime_measurements;
242static struct dentry *ascii_runtime_measurements; 275static struct dentry *ascii_runtime_measurements;
243static struct dentry *runtime_measurements_count; 276static struct dentry *runtime_measurements_count;
244static struct dentry *violations; 277static struct dentry *violations;
278static struct dentry *ima_policy;
279
280/*
281 * ima_release_policy - start using the new measure policy rules.
282 *
283 * Initially, ima_measure points to the default policy rules, now
284 * point to the new policy rules, and remove the securityfs policy file.
285 */
286static int ima_release_policy(struct inode *inode, struct file *file)
287{
288 if (!valid_policy) {
289 ima_delete_rules();
290 return 0;
291 }
292 ima_update_policy();
293 securityfs_remove(ima_policy);
294 ima_policy = NULL;
295 return 0;
296}
297
298static struct file_operations ima_measure_policy_ops = {
299 .write = ima_write_policy,
300 .release = ima_release_policy
301};
245 302
246int ima_fs_init(void) 303int ima_fs_init(void)
247{ 304{
@@ -276,13 +333,20 @@ int ima_fs_init(void)
276 if (IS_ERR(violations)) 333 if (IS_ERR(violations))
277 goto out; 334 goto out;
278 335
279 return 0; 336 ima_policy = securityfs_create_file("policy",
337 S_IRUSR | S_IRGRP | S_IWUSR,
338 ima_dir, NULL,
339 &ima_measure_policy_ops);
340 if (IS_ERR(ima_policy))
341 goto out;
280 342
343 return 0;
281out: 344out:
282 securityfs_remove(runtime_measurements_count); 345 securityfs_remove(runtime_measurements_count);
283 securityfs_remove(ascii_runtime_measurements); 346 securityfs_remove(ascii_runtime_measurements);
284 securityfs_remove(binary_runtime_measurements); 347 securityfs_remove(binary_runtime_measurements);
285 securityfs_remove(ima_dir); 348 securityfs_remove(ima_dir);
349 securityfs_remove(ima_policy);
286 return -1; 350 return -1;
287} 351}
288 352
@@ -293,4 +357,5 @@ void __exit ima_fs_cleanup(void)
293 securityfs_remove(ascii_runtime_measurements); 357 securityfs_remove(ascii_runtime_measurements);
294 securityfs_remove(binary_runtime_measurements); 358 securityfs_remove(binary_runtime_measurements);
295 securityfs_remove(ima_dir); 359 securityfs_remove(ima_dir);
360 securityfs_remove(ima_policy);
296} 361}
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 7c3d1ffb1472..bd453603e2c3 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -15,6 +15,7 @@
15#include <linux/audit.h> 15#include <linux/audit.h>
16#include <linux/security.h> 16#include <linux/security.h>
17#include <linux/magic.h> 17#include <linux/magic.h>
18#include <linux/parser.h>
18 19
19#include "ima.h" 20#include "ima.h"
20 21
@@ -24,7 +25,12 @@
24#define IMA_FSMAGIC 0x0004 25#define IMA_FSMAGIC 0x0004
25#define IMA_UID 0x0008 26#define IMA_UID 0x0008
26 27
27enum ima_action { DONT_MEASURE, MEASURE }; 28enum ima_action { UNKNOWN = -1, DONT_MEASURE = 0, MEASURE };
29
30#define MAX_LSM_RULES 6
31enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
32 LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
33};
28 34
29struct ima_measure_rule_entry { 35struct ima_measure_rule_entry {
30 struct list_head list; 36 struct list_head list;
@@ -34,8 +40,15 @@ struct ima_measure_rule_entry {
34 int mask; 40 int mask;
35 unsigned long fsmagic; 41 unsigned long fsmagic;
36 uid_t uid; 42 uid_t uid;
43 struct {
44 void *rule; /* LSM file metadata specific */
45 int type; /* audit type */
46 } lsm[MAX_LSM_RULES];
37}; 47};
38 48
49/* Without LSM specific knowledge, the default policy can only be
50 * written in terms of .action, .func, .mask, .fsmagic, and .uid
51 */
39static struct ima_measure_rule_entry default_rules[] = { 52static struct ima_measure_rule_entry default_rules[] = {
40 {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC, 53 {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,
41 .flags = IMA_FSMAGIC}, 54 .flags = IMA_FSMAGIC},
@@ -54,8 +67,11 @@ static struct ima_measure_rule_entry default_rules[] = {
54}; 67};
55 68
56static LIST_HEAD(measure_default_rules); 69static LIST_HEAD(measure_default_rules);
70static LIST_HEAD(measure_policy_rules);
57static struct list_head *ima_measure; 71static struct list_head *ima_measure;
58 72
73static DEFINE_MUTEX(ima_measure_mutex);
74
59/** 75/**
60 * ima_match_rules - determine whether an inode matches the measure rule. 76 * ima_match_rules - determine whether an inode matches the measure rule.
61 * @rule: a pointer to a rule 77 * @rule: a pointer to a rule
@@ -69,6 +85,7 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule,
69 struct inode *inode, enum ima_hooks func, int mask) 85 struct inode *inode, enum ima_hooks func, int mask)
70{ 86{
71 struct task_struct *tsk = current; 87 struct task_struct *tsk = current;
88 int i;
72 89
73 if ((rule->flags & IMA_FUNC) && rule->func != func) 90 if ((rule->flags & IMA_FUNC) && rule->func != func)
74 return false; 91 return false;
@@ -79,6 +96,39 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule,
79 return false; 96 return false;
80 if ((rule->flags & IMA_UID) && rule->uid != tsk->cred->uid) 97 if ((rule->flags & IMA_UID) && rule->uid != tsk->cred->uid)
81 return false; 98 return false;
99 for (i = 0; i < MAX_LSM_RULES; i++) {
100 int rc;
101 u32 osid, sid;
102
103 if (!rule->lsm[i].rule)
104 continue;
105
106 switch (i) {
107 case LSM_OBJ_USER:
108 case LSM_OBJ_ROLE:
109 case LSM_OBJ_TYPE:
110 security_inode_getsecid(inode, &osid);
111 rc = security_filter_rule_match(osid,
112 rule->lsm[i].type,
113 AUDIT_EQUAL,
114 rule->lsm[i].rule,
115 NULL);
116 break;
117 case LSM_SUBJ_USER:
118 case LSM_SUBJ_ROLE:
119 case LSM_SUBJ_TYPE:
120 security_task_getsecid(tsk, &sid);
121 rc = security_filter_rule_match(sid,
122 rule->lsm[i].type,
123 AUDIT_EQUAL,
124 rule->lsm[i].rule,
125 NULL);
126 default:
127 break;
128 }
129 if (!rc)
130 return false;
131 }
82 return true; 132 return true;
83} 133}
84 134
@@ -112,9 +162,8 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask)
112/** 162/**
113 * ima_init_policy - initialize the default measure rules. 163 * ima_init_policy - initialize the default measure rules.
114 * 164 *
115 * (Could use the default_rules directly, but in policy patch
116 * ima_measure points to either the measure_default_rules or the 165 * ima_measure points to either the measure_default_rules or the
117 * the new measure_policy_rules.) 166 * the new measure_policy_rules.
118 */ 167 */
119void ima_init_policy(void) 168void ima_init_policy(void)
120{ 169{
@@ -124,3 +173,241 @@ void ima_init_policy(void)
124 list_add_tail(&default_rules[i].list, &measure_default_rules); 173 list_add_tail(&default_rules[i].list, &measure_default_rules);
125 ima_measure = &measure_default_rules; 174 ima_measure = &measure_default_rules;
126} 175}
176
177/**
178 * ima_update_policy - update default_rules with new measure rules
179 *
180 * Called on file .release to update the default rules with a complete new
181 * policy. Once updated, the policy is locked, no additional rules can be
182 * added to the policy.
183 */
184void ima_update_policy(void)
185{
186 const char *op = "policy_update";
187 const char *cause = "already exists";
188 int result = 1;
189 int audit_info = 0;
190
191 if (ima_measure == &measure_default_rules) {
192 ima_measure = &measure_policy_rules;
193 cause = "complete";
194 result = 0;
195 }
196 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
197 NULL, op, cause, result, audit_info);
198}
199
200enum {
201 Opt_err = -1,
202 Opt_measure = 1, Opt_dont_measure,
203 Opt_obj_user, Opt_obj_role, Opt_obj_type,
204 Opt_subj_user, Opt_subj_role, Opt_subj_type,
205 Opt_func, Opt_mask, Opt_fsmagic, Opt_uid
206};
207
208static match_table_t policy_tokens = {
209 {Opt_measure, "measure"},
210 {Opt_dont_measure, "dont_measure"},
211 {Opt_obj_user, "obj_user=%s"},
212 {Opt_obj_role, "obj_role=%s"},
213 {Opt_obj_type, "obj_type=%s"},
214 {Opt_subj_user, "subj_user=%s"},
215 {Opt_subj_role, "subj_role=%s"},
216 {Opt_subj_type, "subj_type=%s"},
217 {Opt_func, "func=%s"},
218 {Opt_mask, "mask=%s"},
219 {Opt_fsmagic, "fsmagic=%s"},
220 {Opt_uid, "uid=%s"},
221 {Opt_err, NULL}
222};
223
224static int ima_lsm_rule_init(struct ima_measure_rule_entry *entry,
225 char *args, int lsm_rule, int audit_type)
226{
227 int result;
228
229 entry->lsm[lsm_rule].type = audit_type;
230 result = security_filter_rule_init(entry->lsm[lsm_rule].type,
231 AUDIT_EQUAL, args,
232 &entry->lsm[lsm_rule].rule);
233 return result;
234}
235
236static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry)
237{
238 struct audit_buffer *ab;
239 char *p;
240 int result = 0;
241
242 ab = audit_log_start(current->audit_context, GFP_KERNEL,
243 AUDIT_INTEGRITY_STATUS);
244
245 entry->action = -1;
246 while ((p = strsep(&rule, " \n")) != NULL) {
247 substring_t args[MAX_OPT_ARGS];
248 int token;
249 unsigned long lnum;
250
251 if (result < 0)
252 break;
253 if (!*p)
254 continue;
255 token = match_token(p, policy_tokens, args);
256 switch (token) {
257 case Opt_measure:
258 audit_log_format(ab, "%s ", "measure");
259 entry->action = MEASURE;
260 break;
261 case Opt_dont_measure:
262 audit_log_format(ab, "%s ", "dont_measure");
263 entry->action = DONT_MEASURE;
264 break;
265 case Opt_func:
266 audit_log_format(ab, "func=%s ", args[0].from);
267 if (strcmp(args[0].from, "PATH_CHECK") == 0)
268 entry->func = PATH_CHECK;
269 else if (strcmp(args[0].from, "FILE_MMAP") == 0)
270 entry->func = FILE_MMAP;
271 else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
272 entry->func = BPRM_CHECK;
273 else
274 result = -EINVAL;
275 if (!result)
276 entry->flags |= IMA_FUNC;
277 break;
278 case Opt_mask:
279 audit_log_format(ab, "mask=%s ", args[0].from);
280 if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
281 entry->mask = MAY_EXEC;
282 else if (strcmp(args[0].from, "MAY_WRITE") == 0)
283 entry->mask = MAY_WRITE;
284 else if (strcmp(args[0].from, "MAY_READ") == 0)
285 entry->mask = MAY_READ;
286 else if (strcmp(args[0].from, "MAY_APPEND") == 0)
287 entry->mask = MAY_APPEND;
288 else
289 result = -EINVAL;
290 if (!result)
291 entry->flags |= IMA_MASK;
292 break;
293 case Opt_fsmagic:
294 audit_log_format(ab, "fsmagic=%s ", args[0].from);
295 result = strict_strtoul(args[0].from, 16,
296 &entry->fsmagic);
297 if (!result)
298 entry->flags |= IMA_FSMAGIC;
299 break;
300 case Opt_uid:
301 audit_log_format(ab, "uid=%s ", args[0].from);
302 result = strict_strtoul(args[0].from, 10, &lnum);
303 if (!result) {
304 entry->uid = (uid_t) lnum;
305 if (entry->uid != lnum)
306 result = -EINVAL;
307 else
308 entry->flags |= IMA_UID;
309 }
310 break;
311 case Opt_obj_user:
312 audit_log_format(ab, "obj_user=%s ", args[0].from);
313 result = ima_lsm_rule_init(entry, args[0].from,
314 LSM_OBJ_USER,
315 AUDIT_OBJ_USER);
316 break;
317 case Opt_obj_role:
318 audit_log_format(ab, "obj_role=%s ", args[0].from);
319 result = ima_lsm_rule_init(entry, args[0].from,
320 LSM_OBJ_ROLE,
321 AUDIT_OBJ_ROLE);
322 break;
323 case Opt_obj_type:
324 audit_log_format(ab, "obj_type=%s ", args[0].from);
325 result = ima_lsm_rule_init(entry, args[0].from,
326 LSM_OBJ_TYPE,
327 AUDIT_OBJ_TYPE);
328 break;
329 case Opt_subj_user:
330 audit_log_format(ab, "subj_user=%s ", args[0].from);
331 result = ima_lsm_rule_init(entry, args[0].from,
332 LSM_SUBJ_USER,
333 AUDIT_SUBJ_USER);
334 break;
335 case Opt_subj_role:
336 audit_log_format(ab, "subj_role=%s ", args[0].from);
337 result = ima_lsm_rule_init(entry, args[0].from,
338 LSM_SUBJ_ROLE,
339 AUDIT_SUBJ_ROLE);
340 break;
341 case Opt_subj_type:
342 audit_log_format(ab, "subj_type=%s ", args[0].from);
343 result = ima_lsm_rule_init(entry, args[0].from,
344 LSM_SUBJ_TYPE,
345 AUDIT_SUBJ_TYPE);
346 break;
347 case Opt_err:
348 printk(KERN_INFO "%s: unknown token: %s\n",
349 __FUNCTION__, p);
350 break;
351 }
352 }
353 if (entry->action == UNKNOWN)
354 result = -EINVAL;
355
356 audit_log_format(ab, "res=%d", result);
357 audit_log_end(ab);
358 return result;
359}
360
361/**
362 * ima_parse_add_rule - add a rule to measure_policy_rules
363 * @rule - ima measurement policy rule
364 *
365 * Uses a mutex to protect the policy list from multiple concurrent writers.
366 * Returns 0 on success, an error code on failure.
367 */
368int ima_parse_add_rule(char *rule)
369{
370 const char *op = "add_rule";
371 struct ima_measure_rule_entry *entry;
372 int result = 0;
373 int audit_info = 0;
374
375 /* Prevent installed policy from changing */
376 if (ima_measure != &measure_default_rules) {
377 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
378 NULL, op, "already exists",
379 -EACCES, audit_info);
380 return -EACCES;
381 }
382
383 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
384 if (!entry) {
385 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
386 NULL, op, "-ENOMEM", -ENOMEM, audit_info);
387 return -ENOMEM;
388 }
389
390 INIT_LIST_HEAD(&entry->list);
391
392 result = ima_parse_rule(rule, entry);
393 if (!result) {
394 mutex_lock(&ima_measure_mutex);
395 list_add_tail(&entry->list, &measure_policy_rules);
396 mutex_unlock(&ima_measure_mutex);
397 } else
398 kfree(entry);
399 return result;
400}
401
402/* ima_delete_rules called to cleanup invalid policy */
403void ima_delete_rules()
404{
405 struct ima_measure_rule_entry *entry, *tmp;
406
407 mutex_lock(&ima_measure_mutex);
408 list_for_each_entry_safe(entry, tmp, &measure_policy_rules, list) {
409 list_del(&entry->list);
410 kfree(entry);
411 }
412 mutex_unlock(&ima_measure_mutex);
413}