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/rhashtable.h>
22 #include <linux/sched.h>
23 #include <linux/slab.h>
24 #include <linux/socket.h>
25 
26 #include "apparmor.h"
27 #include "audit.h"
28 #include "capability.h"
29 #include "domain.h"
30 #include "file.h"
31 #include "lib.h"
32 #include "resource.h"
33 
34 
35 struct aa_ns;
36 
37 extern int unprivileged_userns_apparmor_policy;
38 
39 extern const char *const aa_profile_mode_names[];
40 #define APPARMOR_MODE_NAMES_MAX_INDEX 4
41 
42 #define PROFILE_MODE(_profile, _mode)		\
43 	((aa_g_profile_mode == (_mode)) ||	\
44 	 ((_profile)->mode == (_mode)))
45 
46 #define COMPLAIN_MODE(_profile)	PROFILE_MODE((_profile), APPARMOR_COMPLAIN)
47 
48 #define KILL_MODE(_profile) PROFILE_MODE((_profile), APPARMOR_KILL)
49 
50 #define PROFILE_IS_HAT(_profile) ((_profile)->flags & PFLAG_HAT)
51 
52 #define profile_is_stale(_profile) ((_profile)->flags & PFLAG_STALE)
53 
54 #define on_list_rcu(X) (!list_empty(X) && (X)->prev != LIST_POISON2)
55 
56 /*
57  * FIXME: currently need a clean way to replace and remove profiles as a
58  * set.  It should be done at the namespace level.
59  * Either, with a set of profiles loaded at the namespace level or via
60  * a mark and remove marked interface.
61  */
62 enum profile_mode {
63 	APPARMOR_ENFORCE,	/* enforce access rules */
64 	APPARMOR_COMPLAIN,	/* allow and log access violations */
65 	APPARMOR_KILL,		/* kill task on access violation */
66 	APPARMOR_UNCONFINED,	/* profile set to unconfined */
67 };
68 
69 enum profile_flags {
70 	PFLAG_HAT = 1,			/* profile is a hat */
71 	PFLAG_NULL = 4,			/* profile is null learning profile */
72 	PFLAG_IX_ON_NAME_ERROR = 8,	/* fallback to ix on name lookup fail */
73 	PFLAG_IMMUTABLE = 0x10,		/* don't allow changes/replacement */
74 	PFLAG_USER_DEFINED = 0x20,	/* user based profile - lower privs */
75 	PFLAG_NO_LIST_REF = 0x40,	/* list doesn't keep profile ref */
76 	PFLAG_OLD_NULL_TRANS = 0x100,	/* use // as the null transition */
77 	PFLAG_STALE = 0x200,		/* profile replaced/removed */
78 	PFLAG_NS_COUNT = 0x400,		/* carries NS ref count */
79 
80 	/* These flags must correspond with PATH_flags */
81 	PFLAG_MEDIATE_DELETED = 0x10000, /* mediate instead delegate deleted */
82 };
83 
84 struct aa_profile;
85 
86 /* struct aa_policydb - match engine for a policy
87  * dfa: dfa pattern match
88  * start: set of start states for the different classes of data
89  */
90 struct aa_policydb {
91 	/* Generic policy DFA specific rule types will be subsections of it */
92 	struct aa_dfa *dfa;
93 	unsigned int start[AA_CLASS_LAST + 1];
94 
95 };
96 
97 struct aa_proxy {
98 	struct kref count;
99 	struct aa_profile __rcu *profile;
100 };
101 
102 /* struct aa_data - generic data structure
103  * key: name for retrieving this data
104  * size: size of data in bytes
105  * data: binary data
106  * head: reserved for rhashtable
107  */
108 struct aa_data {
109 	char *key;
110 	u32 size;
111 	char *data;
112 	struct rhash_head head;
113 };
114 
115 
116 /* struct aa_profile - basic confinement data
117  * @base - base components of the profile (name, refcount, lists, lock ...)
118  * @count: reference count of the obj
119  * @rcu: rcu head used when removing from @list
120  * @parent: parent of profile
121  * @ns: namespace the profile is in
122  * @proxy: is set to the profile that replaced this profile
123  * @rename: optional profile name that this profile renamed
124  * @attach: human readable attachment string
125  * @xmatch: optional extended matching for unconfined executables names
126  * @xmatch_len: xmatch prefix len, used to determine xmatch priority
127  * @audit: the auditing mode of the profile
128  * @mode: the enforcement mode of the profile
129  * @flags: flags controlling profile behavior
130  * @path_flags: flags controlling path generation behavior
131  * @size: the memory consumed by this profiles rules
132  * @policy: general match rules governing policy
133  * @file: The set of rules governing basic file access and domain transitions
134  * @caps: capabilities for the profile
135  * @rlimits: rlimits for the profile
136  *
137  * @dents: dentries for the profiles file entries in apparmorfs
138  * @dirname: name of the profile dir in apparmorfs
139  * @data: hashtable for free-form policy aa_data
140  *
141  * The AppArmor profile contains the basic confinement data.  Each profile
142  * has a name, and exists in a namespace.  The @name and @exec_match are
143  * used to determine profile attachment against unconfined tasks.  All other
144  * attachments are determined by profile X transition rules.
145  *
146  * The @proxy struct is write protected by the profile lock.
147  *
148  * Profiles have a hierarchy where hats and children profiles keep
149  * a reference to their parent.
150  *
151  * Profile names can not begin with a : and can not contain the \0
152  * character.  If a profile name begins with / it will be considered when
153  * determining profile attachment on "unconfined" tasks.
154  */
155 struct aa_profile {
156 	struct aa_policy base;
157 	struct kref count;
158 	struct rcu_head rcu;
159 	struct aa_profile __rcu *parent;
160 
161 	struct aa_ns *ns;
162 	struct aa_proxy *proxy;
163 	const char *rename;
164 
165 	const char *attach;
166 	struct aa_dfa *xmatch;
167 	int xmatch_len;
168 	enum audit_mode audit;
169 	long mode;
170 	long flags;
171 	u32 path_flags;
172 	int size;
173 
174 	struct aa_policydb policy;
175 	struct aa_file_rules file;
176 	struct aa_caps caps;
177 	struct aa_rlimit rlimits;
178 
179 	struct aa_loaddata *rawdata;
180 	unsigned char *hash;
181 	char *dirname;
182 	struct dentry *dents[AAFS_PROF_SIZEOF];
183 	struct rhashtable *data;
184 };
185 
186 extern enum profile_mode aa_g_profile_mode;
187 
188 void __aa_update_proxy(struct aa_profile *orig, struct aa_profile *new);
189 
190 void aa_add_profile(struct aa_policy *common, struct aa_profile *profile);
191 
192 
193 void aa_free_proxy_kref(struct kref *kref);
194 struct aa_profile *aa_alloc_profile(const char *name, gfp_t gfp);
195 struct aa_profile *aa_new_null_profile(struct aa_profile *parent, bool hat,
196 				       const char *base, gfp_t gfp);
197 void aa_free_profile(struct aa_profile *profile);
198 void aa_free_profile_kref(struct kref *kref);
199 struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name);
200 struct aa_profile *aa_lookupn_profile(struct aa_ns *ns, const char *hname,
201 				      size_t n);
202 struct aa_profile *aa_lookup_profile(struct aa_ns *ns, const char *name);
203 struct aa_profile *aa_fqlookupn_profile(struct aa_profile *base,
204 					const char *fqname, size_t n);
205 struct aa_profile *aa_match_profile(struct aa_ns *ns, const char *name);
206 
207 ssize_t aa_replace_profiles(struct aa_ns *view, struct aa_profile *profile,
208 			    bool noreplace, struct aa_loaddata *udata);
209 ssize_t aa_remove_profiles(struct aa_ns *view, struct aa_profile *profile,
210 			    char *name, size_t size);
211 void __aa_profile_list_release(struct list_head *head);
212 
213 #define PROF_ADD 1
214 #define PROF_REPLACE 0
215 
216 #define unconfined(X) ((X)->mode == APPARMOR_UNCONFINED)
217 
218 
219 /**
220  * aa_get_profile - increment refcount on profile @p
221  * @p: profile  (MAYBE NULL)
222  *
223  * Returns: pointer to @p if @p is NULL will return NULL
224  * Requires: @p must be held with valid refcount when called
225  */
226 static inline struct aa_profile *aa_get_profile(struct aa_profile *p)
227 {
228 	if (p)
229 		kref_get(&(p->count));
230 
231 	return p;
232 }
233 
234 /**
235  * aa_get_profile_not0 - increment refcount on profile @p found via lookup
236  * @p: profile  (MAYBE NULL)
237  *
238  * Returns: pointer to @p if @p is NULL will return NULL
239  * Requires: @p must be held with valid refcount when called
240  */
241 static inline struct aa_profile *aa_get_profile_not0(struct aa_profile *p)
242 {
243 	if (p && kref_get_unless_zero(&p->count))
244 		return p;
245 
246 	return NULL;
247 }
248 
249 /**
250  * aa_get_profile_rcu - increment a refcount profile that can be replaced
251  * @p: pointer to profile that can be replaced (NOT NULL)
252  *
253  * Returns: pointer to a refcounted profile.
254  *     else NULL if no profile
255  */
256 static inline struct aa_profile *aa_get_profile_rcu(struct aa_profile __rcu **p)
257 {
258 	struct aa_profile *c;
259 
260 	rcu_read_lock();
261 	do {
262 		c = rcu_dereference(*p);
263 	} while (c && !kref_get_unless_zero(&c->count));
264 	rcu_read_unlock();
265 
266 	return c;
267 }
268 
269 /**
270  * aa_get_newest_profile - find the newest version of @profile
271  * @profile: the profile to check for newer versions of
272  *
273  * Returns: refcounted newest version of @profile taking into account
274  *          replacement, renames and removals
275  *          return @profile.
276  */
277 static inline struct aa_profile *aa_get_newest_profile(struct aa_profile *p)
278 {
279 	if (!p)
280 		return NULL;
281 
282 	if (profile_is_stale(p))
283 		return aa_get_profile_rcu(&p->proxy->profile);
284 
285 	return aa_get_profile(p);
286 }
287 
288 /**
289  * aa_put_profile - decrement refcount on profile @p
290  * @p: profile  (MAYBE NULL)
291  */
292 static inline void aa_put_profile(struct aa_profile *p)
293 {
294 	if (p)
295 		kref_put(&p->count, aa_free_profile_kref);
296 }
297 
298 static inline struct aa_proxy *aa_get_proxy(struct aa_proxy *p)
299 {
300 	if (p)
301 		kref_get(&(p->count));
302 
303 	return p;
304 }
305 
306 static inline void aa_put_proxy(struct aa_proxy *p)
307 {
308 	if (p)
309 		kref_put(&p->count, aa_free_proxy_kref);
310 }
311 
312 static inline int AUDIT_MODE(struct aa_profile *profile)
313 {
314 	if (aa_g_audit != AUDIT_NORMAL)
315 		return aa_g_audit;
316 
317 	return profile->audit;
318 }
319 
320 bool policy_view_capable(struct aa_ns *ns);
321 bool policy_admin_capable(struct aa_ns *ns);
322 int aa_may_manage_policy(struct aa_profile *profile, struct aa_ns *ns,
323 			 const char *op);
324 
325 #endif /* __AA_POLICY_H */
326