include/linux/uidgid.h

   1 #ifndef _LINUX_UIDGID_H
   2 #define _LINUX_UIDGID_H
   3
   4 /*
   5  * A set of types for the internal kernel types representing uids and gids.
   6  *
   7  * The types defined in this header allow distinguishing which uids and gids in
   8  * the kernel are values used by userspace and which uid and gid values are
   9  * the internal kernel values.  With the addition of user namespaces the values
  10  * can be different.  Using the type system makes it possible for the compiler
  11  * to detect when we overlook these differences.
  12  *
  13  */
  14 #include <linux/types.h>
  15 #include <linux/highuid.h>
  16
  17 struct user_namespace;
  18 extern struct user_namespace init_user_ns;
  19
  20 typedef struct {
  21         uid_t val;
  22 } kuid_t;
  23
  24
  25 typedef struct {
  26         gid_t val;
  27 } kgid_t;
  28
  29 #define KUIDT_INIT(value) (kuid_t){ value }
  30 #define KGIDT_INIT(value) (kgid_t){ value }
  31
  32 #ifdef CONFIG_MULTIUSER
  33 static inline uid_t __kuid_val(kuid_t uid)
  34 {
  35         return uid.val;
  36 }
  37
  38 static inline gid_t __kgid_val(kgid_t gid)
  39 {
  40         return gid.val;
  41 }
  42 #else
  43 static inline uid_t __kuid_val(kuid_t uid)
  44 {
  45         return 0;
  46 }
  47
  48 static inline gid_t __kgid_val(kgid_t gid)
  49 {
  50         return 0;
  51 }
  52 #endif
  53
  54 #define GLOBAL_ROOT_UID KUIDT_INIT(0)
  55 #define GLOBAL_ROOT_GID KGIDT_INIT(0)
  56
  57 #define INVALID_UID KUIDT_INIT(-1)
  58 #define INVALID_GID KGIDT_INIT(-1)
  59
  60 static inline bool uid_eq(kuid_t left, kuid_t right)
  61 {
  62         return __kuid_val(left) == __kuid_val(right);
  63 }
  64
  65 static inline bool gid_eq(kgid_t left, kgid_t right)
  66 {
  67         return __kgid_val(left) == __kgid_val(right);
  68 }
  69
  70 static inline bool uid_gt(kuid_t left, kuid_t right)
  71 {
  72         return __kuid_val(left) > __kuid_val(right);
  73 }
  74
  75 static inline bool gid_gt(kgid_t left, kgid_t right)
  76 {
  77         return __kgid_val(left) > __kgid_val(right);
  78 }
  79
  80 static inline bool uid_gte(kuid_t left, kuid_t right)
  81 {
  82         return __kuid_val(left) >= __kuid_val(right);
  83 }
  84
  85 static inline bool gid_gte(kgid_t left, kgid_t right)
  86 {
  87         return __kgid_val(left) >= __kgid_val(right);
  88 }
  89
  90 static inline bool uid_lt(kuid_t left, kuid_t right)
  91 {
  92         return __kuid_val(left) < __kuid_val(right);
  93 }
  94
  95 static inline bool gid_lt(kgid_t left, kgid_t right)
  96 {
  97         return __kgid_val(left) < __kgid_val(right);
  98 }
  99
 100 static inline bool uid_lte(kuid_t left, kuid_t right)
 101 {
 102         return __kuid_val(left) <= __kuid_val(right);
 103 }
 104
 105 static inline bool gid_lte(kgid_t left, kgid_t right)
 106 {
 107         return __kgid_val(left) <= __kgid_val(right);
 108 }
 109
 110 static inline bool uid_valid(kuid_t uid)
 111 {
 112         return __kuid_val(uid) != (uid_t) -1;
 113 }
 114
 115 static inline bool gid_valid(kgid_t gid)
 116 {
 117         return __kgid_val(gid) != (gid_t) -1;
 118 }
 119
 120 #ifdef CONFIG_USER_NS
 121
 122 extern kuid_t make_kuid(struct user_namespace *from, uid_t uid);
 123 extern kgid_t make_kgid(struct user_namespace *from, gid_t gid);
 124
 125 extern uid_t from_kuid(struct user_namespace *to, kuid_t uid);
 126 extern gid_t from_kgid(struct user_namespace *to, kgid_t gid);
 127 extern uid_t from_kuid_munged(struct user_namespace *to, kuid_t uid);
 128 extern gid_t from_kgid_munged(struct user_namespace *to, kgid_t gid);
 129
 130 static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
 131 {
 132         return from_kuid(ns, uid) != (uid_t) -1;
 133 }
 134
 135 static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
 136 {
 137         return from_kgid(ns, gid) != (gid_t) -1;
 138 }
 139
 140 #else
 141
 142 static inline kuid_t make_kuid(struct user_namespace *from, uid_t uid)
 143 {
 144         return KUIDT_INIT(uid);
 145 }
 146
 147 static inline kgid_t make_kgid(struct user_namespace *from, gid_t gid)
 148 {
 149         return KGIDT_INIT(gid);
 150 }
 151
 152 static inline uid_t from_kuid(struct user_namespace *to, kuid_t kuid)
 153 {
 154         return __kuid_val(kuid);
 155 }
 156
 157 static inline gid_t from_kgid(struct user_namespace *to, kgid_t kgid)
 158 {
 159         return __kgid_val(kgid);
 160 }
 161
 162 static inline uid_t from_kuid_munged(struct user_namespace *to, kuid_t kuid)
 163 {
 164         uid_t uid = from_kuid(to, kuid);
 165         if (uid == (uid_t)-1)
 166                 uid = overflowuid;
 167         return uid;
 168 }
 169
 170 static inline gid_t from_kgid_munged(struct user_namespace *to, kgid_t kgid)
 171 {
 172         gid_t gid = from_kgid(to, kgid);
 173         if (gid == (gid_t)-1)
 174                 gid = overflowgid;
 175         return gid;
 176 }
 177
 178 static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
 179 {
 180         return true;
 181 }
 182
 183 static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
 184 {
 185         return true;
 186 }
 187
 188 #endif /* CONFIG_USER_NS */
 189
 190 #endif /* _LINUX_UIDGID_H */