include/linux/user_namespace.h

   1 #ifndef _LINUX_USER_NAMESPACE_H
   2 #define _LINUX_USER_NAMESPACE_H
   3
   4 #include <linux/kref.h>
   5 #include <linux/nsproxy.h>
   6 #include <linux/ns_common.h>
   7 #include <linux/sched.h>
   8 #include <linux/err.h>
   9
  10 #define UID_GID_MAP_MAX_EXTENTS 5
  11
  12 struct uid_gid_map {    /* 64 bytes -- 1 cache line */
  13         u32 nr_extents;
  14         struct uid_gid_extent {
  15                 u32 first;
  16                 u32 lower_first;
  17                 u32 count;
  18         } extent[UID_GID_MAP_MAX_EXTENTS];
  19 };
  20
  21 struct user_namespace {
  22         struct uid_gid_map      uid_map;
  23         struct uid_gid_map      gid_map;
  24         struct uid_gid_map      projid_map;
  25         atomic_t                count;
  26         struct user_namespace   *parent;
  27         int                     level;
  28         kuid_t                  owner;
  29         kgid_t                  group;
  30         struct ns_common        ns;
  31
  32         /* Register of per-UID persistent keyrings for this namespace */
  33 #ifdef CONFIG_PERSISTENT_KEYRINGS
  34         struct key              *persistent_keyring_register;
  35         struct rw_semaphore     persistent_keyring_register_sem;
  36 #endif
  37 };
  38
  39 extern struct user_namespace init_user_ns;
  40
  41 #ifdef CONFIG_USER_NS
  42
  43 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  44 {
  45         if (ns)
  46                 atomic_inc(&ns->count);
  47         return ns;
  48 }
  49
  50 extern int create_user_ns(struct cred *new);
  51 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  52 extern void free_user_ns(struct user_namespace *ns);
  53
  54 static inline void put_user_ns(struct user_namespace *ns)
  55 {
  56         if (ns && atomic_dec_and_test(&ns->count))
  57                 free_user_ns(ns);
  58 }
  59
  60 struct seq_operations;
  61 extern const struct seq_operations proc_uid_seq_operations;
  62 extern const struct seq_operations proc_gid_seq_operations;
  63 extern const struct seq_operations proc_projid_seq_operations;
  64 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
  65 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
  66 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
  67 #else
  68
  69 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  70 {
  71         return &init_user_ns;
  72 }
  73
  74 static inline int create_user_ns(struct cred *new)
  75 {
  76         return -EINVAL;
  77 }
  78
  79 static inline int unshare_userns(unsigned long unshare_flags,
  80                                  struct cred **new_cred)
  81 {
  82         if (unshare_flags & CLONE_NEWUSER)
  83                 return -EINVAL;
  84         return 0;
  85 }
  86
  87 static inline void put_user_ns(struct user_namespace *ns)
  88 {
  89 }
  90
  91 #endif
  92
  93 #endif /* _LINUX_USER_H */