include/linux/user_namespace.h

   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
  16 struct 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
  29 struct ucounts;
  30
  31 enum 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
  46 struct 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
  72 struct 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
  80 extern struct user_namespace init_user_ns;
  81
  82 bool setup_userns_sysctls(struct user_namespace *ns);
  83 void retire_userns_sysctls(struct user_namespace *ns);
  84 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
  85 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
  86
  87 #ifdef CONFIG_USER_NS
  88
  89 static 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
  96 extern int create_user_ns(struct cred *new);
  97 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  98 extern void __put_user_ns(struct user_namespace *ns);
  99
 100 static 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
 106 struct seq_operations;
 107 extern const struct seq_operations proc_uid_seq_operations;
 108 extern const struct seq_operations proc_gid_seq_operations;
 109 extern const struct seq_operations proc_projid_seq_operations;
 110 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
 111 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
 112 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
 113 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 114 extern int proc_setgroups_show(struct seq_file *m, void *v);
 115 extern bool userns_may_setgroups(const struct user_namespace *ns);
 116 extern bool in_userns(const struct user_namespace *ancestor,
 117                        const struct user_namespace *child);
 118 extern bool current_in_userns(const struct user_namespace *target_ns);
 119 struct ns_common *ns_get_owner(struct ns_common *ns);
 120 #else
 121
 122 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 123 {
 124         return &init_user_ns;
 125 }
 126
 127 static inline int create_user_ns(struct cred *new)
 128 {
 129         return -EINVAL;
 130 }
 131
 132 static 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
 140 static inline void put_user_ns(struct user_namespace *ns)
 141 {
 142 }
 143
 144 static inline bool userns_may_setgroups(const struct user_namespace *ns)
 145 {
 146         return true;
 147 }
 148
 149 static inline bool in_userns(const struct user_namespace *ancestor,
 150                              const struct user_namespace *child)
 151 {
 152         return true;
 153 }
 154
 155 static inline bool current_in_userns(const struct user_namespace *target_ns)
 156 {
 157         return true;
 158 }
 159
 160 static 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 */