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_NET_NAMESPACES,
  33         UCOUNT_MNT_NAMESPACES,
  34         UCOUNT_CGROUP_NAMESPACES,
  35         UCOUNT_COUNTS,
  36 };
  37
  38 struct user_namespace {
  39         struct uid_gid_map      uid_map;
  40         struct uid_gid_map      gid_map;
  41         struct uid_gid_map      projid_map;
  42         atomic_t                count;
  43         struct user_namespace   *parent;
  44         int                     level;
  45         kuid_t                  owner;
  46         kgid_t                  group;
  47         struct ns_common        ns;
  48         unsigned long           flags;
  49
  50         /* Register of per-UID persistent keyrings for this namespace */
  51 #ifdef CONFIG_PERSISTENT_KEYRINGS
  52         struct key              *persistent_keyring_register;
  53         struct rw_semaphore     persistent_keyring_register_sem;
  54 #endif
  55         struct work_struct      work;
  56 #ifdef CONFIG_SYSCTL
  57         struct ctl_table_set    set;
  58         struct ctl_table_header *sysctls;
  59 #endif
  60         struct ucounts          *ucounts;
  61         int ucount_max[UCOUNT_COUNTS];
  62 };
  63
  64 struct ucounts {
  65         struct hlist_node node;
  66         struct user_namespace *ns;
  67         kuid_t uid;
  68         atomic_t count;
  69         atomic_t ucount[UCOUNT_COUNTS];
  70 };
  71
  72 extern struct user_namespace init_user_ns;
  73
  74 bool setup_userns_sysctls(struct user_namespace *ns);
  75 void retire_userns_sysctls(struct user_namespace *ns);
  76 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
  77 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
  78
  79 #ifdef CONFIG_USER_NS
  80
  81 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  82 {
  83         if (ns)
  84                 atomic_inc(&ns->count);
  85         return ns;
  86 }
  87
  88 extern int create_user_ns(struct cred *new);
  89 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  90 extern void __put_user_ns(struct user_namespace *ns);
  91
  92 static inline void put_user_ns(struct user_namespace *ns)
  93 {
  94         if (ns && atomic_dec_and_test(&ns->count))
  95                 __put_user_ns(ns);
  96 }
  97
  98 struct seq_operations;
  99 extern const struct seq_operations proc_uid_seq_operations;
 100 extern const struct seq_operations proc_gid_seq_operations;
 101 extern const struct seq_operations proc_projid_seq_operations;
 102 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
 103 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
 104 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
 105 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 106 extern int proc_setgroups_show(struct seq_file *m, void *v);
 107 extern bool userns_may_setgroups(const struct user_namespace *ns);
 108 extern bool current_in_userns(const struct user_namespace *target_ns);
 109
 110 struct ns_common *ns_get_owner(struct ns_common *ns);
 111 #else
 112
 113 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 114 {
 115         return &init_user_ns;
 116 }
 117
 118 static inline int create_user_ns(struct cred *new)
 119 {
 120         return -EINVAL;
 121 }
 122
 123 static inline int unshare_userns(unsigned long unshare_flags,
 124                                  struct cred **new_cred)
 125 {
 126         if (unshare_flags & CLONE_NEWUSER)
 127                 return -EINVAL;
 128         return 0;
 129 }
 130
 131 static inline void put_user_ns(struct user_namespace *ns)
 132 {
 133 }
 134
 135 static inline bool userns_may_setgroups(const struct user_namespace *ns)
 136 {
 137         return true;
 138 }
 139
 140 static inline bool current_in_userns(const struct user_namespace *target_ns)
 141 {
 142         return true;
 143 }
 144
 145 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
 146 {
 147         return ERR_PTR(-EPERM);
 148 }
 149 #endif
 150
 151 #endif /* _LINUX_USER_H */