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 
32 extern 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  */
55 enum 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 
62 enum 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 
77 struct 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  */
85 struct 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  */
98 struct 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  */
130 struct 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  */
147 struct 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 
154 struct 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  */
198 struct 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 
227 extern struct aa_namespace *root_ns;
228 extern enum profile_mode aa_g_profile_mode;
229 
230 void aa_add_profile(struct aa_policy *common, struct aa_profile *profile);
231 
232 bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view);
233 const char *aa_ns_name(struct aa_namespace *parent, struct aa_namespace *child);
234 int aa_alloc_root_ns(void);
235 void aa_free_root_ns(void);
236 void aa_free_namespace_kref(struct kref *kref);
237 
238 struct aa_namespace *aa_find_namespace(struct aa_namespace *root,
239 				       const char *name);
240 
241 
242 void aa_free_replacedby_kref(struct kref *kref);
243 struct aa_profile *aa_alloc_profile(const char *name);
244 struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat);
245 void aa_free_profile(struct aa_profile *profile);
246 void aa_free_profile_kref(struct kref *kref);
247 struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name);
248 struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *name);
249 struct aa_profile *aa_match_profile(struct aa_namespace *ns, const char *name);
250 
251 ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace);
252 ssize_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 
260 static 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  */
273 static 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  */
288 static 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  */
303 static 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  */
324 static 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  */
339 static inline void aa_put_profile(struct aa_profile *p)
340 {
341 	if (p)
342 		kref_put(&p->count, aa_free_profile_kref);
343 }
344 
345 static 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 
353 static 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 */
360 static 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  */
378 static 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  */
392 static inline void aa_put_namespace(struct aa_namespace *ns)
393 {
394 	if (ns)
395 		aa_put_profile(ns->unconfined);
396 }
397 
398 static 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 
406 bool aa_may_manage_policy(int op);
407 
408 #endif /* __AA_POLICY_H */
409