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         /* Register of per-UID persistent keyrings for this namespace */
  32 #ifdef CONFIG_PERSISTENT_KEYRINGS
  33         struct key              *persistent_keyring_register;
  34         struct rw_semaphore     persistent_keyring_register_sem;
  35 #endif
  36 };
  37
  38 extern struct user_namespace init_user_ns;
  39
  40 #ifdef CONFIG_USER_NS
  41
  42 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  43 {
  44         if (ns)
  45                 atomic_inc(&ns->count);
  46         return ns;
  47 }
  48
  49 extern int create_user_ns(struct cred *new);
  50 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  51 extern void free_user_ns(struct user_namespace *ns);
  52
  53 static inline void put_user_ns(struct user_namespace *ns)
  54 {
  55         if (ns && atomic_dec_and_test(&ns->count))
  56                 free_user_ns(ns);
  57 }
  58
  59 struct seq_operations;
  60 extern struct seq_operations proc_uid_seq_operations;
  61 extern struct seq_operations proc_gid_seq_operations;
  62 extern struct seq_operations proc_projid_seq_operations;
  63 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
  64 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
  65 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
  66 #else
  67
  68 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  69 {
  70         return &init_user_ns;
  71 }
  72
  73 static inline int create_user_ns(struct cred *new)
  74 {
  75         return -EINVAL;
  76 }
  77
  78 static inline int unshare_userns(unsigned long unshare_flags,
  79                                  struct cred **new_cred)
  80 {
  81         if (unshare_flags & CLONE_NEWUSER)
  82                 return -EINVAL;
  83         return 0;
  84 }
  85
  86 static inline void put_user_ns(struct user_namespace *ns)
  87 {
  88 }
  89
  90 #endif
  91
  92 #endif /* _LINUX_USER_H */