LXR linux/include/linux/user

   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
  12struct 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
  25struct ucounts;
  26
  27enum 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
  38struct 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
  64struct 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
  72extern struct user_namespace init_user_ns;
  73
  74bool setup_userns_sysctls(struct user_namespace *ns);
  75void retire_userns_sysctls(struct user_namespace *ns);
  76struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
  77void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
  78
  79#ifdef CONFIG_USER_NS
  80
  81static 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
  88extern int create_user_ns(struct cred *new);
  89extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  90extern void __put_user_ns(struct user_namespace *ns);
  91
  92static 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
  98struct seq_operations;
  99extern const struct seq_operations proc_uid_seq_operations;
 100extern const struct seq_operations proc_gid_seq_operations;
 101extern const struct seq_operations proc_projid_seq_operations;
 102extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
 103extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
 104extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
 105extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 106extern int proc_setgroups_show(struct seq_file *m, void *v);
 107extern bool userns_may_setgroups(const struct user_namespace *ns);
 108extern bool current_in_userns(const struct user_namespace *target_ns);
 109
 110struct ns_common *ns_get_owner(struct ns_common *ns);
 111#else
 112
 113static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 114{
 115        return &init_user_ns;
 116}
 117
 118static inline int create_user_ns(struct cred *new)
 119{
 120        return -EINVAL;
 121}
 122
 123static 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
 131static inline void put_user_ns(struct user_namespace *ns)
 132{
 133}
 134
 135static inline bool userns_may_setgroups(const struct user_namespace *ns)
 136{
 137        return true;
 138}
 139
 140static inline bool current_in_userns(const struct user_namespace *target_ns)
 141{
 142        return true;
 143}
 144
 145static 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 */
 152