LXR linux/include/linux/user

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_USER_NAMESPACE_H
   3#define _LINUX_USER_NAMESPACE_H
   4
   5#include <linux/kref.h>
   6#include <linux/nsproxy.h>
   7#include <linux/ns_common.h>
   8#include <linux/sched.h>
   9#include <linux/workqueue.h>
  10#include <linux/rwsem.h>
  11#include <linux/sysctl.h>
  12#include <linux/err.h>
  13
  14#define UID_GID_MAP_MAX_EXTENTS 5
  15
  16struct uid_gid_map {    /* 64 bytes -- 1 cache line */
  17        u32 nr_extents;
  18        struct uid_gid_extent {
  19                u32 first;
  20                u32 lower_first;
  21                u32 count;
  22        } extent[UID_GID_MAP_MAX_EXTENTS];
  23};
  24
  25#define USERNS_SETGROUPS_ALLOWED 1UL
  26
  27#define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
  28
  29struct ucounts;
  30
  31enum ucount_type {
  32        UCOUNT_USER_NAMESPACES,
  33        UCOUNT_PID_NAMESPACES,
  34        UCOUNT_UTS_NAMESPACES,
  35        UCOUNT_IPC_NAMESPACES,
  36        UCOUNT_NET_NAMESPACES,
  37        UCOUNT_MNT_NAMESPACES,
  38        UCOUNT_CGROUP_NAMESPACES,
  39#ifdef CONFIG_INOTIFY_USER
  40        UCOUNT_INOTIFY_INSTANCES,
  41        UCOUNT_INOTIFY_WATCHES,
  42#endif
  43        UCOUNT_COUNTS,
  44};
  45
  46struct user_namespace {
  47        struct uid_gid_map      uid_map;
  48        struct uid_gid_map      gid_map;
  49        struct uid_gid_map      projid_map;
  50        atomic_t                count;
  51        struct user_namespace   *parent;
  52        int                     level;
  53        kuid_t                  owner;
  54        kgid_t                  group;
  55        struct ns_common        ns;
  56        unsigned long           flags;
  57
  58        /* Register of per-UID persistent keyrings for this namespace */
  59#ifdef CONFIG_PERSISTENT_KEYRINGS
  60        struct key              *persistent_keyring_register;
  61        struct rw_semaphore     persistent_keyring_register_sem;
  62#endif
  63        struct work_struct      work;
  64#ifdef CONFIG_SYSCTL
  65        struct ctl_table_set    set;
  66        struct ctl_table_header *sysctls;
  67#endif
  68        struct ucounts          *ucounts;
  69        int ucount_max[UCOUNT_COUNTS];
  70} __randomize_layout;
  71
  72struct ucounts {
  73        struct hlist_node node;
  74        struct user_namespace *ns;
  75        kuid_t uid;
  76        int count;
  77        atomic_t ucount[UCOUNT_COUNTS];
  78};
  79
  80extern struct user_namespace init_user_ns;
  81
  82bool setup_userns_sysctls(struct user_namespace *ns);
  83void retire_userns_sysctls(struct user_namespace *ns);
  84struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
  85void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
  86
  87#ifdef CONFIG_USER_NS
  88
  89static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  90{
  91        if (ns)
  92                atomic_inc(&ns->count);
  93        return ns;
  94}
  95
  96extern int create_user_ns(struct cred *new);
  97extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  98extern void __put_user_ns(struct user_namespace *ns);
  99
 100static inline void put_user_ns(struct user_namespace *ns)
 101{
 102        if (ns && atomic_dec_and_test(&ns->count))
 103                __put_user_ns(ns);
 104}
 105
 106struct seq_operations;
 107extern const struct seq_operations proc_uid_seq_operations;
 108extern const struct seq_operations proc_gid_seq_operations;
 109extern const struct seq_operations proc_projid_seq_operations;
 110extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
 111extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
 112extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
 113extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 114extern int proc_setgroups_show(struct seq_file *m, void *v);
 115extern bool userns_may_setgroups(const struct user_namespace *ns);
 116extern bool in_userns(const struct user_namespace *ancestor,
 117                       const struct user_namespace *child);
 118extern bool current_in_userns(const struct user_namespace *target_ns);
 119struct ns_common *ns_get_owner(struct ns_common *ns);
 120#else
 121
 122static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 123{
 124        return &init_user_ns;
 125}
 126
 127static inline int create_user_ns(struct cred *new)
 128{
 129        return -EINVAL;
 130}
 131
 132static inline int unshare_userns(unsigned long unshare_flags,
 133                                 struct cred **new_cred)
 134{
 135        if (unshare_flags & CLONE_NEWUSER)
 136                return -EINVAL;
 137        return 0;
 138}
 139
 140static inline void put_user_ns(struct user_namespace *ns)
 141{
 142}
 143
 144static inline bool userns_may_setgroups(const struct user_namespace *ns)
 145{
 146        return true;
 147}
 148
 149static inline bool in_userns(const struct user_namespace *ancestor,
 150                             const struct user_namespace *child)
 151{
 152        return true;
 153}
 154
 155static inline bool current_in_userns(const struct user_namespace *target_ns)
 156{
 157        return true;
 158}
 159
 160static inline struct ns_common *ns_get_owner(struct ns_common *ns)
 161{
 162        return ERR_PTR(-EPERM);
 163}
 164#endif
 165
 166#endif /* _LINUX_USER_H */
 167