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 INVALID_UID KUIDT_INIT(-1)
  68 #define INVALID_GID KGIDT_INIT(-1)
  69
  70 static inline bool uid_eq(kuid_t left, kuid_t right)
  71 {
  72         return __kuid_val(left) == __kuid_val(right);
  73 }
  74
  75 static inline bool gid_eq(kgid_t left, kgid_t right)
  76 {
  77         return __kgid_val(left) == __kgid_val(right);
  78 }
  79
  80 static inline bool uid_gt(kuid_t left, kuid_t right)
  81 {
  82         return __kuid_val(left) > __kuid_val(right);
  83 }
  84
  85 static inline bool gid_gt(kgid_t left, kgid_t right)
  86 {
  87         return __kgid_val(left) > __kgid_val(right);
  88 }
  89
  90 static inline bool uid_gte(kuid_t left, kuid_t right)
  91 {
  92         return __kuid_val(left) >= __kuid_val(right);
  93 }
  94
  95 static inline bool gid_gte(kgid_t left, kgid_t right)
  96 {
  97         return __kgid_val(left) >= __kgid_val(right);
  98 }
  99
 100 static inline bool uid_lt(kuid_t left, kuid_t right)
 101 {
 102         return __kuid_val(left) < __kuid_val(right);
 103 }
 104
 105 static inline bool gid_lt(kgid_t left, kgid_t right)
 106 {
 107         return __kgid_val(left) < __kgid_val(right);
 108 }
 109
 110 static inline bool uid_lte(kuid_t left, kuid_t right)
 111 {
 112         return __kuid_val(left) <= __kuid_val(right);
 113 }
 114
 115 static inline bool gid_lte(kgid_t left, kgid_t right)
 116 {
 117         return __kgid_val(left) <= __kgid_val(right);
 118 }
 119
 120 static inline bool uid_valid(kuid_t uid)
 121 {
 122         return !uid_eq(uid, INVALID_UID);
 123 }
 124
 125 static inline bool gid_valid(kgid_t gid)
 126 {
 127         return !gid_eq(gid, INVALID_GID);
 128 }
 129
 130 #ifdef CONFIG_USER_NS
 131
 132 extern kuid_t make_kuid(struct user_namespace *from, uid_t uid);
 133 extern kgid_t make_kgid(struct user_namespace *from, gid_t gid);
 134
 135 extern uid_t from_kuid(struct user_namespace *to, kuid_t uid);
 136 extern gid_t from_kgid(struct user_namespace *to, kgid_t gid);
 137 extern uid_t from_kuid_munged(struct user_namespace *to, kuid_t uid);
 138 extern gid_t from_kgid_munged(struct user_namespace *to, kgid_t gid);
 139
 140 static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
 141 {
 142         return from_kuid(ns, uid) != (uid_t) -1;
 143 }
 144
 145 static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
 146 {
 147         return from_kgid(ns, gid) != (gid_t) -1;
 148 }
 149
 150 #else
 151
 152 static inline kuid_t make_kuid(struct user_namespace *from, uid_t uid)
 153 {
 154         return KUIDT_INIT(uid);
 155 }
 156
 157 static inline kgid_t make_kgid(struct user_namespace *from, gid_t gid)
 158 {
 159         return KGIDT_INIT(gid);
 160 }
 161
 162 static inline uid_t from_kuid(struct user_namespace *to, kuid_t kuid)
 163 {
 164         return __kuid_val(kuid);
 165 }
 166
 167 static inline gid_t from_kgid(struct user_namespace *to, kgid_t kgid)
 168 {
 169         return __kgid_val(kgid);
 170 }
 171
 172 static inline uid_t from_kuid_munged(struct user_namespace *to, kuid_t kuid)
 173 {
 174         uid_t uid = from_kuid(to, kuid);
 175         if (uid == (uid_t)-1)
 176                 uid = overflowuid;
 177         return uid;
 178 }
 179
 180 static inline gid_t from_kgid_munged(struct user_namespace *to, kgid_t kgid)
 181 {
 182         gid_t gid = from_kgid(to, kgid);
 183         if (gid == (gid_t)-1)
 184                 gid = overflowgid;
 185         return gid;
 186 }
 187
 188 static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
 189 {
 190         return true;
 191 }
 192
 193 static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
 194 {
 195         return true;
 196 }
 197
 198 #endif /* CONFIG_USER_NS */
 199
 200 #endif /* _LINUX_UIDGID_H */