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 #include <linux/lsm_hooks.h> 20 21 #include "match.h" 22 23 /* 24 * DEBUG remains global (no per profile flag) since it is mostly used in sysctl 25 * which is not related to profile accesses. 26 */ 27 28 #define DEBUG_ON (aa_g_debug) 29 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args) 30 #define AA_DEBUG(fmt, args...) \ 31 do { \ 32 if (DEBUG_ON) \ 33 pr_debug_ratelimited("AppArmor: " fmt, ##args); \ 34 } while (0) 35 36 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X) 37 38 #define AA_BUG(X, args...) AA_BUG_FMT((X), "" args) 39 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS 40 #define AA_BUG_FMT(X, fmt, args...) \ 41 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args) 42 #else 43 #define AA_BUG_FMT(X, fmt, args...) 44 #endif 45 46 #define AA_ERROR(fmt, args...) \ 47 pr_err_ratelimited("AppArmor: " fmt, ##args) 48 49 /* Flag indicating whether initialization completed */ 50 extern int apparmor_initialized; 51 52 /* fn's in lib */ 53 const char *skipn_spaces(const char *str, size_t n); 54 char *aa_split_fqname(char *args, char **ns_name); 55 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name, 56 size_t *ns_len); 57 void aa_info_message(const char *str); 58 59 /* Security blob offsets */ 60 extern struct lsm_blob_sizes apparmor_blob_sizes; 61 62 /** 63 * aa_strneq - compare null terminated @str to a non null terminated substring 64 * @str: a null terminated string 65 * @sub: a substring, not necessarily null terminated 66 * @len: length of @sub to compare 67 * 68 * The @str string must be full consumed for this to be considered a match 69 */ 70 static inline bool aa_strneq(const char *str, const char *sub, int len) 71 { 72 return !strncmp(str, sub, len) && !str[len]; 73 } 74 75 /** 76 * aa_dfa_null_transition - step to next state after null character 77 * @dfa: the dfa to match against 78 * @start: the state of the dfa to start matching in 79 * 80 * aa_dfa_null_transition transitions to the next state after a null 81 * character which is not used in standard matching and is only 82 * used to separate pairs. 83 */ 84 static inline unsigned int aa_dfa_null_transition(struct aa_dfa *dfa, 85 unsigned int start) 86 { 87 /* the null transition only needs the string's null terminator byte */ 88 return aa_dfa_next(dfa, start, 0); 89 } 90 91 static inline bool path_mediated_fs(struct dentry *dentry) 92 { 93 return !(dentry->d_sb->s_flags & SB_NOUSER); 94 } 95 96 97 struct counted_str { 98 struct kref count; 99 char name[]; 100 }; 101 102 #define str_to_counted(str) \ 103 ((struct counted_str *)(str - offsetof(struct counted_str, name))) 104 105 #define __counted /* atm just a notation */ 106 107 void aa_str_kref(struct kref *kref); 108 char *aa_str_alloc(int size, gfp_t gfp); 109 110 111 static inline __counted char *aa_get_str(__counted char *str) 112 { 113 if (str) 114 kref_get(&(str_to_counted(str)->count)); 115 116 return str; 117 } 118 119 static inline void aa_put_str(__counted char *str) 120 { 121 if (str) 122 kref_put(&str_to_counted(str)->count, aa_str_kref); 123 } 124 125 126 /* struct aa_policy - common part of both namespaces and profiles 127 * @name: name of the object 128 * @hname - The hierarchical name 129 * @list: list policy object is on 130 * @profiles: head of the profiles list contained in the object 131 */ 132 struct aa_policy { 133 const char *name; 134 __counted char *hname; 135 struct list_head list; 136 struct list_head profiles; 137 }; 138 139 /** 140 * basename - find the last component of an hname 141 * @name: hname to find the base profile name component of (NOT NULL) 142 * 143 * Returns: the tail (base profile name) name component of an hname 144 */ 145 static inline const char *basename(const char *hname) 146 { 147 char *split; 148 149 hname = strim((char *)hname); 150 for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) 151 hname = split + 2; 152 153 return hname; 154 } 155 156 /** 157 * __policy_find - find a policy by @name on a policy list 158 * @head: list to search (NOT NULL) 159 * @name: name to search for (NOT NULL) 160 * 161 * Requires: rcu_read_lock be held 162 * 163 * Returns: unrefcounted policy that match @name or NULL if not found 164 */ 165 static inline struct aa_policy *__policy_find(struct list_head *head, 166 const char *name) 167 { 168 struct aa_policy *policy; 169 170 list_for_each_entry_rcu(policy, head, list) { 171 if (!strcmp(policy->name, name)) 172 return policy; 173 } 174 return NULL; 175 } 176 177 /** 178 * __policy_strn_find - find a policy that's name matches @len chars of @str 179 * @head: list to search (NOT NULL) 180 * @str: string to search for (NOT NULL) 181 * @len: length of match required 182 * 183 * Requires: rcu_read_lock be held 184 * 185 * Returns: unrefcounted policy that match @str or NULL if not found 186 * 187 * if @len == strlen(@strlen) then this is equiv to __policy_find 188 * other wise it allows searching for policy by a partial match of name 189 */ 190 static inline struct aa_policy *__policy_strn_find(struct list_head *head, 191 const char *str, int len) 192 { 193 struct aa_policy *policy; 194 195 list_for_each_entry_rcu(policy, head, list) { 196 if (aa_strneq(policy->name, str, len)) 197 return policy; 198 } 199 200 return NULL; 201 } 202 203 bool aa_policy_init(struct aa_policy *policy, const char *prefix, 204 const char *name, gfp_t gfp); 205 void aa_policy_destroy(struct aa_policy *policy); 206 207 208 /* 209 * fn_label_build - abstract out the build of a label transition 210 * @L: label the transition is being computed for 211 * @P: profile parameter derived from L by this macro, can be passed to FN 212 * @GFP: memory allocation type to use 213 * @FN: fn to call for each profile transition. @P is set to the profile 214 * 215 * Returns: new label on success 216 * ERR_PTR if build @FN fails 217 * NULL if label_build fails due to low memory conditions 218 * 219 * @FN must return a label or ERR_PTR on failure. NULL is not allowed 220 */ 221 #define fn_label_build(L, P, GFP, FN) \ 222 ({ \ 223 __label__ __cleanup, __done; \ 224 struct aa_label *__new_; \ 225 \ 226 if ((L)->size > 1) { \ 227 /* TODO: add cache of transitions already done */ \ 228 struct label_it __i; \ 229 int __j, __k, __count; \ 230 DEFINE_VEC(label, __lvec); \ 231 DEFINE_VEC(profile, __pvec); \ 232 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \ 233 __new_ = NULL; \ 234 goto __done; \ 235 } \ 236 __j = 0; \ 237 label_for_each(__i, (L), (P)) { \ 238 __new_ = (FN); \ 239 AA_BUG(!__new_); \ 240 if (IS_ERR(__new_)) \ 241 goto __cleanup; \ 242 __lvec[__j++] = __new_; \ 243 } \ 244 for (__j = __count = 0; __j < (L)->size; __j++) \ 245 __count += __lvec[__j]->size; \ 246 if (!vec_setup(profile, __pvec, __count, (GFP))) { \ 247 for (__j = __k = 0; __j < (L)->size; __j++) { \ 248 label_for_each(__i, __lvec[__j], (P)) \ 249 __pvec[__k++] = aa_get_profile(P); \ 250 } \ 251 __count -= aa_vec_unique(__pvec, __count, 0); \ 252 if (__count > 1) { \ 253 __new_ = aa_vec_find_or_create_label(__pvec,\ 254 __count, (GFP)); \ 255 /* only fails if out of Mem */ \ 256 if (!__new_) \ 257 __new_ = NULL; \ 258 } else \ 259 __new_ = aa_get_label(&__pvec[0]->label); \ 260 vec_cleanup(profile, __pvec, __count); \ 261 } else \ 262 __new_ = NULL; \ 263 __cleanup: \ 264 vec_cleanup(label, __lvec, (L)->size); \ 265 } else { \ 266 (P) = labels_profile(L); \ 267 __new_ = (FN); \ 268 } \ 269 __done: \ 270 if (!__new_) \ 271 AA_DEBUG("label build failed\n"); \ 272 (__new_); \ 273 }) 274 275 276 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \ 277 ({ \ 278 struct aa_label *__new; \ 279 if ((P)->ns != (NS)) \ 280 __new = (OTHER_FN); \ 281 else \ 282 __new = (NS_FN); \ 283 (__new); \ 284 }) 285 286 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \ 287 ({ \ 288 fn_label_build((L), (P), (GFP), \ 289 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \ 290 }) 291 292 #endif /* __AA_LIB_H */ 293