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 char *aa_split_fqname(char *args, char **ns_name); 64 const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name, 65 size_t *ns_len); 66 void aa_info_message(const char *str); 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 unsigned int aa_dfa_null_transition(struct aa_dfa *dfa, 91 unsigned int 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 & MS_NOUSER); 100 } 101 102 /* struct aa_policy - common part of both namespaces and profiles 103 * @name: name of the object 104 * @hname - The hierarchical name 105 * @list: list policy object is on 106 * @profiles: head of the profiles list contained in the object 107 */ 108 struct aa_policy { 109 const char *name; 110 const char *hname; 111 struct list_head list; 112 struct list_head profiles; 113 }; 114 115 /** 116 * basename - find the last component of an hname 117 * @name: hname to find the base profile name component of (NOT NULL) 118 * 119 * Returns: the tail (base profile name) name component of an hname 120 */ 121 static inline const char *basename(const char *hname) 122 { 123 char *split; 124 125 hname = strim((char *)hname); 126 for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) 127 hname = split + 2; 128 129 return hname; 130 } 131 132 /** 133 * __policy_find - find a policy by @name on a policy list 134 * @head: list to search (NOT NULL) 135 * @name: name to search for (NOT NULL) 136 * 137 * Requires: rcu_read_lock be held 138 * 139 * Returns: unrefcounted policy that match @name or NULL if not found 140 */ 141 static inline struct aa_policy *__policy_find(struct list_head *head, 142 const char *name) 143 { 144 struct aa_policy *policy; 145 146 list_for_each_entry_rcu(policy, head, list) { 147 if (!strcmp(policy->name, name)) 148 return policy; 149 } 150 return NULL; 151 } 152 153 /** 154 * __policy_strn_find - find a policy that's name matches @len chars of @str 155 * @head: list to search (NOT NULL) 156 * @str: string to search for (NOT NULL) 157 * @len: length of match required 158 * 159 * Requires: rcu_read_lock be held 160 * 161 * Returns: unrefcounted policy that match @str or NULL if not found 162 * 163 * if @len == strlen(@strlen) then this is equiv to __policy_find 164 * other wise it allows searching for policy by a partial match of name 165 */ 166 static inline struct aa_policy *__policy_strn_find(struct list_head *head, 167 const char *str, int len) 168 { 169 struct aa_policy *policy; 170 171 list_for_each_entry_rcu(policy, head, list) { 172 if (aa_strneq(policy->name, str, len)) 173 return policy; 174 } 175 176 return NULL; 177 } 178 179 bool aa_policy_init(struct aa_policy *policy, const char *prefix, 180 const char *name, gfp_t gfp); 181 void aa_policy_destroy(struct aa_policy *policy); 182 183 #endif /* AA_LIB_H */ 184