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_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         /* Register of per-UID persistent keyrings for this namespace */
  68 #ifdef CONFIG_PERSISTENT_KEYRINGS
  69         struct key              *persistent_keyring_register;
  70         struct rw_semaphore     persistent_keyring_register_sem;
  71 #endif
  72         struct work_struct      work;
  73 #ifdef CONFIG_SYSCTL
  74         struct ctl_table_set    set;
  75         struct ctl_table_header *sysctls;
  76 #endif
  77         struct ucounts          *ucounts;
  78         int ucount_max[UCOUNT_COUNTS];
  79 } __randomize_layout;
  80
  81 struct ucounts {
  82         struct hlist_node node;
  83         struct user_namespace *ns;
  84         kuid_t uid;
  85         int count;
  86         atomic_t ucount[UCOUNT_COUNTS];
  87 };
  88
  89 extern struct user_namespace init_user_ns;
  90
  91 bool setup_userns_sysctls(struct user_namespace *ns);
  92 void retire_userns_sysctls(struct user_namespace *ns);
  93 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
  94 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
  95
  96 #ifdef CONFIG_USER_NS
  97
  98 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  99 {
 100         if (ns)
 101                 atomic_inc(&ns->count);
 102         return ns;
 103 }
 104
 105 extern int create_user_ns(struct cred *new);
 106 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
 107 extern void __put_user_ns(struct user_namespace *ns);
 108
 109 static inline void put_user_ns(struct user_namespace *ns)
 110 {
 111         if (ns && atomic_dec_and_test(&ns->count))
 112                 __put_user_ns(ns);
 113 }
 114
 115 struct seq_operations;
 116 extern const struct seq_operations proc_uid_seq_operations;
 117 extern const struct seq_operations proc_gid_seq_operations;
 118 extern const struct seq_operations proc_projid_seq_operations;
 119 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
 120 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
 121 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
 122 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 123 extern int proc_setgroups_show(struct seq_file *m, void *v);
 124 extern bool userns_may_setgroups(const struct user_namespace *ns);
 125 extern bool in_userns(const struct user_namespace *ancestor,
 126                        const struct user_namespace *child);
 127 extern bool current_in_userns(const struct user_namespace *target_ns);
 128 struct ns_common *ns_get_owner(struct ns_common *ns);
 129 #else
 130
 131 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 132 {
 133         return &init_user_ns;
 134 }
 135
 136 static inline int create_user_ns(struct cred *new)
 137 {
 138         return -EINVAL;
 139 }
 140
 141 static inline int unshare_userns(unsigned long unshare_flags,
 142                                  struct cred **new_cred)
 143 {
 144         if (unshare_flags & CLONE_NEWUSER)
 145                 return -EINVAL;
 146         return 0;
 147 }
 148
 149 static inline void put_user_ns(struct user_namespace *ns)
 150 {
 151 }
 152
 153 static inline bool userns_may_setgroups(const struct user_namespace *ns)
 154 {
 155         return true;
 156 }
 157
 158 static inline bool in_userns(const struct user_namespace *ancestor,
 159                              const struct user_namespace *child)
 160 {
 161         return true;
 162 }
 163
 164 static inline bool current_in_userns(const struct user_namespace *target_ns)
 165 {
 166         return true;
 167 }
 168
 169 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
 170 {
 171         return ERR_PTR(-EPERM);
 172 }
 173 #endif
 174
 175 #endif /* _LINUX_USER_H */