include/linux/projid.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_PROJID_H
   3 #define _LINUX_PROJID_H
   4
   5 /*
   6  * A set of types for the internal kernel types representing project ids.
   7  *
   8  * The types defined in this header allow distinguishing which project ids in
   9  * the kernel are values used by userspace and which project id values are
  10  * the internal kernel values.  With the addition of user namespaces the values
  11  * can be different.  Using the type system makes it possible for the compiler
  12  * to detect when we overlook these differences.
  13  *
  14  */
  15 #include <linux/types.h>
  16
  17 struct user_namespace;
  18 extern struct user_namespace init_user_ns;
  19
  20 typedef __kernel_uid32_t projid_t;
  21
  22 typedef struct {
  23         projid_t val;
  24 } kprojid_t;
  25
  26 static inline projid_t __kprojid_val(kprojid_t projid)
  27 {
  28         return projid.val;
  29 }
  30
  31 #define KPROJIDT_INIT(value) (kprojid_t){ value }
  32
  33 #define INVALID_PROJID KPROJIDT_INIT(-1)
  34 #define OVERFLOW_PROJID 65534
  35
  36 static inline bool projid_eq(kprojid_t left, kprojid_t right)
  37 {
  38         return __kprojid_val(left) == __kprojid_val(right);
  39 }
  40
  41 static inline bool projid_lt(kprojid_t left, kprojid_t right)
  42 {
  43         return __kprojid_val(left) < __kprojid_val(right);
  44 }
  45
  46 static inline bool projid_valid(kprojid_t projid)
  47 {
  48         return !projid_eq(projid, INVALID_PROJID);
  49 }
  50
  51 static inline bool projid_valid_eq(kprojid_t left, kprojid_t right)
  52 {
  53         return projid_eq(left, right) && projid_valid(left);
  54 }
  55
  56 #ifdef CONFIG_USER_NS
  57
  58 extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);
  59
  60 extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
  61 extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);
  62
  63 static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
  64 {
  65         return from_kprojid(ns, projid) != (projid_t)-1;
  66 }
  67
  68 #else
  69
  70 static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
  71 {
  72         return KPROJIDT_INIT(projid);
  73 }
  74
  75 static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
  76 {
  77         return __kprojid_val(kprojid);
  78 }
  79
  80 static inline projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t kprojid)
  81 {
  82         projid_t projid = from_kprojid(to, kprojid);
  83         if (projid == (projid_t)-1)
  84                 projid = OVERFLOW_PROJID;
  85         return projid;
  86 }
  87
  88 static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
  89 {
  90         return true;
  91 }
  92
  93 #endif /* CONFIG_USER_NS */
  94
  95 #endif /* _LINUX_PROJID_H */