1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * AppArmor security module
4 *
5 * This file contains AppArmor lib definitions
6 *
7 * 2017 Canonical Ltd.
8 */
9
10 #ifndef __AA_LIB_H
11 #define __AA_LIB_H
12
13 #include <linux/slab.h>
14 #include <linux/fs.h>
15 #include <linux/lsm_hooks.h>
16
17 #include "match.h"
18
19 extern struct aa_dfa *stacksplitdfa;
20
21 /*
22 * split individual debug cases out in preparation for finer grained
23 * debug controls in the future.
24 */
25 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args)
26
27 #define DEBUG_NONE 0
28 #define DEBUG_LABEL_ABS_ROOT 1
29 #define DEBUG_LABEL 2
30 #define DEBUG_DOMAIN 4
31 #define DEBUG_POLICY 8
32 #define DEBUG_INTERFACE 0x10
33 #define DEBUG_UNPACK 0x20
34 #define DEBUG_TAGS 0x40
35
36 #define DEBUG_ALL 0x7f /* update if new DEBUG_X added */
37 #define DEBUG_PARSE_ERROR (-1)
38
39 #define DEBUG_ON (aa_g_debug != DEBUG_NONE)
40 #define DEBUG_ABS_ROOT (aa_g_debug & DEBUG_LABEL_ABS_ROOT)
41
42 #define AA_DEBUG(opt, fmt, args...) \
43 do { \
44 if (aa_g_debug & opt) \
45 pr_warn_ratelimited("%s: " fmt, __func__, ##args); \
46 } while (0)
47 #define AA_DEBUG_LABEL(LAB, X, fmt, args...) \
48 do { \
49 if ((LAB)->flags & FLAG_DEBUG1) \
50 AA_DEBUG(X, fmt, ##args); \
51 } while (0)
52
53 #define AA_DEBUG_PROFILE(PROF, X, fmt...) AA_DEBUG_LABEL(&(PROF)->label, X, ##fmt)
54
55 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X)
56
57 #define AA_BUG(X, args...) \
58 do { \
59 _Pragma("GCC diagnostic ignored \"-Wformat-zero-length\""); \
60 AA_BUG_FMT((X), "" args); \
61 _Pragma("GCC diagnostic warning \"-Wformat-zero-length\""); \
62 } while (0)
63 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS
64 #define AA_BUG_FMT(X, fmt, args...) \
65 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args)
66 #else
67 #define AA_BUG_FMT(X, fmt, args...) \
68 do { \
69 BUILD_BUG_ON_INVALID(X); \
70 no_printk(fmt, ##args); \
71 } while (0)
72 #endif
73
74 int aa_parse_debug_params(const char *str);
75 int aa_print_debug_params(char *buffer);
76
77 #define AA_ERROR(fmt, args...) \
78 pr_err_ratelimited("AppArmor: " fmt, ##args)
79
80 /* Flag indicating whether initialization completed */
81 extern int apparmor_initialized;
82
83 /* semantic split of scope and view */
84 #define aa_in_scope(SUBJ, OBJ) \
85 aa_ns_visible(SUBJ, OBJ, false)
86
87 #define aa_in_view(SUBJ, OBJ) \
88 aa_ns_visible(SUBJ, OBJ, true)
89
90 #define label_for_each_in_scope(I, NS, L, P) \
91 label_for_each_in_ns(I, NS, L, P)
92
93 #define fn_for_each_in_scope(L, P, FN) \
94 fn_for_each_in_ns(L, P, FN)
95
96 /* fn's in lib */
97 const char *skipn_spaces(const char *str, size_t n);
98 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
99 size_t *ns_len);
100 void aa_info_message(const char *str);
101
102 /* Security blob offsets */
103 extern struct lsm_blob_sizes apparmor_blob_sizes;
104
105 /**
106 * aa_strneq - compare null terminated @str to a non null terminated substring
107 * @str: a null terminated string
108 * @sub: a substring, not necessarily null terminated
109 * @len: length of @sub to compare
110 *
111 * The @str string must be full consumed for this to be considered a match
112 */
aa_strneq(const char * str,const char * sub,int len)113 static inline bool aa_strneq(const char *str, const char *sub, int len)
114 {
115 return !strncmp(str, sub, len) && !str[len];
116 }
117
118 /**
119 * aa_dfa_null_transition - step to next state after null character
120 * @dfa: the dfa to match against
121 * @start: the state of the dfa to start matching in
122 *
123 * aa_dfa_null_transition transitions to the next state after a null
124 * character which is not used in standard matching and is only
125 * used to separate pairs.
126 */
aa_dfa_null_transition(struct aa_dfa * dfa,aa_state_t start)127 static inline aa_state_t aa_dfa_null_transition(struct aa_dfa *dfa,
128 aa_state_t start)
129 {
130 /* the null transition only needs the string's null terminator byte */
131 return aa_dfa_next(dfa, start, 0);
132 }
133
path_mediated_fs(struct dentry * dentry)134 static inline bool path_mediated_fs(struct dentry *dentry)
135 {
136 return !(dentry->d_sb->s_flags & SB_NOUSER);
137 }
138
139 struct aa_str_table_ent {
140 int count;
141 int size;
142 char *strs;
143 };
144
145 struct aa_str_table {
146 int size;
147 struct aa_str_table_ent *table;
148 };
149
150 bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp);
151 void aa_destroy_str_table(struct aa_str_table *table);
152
153 struct counted_str {
154 struct kref count;
155 char name[];
156 };
157
158 #define str_to_counted(str) \
159 ((struct counted_str *)(str - offsetof(struct counted_str, name)))
160
161 #define __counted /* atm just a notation */
162
163 void aa_str_kref(struct kref *kref);
164 char *aa_str_alloc(int size, gfp_t gfp);
165
166
aa_get_str(__counted char * str)167 static inline __counted char *aa_get_str(__counted char *str)
168 {
169 if (str)
170 kref_get(&(str_to_counted(str)->count));
171
172 return str;
173 }
174
aa_put_str(__counted char * str)175 static inline void aa_put_str(__counted char *str)
176 {
177 if (str)
178 kref_put(&str_to_counted(str)->count, aa_str_kref);
179 }
180
181
182 /* struct aa_policy - common part of both namespaces and profiles
183 * @name: name of the object
184 * @hname - The hierarchical name
185 * @list: list policy object is on
186 * @profiles: head of the profiles list contained in the object
187 */
188 struct aa_policy {
189 const char *name;
190 __counted char *hname;
191 struct list_head list;
192 struct list_head profiles;
193 };
194
195 /**
196 * basename - find the last component of an hname
197 * @hname: hname to find the base profile name component of (NOT NULL)
198 *
199 * Returns: the tail (base profile name) name component of an hname
200 */
basename(const char * hname)201 static inline const char *basename(const char *hname)
202 {
203 char *split;
204
205 hname = strim((char *)hname);
206 for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
207 hname = split + 2;
208
209 return hname;
210 }
211
212 /**
213 * __policy_find - find a policy by @name on a policy list
214 * @head: list to search (NOT NULL)
215 * @name: name to search for (NOT NULL)
216 *
217 * Requires: rcu_read_lock be held
218 *
219 * Returns: unrefcounted policy that match @name or NULL if not found
220 */
__policy_find(struct list_head * head,const char * name)221 static inline struct aa_policy *__policy_find(struct list_head *head,
222 const char *name)
223 {
224 struct aa_policy *policy;
225
226 list_for_each_entry_rcu(policy, head, list) {
227 if (!strcmp(policy->name, name))
228 return policy;
229 }
230 return NULL;
231 }
232
233 /**
234 * __policy_strn_find - find a policy that's name matches @len chars of @str
235 * @head: list to search (NOT NULL)
236 * @str: string to search for (NOT NULL)
237 * @len: length of match required
238 *
239 * Requires: rcu_read_lock be held
240 *
241 * Returns: unrefcounted policy that match @str or NULL if not found
242 *
243 * if @len == strlen(@strlen) then this is equiv to __policy_find
244 * other wise it allows searching for policy by a partial match of name
245 */
__policy_strn_find(struct list_head * head,const char * str,int len)246 static inline struct aa_policy *__policy_strn_find(struct list_head *head,
247 const char *str, int len)
248 {
249 struct aa_policy *policy;
250
251 list_for_each_entry_rcu(policy, head, list) {
252 if (aa_strneq(policy->name, str, len))
253 return policy;
254 }
255
256 return NULL;
257 }
258
259 bool aa_policy_init(struct aa_policy *policy, const char *prefix,
260 const char *name, gfp_t gfp);
261 void aa_policy_destroy(struct aa_policy *policy);
262
263
264 /*
265 * fn_label_build - abstract out the build of a label transition
266 * @L: label the transition is being computed for
267 * @P: profile parameter derived from L by this macro, can be passed to FN
268 * @GFP: memory allocation type to use
269 * @FN: fn to call for each profile transition. @P is set to the profile
270 *
271 * Returns: new label on success
272 * ERR_PTR if build @FN fails
273 * NULL if label_build fails due to low memory conditions
274 *
275 * @FN must return a label or ERR_PTR on failure. NULL is not allowed
276 */
277 #define fn_label_build(L, P, GFP, FN) \
278 ({ \
279 __label__ __do_cleanup, __done; \
280 struct aa_label *__new_; \
281 \
282 if ((L)->size > 1) { \
283 /* TODO: add cache of transitions already done */ \
284 struct label_it __i; \
285 int __j, __k, __count; \
286 DEFINE_VEC(label, __lvec); \
287 DEFINE_VEC(profile, __pvec); \
288 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \
289 __new_ = NULL; \
290 goto __done; \
291 } \
292 __j = 0; \
293 label_for_each(__i, (L), (P)) { \
294 __new_ = (FN); \
295 AA_BUG(!__new_); \
296 if (IS_ERR(__new_)) \
297 goto __do_cleanup; \
298 __lvec[__j++] = __new_; \
299 } \
300 for (__j = __count = 0; __j < (L)->size; __j++) \
301 __count += __lvec[__j]->size; \
302 if (!vec_setup(profile, __pvec, __count, (GFP))) { \
303 for (__j = __k = 0; __j < (L)->size; __j++) { \
304 label_for_each(__i, __lvec[__j], (P)) \
305 __pvec[__k++] = aa_get_profile(P); \
306 } \
307 __count -= aa_vec_unique(__pvec, __count, 0); \
308 if (__count > 1) { \
309 __new_ = aa_vec_find_or_create_label(__pvec,\
310 __count, (GFP)); \
311 /* only fails if out of Mem */ \
312 if (!__new_) \
313 __new_ = NULL; \
314 } else \
315 __new_ = aa_get_label(&__pvec[0]->label); \
316 vec_cleanup(profile, __pvec, __count); \
317 } else \
318 __new_ = NULL; \
319 __do_cleanup: \
320 vec_cleanup(label, __lvec, (L)->size); \
321 } else { \
322 (P) = labels_profile(L); \
323 __new_ = (FN); \
324 } \
325 __done: \
326 if (!__new_) \
327 AA_DEBUG(DEBUG_LABEL, "label build failed\n"); \
328 (__new_); \
329 })
330
331
332 #define __fn_build_in_scope(NS, P, NS_FN, OTHER_FN) \
333 ({ \
334 struct aa_label *__new; \
335 if ((P)->ns != (NS)) \
336 __new = (OTHER_FN); \
337 else \
338 __new = (NS_FN); \
339 (__new); \
340 })
341
342 #define fn_label_build_in_scope(L, P, GFP, NS_FN, OTHER_FN) \
343 ({ \
344 fn_label_build((L), (P), (GFP), \
345 __fn_build_in_scope(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \
346 })
347
348 #endif /* __AA_LIB_H */
349