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 19 /* 20 * DEBUG remains global (no per profile flag) since it is mostly used in sysctl 21 * which is not related to profile accesses. 22 */ 23 24 #define DEBUG_ON (aa_g_debug) 25 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args) 26 #define AA_DEBUG(fmt, args...) \ 27 do { \ 28 if (DEBUG_ON) \ 29 pr_debug_ratelimited("AppArmor: " fmt, ##args); \ 30 } while (0) 31 32 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X) 33 34 #define AA_BUG(X, args...) \ 35 do { \ 36 _Pragma("GCC diagnostic ignored \"-Wformat-zero-length\""); \ 37 AA_BUG_FMT((X), "" args); \ 38 _Pragma("GCC diagnostic warning \"-Wformat-zero-length\""); \ 39 } while (0) 40 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS 41 #define AA_BUG_FMT(X, fmt, args...) \ 42 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args) 43 #else 44 #define AA_BUG_FMT(X, fmt, args...) no_printk(fmt, ##args) 45 #endif 46 47 #define AA_ERROR(fmt, args...) \ 48 pr_err_ratelimited("AppArmor: " fmt, ##args) 49 50 /* Flag indicating whether initialization completed */ 51 extern int apparmor_initialized; 52 53 /* fn's in lib */ 54 const char *skipn_spaces(const char *str, size_t n); 55 char *aa_split_fqname(char *args, char **ns_name); 56 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name, 57 size_t *ns_len); 58 void aa_info_message(const char *str); 59 60 /* Security blob offsets */ 61 extern struct lsm_blob_sizes apparmor_blob_sizes; 62 63 /** 64 * aa_strneq - compare null terminated @str to a non null terminated substring 65 * @str: a null terminated string 66 * @sub: a substring, not necessarily null terminated 67 * @len: length of @sub to compare 68 * 69 * The @str string must be full consumed for this to be considered a match 70 */ 71 static inline bool aa_strneq(const char *str, const char *sub, int len) 72 { 73 return !strncmp(str, sub, len) && !str[len]; 74 } 75 76 /** 77 * aa_dfa_null_transition - step to next state after null character 78 * @dfa: the dfa to match against 79 * @start: the state of the dfa to start matching in 80 * 81 * aa_dfa_null_transition transitions to the next state after a null 82 * character which is not used in standard matching and is only 83 * used to separate pairs. 84 */ 85 static inline unsigned int aa_dfa_null_transition(struct aa_dfa *dfa, 86 unsigned int start) 87 { 88 /* the null transition only needs the string's null terminator byte */ 89 return aa_dfa_next(dfa, start, 0); 90 } 91 92 static inline bool path_mediated_fs(struct dentry *dentry) 93 { 94 return !(dentry->d_sb->s_flags & SB_NOUSER); 95 } 96 97 98 struct counted_str { 99 struct kref count; 100 char name[]; 101 }; 102 103 #define str_to_counted(str) \ 104 ((struct counted_str *)(str - offsetof(struct counted_str, name))) 105 106 #define __counted /* atm just a notation */ 107 108 void aa_str_kref(struct kref *kref); 109 char *aa_str_alloc(int size, gfp_t gfp); 110 111 112 static inline __counted char *aa_get_str(__counted char *str) 113 { 114 if (str) 115 kref_get(&(str_to_counted(str)->count)); 116 117 return str; 118 } 119 120 static inline void aa_put_str(__counted char *str) 121 { 122 if (str) 123 kref_put(&str_to_counted(str)->count, aa_str_kref); 124 } 125 126 127 /* struct aa_policy - common part of both namespaces and profiles 128 * @name: name of the object 129 * @hname - The hierarchical name 130 * @list: list policy object is on 131 * @profiles: head of the profiles list contained in the object 132 */ 133 struct aa_policy { 134 const char *name; 135 __counted char *hname; 136 struct list_head list; 137 struct list_head profiles; 138 }; 139 140 /** 141 * basename - find the last component of an hname 142 * @name: hname to find the base profile name component of (NOT NULL) 143 * 144 * Returns: the tail (base profile name) name component of an hname 145 */ 146 static inline const char *basename(const char *hname) 147 { 148 char *split; 149 150 hname = strim((char *)hname); 151 for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) 152 hname = split + 2; 153 154 return hname; 155 } 156 157 /** 158 * __policy_find - find a policy by @name on a policy list 159 * @head: list to search (NOT NULL) 160 * @name: name to search for (NOT NULL) 161 * 162 * Requires: rcu_read_lock be held 163 * 164 * Returns: unrefcounted policy that match @name or NULL if not found 165 */ 166 static inline struct aa_policy *__policy_find(struct list_head *head, 167 const char *name) 168 { 169 struct aa_policy *policy; 170 171 list_for_each_entry_rcu(policy, head, list) { 172 if (!strcmp(policy->name, name)) 173 return policy; 174 } 175 return NULL; 176 } 177 178 /** 179 * __policy_strn_find - find a policy that's name matches @len chars of @str 180 * @head: list to search (NOT NULL) 181 * @str: string to search for (NOT NULL) 182 * @len: length of match required 183 * 184 * Requires: rcu_read_lock be held 185 * 186 * Returns: unrefcounted policy that match @str or NULL if not found 187 * 188 * if @len == strlen(@strlen) then this is equiv to __policy_find 189 * other wise it allows searching for policy by a partial match of name 190 */ 191 static inline struct aa_policy *__policy_strn_find(struct list_head *head, 192 const char *str, int len) 193 { 194 struct aa_policy *policy; 195 196 list_for_each_entry_rcu(policy, head, list) { 197 if (aa_strneq(policy->name, str, len)) 198 return policy; 199 } 200 201 return NULL; 202 } 203 204 bool aa_policy_init(struct aa_policy *policy, const char *prefix, 205 const char *name, gfp_t gfp); 206 void aa_policy_destroy(struct aa_policy *policy); 207 208 209 /* 210 * fn_label_build - abstract out the build of a label transition 211 * @L: label the transition is being computed for 212 * @P: profile parameter derived from L by this macro, can be passed to FN 213 * @GFP: memory allocation type to use 214 * @FN: fn to call for each profile transition. @P is set to the profile 215 * 216 * Returns: new label on success 217 * ERR_PTR if build @FN fails 218 * NULL if label_build fails due to low memory conditions 219 * 220 * @FN must return a label or ERR_PTR on failure. NULL is not allowed 221 */ 222 #define fn_label_build(L, P, GFP, FN) \ 223 ({ \ 224 __label__ __cleanup, __done; \ 225 struct aa_label *__new_; \ 226 \ 227 if ((L)->size > 1) { \ 228 /* TODO: add cache of transitions already done */ \ 229 struct label_it __i; \ 230 int __j, __k, __count; \ 231 DEFINE_VEC(label, __lvec); \ 232 DEFINE_VEC(profile, __pvec); \ 233 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \ 234 __new_ = NULL; \ 235 goto __done; \ 236 } \ 237 __j = 0; \ 238 label_for_each(__i, (L), (P)) { \ 239 __new_ = (FN); \ 240 AA_BUG(!__new_); \ 241 if (IS_ERR(__new_)) \ 242 goto __cleanup; \ 243 __lvec[__j++] = __new_; \ 244 } \ 245 for (__j = __count = 0; __j < (L)->size; __j++) \ 246 __count += __lvec[__j]->size; \ 247 if (!vec_setup(profile, __pvec, __count, (GFP))) { \ 248 for (__j = __k = 0; __j < (L)->size; __j++) { \ 249 label_for_each(__i, __lvec[__j], (P)) \ 250 __pvec[__k++] = aa_get_profile(P); \ 251 } \ 252 __count -= aa_vec_unique(__pvec, __count, 0); \ 253 if (__count > 1) { \ 254 __new_ = aa_vec_find_or_create_label(__pvec,\ 255 __count, (GFP)); \ 256 /* only fails if out of Mem */ \ 257 if (!__new_) \ 258 __new_ = NULL; \ 259 } else \ 260 __new_ = aa_get_label(&__pvec[0]->label); \ 261 vec_cleanup(profile, __pvec, __count); \ 262 } else \ 263 __new_ = NULL; \ 264 __cleanup: \ 265 vec_cleanup(label, __lvec, (L)->size); \ 266 } else { \ 267 (P) = labels_profile(L); \ 268 __new_ = (FN); \ 269 } \ 270 __done: \ 271 if (!__new_) \ 272 AA_DEBUG("label build failed\n"); \ 273 (__new_); \ 274 }) 275 276 277 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \ 278 ({ \ 279 struct aa_label *__new; \ 280 if ((P)->ns != (NS)) \ 281 __new = (OTHER_FN); \ 282 else \ 283 __new = (NS_FN); \ 284 (__new); \ 285 }) 286 287 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \ 288 ({ \ 289 fn_label_build((L), (P), (GFP), \ 290 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \ 291 }) 292 293 #endif /* __AA_LIB_H */ 294