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/ns_common.h>
   7 #include <linux/sched.h>
   8 #include <linux/err.h>
   9
  10 #define UID_GID_MAP_MAX_EXTENTS 5
  11
  12 struct uid_gid_map {    /* 64 bytes -- 1 cache line */
  13         u32 nr_extents;
  14         struct uid_gid_extent {
  15                 u32 first;
  16                 u32 lower_first;
  17                 u32 count;
  18         } extent[UID_GID_MAP_MAX_EXTENTS];
  19 };
  20
  21 #define USERNS_SETGROUPS_ALLOWED 1UL
  22
  23 #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
  24
  25 struct user_namespace {
  26         struct uid_gid_map      uid_map;
  27         struct uid_gid_map      gid_map;
  28         struct uid_gid_map      projid_map;
  29         atomic_t                count;
  30         struct user_namespace   *parent;
  31         int                     level;
  32         kuid_t                  owner;
  33         kgid_t                  group;
  34         struct ns_common        ns;
  35         unsigned long           flags;
  36
  37         /* Register of per-UID persistent keyrings for this namespace */
  38 #ifdef CONFIG_PERSISTENT_KEYRINGS
  39         struct key              *persistent_keyring_register;
  40         struct rw_semaphore     persistent_keyring_register_sem;
  41 #endif
  42 };
  43
  44 extern struct user_namespace init_user_ns;
  45
  46 #ifdef CONFIG_USER_NS
  47
  48 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  49 {
  50         if (ns)
  51                 atomic_inc(&ns->count);
  52         return ns;
  53 }
  54
  55 extern int create_user_ns(struct cred *new);
  56 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  57 extern void free_user_ns(struct user_namespace *ns);
  58
  59 static inline void put_user_ns(struct user_namespace *ns)
  60 {
  61         if (ns && atomic_dec_and_test(&ns->count))
  62                 free_user_ns(ns);
  63 }
  64
  65 struct seq_operations;
  66 extern const struct seq_operations proc_uid_seq_operations;
  67 extern const struct seq_operations proc_gid_seq_operations;
  68 extern const struct seq_operations proc_projid_seq_operations;
  69 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
  70 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
  71 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
  72 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
  73 extern int proc_setgroups_show(struct seq_file *m, void *v);
  74 extern bool userns_may_setgroups(const struct user_namespace *ns);
  75 #else
  76
  77 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  78 {
  79         return &init_user_ns;
  80 }
  81
  82 static inline int create_user_ns(struct cred *new)
  83 {
  84         return -EINVAL;
  85 }
  86
  87 static inline int unshare_userns(unsigned long unshare_flags,
  88                                  struct cred **new_cred)
  89 {
  90         if (unshare_flags & CLONE_NEWUSER)
  91                 return -EINVAL;
  92         return 0;
  93 }
  94
  95 static inline void put_user_ns(struct user_namespace *ns)
  96 {
  97 }
  98
  99 static inline bool userns_may_setgroups(const struct user_namespace *ns)
 100 {
 101         return true;
 102 }
 103 #endif
 104
 105 #endif /* _LINUX_USER_H */