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 int smk_access_entry(char *subject_label, char *object_label,
89 struct list_head *rule_list)
92 struct smack_rule *srp;
94 list_for_each_entry_rcu(srp, rule_list, list) {
95 if (srp->smk_object == object_label &&
96 srp->smk_subject->smk_known == subject_label) {
97 may = srp->smk_access;
106 * smk_access - determine if a subject has a specific access to an object
107 * @subject_known: a pointer to the subject's Smack label entry
108 * @object_label: a pointer to the object's Smack label
109 * @request: the access requested, in "MAY" format
110 * @a : a pointer to the audit data
112 * This function looks up the subject/object pair in the
113 * access rule list and returns 0 if the access is permitted,
114 * non zero otherwise.
116 * Smack labels are shared on smack_list
118 int smk_access(struct smack_known *subject_known, char *object_label,
119 int request, struct smk_audit_info *a)
125 * Hardcoded comparisons.
127 * A star subject can't access any object.
129 if (subject_known == &smack_known_star) {
134 * An internet object can be accessed by any subject.
135 * Tasks cannot be assigned the internet label.
136 * An internet subject can access any object.
138 if (object_label == smack_known_web.smk_known ||
139 subject_known == &smack_known_web)
142 * A star object can be accessed by any subject.
144 if (object_label == smack_known_star.smk_known)
147 * An object can be accessed in any way by a subject
148 * with the same label.
150 if (subject_known->smk_known == object_label)
153 * A hat subject can read any object.
154 * A floor object can be read by any subject.
156 if ((request & MAY_ANYREAD) == request) {
157 if (object_label == smack_known_floor.smk_known)
159 if (subject_known == &smack_known_hat)
163 * Beyond here an explicit relationship is required.
164 * If the requested access is contained in the available
165 * access (e.g. read is included in readwrite) it's
166 * good. A negative response from smk_access_entry()
167 * indicates there is no entry for this pair.
170 may = smk_access_entry(subject_known->smk_known, object_label,
171 &subject_known->smk_rules);
174 if (may > 0 && (request & may) == request)
181 smack_log(subject_known->smk_known, object_label, request,
188 * smk_curacc - determine if current has a specific access to an object
189 * @obj_label: a pointer to the object's Smack label
190 * @mode: the access requested, in "MAY" format
191 * @a : common audit data
193 * This function checks the current subject label/object label pair
194 * in the access rule list and returns 0 if the access is permitted,
195 * non zero otherwise. It allows that current may have the capability
196 * to override the rules.
198 int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a)
200 struct task_smack *tsp = current_security();
201 struct smack_known *skp = smk_of_task(tsp);
206 * Check the global rule list
208 rc = smk_access(skp, obj_label, mode, NULL);
211 * If there is an entry in the task's rule list
212 * it can further restrict access.
214 may = smk_access_entry(skp->smk_known, obj_label,
218 if ((mode & may) == mode)
224 * Allow for priviliged to override policy.
226 if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
232 smack_log(skp->smk_known, obj_label, mode, rc, a);
239 * smack_str_from_perm : helper to transalate an int to a
241 * @string : the string to fill
245 static inline void smack_str_from_perm(char *string, int access)
248 if (access & MAY_READ)
250 if (access & MAY_WRITE)
252 if (access & MAY_EXEC)
254 if (access & MAY_APPEND)
256 if (access & MAY_TRANSMUTE)
261 * smack_log_callback - SMACK specific information
262 * will be called by generic audit code
263 * @ab : the audit_buffer
267 static void smack_log_callback(struct audit_buffer *ab, void *a)
269 struct common_audit_data *ad = a;
270 struct smack_audit_data *sad = ad->smack_audit_data;
271 audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
272 ad->smack_audit_data->function,
273 sad->result ? "denied" : "granted");
274 audit_log_format(ab, " subject=");
275 audit_log_untrustedstring(ab, sad->subject);
276 audit_log_format(ab, " object=");
277 audit_log_untrustedstring(ab, sad->object);
278 audit_log_format(ab, " requested=%s", sad->request);
282 * smack_log - Audit the granting or denial of permissions.
283 * @subject_label : smack label of the requester
284 * @object_label : smack label of the object being accessed
285 * @request: requested permissions
286 * @result: result from smk_access
287 * @a: auxiliary audit data
289 * Audit the granting or denial of permissions in accordance
292 void smack_log(char *subject_label, char *object_label, int request,
293 int result, struct smk_audit_info *ad)
295 char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
296 struct smack_audit_data *sad;
297 struct common_audit_data *a = &ad->a;
299 /* check if we have to log the current event */
300 if (result != 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
302 if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
305 sad = a->smack_audit_data;
307 if (sad->function == NULL)
308 sad->function = "unknown";
310 /* end preparing the audit data */
311 smack_str_from_perm(request_buffer, request);
312 sad->subject = subject_label;
313 sad->object = object_label;
314 sad->request = request_buffer;
315 sad->result = result;
317 common_lsm_audit(a, smack_log_callback, NULL);
319 #else /* #ifdef CONFIG_AUDIT */
320 void smack_log(char *subject_label, char *object_label, int request,
321 int result, struct smk_audit_info *ad)
326 DEFINE_MUTEX(smack_known_lock);
329 * smk_find_entry - find a label on the list, return the list entry
330 * @string: a text string that might be a Smack label
332 * Returns a pointer to the entry in the label list that
333 * matches the passed string.
335 struct smack_known *smk_find_entry(const char *string)
337 struct smack_known *skp;
339 list_for_each_entry_rcu(skp, &smack_known_list, list) {
340 if (strcmp(skp->smk_known, string) == 0)
348 * smk_parse_smack - parse smack label from a text string
349 * @string: a text string that might contain a Smack label
350 * @len: the maximum size, or zero if it is NULL terminated.
352 * Returns a pointer to the clean label, or NULL
354 char *smk_parse_smack(const char *string, int len)
360 len = strlen(string) + 1;
363 * Reserve a leading '-' as an indicator that
364 * this isn't a label, but an option to interfaces
365 * including /smack/cipso and /smack/cipso2
367 if (string[0] == '-')
370 for (i = 0; i < len; i++)
371 if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
372 string[i] == '"' || string[i] == '\\' || string[i] == '\'')
375 if (i == 0 || i >= SMK_LONGLABEL)
378 smack = kzalloc(i + 1, GFP_KERNEL);
380 strncpy(smack, string, i + 1);
387 * smk_netlbl_mls - convert a catset to netlabel mls categories
388 * @catset: the Smack categories
389 * @sap: where to put the netlabel categories
391 * Allocates and fills attr.mls
392 * Returns 0 on success, error code on failure.
394 int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
403 sap->flags |= NETLBL_SECATTR_MLS_CAT;
404 sap->attr.mls.lvl = level;
405 sap->attr.mls.cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
406 if (!sap->attr.mls.cat)
408 sap->attr.mls.cat->startbit = 0;
410 for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
411 for (m = 0x80; m != 0; m >>= 1, cat++) {
414 rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat,
417 netlbl_secattr_catmap_free(sap->attr.mls.cat);
426 * smk_import_entry - import a label, return the list entry
427 * @string: a text string that might be a Smack label
428 * @len: the maximum size, or zero if it is NULL terminated.
430 * Returns a pointer to the entry in the label list that
431 * matches the passed string, adding it if necessary.
433 struct smack_known *smk_import_entry(const char *string, int len)
435 struct smack_known *skp;
440 smack = smk_parse_smack(string, len);
444 mutex_lock(&smack_known_lock);
446 skp = smk_find_entry(smack);
450 skp = kzalloc(sizeof(*skp), GFP_KERNEL);
454 skp->smk_known = smack;
455 skp->smk_secid = smack_next_secid++;
456 skp->smk_netlabel.domain = skp->smk_known;
457 skp->smk_netlabel.flags =
458 NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
460 * If direct labeling works use it.
461 * Otherwise use mapped labeling.
463 slen = strlen(smack);
464 if (slen < SMK_CIPSOLEN)
465 rc = smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
466 &skp->smk_netlabel, slen);
468 rc = smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
469 &skp->smk_netlabel, sizeof(skp->smk_secid));
472 INIT_LIST_HEAD(&skp->smk_rules);
473 mutex_init(&skp->smk_rules_lock);
475 * Make sure that the entry is actually
476 * filled before putting it on the list.
478 list_add_rcu(&skp->list, &smack_known_list);
482 * smk_netlbl_mls failed.
489 mutex_unlock(&smack_known_lock);
495 * smk_import - import a smack label
496 * @string: a text string that might be a Smack label
497 * @len: the maximum size, or zero if it is NULL terminated.
499 * Returns a pointer to the label in the label list that
500 * matches the passed string, adding it if necessary.
502 char *smk_import(const char *string, int len)
504 struct smack_known *skp;
506 /* labels cannot begin with a '-' */
507 if (string[0] == '-')
509 skp = smk_import_entry(string, len);
512 return skp->smk_known;
516 * smack_from_secid - find the Smack label associated with a secid
517 * @secid: an integer that might be associated with a Smack label
519 * Returns a pointer to the appropriate Smack label entry if there is one,
520 * otherwise a pointer to the invalid Smack label.
522 struct smack_known *smack_from_secid(const u32 secid)
524 struct smack_known *skp;
527 list_for_each_entry_rcu(skp, &smack_known_list, list) {
528 if (skp->smk_secid == secid) {
535 * If we got this far someone asked for the translation
536 * of a secid that is not on the list.
539 return &smack_known_invalid;
543 * smack_to_secid - find the secid associated with a Smack label
544 * @smack: the Smack label
546 * Returns the appropriate secid if there is one,
549 u32 smack_to_secid(const char *smack)
551 struct smack_known *skp = smk_find_entry(smack);
555 return skp->smk_secid;