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