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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
19extern 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#define DEBUG_UNPACK 0x20
34#define DEBUG_TAGS 0x40
35
36#define DEBUG_ALL 0x7f /* update if new DEBUG_X added */
37#define DEBUG_PARSE_ERROR (-1)
38
39#define DEBUG_ON (aa_g_debug != DEBUG_NONE)
40#define DEBUG_ABS_ROOT (aa_g_debug & DEBUG_LABEL_ABS_ROOT)
41
42#define AA_DEBUG(opt, fmt, args...) \
43 do { \
44 if (aa_g_debug & opt) \
45 pr_warn_ratelimited("%s: " fmt, __func__, ##args); \
46 } while (0)
47#define AA_DEBUG_LABEL(LAB, X, fmt, args...) \
48do { \
49 if ((LAB)->flags & FLAG_DEBUG1) \
50 AA_DEBUG(X, fmt, ##args); \
51} while (0)
52
53#define AA_DEBUG_PROFILE(PROF, X, fmt...) AA_DEBUG_LABEL(&(PROF)->label, X, ##fmt)
54
55#define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X)
56
57#define AA_BUG(X, args...) \
58 do { \
59 _Pragma("GCC diagnostic ignored \"-Wformat-zero-length\""); \
60 AA_BUG_FMT((X), "" args); \
61 _Pragma("GCC diagnostic warning \"-Wformat-zero-length\""); \
62 } while (0)
63#ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS
64#define AA_BUG_FMT(X, fmt, args...) \
65 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args)
66#else
67#define AA_BUG_FMT(X, fmt, args...) \
68 do { \
69 BUILD_BUG_ON_INVALID(X); \
70 no_printk(fmt, ##args); \
71 } while (0)
72#endif
73
74int aa_parse_debug_params(const char *str);
75int aa_print_debug_params(char *buffer);
76
77#define AA_ERROR(fmt, args...) \
78 pr_err_ratelimited("AppArmor: " fmt, ##args)
79
80/* Flag indicating whether initialization completed */
81extern int apparmor_initialized;
82
83/* semantic split of scope and view */
84#define aa_in_scope(SUBJ, OBJ) \
85 aa_ns_visible(SUBJ, OBJ, false)
86
87#define aa_in_view(SUBJ, OBJ) \
88 aa_ns_visible(SUBJ, OBJ, true)
89
90#define label_for_each_in_scope(I, NS, L, P) \
91 label_for_each_in_ns(I, NS, L, P)
92
93#define fn_for_each_in_scope(L, P, FN) \
94 fn_for_each_in_ns(L, P, FN)
95
96/* fn's in lib */
97const char *skipn_spaces(const char *str, size_t n);
98const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
99 size_t *ns_len);
100void aa_info_message(const char *str);
101
102/* Security blob offsets */
103extern struct lsm_blob_sizes apparmor_blob_sizes;
104
105enum reftype {
106 REF_NS,
107 REF_PROXY,
108 REF_RAWDATA,
109};
110
111/* common reference count used by data the shows up in aafs */
112struct aa_common_ref {
113 struct kref count;
114 enum reftype reftype;
115};
116
117/**
118 * aa_strneq - compare null terminated @str to a non null terminated substring
119 * @str: a null terminated string
120 * @sub: a substring, not necessarily null terminated
121 * @len: length of @sub to compare
122 *
123 * The @str string must be full consumed for this to be considered a match
124 */
125static inline bool aa_strneq(const char *str, const char *sub, int len)
126{
127 return !strncmp(str, sub, len) && !str[len];
128}
129
130/**
131 * aa_dfa_null_transition - step to next state after null character
132 * @dfa: the dfa to match against
133 * @start: the state of the dfa to start matching in
134 *
135 * aa_dfa_null_transition transitions to the next state after a null
136 * character which is not used in standard matching and is only
137 * used to separate pairs.
138 */
139static inline aa_state_t aa_dfa_null_transition(const struct aa_dfa *dfa,
140 aa_state_t start)
141{
142 /* the null transition only needs the string's null terminator byte */
143 return aa_dfa_next(dfa, start, 0);
144}
145
146static inline bool path_mediated_fs(struct dentry *dentry)
147{
148 return !(dentry->d_sb->s_flags & SB_NOUSER);
149}
150
151struct aa_str_table_ent {
152 int count;
153 int size;
154 char *strs;
155};
156
157struct aa_str_table {
158 int size;
159 struct aa_str_table_ent *table;
160};
161
162bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp);
163void aa_destroy_str_table(struct aa_str_table *table);
164
165struct counted_str {
166 struct kref count;
167 char name[];
168};
169
170#define str_to_counted(str) \
171 ((struct counted_str *)(str - offsetof(struct counted_str, name)))
172
173#define __counted /* atm just a notation */
174
175void aa_str_kref(struct kref *kref);
176char *aa_str_alloc(int size, gfp_t gfp);
177
178
179static inline __counted char *aa_get_str(__counted char *str)
180{
181 if (str)
182 kref_get(&(str_to_counted(str)->count));
183
184 return str;
185}
186
187static inline void aa_put_str(__counted char *str)
188{
189 if (str)
190 kref_put(&str_to_counted(str)->count, aa_str_kref);
191}
192
193
194/* struct aa_policy - common part of both namespaces and profiles
195 * @name: name of the object
196 * @hname - The hierarchical name
197 * @list: list policy object is on
198 * @profiles: head of the profiles list contained in the object
199 */
200struct aa_policy {
201 const char *name;
202 __counted char *hname;
203 struct list_head list;
204 struct list_head profiles;
205};
206
207/**
208 * basename - find the last component of an hname
209 * @hname: hname to find the base profile name component of (NOT NULL)
210 *
211 * Returns: the tail (base profile name) name component of an hname
212 */
213static inline const char *basename(const char *hname)
214{
215 char *split;
216
217 hname = strim((char *)hname);
218 for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
219 hname = split + 2;
220
221 return hname;
222}
223
224/**
225 * __policy_find - find a policy by @name on a policy list
226 * @head: list to search (NOT NULL)
227 * @name: name to search for (NOT NULL)
228 *
229 * Requires: rcu_read_lock be held
230 *
231 * Returns: unrefcounted policy that match @name or NULL if not found
232 */
233static inline struct aa_policy *__policy_find(struct list_head *head,
234 const char *name)
235{
236 struct aa_policy *policy;
237
238 list_for_each_entry_rcu(policy, head, list) {
239 if (!strcmp(policy->name, name))
240 return policy;
241 }
242 return NULL;
243}
244
245/**
246 * __policy_strn_find - find a policy that's name matches @len chars of @str
247 * @head: list to search (NOT NULL)
248 * @str: string to search for (NOT NULL)
249 * @len: length of match required
250 *
251 * Requires: rcu_read_lock be held
252 *
253 * Returns: unrefcounted policy that match @str or NULL if not found
254 *
255 * if @len == strlen(@strlen) then this is equiv to __policy_find
256 * other wise it allows searching for policy by a partial match of name
257 */
258static inline struct aa_policy *__policy_strn_find(struct list_head *head,
259 const char *str, int len)
260{
261 struct aa_policy *policy;
262
263 list_for_each_entry_rcu(policy, head, list) {
264 if (aa_strneq(policy->name, str, len))
265 return policy;
266 }
267
268 return NULL;
269}
270
271bool aa_policy_init(struct aa_policy *policy, const char *prefix,
272 const char *name, gfp_t gfp);
273void aa_policy_destroy(struct aa_policy *policy);
274
275
276/*
277 * fn_label_build - abstract out the build of a label transition
278 * @L: label the transition is being computed for
279 * @P: profile parameter derived from L by this macro, can be passed to FN
280 * @GFP: memory allocation type to use
281 * @FN: fn to call for each profile transition. @P is set to the profile
282 *
283 * Returns: new label on success
284 * NULL if all callbacks decline to specify a transition
285 * ERR_PTR if build @FN fails
286 *
287 * @FN must return a label or ERR_PTR on failure.
288 */
289#define fn_label_build(L, P, GFP, FN) \
290({ \
291 __label__ __do_cleanup, __done; \
292 struct aa_label *__new_ = NULL; \
293 \
294 if ((L)->size > 1) { \
295 /* TODO: add cache of transitions already done */ \
296 struct label_it __i; \
297 int __j, __k, __count; \
298 DEFINE_VEC(label, __lvec); \
299 DEFINE_VEC(profile, __pvec); \
300 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \
301 __new_ = ERR_PTR(-ENOMEM); \
302 goto __done; \
303 } \
304 __j = 0; \
305 label_for_each(__i, (L), (P)) { \
306 __new_ = (FN); \
307 if (!__new_) \
308 continue; \
309 if (IS_ERR(__new_)) \
310 goto __do_cleanup; \
311 __lvec[__j++] = __new_; \
312 } \
313 if (__j == 0) \
314 /* no components adding to build */ \
315 goto __do_cleanup; \
316 for (__j = __count = 0; __j < (L)->size; __j++) \
317 __count += __lvec[__j]->size; \
318 if (!vec_setup(profile, __pvec, __count, (GFP))) { \
319 for (__j = __k = 0; __j < (L)->size; __j++) { \
320 label_for_each(__i, __lvec[__j], (P)) \
321 __pvec[__k++] = aa_get_profile(P); \
322 } \
323 __count -= aa_vec_unique(__pvec, __count, 0); \
324 if (__count > 1) { \
325 __new_ = aa_vec_find_or_create_label(__pvec,\
326 __count, (GFP)); \
327 if (!__new_) \
328 __new_ = ERR_PTR(-ENOMEM); \
329 } else \
330 __new_ = aa_get_label(&__pvec[0]->label); \
331 vec_cleanup(profile, __pvec, __count); \
332 } else \
333 __new_ = ERR_PTR(-ENOMEM); \
334__do_cleanup: \
335 vec_cleanup(label, __lvec, (L)->size); \
336 } else { \
337 (P) = labels_profile(L); \
338 __new_ = (FN); \
339 } \
340__done: \
341 if (IS_ERR(__new_)) \
342 AA_DEBUG(DEBUG_LABEL, "label build failed %ld\n", PTR_ERR(__new_)); \
343 (__new_); \
344})
345
346
347#define __fn_build_in_scope(NS, P, NS_FN, OTHER_FN) \
348({ \
349 struct aa_label *__new; \
350 if ((P)->ns != (NS)) \
351 __new = (OTHER_FN); \
352 else \
353 __new = (NS_FN); \
354 (__new); \
355})
356
357#define fn_label_build_in_scope(L, P, GFP, NS_FN, OTHER_FN) \
358({ \
359 fn_label_build((L), (P), (GFP), \
360 __fn_build_in_scope(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \
361})
362
363#endif /* __AA_LIB_H */