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kernel/linux-rt-4.4.41/include/linux/user_namespace.h 2.63 KB
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  #ifndef _LINUX_USER_NAMESPACE_H
  #define _LINUX_USER_NAMESPACE_H
  
  #include <linux/kref.h>
  #include <linux/nsproxy.h>
  #include <linux/ns_common.h>
  #include <linux/sched.h>
  #include <linux/err.h>
  
  #define UID_GID_MAP_MAX_EXTENTS 5
  
  struct uid_gid_map {	/* 64 bytes -- 1 cache line */
  	u32 nr_extents;
  	struct uid_gid_extent {
  		u32 first;
  		u32 lower_first;
  		u32 count;
  	} extent[UID_GID_MAP_MAX_EXTENTS];
  };
  
  #define USERNS_SETGROUPS_ALLOWED 1UL
  
  #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
  
  struct user_namespace {
  	struct uid_gid_map	uid_map;
  	struct uid_gid_map	gid_map;
  	struct uid_gid_map	projid_map;
  	atomic_t		count;
  	struct user_namespace	*parent;
  	int			level;
  	kuid_t			owner;
  	kgid_t			group;
  	struct ns_common	ns;
  	unsigned long		flags;
  
  	/* Register of per-UID persistent keyrings for this namespace */
  #ifdef CONFIG_PERSISTENT_KEYRINGS
  	struct key		*persistent_keyring_register;
  	struct rw_semaphore	persistent_keyring_register_sem;
  #endif
  };
  
  extern struct user_namespace init_user_ns;
  
  #ifdef CONFIG_USER_NS
  
  static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  {
  	if (ns)
  		atomic_inc(&ns->count);
  	return ns;
  }
  
  extern int create_user_ns(struct cred *new);
  extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  extern void free_user_ns(struct user_namespace *ns);
  
  static inline void put_user_ns(struct user_namespace *ns)
  {
  	if (ns && atomic_dec_and_test(&ns->count))
  		free_user_ns(ns);
  }
  
  struct seq_operations;
  extern const struct seq_operations proc_uid_seq_operations;
  extern const struct seq_operations proc_gid_seq_operations;
  extern const struct seq_operations proc_projid_seq_operations;
  extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
  extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
  extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
  extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
  extern int proc_setgroups_show(struct seq_file *m, void *v);
  extern bool userns_may_setgroups(const struct user_namespace *ns);
  #else
  
  static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  {
  	return &init_user_ns;
  }
  
  static inline int create_user_ns(struct cred *new)
  {
  	return -EINVAL;
  }
  
  static inline int unshare_userns(unsigned long unshare_flags,
  				 struct cred **new_cred)
  {
  	if (unshare_flags & CLONE_NEWUSER)
  		return -EINVAL;
  	return 0;
  }
  
  static inline void put_user_ns(struct user_namespace *ns)
  {
  }
  
  static inline bool userns_may_setgroups(const struct user_namespace *ns)
  {
  	return true;
  }
  #endif
  
  #endif /* _LINUX_USER_H */