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 enum reftype {
106 REF_NS,
107 REF_PROXY,
108 REF_RAWDATA,
109 };
110
111 /* common reference count used by data the shows up in aafs */
112 struct aa_common_ref {
113 struct kref count;
114 enum reftype reftype;
115 };
116
117 /**
118 * aa_strneq - compare null terminated @str to a non null terminated substring
119 * @str: a null terminated string
120 * @sub: a substring, not necessarily null terminated
121 * @len: length of @sub to compare
122 *
123 * The @str string must be full consumed for this to be considered a match
124 */
aa_strneq(const char * str,const char * sub,int len)125 static inline bool aa_strneq(const char *str, const char *sub, int len)
126 {
127 return !strncmp(str, sub, len) && !str[len];
128 }
129
130 /**
131 * aa_dfa_null_transition - step to next state after null character
132 * @dfa: the dfa to match against
133 * @start: the state of the dfa to start matching in
134 *
135 * aa_dfa_null_transition transitions to the next state after a null
136 * character which is not used in standard matching and is only
137 * used to separate pairs.
138 */
aa_dfa_null_transition(struct aa_dfa * dfa,aa_state_t start)139 static inline aa_state_t aa_dfa_null_transition(struct aa_dfa *dfa,
140 aa_state_t start)
141 {
142 /* the null transition only needs the string's null terminator byte */
143 return aa_dfa_next(dfa, start, 0);
144 }
145
path_mediated_fs(struct dentry * dentry)146 static inline bool path_mediated_fs(struct dentry *dentry)
147 {
148 return !(dentry->d_sb->s_flags & SB_NOUSER);
149 }
150
151 struct aa_str_table_ent {
152 int count;
153 int size;
154 char *strs;
155 };
156
157 struct aa_str_table {
158 int size;
159 struct aa_str_table_ent *table;
160 };
161
162 bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp);
163 void aa_destroy_str_table(struct aa_str_table *table);
164
165 struct counted_str {
166 struct kref count;
167 char name[];
168 };
169
170 #define str_to_counted(str) \
171 ((struct counted_str *)(str - offsetof(struct counted_str, name)))
172
173 #define __counted /* atm just a notation */
174
175 void aa_str_kref(struct kref *kref);
176 char *aa_str_alloc(int size, gfp_t gfp);
177
178
aa_get_str(__counted char * str)179 static inline __counted char *aa_get_str(__counted char *str)
180 {
181 if (str)
182 kref_get(&(str_to_counted(str)->count));
183
184 return str;
185 }
186
aa_put_str(__counted char * str)187 static inline void aa_put_str(__counted char *str)
188 {
189 if (str)
190 kref_put(&str_to_counted(str)->count, aa_str_kref);
191 }
192
193
194 /* struct aa_policy - common part of both namespaces and profiles
195 * @name: name of the object
196 * @hname - The hierarchical name
197 * @list: list policy object is on
198 * @profiles: head of the profiles list contained in the object
199 */
200 struct aa_policy {
201 const char *name;
202 __counted char *hname;
203 struct list_head list;
204 struct list_head profiles;
205 };
206
207 /**
208 * basename - find the last component of an hname
209 * @hname: hname to find the base profile name component of (NOT NULL)
210 *
211 * Returns: the tail (base profile name) name component of an hname
212 */
basename(const char * hname)213 static inline const char *basename(const char *hname)
214 {
215 char *split;
216
217 hname = strim((char *)hname);
218 for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
219 hname = split + 2;
220
221 return hname;
222 }
223
224 /**
225 * __policy_find - find a policy by @name on a policy list
226 * @head: list to search (NOT NULL)
227 * @name: name to search for (NOT NULL)
228 *
229 * Requires: rcu_read_lock be held
230 *
231 * Returns: unrefcounted policy that match @name or NULL if not found
232 */
__policy_find(struct list_head * head,const char * name)233 static inline struct aa_policy *__policy_find(struct list_head *head,
234 const char *name)
235 {
236 struct aa_policy *policy;
237
238 list_for_each_entry_rcu(policy, head, list) {
239 if (!strcmp(policy->name, name))
240 return policy;
241 }
242 return NULL;
243 }
244
245 /**
246 * __policy_strn_find - find a policy that's name matches @len chars of @str
247 * @head: list to search (NOT NULL)
248 * @str: string to search for (NOT NULL)
249 * @len: length of match required
250 *
251 * Requires: rcu_read_lock be held
252 *
253 * Returns: unrefcounted policy that match @str or NULL if not found
254 *
255 * if @len == strlen(@strlen) then this is equiv to __policy_find
256 * other wise it allows searching for policy by a partial match of name
257 */
__policy_strn_find(struct list_head * head,const char * str,int len)258 static inline struct aa_policy *__policy_strn_find(struct list_head *head,
259 const char *str, int len)
260 {
261 struct aa_policy *policy;
262
263 list_for_each_entry_rcu(policy, head, list) {
264 if (aa_strneq(policy->name, str, len))
265 return policy;
266 }
267
268 return NULL;
269 }
270
271 bool aa_policy_init(struct aa_policy *policy, const char *prefix,
272 const char *name, gfp_t gfp);
273 void aa_policy_destroy(struct aa_policy *policy);
274
275
276 /*
277 * fn_label_build - abstract out the build of a label transition
278 * @L: label the transition is being computed for
279 * @P: profile parameter derived from L by this macro, can be passed to FN
280 * @GFP: memory allocation type to use
281 * @FN: fn to call for each profile transition. @P is set to the profile
282 *
283 * Returns: new label on success
284 * ERR_PTR if build @FN fails
285 * NULL if label_build fails due to low memory conditions
286 *
287 * @FN must return a label or ERR_PTR on failure. NULL is not allowed
288 */
289 #define fn_label_build(L, P, GFP, FN) \
290 ({ \
291 __label__ __do_cleanup, __done; \
292 struct aa_label *__new_; \
293 \
294 if ((L)->size > 1) { \
295 /* TODO: add cache of transitions already done */ \
296 struct label_it __i; \
297 int __j, __k, __count; \
298 DEFINE_VEC(label, __lvec); \
299 DEFINE_VEC(profile, __pvec); \
300 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \
301 __new_ = NULL; \
302 goto __done; \
303 } \
304 __j = 0; \
305 label_for_each(__i, (L), (P)) { \
306 __new_ = (FN); \
307 AA_BUG(!__new_); \
308 if (IS_ERR(__new_)) \
309 goto __do_cleanup; \
310 __lvec[__j++] = __new_; \
311 } \
312 for (__j = __count = 0; __j < (L)->size; __j++) \
313 __count += __lvec[__j]->size; \
314 if (!vec_setup(profile, __pvec, __count, (GFP))) { \
315 for (__j = __k = 0; __j < (L)->size; __j++) { \
316 label_for_each(__i, __lvec[__j], (P)) \
317 __pvec[__k++] = aa_get_profile(P); \
318 } \
319 __count -= aa_vec_unique(__pvec, __count, 0); \
320 if (__count > 1) { \
321 __new_ = aa_vec_find_or_create_label(__pvec,\
322 __count, (GFP)); \
323 /* only fails if out of Mem */ \
324 if (!__new_) \
325 __new_ = NULL; \
326 } else \
327 __new_ = aa_get_label(&__pvec[0]->label); \
328 vec_cleanup(profile, __pvec, __count); \
329 } else \
330 __new_ = NULL; \
331 __do_cleanup: \
332 vec_cleanup(label, __lvec, (L)->size); \
333 } else { \
334 (P) = labels_profile(L); \
335 __new_ = (FN); \
336 } \
337 __done: \
338 if (!__new_) \
339 AA_DEBUG(DEBUG_LABEL, "label build failed\n"); \
340 (__new_); \
341 })
342
343
344 #define __fn_build_in_scope(NS, P, NS_FN, OTHER_FN) \
345 ({ \
346 struct aa_label *__new; \
347 if ((P)->ns != (NS)) \
348 __new = (OTHER_FN); \
349 else \
350 __new = (NS_FN); \
351 (__new); \
352 })
353
354 #define fn_label_build_in_scope(L, P, GFP, NS_FN, OTHER_FN) \
355 ({ \
356 fn_label_build((L), (P), (GFP), \
357 __fn_build_in_scope(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \
358 })
359
360 #endif /* __AA_LIB_H */
361