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 ucounts;
  26
  27 enum ucount_type {
  28         UCOUNT_USER_NAMESPACES,
  29         UCOUNT_PID_NAMESPACES,
  30         UCOUNT_UTS_NAMESPACES,
  31         UCOUNT_IPC_NAMESPACES,
  32         UCOUNT_COUNTS,
  33 };
  34
  35 struct user_namespace {
  36         struct uid_gid_map      uid_map;
  37         struct uid_gid_map      gid_map;
  38         struct uid_gid_map      projid_map;
  39         atomic_t                count;
  40         struct user_namespace   *parent;
  41         int                     level;
  42         kuid_t                  owner;
  43         kgid_t                  group;
  44         struct ns_common        ns;
  45         unsigned long           flags;
  46
  47         /* Register of per-UID persistent keyrings for this namespace */
  48 #ifdef CONFIG_PERSISTENT_KEYRINGS
  49         struct key              *persistent_keyring_register;
  50         struct rw_semaphore     persistent_keyring_register_sem;
  51 #endif
  52         struct work_struct      work;
  53 #ifdef CONFIG_SYSCTL
  54         struct ctl_table_set    set;
  55         struct ctl_table_header *sysctls;
  56 #endif
  57         struct ucounts          *ucounts;
  58         int ucount_max[UCOUNT_COUNTS];
  59 };
  60
  61 struct ucounts {
  62         struct hlist_node node;
  63         struct user_namespace *ns;
  64         kuid_t uid;
  65         atomic_t count;
  66         atomic_t ucount[UCOUNT_COUNTS];
  67 };
  68
  69 extern struct user_namespace init_user_ns;
  70
  71 bool setup_userns_sysctls(struct user_namespace *ns);
  72 void retire_userns_sysctls(struct user_namespace *ns);
  73 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
  74 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
  75
  76 #ifdef CONFIG_USER_NS
  77
  78 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  79 {
  80         if (ns)
  81                 atomic_inc(&ns->count);
  82         return ns;
  83 }
  84
  85 extern int create_user_ns(struct cred *new);
  86 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  87 extern void __put_user_ns(struct user_namespace *ns);
  88
  89 static inline void put_user_ns(struct user_namespace *ns)
  90 {
  91         if (ns && atomic_dec_and_test(&ns->count))
  92                 __put_user_ns(ns);
  93 }
  94
  95 struct seq_operations;
  96 extern const struct seq_operations proc_uid_seq_operations;
  97 extern const struct seq_operations proc_gid_seq_operations;
  98 extern const struct seq_operations proc_projid_seq_operations;
  99 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
 100 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
 101 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
 102 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 103 extern int proc_setgroups_show(struct seq_file *m, void *v);
 104 extern bool userns_may_setgroups(const struct user_namespace *ns);
 105 extern bool current_in_userns(const struct user_namespace *target_ns);
 106 #else
 107
 108 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 109 {
 110         return &init_user_ns;
 111 }
 112
 113 static inline int create_user_ns(struct cred *new)
 114 {
 115         return -EINVAL;
 116 }
 117
 118 static inline int unshare_userns(unsigned long unshare_flags,
 119                                  struct cred **new_cred)
 120 {
 121         if (unshare_flags & CLONE_NEWUSER)
 122                 return -EINVAL;
 123         return 0;
 124 }
 125
 126 static inline void put_user_ns(struct user_namespace *ns)
 127 {
 128 }
 129
 130 static inline bool userns_may_setgroups(const struct user_namespace *ns)
 131 {
 132         return true;
 133 }
 134
 135 static inline bool current_in_userns(const struct user_namespace *target_ns)
 136 {
 137         return true;
 138 }
 139 #endif
 140
 141 #endif /* _LINUX_USER_H */