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)
94 struct smack_rule *srp;
96 list_for_each_entry_rcu(srp, rule_list, list) {
97 if (srp->smk_object == object_label &&
98 srp->smk_subject->smk_known == subject_label) {
99 may = srp->smk_access;
105 * MAY_WRITE implies MAY_LOCK.
107 if ((may & MAY_WRITE) == MAY_WRITE)
113 * smk_access - determine if a subject has a specific access to an object
114 * @subject_known: a pointer to the subject's Smack label entry
115 * @object_label: a pointer to the object's Smack label
116 * @request: the access requested, in "MAY" format
117 * @a : a pointer to the audit data
119 * This function looks up the subject/object pair in the
120 * access rule list and returns 0 if the access is permitted,
121 * non zero otherwise.
123 * Smack labels are shared on smack_list
125 int smk_access(struct smack_known *subject_known, char *object_label,
126 int request, struct smk_audit_info *a)
132 * Hardcoded comparisons.
135 * A star subject can't access any object.
137 if (subject_known == &smack_known_star) {
142 * An internet object can be accessed by any subject.
143 * Tasks cannot be assigned the internet label.
144 * An internet subject can access any object.
146 if (object_label == smack_known_web.smk_known ||
147 subject_known == &smack_known_web)
150 * A star object can be accessed by any subject.
152 if (object_label == smack_known_star.smk_known)
155 * An object can be accessed in any way by a subject
156 * with the same label.
158 if (subject_known->smk_known == object_label)
161 * A hat subject can read or lock any object.
162 * A floor object can be read or locked by any subject.
164 if ((request & MAY_ANYREAD) == request ||
165 (request & MAY_LOCK) == request) {
166 if (object_label == smack_known_floor.smk_known)
168 if (subject_known == &smack_known_hat)
172 * Beyond here an explicit relationship is required.
173 * If the requested access is contained in the available
174 * access (e.g. read is included in readwrite) it's
175 * good. A negative response from smk_access_entry()
176 * indicates there is no entry for this pair.
179 may = smk_access_entry(subject_known->smk_known, object_label,
180 &subject_known->smk_rules);
183 if (may <= 0 || (request & may) != request) {
187 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
189 * Return a positive value if using bringup mode.
190 * This allows the hooks to identify checks that
191 * succeed because of "b" rules.
193 if (may & MAY_BRINGUP)
194 rc = SMACK_BRINGUP_ALLOW;
199 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
201 if (smack_unconfined != NULL) {
202 if (object_label == smack_unconfined->smk_known)
203 rc = SMACK_UNCONFINED_OBJECT;
204 if (subject_known->smk_known == smack_unconfined->smk_known)
205 rc = SMACK_UNCONFINED_SUBJECT;
212 smack_log(subject_known->smk_known, object_label, request,
220 * smk_tskacc - determine if a task has a specific access to an object
221 * @tsp: a pointer to the subject task
222 * @obj_label: a pointer to the object's Smack label
223 * @mode: the access requested, in "MAY" format
224 * @a : common audit data
226 * This function checks the subject task's label/object label pair
227 * in the access rule list and returns 0 if the access is permitted,
228 * non zero otherwise. It allows that the task may have the capability
229 * to override the rules.
231 int smk_tskacc(struct task_smack *subject, char *obj_label,
232 u32 mode, struct smk_audit_info *a)
234 struct smack_known *skp = smk_of_task(subject);
239 * Check the global rule list
241 rc = smk_access(skp, obj_label, mode, NULL);
244 * If there is an entry in the task's rule list
245 * it can further restrict access.
247 may = smk_access_entry(skp->smk_known, obj_label,
248 &subject->smk_rules);
251 if ((mode & may) == mode)
257 * Allow for priviliged to override policy.
259 if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
265 smack_log(skp->smk_known, obj_label, mode, rc, a);
271 * smk_curacc - determine if current has a specific access to an object
272 * @obj_label: a pointer to the object's Smack label
273 * @mode: the access requested, in "MAY" format
274 * @a : common audit data
276 * This function checks the current subject label/object label pair
277 * in the access rule list and returns 0 if the access is permitted,
278 * non zero otherwise. It allows that current may have the capability
279 * to override the rules.
281 int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a)
283 struct task_smack *tsp = current_security();
285 return smk_tskacc(tsp, obj_label, mode, a);
290 * smack_str_from_perm : helper to transalate an int to a
292 * @string : the string to fill
296 static inline void smack_str_from_perm(char *string, int access)
300 if (access & MAY_READ)
302 if (access & MAY_WRITE)
304 if (access & MAY_EXEC)
306 if (access & MAY_APPEND)
308 if (access & MAY_TRANSMUTE)
310 if (access & MAY_LOCK)
315 * smack_log_callback - SMACK specific information
316 * will be called by generic audit code
317 * @ab : the audit_buffer
321 static void smack_log_callback(struct audit_buffer *ab, void *a)
323 struct common_audit_data *ad = a;
324 struct smack_audit_data *sad = ad->smack_audit_data;
325 audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
326 ad->smack_audit_data->function,
327 sad->result ? "denied" : "granted");
328 audit_log_format(ab, " subject=");
329 audit_log_untrustedstring(ab, sad->subject);
330 audit_log_format(ab, " object=");
331 audit_log_untrustedstring(ab, sad->object);
332 if (sad->request[0] == '\0')
333 audit_log_format(ab, " labels_differ");
335 audit_log_format(ab, " requested=%s", sad->request);
339 * smack_log - Audit the granting or denial of permissions.
340 * @subject_label : smack label of the requester
341 * @object_label : smack label of the object being accessed
342 * @request: requested permissions
343 * @result: result from smk_access
344 * @a: auxiliary audit data
346 * Audit the granting or denial of permissions in accordance
349 void smack_log(char *subject_label, char *object_label, int request,
350 int result, struct smk_audit_info *ad)
352 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
353 char request_buffer[SMK_NUM_ACCESS_TYPE + 5];
355 char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
357 struct smack_audit_data *sad;
358 struct common_audit_data *a = &ad->a;
360 /* check if we have to log the current event */
361 if (result < 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
363 if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
366 sad = a->smack_audit_data;
368 if (sad->function == NULL)
369 sad->function = "unknown";
371 /* end preparing the audit data */
372 smack_str_from_perm(request_buffer, request);
373 sad->subject = subject_label;
374 sad->object = object_label;
375 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
377 * The result may be positive in bringup mode.
378 * A positive result is an allow, but not for normal reasons.
379 * Mark it as successful, but don't filter it out even if
380 * the logging policy says to do so.
382 if (result == SMACK_UNCONFINED_SUBJECT)
383 strcat(request_buffer, "(US)");
384 else if (result == SMACK_UNCONFINED_OBJECT)
385 strcat(request_buffer, "(UO)");
390 sad->request = request_buffer;
391 sad->result = result;
393 common_lsm_audit(a, smack_log_callback, NULL);
395 #else /* #ifdef CONFIG_AUDIT */
396 void smack_log(char *subject_label, char *object_label, int request,
397 int result, struct smk_audit_info *ad)
402 DEFINE_MUTEX(smack_known_lock);
404 struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
407 * smk_insert_entry - insert a smack label into a hash map,
409 * this function must be called under smack_known_lock
411 void smk_insert_entry(struct smack_known *skp)
414 struct hlist_head *head;
416 hash = full_name_hash(skp->smk_known, strlen(skp->smk_known));
417 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
419 hlist_add_head_rcu(&skp->smk_hashed, head);
420 list_add_rcu(&skp->list, &smack_known_list);
424 * smk_find_entry - find a label on the list, return the list entry
425 * @string: a text string that might be a Smack label
427 * Returns a pointer to the entry in the label list that
428 * matches the passed string.
430 struct smack_known *smk_find_entry(const char *string)
433 struct hlist_head *head;
434 struct smack_known *skp;
436 hash = full_name_hash(string, strlen(string));
437 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
439 hlist_for_each_entry_rcu(skp, head, smk_hashed)
440 if (strcmp(skp->smk_known, string) == 0)
447 * smk_parse_smack - parse smack label from a text string
448 * @string: a text string that might contain a Smack label
449 * @len: the maximum size, or zero if it is NULL terminated.
451 * Returns a pointer to the clean label, or NULL
453 char *smk_parse_smack(const char *string, int len)
459 len = strlen(string) + 1;
462 * Reserve a leading '-' as an indicator that
463 * this isn't a label, but an option to interfaces
464 * including /smack/cipso and /smack/cipso2
466 if (string[0] == '-')
469 for (i = 0; i < len; i++)
470 if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
471 string[i] == '"' || string[i] == '\\' || string[i] == '\'')
474 if (i == 0 || i >= SMK_LONGLABEL)
477 smack = kzalloc(i + 1, GFP_KERNEL);
479 strncpy(smack, string, i + 1);
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 = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
505 if (!sap->attr.mls.cat)
507 sap->attr.mls.cat->startbit = 0;
509 for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
510 for (m = 0x80; m != 0; m >>= 1, cat++) {
513 rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat,
516 netlbl_secattr_catmap_free(sap->attr.mls.cat);
525 * smk_import_entry - import a label, return the list entry
526 * @string: a text string that might be a Smack label
527 * @len: the maximum size, or zero if it is NULL terminated.
529 * Returns a pointer to the entry in the label list that
530 * matches the passed string, adding it if necessary.
532 struct smack_known *smk_import_entry(const char *string, int len)
534 struct smack_known *skp;
539 smack = smk_parse_smack(string, len);
543 mutex_lock(&smack_known_lock);
545 skp = smk_find_entry(smack);
549 skp = kzalloc(sizeof(*skp), GFP_KERNEL);
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 * smk_import - import a smack label
595 * @string: a text string that might be a Smack label
596 * @len: the maximum size, or zero if it is NULL terminated.
598 * Returns a pointer to the label in the label list that
599 * matches the passed string, adding it if necessary.
601 char *smk_import(const char *string, int len)
603 struct smack_known *skp;
605 /* labels cannot begin with a '-' */
606 if (string[0] == '-')
608 skp = smk_import_entry(string, len);
611 return skp->smk_known;
615 * smack_from_secid - find the Smack label associated with a secid
616 * @secid: an integer that might be associated with a Smack label
618 * Returns a pointer to the appropriate Smack label entry if there is one,
619 * otherwise a pointer to the invalid Smack label.
621 struct smack_known *smack_from_secid(const u32 secid)
623 struct smack_known *skp;
626 list_for_each_entry_rcu(skp, &smack_known_list, list) {
627 if (skp->smk_secid == secid) {
634 * If we got this far someone asked for the translation
635 * of a secid that is not on the list.
638 return &smack_known_invalid;
642 * smack_to_secid - find the secid associated with a Smack label
643 * @smack: the Smack label
645 * Returns the appropriate secid if there is one,
648 u32 smack_to_secid(const char *smack)
650 struct smack_known *skp = smk_find_entry(smack);
654 return skp->smk_secid;
658 * Unless a process is running with one of these labels
659 * even having CAP_MAC_OVERRIDE isn't enough to grant
660 * privilege to violate MAC policy. If no labels are
661 * designated (the empty list case) capabilities apply to
664 LIST_HEAD(smack_onlycap_list);
665 DEFINE_MUTEX(smack_onlycap_lock);
668 * Is the task privileged and allowed to be privileged
669 * by the onlycap rule.
671 * Returns 1 if the task is allowed to be privileged, 0 if it's not.
673 int smack_privileged(int cap)
675 struct smack_known *skp = smk_of_current();
676 struct smack_onlycap *sop;
679 * All kernel tasks are privileged
681 if (unlikely(current->flags & PF_KTHREAD))
688 if (list_empty(&smack_onlycap_list)) {
693 list_for_each_entry_rcu(sop, &smack_onlycap_list, list) {
694 if (sop->smk_label == skp) {