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Casey Schauflere114e472008-02-04 22:29:50 -08001/*
2 * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
3 *
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.
7 *
8 * Author:
9 * Casey Schaufler <casey@schaufler-ca.com>
10 *
11 */
12
13#include <linux/types.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090014#include <linux/slab.h>
Casey Schauflere114e472008-02-04 22:29:50 -080015#include <linux/fs.h>
16#include <linux/sched.h>
17#include "smack.h"
18
Casey Schauflere114e472008-02-04 22:29:50 -080019struct smack_known smack_known_huh = {
Casey Schauflere114e472008-02-04 22:29:50 -080020 .smk_known = "?",
21 .smk_secid = 2,
Casey Schauflere114e472008-02-04 22:29:50 -080022};
23
24struct smack_known smack_known_hat = {
Casey Schauflere114e472008-02-04 22:29:50 -080025 .smk_known = "^",
26 .smk_secid = 3,
Casey Schauflere114e472008-02-04 22:29:50 -080027};
28
29struct smack_known smack_known_star = {
Casey Schauflere114e472008-02-04 22:29:50 -080030 .smk_known = "*",
31 .smk_secid = 4,
Casey Schauflere114e472008-02-04 22:29:50 -080032};
33
34struct smack_known smack_known_floor = {
Casey Schauflere114e472008-02-04 22:29:50 -080035 .smk_known = "_",
36 .smk_secid = 5,
Casey Schauflere114e472008-02-04 22:29:50 -080037};
38
39struct smack_known smack_known_invalid = {
Casey Schauflere114e472008-02-04 22:29:50 -080040 .smk_known = "",
41 .smk_secid = 6,
Casey Schauflere114e472008-02-04 22:29:50 -080042};
43
Casey Schaufler6d3dc072008-12-31 12:54:12 -050044struct smack_known smack_known_web = {
Casey Schaufler6d3dc072008-12-31 12:54:12 -050045 .smk_known = "@",
46 .smk_secid = 7,
Casey Schaufler6d3dc072008-12-31 12:54:12 -050047};
48
Etienne Basset7198e2e2009-03-24 20:53:24 +010049LIST_HEAD(smack_known_list);
Casey Schauflere114e472008-02-04 22:29:50 -080050
51/*
52 * The initial value needs to be bigger than any of the
53 * known values above.
54 */
55static u32 smack_next_secid = 10;
56
Etienne Bassetecfcc532009-04-08 20:40:06 +020057/*
58 * what events do we log
59 * can be overwritten at run-time by /smack/logging
60 */
61int log_policy = SMACK_AUDIT_DENIED;
62
Casey Schauflere114e472008-02-04 22:29:50 -080063/**
Jarkko Sakkinen5c6d1122010-12-07 13:34:01 +020064 * 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
Casey Schaufler7898e1f2011-01-17 08:05:27 -080067 * @rule_list: the list of rules to search
Jarkko Sakkinen5c6d1122010-12-07 13:34:01 +020068 *
69 * This function looks up the subject/object pair in the
Casey Schaufler7898e1f2011-01-17 08:05:27 -080070 * access rule list and returns the access mode. If no
71 * entry is found returns -ENOENT.
Jarkko Sakkinen5c6d1122010-12-07 13:34:01 +020072 *
73 * NOTE:
Jarkko Sakkinen5c6d1122010-12-07 13:34:01 +020074 *
Casey Schaufler272cd7a2011-09-20 12:24:36 -070075 * 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.
84 *
85 * Do the object check first because that is more
86 * likely to differ.
Casey Schauflerc0ab6e52013-10-11 18:06:39 -070087 *
88 * Allowing write access implies allowing locking.
Jarkko Sakkinen5c6d1122010-12-07 13:34:01 +020089 */
Casey Schaufler7898e1f2011-01-17 08:05:27 -080090int smk_access_entry(char *subject_label, char *object_label,
91 struct list_head *rule_list)
Jarkko Sakkinen5c6d1122010-12-07 13:34:01 +020092{
Casey Schaufler7898e1f2011-01-17 08:05:27 -080093 int may = -ENOENT;
Jarkko Sakkinen5c6d1122010-12-07 13:34:01 +020094 struct smack_rule *srp;
95
Casey Schaufler7898e1f2011-01-17 08:05:27 -080096 list_for_each_entry_rcu(srp, rule_list, list) {
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +020097 if (srp->smk_object->smk_known == object_label &&
Casey Schaufler2f823ff2013-05-22 18:43:03 -070098 srp->smk_subject->smk_known == subject_label) {
Casey Schaufler272cd7a2011-09-20 12:24:36 -070099 may = srp->smk_access;
100 break;
Jarkko Sakkinen5c6d1122010-12-07 13:34:01 +0200101 }
102 }
Jarkko Sakkinen5c6d1122010-12-07 13:34:01 +0200103
Casey Schauflerc0ab6e52013-10-11 18:06:39 -0700104 /*
105 * MAY_WRITE implies MAY_LOCK.
106 */
107 if ((may & MAY_WRITE) == MAY_WRITE)
108 may |= MAY_LOCK;
Jarkko Sakkinen5c6d1122010-12-07 13:34:01 +0200109 return may;
110}
111
112/**
Casey Schauflere114e472008-02-04 22:29:50 -0800113 * smk_access - determine if a subject has a specific access to an object
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200114 * @subject: a pointer to the subject's Smack label entry
115 * @object: a pointer to the object's Smack label entry
Casey Schauflere114e472008-02-04 22:29:50 -0800116 * @request: the access requested, in "MAY" format
Etienne Bassetecfcc532009-04-08 20:40:06 +0200117 * @a : a pointer to the audit data
Casey Schauflere114e472008-02-04 22:29:50 -0800118 *
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.
122 *
Casey Schaufler272cd7a2011-09-20 12:24:36 -0700123 * Smack labels are shared on smack_list
Casey Schauflere114e472008-02-04 22:29:50 -0800124 */
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200125int smk_access(struct smack_known *subject, struct smack_known *object,
126 int request, struct smk_audit_info *a)
Casey Schauflere114e472008-02-04 22:29:50 -0800127{
Casey Schaufler7898e1f2011-01-17 08:05:27 -0800128 int may = MAY_NOT;
Etienne Bassetecfcc532009-04-08 20:40:06 +0200129 int rc = 0;
Casey Schauflere114e472008-02-04 22:29:50 -0800130
131 /*
132 * Hardcoded comparisons.
Casey Schauflerbf4b2fe2015-03-21 18:26:40 -0700133 */
134 /*
Casey Schauflere114e472008-02-04 22:29:50 -0800135 * A star subject can't access any object.
136 */
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200137 if (subject == &smack_known_star) {
Etienne Bassetecfcc532009-04-08 20:40:06 +0200138 rc = -EACCES;
139 goto out_audit;
140 }
Casey Schauflere114e472008-02-04 22:29:50 -0800141 /*
Casey Schaufler6d3dc072008-12-31 12:54:12 -0500142 * 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.
145 */
Casey Schaufler6c892df2014-10-09 16:18:55 -0700146 if (object == &smack_known_web || subject == &smack_known_web)
Etienne Bassetecfcc532009-04-08 20:40:06 +0200147 goto out_audit;
Casey Schaufler6d3dc072008-12-31 12:54:12 -0500148 /*
Casey Schauflere114e472008-02-04 22:29:50 -0800149 * A star object can be accessed by any subject.
150 */
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200151 if (object == &smack_known_star)
Etienne Bassetecfcc532009-04-08 20:40:06 +0200152 goto out_audit;
Casey Schauflere114e472008-02-04 22:29:50 -0800153 /*
154 * An object can be accessed in any way by a subject
155 * with the same label.
156 */
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200157 if (subject->smk_known == object->smk_known)
Etienne Bassetecfcc532009-04-08 20:40:06 +0200158 goto out_audit;
Casey Schauflere114e472008-02-04 22:29:50 -0800159 /*
Casey Schaufler6c892df2014-10-09 16:18:55 -0700160 * A hat subject can read or lock any object.
161 * A floor object can be read or locked by any subject.
Casey Schauflere114e472008-02-04 22:29:50 -0800162 */
Casey Schaufler6c892df2014-10-09 16:18:55 -0700163 if ((request & MAY_ANYREAD) == request ||
164 (request & MAY_LOCK) == request) {
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200165 if (object == &smack_known_floor)
Etienne Bassetecfcc532009-04-08 20:40:06 +0200166 goto out_audit;
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200167 if (subject == &smack_known_hat)
Etienne Bassetecfcc532009-04-08 20:40:06 +0200168 goto out_audit;
Casey Schauflere114e472008-02-04 22:29:50 -0800169 }
170 /*
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
Casey Schaufler7898e1f2011-01-17 08:05:27 -0800174 * good. A negative response from smk_access_entry()
175 * indicates there is no entry for this pair.
Casey Schauflere114e472008-02-04 22:29:50 -0800176 */
Casey Schaufler7898e1f2011-01-17 08:05:27 -0800177 rcu_read_lock();
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200178 may = smk_access_entry(subject->smk_known, object->smk_known,
179 &subject->smk_rules);
Casey Schaufler7898e1f2011-01-17 08:05:27 -0800180 rcu_read_unlock();
181
Casey Schauflerd166c802014-08-27 14:51:27 -0700182 if (may <= 0 || (request & may) != request) {
183 rc = -EACCES;
Etienne Bassetecfcc532009-04-08 20:40:06 +0200184 goto out_audit;
Casey Schauflerd166c802014-08-27 14:51:27 -0700185 }
186#ifdef CONFIG_SECURITY_SMACK_BRINGUP
187 /*
188 * Return a positive value if using bringup mode.
189 * This allows the hooks to identify checks that
190 * succeed because of "b" rules.
191 */
192 if (may & MAY_BRINGUP)
Casey Schauflerbf4b2fe2015-03-21 18:26:40 -0700193 rc = SMACK_BRINGUP_ALLOW;
Casey Schauflerd166c802014-08-27 14:51:27 -0700194#endif
Casey Schauflere114e472008-02-04 22:29:50 -0800195
Etienne Bassetecfcc532009-04-08 20:40:06 +0200196out_audit:
Casey Schauflerbf4b2fe2015-03-21 18:26:40 -0700197
198#ifdef CONFIG_SECURITY_SMACK_BRINGUP
199 if (rc < 0) {
200 if (object == smack_unconfined)
201 rc = SMACK_UNCONFINED_OBJECT;
202 if (subject == smack_unconfined)
203 rc = SMACK_UNCONFINED_SUBJECT;
204 }
205#endif
206
Etienne Bassetecfcc532009-04-08 20:40:06 +0200207#ifdef CONFIG_AUDIT
208 if (a)
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200209 smack_log(subject->smk_known, object->smk_known,
210 request, rc, a);
Etienne Bassetecfcc532009-04-08 20:40:06 +0200211#endif
Casey Schauflerd166c802014-08-27 14:51:27 -0700212
Etienne Bassetecfcc532009-04-08 20:40:06 +0200213 return rc;
Casey Schauflere114e472008-02-04 22:29:50 -0800214}
215
216/**
Lukasz Pawelczyk959e6c72014-03-11 17:07:04 +0100217 * smk_tskacc - determine if a task has a specific access to an object
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200218 * @tsp: a pointer to the subject's task
219 * @obj_known: a pointer to the object's label entry
Randy Dunlap251a2a92009-02-18 11:42:33 -0800220 * @mode: the access requested, in "MAY" format
Etienne Bassetecfcc532009-04-08 20:40:06 +0200221 * @a : common audit data
Casey Schauflere114e472008-02-04 22:29:50 -0800222 *
Lukasz Pawelczyk959e6c72014-03-11 17:07:04 +0100223 * This function checks the subject task's label/object label pair
Casey Schauflere114e472008-02-04 22:29:50 -0800224 * in the access rule list and returns 0 if the access is permitted,
Lukasz Pawelczyk959e6c72014-03-11 17:07:04 +0100225 * non zero otherwise. It allows that the task may have the capability
Casey Schauflere114e472008-02-04 22:29:50 -0800226 * to override the rules.
227 */
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200228int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
Lukasz Pawelczyk959e6c72014-03-11 17:07:04 +0100229 u32 mode, struct smk_audit_info *a)
Casey Schauflere114e472008-02-04 22:29:50 -0800230{
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200231 struct smack_known *sbj_known = smk_of_task(tsp);
Casey Schaufler7898e1f2011-01-17 08:05:27 -0800232 int may;
Casey Schauflere114e472008-02-04 22:29:50 -0800233 int rc;
234
Casey Schaufler7898e1f2011-01-17 08:05:27 -0800235 /*
236 * Check the global rule list
237 */
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200238 rc = smk_access(sbj_known, obj_known, mode, NULL);
Casey Schauflerd166c802014-08-27 14:51:27 -0700239 if (rc >= 0) {
Casey Schaufler7898e1f2011-01-17 08:05:27 -0800240 /*
241 * If there is an entry in the task's rule list
242 * it can further restrict access.
243 */
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200244 may = smk_access_entry(sbj_known->smk_known,
245 obj_known->smk_known,
246 &tsp->smk_rules);
Casey Schaufler7898e1f2011-01-17 08:05:27 -0800247 if (may < 0)
248 goto out_audit;
249 if ((mode & may) == mode)
250 goto out_audit;
251 rc = -EACCES;
252 }
Casey Schauflere114e472008-02-04 22:29:50 -0800253
Casey Schaufler15446232008-07-30 15:37:11 -0700254 /*
Casey Schaufler1880eff2012-06-05 15:28:30 -0700255 * Allow for priviliged to override policy.
Casey Schaufler15446232008-07-30 15:37:11 -0700256 */
Casey Schaufler1880eff2012-06-05 15:28:30 -0700257 if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
Casey Schaufler7898e1f2011-01-17 08:05:27 -0800258 rc = 0;
Casey Schauflere114e472008-02-04 22:29:50 -0800259
Etienne Bassetecfcc532009-04-08 20:40:06 +0200260out_audit:
261#ifdef CONFIG_AUDIT
262 if (a)
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200263 smack_log(sbj_known->smk_known, obj_known->smk_known,
264 mode, rc, a);
Etienne Bassetecfcc532009-04-08 20:40:06 +0200265#endif
Casey Schauflere114e472008-02-04 22:29:50 -0800266 return rc;
267}
268
Lukasz Pawelczyk959e6c72014-03-11 17:07:04 +0100269/**
270 * smk_curacc - determine if current has a specific access to an object
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200271 * @obj_known: a pointer to the object's Smack label entry
Lukasz Pawelczyk959e6c72014-03-11 17:07:04 +0100272 * @mode: the access requested, in "MAY" format
273 * @a : common audit data
274 *
275 * This function checks the current subject label/object label pair
276 * in the access rule list and returns 0 if the access is permitted,
277 * non zero otherwise. It allows that current may have the capability
278 * to override the rules.
279 */
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200280int smk_curacc(struct smack_known *obj_known,
281 u32 mode, struct smk_audit_info *a)
Lukasz Pawelczyk959e6c72014-03-11 17:07:04 +0100282{
283 struct task_smack *tsp = current_security();
284
Lukasz Pawelczyk21c7eae2014-08-29 17:02:55 +0200285 return smk_tskacc(tsp, obj_known, mode, a);
Lukasz Pawelczyk959e6c72014-03-11 17:07:04 +0100286}
287
Etienne Bassetecfcc532009-04-08 20:40:06 +0200288#ifdef CONFIG_AUDIT
289/**
290 * smack_str_from_perm : helper to transalate an int to a
291 * readable string
292 * @string : the string to fill
293 * @access : the int
294 *
295 */
296static inline void smack_str_from_perm(char *string, int access)
297{
298 int i = 0;
Casey Schauflerc0ab6e52013-10-11 18:06:39 -0700299
Etienne Bassetecfcc532009-04-08 20:40:06 +0200300 if (access & MAY_READ)
301 string[i++] = 'r';
302 if (access & MAY_WRITE)
303 string[i++] = 'w';
304 if (access & MAY_EXEC)
305 string[i++] = 'x';
306 if (access & MAY_APPEND)
307 string[i++] = 'a';
Rafal Krypaa87d79a2012-11-27 16:29:07 +0100308 if (access & MAY_TRANSMUTE)
309 string[i++] = 't';
Casey Schauflerc0ab6e52013-10-11 18:06:39 -0700310 if (access & MAY_LOCK)
311 string[i++] = 'l';
Etienne Bassetecfcc532009-04-08 20:40:06 +0200312 string[i] = '\0';
313}
314/**
315 * smack_log_callback - SMACK specific information
316 * will be called by generic audit code
317 * @ab : the audit_buffer
318 * @a : audit_data
319 *
320 */
321static void smack_log_callback(struct audit_buffer *ab, void *a)
322{
323 struct common_audit_data *ad = a;
Eric Paris3b3b0e42012-04-03 09:37:02 -0700324 struct smack_audit_data *sad = ad->smack_audit_data;
Thomas Liued5215a2009-07-09 10:00:29 -0400325 audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
Eric Paris3b3b0e42012-04-03 09:37:02 -0700326 ad->smack_audit_data->function,
Etienne Bassetecfcc532009-04-08 20:40:06 +0200327 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);
Lukasz Pawelczyk66867812014-03-11 17:07:06 +0100332 if (sad->request[0] == '\0')
333 audit_log_format(ab, " labels_differ");
334 else
335 audit_log_format(ab, " requested=%s", sad->request);
Etienne Bassetecfcc532009-04-08 20:40:06 +0200336}
337
338/**
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
345 *
346 * Audit the granting or denial of permissions in accordance
347 * with the policy.
348 */
349void smack_log(char *subject_label, char *object_label, int request,
350 int result, struct smk_audit_info *ad)
351{
Casey Schauflerbf4b2fe2015-03-21 18:26:40 -0700352#ifdef CONFIG_SECURITY_SMACK_BRINGUP
353 char request_buffer[SMK_NUM_ACCESS_TYPE + 5];
354#else
Etienne Bassetecfcc532009-04-08 20:40:06 +0200355 char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
Casey Schauflerbf4b2fe2015-03-21 18:26:40 -0700356#endif
Etienne Bassetecfcc532009-04-08 20:40:06 +0200357 struct smack_audit_data *sad;
358 struct common_audit_data *a = &ad->a;
359
360 /* check if we have to log the current event */
Casey Schauflerbf4b2fe2015-03-21 18:26:40 -0700361 if (result < 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
Etienne Bassetecfcc532009-04-08 20:40:06 +0200362 return;
363 if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
364 return;
365
Eric Paris3b3b0e42012-04-03 09:37:02 -0700366 sad = a->smack_audit_data;
367
368 if (sad->function == NULL)
369 sad->function = "unknown";
Etienne Bassetecfcc532009-04-08 20:40:06 +0200370
371 /* end preparing the audit data */
Etienne Bassetecfcc532009-04-08 20:40:06 +0200372 smack_str_from_perm(request_buffer, request);
373 sad->subject = subject_label;
374 sad->object = object_label;
Casey Schauflerbf4b2fe2015-03-21 18:26:40 -0700375#ifdef CONFIG_SECURITY_SMACK_BRINGUP
376 /*
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.
381 */
382 if (result == SMACK_UNCONFINED_SUBJECT)
383 strcat(request_buffer, "(US)");
384 else if (result == SMACK_UNCONFINED_OBJECT)
385 strcat(request_buffer, "(UO)");
386
387 if (result > 0)
388 result = 0;
389#endif
Etienne Bassetecfcc532009-04-08 20:40:06 +0200390 sad->request = request_buffer;
391 sad->result = result;
Etienne Bassetecfcc532009-04-08 20:40:06 +0200392
Linus Torvaldsb61c37f2012-04-02 15:48:12 -0700393 common_lsm_audit(a, smack_log_callback, NULL);
Etienne Bassetecfcc532009-04-08 20:40:06 +0200394}
395#else /* #ifdef CONFIG_AUDIT */
396void smack_log(char *subject_label, char *object_label, int request,
397 int result, struct smk_audit_info *ad)
398{
399}
400#endif
401
Casey Schauflerf7112e62012-05-06 15:22:02 -0700402DEFINE_MUTEX(smack_known_lock);
Casey Schauflere114e472008-02-04 22:29:50 -0800403
Tomasz Stanislawski4d7cf4a2013-06-11 14:55:13 +0200404struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
405
406/**
407 * smk_insert_entry - insert a smack label into a hash map,
408 *
409 * this function must be called under smack_known_lock
410 */
411void smk_insert_entry(struct smack_known *skp)
412{
413 unsigned int hash;
414 struct hlist_head *head;
415
Linus Torvalds8387ff22016-06-10 07:51:30 -0700416 hash = full_name_hash(NULL, skp->smk_known, strlen(skp->smk_known));
Tomasz Stanislawski4d7cf4a2013-06-11 14:55:13 +0200417 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
418
419 hlist_add_head_rcu(&skp->smk_hashed, head);
420 list_add_rcu(&skp->list, &smack_known_list);
421}
422
Casey Schauflere114e472008-02-04 22:29:50 -0800423/**
Casey Schaufler272cd7a2011-09-20 12:24:36 -0700424 * smk_find_entry - find a label on the list, return the list entry
425 * @string: a text string that might be a Smack label
426 *
427 * Returns a pointer to the entry in the label list that
Lukasz Pawelczyke774ad62015-04-20 17:12:54 +0200428 * matches the passed string or NULL if not found.
Casey Schaufler272cd7a2011-09-20 12:24:36 -0700429 */
430struct smack_known *smk_find_entry(const char *string)
431{
Tomasz Stanislawski4d7cf4a2013-06-11 14:55:13 +0200432 unsigned int hash;
433 struct hlist_head *head;
Casey Schaufler272cd7a2011-09-20 12:24:36 -0700434 struct smack_known *skp;
435
Linus Torvalds8387ff22016-06-10 07:51:30 -0700436 hash = full_name_hash(NULL, string, strlen(string));
Tomasz Stanislawski4d7cf4a2013-06-11 14:55:13 +0200437 head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
438
439 hlist_for_each_entry_rcu(skp, head, smk_hashed)
Casey Schauflerf7112e62012-05-06 15:22:02 -0700440 if (strcmp(skp->smk_known, string) == 0)
Casey Schaufler272cd7a2011-09-20 12:24:36 -0700441 return skp;
Casey Schaufler272cd7a2011-09-20 12:24:36 -0700442
443 return NULL;
444}
445
446/**
Jarkko Sakkinen0e94ae12011-10-18 21:21:36 +0300447 * smk_parse_smack - parse smack label from a text string
448 * @string: a text string that might contain a Smack label
Casey Schauflere114e472008-02-04 22:29:50 -0800449 * @len: the maximum size, or zero if it is NULL terminated.
Casey Schauflerf7112e62012-05-06 15:22:02 -0700450 *
Lukasz Pawelczyke774ad62015-04-20 17:12:54 +0200451 * Returns a pointer to the clean label or an error code.
Casey Schauflere114e472008-02-04 22:29:50 -0800452 */
Casey Schauflerf7112e62012-05-06 15:22:02 -0700453char *smk_parse_smack(const char *string, int len)
Casey Schauflere114e472008-02-04 22:29:50 -0800454{
Casey Schauflerf7112e62012-05-06 15:22:02 -0700455 char *smack;
Casey Schauflere114e472008-02-04 22:29:50 -0800456 int i;
457
Casey Schauflerf7112e62012-05-06 15:22:02 -0700458 if (len <= 0)
459 len = strlen(string) + 1;
Casey Schauflere114e472008-02-04 22:29:50 -0800460
Casey Schauflerf7112e62012-05-06 15:22:02 -0700461 /*
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
465 */
466 if (string[0] == '-')
Lukasz Pawelczyke774ad62015-04-20 17:12:54 +0200467 return ERR_PTR(-EINVAL);
Casey Schauflerf7112e62012-05-06 15:22:02 -0700468
469 for (i = 0; i < len; i++)
470 if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
471 string[i] == '"' || string[i] == '\\' || string[i] == '\'')
472 break;
473
474 if (i == 0 || i >= SMK_LONGLABEL)
Lukasz Pawelczyke774ad62015-04-20 17:12:54 +0200475 return ERR_PTR(-EINVAL);
Casey Schauflerf7112e62012-05-06 15:22:02 -0700476
477 smack = kzalloc(i + 1, GFP_KERNEL);
Lukasz Pawelczyke774ad62015-04-20 17:12:54 +0200478 if (smack == NULL)
479 return ERR_PTR(-ENOMEM);
480
481 strncpy(smack, string, i);
Andrey Ryabinin5c1b6622014-11-08 17:48:05 +0300482
Casey Schauflerf7112e62012-05-06 15:22:02 -0700483 return smack;
484}
485
486/**
487 * smk_netlbl_mls - convert a catset to netlabel mls categories
488 * @catset: the Smack categories
489 * @sap: where to put the netlabel categories
490 *
491 * Allocates and fills attr.mls
492 * Returns 0 on success, error code on failure.
493 */
494int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
495 int len)
496{
497 unsigned char *cp;
498 unsigned char m;
499 int cat;
500 int rc;
501 int byte;
502
503 sap->flags |= NETLBL_SECATTR_MLS_CAT;
504 sap->attr.mls.lvl = level;
Paul Moore4b8feff2014-08-01 11:17:17 -0400505 sap->attr.mls.cat = NULL;
Casey Schauflerf7112e62012-05-06 15:22:02 -0700506
507 for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
508 for (m = 0x80; m != 0; m >>= 1, cat++) {
509 if ((m & *cp) == 0)
510 continue;
Paul Moore4fbe63d2014-08-01 11:17:37 -0400511 rc = netlbl_catmap_setbit(&sap->attr.mls.cat,
512 cat, GFP_ATOMIC);
Casey Schauflerf7112e62012-05-06 15:22:02 -0700513 if (rc < 0) {
Paul Moore4fbe63d2014-08-01 11:17:37 -0400514 netlbl_catmap_free(sap->attr.mls.cat);
Casey Schauflerf7112e62012-05-06 15:22:02 -0700515 return rc;
516 }
517 }
518
519 return 0;
Jarkko Sakkinen0e94ae12011-10-18 21:21:36 +0300520}
Casey Schauflere114e472008-02-04 22:29:50 -0800521
Jarkko Sakkinen0e94ae12011-10-18 21:21:36 +0300522/**
523 * smk_import_entry - import a label, return the list entry
524 * @string: a text string that might be a Smack label
525 * @len: the maximum size, or zero if it is NULL terminated.
526 *
527 * Returns a pointer to the entry in the label list that
Lukasz Pawelczyke774ad62015-04-20 17:12:54 +0200528 * matches the passed string, adding it if necessary,
529 * or an error code.
Jarkko Sakkinen0e94ae12011-10-18 21:21:36 +0300530 */
531struct smack_known *smk_import_entry(const char *string, int len)
532{
533 struct smack_known *skp;
Casey Schauflerf7112e62012-05-06 15:22:02 -0700534 char *smack;
535 int slen;
536 int rc;
Jarkko Sakkinen0e94ae12011-10-18 21:21:36 +0300537
Casey Schauflerf7112e62012-05-06 15:22:02 -0700538 smack = smk_parse_smack(string, len);
Lukasz Pawelczyke774ad62015-04-20 17:12:54 +0200539 if (IS_ERR(smack))
540 return ERR_CAST(smack);
Casey Schauflere114e472008-02-04 22:29:50 -0800541
542 mutex_lock(&smack_known_lock);
543
Casey Schaufler272cd7a2011-09-20 12:24:36 -0700544 skp = smk_find_entry(smack);
Casey Schauflerf7112e62012-05-06 15:22:02 -0700545 if (skp != NULL)
546 goto freeout;
Casey Schauflere114e472008-02-04 22:29:50 -0800547
Casey Schauflerf7112e62012-05-06 15:22:02 -0700548 skp = kzalloc(sizeof(*skp), GFP_KERNEL);
Lukasz Pawelczyke774ad62015-04-20 17:12:54 +0200549 if (skp == NULL) {
550 skp = ERR_PTR(-ENOMEM);
Casey Schauflerf7112e62012-05-06 15:22:02 -0700551 goto freeout;
Lukasz Pawelczyke774ad62015-04-20 17:12:54 +0200552 }
Casey Schauflerf7112e62012-05-06 15:22:02 -0700553
554 skp->smk_known = smack;
555 skp->smk_secid = smack_next_secid++;
556 skp->smk_netlabel.domain = skp->smk_known;
557 skp->smk_netlabel.flags =
558 NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
559 /*
560 * If direct labeling works use it.
561 * Otherwise use mapped labeling.
562 */
563 slen = strlen(smack);
564 if (slen < SMK_CIPSOLEN)
565 rc = smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
566 &skp->smk_netlabel, slen);
567 else
568 rc = smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
569 &skp->smk_netlabel, sizeof(skp->smk_secid));
570
571 if (rc >= 0) {
572 INIT_LIST_HEAD(&skp->smk_rules);
573 mutex_init(&skp->smk_rules_lock);
574 /*
575 * Make sure that the entry is actually
576 * filled before putting it on the list.
577 */
Tomasz Stanislawski4d7cf4a2013-06-11 14:55:13 +0200578 smk_insert_entry(skp);
Casey Schauflerf7112e62012-05-06 15:22:02 -0700579 goto unlockout;
Casey Schauflere114e472008-02-04 22:29:50 -0800580 }
Casey Schauflerf7112e62012-05-06 15:22:02 -0700581 /*
582 * smk_netlbl_mls failed.
583 */
584 kfree(skp);
Lukasz Pawelczyke774ad62015-04-20 17:12:54 +0200585 skp = ERR_PTR(rc);
Casey Schauflerf7112e62012-05-06 15:22:02 -0700586freeout:
587 kfree(smack);
588unlockout:
Casey Schauflere114e472008-02-04 22:29:50 -0800589 mutex_unlock(&smack_known_lock);
590
591 return skp;
592}
593
594/**
Casey Schauflere114e472008-02-04 22:29:50 -0800595 * smack_from_secid - find the Smack label associated with a secid
596 * @secid: an integer that might be associated with a Smack label
597 *
Casey Schaufler2f823ff2013-05-22 18:43:03 -0700598 * Returns a pointer to the appropriate Smack label entry if there is one,
Casey Schauflere114e472008-02-04 22:29:50 -0800599 * otherwise a pointer to the invalid Smack label.
600 */
Casey Schaufler2f823ff2013-05-22 18:43:03 -0700601struct smack_known *smack_from_secid(const u32 secid)
Casey Schauflere114e472008-02-04 22:29:50 -0800602{
603 struct smack_known *skp;
604
Etienne Basset7198e2e2009-03-24 20:53:24 +0100605 rcu_read_lock();
606 list_for_each_entry_rcu(skp, &smack_known_list, list) {
607 if (skp->smk_secid == secid) {
608 rcu_read_unlock();
Casey Schaufler2f823ff2013-05-22 18:43:03 -0700609 return skp;
Etienne Basset7198e2e2009-03-24 20:53:24 +0100610 }
611 }
Casey Schauflere114e472008-02-04 22:29:50 -0800612
613 /*
614 * If we got this far someone asked for the translation
615 * of a secid that is not on the list.
616 */
Etienne Basset7198e2e2009-03-24 20:53:24 +0100617 rcu_read_unlock();
Casey Schaufler2f823ff2013-05-22 18:43:03 -0700618 return &smack_known_invalid;
Casey Schauflere114e472008-02-04 22:29:50 -0800619}
Rafal Krypac0d77c82015-06-02 11:23:48 +0200620
621/*
622 * Unless a process is running with one of these labels
623 * even having CAP_MAC_OVERRIDE isn't enough to grant
624 * privilege to violate MAC policy. If no labels are
625 * designated (the empty list case) capabilities apply to
626 * everyone.
627 */
628LIST_HEAD(smack_onlycap_list);
629DEFINE_MUTEX(smack_onlycap_lock);
630
631/*
632 * Is the task privileged and allowed to be privileged
633 * by the onlycap rule.
634 *
635 * Returns 1 if the task is allowed to be privileged, 0 if it's not.
636 */
637int smack_privileged(int cap)
638{
639 struct smack_known *skp = smk_of_current();
Zbigniew Jasinski38416e52015-10-19 18:23:53 +0200640 struct smack_known_list_elem *sklep;
Rafal Krypac0d77c82015-06-02 11:23:48 +0200641
Roman Kubiak41a2d572015-08-10 16:54:25 +0200642 /*
643 * All kernel tasks are privileged
644 */
645 if (unlikely(current->flags & PF_KTHREAD))
646 return 1;
647
Rafal Krypac0d77c82015-06-02 11:23:48 +0200648 if (!capable(cap))
649 return 0;
650
651 rcu_read_lock();
652 if (list_empty(&smack_onlycap_list)) {
653 rcu_read_unlock();
654 return 1;
655 }
656
Zbigniew Jasinski38416e52015-10-19 18:23:53 +0200657 list_for_each_entry_rcu(sklep, &smack_onlycap_list, list) {
658 if (sklep->smk_label == skp) {
Rafal Krypac0d77c82015-06-02 11:23:48 +0200659 rcu_read_unlock();
660 return 1;
661 }
662 }
663 rcu_read_unlock();
664
665 return 0;
666}