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         int                     level;
  27         kuid_t                  owner;
  28         kgid_t                  group;
  29         unsigned int            proc_inum;
  30 };
  31
  32 extern struct user_namespace init_user_ns;
  33
  34 #ifdef CONFIG_USER_NS
  35
  36 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  37 {
  38         if (ns)
  39                 atomic_inc(&ns->count);
  40         return ns;
  41 }
  42
  43 extern int create_user_ns(struct cred *new);
  44 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  45 extern void free_user_ns(struct user_namespace *ns);
  46
  47 static inline void put_user_ns(struct user_namespace *ns)
  48 {
  49         if (ns && atomic_dec_and_test(&ns->count))
  50                 free_user_ns(ns);
  51 }
  52
  53 struct seq_operations;
  54 extern struct seq_operations proc_uid_seq_operations;
  55 extern struct seq_operations proc_gid_seq_operations;
  56 extern struct seq_operations proc_projid_seq_operations;
  57 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
  58 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
  59 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
  60 #else
  61
  62 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  63 {
  64         return &init_user_ns;
  65 }
  66
  67 static inline int create_user_ns(struct cred *new)
  68 {
  69         return -EINVAL;
  70 }
  71
  72 static inline int unshare_userns(unsigned long unshare_flags,
  73                                  struct cred **new_cred)
  74 {
  75         if (unshare_flags & CLONE_NEWUSER)
  76                 return -EINVAL;
  77         return 0;
  78 }
  79
  80 static inline void put_user_ns(struct user_namespace *ns)
  81 {
  82 }
  83
  84 #endif
  85
  86 #endif /* _LINUX_USER_H */