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 * DEBUG remains global (no per profile flag) since it is mostly used in sysctl
23 * which is not related to profile accesses.
24 */
25
26 #define DEBUG_ON (aa_g_debug)
27 /*
28 * split individual debug cases out in preparation for finer grained
29 * debug controls in the future.
30 */
31 #define AA_DEBUG_LABEL DEBUG_ON
32 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args)
33 #define AA_DEBUG(fmt, args...) \
34 do { \
35 if (DEBUG_ON) \
36 pr_debug_ratelimited("AppArmor: " fmt, ##args); \
37 } while (0)
38
39 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X)
40
41 #define AA_BUG(X, args...) \
42 do { \
43 _Pragma("GCC diagnostic ignored \"-Wformat-zero-length\""); \
44 AA_BUG_FMT((X), "" args); \
45 _Pragma("GCC diagnostic warning \"-Wformat-zero-length\""); \
46 } while (0)
47 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS
48 #define AA_BUG_FMT(X, fmt, args...) \
49 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args)
50 #else
51 #define AA_BUG_FMT(X, fmt, args...) no_printk(fmt, ##args)
52 #endif
53
54 #define AA_ERROR(fmt, args...) \
55 pr_err_ratelimited("AppArmor: " fmt, ##args)
56
57 /* Flag indicating whether initialization completed */
58 extern int apparmor_initialized;
59
60 /* fn's in lib */
61 const char *skipn_spaces(const char *str, size_t n);
62 char *aa_split_fqname(char *args, char **ns_name);
63 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
64 size_t *ns_len);
65 void aa_info_message(const char *str);
66
67 /* Security blob offsets */
68 extern struct lsm_blob_sizes apparmor_blob_sizes;
69
70 /**
71 * aa_strneq - compare null terminated @str to a non null terminated substring
72 * @str: a null terminated string
73 * @sub: a substring, not necessarily null terminated
74 * @len: length of @sub to compare
75 *
76 * The @str string must be full consumed for this to be considered a match
77 */
aa_strneq(const char * str,const char * sub,int len)78 static inline bool aa_strneq(const char *str, const char *sub, int len)
79 {
80 return !strncmp(str, sub, len) && !str[len];
81 }
82
83 /**
84 * aa_dfa_null_transition - step to next state after null character
85 * @dfa: the dfa to match against
86 * @start: the state of the dfa to start matching in
87 *
88 * aa_dfa_null_transition transitions to the next state after a null
89 * character which is not used in standard matching and is only
90 * used to separate pairs.
91 */
aa_dfa_null_transition(struct aa_dfa * dfa,aa_state_t start)92 static inline aa_state_t aa_dfa_null_transition(struct aa_dfa *dfa,
93 aa_state_t start)
94 {
95 /* the null transition only needs the string's null terminator byte */
96 return aa_dfa_next(dfa, start, 0);
97 }
98
path_mediated_fs(struct dentry * dentry)99 static inline bool path_mediated_fs(struct dentry *dentry)
100 {
101 return !(dentry->d_sb->s_flags & SB_NOUSER);
102 }
103
104 struct aa_str_table {
105 int size;
106 char **table;
107 };
108
109 void aa_free_str_table(struct aa_str_table *table);
110
111 struct counted_str {
112 struct kref count;
113 char name[];
114 };
115
116 #define str_to_counted(str) \
117 ((struct counted_str *)(str - offsetof(struct counted_str, name)))
118
119 #define __counted /* atm just a notation */
120
121 void aa_str_kref(struct kref *kref);
122 char *aa_str_alloc(int size, gfp_t gfp);
123
124
aa_get_str(__counted char * str)125 static inline __counted char *aa_get_str(__counted char *str)
126 {
127 if (str)
128 kref_get(&(str_to_counted(str)->count));
129
130 return str;
131 }
132
aa_put_str(__counted char * str)133 static inline void aa_put_str(__counted char *str)
134 {
135 if (str)
136 kref_put(&str_to_counted(str)->count, aa_str_kref);
137 }
138
139
140 /* struct aa_policy - common part of both namespaces and profiles
141 * @name: name of the object
142 * @hname - The hierarchical name
143 * @list: list policy object is on
144 * @profiles: head of the profiles list contained in the object
145 */
146 struct aa_policy {
147 const char *name;
148 __counted char *hname;
149 struct list_head list;
150 struct list_head profiles;
151 };
152
153 /**
154 * basename - find the last component of an hname
155 * @name: hname to find the base profile name component of (NOT NULL)
156 *
157 * Returns: the tail (base profile name) name component of an hname
158 */
basename(const char * hname)159 static inline const char *basename(const char *hname)
160 {
161 char *split;
162
163 hname = strim((char *)hname);
164 for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
165 hname = split + 2;
166
167 return hname;
168 }
169
170 /**
171 * __policy_find - find a policy by @name on a policy list
172 * @head: list to search (NOT NULL)
173 * @name: name to search for (NOT NULL)
174 *
175 * Requires: rcu_read_lock be held
176 *
177 * Returns: unrefcounted policy that match @name or NULL if not found
178 */
__policy_find(struct list_head * head,const char * name)179 static inline struct aa_policy *__policy_find(struct list_head *head,
180 const char *name)
181 {
182 struct aa_policy *policy;
183
184 list_for_each_entry_rcu(policy, head, list) {
185 if (!strcmp(policy->name, name))
186 return policy;
187 }
188 return NULL;
189 }
190
191 /**
192 * __policy_strn_find - find a policy that's name matches @len chars of @str
193 * @head: list to search (NOT NULL)
194 * @str: string to search for (NOT NULL)
195 * @len: length of match required
196 *
197 * Requires: rcu_read_lock be held
198 *
199 * Returns: unrefcounted policy that match @str or NULL if not found
200 *
201 * if @len == strlen(@strlen) then this is equiv to __policy_find
202 * other wise it allows searching for policy by a partial match of name
203 */
__policy_strn_find(struct list_head * head,const char * str,int len)204 static inline struct aa_policy *__policy_strn_find(struct list_head *head,
205 const char *str, int len)
206 {
207 struct aa_policy *policy;
208
209 list_for_each_entry_rcu(policy, head, list) {
210 if (aa_strneq(policy->name, str, len))
211 return policy;
212 }
213
214 return NULL;
215 }
216
217 bool aa_policy_init(struct aa_policy *policy, const char *prefix,
218 const char *name, gfp_t gfp);
219 void aa_policy_destroy(struct aa_policy *policy);
220
221
222 /*
223 * fn_label_build - abstract out the build of a label transition
224 * @L: label the transition is being computed for
225 * @P: profile parameter derived from L by this macro, can be passed to FN
226 * @GFP: memory allocation type to use
227 * @FN: fn to call for each profile transition. @P is set to the profile
228 *
229 * Returns: new label on success
230 * ERR_PTR if build @FN fails
231 * NULL if label_build fails due to low memory conditions
232 *
233 * @FN must return a label or ERR_PTR on failure. NULL is not allowed
234 */
235 #define fn_label_build(L, P, GFP, FN) \
236 ({ \
237 __label__ __do_cleanup, __done; \
238 struct aa_label *__new_; \
239 \
240 if ((L)->size > 1) { \
241 /* TODO: add cache of transitions already done */ \
242 struct label_it __i; \
243 int __j, __k, __count; \
244 DEFINE_VEC(label, __lvec); \
245 DEFINE_VEC(profile, __pvec); \
246 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \
247 __new_ = NULL; \
248 goto __done; \
249 } \
250 __j = 0; \
251 label_for_each(__i, (L), (P)) { \
252 __new_ = (FN); \
253 AA_BUG(!__new_); \
254 if (IS_ERR(__new_)) \
255 goto __do_cleanup; \
256 __lvec[__j++] = __new_; \
257 } \
258 for (__j = __count = 0; __j < (L)->size; __j++) \
259 __count += __lvec[__j]->size; \
260 if (!vec_setup(profile, __pvec, __count, (GFP))) { \
261 for (__j = __k = 0; __j < (L)->size; __j++) { \
262 label_for_each(__i, __lvec[__j], (P)) \
263 __pvec[__k++] = aa_get_profile(P); \
264 } \
265 __count -= aa_vec_unique(__pvec, __count, 0); \
266 if (__count > 1) { \
267 __new_ = aa_vec_find_or_create_label(__pvec,\
268 __count, (GFP)); \
269 /* only fails if out of Mem */ \
270 if (!__new_) \
271 __new_ = NULL; \
272 } else \
273 __new_ = aa_get_label(&__pvec[0]->label); \
274 vec_cleanup(profile, __pvec, __count); \
275 } else \
276 __new_ = NULL; \
277 __do_cleanup: \
278 vec_cleanup(label, __lvec, (L)->size); \
279 } else { \
280 (P) = labels_profile(L); \
281 __new_ = (FN); \
282 } \
283 __done: \
284 if (!__new_) \
285 AA_DEBUG("label build failed\n"); \
286 (__new_); \
287 })
288
289
290 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \
291 ({ \
292 struct aa_label *__new; \
293 if ((P)->ns != (NS)) \
294 __new = (OTHER_FN); \
295 else \
296 __new = (NS_FN); \
297 (__new); \
298 })
299
300 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \
301 ({ \
302 fn_label_build((L), (P), (GFP), \
303 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \
304 })
305
306 #endif /* __AA_LIB_H */
307