root/include/linux/user_namespace.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. get_user_ns
  2. put_user_ns
  3. get_user_ns
  4. create_user_ns
  5. unshare_userns
  6. put_user_ns
  7. userns_may_setgroups
  8. in_userns
  9. current_in_userns
  10. ns_get_owner

   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_BASE_EXTENTS 5
  15 #define UID_GID_MAP_MAX_EXTENTS 340
  16 
  17 struct uid_gid_extent {
  18         u32 first;
  19         u32 lower_first;
  20         u32 count;
  21 };
  22 
  23 struct uid_gid_map { /* 64 bytes -- 1 cache line */
  24         u32 nr_extents;
  25         union {
  26                 struct uid_gid_extent extent[UID_GID_MAP_MAX_BASE_EXTENTS];
  27                 struct {
  28                         struct uid_gid_extent *forward;
  29                         struct uid_gid_extent *reverse;
  30                 };
  31         };
  32 };
  33 
  34 #define USERNS_SETGROUPS_ALLOWED 1UL
  35 
  36 #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
  37 
  38 struct ucounts;
  39 
  40 enum ucount_type {
  41         UCOUNT_USER_NAMESPACES,
  42         UCOUNT_PID_NAMESPACES,
  43         UCOUNT_UTS_NAMESPACES,
  44         UCOUNT_IPC_NAMESPACES,
  45         UCOUNT_NET_NAMESPACES,
  46         UCOUNT_MNT_NAMESPACES,
  47         UCOUNT_CGROUP_NAMESPACES,
  48 #ifdef CONFIG_INOTIFY_USER
  49         UCOUNT_INOTIFY_INSTANCES,
  50         UCOUNT_INOTIFY_WATCHES,
  51 #endif
  52         UCOUNT_COUNTS,
  53 };
  54 
  55 struct user_namespace {
  56         struct uid_gid_map      uid_map;
  57         struct uid_gid_map      gid_map;
  58         struct uid_gid_map      projid_map;
  59         atomic_t                count;
  60         struct user_namespace   *parent;
  61         int                     level;
  62         kuid_t                  owner;
  63         kgid_t                  group;
  64         struct ns_common        ns;
  65         unsigned long           flags;
  66 
  67 #ifdef CONFIG_KEYS
  68         /* List of joinable keyrings in this namespace.  Modification access of
  69          * these pointers is controlled by keyring_sem.  Once
  70          * user_keyring_register is set, it won't be changed, so it can be
  71          * accessed directly with READ_ONCE().
  72          */
  73         struct list_head        keyring_name_list;
  74         struct key              *user_keyring_register;
  75         struct rw_semaphore     keyring_sem;
  76 #endif
  77 
  78         /* Register of per-UID persistent keyrings for this namespace */
  79 #ifdef CONFIG_PERSISTENT_KEYRINGS
  80         struct key              *persistent_keyring_register;
  81 #endif
  82         struct work_struct      work;
  83 #ifdef CONFIG_SYSCTL
  84         struct ctl_table_set    set;
  85         struct ctl_table_header *sysctls;
  86 #endif
  87         struct ucounts          *ucounts;
  88         int ucount_max[UCOUNT_COUNTS];
  89 } __randomize_layout;
  90 
  91 struct ucounts {
  92         struct hlist_node node;
  93         struct user_namespace *ns;
  94         kuid_t uid;
  95         int count;
  96         atomic_t ucount[UCOUNT_COUNTS];
  97 };
  98 
  99 extern struct user_namespace init_user_ns;
 100 
 101 bool setup_userns_sysctls(struct user_namespace *ns);
 102 void retire_userns_sysctls(struct user_namespace *ns);
 103 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
 104 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
 105 
 106 #ifdef CONFIG_USER_NS
 107 
 108 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 109 {
 110         if (ns)
 111                 atomic_inc(&ns->count);
 112         return ns;
 113 }
 114 
 115 extern int create_user_ns(struct cred *new);
 116 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
 117 extern void __put_user_ns(struct user_namespace *ns);
 118 
 119 static inline void put_user_ns(struct user_namespace *ns)
 120 {
 121         if (ns && atomic_dec_and_test(&ns->count))
 122                 __put_user_ns(ns);
 123 }
 124 
 125 struct seq_operations;
 126 extern const struct seq_operations proc_uid_seq_operations;
 127 extern const struct seq_operations proc_gid_seq_operations;
 128 extern const struct seq_operations proc_projid_seq_operations;
 129 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
 130 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
 131 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
 132 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 133 extern int proc_setgroups_show(struct seq_file *m, void *v);
 134 extern bool userns_may_setgroups(const struct user_namespace *ns);
 135 extern bool in_userns(const struct user_namespace *ancestor,
 136                        const struct user_namespace *child);
 137 extern bool current_in_userns(const struct user_namespace *target_ns);
 138 struct ns_common *ns_get_owner(struct ns_common *ns);
 139 #else
 140 
 141 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 142 {
 143         return &init_user_ns;
 144 }
 145 
 146 static inline int create_user_ns(struct cred *new)
 147 {
 148         return -EINVAL;
 149 }
 150 
 151 static inline int unshare_userns(unsigned long unshare_flags,
 152                                  struct cred **new_cred)
 153 {
 154         if (unshare_flags & CLONE_NEWUSER)
 155                 return -EINVAL;
 156         return 0;
 157 }
 158 
 159 static inline void put_user_ns(struct user_namespace *ns)
 160 {
 161 }
 162 
 163 static inline bool userns_may_setgroups(const struct user_namespace *ns)
 164 {
 165         return true;
 166 }
 167 
 168 static inline bool in_userns(const struct user_namespace *ancestor,
 169                              const struct user_namespace *child)
 170 {
 171         return true;
 172 }
 173 
 174 static inline bool current_in_userns(const struct user_namespace *target_ns)
 175 {
 176         return true;
 177 }
 178 
 179 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
 180 {
 181         return ERR_PTR(-EPERM);
 182 }
 183 #endif
 184 
 185 #endif /* _LINUX_USER_H */

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