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 #define USERNS_SETGROUPS_ALLOWED 1UL
  21
  22 #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
  23
  24 struct user_namespace {
  25         struct uid_gid_map      uid_map;
  26         struct uid_gid_map      gid_map;
  27         struct uid_gid_map      projid_map;
  28         atomic_t                count;
  29         struct user_namespace   *parent;
  30         int                     level;
  31         kuid_t                  owner;
  32         kgid_t                  group;
  33         unsigned int            proc_inum;
  34         unsigned long           flags;
  35         bool                    may_mount_sysfs;
  36         bool                    may_mount_proc;
  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 struct seq_operations proc_uid_seq_operations;
  62 extern struct seq_operations proc_gid_seq_operations;
  63 extern 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 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
  68 extern int proc_setgroups_show(struct seq_file *m, void *v);
  69 extern bool userns_may_setgroups(const struct user_namespace *ns);
  70 #else
  71
  72 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  73 {
  74         return &init_user_ns;
  75 }
  76
  77 static inline int create_user_ns(struct cred *new)
  78 {
  79         return -EINVAL;
  80 }
  81
  82 static inline int unshare_userns(unsigned long unshare_flags,
  83                                  struct cred **new_cred)
  84 {
  85         if (unshare_flags & CLONE_NEWUSER)
  86                 return -EINVAL;
  87         return 0;
  88 }
  89
  90 static inline void put_user_ns(struct user_namespace *ns)
  91 {
  92 }
  93
  94 static inline bool userns_may_setgroups(const struct user_namespace *ns)
  95 {
  96         return true;
  97 }
  98 #endif
  99
 100 void update_mnt_policy(struct user_namespace *userns);
 101
 102 #endif /* _LINUX_USER_H */