xref: /openbmc/linux/security/smack/smack.h (revision 4800cd83)
1 /*
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 #ifndef _SECURITY_SMACK_H
14 #define _SECURITY_SMACK_H
15 
16 #include <linux/capability.h>
17 #include <linux/spinlock.h>
18 #include <linux/security.h>
19 #include <linux/in.h>
20 #include <net/netlabel.h>
21 #include <linux/list.h>
22 #include <linux/rculist.h>
23 #include <linux/lsm_audit.h>
24 
25 /*
26  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
27  * bigger than can be used, and 24 is the next lower multiple
28  * of 8, and there are too many issues if there isn't space set
29  * aside for the terminating null byte.
30  */
31 #define SMK_MAXLEN	23
32 #define SMK_LABELLEN	(SMK_MAXLEN+1)
33 
34 struct superblock_smack {
35 	char		*smk_root;
36 	char		*smk_floor;
37 	char		*smk_hat;
38 	char		*smk_default;
39 	int		smk_initialized;
40 	spinlock_t	smk_sblock;	/* for initialization */
41 };
42 
43 struct socket_smack {
44 	char		*smk_out;			/* outbound label */
45 	char		*smk_in;			/* inbound label */
46 	char		smk_packet[SMK_LABELLEN];	/* TCP peer label */
47 };
48 
49 /*
50  * Inode smack data
51  */
52 struct inode_smack {
53 	char		*smk_inode;	/* label of the fso */
54 	char		*smk_task;	/* label of the task */
55 	struct mutex	smk_lock;	/* initialization lock */
56 	int		smk_flags;	/* smack inode flags */
57 };
58 
59 struct task_smack {
60 	char		*smk_task;	/* label used for access control */
61 	char		*smk_forked;	/* label when forked */
62 };
63 
64 #define	SMK_INODE_INSTANT	0x01	/* inode is instantiated */
65 #define	SMK_INODE_TRANSMUTE	0x02	/* directory is transmuting */
66 
67 /*
68  * A label access rule.
69  */
70 struct smack_rule {
71 	struct list_head	list;
72 	char			*smk_subject;
73 	char			*smk_object;
74 	int			smk_access;
75 };
76 
77 /*
78  * An entry in the table mapping smack values to
79  * CIPSO level/category-set values.
80  */
81 struct smack_cipso {
82 	int	smk_level;
83 	char	smk_catset[SMK_LABELLEN];
84 };
85 
86 /*
87  * An entry in the table identifying hosts.
88  */
89 struct smk_netlbladdr {
90 	struct list_head	list;
91 	struct sockaddr_in	smk_host;	/* network address */
92 	struct in_addr		smk_mask;	/* network mask */
93 	char			*smk_label;	/* label */
94 };
95 
96 /*
97  * This is the repository for labels seen so that it is
98  * not necessary to keep allocating tiny chuncks of memory
99  * and so that they can be shared.
100  *
101  * Labels are never modified in place. Anytime a label
102  * is imported (e.g. xattrset on a file) the list is checked
103  * for it and it is added if it doesn't exist. The address
104  * is passed out in either case. Entries are added, but
105  * never deleted.
106  *
107  * Since labels are hanging around anyway it doesn't
108  * hurt to maintain a secid for those awkward situations
109  * where kernel components that ought to use LSM independent
110  * interfaces don't. The secid should go away when all of
111  * these components have been repaired.
112  *
113  * If there is a cipso value associated with the label it
114  * gets stored here, too. This will most likely be rare as
115  * the cipso direct mapping in used internally.
116  */
117 struct smack_known {
118 	struct list_head	list;
119 	char			smk_known[SMK_LABELLEN];
120 	u32			smk_secid;
121 	struct smack_cipso	*smk_cipso;
122 	spinlock_t		smk_cipsolock; /* for changing cipso map */
123 };
124 
125 /*
126  * Mount options
127  */
128 #define SMK_FSDEFAULT	"smackfsdef="
129 #define SMK_FSFLOOR	"smackfsfloor="
130 #define SMK_FSHAT	"smackfshat="
131 #define SMK_FSROOT	"smackfsroot="
132 
133 #define SMACK_CIPSO_OPTION 	"-CIPSO"
134 
135 /*
136  * How communications on this socket are treated.
137  * Usually it's determined by the underlying netlabel code
138  * but there are certain cases, including single label hosts
139  * and potentially single label interfaces for which the
140  * treatment can not be known in advance.
141  *
142  * The possibility of additional labeling schemes being
143  * introduced in the future exists as well.
144  */
145 #define SMACK_UNLABELED_SOCKET	0
146 #define SMACK_CIPSO_SOCKET	1
147 
148 /*
149  * smackfs magic number
150  * smackfs macic number
151  */
152 #define SMACK_MAGIC	0x43415d53 /* "SMAC" */
153 
154 /*
155  * A limit on the number of entries in the lists
156  * makes some of the list administration easier.
157  */
158 #define SMACK_LIST_MAX	10000
159 
160 /*
161  * CIPSO defaults.
162  */
163 #define SMACK_CIPSO_DOI_DEFAULT		3	/* Historical */
164 #define SMACK_CIPSO_DOI_INVALID		-1	/* Not a DOI */
165 #define SMACK_CIPSO_DIRECT_DEFAULT	250	/* Arbitrary */
166 #define SMACK_CIPSO_MAXCATVAL		63	/* Bigger gets harder */
167 #define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
168 #define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
169 
170 /*
171  * Flag for transmute access
172  */
173 #define MAY_TRANSMUTE	64
174 /*
175  * Just to make the common cases easier to deal with
176  */
177 #define MAY_ANY		(MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
178 #define MAY_ANYREAD	(MAY_READ | MAY_EXEC)
179 #define MAY_ANYWRITE	(MAY_WRITE | MAY_APPEND)
180 #define MAY_READWRITE	(MAY_READ | MAY_WRITE)
181 #define MAY_NOT		0
182 
183 /*
184  * Number of access types used by Smack (rwxa)
185  */
186 #define SMK_NUM_ACCESS_TYPE 4
187 
188 /*
189  * Smack audit data; is empty if CONFIG_AUDIT not set
190  * to save some stack
191  */
192 struct smk_audit_info {
193 #ifdef CONFIG_AUDIT
194 	struct common_audit_data a;
195 #endif
196 };
197 /*
198  * These functions are in smack_lsm.c
199  */
200 struct inode_smack *new_inode_smack(char *);
201 
202 /*
203  * These functions are in smack_access.c
204  */
205 int smk_access_entry(char *, char *);
206 int smk_access(char *, char *, int, struct smk_audit_info *);
207 int smk_curacc(char *, u32, struct smk_audit_info *);
208 int smack_to_cipso(const char *, struct smack_cipso *);
209 void smack_from_cipso(u32, char *, char *);
210 char *smack_from_secid(const u32);
211 char *smk_import(const char *, int);
212 struct smack_known *smk_import_entry(const char *, int);
213 u32 smack_to_secid(const char *);
214 
215 /*
216  * Shared data.
217  */
218 extern int smack_cipso_direct;
219 extern char *smack_net_ambient;
220 extern char *smack_onlycap;
221 extern const char *smack_cipso_option;
222 
223 extern struct smack_known smack_known_floor;
224 extern struct smack_known smack_known_hat;
225 extern struct smack_known smack_known_huh;
226 extern struct smack_known smack_known_invalid;
227 extern struct smack_known smack_known_star;
228 extern struct smack_known smack_known_web;
229 
230 extern struct list_head smack_known_list;
231 extern struct list_head smack_rule_list;
232 extern struct list_head smk_netlbladdr_list;
233 
234 extern struct security_operations smack_ops;
235 
236 /*
237  * Stricly for CIPSO level manipulation.
238  * Set the category bit number in a smack label sized buffer.
239  */
240 static inline void smack_catset_bit(int cat, char *catsetp)
241 {
242 	if (cat > SMK_LABELLEN * 8)
243 		return;
244 
245 	catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
246 }
247 
248 /*
249  * Is the directory transmuting?
250  */
251 static inline int smk_inode_transmutable(const struct inode *isp)
252 {
253 	struct inode_smack *sip = isp->i_security;
254 	return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
255 }
256 
257 /*
258  * Present a pointer to the smack label in an inode blob.
259  */
260 static inline char *smk_of_inode(const struct inode *isp)
261 {
262 	struct inode_smack *sip = isp->i_security;
263 	return sip->smk_inode;
264 }
265 
266 /*
267  * Present a pointer to the smack label in an task blob.
268  */
269 static inline char *smk_of_task(const struct task_smack *tsp)
270 {
271 	return tsp->smk_task;
272 }
273 
274 /*
275  * Present a pointer to the forked smack label in an task blob.
276  */
277 static inline char *smk_of_forked(const struct task_smack *tsp)
278 {
279 	return tsp->smk_forked;
280 }
281 
282 /*
283  * Present a pointer to the smack label in the current task blob.
284  */
285 static inline char *smk_of_current(void)
286 {
287 	return smk_of_task(current_security());
288 }
289 
290 /*
291  * logging functions
292  */
293 #define SMACK_AUDIT_DENIED 0x1
294 #define SMACK_AUDIT_ACCEPT 0x2
295 extern int log_policy;
296 
297 void smack_log(char *subject_label, char *object_label,
298 		int request,
299 		int result, struct smk_audit_info *auditdata);
300 
301 #ifdef CONFIG_AUDIT
302 
303 /*
304  * some inline functions to set up audit data
305  * they do nothing if CONFIG_AUDIT is not set
306  *
307  */
308 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
309 			       char type)
310 {
311 	memset(a, 0, sizeof(*a));
312 	a->a.type = type;
313 	a->a.smack_audit_data.function = func;
314 }
315 
316 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
317 					 struct task_struct *t)
318 {
319 	a->a.u.tsk = t;
320 }
321 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
322 						    struct dentry *d)
323 {
324 	a->a.u.fs.path.dentry = d;
325 }
326 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
327 						 struct vfsmount *m)
328 {
329 	a->a.u.fs.path.mnt = m;
330 }
331 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
332 					      struct inode *i)
333 {
334 	a->a.u.fs.inode = i;
335 }
336 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
337 					     struct path p)
338 {
339 	a->a.u.fs.path = p;
340 }
341 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
342 					    struct sock *sk)
343 {
344 	a->a.u.net.sk = sk;
345 }
346 
347 #else /* no AUDIT */
348 
349 static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
350 			       char type)
351 {
352 }
353 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
354 					 struct task_struct *t)
355 {
356 }
357 static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
358 						    struct dentry *d)
359 {
360 }
361 static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
362 						 struct vfsmount *m)
363 {
364 }
365 static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
366 					      struct inode *i)
367 {
368 }
369 static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
370 					     struct path p)
371 {
372 }
373 static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
374 					    struct sock *sk)
375 {
376 }
377 #endif
378 
379 #endif  /* _SECURITY_SMACK_H */
380