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/workqueue.h>
   9 #include <linux/rwsem.h>
  10 #include <linux/sysctl.h>
  11 #include <linux/err.h>
  12
  13 #define UID_GID_MAP_MAX_EXTENTS 5
  14
  15 struct uid_gid_map {    /* 64 bytes -- 1 cache line */
  16         u32 nr_extents;
  17         struct uid_gid_extent {
  18                 u32 first;
  19                 u32 lower_first;
  20                 u32 count;
  21         } extent[UID_GID_MAP_MAX_EXTENTS];
  22 };
  23
  24 #define USERNS_SETGROUPS_ALLOWED 1UL
  25
  26 #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
  27
  28 struct ucounts;
  29
  30 enum ucount_type {
  31         UCOUNT_USER_NAMESPACES,
  32         UCOUNT_PID_NAMESPACES,
  33         UCOUNT_UTS_NAMESPACES,
  34         UCOUNT_IPC_NAMESPACES,
  35         UCOUNT_NET_NAMESPACES,
  36         UCOUNT_MNT_NAMESPACES,
  37         UCOUNT_CGROUP_NAMESPACES,
  38 #ifdef CONFIG_INOTIFY_USER
  39         UCOUNT_INOTIFY_INSTANCES,
  40         UCOUNT_INOTIFY_WATCHES,
  41 #endif
  42         UCOUNT_COUNTS,
  43 };
  44
  45 struct user_namespace {
  46         struct uid_gid_map      uid_map;
  47         struct uid_gid_map      gid_map;
  48         struct uid_gid_map      projid_map;
  49         atomic_t                count;
  50         struct user_namespace   *parent;
  51         int                     level;
  52         kuid_t                  owner;
  53         kgid_t                  group;
  54         struct ns_common        ns;
  55         unsigned long           flags;
  56
  57         /* Register of per-UID persistent keyrings for this namespace */
  58 #ifdef CONFIG_PERSISTENT_KEYRINGS
  59         struct key              *persistent_keyring_register;
  60         struct rw_semaphore     persistent_keyring_register_sem;
  61 #endif
  62         struct work_struct      work;
  63 #ifdef CONFIG_SYSCTL
  64         struct ctl_table_set    set;
  65         struct ctl_table_header *sysctls;
  66 #endif
  67         struct ucounts          *ucounts;
  68         int ucount_max[UCOUNT_COUNTS];
  69 };
  70
  71 struct ucounts {
  72         struct hlist_node node;
  73         struct user_namespace *ns;
  74         kuid_t uid;
  75         int count;
  76         atomic_t ucount[UCOUNT_COUNTS];
  77 };
  78
  79 extern struct user_namespace init_user_ns;
  80
  81 bool setup_userns_sysctls(struct user_namespace *ns);
  82 void retire_userns_sysctls(struct user_namespace *ns);
  83 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
  84 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
  85
  86 #ifdef CONFIG_USER_NS
  87
  88 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  89 {
  90         if (ns)
  91                 atomic_inc(&ns->count);
  92         return ns;
  93 }
  94
  95 extern int create_user_ns(struct cred *new);
  96 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  97 extern void __put_user_ns(struct user_namespace *ns);
  98
  99 static inline void put_user_ns(struct user_namespace *ns)
 100 {
 101         if (ns && atomic_dec_and_test(&ns->count))
 102                 __put_user_ns(ns);
 103 }
 104
 105 struct seq_operations;
 106 extern const struct seq_operations proc_uid_seq_operations;
 107 extern const struct seq_operations proc_gid_seq_operations;
 108 extern const struct seq_operations proc_projid_seq_operations;
 109 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
 110 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
 111 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
 112 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 113 extern int proc_setgroups_show(struct seq_file *m, void *v);
 114 extern bool userns_may_setgroups(const struct user_namespace *ns);
 115 extern bool current_in_userns(const struct user_namespace *target_ns);
 116
 117 struct ns_common *ns_get_owner(struct ns_common *ns);
 118 #else
 119
 120 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 121 {
 122         return &init_user_ns;
 123 }
 124
 125 static inline int create_user_ns(struct cred *new)
 126 {
 127         return -EINVAL;
 128 }
 129
 130 static inline int unshare_userns(unsigned long unshare_flags,
 131                                  struct cred **new_cred)
 132 {
 133         if (unshare_flags & CLONE_NEWUSER)
 134                 return -EINVAL;
 135         return 0;
 136 }
 137
 138 static inline void put_user_ns(struct user_namespace *ns)
 139 {
 140 }
 141
 142 static inline bool userns_may_setgroups(const struct user_namespace *ns)
 143 {
 144         return true;
 145 }
 146
 147 static inline bool current_in_userns(const struct user_namespace *target_ns)
 148 {
 149         return true;
 150 }
 151
 152 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
 153 {
 154         return ERR_PTR(-EPERM);
 155 }
 156 #endif
 157
 158 #endif /* _LINUX_USER_H */