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 /*
20 * DEBUG remains global (no per profile flag) since it is mostly used in sysctl
21 * which is not related to profile accesses.
22 */
23
24 #define DEBUG_ON (aa_g_debug)
25 /*
26 * split individual debug cases out in preparation for finer grained
27 * debug controls in the future.
28 */
29 #define AA_DEBUG_LABEL DEBUG_ON
30 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args)
31 #define AA_DEBUG(fmt, args...) \
32 do { \
33 if (DEBUG_ON) \
34 pr_debug_ratelimited("AppArmor: " fmt, ##args); \
35 } while (0)
36
37 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X)
38
39 #define AA_BUG(X, args...) \
40 do { \
41 _Pragma("GCC diagnostic ignored \"-Wformat-zero-length\""); \
42 AA_BUG_FMT((X), "" args); \
43 _Pragma("GCC diagnostic warning \"-Wformat-zero-length\""); \
44 } while (0)
45 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS
46 #define AA_BUG_FMT(X, fmt, args...) \
47 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args)
48 #else
49 #define AA_BUG_FMT(X, fmt, args...) no_printk(fmt, ##args)
50 #endif
51
52 #define AA_ERROR(fmt, args...) \
53 pr_err_ratelimited("AppArmor: " fmt, ##args)
54
55 /* Flag indicating whether initialization completed */
56 extern int apparmor_initialized;
57
58 /* fn's in lib */
59 const char *skipn_spaces(const char *str, size_t n);
60 char *aa_split_fqname(char *args, char **ns_name);
61 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
62 size_t *ns_len);
63 void aa_info_message(const char *str);
64
65 /* Security blob offsets */
66 extern struct lsm_blob_sizes apparmor_blob_sizes;
67
68 /**
69 * aa_strneq - compare null terminated @str to a non null terminated substring
70 * @str: a null terminated string
71 * @sub: a substring, not necessarily null terminated
72 * @len: length of @sub to compare
73 *
74 * The @str string must be full consumed for this to be considered a match
75 */
aa_strneq(const char * str,const char * sub,int len)76 static inline bool aa_strneq(const char *str, const char *sub, int len)
77 {
78 return !strncmp(str, sub, len) && !str[len];
79 }
80
81 /**
82 * aa_dfa_null_transition - step to next state after null character
83 * @dfa: the dfa to match against
84 * @start: the state of the dfa to start matching in
85 *
86 * aa_dfa_null_transition transitions to the next state after a null
87 * character which is not used in standard matching and is only
88 * used to separate pairs.
89 */
aa_dfa_null_transition(struct aa_dfa * dfa,aa_state_t start)90 static inline aa_state_t aa_dfa_null_transition(struct aa_dfa *dfa,
91 aa_state_t start)
92 {
93 /* the null transition only needs the string's null terminator byte */
94 return aa_dfa_next(dfa, start, 0);
95 }
96
path_mediated_fs(struct dentry * dentry)97 static inline bool path_mediated_fs(struct dentry *dentry)
98 {
99 return !(dentry->d_sb->s_flags & SB_NOUSER);
100 }
101
102 struct aa_str_table {
103 int size;
104 char **table;
105 };
106
107 void aa_free_str_table(struct aa_str_table *table);
108
109 struct counted_str {
110 struct kref count;
111 char name[];
112 };
113
114 #define str_to_counted(str) \
115 ((struct counted_str *)(str - offsetof(struct counted_str, name)))
116
117 #define __counted /* atm just a notation */
118
119 void aa_str_kref(struct kref *kref);
120 char *aa_str_alloc(int size, gfp_t gfp);
121
122
aa_get_str(__counted char * str)123 static inline __counted char *aa_get_str(__counted char *str)
124 {
125 if (str)
126 kref_get(&(str_to_counted(str)->count));
127
128 return str;
129 }
130
aa_put_str(__counted char * str)131 static inline void aa_put_str(__counted char *str)
132 {
133 if (str)
134 kref_put(&str_to_counted(str)->count, aa_str_kref);
135 }
136
137
138 /* struct aa_policy - common part of both namespaces and profiles
139 * @name: name of the object
140 * @hname - The hierarchical name
141 * @list: list policy object is on
142 * @profiles: head of the profiles list contained in the object
143 */
144 struct aa_policy {
145 const char *name;
146 __counted char *hname;
147 struct list_head list;
148 struct list_head profiles;
149 };
150
151 /**
152 * basename - find the last component of an hname
153 * @name: hname to find the base profile name component of (NOT NULL)
154 *
155 * Returns: the tail (base profile name) name component of an hname
156 */
basename(const char * hname)157 static inline const char *basename(const char *hname)
158 {
159 char *split;
160
161 hname = strim((char *)hname);
162 for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
163 hname = split + 2;
164
165 return hname;
166 }
167
168 /**
169 * __policy_find - find a policy by @name on a policy list
170 * @head: list to search (NOT NULL)
171 * @name: name to search for (NOT NULL)
172 *
173 * Requires: rcu_read_lock be held
174 *
175 * Returns: unrefcounted policy that match @name or NULL if not found
176 */
__policy_find(struct list_head * head,const char * name)177 static inline struct aa_policy *__policy_find(struct list_head *head,
178 const char *name)
179 {
180 struct aa_policy *policy;
181
182 list_for_each_entry_rcu(policy, head, list) {
183 if (!strcmp(policy->name, name))
184 return policy;
185 }
186 return NULL;
187 }
188
189 /**
190 * __policy_strn_find - find a policy that's name matches @len chars of @str
191 * @head: list to search (NOT NULL)
192 * @str: string to search for (NOT NULL)
193 * @len: length of match required
194 *
195 * Requires: rcu_read_lock be held
196 *
197 * Returns: unrefcounted policy that match @str or NULL if not found
198 *
199 * if @len == strlen(@strlen) then this is equiv to __policy_find
200 * other wise it allows searching for policy by a partial match of name
201 */
__policy_strn_find(struct list_head * head,const char * str,int len)202 static inline struct aa_policy *__policy_strn_find(struct list_head *head,
203 const char *str, int len)
204 {
205 struct aa_policy *policy;
206
207 list_for_each_entry_rcu(policy, head, list) {
208 if (aa_strneq(policy->name, str, len))
209 return policy;
210 }
211
212 return NULL;
213 }
214
215 bool aa_policy_init(struct aa_policy *policy, const char *prefix,
216 const char *name, gfp_t gfp);
217 void aa_policy_destroy(struct aa_policy *policy);
218
219
220 /*
221 * fn_label_build - abstract out the build of a label transition
222 * @L: label the transition is being computed for
223 * @P: profile parameter derived from L by this macro, can be passed to FN
224 * @GFP: memory allocation type to use
225 * @FN: fn to call for each profile transition. @P is set to the profile
226 *
227 * Returns: new label on success
228 * ERR_PTR if build @FN fails
229 * NULL if label_build fails due to low memory conditions
230 *
231 * @FN must return a label or ERR_PTR on failure. NULL is not allowed
232 */
233 #define fn_label_build(L, P, GFP, FN) \
234 ({ \
235 __label__ __do_cleanup, __done; \
236 struct aa_label *__new_; \
237 \
238 if ((L)->size > 1) { \
239 /* TODO: add cache of transitions already done */ \
240 struct label_it __i; \
241 int __j, __k, __count; \
242 DEFINE_VEC(label, __lvec); \
243 DEFINE_VEC(profile, __pvec); \
244 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \
245 __new_ = NULL; \
246 goto __done; \
247 } \
248 __j = 0; \
249 label_for_each(__i, (L), (P)) { \
250 __new_ = (FN); \
251 AA_BUG(!__new_); \
252 if (IS_ERR(__new_)) \
253 goto __do_cleanup; \
254 __lvec[__j++] = __new_; \
255 } \
256 for (__j = __count = 0; __j < (L)->size; __j++) \
257 __count += __lvec[__j]->size; \
258 if (!vec_setup(profile, __pvec, __count, (GFP))) { \
259 for (__j = __k = 0; __j < (L)->size; __j++) { \
260 label_for_each(__i, __lvec[__j], (P)) \
261 __pvec[__k++] = aa_get_profile(P); \
262 } \
263 __count -= aa_vec_unique(__pvec, __count, 0); \
264 if (__count > 1) { \
265 __new_ = aa_vec_find_or_create_label(__pvec,\
266 __count, (GFP)); \
267 /* only fails if out of Mem */ \
268 if (!__new_) \
269 __new_ = NULL; \
270 } else \
271 __new_ = aa_get_label(&__pvec[0]->label); \
272 vec_cleanup(profile, __pvec, __count); \
273 } else \
274 __new_ = NULL; \
275 __do_cleanup: \
276 vec_cleanup(label, __lvec, (L)->size); \
277 } else { \
278 (P) = labels_profile(L); \
279 __new_ = (FN); \
280 } \
281 __done: \
282 if (!__new_) \
283 AA_DEBUG("label build failed\n"); \
284 (__new_); \
285 })
286
287
288 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \
289 ({ \
290 struct aa_label *__new; \
291 if ((P)->ns != (NS)) \
292 __new = (OTHER_FN); \
293 else \
294 __new = (NS_FN); \
295 (__new); \
296 })
297
298 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \
299 ({ \
300 fn_label_build((L), (P), (GFP), \
301 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \
302 })
303
304 #endif /* __AA_LIB_H */
305