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 20 #include "match.h" 21 22 /* Provide our own test for whether a write lock is held for asserts 23 * this is because on none SMP systems write_can_lock will always 24 * resolve to true, which is what you want for code making decisions 25 * based on it, but wrong for asserts checking that the lock is held 26 */ 27 #ifdef CONFIG_SMP 28 #define write_is_locked(X) !write_can_lock(X) 29 #else 30 #define write_is_locked(X) (1) 31 #endif /* CONFIG_SMP */ 32 33 /* 34 * DEBUG remains global (no per profile flag) since it is mostly used in sysctl 35 * which is not related to profile accesses. 36 */ 37 38 #define DEBUG_ON (aa_g_debug) 39 #define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args) 40 #define AA_DEBUG(fmt, args...) \ 41 do { \ 42 if (DEBUG_ON) \ 43 pr_debug_ratelimited("AppArmor: " fmt, ##args); \ 44 } while (0) 45 46 #define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X) 47 48 #define AA_BUG(X, args...) AA_BUG_FMT((X), "" args) 49 #ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS 50 #define AA_BUG_FMT(X, fmt, args...) \ 51 WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args) 52 #else 53 #define AA_BUG_FMT(X, fmt, args...) 54 #endif 55 56 #define AA_ERROR(fmt, args...) \ 57 pr_err_ratelimited("AppArmor: " fmt, ##args) 58 59 /* Flag indicating whether initialization completed */ 60 extern int apparmor_initialized; 61 62 /* fn's in lib */ 63 const char *skipn_spaces(const char *str, size_t n); 64 char *aa_split_fqname(char *args, char **ns_name); 65 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name, 66 size_t *ns_len); 67 void aa_info_message(const char *str); 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 unsigned int aa_dfa_null_transition(struct aa_dfa *dfa, 92 unsigned int 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 & MS_NOUSER); 101 } 102 103 /* struct aa_policy - common part of both namespaces and profiles 104 * @name: name of the object 105 * @hname - The hierarchical name 106 * @list: list policy object is on 107 * @profiles: head of the profiles list contained in the object 108 */ 109 struct aa_policy { 110 const char *name; 111 const char *hname; 112 struct list_head list; 113 struct list_head profiles; 114 }; 115 116 /** 117 * basename - find the last component of an hname 118 * @name: hname to find the base profile name component of (NOT NULL) 119 * 120 * Returns: the tail (base profile name) name component of an hname 121 */ 122 static inline const char *basename(const char *hname) 123 { 124 char *split; 125 126 hname = strim((char *)hname); 127 for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) 128 hname = split + 2; 129 130 return hname; 131 } 132 133 /** 134 * __policy_find - find a policy by @name on a policy list 135 * @head: list to search (NOT NULL) 136 * @name: name to search for (NOT NULL) 137 * 138 * Requires: rcu_read_lock be held 139 * 140 * Returns: unrefcounted policy that match @name or NULL if not found 141 */ 142 static inline struct aa_policy *__policy_find(struct list_head *head, 143 const char *name) 144 { 145 struct aa_policy *policy; 146 147 list_for_each_entry_rcu(policy, head, list) { 148 if (!strcmp(policy->name, name)) 149 return policy; 150 } 151 return NULL; 152 } 153 154 /** 155 * __policy_strn_find - find a policy that's name matches @len chars of @str 156 * @head: list to search (NOT NULL) 157 * @str: string to search for (NOT NULL) 158 * @len: length of match required 159 * 160 * Requires: rcu_read_lock be held 161 * 162 * Returns: unrefcounted policy that match @str or NULL if not found 163 * 164 * if @len == strlen(@strlen) then this is equiv to __policy_find 165 * other wise it allows searching for policy by a partial match of name 166 */ 167 static inline struct aa_policy *__policy_strn_find(struct list_head *head, 168 const char *str, int len) 169 { 170 struct aa_policy *policy; 171 172 list_for_each_entry_rcu(policy, head, list) { 173 if (aa_strneq(policy->name, str, len)) 174 return policy; 175 } 176 177 return NULL; 178 } 179 180 bool aa_policy_init(struct aa_policy *policy, const char *prefix, 181 const char *name, gfp_t gfp); 182 void aa_policy_destroy(struct aa_policy *policy); 183 184 #endif /* AA_LIB_H */ 185