linux/include/linux/uidgid.h
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   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
  17struct user_namespace;
  18extern struct user_namespace init_user_ns;
  19
  20#ifdef CONFIG_UIDGID_STRICT_TYPE_CHECKS
  21
  22typedef struct {
  23        uid_t val;
  24} kuid_t;
  25
  26
  27typedef 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
  34static inline uid_t __kuid_val(kuid_t uid)
  35{
  36        return uid.val;
  37}
  38
  39static inline gid_t __kgid_val(kgid_t gid)
  40{
  41        return gid.val;
  42}
  43
  44#else
  45
  46typedef uid_t kuid_t;
  47typedef gid_t kgid_t;
  48
  49static inline uid_t __kuid_val(kuid_t uid)
  50{
  51        return uid;
  52}
  53
  54static 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
  70static inline bool uid_eq(kuid_t left, kuid_t right)
  71{
  72        return __kuid_val(left) == __kuid_val(right);
  73}
  74
  75static inline bool gid_eq(kgid_t left, kgid_t right)
  76{
  77        return __kgid_val(left) == __kgid_val(right);
  78}
  79
  80static inline bool uid_gt(kuid_t left, kuid_t right)
  81{
  82        return __kuid_val(left) > __kuid_val(right);
  83}
  84
  85static inline bool gid_gt(kgid_t left, kgid_t right)
  86{
  87        return __kgid_val(left) > __kgid_val(right);
  88}
  89
  90static inline bool uid_gte(kuid_t left, kuid_t right)
  91{
  92        return __kuid_val(left) >= __kuid_val(right);
  93}
  94
  95static inline bool gid_gte(kgid_t left, kgid_t right)
  96{
  97        return __kgid_val(left) >= __kgid_val(right);
  98}
  99
 100static inline bool uid_lt(kuid_t left, kuid_t right)
 101{
 102        return __kuid_val(left) < __kuid_val(right);
 103}
 104
 105static inline bool gid_lt(kgid_t left, kgid_t right)
 106{
 107        return __kgid_val(left) < __kgid_val(right);
 108}
 109
 110static inline bool uid_lte(kuid_t left, kuid_t right)
 111{
 112        return __kuid_val(left) <= __kuid_val(right);
 113}
 114
 115static inline bool gid_lte(kgid_t left, kgid_t right)
 116{
 117        return __kgid_val(left) <= __kgid_val(right);
 118}
 119
 120static inline bool uid_valid(kuid_t uid)
 121{
 122        return !uid_eq(uid, INVALID_UID);
 123}
 124
 125static inline bool gid_valid(kgid_t gid)
 126{
 127        return !gid_eq(gid, INVALID_GID);
 128}
 129
 130#ifdef CONFIG_USER_NS
 131
 132extern kuid_t make_kuid(struct user_namespace *from, uid_t uid);
 133extern kgid_t make_kgid(struct user_namespace *from, gid_t gid);
 134
 135extern uid_t from_kuid(struct user_namespace *to, kuid_t uid);
 136extern gid_t from_kgid(struct user_namespace *to, kgid_t gid);
 137extern uid_t from_kuid_munged(struct user_namespace *to, kuid_t uid);
 138extern gid_t from_kgid_munged(struct user_namespace *to, kgid_t gid);
 139
 140static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
 141{
 142        return from_kuid(ns, uid) != (uid_t) -1;
 143}
 144
 145static 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
 152static inline kuid_t make_kuid(struct user_namespace *from, uid_t uid)
 153{
 154        return KUIDT_INIT(uid);
 155}
 156
 157static inline kgid_t make_kgid(struct user_namespace *from, gid_t gid)
 158{
 159        return KGIDT_INIT(gid);
 160}
 161
 162static inline uid_t from_kuid(struct user_namespace *to, kuid_t kuid)
 163{
 164        return __kuid_val(kuid);
 165}
 166
 167static inline gid_t from_kgid(struct user_namespace *to, kgid_t kgid)
 168{
 169        return __kgid_val(kgid);
 170}
 171
 172static 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
 180static 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
 188static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
 189{
 190        return true;
 191}
 192
 193static 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 */
 201
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