2 * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, version 2.
9 * Casey Schaufler <casey@schaufler-ca.com>
13 #include <linux/types.h>
14 #include <linux/slab.h>
16 #include <linux/sched.h>
19 struct smack_known smack_known_huh = {
24 struct smack_known smack_known_hat = {
29 struct smack_known smack_known_star = {
34 struct smack_known smack_known_floor = {
39 struct smack_known smack_known_invalid = {
44 struct smack_known smack_known_web = {
49 LIST_HEAD(smack_known_list);
52 * The initial value needs to be bigger than any of the
55 static u32 smack_next_secid = 10;
58 * what events do we log
59 * can be overwritten at run-time by /smack/logging
61 int log_policy = SMACK_AUDIT_DENIED;
64 * smk_access_entry - look up matching access rule
65 * @subject_label: a pointer to the subject's Smack label
66 * @object_label: a pointer to the object's Smack label
67 * @rule_list: the list of rules to search
69 * This function looks up the subject/object pair in the
70 * access rule list and returns the access mode. If no
71 * entry is found returns -ENOENT.
75 * Earlier versions of this function allowed for labels that
76 * were not on the label list. This was done to allow for
77 * labels to come over the network that had never been seen
78 * before on this host. Unless the receiving socket has the
79 * star label this will always result in a failure check. The
80 * star labeled socket case is now handled in the networking
81 * hooks so there is no case where the label is not on the
82 * label list. Checking to see if the address of two labels
83 * is the same is now a reliable test.
85 * Do the object check first because that is more
88 * Allowing write access implies allowing locking.
90 int smk_access_entry(char *subject_label, char *object_label,
91 struct list_head *rule_list)
93 struct smack_rule *srp;
95 list_for_each_entry_rcu(srp, rule_list, list) {
96 if (srp->smk_object->smk_known == object_label &&
97 srp->smk_subject->smk_known == subject_label) {
98 int may = srp->smk_access;
100 * MAY_WRITE implies MAY_LOCK.
102 if ((may & MAY_WRITE) == MAY_WRITE)
112 * smk_access - determine if a subject has a specific access to an object
113 * @subject: a pointer to the subject's Smack label entry
114 * @object: a pointer to the object's Smack label entry
115 * @request: the access requested, in "MAY" format
116 * @a : a pointer to the audit data
118 * This function looks up the subject/object pair in the
119 * access rule list and returns 0 if the access is permitted,
120 * non zero otherwise.
122 * Smack labels are shared on smack_list
124 int smk_access(struct smack_known *subject, struct smack_known *object,
125 int request, struct smk_audit_info *a)
131 * Hardcoded comparisons.
134 * A star subject can't access any object.
136 if (subject == &smack_known_star) {
141 * An internet object can be accessed by any subject.
142 * Tasks cannot be assigned the internet label.
143 * An internet subject can access any object.
145 if (object == &smack_known_web || subject == &smack_known_web)
148 * A star object can be accessed by any subject.
150 if (object == &smack_known_star)
153 * An object can be accessed in any way by a subject
154 * with the same label.
156 if (subject->smk_known == object->smk_known)
159 * A hat subject can read or lock any object.
160 * A floor object can be read or locked by any subject.
162 if ((request & MAY_ANYREAD) == request ||
163 (request & MAY_LOCK) == request) {
164 if (object == &smack_known_floor)
166 if (subject == &smack_known_hat)
170 * Beyond here an explicit relationship is required.
171 * If the requested access is contained in the available
172 * access (e.g. read is included in readwrite) it's
173 * good. A negative response from smk_access_entry()
174 * indicates there is no entry for this pair.
177 may = smk_access_entry(subject->smk_known, object->smk_known,
178 &subject->smk_rules);
181 if (may <= 0 || (request & may) != request) {
185 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
187 * Return a positive value if using bringup mode.
188 * This allows the hooks to identify checks that
189 * succeed because of "b" rules.
191 if (may & MAY_BRINGUP)
192 rc = SMACK_BRINGUP_ALLOW;
197 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
199 if (object == smack_unconfined)
200 rc = SMACK_UNCONFINED_OBJECT;
201 if (subject == smack_unconfined)
202 rc = SMACK_UNCONFINED_SUBJECT;
208 smack_log(subject->smk_known, object->smk_known,
216 * smk_tskacc - determine if a task has a specific access to an object
217 * @tsp: a pointer to the subject's task
218 * @obj_known: a pointer to the object's label entry
219 * @mode: the access requested, in "MAY" format
220 * @a : common audit data
222 * This function checks the subject task's label/object label pair
223 * in the access rule list and returns 0 if the access is permitted,
224 * non zero otherwise. It allows that the task may have the capability
225 * to override the rules.
227 int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
228 u32 mode, struct smk_audit_info *a)
230 struct smack_known *sbj_known = smk_of_task(tsp);
235 * Check the global rule list
237 rc = smk_access(sbj_known, obj_known, mode, NULL);
240 * If there is an entry in the task's rule list
241 * it can further restrict access.
243 may = smk_access_entry(sbj_known->smk_known,
244 obj_known->smk_known,
248 if ((mode & may) == mode)
254 * Allow for priviliged to override policy.
256 if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
262 smack_log(sbj_known->smk_known, obj_known->smk_known,
269 * smk_curacc - determine if current has a specific access to an object
270 * @obj_known: a pointer to the object's Smack label entry
271 * @mode: the access requested, in "MAY" format
272 * @a : common audit data
274 * This function checks the current subject label/object label pair
275 * in the access rule list and returns 0 if the access is permitted,
276 * non zero otherwise. It allows that current may have the capability
277 * to override the rules.
279 int smk_curacc(struct smack_known *obj_known,
280 u32 mode, struct smk_audit_info *a)
282 struct task_smack *tsp = current_security();
284 return smk_tskacc(tsp, obj_known, mode, a);
289 * smack_str_from_perm : helper to transalate an int to a
291 * @string : the string to fill
295 static inline void smack_str_from_perm(char *string, int access)
299 if (access & MAY_READ)
301 if (access & MAY_WRITE)
303 if (access & MAY_EXEC)
305 if (access & MAY_APPEND)
307 if (access & MAY_TRANSMUTE)
309 if (access & MAY_LOCK)
314 * smack_log_callback - SMACK specific information
315 * will be called by generic audit code
316 * @ab : the audit_buffer
320 static void smack_log_callback(struct audit_buffer *ab, void *a)
322 struct common_audit_data *ad = a;
323 struct smack_audit_data *sad = ad->smack_audit_data;
324 audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
325 ad->smack_audit_data->function,
326 sad->result ? "denied" : "granted");
327 audit_log_format(ab, " subject=");
328 audit_log_untrustedstring(ab, sad->subject);
329 audit_log_format(ab, " object=");
330 audit_log_untrustedstring(ab, sad->object);
331 if (sad->request[0] == '\0')
332 audit_log_format(ab, " labels_differ");
334 audit_log_format(ab, " requested=%s", sad->request);
338 * smack_log - Audit the granting or denial of permissions.
339 * @subject_label : smack label of the requester
340 * @object_label : smack label of the object being accessed
341 * @request: requested permissions
342 * @result: result from smk_access
343 * @a: auxiliary audit data
345 * Audit the granting or denial of permissions in accordance
348 void smack_log(char *subject_label, char *object_label, int request,
349 int result, struct smk_audit_info *ad)
351 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
352 char request_buffer[SMK_NUM_ACCESS_TYPE + 5];
354 char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
356 struct smack_audit_data *sad;
357 struct common_audit_data *a = &ad->a;
359 /* check if we have to log the current event */
360 if (result < 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
362 if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
365 sad = a->smack_audit_data;
367 if (sad->function == NULL)
368 sad->function = "unknown";
370 /* end preparing the audit data */
371 smack_str_from_perm(request_buffer, request);
372 sad->subject = subject_label;
373 sad->object = object_label;
374 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
376 * The result may be positive in bringup mode.
377 * A positive result is an allow, but not for normal reasons.
378 * Mark it as successful, but don't filter it out even if
379 * the logging policy says to do so.
381 if (result == SMACK_UNCONFINED_SUBJECT)
382 strcat(request_buffer, "(US)");
383 else if (result == SMACK_UNCONFINED_OBJECT)
384 strcat(request_buffer, "(UO)");
389 sad->request = request_buffer;
390 sad->result = result;
392 common_lsm_audit(a, smack_log_callback, NULL);
394 #else /* #ifdef CONFIG_AUDIT */
395 void smack_log(char *subject_label, char *object_label, int request,
396 int result, struct smk_audit_info *ad)
401 DEFINE_MUTEX(smack_known_lock);
403 struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
406 * smk_insert_entry - insert a smack label into a hash map,
408 * this function must be called under smack_known_lock
410 void smk_insert_entry(struct smack_known *skp)
413 struct hlist_head *head;
415 hash = full_name_hash(NULL, skp->smk_known, strlen(skp->smk_known));
416 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
418 hlist_add_head_rcu(&skp->smk_hashed, head);
419 list_add_rcu(&skp->list, &smack_known_list);
423 * smk_find_entry - find a label on the list, return the list entry
424 * @string: a text string that might be a Smack label
426 * Returns a pointer to the entry in the label list that
427 * matches the passed string or NULL if not found.
429 struct smack_known *smk_find_entry(const char *string)
432 struct hlist_head *head;
433 struct smack_known *skp;
435 hash = full_name_hash(NULL, string, strlen(string));
436 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
438 hlist_for_each_entry_rcu(skp, head, smk_hashed)
439 if (strcmp(skp->smk_known, string) == 0)
446 * smk_parse_smack - parse smack label from a text string
447 * @string: a text string that might contain a Smack label
448 * @len: the maximum size, or zero if it is NULL terminated.
450 * Returns a pointer to the clean label or an error code.
452 char *smk_parse_smack(const char *string, int len)
458 len = strlen(string) + 1;
461 * Reserve a leading '-' as an indicator that
462 * this isn't a label, but an option to interfaces
463 * including /smack/cipso and /smack/cipso2
465 if (string[0] == '-')
466 return ERR_PTR(-EINVAL);
468 for (i = 0; i < len; i++)
469 if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
470 string[i] == '"' || string[i] == '\\' || string[i] == '\'')
473 if (i == 0 || i >= SMK_LONGLABEL)
474 return ERR_PTR(-EINVAL);
476 smack = kzalloc(i + 1, GFP_NOFS);
478 return ERR_PTR(-ENOMEM);
480 strncpy(smack, string, i);
486 * smk_netlbl_mls - convert a catset to netlabel mls categories
487 * @catset: the Smack categories
488 * @sap: where to put the netlabel categories
490 * Allocates and fills attr.mls
491 * Returns 0 on success, error code on failure.
493 int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
502 sap->flags |= NETLBL_SECATTR_MLS_CAT;
503 sap->attr.mls.lvl = level;
504 sap->attr.mls.cat = NULL;
506 for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
507 for (m = 0x80; m != 0; m >>= 1, cat++) {
510 rc = netlbl_catmap_setbit(&sap->attr.mls.cat,
513 netlbl_catmap_free(sap->attr.mls.cat);
522 * smk_import_entry - import a label, return the list entry
523 * @string: a text string that might be a Smack label
524 * @len: the maximum size, or zero if it is NULL terminated.
526 * Returns a pointer to the entry in the label list that
527 * matches the passed string, adding it if necessary,
530 struct smack_known *smk_import_entry(const char *string, int len)
532 struct smack_known *skp;
537 smack = smk_parse_smack(string, len);
539 return ERR_CAST(smack);
541 mutex_lock(&smack_known_lock);
543 skp = smk_find_entry(smack);
547 skp = kzalloc(sizeof(*skp), GFP_NOFS);
549 skp = ERR_PTR(-ENOMEM);
553 skp->smk_known = smack;
554 skp->smk_secid = smack_next_secid++;
555 skp->smk_netlabel.domain = skp->smk_known;
556 skp->smk_netlabel.flags =
557 NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
559 * If direct labeling works use it.
560 * Otherwise use mapped labeling.
562 slen = strlen(smack);
563 if (slen < SMK_CIPSOLEN)
564 rc = smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
565 &skp->smk_netlabel, slen);
567 rc = smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
568 &skp->smk_netlabel, sizeof(skp->smk_secid));
571 INIT_LIST_HEAD(&skp->smk_rules);
572 mutex_init(&skp->smk_rules_lock);
574 * Make sure that the entry is actually
575 * filled before putting it on the list.
577 smk_insert_entry(skp);
581 * smk_netlbl_mls failed.
588 mutex_unlock(&smack_known_lock);
594 * smack_from_secid - find the Smack label associated with a secid
595 * @secid: an integer that might be associated with a Smack label
597 * Returns a pointer to the appropriate Smack label entry if there is one,
598 * otherwise a pointer to the invalid Smack label.
600 struct smack_known *smack_from_secid(const u32 secid)
602 struct smack_known *skp;
605 list_for_each_entry_rcu(skp, &smack_known_list, list) {
606 if (skp->smk_secid == secid) {
613 * If we got this far someone asked for the translation
614 * of a secid that is not on the list.
617 return &smack_known_invalid;
621 * Unless a process is running with one of these labels
622 * even having CAP_MAC_OVERRIDE isn't enough to grant
623 * privilege to violate MAC policy. If no labels are
624 * designated (the empty list case) capabilities apply to
627 LIST_HEAD(smack_onlycap_list);
628 DEFINE_MUTEX(smack_onlycap_lock);
631 * Is the task privileged and allowed to be privileged
632 * by the onlycap rule.
634 * Returns 1 if the task is allowed to be privileged, 0 if it's not.
636 int smack_privileged(int cap)
638 struct smack_known *skp = smk_of_current();
639 struct smack_known_list_elem *sklep;
642 * All kernel tasks are privileged
644 if (unlikely(current->flags & PF_KTHREAD))
651 if (list_empty(&smack_onlycap_list)) {
656 list_for_each_entry_rcu(sklep, &smack_onlycap_list, list) {
657 if (sklep->smk_label == skp) {