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