lib.h

  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
 34#define DEBUG_ALL 0x1f		/* update if new DEBUG_X added */
 35#define DEBUG_PARSE_ERROR (-1)
 36
 37#define DEBUG_ON (aa_g_debug != DEBUG_NONE)
 38#define DEBUG_ABS_ROOT (aa_g_debug & DEBUG_LABEL_ABS_ROOT)
 39
 40#define AA_DEBUG(opt, fmt, args...)					\
 41	do {								\
 42		if (aa_g_debug & opt)					\
 43			pr_warn_ratelimited("%s: " fmt, __func__, ##args); \
 44	} while (0)
 45#define AA_DEBUG_LABEL(LAB, X, fmt, args...)				\
 46do {									\
 47	if ((LAB)->flags & FLAG_DEBUG1)					\
 48		AA_DEBUG(X, fmt, args);					\
 49} while (0)
 50
 51#define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X)
 52
 53#define AA_BUG(X, args...)						    \
 54	do {								    \
 55		_Pragma("GCC diagnostic ignored \"-Wformat-zero-length\""); \
 56		AA_BUG_FMT((X), "" args);				    \
 57		_Pragma("GCC diagnostic warning \"-Wformat-zero-length\""); \
 58	} while (0)
 59#ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS
 60#define AA_BUG_FMT(X, fmt, args...)					\
 61	WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args)
 62#else
 63#define AA_BUG_FMT(X, fmt, args...)					\
 64	do {								\
 65		BUILD_BUG_ON_INVALID(X);				\
 66		no_printk(fmt, ##args);					\
 67	} while (0)
 68#endif
 69
 70int aa_parse_debug_params(const char *str);
 71int aa_print_debug_params(char *buffer);
 72
 73#define AA_ERROR(fmt, args...)						\
 74	pr_err_ratelimited("AppArmor: " fmt, ##args)
 75
 76/* Flag indicating whether initialization completed */
 77extern int apparmor_initialized;
 78
 79/* fn's in lib */
 80const char *skipn_spaces(const char *str, size_t n);
 81const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
 82			     size_t *ns_len);
 83void aa_info_message(const char *str);
 84
 85/* Security blob offsets */
 86extern struct lsm_blob_sizes apparmor_blob_sizes;
 87
 88enum reftype {
 89	REF_NS,
 90	REF_PROXY,
 91	REF_RAWDATA,
 92};
 93
 94/* common reference count used by data the shows up in aafs */
 95struct aa_common_ref {
 96	struct kref count;
 97	enum reftype reftype;
 98};
 99
100/**
101 * aa_strneq - compare null terminated @str to a non null terminated substring
102 * @str: a null terminated string
103 * @sub: a substring, not necessarily null terminated
104 * @len: length of @sub to compare
105 *
106 * The @str string must be full consumed for this to be considered a match
107 */
108static inline bool aa_strneq(const char *str, const char *sub, int len)
109{
110	return !strncmp(str, sub, len) && !str[len];
111}
112
113/**
114 * aa_dfa_null_transition - step to next state after null character
115 * @dfa: the dfa to match against
116 * @start: the state of the dfa to start matching in
117 *
118 * aa_dfa_null_transition transitions to the next state after a null
119 * character which is not used in standard matching and is only
120 * used to separate pairs.
121 */
122static inline aa_state_t aa_dfa_null_transition(struct aa_dfa *dfa,
123						aa_state_t start)
124{
125	/* the null transition only needs the string's null terminator byte */
126	return aa_dfa_next(dfa, start, 0);
127}
128
129static inline bool path_mediated_fs(struct dentry *dentry)
130{
131	return !(dentry->d_sb->s_flags & SB_NOUSER);
132}
133
134struct aa_str_table {
135	int size;
136	char **table;
137};
138
139void aa_free_str_table(struct aa_str_table *table);
140bool aa_resize_str_table(struct aa_str_table *t, int newsize, gfp_t gfp);
141
142struct counted_str {
143	struct kref count;
144	char name[];
145};
146
147#define str_to_counted(str) \
148	((struct counted_str *)(str - offsetof(struct counted_str, name)))
149
150#define __counted	/* atm just a notation */
151
152void aa_str_kref(struct kref *kref);
153char *aa_str_alloc(int size, gfp_t gfp);
154
155
156static inline __counted char *aa_get_str(__counted char *str)
157{
158	if (str)
159		kref_get(&(str_to_counted(str)->count));
160
161	return str;
162}
163
164static inline void aa_put_str(__counted char *str)
165{
166	if (str)
167		kref_put(&str_to_counted(str)->count, aa_str_kref);
168}
169
170
171/* struct aa_policy - common part of both namespaces and profiles
172 * @name: name of the object
173 * @hname - The hierarchical name
174 * @list: list policy object is on
175 * @profiles: head of the profiles list contained in the object
176 */
177struct aa_policy {
178	const char *name;
179	__counted char *hname;
180	struct list_head list;
181	struct list_head profiles;
182};
183
184/**
185 * basename - find the last component of an hname
186 * @hname: hname to find the base profile name component of  (NOT NULL)
187 *
188 * Returns: the tail (base profile name) name component of an hname
189 */
190static inline const char *basename(const char *hname)
191{
192	char *split;
193
194	hname = strim((char *)hname);
195	for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
196		hname = split + 2;
197
198	return hname;
199}
200
201/**
202 * __policy_find - find a policy by @name on a policy list
203 * @head: list to search  (NOT NULL)
204 * @name: name to search for  (NOT NULL)
205 *
206 * Requires: rcu_read_lock be held
207 *
208 * Returns: unrefcounted policy that match @name or NULL if not found
209 */
210static inline struct aa_policy *__policy_find(struct list_head *head,
211					      const char *name)
212{
213	struct aa_policy *policy;
214
215	list_for_each_entry_rcu(policy, head, list) {
216		if (!strcmp(policy->name, name))
217			return policy;
218	}
219	return NULL;
220}
221
222/**
223 * __policy_strn_find - find a policy that's name matches @len chars of @str
224 * @head: list to search  (NOT NULL)
225 * @str: string to search for  (NOT NULL)
226 * @len: length of match required
227 *
228 * Requires: rcu_read_lock be held
229 *
230 * Returns: unrefcounted policy that match @str or NULL if not found
231 *
232 * if @len == strlen(@strlen) then this is equiv to __policy_find
233 * other wise it allows searching for policy by a partial match of name
234 */
235static inline struct aa_policy *__policy_strn_find(struct list_head *head,
236					    const char *str, int len)
237{
238	struct aa_policy *policy;
239
240	list_for_each_entry_rcu(policy, head, list) {
241		if (aa_strneq(policy->name, str, len))
242			return policy;
243	}
244
245	return NULL;
246}
247
248bool aa_policy_init(struct aa_policy *policy, const char *prefix,
249		    const char *name, gfp_t gfp);
250void aa_policy_destroy(struct aa_policy *policy);
251
252
253/*
254 * fn_label_build - abstract out the build of a label transition
255 * @L: label the transition is being computed for
256 * @P: profile parameter derived from L by this macro, can be passed to FN
257 * @GFP: memory allocation type to use
258 * @FN: fn to call for each profile transition. @P is set to the profile
259 *
260 * Returns: new label on success
261 *          ERR_PTR if build @FN fails
262 *          NULL if label_build fails due to low memory conditions
263 *
264 * @FN must return a label or ERR_PTR on failure. NULL is not allowed
265 */
266#define fn_label_build(L, P, GFP, FN)					\
267({									\
268	__label__ __do_cleanup, __done;					\
269	struct aa_label *__new_;					\
270									\
271	if ((L)->size > 1) {						\
272		/* TODO: add cache of transitions already done */	\
273		struct label_it __i;					\
274		int __j, __k, __count;					\
275		DEFINE_VEC(label, __lvec);				\
276		DEFINE_VEC(profile, __pvec);				\
277		if (vec_setup(label, __lvec, (L)->size, (GFP)))	{	\
278			__new_ = NULL;					\
279			goto __done;					\
280		}							\
281		__j = 0;						\
282		label_for_each(__i, (L), (P)) {				\
283			__new_ = (FN);					\
284			AA_BUG(!__new_);				\
285			if (IS_ERR(__new_))				\
286				goto __do_cleanup;			\
287			__lvec[__j++] = __new_;				\
288		}							\
289		for (__j = __count = 0; __j < (L)->size; __j++)		\
290			__count += __lvec[__j]->size;			\
291		if (!vec_setup(profile, __pvec, __count, (GFP))) {	\
292			for (__j = __k = 0; __j < (L)->size; __j++) {	\
293				label_for_each(__i, __lvec[__j], (P))	\
294					__pvec[__k++] = aa_get_profile(P); \
295			}						\
296			__count -= aa_vec_unique(__pvec, __count, 0);	\
297			if (__count > 1) {				\
298				__new_ = aa_vec_find_or_create_label(__pvec,\
299						     __count, (GFP));	\
300				/* only fails if out of Mem */		\
301				if (!__new_)				\
302					__new_ = NULL;			\
303			} else						\
304				__new_ = aa_get_label(&__pvec[0]->label); \
305			vec_cleanup(profile, __pvec, __count);		\
306		} else							\
307			__new_ = NULL;					\
308__do_cleanup:								\
309		vec_cleanup(label, __lvec, (L)->size);			\
310	} else {							\
311		(P) = labels_profile(L);				\
312		__new_ = (FN);						\
313	}								\
314__done:									\
315	if (!__new_)							\
316		AA_DEBUG(DEBUG_LABEL, "label build failed\n");		\
317	(__new_);							\
318})
319
320
321#define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN)			\
322({									\
323	struct aa_label *__new;						\
324	if ((P)->ns != (NS))						\
325		__new = (OTHER_FN);					\
326	else								\
327		__new = (NS_FN);					\
328	(__new);							\
329})
330
331#define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN)		\
332({									\
333	fn_label_build((L), (P), (GFP),					\
334		__fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \
335})
336
337#endif /* __AA_LIB_H */