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 /* 26 * split individual debug cases out in preparation for finer grained 27 * debug controls in the future. 28 */ 29 #define AA_DEBUG_LABEL DEBUG_ON 30 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args) 31 #define AA_DEBUG(fmt, args...) \ 32 do { \ 33 if (DEBUG_ON) \ 34 pr_debug_ratelimited("AppArmor: " fmt, ##args); \ 35 } while (0) 36 37 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X) 38 39 #define AA_BUG(X, args...) \ 40 do { \ 41 _Pragma("GCC diagnostic ignored \"-Wformat-zero-length\""); \ 42 AA_BUG_FMT((X), "" args); \ 43 _Pragma("GCC diagnostic warning \"-Wformat-zero-length\""); \ 44 } while (0) 45 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS 46 #define AA_BUG_FMT(X, fmt, args...) \ 47 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args) 48 #else 49 #define AA_BUG_FMT(X, fmt, args...) no_printk(fmt, ##args) 50 #endif 51 52 #define AA_ERROR(fmt, args...) \ 53 pr_err_ratelimited("AppArmor: " fmt, ##args) 54 55 /* Flag indicating whether initialization completed */ 56 extern int apparmor_initialized; 57 58 /* fn's in lib */ 59 const char *skipn_spaces(const char *str, size_t n); 60 char *aa_split_fqname(char *args, char **ns_name); 61 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name, 62 size_t *ns_len); 63 void aa_info_message(const char *str); 64 65 /* Security blob offsets */ 66 extern struct lsm_blob_sizes apparmor_blob_sizes; 67 68 /** 69 * aa_strneq - compare null terminated @str to a non null terminated substring 70 * @str: a null terminated string 71 * @sub: a substring, not necessarily null terminated 72 * @len: length of @sub to compare 73 * 74 * The @str string must be full consumed for this to be considered a match 75 */ 76 static inline bool aa_strneq(const char *str, const char *sub, int len) 77 { 78 return !strncmp(str, sub, len) && !str[len]; 79 } 80 81 /** 82 * aa_dfa_null_transition - step to next state after null character 83 * @dfa: the dfa to match against 84 * @start: the state of the dfa to start matching in 85 * 86 * aa_dfa_null_transition transitions to the next state after a null 87 * character which is not used in standard matching and is only 88 * used to separate pairs. 89 */ 90 static inline aa_state_t aa_dfa_null_transition(struct aa_dfa *dfa, 91 aa_state_t start) 92 { 93 /* the null transition only needs the string's null terminator byte */ 94 return aa_dfa_next(dfa, start, 0); 95 } 96 97 static inline bool path_mediated_fs(struct dentry *dentry) 98 { 99 return !(dentry->d_sb->s_flags & SB_NOUSER); 100 } 101 102 struct aa_str_table { 103 int size; 104 char **table; 105 }; 106 107 void aa_free_str_table(struct aa_str_table *table); 108 109 struct counted_str { 110 struct kref count; 111 char name[]; 112 }; 113 114 #define str_to_counted(str) \ 115 ((struct counted_str *)(str - offsetof(struct counted_str, name))) 116 117 #define __counted /* atm just a notation */ 118 119 void aa_str_kref(struct kref *kref); 120 char *aa_str_alloc(int size, gfp_t gfp); 121 122 123 static inline __counted char *aa_get_str(__counted char *str) 124 { 125 if (str) 126 kref_get(&(str_to_counted(str)->count)); 127 128 return str; 129 } 130 131 static inline void aa_put_str(__counted char *str) 132 { 133 if (str) 134 kref_put(&str_to_counted(str)->count, aa_str_kref); 135 } 136 137 138 /* struct aa_policy - common part of both namespaces and profiles 139 * @name: name of the object 140 * @hname - The hierarchical name 141 * @list: list policy object is on 142 * @profiles: head of the profiles list contained in the object 143 */ 144 struct aa_policy { 145 const char *name; 146 __counted char *hname; 147 struct list_head list; 148 struct list_head profiles; 149 }; 150 151 /** 152 * basename - find the last component of an hname 153 * @name: hname to find the base profile name component of (NOT NULL) 154 * 155 * Returns: the tail (base profile name) name component of an hname 156 */ 157 static inline const char *basename(const char *hname) 158 { 159 char *split; 160 161 hname = strim((char *)hname); 162 for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) 163 hname = split + 2; 164 165 return hname; 166 } 167 168 /** 169 * __policy_find - find a policy by @name on a policy list 170 * @head: list to search (NOT NULL) 171 * @name: name to search for (NOT NULL) 172 * 173 * Requires: rcu_read_lock be held 174 * 175 * Returns: unrefcounted policy that match @name or NULL if not found 176 */ 177 static inline struct aa_policy *__policy_find(struct list_head *head, 178 const char *name) 179 { 180 struct aa_policy *policy; 181 182 list_for_each_entry_rcu(policy, head, list) { 183 if (!strcmp(policy->name, name)) 184 return policy; 185 } 186 return NULL; 187 } 188 189 /** 190 * __policy_strn_find - find a policy that's name matches @len chars of @str 191 * @head: list to search (NOT NULL) 192 * @str: string to search for (NOT NULL) 193 * @len: length of match required 194 * 195 * Requires: rcu_read_lock be held 196 * 197 * Returns: unrefcounted policy that match @str or NULL if not found 198 * 199 * if @len == strlen(@strlen) then this is equiv to __policy_find 200 * other wise it allows searching for policy by a partial match of name 201 */ 202 static inline struct aa_policy *__policy_strn_find(struct list_head *head, 203 const char *str, int len) 204 { 205 struct aa_policy *policy; 206 207 list_for_each_entry_rcu(policy, head, list) { 208 if (aa_strneq(policy->name, str, len)) 209 return policy; 210 } 211 212 return NULL; 213 } 214 215 bool aa_policy_init(struct aa_policy *policy, const char *prefix, 216 const char *name, gfp_t gfp); 217 void aa_policy_destroy(struct aa_policy *policy); 218 219 220 /* 221 * fn_label_build - abstract out the build of a label transition 222 * @L: label the transition is being computed for 223 * @P: profile parameter derived from L by this macro, can be passed to FN 224 * @GFP: memory allocation type to use 225 * @FN: fn to call for each profile transition. @P is set to the profile 226 * 227 * Returns: new label on success 228 * ERR_PTR if build @FN fails 229 * NULL if label_build fails due to low memory conditions 230 * 231 * @FN must return a label or ERR_PTR on failure. NULL is not allowed 232 */ 233 #define fn_label_build(L, P, GFP, FN) \ 234 ({ \ 235 __label__ __cleanup, __done; \ 236 struct aa_label *__new_; \ 237 \ 238 if ((L)->size > 1) { \ 239 /* TODO: add cache of transitions already done */ \ 240 struct label_it __i; \ 241 int __j, __k, __count; \ 242 DEFINE_VEC(label, __lvec); \ 243 DEFINE_VEC(profile, __pvec); \ 244 if (vec_setup(label, __lvec, (L)->size, (GFP))) { \ 245 __new_ = NULL; \ 246 goto __done; \ 247 } \ 248 __j = 0; \ 249 label_for_each(__i, (L), (P)) { \ 250 __new_ = (FN); \ 251 AA_BUG(!__new_); \ 252 if (IS_ERR(__new_)) \ 253 goto __cleanup; \ 254 __lvec[__j++] = __new_; \ 255 } \ 256 for (__j = __count = 0; __j < (L)->size; __j++) \ 257 __count += __lvec[__j]->size; \ 258 if (!vec_setup(profile, __pvec, __count, (GFP))) { \ 259 for (__j = __k = 0; __j < (L)->size; __j++) { \ 260 label_for_each(__i, __lvec[__j], (P)) \ 261 __pvec[__k++] = aa_get_profile(P); \ 262 } \ 263 __count -= aa_vec_unique(__pvec, __count, 0); \ 264 if (__count > 1) { \ 265 __new_ = aa_vec_find_or_create_label(__pvec,\ 266 __count, (GFP)); \ 267 /* only fails if out of Mem */ \ 268 if (!__new_) \ 269 __new_ = NULL; \ 270 } else \ 271 __new_ = aa_get_label(&__pvec[0]->label); \ 272 vec_cleanup(profile, __pvec, __count); \ 273 } else \ 274 __new_ = NULL; \ 275 __cleanup: \ 276 vec_cleanup(label, __lvec, (L)->size); \ 277 } else { \ 278 (P) = labels_profile(L); \ 279 __new_ = (FN); \ 280 } \ 281 __done: \ 282 if (!__new_) \ 283 AA_DEBUG("label build failed\n"); \ 284 (__new_); \ 285 }) 286 287 288 #define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \ 289 ({ \ 290 struct aa_label *__new; \ 291 if ((P)->ns != (NS)) \ 292 __new = (OTHER_FN); \ 293 else \ 294 __new = (NS_FN); \ 295 (__new); \ 296 }) 297 298 #define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \ 299 ({ \ 300 fn_label_build((L), (P), (GFP), \ 301 __fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \ 302 }) 303 304 #endif /* __AA_LIB_H */ 305