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 extern struct aa_dfa *stacksplitdfa; 20 21 /* 22 * DEBUG remains global (no per profile flag) since it is mostly used in sysctl 23 * which is not related to profile accesses. 24 */ 25 26 #define DEBUG_ON (aa_g_debug) 27 /* 28 * split individual debug cases out in preparation for finer grained 29 * debug controls in the future. 30 */ 31 #define AA_DEBUG_LABEL DEBUG_ON 32 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args) 33 #define AA_DEBUG(fmt, args...) \ 34 do { \ 35 if (DEBUG_ON) \ 36 pr_debug_ratelimited("AppArmor: " fmt, ##args); \ 37 } while (0) 38 39 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X) 40 41 #define AA_BUG(X, args...) \ 42 do { \ 43 _Pragma("GCC diagnostic ignored \"-Wformat-zero-length\""); \ 44 AA_BUG_FMT((X), "" args); \ 45 _Pragma("GCC diagnostic warning \"-Wformat-zero-length\""); \ 46 } while (0) 47 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS 48 #define AA_BUG_FMT(X, fmt, args...) \ 49 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args) 50 #else 51 #define AA_BUG_FMT(X, fmt, args...) no_printk(fmt, ##args) 52 #endif 53 54 #define AA_ERROR(fmt, args...) \ 55 pr_err_ratelimited("AppArmor: " fmt, ##args) 56 57 /* Flag indicating whether initialization completed */ 58 extern int apparmor_initialized; 59 60 /* fn's in lib */ 61 const char *skipn_spaces(const char *str, size_t n); 62 char *aa_split_fqname(char *args, char **ns_name); 63 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name, 64 size_t *ns_len); 65 void aa_info_message(const char *str); 66 67 /* Security blob offsets */ 68 extern struct lsm_blob_sizes apparmor_blob_sizes; 69 70 /** 71 * aa_strneq - compare null terminated @str to a non null terminated substring 72 * @str: a null terminated string 73 * @sub: a substring, not necessarily null terminated 74 * @len: length of @sub to compare 75 * 76 * The @str string must be full consumed for this to be considered a match 77 */ 78 static inline bool aa_strneq(const char *str, const char *sub, int len) 79 { 80 return !strncmp(str, sub, len) && !str[len]; 81 } 82 83 /** 84 * aa_dfa_null_transition - step to next state after null character 85 * @dfa: the dfa to match against 86 * @start: the state of the dfa to start matching in 87 * 88 * aa_dfa_null_transition transitions to the next state after a null 89 * character which is not used in standard matching and is only 90 * used to separate pairs. 91 */ 92 static inline aa_state_t aa_dfa_null_transition(struct aa_dfa *dfa, 93 aa_state_t start) 94 { 95 /* the null transition only needs the string's null terminator byte */ 96 return aa_dfa_next(dfa, start, 0); 97 } 98 99 static inline bool path_mediated_fs(struct dentry *dentry) 100 { 101 return !(dentry->d_sb->s_flags & SB_NOUSER); 102 } 103 104 struct aa_str_table { 105 int size; 106 char **table; 107 }; 108 109 void aa_free_str_table(struct aa_str_table *table); 110 111 struct counted_str { 112 struct kref count; 113 char name[]; 114 }; 115 116 #define str_to_counted(str) \ 117 ((struct counted_str *)(str - offsetof(struct counted_str, name))) 118 119 #define __counted /* atm just a notation */ 120 121 void aa_str_kref(struct kref *kref); 122 char *aa_str_alloc(int size, gfp_t gfp); 123 124 125 static inline __counted char *aa_get_str(__counted char *str) 126 { 127 if (str) 128 kref_get(&(str_to_counted(str)->count)); 129 130 return str; 131 } 132 133 static inline void aa_put_str(__counted char *str) 134 { 135 if (str) 136 kref_put(&str_to_counted(str)->count, aa_str_kref); 137 } 138 139 140 /* struct aa_policy - common part of both namespaces and profiles 141 * @name: name of the object 142 * @hname - The hierarchical name 143 * @list: list policy object is on 144 * @profiles: head of the profiles list contained in the object 145 */ 146 struct aa_policy { 147 const char *name; 148 __counted char *hname; 149 struct list_head list; 150 struct list_head profiles; 151 }; 152 153 /** 154 * basename - find the last component of an hname 155 * @name: hname to find the base profile name component of (NOT NULL) 156 * 157 * Returns: the tail (base profile name) name component of an hname 158 */ 159 static inline const char *basename(const char *hname) 160 { 161 char *split; 162 163 hname = strim((char *)hname); 164 for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) 165 hname = split + 2; 166 167 return hname; 168 } 169 170 /** 171 * __policy_find - find a policy by @name on a policy list 172 * @head: list to search (NOT NULL) 173 * @name: name to search for (NOT NULL) 174 * 175 * Requires: rcu_read_lock be held 176 * 177 * Returns: unrefcounted policy that match @name or NULL if not found 178 */ 179 static inline struct aa_policy *__policy_find(struct list_head *head, 180 const char *name) 181 { 182 struct aa_policy *policy; 183 184 list_for_each_entry_rcu(policy, head, list) { 185 if (!strcmp(policy->name, name)) 186 return policy; 187 } 188 return NULL; 189 } 190 191 /** 192 * __policy_strn_find - find a policy that's name matches @len chars of @str 193 * @head: list to search (NOT NULL) 194 * @str: string to search for (NOT NULL) 195 * @len: length of match required 196 * 197 * Requires: rcu_read_lock be held 198 * 199 * Returns: unrefcounted policy that match @str or NULL if not found 200 * 201 * if @len == strlen(@strlen) then this is equiv to __policy_find 202 * other wise it allows searching for policy by a partial match of name 203 */ 204 static inline struct aa_policy *__policy_strn_find(struct list_head *head, 205 const char *str, int len) 206 { 207 struct aa_policy *policy; 208 209 list_for_each_entry_rcu(policy, head, list) { 210 if (aa_strneq(policy->name, str, len)) 211 return policy; 212 } 213 214 return NULL; 215 } 216 217 bool aa_policy_init(struct aa_policy *policy, const char *prefix, 218 const char *name, gfp_t gfp); 219 void aa_policy_destroy(struct aa_policy *policy); 220 221 222 /* 223 * fn_label_build - abstract out the build of a label transition 224 * @L: label the transition is being computed for 225 * @P: profile parameter derived from L by this macro, can be passed to FN 226 * @GFP: memory allocation type to use 227 * @FN: fn to call for each profile transition. @P is set to the profile 228 * 229 * Returns: new label on success 230 * ERR_PTR if build @FN fails 231 * NULL if label_build fails due to low memory conditions 232 * 233 * @FN must return a label or ERR_PTR on failure. NULL is not allowed 234 */ 235 #define fn_label_build(L, P, GFP, FN) \ 236 ({ \ 237 __label__ __do_cleanup, __done; \ 238 struct aa_label *__new_; \ 239 \ 240 if ((L)->size > 1) { \ 241 /* TODO: add cache of transitions already done */ \ 242 struct label_it __i; \ 243 int __j, __k, __count; \ 244 DEFINE_VEC(label, __lvec); \ 245 DEFINE_VEC(profile, __pvec); \ 246 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \ 247 __new_ = NULL; \ 248 goto __done; \ 249 } \ 250 __j = 0; \ 251 label_for_each(__i, (L), (P)) { \ 252 __new_ = (FN); \ 253 AA_BUG(!__new_); \ 254 if (IS_ERR(__new_)) \ 255 goto __do_cleanup; \ 256 __lvec[__j++] = __new_; \ 257 } \ 258 for (__j = __count = 0; __j < (L)->size; __j++) \ 259 __count += __lvec[__j]->size; \ 260 if (!vec_setup(profile, __pvec, __count, (GFP))) { \ 261 for (__j = __k = 0; __j < (L)->size; __j++) { \ 262 label_for_each(__i, __lvec[__j], (P)) \ 263 __pvec[__k++] = aa_get_profile(P); \ 264 } \ 265 __count -= aa_vec_unique(__pvec, __count, 0); \ 266 if (__count > 1) { \ 267 __new_ = aa_vec_find_or_create_label(__pvec,\ 268 __count, (GFP)); \ 269 /* only fails if out of Mem */ \ 270 if (!__new_) \ 271 __new_ = NULL; \ 272 } else \ 273 __new_ = aa_get_label(&__pvec[0]->label); \ 274 vec_cleanup(profile, __pvec, __count); \ 275 } else \ 276 __new_ = NULL; \ 277 __do_cleanup: \ 278 vec_cleanup(label, __lvec, (L)->size); \ 279 } else { \ 280 (P) = labels_profile(L); \ 281 __new_ = (FN); \ 282 } \ 283 __done: \ 284 if (!__new_) \ 285 AA_DEBUG("label build failed\n"); \ 286 (__new_); \ 287 }) 288 289 290 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \ 291 ({ \ 292 struct aa_label *__new; \ 293 if ((P)->ns != (NS)) \ 294 __new = (OTHER_FN); \ 295 else \ 296 __new = (NS_FN); \ 297 (__new); \ 298 }) 299 300 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \ 301 ({ \ 302 fn_label_build((L), (P), (GFP), \ 303 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \ 304 }) 305 306 #endif /* __AA_LIB_H */ 307