1/*
2 * AppArmor security module
3 *
4 * This file contains AppArmor policy definitions.
5 *
6 * Copyright (C) 1998-2008 Novell/SUSE
7 * Copyright 2009-2010 Canonical Ltd.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation, version 2 of the
12 * License.
13 */
14
15#ifndef __AA_POLICY_H
16#define __AA_POLICY_H
17
18#include <linux/capability.h>
19#include <linux/cred.h>
20#include <linux/kref.h>
21#include <linux/sched.h>
22#include <linux/slab.h>
23#include <linux/socket.h>
24
25#include "apparmor.h"
26#include "audit.h"
27#include "capability.h"
28#include "domain.h"
29#include "file.h"
30#include "resource.h"
31
32extern const char *const aa_profile_mode_names[];
33#define APPARMOR_MODE_NAMES_MAX_INDEX 4
34
35#define PROFILE_MODE(_profile, _mode)		\
36	((aa_g_profile_mode == (_mode)) ||	\
37	 ((_profile)->mode == (_mode)))
38
39#define COMPLAIN_MODE(_profile)	PROFILE_MODE((_profile), APPARMOR_COMPLAIN)
40
41#define KILL_MODE(_profile) PROFILE_MODE((_profile), APPARMOR_KILL)
42
43#define PROFILE_IS_HAT(_profile) ((_profile)->flags & PFLAG_HAT)
44
45#define PROFILE_INVALID(_profile) ((_profile)->flags & PFLAG_INVALID)
46
47#define on_list_rcu(X) (!list_empty(X) && (X)->prev != LIST_POISON2)
48
49/*
50 * FIXME: currently need a clean way to replace and remove profiles as a
51 * set.  It should be done at the namespace level.
52 * Either, with a set of profiles loaded at the namespace level or via
53 * a mark and remove marked interface.
54 */
55enum profile_mode {
56	APPARMOR_ENFORCE,	/* enforce access rules */
57	APPARMOR_COMPLAIN,	/* allow and log access violations */
58	APPARMOR_KILL,		/* kill task on access violation */
59	APPARMOR_UNCONFINED,	/* profile set to unconfined */
60};
61
62enum profile_flags {
63	PFLAG_HAT = 1,			/* profile is a hat */
64	PFLAG_NULL = 4,			/* profile is null learning profile */
65	PFLAG_IX_ON_NAME_ERROR = 8,	/* fallback to ix on name lookup fail */
66	PFLAG_IMMUTABLE = 0x10,		/* don't allow changes/replacement */
67	PFLAG_USER_DEFINED = 0x20,	/* user based profile - lower privs */
68	PFLAG_NO_LIST_REF = 0x40,	/* list doesn't keep profile ref */
69	PFLAG_OLD_NULL_TRANS = 0x100,	/* use // as the null transition */
70	PFLAG_INVALID = 0x200,		/* profile replaced/removed */
71	PFLAG_NS_COUNT = 0x400,		/* carries NS ref count */
72
73	/* These flags must correspond with PATH_flags */
74	PFLAG_MEDIATE_DELETED = 0x10000, /* mediate instead delegate deleted */
75};
76
77struct aa_profile;
78
79/* struct aa_policy - common part of both namespaces and profiles
80 * @name: name of the object
81 * @hname - The hierarchical name
82 * @list: list policy object is on
83 * @profiles: head of the profiles list contained in the object
84 */
85struct aa_policy {
86	char *name;
87	char *hname;
88	struct list_head list;
89	struct list_head profiles;
90};
91
92/* struct aa_ns_acct - accounting of profiles in namespace
93 * @max_size: maximum space allowed for all profiles in namespace
94 * @max_count: maximum number of profiles that can be in this namespace
95 * @size: current size of profiles
96 * @count: current count of profiles (includes null profiles)
97 */
98struct aa_ns_acct {
99	int max_size;
100	int max_count;
101	int size;
102	int count;
103};
104
105/* struct aa_namespace - namespace for a set of profiles
106 * @base: common policy
107 * @parent: parent of namespace
108 * @lock: lock for modifying the object
109 * @acct: accounting for the namespace
110 * @unconfined: special unconfined profile for the namespace
111 * @sub_ns: list of namespaces under the current namespace.
112 * @uniq_null: uniq value used for null learning profiles
113 * @uniq_id: a unique id count for the profiles in the namespace
114 * @dents: dentries for the namespaces file entries in apparmorfs
115 *
116 * An aa_namespace defines the set profiles that are searched to determine
117 * which profile to attach to a task.  Profiles can not be shared between
118 * aa_namespaces and profile names within a namespace are guaranteed to be
119 * unique.  When profiles in separate namespaces have the same name they
120 * are NOT considered to be equivalent.
121 *
122 * Namespaces are hierarchical and only namespaces and profiles below the
123 * current namespace are visible.
124 *
125 * Namespace names must be unique and can not contain the characters :/\0
126 *
127 * FIXME TODO: add vserver support of namespaces (can it all be done in
128 *             userspace?)
129 */
130struct aa_namespace {
131	struct aa_policy base;
132	struct aa_namespace *parent;
133	struct mutex lock;
134	struct aa_ns_acct acct;
135	struct aa_profile *unconfined;
136	struct list_head sub_ns;
137	atomic_t uniq_null;
138	long uniq_id;
139
140	struct dentry *dents[AAFS_NS_SIZEOF];
141};
142
143/* struct aa_policydb - match engine for a policy
144 * dfa: dfa pattern match
145 * start: set of start states for the different classes of data
146 */
147struct aa_policydb {
148	/* Generic policy DFA specific rule types will be subsections of it */
149	struct aa_dfa *dfa;
150	unsigned int start[AA_CLASS_LAST + 1];
151
152};
153
154struct aa_replacedby {
155	struct kref count;
156	struct aa_profile __rcu *profile;
157};
158
159
160/* struct aa_profile - basic confinement data
161 * @base - base components of the profile (name, refcount, lists, lock ...)
162 * @count: reference count of the obj
163 * @rcu: rcu head used when removing from @list
164 * @parent: parent of profile
165 * @ns: namespace the profile is in
166 * @replacedby: is set to the profile that replaced this profile
167 * @rename: optional profile name that this profile renamed
168 * @attach: human readable attachment string
169 * @xmatch: optional extended matching for unconfined executables names
170 * @xmatch_len: xmatch prefix len, used to determine xmatch priority
171 * @audit: the auditing mode of the profile
172 * @mode: the enforcement mode of the profile
173 * @flags: flags controlling profile behavior
174 * @path_flags: flags controlling path generation behavior
175 * @size: the memory consumed by this profiles rules
176 * @policy: general match rules governing policy
177 * @file: The set of rules governing basic file access and domain transitions
178 * @caps: capabilities for the profile
179 * @rlimits: rlimits for the profile
180 *
181 * @dents: dentries for the profiles file entries in apparmorfs
182 * @dirname: name of the profile dir in apparmorfs
183 *
184 * The AppArmor profile contains the basic confinement data.  Each profile
185 * has a name, and exists in a namespace.  The @name and @exec_match are
186 * used to determine profile attachment against unconfined tasks.  All other
187 * attachments are determined by profile X transition rules.
188 *
189 * The @replacedby struct is write protected by the profile lock.
190 *
191 * Profiles have a hierarchy where hats and children profiles keep
192 * a reference to their parent.
193 *
194 * Profile names can not begin with a : and can not contain the \0
195 * character.  If a profile name begins with / it will be considered when
196 * determining profile attachment on "unconfined" tasks.
197 */
198struct aa_profile {
199	struct aa_policy base;
200	struct kref count;
201	struct rcu_head rcu;
202	struct aa_profile __rcu *parent;
203
204	struct aa_namespace *ns;
205	struct aa_replacedby *replacedby;
206	const char *rename;
207
208	const char *attach;
209	struct aa_dfa *xmatch;
210	int xmatch_len;
211	enum audit_mode audit;
212	long mode;
213	long flags;
214	u32 path_flags;
215	int size;
216
217	struct aa_policydb policy;
218	struct aa_file_rules file;
219	struct aa_caps caps;
220	struct aa_rlimit rlimits;
221
222	unsigned char *hash;
223	char *dirname;
224	struct dentry *dents[AAFS_PROF_SIZEOF];
225};
226
227extern struct aa_namespace *root_ns;
228extern enum profile_mode aa_g_profile_mode;
229
230void aa_add_profile(struct aa_policy *common, struct aa_profile *profile);
231
232bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view);
233const char *aa_ns_name(struct aa_namespace *parent, struct aa_namespace *child);
234int aa_alloc_root_ns(void);
235void aa_free_root_ns(void);
236void aa_free_namespace_kref(struct kref *kref);
237
238struct aa_namespace *aa_find_namespace(struct aa_namespace *root,
239				       const char *name);
240
241
242void aa_free_replacedby_kref(struct kref *kref);
243struct aa_profile *aa_alloc_profile(const char *name);
244struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat);
245void aa_free_profile(struct aa_profile *profile);
246void aa_free_profile_kref(struct kref *kref);
247struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name);
248struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *name);
249struct aa_profile *aa_match_profile(struct aa_namespace *ns, const char *name);
250
251ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace);
252ssize_t aa_remove_profiles(char *name, size_t size);
253
254#define PROF_ADD 1
255#define PROF_REPLACE 0
256
257#define unconfined(X) ((X)->mode == APPARMOR_UNCONFINED)
258
259
260static inline struct aa_profile *aa_deref_parent(struct aa_profile *p)
261{
262	return rcu_dereference_protected(p->parent,
263					 mutex_is_locked(&p->ns->lock));
264}
265
266/**
267 * aa_get_profile - increment refcount on profile @p
268 * @p: profile  (MAYBE NULL)
269 *
270 * Returns: pointer to @p if @p is NULL will return NULL
271 * Requires: @p must be held with valid refcount when called
272 */
273static inline struct aa_profile *aa_get_profile(struct aa_profile *p)
274{
275	if (p)
276		kref_get(&(p->count));
277
278	return p;
279}
280
281/**
282 * aa_get_profile_not0 - increment refcount on profile @p found via lookup
283 * @p: profile  (MAYBE NULL)
284 *
285 * Returns: pointer to @p if @p is NULL will return NULL
286 * Requires: @p must be held with valid refcount when called
287 */
288static inline struct aa_profile *aa_get_profile_not0(struct aa_profile *p)
289{
290	if (p && kref_get_not0(&p->count))
291		return p;
292
293	return NULL;
294}
295
296/**
297 * aa_get_profile_rcu - increment a refcount profile that can be replaced
298 * @p: pointer to profile that can be replaced (NOT NULL)
299 *
300 * Returns: pointer to a refcounted profile.
301 *     else NULL if no profile
302 */
303static inline struct aa_profile *aa_get_profile_rcu(struct aa_profile __rcu **p)
304{
305	struct aa_profile *c;
306
307	rcu_read_lock();
308	do {
309		c = rcu_dereference(*p);
310	} while (c && !kref_get_not0(&c->count));
311	rcu_read_unlock();
312
313	return c;
314}
315
316/**
317 * aa_get_newest_profile - find the newest version of @profile
318 * @profile: the profile to check for newer versions of
319 *
320 * Returns: refcounted newest version of @profile taking into account
321 *          replacement, renames and removals
322 *          return @profile.
323 */
324static inline struct aa_profile *aa_get_newest_profile(struct aa_profile *p)
325{
326	if (!p)
327		return NULL;
328
329	if (PROFILE_INVALID(p))
330		return aa_get_profile_rcu(&p->replacedby->profile);
331
332	return aa_get_profile(p);
333}
334
335/**
336 * aa_put_profile - decrement refcount on profile @p
337 * @p: profile  (MAYBE NULL)
338 */
339static inline void aa_put_profile(struct aa_profile *p)
340{
341	if (p)
342		kref_put(&p->count, aa_free_profile_kref);
343}
344
345static inline struct aa_replacedby *aa_get_replacedby(struct aa_replacedby *p)
346{
347	if (p)
348		kref_get(&(p->count));
349
350	return p;
351}
352
353static inline void aa_put_replacedby(struct aa_replacedby *p)
354{
355	if (p)
356		kref_put(&p->count, aa_free_replacedby_kref);
357}
358
359/* requires profile list write lock held */
360static inline void __aa_update_replacedby(struct aa_profile *orig,
361					  struct aa_profile *new)
362{
363	struct aa_profile *tmp;
364	tmp = rcu_dereference_protected(orig->replacedby->profile,
365					mutex_is_locked(&orig->ns->lock));
366	rcu_assign_pointer(orig->replacedby->profile, aa_get_profile(new));
367	orig->flags |= PFLAG_INVALID;
368	aa_put_profile(tmp);
369}
370
371/**
372 * aa_get_namespace - increment references count on @ns
373 * @ns: namespace to increment reference count of (MAYBE NULL)
374 *
375 * Returns: pointer to @ns, if @ns is NULL returns NULL
376 * Requires: @ns must be held with valid refcount when called
377 */
378static inline struct aa_namespace *aa_get_namespace(struct aa_namespace *ns)
379{
380	if (ns)
381		aa_get_profile(ns->unconfined);
382
383	return ns;
384}
385
386/**
387 * aa_put_namespace - decrement refcount on @ns
388 * @ns: namespace to put reference of
389 *
390 * Decrement reference count of @ns and if no longer in use free it
391 */
392static inline void aa_put_namespace(struct aa_namespace *ns)
393{
394	if (ns)
395		aa_put_profile(ns->unconfined);
396}
397
398static inline int AUDIT_MODE(struct aa_profile *profile)
399{
400	if (aa_g_audit != AUDIT_NORMAL)
401		return aa_g_audit;
402
403	return profile->audit;
404}
405
406bool aa_may_manage_policy(int op);
407
408#endif /* __AA_POLICY_H */
409