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->smk_known == 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: a pointer to the subject's Smack label entry
115 * @object: a pointer to the object's Smack label entry
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, struct smack_known *object,
126 int request, struct smk_audit_info *a)
132 * 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 ||
146 subject == &smack_known_web)
149 * A star object can be accessed by any subject.
151 if (object == &smack_known_star)
154 * An object can be accessed in any way by a subject
155 * with the same label.
157 if (subject->smk_known == object->smk_known)
160 * A hat subject can read any object.
161 * A floor object can be read by any subject.
163 if ((request & MAY_ANYREAD) == 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)
198 smack_log(subject->smk_known, object->smk_known,
206 * smk_tskacc - determine if a task has a specific access to an object
207 * @tsp: a pointer to the subject's task
208 * @obj_known: a pointer to the object's label entry
209 * @mode: the access requested, in "MAY" format
210 * @a : common audit data
212 * This function checks the subject task's label/object label pair
213 * in the access rule list and returns 0 if the access is permitted,
214 * non zero otherwise. It allows that the task may have the capability
215 * to override the rules.
217 int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
218 u32 mode, struct smk_audit_info *a)
220 struct smack_known *sbj_known = smk_of_task(tsp);
225 * Check the global rule list
227 rc = smk_access(sbj_known, obj_known, mode, NULL);
230 * If there is an entry in the task's rule list
231 * it can further restrict access.
233 may = smk_access_entry(sbj_known->smk_known,
234 obj_known->smk_known,
238 if ((mode & may) == mode)
244 * Allow for priviliged to override policy.
246 if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
252 smack_log(sbj_known->smk_known, obj_known->smk_known,
259 * smk_curacc - determine if current has a specific access to an object
260 * @obj_known: a pointer to the object's Smack label entry
261 * @mode: the access requested, in "MAY" format
262 * @a : common audit data
264 * This function checks the current subject label/object label pair
265 * in the access rule list and returns 0 if the access is permitted,
266 * non zero otherwise. It allows that current may have the capability
267 * to override the rules.
269 int smk_curacc(struct smack_known *obj_known,
270 u32 mode, struct smk_audit_info *a)
272 struct task_smack *tsp = current_security();
274 return smk_tskacc(tsp, obj_known, mode, a);
279 * smack_str_from_perm : helper to transalate an int to a
281 * @string : the string to fill
285 static inline void smack_str_from_perm(char *string, int access)
289 if (access & MAY_READ)
291 if (access & MAY_WRITE)
293 if (access & MAY_EXEC)
295 if (access & MAY_APPEND)
297 if (access & MAY_TRANSMUTE)
299 if (access & MAY_LOCK)
304 * smack_log_callback - SMACK specific information
305 * will be called by generic audit code
306 * @ab : the audit_buffer
310 static void smack_log_callback(struct audit_buffer *ab, void *a)
312 struct common_audit_data *ad = a;
313 struct smack_audit_data *sad = ad->smack_audit_data;
314 audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
315 ad->smack_audit_data->function,
316 sad->result ? "denied" : "granted");
317 audit_log_format(ab, " subject=");
318 audit_log_untrustedstring(ab, sad->subject);
319 audit_log_format(ab, " object=");
320 audit_log_untrustedstring(ab, sad->object);
321 if (sad->request[0] == '\0')
322 audit_log_format(ab, " labels_differ");
324 audit_log_format(ab, " requested=%s", sad->request);
328 * smack_log - Audit the granting or denial of permissions.
329 * @subject_label : smack label of the requester
330 * @object_label : smack label of the object being accessed
331 * @request: requested permissions
332 * @result: result from smk_access
333 * @a: auxiliary audit data
335 * Audit the granting or denial of permissions in accordance
338 void smack_log(char *subject_label, char *object_label, int request,
339 int result, struct smk_audit_info *ad)
341 char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
342 struct smack_audit_data *sad;
343 struct common_audit_data *a = &ad->a;
345 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
347 * The result may be positive in bringup mode.
352 /* check if we have to log the current event */
353 if (result != 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
355 if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
358 sad = a->smack_audit_data;
360 if (sad->function == NULL)
361 sad->function = "unknown";
363 /* end preparing the audit data */
364 smack_str_from_perm(request_buffer, request);
365 sad->subject = subject_label;
366 sad->object = object_label;
367 sad->request = request_buffer;
368 sad->result = result;
370 common_lsm_audit(a, smack_log_callback, NULL);
372 #else /* #ifdef CONFIG_AUDIT */
373 void smack_log(char *subject_label, char *object_label, int request,
374 int result, struct smk_audit_info *ad)
379 DEFINE_MUTEX(smack_known_lock);
381 struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
384 * smk_insert_entry - insert a smack label into a hash map,
386 * this function must be called under smack_known_lock
388 void smk_insert_entry(struct smack_known *skp)
391 struct hlist_head *head;
393 hash = full_name_hash(skp->smk_known, strlen(skp->smk_known));
394 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
396 hlist_add_head_rcu(&skp->smk_hashed, head);
397 list_add_rcu(&skp->list, &smack_known_list);
401 * smk_find_entry - find a label on the list, return the list entry
402 * @string: a text string that might be a Smack label
404 * Returns a pointer to the entry in the label list that
405 * matches the passed string.
407 struct smack_known *smk_find_entry(const char *string)
410 struct hlist_head *head;
411 struct smack_known *skp;
413 hash = full_name_hash(string, strlen(string));
414 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
416 hlist_for_each_entry_rcu(skp, head, smk_hashed)
417 if (strcmp(skp->smk_known, string) == 0)
424 * smk_parse_smack - parse smack label from a text string
425 * @string: a text string that might contain a Smack label
426 * @len: the maximum size, or zero if it is NULL terminated.
428 * Returns a pointer to the clean label, or NULL
430 char *smk_parse_smack(const char *string, int len)
436 len = strlen(string) + 1;
439 * Reserve a leading '-' as an indicator that
440 * this isn't a label, but an option to interfaces
441 * including /smack/cipso and /smack/cipso2
443 if (string[0] == '-')
446 for (i = 0; i < len; i++)
447 if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
448 string[i] == '"' || string[i] == '\\' || string[i] == '\'')
451 if (i == 0 || i >= SMK_LONGLABEL)
454 smack = kzalloc(i + 1, GFP_KERNEL);
456 strncpy(smack, string, i + 1);
463 * smk_netlbl_mls - convert a catset to netlabel mls categories
464 * @catset: the Smack categories
465 * @sap: where to put the netlabel categories
467 * Allocates and fills attr.mls
468 * Returns 0 on success, error code on failure.
470 int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
479 sap->flags |= NETLBL_SECATTR_MLS_CAT;
480 sap->attr.mls.lvl = level;
481 sap->attr.mls.cat = NULL;
483 for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
484 for (m = 0x80; m != 0; m >>= 1, cat++) {
487 rc = netlbl_catmap_setbit(&sap->attr.mls.cat,
490 netlbl_catmap_free(sap->attr.mls.cat);
499 * smk_import_entry - import a label, return the list entry
500 * @string: a text string that might be a Smack label
501 * @len: the maximum size, or zero if it is NULL terminated.
503 * Returns a pointer to the entry in the label list that
504 * matches the passed string, adding it if necessary.
506 struct smack_known *smk_import_entry(const char *string, int len)
508 struct smack_known *skp;
513 smack = smk_parse_smack(string, len);
517 mutex_lock(&smack_known_lock);
519 skp = smk_find_entry(smack);
523 skp = kzalloc(sizeof(*skp), GFP_KERNEL);
527 skp->smk_known = smack;
528 skp->smk_secid = smack_next_secid++;
529 skp->smk_netlabel.domain = skp->smk_known;
530 skp->smk_netlabel.flags =
531 NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
533 * If direct labeling works use it.
534 * Otherwise use mapped labeling.
536 slen = strlen(smack);
537 if (slen < SMK_CIPSOLEN)
538 rc = smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
539 &skp->smk_netlabel, slen);
541 rc = smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
542 &skp->smk_netlabel, sizeof(skp->smk_secid));
545 INIT_LIST_HEAD(&skp->smk_rules);
546 mutex_init(&skp->smk_rules_lock);
548 * Make sure that the entry is actually
549 * filled before putting it on the list.
551 smk_insert_entry(skp);
555 * smk_netlbl_mls failed.
562 mutex_unlock(&smack_known_lock);
568 * smack_from_secid - find the Smack label associated with a secid
569 * @secid: an integer that might be associated with a Smack label
571 * Returns a pointer to the appropriate Smack label entry if there is one,
572 * otherwise a pointer to the invalid Smack label.
574 struct smack_known *smack_from_secid(const u32 secid)
576 struct smack_known *skp;
579 list_for_each_entry_rcu(skp, &smack_known_list, list) {
580 if (skp->smk_secid == secid) {
587 * If we got this far someone asked for the translation
588 * of a secid that is not on the list.
591 return &smack_known_invalid;