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