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,unsigned int start)90 static inline unsigned int aa_dfa_null_transition(struct aa_dfa *dfa,
91 unsigned int 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
103 struct counted_str {
104 struct kref count;
105 char name[];
106 };
107
108 #define str_to_counted(str) \
109 ((struct counted_str *)(str - offsetof(struct counted_str, name)))
110
111 #define __counted /* atm just a notation */
112
113 void aa_str_kref(struct kref *kref);
114 char *aa_str_alloc(int size, gfp_t gfp);
115
116
aa_get_str(__counted char * str)117 static inline __counted char *aa_get_str(__counted char *str)
118 {
119 if (str)
120 kref_get(&(str_to_counted(str)->count));
121
122 return str;
123 }
124
aa_put_str(__counted char * str)125 static inline void aa_put_str(__counted char *str)
126 {
127 if (str)
128 kref_put(&str_to_counted(str)->count, aa_str_kref);
129 }
130
131
132 /* struct aa_policy - common part of both namespaces and profiles
133 * @name: name of the object
134 * @hname - The hierarchical name
135 * @list: list policy object is on
136 * @profiles: head of the profiles list contained in the object
137 */
138 struct aa_policy {
139 const char *name;
140 __counted char *hname;
141 struct list_head list;
142 struct list_head profiles;
143 };
144
145 /**
146 * basename - find the last component of an hname
147 * @name: hname to find the base profile name component of (NOT NULL)
148 *
149 * Returns: the tail (base profile name) name component of an hname
150 */
basename(const char * hname)151 static inline const char *basename(const char *hname)
152 {
153 char *split;
154
155 hname = strim((char *)hname);
156 for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
157 hname = split + 2;
158
159 return hname;
160 }
161
162 /**
163 * __policy_find - find a policy by @name on a policy list
164 * @head: list to search (NOT NULL)
165 * @name: name to search for (NOT NULL)
166 *
167 * Requires: rcu_read_lock be held
168 *
169 * Returns: unrefcounted policy that match @name or NULL if not found
170 */
__policy_find(struct list_head * head,const char * name)171 static inline struct aa_policy *__policy_find(struct list_head *head,
172 const char *name)
173 {
174 struct aa_policy *policy;
175
176 list_for_each_entry_rcu(policy, head, list) {
177 if (!strcmp(policy->name, name))
178 return policy;
179 }
180 return NULL;
181 }
182
183 /**
184 * __policy_strn_find - find a policy that's name matches @len chars of @str
185 * @head: list to search (NOT NULL)
186 * @str: string to search for (NOT NULL)
187 * @len: length of match required
188 *
189 * Requires: rcu_read_lock be held
190 *
191 * Returns: unrefcounted policy that match @str or NULL if not found
192 *
193 * if @len == strlen(@strlen) then this is equiv to __policy_find
194 * other wise it allows searching for policy by a partial match of name
195 */
__policy_strn_find(struct list_head * head,const char * str,int len)196 static inline struct aa_policy *__policy_strn_find(struct list_head *head,
197 const char *str, int len)
198 {
199 struct aa_policy *policy;
200
201 list_for_each_entry_rcu(policy, head, list) {
202 if (aa_strneq(policy->name, str, len))
203 return policy;
204 }
205
206 return NULL;
207 }
208
209 bool aa_policy_init(struct aa_policy *policy, const char *prefix,
210 const char *name, gfp_t gfp);
211 void aa_policy_destroy(struct aa_policy *policy);
212
213
214 /*
215 * fn_label_build - abstract out the build of a label transition
216 * @L: label the transition is being computed for
217 * @P: profile parameter derived from L by this macro, can be passed to FN
218 * @GFP: memory allocation type to use
219 * @FN: fn to call for each profile transition. @P is set to the profile
220 *
221 * Returns: new label on success
222 * ERR_PTR if build @FN fails
223 * NULL if label_build fails due to low memory conditions
224 *
225 * @FN must return a label or ERR_PTR on failure. NULL is not allowed
226 */
227 #define fn_label_build(L, P, GFP, FN) \
228 ({ \
229 __label__ __cleanup, __done; \
230 struct aa_label *__new_; \
231 \
232 if ((L)->size > 1) { \
233 /* TODO: add cache of transitions already done */ \
234 struct label_it __i; \
235 int __j, __k, __count; \
236 DEFINE_VEC(label, __lvec); \
237 DEFINE_VEC(profile, __pvec); \
238 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \
239 __new_ = NULL; \
240 goto __done; \
241 } \
242 __j = 0; \
243 label_for_each(__i, (L), (P)) { \
244 __new_ = (FN); \
245 AA_BUG(!__new_); \
246 if (IS_ERR(__new_)) \
247 goto __cleanup; \
248 __lvec[__j++] = __new_; \
249 } \
250 for (__j = __count = 0; __j < (L)->size; __j++) \
251 __count += __lvec[__j]->size; \
252 if (!vec_setup(profile, __pvec, __count, (GFP))) { \
253 for (__j = __k = 0; __j < (L)->size; __j++) { \
254 label_for_each(__i, __lvec[__j], (P)) \
255 __pvec[__k++] = aa_get_profile(P); \
256 } \
257 __count -= aa_vec_unique(__pvec, __count, 0); \
258 if (__count > 1) { \
259 __new_ = aa_vec_find_or_create_label(__pvec,\
260 __count, (GFP)); \
261 /* only fails if out of Mem */ \
262 if (!__new_) \
263 __new_ = NULL; \
264 } else \
265 __new_ = aa_get_label(&__pvec[0]->label); \
266 vec_cleanup(profile, __pvec, __count); \
267 } else \
268 __new_ = NULL; \
269 __cleanup: \
270 vec_cleanup(label, __lvec, (L)->size); \
271 } else { \
272 (P) = labels_profile(L); \
273 __new_ = (FN); \
274 } \
275 __done: \
276 if (!__new_) \
277 AA_DEBUG("label build failed\n"); \
278 (__new_); \
279 })
280
281
282 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \
283 ({ \
284 struct aa_label *__new; \
285 if ((P)->ns != (NS)) \
286 __new = (OTHER_FN); \
287 else \
288 __new = (NS_FN); \
289 (__new); \
290 })
291
292 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \
293 ({ \
294 fn_label_build((L), (P), (GFP), \
295 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \
296 })
297
298 #endif /* __AA_LIB_H */
299
