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 /* 23 * DEBUG remains global (no per profile flag) since it is mostly used in sysctl 24 * which is not related to profile accesses. 25 */ 26 27 #define DEBUG_ON (aa_g_debug) 28 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args) 29 #define AA_DEBUG(fmt, args...) \ 30 do { \ 31 if (DEBUG_ON) \ 32 pr_debug_ratelimited("AppArmor: " fmt, ##args); \ 33 } while (0) 34 35 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X) 36 37 #define AA_BUG(X, args...) AA_BUG_FMT((X), "" args) 38 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS 39 #define AA_BUG_FMT(X, fmt, args...) \ 40 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args) 41 #else 42 #define AA_BUG_FMT(X, fmt, args...) 43 #endif 44 45 #define AA_ERROR(fmt, args...) \ 46 pr_err_ratelimited("AppArmor: " fmt, ##args) 47 48 /* Flag indicating whether initialization completed */ 49 extern int apparmor_initialized; 50 51 /* fn's in lib */ 52 const char *skipn_spaces(const char *str, size_t n); 53 char *aa_split_fqname(char *args, char **ns_name); 54 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name, 55 size_t *ns_len); 56 void aa_info_message(const char *str); 57 58 /** 59 * aa_strneq - compare null terminated @str to a non null terminated substring 60 * @str: a null terminated string 61 * @sub: a substring, not necessarily null terminated 62 * @len: length of @sub to compare 63 * 64 * The @str string must be full consumed for this to be considered a match 65 */ 66 static inline bool aa_strneq(const char *str, const char *sub, int len) 67 { 68 return !strncmp(str, sub, len) && !str[len]; 69 } 70 71 /** 72 * aa_dfa_null_transition - step to next state after null character 73 * @dfa: the dfa to match against 74 * @start: the state of the dfa to start matching in 75 * 76 * aa_dfa_null_transition transitions to the next state after a null 77 * character which is not used in standard matching and is only 78 * used to separate pairs. 79 */ 80 static inline unsigned int aa_dfa_null_transition(struct aa_dfa *dfa, 81 unsigned int start) 82 { 83 /* the null transition only needs the string's null terminator byte */ 84 return aa_dfa_next(dfa, start, 0); 85 } 86 87 static inline bool path_mediated_fs(struct dentry *dentry) 88 { 89 return !(dentry->d_sb->s_flags & MS_NOUSER); 90 } 91 92 93 struct counted_str { 94 struct kref count; 95 char name[]; 96 }; 97 98 #define str_to_counted(str) \ 99 ((struct counted_str *)(str - offsetof(struct counted_str, name))) 100 101 #define __counted /* atm just a notation */ 102 103 void aa_str_kref(struct kref *kref); 104 char *aa_str_alloc(int size, gfp_t gfp); 105 106 107 static inline __counted char *aa_get_str(__counted char *str) 108 { 109 if (str) 110 kref_get(&(str_to_counted(str)->count)); 111 112 return str; 113 } 114 115 static inline void aa_put_str(__counted char *str) 116 { 117 if (str) 118 kref_put(&str_to_counted(str)->count, aa_str_kref); 119 } 120 121 122 /* struct aa_policy - common part of both namespaces and profiles 123 * @name: name of the object 124 * @hname - The hierarchical name 125 * @list: list policy object is on 126 * @profiles: head of the profiles list contained in the object 127 */ 128 struct aa_policy { 129 const char *name; 130 __counted char *hname; 131 struct list_head list; 132 struct list_head profiles; 133 }; 134 135 /** 136 * basename - find the last component of an hname 137 * @name: hname to find the base profile name component of (NOT NULL) 138 * 139 * Returns: the tail (base profile name) name component of an hname 140 */ 141 static inline const char *basename(const char *hname) 142 { 143 char *split; 144 145 hname = strim((char *)hname); 146 for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) 147 hname = split + 2; 148 149 return hname; 150 } 151 152 /** 153 * __policy_find - find a policy by @name on a policy list 154 * @head: list to search (NOT NULL) 155 * @name: name to search for (NOT NULL) 156 * 157 * Requires: rcu_read_lock be held 158 * 159 * Returns: unrefcounted policy that match @name or NULL if not found 160 */ 161 static inline struct aa_policy *__policy_find(struct list_head *head, 162 const char *name) 163 { 164 struct aa_policy *policy; 165 166 list_for_each_entry_rcu(policy, head, list) { 167 if (!strcmp(policy->name, name)) 168 return policy; 169 } 170 return NULL; 171 } 172 173 /** 174 * __policy_strn_find - find a policy that's name matches @len chars of @str 175 * @head: list to search (NOT NULL) 176 * @str: string to search for (NOT NULL) 177 * @len: length of match required 178 * 179 * Requires: rcu_read_lock be held 180 * 181 * Returns: unrefcounted policy that match @str or NULL if not found 182 * 183 * if @len == strlen(@strlen) then this is equiv to __policy_find 184 * other wise it allows searching for policy by a partial match of name 185 */ 186 static inline struct aa_policy *__policy_strn_find(struct list_head *head, 187 const char *str, int len) 188 { 189 struct aa_policy *policy; 190 191 list_for_each_entry_rcu(policy, head, list) { 192 if (aa_strneq(policy->name, str, len)) 193 return policy; 194 } 195 196 return NULL; 197 } 198 199 bool aa_policy_init(struct aa_policy *policy, const char *prefix, 200 const char *name, gfp_t gfp); 201 void aa_policy_destroy(struct aa_policy *policy); 202 203 204 /* 205 * fn_label_build - abstract out the build of a label transition 206 * @L: label the transition is being computed for 207 * @P: profile parameter derived from L by this macro, can be passed to FN 208 * @GFP: memory allocation type to use 209 * @FN: fn to call for each profile transition. @P is set to the profile 210 * 211 * Returns: new label on success 212 * ERR_PTR if build @FN fails 213 * NULL if label_build fails due to low memory conditions 214 * 215 * @FN must return a label or ERR_PTR on failure. NULL is not allowed 216 */ 217 #define fn_label_build(L, P, GFP, FN) \ 218 ({ \ 219 __label__ __cleanup, __done; \ 220 struct aa_label *__new_; \ 221 \ 222 if ((L)->size > 1) { \ 223 /* TODO: add cache of transitions already done */ \ 224 struct label_it __i; \ 225 int __j, __k, __count; \ 226 DEFINE_VEC(label, __lvec); \ 227 DEFINE_VEC(profile, __pvec); \ 228 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \ 229 __new_ = NULL; \ 230 goto __done; \ 231 } \ 232 __j = 0; \ 233 label_for_each(__i, (L), (P)) { \ 234 __new_ = (FN); \ 235 AA_BUG(!__new_); \ 236 if (IS_ERR(__new_)) \ 237 goto __cleanup; \ 238 __lvec[__j++] = __new_; \ 239 } \ 240 for (__j = __count = 0; __j < (L)->size; __j++) \ 241 __count += __lvec[__j]->size; \ 242 if (!vec_setup(profile, __pvec, __count, (GFP))) { \ 243 for (__j = __k = 0; __j < (L)->size; __j++) { \ 244 label_for_each(__i, __lvec[__j], (P)) \ 245 __pvec[__k++] = aa_get_profile(P); \ 246 } \ 247 __count -= aa_vec_unique(__pvec, __count, 0); \ 248 if (__count > 1) { \ 249 __new_ = aa_vec_find_or_create_label(__pvec,\ 250 __count, (GFP)); \ 251 /* only fails if out of Mem */ \ 252 if (!__new_) \ 253 __new_ = NULL; \ 254 } else \ 255 __new_ = aa_get_label(&__pvec[0]->label); \ 256 vec_cleanup(profile, __pvec, __count); \ 257 } else \ 258 __new_ = NULL; \ 259 __cleanup: \ 260 vec_cleanup(label, __lvec, (L)->size); \ 261 } else { \ 262 (P) = labels_profile(L); \ 263 __new_ = (FN); \ 264 } \ 265 __done: \ 266 if (!__new_) \ 267 AA_DEBUG("label build failed\n"); \ 268 (__new_); \ 269 }) 270 271 272 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \ 273 ({ \ 274 struct aa_label *__new; \ 275 if ((P)->ns != (NS)) \ 276 __new = (OTHER_FN); \ 277 else \ 278 __new = (NS_FN); \ 279 (__new); \ 280 }) 281 282 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \ 283 ({ \ 284 fn_label_build((L), (P), (GFP), \ 285 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \ 286 }) 287 288 #endif /* __AA_LIB_H */ 289