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 #ifdef CONFIG_UIDGID_STRICT_TYPE_CHECKS
  21
  22 typedef struct {
  23         uid_t val;
  24 } kuid_t;
  25
  26
  27 typedef struct {
  28         gid_t val;
  29 } kgid_t;
  30
  31 #define KUIDT_INIT(value) (kuid_t){ value }
  32 #define KGIDT_INIT(value) (kgid_t){ value }
  33
  34 static inline uid_t __kuid_val(kuid_t uid)
  35 {
  36         return uid.val;
  37 }
  38
  39 static inline gid_t __kgid_val(kgid_t gid)
  40 {
  41         return gid.val;
  42 }
  43
  44 #else
  45
  46 typedef uid_t kuid_t;
  47 typedef gid_t kgid_t;
  48
  49 static inline uid_t __kuid_val(kuid_t uid)
  50 {
  51         return uid;
  52 }
  53
  54 static inline gid_t __kgid_val(kgid_t gid)
  55 {
  56         return gid;
  57 }
  58
  59 #define KUIDT_INIT(value) ((kuid_t) value )
  60 #define KGIDT_INIT(value) ((kgid_t) value )
  61
  62 #endif
  63
  64 #define GLOBAL_ROOT_UID KUIDT_INIT(0)
  65 #define GLOBAL_ROOT_GID KGIDT_INIT(0)
  66
  67 #define GLOBAL_SYSTEM_UID KUIDT_INIT(1000)
  68 #define GLOBAL_SYSTEM_GID KGIDT_INIT(1000)
  69
  70 #define INVALID_UID KUIDT_INIT(-1)
  71 #define INVALID_GID KGIDT_INIT(-1)
  72
  73 static inline bool uid_eq(kuid_t left, kuid_t right)
  74 {
  75         return __kuid_val(left) == __kuid_val(right);
  76 }
  77
  78 static inline bool gid_eq(kgid_t left, kgid_t right)
  79 {
  80         return __kgid_val(left) == __kgid_val(right);
  81 }
  82
  83 static inline bool uid_gt(kuid_t left, kuid_t right)
  84 {
  85         return __kuid_val(left) > __kuid_val(right);
  86 }
  87
  88 static inline bool gid_gt(kgid_t left, kgid_t right)
  89 {
  90         return __kgid_val(left) > __kgid_val(right);
  91 }
  92
  93 static inline bool uid_gte(kuid_t left, kuid_t right)
  94 {
  95         return __kuid_val(left) >= __kuid_val(right);
  96 }
  97
  98 static inline bool gid_gte(kgid_t left, kgid_t right)
  99 {
 100         return __kgid_val(left) >= __kgid_val(right);
 101 }
 102
 103 static inline bool uid_lt(kuid_t left, kuid_t right)
 104 {
 105         return __kuid_val(left) < __kuid_val(right);
 106 }
 107
 108 static inline bool gid_lt(kgid_t left, kgid_t right)
 109 {
 110         return __kgid_val(left) < __kgid_val(right);
 111 }
 112
 113 static inline bool uid_lte(kuid_t left, kuid_t right)
 114 {
 115         return __kuid_val(left) <= __kuid_val(right);
 116 }
 117
 118 static inline bool gid_lte(kgid_t left, kgid_t right)
 119 {
 120         return __kgid_val(left) <= __kgid_val(right);
 121 }
 122
 123 static inline bool uid_valid(kuid_t uid)
 124 {
 125         return !uid_eq(uid, INVALID_UID);
 126 }
 127
 128 static inline bool gid_valid(kgid_t gid)
 129 {
 130         return !gid_eq(gid, INVALID_GID);
 131 }
 132
 133 #ifdef CONFIG_USER_NS
 134
 135 extern kuid_t make_kuid(struct user_namespace *from, uid_t uid);
 136 extern kgid_t make_kgid(struct user_namespace *from, gid_t gid);
 137
 138 extern uid_t from_kuid(struct user_namespace *to, kuid_t uid);
 139 extern gid_t from_kgid(struct user_namespace *to, kgid_t gid);
 140 extern uid_t from_kuid_munged(struct user_namespace *to, kuid_t uid);
 141 extern gid_t from_kgid_munged(struct user_namespace *to, kgid_t gid);
 142
 143 static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
 144 {
 145         return from_kuid(ns, uid) != (uid_t) -1;
 146 }
 147
 148 static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
 149 {
 150         return from_kgid(ns, gid) != (gid_t) -1;
 151 }
 152
 153 #else
 154
 155 static inline kuid_t make_kuid(struct user_namespace *from, uid_t uid)
 156 {
 157         return KUIDT_INIT(uid);
 158 }
 159
 160 static inline kgid_t make_kgid(struct user_namespace *from, gid_t gid)
 161 {
 162         return KGIDT_INIT(gid);
 163 }
 164
 165 static inline uid_t from_kuid(struct user_namespace *to, kuid_t kuid)
 166 {
 167         return __kuid_val(kuid);
 168 }
 169
 170 static inline gid_t from_kgid(struct user_namespace *to, kgid_t kgid)
 171 {
 172         return __kgid_val(kgid);
 173 }
 174
 175 static inline uid_t from_kuid_munged(struct user_namespace *to, kuid_t kuid)
 176 {
 177         uid_t uid = from_kuid(to, kuid);
 178         if (uid == (uid_t)-1)
 179                 uid = overflowuid;
 180         return uid;
 181 }
 182
 183 static inline gid_t from_kgid_munged(struct user_namespace *to, kgid_t kgid)
 184 {
 185         gid_t gid = from_kgid(to, kgid);
 186         if (gid == (gid_t)-1)
 187                 gid = overflowgid;
 188         return gid;
 189 }
 190
 191 static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
 192 {
 193         return true;
 194 }
 195
 196 static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
 197 {
 198         return true;
 199 }
 200
 201 #endif /* CONFIG_USER_NS */
 202
 203 #endif /* _LINUX_UIDGID_H */