1 /* 2 * AppArmor security module 3 * 4 * This file contains AppArmor lib definitions 5 * 6 * 2017 Canonical Ltd. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation, version 2 of the 11 * License. 12 */ 13 14 #ifndef __AA_LIB_H 15 #define __AA_LIB_H 16 17 #include <linux/slab.h> 18 #include <linux/fs.h> 19 20 #include "match.h" 21 22 /* Provide our own test for whether a write lock is held for asserts 23 * this is because on none SMP systems write_can_lock will always 24 * resolve to true, which is what you want for code making decisions 25 * based on it, but wrong for asserts checking that the lock is held 26 */ 27 #ifdef CONFIG_SMP 28 #define write_is_locked(X) !write_can_lock(X) 29 #else 30 #define write_is_locked(X) (1) 31 #endif /* CONFIG_SMP */ 32 33 /* 34 * DEBUG remains global (no per profile flag) since it is mostly used in sysctl 35 * which is not related to profile accesses. 36 */ 37 38 #define DEBUG_ON (aa_g_debug) 39 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args) 40 #define AA_DEBUG(fmt, args...) \ 41 do { \ 42 if (DEBUG_ON) \ 43 pr_debug_ratelimited("AppArmor: " fmt, ##args); \ 44 } while (0) 45 46 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X) 47 48 #define AA_BUG(X, args...) AA_BUG_FMT((X), "" args) 49 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS 50 #define AA_BUG_FMT(X, fmt, args...) \ 51 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args) 52 #else 53 #define AA_BUG_FMT(X, fmt, args...) 54 #endif 55 56 #define AA_ERROR(fmt, args...) \ 57 pr_err_ratelimited("AppArmor: " fmt, ##args) 58 59 /* Flag indicating whether initialization completed */ 60 extern int apparmor_initialized; 61 62 /* fn's in lib */ 63 const char *skipn_spaces(const char *str, size_t n); 64 char *aa_split_fqname(char *args, char **ns_name); 65 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name, 66 size_t *ns_len); 67 void aa_info_message(const char *str); 68 69 /** 70 * aa_strneq - compare null terminated @str to a non null terminated substring 71 * @str: a null terminated string 72 * @sub: a substring, not necessarily null terminated 73 * @len: length of @sub to compare 74 * 75 * The @str string must be full consumed for this to be considered a match 76 */ 77 static inline bool aa_strneq(const char *str, const char *sub, int len) 78 { 79 return !strncmp(str, sub, len) && !str[len]; 80 } 81 82 /** 83 * aa_dfa_null_transition - step to next state after null character 84 * @dfa: the dfa to match against 85 * @start: the state of the dfa to start matching in 86 * 87 * aa_dfa_null_transition transitions to the next state after a null 88 * character which is not used in standard matching and is only 89 * used to separate pairs. 90 */ 91 static inline unsigned int aa_dfa_null_transition(struct aa_dfa *dfa, 92 unsigned int start) 93 { 94 /* the null transition only needs the string's null terminator byte */ 95 return aa_dfa_next(dfa, start, 0); 96 } 97 98 static inline bool path_mediated_fs(struct dentry *dentry) 99 { 100 return !(dentry->d_sb->s_flags & MS_NOUSER); 101 } 102 103 104 struct counted_str { 105 struct kref count; 106 char name[]; 107 }; 108 109 #define str_to_counted(str) \ 110 ((struct counted_str *)(str - offsetof(struct counted_str, name))) 111 112 #define __counted /* atm just a notation */ 113 114 void aa_str_kref(struct kref *kref); 115 char *aa_str_alloc(int size, gfp_t gfp); 116 117 118 static inline __counted char *aa_get_str(__counted char *str) 119 { 120 if (str) 121 kref_get(&(str_to_counted(str)->count)); 122 123 return str; 124 } 125 126 static inline void aa_put_str(__counted char *str) 127 { 128 if (str) 129 kref_put(&str_to_counted(str)->count, aa_str_kref); 130 } 131 132 133 /* struct aa_policy - common part of both namespaces and profiles 134 * @name: name of the object 135 * @hname - The hierarchical name 136 * @list: list policy object is on 137 * @profiles: head of the profiles list contained in the object 138 */ 139 struct aa_policy { 140 const char *name; 141 __counted char *hname; 142 struct list_head list; 143 struct list_head profiles; 144 }; 145 146 /** 147 * basename - find the last component of an hname 148 * @name: hname to find the base profile name component of (NOT NULL) 149 * 150 * Returns: the tail (base profile name) name component of an hname 151 */ 152 static inline const char *basename(const char *hname) 153 { 154 char *split; 155 156 hname = strim((char *)hname); 157 for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) 158 hname = split + 2; 159 160 return hname; 161 } 162 163 /** 164 * __policy_find - find a policy by @name on a policy list 165 * @head: list to search (NOT NULL) 166 * @name: name to search for (NOT NULL) 167 * 168 * Requires: rcu_read_lock be held 169 * 170 * Returns: unrefcounted policy that match @name or NULL if not found 171 */ 172 static inline struct aa_policy *__policy_find(struct list_head *head, 173 const char *name) 174 { 175 struct aa_policy *policy; 176 177 list_for_each_entry_rcu(policy, head, list) { 178 if (!strcmp(policy->name, name)) 179 return policy; 180 } 181 return NULL; 182 } 183 184 /** 185 * __policy_strn_find - find a policy that's name matches @len chars of @str 186 * @head: list to search (NOT NULL) 187 * @str: string to search for (NOT NULL) 188 * @len: length of match required 189 * 190 * Requires: rcu_read_lock be held 191 * 192 * Returns: unrefcounted policy that match @str or NULL if not found 193 * 194 * if @len == strlen(@strlen) then this is equiv to __policy_find 195 * other wise it allows searching for policy by a partial match of name 196 */ 197 static inline struct aa_policy *__policy_strn_find(struct list_head *head, 198 const char *str, int len) 199 { 200 struct aa_policy *policy; 201 202 list_for_each_entry_rcu(policy, head, list) { 203 if (aa_strneq(policy->name, str, len)) 204 return policy; 205 } 206 207 return NULL; 208 } 209 210 bool aa_policy_init(struct aa_policy *policy, const char *prefix, 211 const char *name, gfp_t gfp); 212 void aa_policy_destroy(struct aa_policy *policy); 213 214 215 /* 216 * fn_label_build - abstract out the build of a label transition 217 * @L: label the transition is being computed for 218 * @P: profile parameter derived from L by this macro, can be passed to FN 219 * @GFP: memory allocation type to use 220 * @FN: fn to call for each profile transition. @P is set to the profile 221 * 222 * Returns: new label on success 223 * ERR_PTR if build @FN fails 224 * NULL if label_build fails due to low memory conditions 225 * 226 * @FN must return a label or ERR_PTR on failure. NULL is not allowed 227 */ 228 #define fn_label_build(L, P, GFP, FN) \ 229 ({ \ 230 __label__ __cleanup, __done; \ 231 struct aa_label *__new_; \ 232 \ 233 if ((L)->size > 1) { \ 234 /* TODO: add cache of transitions already done */ \ 235 struct label_it __i; \ 236 int __j, __k, __count; \ 237 DEFINE_VEC(label, __lvec); \ 238 DEFINE_VEC(profile, __pvec); \ 239 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \ 240 __new_ = NULL; \ 241 goto __done; \ 242 } \ 243 __j = 0; \ 244 label_for_each(__i, (L), (P)) { \ 245 __new_ = (FN); \ 246 AA_BUG(!__new_); \ 247 if (IS_ERR(__new_)) \ 248 goto __cleanup; \ 249 __lvec[__j++] = __new_; \ 250 } \ 251 for (__j = __count = 0; __j < (L)->size; __j++) \ 252 __count += __lvec[__j]->size; \ 253 if (!vec_setup(profile, __pvec, __count, (GFP))) { \ 254 for (__j = __k = 0; __j < (L)->size; __j++) { \ 255 label_for_each(__i, __lvec[__j], (P)) \ 256 __pvec[__k++] = aa_get_profile(P); \ 257 } \ 258 __count -= aa_vec_unique(__pvec, __count, 0); \ 259 if (__count > 1) { \ 260 __new_ = aa_vec_find_or_create_label(__pvec,\ 261 __count, (GFP)); \ 262 /* only fails if out of Mem */ \ 263 if (!__new_) \ 264 __new_ = NULL; \ 265 } else \ 266 __new_ = aa_get_label(&__pvec[0]->label); \ 267 vec_cleanup(profile, __pvec, __count); \ 268 } else \ 269 __new_ = NULL; \ 270 __cleanup: \ 271 vec_cleanup(label, __lvec, (L)->size); \ 272 } else { \ 273 (P) = labels_profile(L); \ 274 __new_ = (FN); \ 275 } \ 276 __done: \ 277 if (!__new_) \ 278 AA_DEBUG("label build failed\n"); \ 279 (__new_); \ 280 }) 281 282 283 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \ 284 ({ \ 285 struct aa_label *__new; \ 286 if ((P)->ns != (NS)) \ 287 __new = (OTHER_FN); \ 288 else \ 289 __new = (NS_FN); \ 290 (__new); \ 291 }) 292 293 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \ 294 ({ \ 295 fn_label_build((L), (P), (GFP), \ 296 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \ 297 }) 298 299 #endif /* __AA_LIB_H */ 300