security/apparmor/include/lib.h

   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 __initdata;
  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 void *__aa_kvmalloc(size_t size, gfp_t flags);
  68
  69 static inline void *kvmalloc(size_t size)
  70 {
  71         return __aa_kvmalloc(size, 0);
  72 }
  73
  74 static inline void *kvzalloc(size_t size)
  75 {
  76         return __aa_kvmalloc(size, __GFP_ZERO);
  77 }
  78
  79 /**
  80  * aa_strneq - compare null terminated @str to a non null terminated substring
  81  * @str: a null terminated string
  82  * @sub: a substring, not necessarily null terminated
  83  * @len: length of @sub to compare
  84  *
  85  * The @str string must be full consumed for this to be considered a match
  86  */
  87 static inline bool aa_strneq(const char *str, const char *sub, int len)
  88 {
  89         return !strncmp(str, sub, len) && !str[len];
  90 }
  91
  92 /**
  93  * aa_dfa_null_transition - step to next state after null character
  94  * @dfa: the dfa to match against
  95  * @start: the state of the dfa to start matching in
  96  *
  97  * aa_dfa_null_transition transitions to the next state after a null
  98  * character which is not used in standard matching and is only
  99  * used to separate pairs.
 100  */
 101 static inline unsigned int aa_dfa_null_transition(struct aa_dfa *dfa,
 102                                                   unsigned int start)
 103 {
 104         /* the null transition only needs the string's null terminator byte */
 105         return aa_dfa_next(dfa, start, 0);
 106 }
 107
 108 static inline bool path_mediated_fs(struct dentry *dentry)
 109 {
 110         return !(dentry->d_sb->s_flags & MS_NOUSER);
 111 }
 112
 113 /* struct aa_policy - common part of both namespaces and profiles
 114  * @name: name of the object
 115  * @hname - The hierarchical name
 116  * @list: list policy object is on
 117  * @profiles: head of the profiles list contained in the object
 118  */
 119 struct aa_policy {
 120         const char *name;
 121         const char *hname;
 122         struct list_head list;
 123         struct list_head profiles;
 124 };
 125
 126 /**
 127  * basename - find the last component of an hname
 128  * @name: hname to find the base profile name component of  (NOT NULL)
 129  *
 130  * Returns: the tail (base profile name) name component of an hname
 131  */
 132 static inline const char *basename(const char *hname)
 133 {
 134         char *split;
 135
 136         hname = strim((char *)hname);
 137         for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
 138                 hname = split + 2;
 139
 140         return hname;
 141 }
 142
 143 /**
 144  * __policy_find - find a policy by @name on a policy list
 145  * @head: list to search  (NOT NULL)
 146  * @name: name to search for  (NOT NULL)
 147  *
 148  * Requires: rcu_read_lock be held
 149  *
 150  * Returns: unrefcounted policy that match @name or NULL if not found
 151  */
 152 static inline struct aa_policy *__policy_find(struct list_head *head,
 153                                               const char *name)
 154 {
 155         struct aa_policy *policy;
 156
 157         list_for_each_entry_rcu(policy, head, list) {
 158                 if (!strcmp(policy->name, name))
 159                         return policy;
 160         }
 161         return NULL;
 162 }
 163
 164 /**
 165  * __policy_strn_find - find a policy that's name matches @len chars of @str
 166  * @head: list to search  (NOT NULL)
 167  * @str: string to search for  (NOT NULL)
 168  * @len: length of match required
 169  *
 170  * Requires: rcu_read_lock be held
 171  *
 172  * Returns: unrefcounted policy that match @str or NULL if not found
 173  *
 174  * if @len == strlen(@strlen) then this is equiv to __policy_find
 175  * other wise it allows searching for policy by a partial match of name
 176  */
 177 static inline struct aa_policy *__policy_strn_find(struct list_head *head,
 178                                             const char *str, int len)
 179 {
 180         struct aa_policy *policy;
 181
 182         list_for_each_entry_rcu(policy, head, list) {
 183                 if (aa_strneq(policy->name, str, len))
 184                         return policy;
 185         }
 186
 187         return NULL;
 188 }
 189
 190 bool aa_policy_init(struct aa_policy *policy, const char *prefix,
 191                     const char *name, gfp_t gfp);
 192 void aa_policy_destroy(struct aa_policy *policy);
 193
 194 #endif /* AA_LIB_H */