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>
15 #include <linux/sched.h>
18 struct smack_known smack_known_huh = {
24 struct smack_known smack_known_hat = {
30 struct smack_known smack_known_star = {
36 struct smack_known smack_known_floor = {
42 struct smack_known smack_known_invalid = {
48 struct smack_known smack_known_web = {
54 LIST_HEAD(smack_known_list);
57 * The initial value needs to be bigger than any of the
60 static u32 smack_next_secid = 10;
63 * what events do we log
64 * can be overwritten at run-time by /smack/logging
66 int log_policy = SMACK_AUDIT_DENIED;
69 * smk_access - determine if a subject has a specific access to an object
70 * @subject_label: a pointer to the subject's Smack label
71 * @object_label: a pointer to the object's Smack label
72 * @request: the access requested, in "MAY" format
73 * @a : a pointer to the audit data
75 * This function looks up the subject/object pair in the
76 * access rule list and returns 0 if the access is permitted,
79 * Even though Smack labels are usually shared on smack_list
80 * labels that come in off the network can't be imported
81 * and added to the list for locking reasons.
83 * Therefore, it is necessary to check the contents of the labels,
84 * not just the pointer values. Of course, in most cases the labels
85 * will be on the list, so checking the pointers may be a worthwhile
88 int smk_access(char *subject_label, char *object_label, int request,
89 struct smk_audit_info *a)
92 struct smack_rule *srp;
96 * Hardcoded comparisons.
98 * A star subject can't access any object.
100 if (subject_label == smack_known_star.smk_known ||
101 strcmp(subject_label, smack_known_star.smk_known) == 0) {
106 * An internet object can be accessed by any subject.
107 * Tasks cannot be assigned the internet label.
108 * An internet subject can access any object.
110 if (object_label == smack_known_web.smk_known ||
111 subject_label == smack_known_web.smk_known ||
112 strcmp(object_label, smack_known_web.smk_known) == 0 ||
113 strcmp(subject_label, smack_known_web.smk_known) == 0)
116 * A star object can be accessed by any subject.
118 if (object_label == smack_known_star.smk_known ||
119 strcmp(object_label, smack_known_star.smk_known) == 0)
122 * An object can be accessed in any way by a subject
123 * with the same label.
125 if (subject_label == object_label ||
126 strcmp(subject_label, object_label) == 0)
129 * A hat subject can read any object.
130 * A floor object can be read by any subject.
132 if ((request & MAY_ANYREAD) == request) {
133 if (object_label == smack_known_floor.smk_known ||
134 strcmp(object_label, smack_known_floor.smk_known) == 0)
136 if (subject_label == smack_known_hat.smk_known ||
137 strcmp(subject_label, smack_known_hat.smk_known) == 0)
141 * Beyond here an explicit relationship is required.
142 * If the requested access is contained in the available
143 * access (e.g. read is included in readwrite) it's
147 list_for_each_entry_rcu(srp, &smack_rule_list, list) {
148 if (srp->smk_subject == subject_label ||
149 strcmp(srp->smk_subject, subject_label) == 0) {
150 if (srp->smk_object == object_label ||
151 strcmp(srp->smk_object, object_label) == 0) {
152 may = srp->smk_access;
159 * This is a bit map operation.
161 if ((request & may) == request)
168 smack_log(subject_label, object_label, request, rc, a);
174 * smk_curacc - determine if current has a specific access to an object
175 * @obj_label: a pointer to the object's Smack label
176 * @mode: the access requested, in "MAY" format
177 * @a : common audit data
179 * This function checks the current subject label/object label pair
180 * in the access rule list and returns 0 if the access is permitted,
181 * non zero otherwise. It allows that current may have the capability
182 * to override the rules.
184 int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a)
187 char *sp = current_security();
189 rc = smk_access(sp, obj_label, mode, NULL);
194 * Return if a specific label has been designated as the
195 * only one that gets privilege and current does not
198 if (smack_onlycap != NULL && smack_onlycap != current->cred->security)
201 if (capable(CAP_MAC_OVERRIDE))
207 smack_log(sp, obj_label, mode, rc, a);
214 * smack_str_from_perm : helper to transalate an int to a
216 * @string : the string to fill
220 static inline void smack_str_from_perm(char *string, int access)
223 if (access & MAY_READ)
225 if (access & MAY_WRITE)
227 if (access & MAY_EXEC)
229 if (access & MAY_APPEND)
234 * smack_log_callback - SMACK specific information
235 * will be called by generic audit code
236 * @ab : the audit_buffer
240 static void smack_log_callback(struct audit_buffer *ab, void *a)
242 struct common_audit_data *ad = a;
243 struct smack_audit_data *sad = &ad->smack_audit_data;
244 audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
245 ad->smack_audit_data.function,
246 sad->result ? "denied" : "granted");
247 audit_log_format(ab, " subject=");
248 audit_log_untrustedstring(ab, sad->subject);
249 audit_log_format(ab, " object=");
250 audit_log_untrustedstring(ab, sad->object);
251 audit_log_format(ab, " requested=%s", sad->request);
255 * smack_log - Audit the granting or denial of permissions.
256 * @subject_label : smack label of the requester
257 * @object_label : smack label of the object being accessed
258 * @request: requested permissions
259 * @result: result from smk_access
260 * @a: auxiliary audit data
262 * Audit the granting or denial of permissions in accordance
265 void smack_log(char *subject_label, char *object_label, int request,
266 int result, struct smk_audit_info *ad)
268 char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
269 struct smack_audit_data *sad;
270 struct common_audit_data *a = &ad->a;
272 /* check if we have to log the current event */
273 if (result != 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
275 if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
278 if (a->smack_audit_data.function == NULL)
279 a->smack_audit_data.function = "unknown";
281 /* end preparing the audit data */
282 sad = &a->smack_audit_data;
283 smack_str_from_perm(request_buffer, request);
284 sad->subject = subject_label;
285 sad->object = object_label;
286 sad->request = request_buffer;
287 sad->result = result;
288 a->lsm_pre_audit = smack_log_callback;
292 #else /* #ifdef CONFIG_AUDIT */
293 void smack_log(char *subject_label, char *object_label, int request,
294 int result, struct smk_audit_info *ad)
299 static DEFINE_MUTEX(smack_known_lock);
302 * smk_import_entry - import a label, return the list entry
303 * @string: a text string that might be a Smack label
304 * @len: the maximum size, or zero if it is NULL terminated.
306 * Returns a pointer to the entry in the label list that
307 * matches the passed string, adding it if necessary.
309 struct smack_known *smk_import_entry(const char *string, int len)
311 struct smack_known *skp;
312 char smack[SMK_LABELLEN];
316 if (len <= 0 || len > SMK_MAXLEN)
319 for (i = 0, found = 0; i < SMK_LABELLEN; i++) {
322 else if (i >= len || string[i] > '~' || string[i] <= ' ' ||
323 string[i] == '/' || string[i] == '"' ||
324 string[i] == '\\' || string[i] == '\'') {
328 smack[i] = string[i];
331 if (smack[0] == '\0')
334 mutex_lock(&smack_known_lock);
337 list_for_each_entry_rcu(skp, &smack_known_list, list) {
338 if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0) {
345 skp = kzalloc(sizeof(struct smack_known), GFP_KERNEL);
347 strncpy(skp->smk_known, smack, SMK_MAXLEN);
348 skp->smk_secid = smack_next_secid++;
349 skp->smk_cipso = NULL;
350 spin_lock_init(&skp->smk_cipsolock);
352 * Make sure that the entry is actually
353 * filled before putting it on the list.
355 list_add_rcu(&skp->list, &smack_known_list);
359 mutex_unlock(&smack_known_lock);
365 * smk_import - import a smack label
366 * @string: a text string that might be a Smack label
367 * @len: the maximum size, or zero if it is NULL terminated.
369 * Returns a pointer to the label in the label list that
370 * matches the passed string, adding it if necessary.
372 char *smk_import(const char *string, int len)
374 struct smack_known *skp;
376 /* labels cannot begin with a '-' */
377 if (string[0] == '-')
379 skp = smk_import_entry(string, len);
382 return skp->smk_known;
386 * smack_from_secid - find the Smack label associated with a secid
387 * @secid: an integer that might be associated with a Smack label
389 * Returns a pointer to the appropraite Smack label if there is one,
390 * otherwise a pointer to the invalid Smack label.
392 char *smack_from_secid(const u32 secid)
394 struct smack_known *skp;
397 list_for_each_entry_rcu(skp, &smack_known_list, list) {
398 if (skp->smk_secid == secid) {
400 return skp->smk_known;
405 * If we got this far someone asked for the translation
406 * of a secid that is not on the list.
409 return smack_known_invalid.smk_known;
413 * smack_to_secid - find the secid associated with a Smack label
414 * @smack: the Smack label
416 * Returns the appropriate secid if there is one,
419 u32 smack_to_secid(const char *smack)
421 struct smack_known *skp;
424 list_for_each_entry_rcu(skp, &smack_known_list, list) {
425 if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0) {
427 return skp->smk_secid;
435 * smack_from_cipso - find the Smack label associated with a CIPSO option
436 * @level: Bell & LaPadula level from the network
437 * @cp: Bell & LaPadula categories from the network
438 * @result: where to put the Smack value
440 * This is a simple lookup in the label table.
442 * This is an odd duck as far as smack handling goes in that
443 * it sends back a copy of the smack label rather than a pointer
444 * to the master list. This is done because it is possible for
445 * a foreign host to send a smack label that is new to this
446 * machine and hence not on the list. That would not be an
447 * issue except that adding an entry to the master list can't
448 * be done at that point.
450 void smack_from_cipso(u32 level, char *cp, char *result)
452 struct smack_known *kp;
456 list_for_each_entry(kp, &smack_known_list, list) {
457 if (kp->smk_cipso == NULL)
460 spin_lock_bh(&kp->smk_cipsolock);
462 if (kp->smk_cipso->smk_level == level &&
463 memcmp(kp->smk_cipso->smk_catset, cp, SMK_LABELLEN) == 0)
464 final = kp->smk_known;
466 spin_unlock_bh(&kp->smk_cipsolock);
470 final = smack_known_huh.smk_known;
471 strncpy(result, final, SMK_MAXLEN);
476 * smack_to_cipso - find the CIPSO option to go with a Smack label
477 * @smack: a pointer to the smack label in question
478 * @cp: where to put the result
480 * Returns zero if a value is available, non-zero otherwise.
482 int smack_to_cipso(const char *smack, struct smack_cipso *cp)
484 struct smack_known *kp;
488 list_for_each_entry_rcu(kp, &smack_known_list, list) {
489 if (kp->smk_known == smack ||
490 strcmp(kp->smk_known, smack) == 0) {
497 if (found == 0 || kp->smk_cipso == NULL)
500 memcpy(cp, kp->smk_cipso, sizeof(struct smack_cipso));