Line data    Source code

       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           0 :         return !projid_eq(projid, INVALID_PROJID);
      49             : }
      50             : 
      51             : #ifdef CONFIG_USER_NS
      52             : 
      53             : extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);
      54             : 
      55             : extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
      56             : extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);
      57             : 
      58             : static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
      59             : {
      60             :         return from_kprojid(ns, projid) != (projid_t)-1;
      61             : }
      62             : 
      63             : #else
      64             : 
      65             : static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
      66             : {
      67             :         return KPROJIDT_INIT(projid);
      68             : }
      69             : 
      70             : static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
      71             : {
      72             :         return __kprojid_val(kprojid);
      73             : }
      74             : 
      75             : static inline projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t kprojid)
      76             : {
      77             :         projid_t projid = from_kprojid(to, kprojid);
      78             :         if (projid == (projid_t)-1)
      79             :                 projid = OVERFLOW_PROJID;
      80             :         return projid;
      81             : }
      82             : 
      83             : static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
      84             : {
      85             :         return true;
      86             : }
      87             : 
      88             : #endif /* CONFIG_USER_NS */
      89             : 
      90             : #endif /* _LINUX_PROJID_H */