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 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name, 63 size_t *ns_len); 64 void aa_info_message(const char *str); 65 66 /* Security blob offsets */ 67 extern struct lsm_blob_sizes apparmor_blob_sizes; 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 aa_state_t aa_dfa_null_transition(struct aa_dfa *dfa, 92 aa_state_t 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 & SB_NOUSER); 101 } 102 103 struct aa_str_table { 104 int size; 105 char **table; 106 }; 107 108 void aa_free_str_table(struct aa_str_table *table); 109 110 struct counted_str { 111 struct kref count; 112 char name[]; 113 }; 114 115 #define str_to_counted(str) \ 116 ((struct counted_str *)(str - offsetof(struct counted_str, name))) 117 118 #define __counted /* atm just a notation */ 119 120 void aa_str_kref(struct kref *kref); 121 char *aa_str_alloc(int size, gfp_t gfp); 122 123 124 static inline __counted char *aa_get_str(__counted char *str) 125 { 126 if (str) 127 kref_get(&(str_to_counted(str)->count)); 128 129 return str; 130 } 131 132 static inline void aa_put_str(__counted char *str) 133 { 134 if (str) 135 kref_put(&str_to_counted(str)->count, aa_str_kref); 136 } 137 138 139 /* struct aa_policy - common part of both namespaces and profiles 140 * @name: name of the object 141 * @hname - The hierarchical name 142 * @list: list policy object is on 143 * @profiles: head of the profiles list contained in the object 144 */ 145 struct aa_policy { 146 const char *name; 147 __counted char *hname; 148 struct list_head list; 149 struct list_head profiles; 150 }; 151 152 /** 153 * basename - find the last component of an hname 154 * @name: hname to find the base profile name component of (NOT NULL) 155 * 156 * Returns: the tail (base profile name) name component of an hname 157 */ 158 static inline const char *basename(const char *hname) 159 { 160 char *split; 161 162 hname = strim((char *)hname); 163 for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) 164 hname = split + 2; 165 166 return hname; 167 } 168 169 /** 170 * __policy_find - find a policy by @name on a policy list 171 * @head: list to search (NOT NULL) 172 * @name: name to search for (NOT NULL) 173 * 174 * Requires: rcu_read_lock be held 175 * 176 * Returns: unrefcounted policy that match @name or NULL if not found 177 */ 178 static inline struct aa_policy *__policy_find(struct list_head *head, 179 const char *name) 180 { 181 struct aa_policy *policy; 182 183 list_for_each_entry_rcu(policy, head, list) { 184 if (!strcmp(policy->name, name)) 185 return policy; 186 } 187 return NULL; 188 } 189 190 /** 191 * __policy_strn_find - find a policy that's name matches @len chars of @str 192 * @head: list to search (NOT NULL) 193 * @str: string to search for (NOT NULL) 194 * @len: length of match required 195 * 196 * Requires: rcu_read_lock be held 197 * 198 * Returns: unrefcounted policy that match @str or NULL if not found 199 * 200 * if @len == strlen(@strlen) then this is equiv to __policy_find 201 * other wise it allows searching for policy by a partial match of name 202 */ 203 static inline struct aa_policy *__policy_strn_find(struct list_head *head, 204 const char *str, int len) 205 { 206 struct aa_policy *policy; 207 208 list_for_each_entry_rcu(policy, head, list) { 209 if (aa_strneq(policy->name, str, len)) 210 return policy; 211 } 212 213 return NULL; 214 } 215 216 bool aa_policy_init(struct aa_policy *policy, const char *prefix, 217 const char *name, gfp_t gfp); 218 void aa_policy_destroy(struct aa_policy *policy); 219 220 221 /* 222 * fn_label_build - abstract out the build of a label transition 223 * @L: label the transition is being computed for 224 * @P: profile parameter derived from L by this macro, can be passed to FN 225 * @GFP: memory allocation type to use 226 * @FN: fn to call for each profile transition. @P is set to the profile 227 * 228 * Returns: new label on success 229 * ERR_PTR if build @FN fails 230 * NULL if label_build fails due to low memory conditions 231 * 232 * @FN must return a label or ERR_PTR on failure. NULL is not allowed 233 */ 234 #define fn_label_build(L, P, GFP, FN) \ 235 ({ \ 236 __label__ __do_cleanup, __done; \ 237 struct aa_label *__new_; \ 238 \ 239 if ((L)->size > 1) { \ 240 /* TODO: add cache of transitions already done */ \ 241 struct label_it __i; \ 242 int __j, __k, __count; \ 243 DEFINE_VEC(label, __lvec); \ 244 DEFINE_VEC(profile, __pvec); \ 245 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \ 246 __new_ = NULL; \ 247 goto __done; \ 248 } \ 249 __j = 0; \ 250 label_for_each(__i, (L), (P)) { \ 251 __new_ = (FN); \ 252 AA_BUG(!__new_); \ 253 if (IS_ERR(__new_)) \ 254 goto __do_cleanup; \ 255 __lvec[__j++] = __new_; \ 256 } \ 257 for (__j = __count = 0; __j < (L)->size; __j++) \ 258 __count += __lvec[__j]->size; \ 259 if (!vec_setup(profile, __pvec, __count, (GFP))) { \ 260 for (__j = __k = 0; __j < (L)->size; __j++) { \ 261 label_for_each(__i, __lvec[__j], (P)) \ 262 __pvec[__k++] = aa_get_profile(P); \ 263 } \ 264 __count -= aa_vec_unique(__pvec, __count, 0); \ 265 if (__count > 1) { \ 266 __new_ = aa_vec_find_or_create_label(__pvec,\ 267 __count, (GFP)); \ 268 /* only fails if out of Mem */ \ 269 if (!__new_) \ 270 __new_ = NULL; \ 271 } else \ 272 __new_ = aa_get_label(&__pvec[0]->label); \ 273 vec_cleanup(profile, __pvec, __count); \ 274 } else \ 275 __new_ = NULL; \ 276 __do_cleanup: \ 277 vec_cleanup(label, __lvec, (L)->size); \ 278 } else { \ 279 (P) = labels_profile(L); \ 280 __new_ = (FN); \ 281 } \ 282 __done: \ 283 if (!__new_) \ 284 AA_DEBUG("label build failed\n"); \ 285 (__new_); \ 286 }) 287 288 289 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \ 290 ({ \ 291 struct aa_label *__new; \ 292 if ((P)->ns != (NS)) \ 293 __new = (OTHER_FN); \ 294 else \ 295 __new = (NS_FN); \ 296 (__new); \ 297 }) 298 299 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \ 300 ({ \ 301 fn_label_build((L), (P), (GFP), \ 302 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \ 303 }) 304 305 #endif /* __AA_LIB_H */ 306