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 == 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_label: a pointer to the subject's Smack label
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(char *subject_label, char *object_label, int request,
126 struct smk_audit_info *a)
128 struct smack_known *skp;
133 * Hardcoded comparisons.
135 * A star subject can't access any object.
137 if (subject_label == smack_known_star.smk_known) {
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_label == smack_known_web.smk_known)
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_label == object_label)
161 * A hat subject can read any object.
162 * A floor object can be read by any subject.
164 if ((request & MAY_ANYREAD) == request) {
165 if (object_label == smack_known_floor.smk_known)
167 if (subject_label == smack_known_hat.smk_known)
171 * Beyond here an explicit relationship is required.
172 * If the requested access is contained in the available
173 * access (e.g. read is included in readwrite) it's
174 * good. A negative response from smk_access_entry()
175 * indicates there is no entry for this pair.
177 skp = smk_find_entry(subject_label);
179 may = smk_access_entry(subject_label, object_label, &skp->smk_rules);
182 if (may > 0 && (request & may) == request)
189 smack_log(subject_label, object_label, request, rc, a);
195 * smk_curacc - determine if current has a specific access to an object
196 * @obj_label: a pointer to the object's Smack label
197 * @mode: the access requested, in "MAY" format
198 * @a : common audit data
200 * This function checks the current subject label/object label pair
201 * in the access rule list and returns 0 if the access is permitted,
202 * non zero otherwise. It allows that current may have the capability
203 * to override the rules.
205 int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a)
207 struct task_smack *tsp = current_security();
208 char *sp = smk_of_task(tsp);
213 * Check the global rule list
215 rc = smk_access(sp, obj_label, mode, NULL);
218 * If there is an entry in the task's rule list
219 * it can further restrict access.
221 may = smk_access_entry(sp, obj_label, &tsp->smk_rules);
224 if ((mode & may) == mode)
230 * Allow for priviliged to override policy.
232 if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
238 smack_log(sp, obj_label, mode, rc, a);
245 * smack_str_from_perm : helper to transalate an int to a
247 * @string : the string to fill
251 static inline void smack_str_from_perm(char *string, int access)
254 if (access & MAY_READ)
256 if (access & MAY_WRITE)
258 if (access & MAY_EXEC)
260 if (access & MAY_APPEND)
262 if (access & MAY_TRANSMUTE)
264 if (access & MAY_LOCK)
269 * smack_log_callback - SMACK specific information
270 * will be called by generic audit code
271 * @ab : the audit_buffer
275 static void smack_log_callback(struct audit_buffer *ab, void *a)
277 struct common_audit_data *ad = a;
278 struct smack_audit_data *sad = &ad->smack_audit_data;
279 audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
280 ad->smack_audit_data.function,
281 sad->result ? "denied" : "granted");
282 audit_log_format(ab, " subject=");
283 audit_log_untrustedstring(ab, sad->subject);
284 audit_log_format(ab, " object=");
285 audit_log_untrustedstring(ab, sad->object);
286 audit_log_format(ab, " requested=%s", sad->request);
290 * smack_log - Audit the granting or denial of permissions.
291 * @subject_label : smack label of the requester
292 * @object_label : smack label of the object being accessed
293 * @request: requested permissions
294 * @result: result from smk_access
295 * @a: auxiliary audit data
297 * Audit the granting or denial of permissions in accordance
300 void smack_log(char *subject_label, char *object_label, int request,
301 int result, struct smk_audit_info *ad)
303 char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
304 struct smack_audit_data *sad;
305 struct common_audit_data *a = &ad->a;
307 /* check if we have to log the current event */
308 if (result != 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
310 if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
313 if (a->smack_audit_data.function == NULL)
314 a->smack_audit_data.function = "unknown";
316 /* end preparing the audit data */
317 sad = &a->smack_audit_data;
318 smack_str_from_perm(request_buffer, request);
319 sad->subject = subject_label;
320 sad->object = object_label;
321 sad->request = request_buffer;
322 sad->result = result;
323 a->lsm_pre_audit = smack_log_callback;
327 #else /* #ifdef CONFIG_AUDIT */
328 void smack_log(char *subject_label, char *object_label, int request,
329 int result, struct smk_audit_info *ad)
334 DEFINE_MUTEX(smack_known_lock);
337 * smk_find_entry - find a label on the list, return the list entry
338 * @string: a text string that might be a Smack label
340 * Returns a pointer to the entry in the label list that
341 * matches the passed string.
343 struct smack_known *smk_find_entry(const char *string)
345 struct smack_known *skp;
347 list_for_each_entry_rcu(skp, &smack_known_list, list) {
348 if (strcmp(skp->smk_known, string) == 0)
356 * smk_parse_smack - parse smack label from a text string
357 * @string: a text string that might contain a Smack label
358 * @len: the maximum size, or zero if it is NULL terminated.
360 * Returns a pointer to the clean label, or NULL
362 char *smk_parse_smack(const char *string, int len)
368 len = strlen(string) + 1;
371 * Reserve a leading '-' as an indicator that
372 * this isn't a label, but an option to interfaces
373 * including /smack/cipso and /smack/cipso2
375 if (string[0] == '-')
378 for (i = 0; i < len; i++)
379 if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
380 string[i] == '"' || string[i] == '\\' || string[i] == '\'')
383 if (i == 0 || i >= SMK_LONGLABEL)
386 smack = kzalloc(i + 1, GFP_KERNEL);
388 strncpy(smack, string, i + 1);
395 * smk_netlbl_mls - convert a catset to netlabel mls categories
396 * @catset: the Smack categories
397 * @sap: where to put the netlabel categories
399 * Allocates and fills attr.mls
400 * Returns 0 on success, error code on failure.
402 int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
411 sap->flags |= NETLBL_SECATTR_MLS_CAT;
412 sap->attr.mls.lvl = level;
413 sap->attr.mls.cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
414 sap->attr.mls.cat->startbit = 0;
416 for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
417 for (m = 0x80; m != 0; m >>= 1, cat++) {
420 rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat,
423 netlbl_secattr_catmap_free(sap->attr.mls.cat);
432 * smk_import_entry - import a label, return the list entry
433 * @string: a text string that might be a Smack label
434 * @len: the maximum size, or zero if it is NULL terminated.
436 * Returns a pointer to the entry in the label list that
437 * matches the passed string, adding it if necessary.
439 struct smack_known *smk_import_entry(const char *string, int len)
441 struct smack_known *skp;
446 smack = smk_parse_smack(string, len);
450 mutex_lock(&smack_known_lock);
452 skp = smk_find_entry(smack);
456 skp = kzalloc(sizeof(*skp), GFP_KERNEL);
460 skp->smk_known = smack;
461 skp->smk_secid = smack_next_secid++;
462 skp->smk_netlabel.domain = skp->smk_known;
463 skp->smk_netlabel.flags =
464 NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
466 * If direct labeling works use it.
467 * Otherwise use mapped labeling.
469 slen = strlen(smack);
470 if (slen < SMK_CIPSOLEN)
471 rc = smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
472 &skp->smk_netlabel, slen);
474 rc = smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
475 &skp->smk_netlabel, sizeof(skp->smk_secid));
478 INIT_LIST_HEAD(&skp->smk_rules);
479 mutex_init(&skp->smk_rules_lock);
481 * Make sure that the entry is actually
482 * filled before putting it on the list.
484 list_add_rcu(&skp->list, &smack_known_list);
488 * smk_netlbl_mls failed.
495 mutex_unlock(&smack_known_lock);
501 * smk_import - import a smack label
502 * @string: a text string that might be a Smack label
503 * @len: the maximum size, or zero if it is NULL terminated.
505 * Returns a pointer to the label in the label list that
506 * matches the passed string, adding it if necessary.
508 char *smk_import(const char *string, int len)
510 struct smack_known *skp;
512 /* labels cannot begin with a '-' */
513 if (string[0] == '-')
515 skp = smk_import_entry(string, len);
518 return skp->smk_known;
522 * smack_from_secid - find the Smack label associated with a secid
523 * @secid: an integer that might be associated with a Smack label
525 * Returns a pointer to the appropriate Smack label if there is one,
526 * otherwise a pointer to the invalid Smack label.
528 char *smack_from_secid(const u32 secid)
530 struct smack_known *skp;
533 list_for_each_entry_rcu(skp, &smack_known_list, list) {
534 if (skp->smk_secid == secid) {
536 return skp->smk_known;
541 * If we got this far someone asked for the translation
542 * of a secid that is not on the list.
545 return smack_known_invalid.smk_known;
549 * smack_to_secid - find the secid associated with a Smack label
550 * @smack: the Smack label
552 * Returns the appropriate secid if there is one,
555 u32 smack_to_secid(const char *smack)
557 struct smack_known *skp = smk_find_entry(smack);
561 return skp->smk_secid;