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
34 #define DEBUG_ALL 0x1f /* update if new DEBUG_X added */
35 #define DEBUG_PARSE_ERROR (-1)
36
37 #define DEBUG_ON (aa_g_debug != DEBUG_NONE)
38 #define DEBUG_ABS_ROOT (aa_g_debug & DEBUG_LABEL_ABS_ROOT)
39
40 #define AA_DEBUG(opt, fmt, args...) \
41 do { \
42 if (aa_g_debug & opt) \
43 pr_warn_ratelimited("%s: " fmt, __func__, ##args); \
44 } while (0)
45 #define AA_DEBUG_LABEL(LAB, X, fmt, args...) \
46 do { \
47 if ((LAB)->flags & FLAG_DEBUG1) \
48 AA_DEBUG(X, fmt, args); \
49 } while (0)
50
51 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X)
52
53 #define AA_BUG(X, args...) \
54 do { \
55 _Pragma("GCC diagnostic ignored \"-Wformat-zero-length\""); \
56 AA_BUG_FMT((X), "" args); \
57 _Pragma("GCC diagnostic warning \"-Wformat-zero-length\""); \
58 } while (0)
59 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS
60 #define AA_BUG_FMT(X, fmt, args...) \
61 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args)
62 #else
63 #define AA_BUG_FMT(X, fmt, args...) \
64 do { \
65 BUILD_BUG_ON_INVALID(X); \
66 no_printk(fmt, ##args); \
67 } while (0)
68 #endif
69
70 int aa_parse_debug_params(const char *str);
71 int aa_print_debug_params(char *buffer);
72
73 #define AA_ERROR(fmt, args...) \
74 pr_err_ratelimited("AppArmor: " fmt, ##args)
75
76 /* Flag indicating whether initialization completed */
77 extern int apparmor_initialized;
78
79 /* fn's in lib */
80 const char *skipn_spaces(const char *str, size_t n);
81 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
82 size_t *ns_len);
83 void aa_info_message(const char *str);
84
85 /* Security blob offsets */
86 extern struct lsm_blob_sizes apparmor_blob_sizes;
87
88 /**
89 * aa_strneq - compare null terminated @str to a non null terminated substring
90 * @str: a null terminated string
91 * @sub: a substring, not necessarily null terminated
92 * @len: length of @sub to compare
93 *
94 * The @str string must be full consumed for this to be considered a match
95 */
aa_strneq(const char * str,const char * sub,int len)96 static inline bool aa_strneq(const char *str, const char *sub, int len)
97 {
98 return !strncmp(str, sub, len) && !str[len];
99 }
100
101 /**
102 * aa_dfa_null_transition - step to next state after null character
103 * @dfa: the dfa to match against
104 * @start: the state of the dfa to start matching in
105 *
106 * aa_dfa_null_transition transitions to the next state after a null
107 * character which is not used in standard matching and is only
108 * used to separate pairs.
109 */
aa_dfa_null_transition(struct aa_dfa * dfa,aa_state_t start)110 static inline aa_state_t aa_dfa_null_transition(struct aa_dfa *dfa,
111 aa_state_t start)
112 {
113 /* the null transition only needs the string's null terminator byte */
114 return aa_dfa_next(dfa, start, 0);
115 }
116
path_mediated_fs(struct dentry * dentry)117 static inline bool path_mediated_fs(struct dentry *dentry)
118 {
119 return !(dentry->d_sb->s_flags & SB_NOUSER);
120 }
121
122 struct aa_str_table {
123 int size;
124 char **table;
125 };
126
127 void aa_free_str_table(struct aa_str_table *table);
128 bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp);
129
130 struct counted_str {
131 struct kref count;
132 char name[];
133 };
134
135 #define str_to_counted(str) \
136 ((struct counted_str *)(str - offsetof(struct counted_str, name)))
137
138 #define __counted /* atm just a notation */
139
140 void aa_str_kref(struct kref *kref);
141 char *aa_str_alloc(int size, gfp_t gfp);
142
143
aa_get_str(__counted char * str)144 static inline __counted char *aa_get_str(__counted char *str)
145 {
146 if (str)
147 kref_get(&(str_to_counted(str)->count));
148
149 return str;
150 }
151
aa_put_str(__counted char * str)152 static inline void aa_put_str(__counted char *str)
153 {
154 if (str)
155 kref_put(&str_to_counted(str)->count, aa_str_kref);
156 }
157
158
159 /* struct aa_policy - common part of both namespaces and profiles
160 * @name: name of the object
161 * @hname - The hierarchical name
162 * @list: list policy object is on
163 * @profiles: head of the profiles list contained in the object
164 */
165 struct aa_policy {
166 const char *name;
167 __counted char *hname;
168 struct list_head list;
169 struct list_head profiles;
170 };
171
172 /**
173 * basename - find the last component of an hname
174 * @hname: hname to find the base profile name component of (NOT NULL)
175 *
176 * Returns: the tail (base profile name) name component of an hname
177 */
basename(const char * hname)178 static inline const char *basename(const char *hname)
179 {
180 char *split;
181
182 hname = strim((char *)hname);
183 for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
184 hname = split + 2;
185
186 return hname;
187 }
188
189 /**
190 * __policy_find - find a policy by @name on a policy list
191 * @head: list to search (NOT NULL)
192 * @name: name to search for (NOT NULL)
193 *
194 * Requires: rcu_read_lock be held
195 *
196 * Returns: unrefcounted policy that match @name or NULL if not found
197 */
__policy_find(struct list_head * head,const char * name)198 static inline struct aa_policy *__policy_find(struct list_head *head,
199 const char *name)
200 {
201 struct aa_policy *policy;
202
203 list_for_each_entry_rcu(policy, head, list) {
204 if (!strcmp(policy->name, name))
205 return policy;
206 }
207 return NULL;
208 }
209
210 /**
211 * __policy_strn_find - find a policy that's name matches @len chars of @str
212 * @head: list to search (NOT NULL)
213 * @str: string to search for (NOT NULL)
214 * @len: length of match required
215 *
216 * Requires: rcu_read_lock be held
217 *
218 * Returns: unrefcounted policy that match @str or NULL if not found
219 *
220 * if @len == strlen(@strlen) then this is equiv to __policy_find
221 * other wise it allows searching for policy by a partial match of name
222 */
__policy_strn_find(struct list_head * head,const char * str,int len)223 static inline struct aa_policy *__policy_strn_find(struct list_head *head,
224 const char *str, int len)
225 {
226 struct aa_policy *policy;
227
228 list_for_each_entry_rcu(policy, head, list) {
229 if (aa_strneq(policy->name, str, len))
230 return policy;
231 }
232
233 return NULL;
234 }
235
236 bool aa_policy_init(struct aa_policy *policy, const char *prefix,
237 const char *name, gfp_t gfp);
238 void aa_policy_destroy(struct aa_policy *policy);
239
240
241 /*
242 * fn_label_build - abstract out the build of a label transition
243 * @L: label the transition is being computed for
244 * @P: profile parameter derived from L by this macro, can be passed to FN
245 * @GFP: memory allocation type to use
246 * @FN: fn to call for each profile transition. @P is set to the profile
247 *
248 * Returns: new label on success
249 * ERR_PTR if build @FN fails
250 * NULL if label_build fails due to low memory conditions
251 *
252 * @FN must return a label or ERR_PTR on failure. NULL is not allowed
253 */
254 #define fn_label_build(L, P, GFP, FN) \
255 ({ \
256 __label__ __do_cleanup, __done; \
257 struct aa_label *__new_; \
258 \
259 if ((L)->size > 1) { \
260 /* TODO: add cache of transitions already done */ \
261 struct label_it __i; \
262 int __j, __k, __count; \
263 DEFINE_VEC(label, __lvec); \
264 DEFINE_VEC(profile, __pvec); \
265 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \
266 __new_ = NULL; \
267 goto __done; \
268 } \
269 __j = 0; \
270 label_for_each(__i, (L), (P)) { \
271 __new_ = (FN); \
272 AA_BUG(!__new_); \
273 if (IS_ERR(__new_)) \
274 goto __do_cleanup; \
275 __lvec[__j++] = __new_; \
276 } \
277 for (__j = __count = 0; __j < (L)->size; __j++) \
278 __count += __lvec[__j]->size; \
279 if (!vec_setup(profile, __pvec, __count, (GFP))) { \
280 for (__j = __k = 0; __j < (L)->size; __j++) { \
281 label_for_each(__i, __lvec[__j], (P)) \
282 __pvec[__k++] = aa_get_profile(P); \
283 } \
284 __count -= aa_vec_unique(__pvec, __count, 0); \
285 if (__count > 1) { \
286 __new_ = aa_vec_find_or_create_label(__pvec,\
287 __count, (GFP)); \
288 /* only fails if out of Mem */ \
289 if (!__new_) \
290 __new_ = NULL; \
291 } else \
292 __new_ = aa_get_label(&__pvec[0]->label); \
293 vec_cleanup(profile, __pvec, __count); \
294 } else \
295 __new_ = NULL; \
296 __do_cleanup: \
297 vec_cleanup(label, __lvec, (L)->size); \
298 } else { \
299 (P) = labels_profile(L); \
300 __new_ = (FN); \
301 } \
302 __done: \
303 if (!__new_) \
304 AA_DEBUG(DEBUG_LABEL, "label build failed\n"); \
305 (__new_); \
306 })
307
308
309 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \
310 ({ \
311 struct aa_label *__new; \
312 if ((P)->ns != (NS)) \
313 __new = (OTHER_FN); \
314 else \
315 __new = (NS_FN); \
316 (__new); \
317 })
318
319 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \
320 ({ \
321 fn_label_build((L), (P), (GFP), \
322 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \
323 })
324
325 #endif /* __AA_LIB_H */
326