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         UCOUNT_TIME_NAMESPACES,
  49 #ifdef CONFIG_INOTIFY_USER
  50         UCOUNT_INOTIFY_INSTANCES,
  51         UCOUNT_INOTIFY_WATCHES,
  52 #endif
  53 #ifdef CONFIG_FANOTIFY
  54         UCOUNT_FANOTIFY_GROUPS,
  55         UCOUNT_FANOTIFY_MARKS,
  56 #endif
  57         UCOUNT_RLIMIT_NPROC,
  58         UCOUNT_RLIMIT_MSGQUEUE,
  59         UCOUNT_RLIMIT_SIGPENDING,
  60         UCOUNT_RLIMIT_MEMLOCK,
  61         UCOUNT_COUNTS,
  62 };
  63
  64 #define MAX_PER_NAMESPACE_UCOUNTS UCOUNT_RLIMIT_NPROC
  65
  66 struct user_namespace {
  67         struct uid_gid_map      uid_map;
  68         struct uid_gid_map      gid_map;
  69         struct uid_gid_map      projid_map;
  70         struct user_namespace   *parent;
  71         int                     level;
  72         kuid_t                  owner;
  73         kgid_t                  group;
  74         struct ns_common        ns;
  75         unsigned long           flags;
  76         /* parent_could_setfcap: true if the creator if this ns had CAP_SETFCAP
  77          * in its effective capability set at the child ns creation time. */
  78         bool                    parent_could_setfcap;
  79
  80 #ifdef CONFIG_KEYS
  81         /* List of joinable keyrings in this namespace.  Modification access of
  82          * these pointers is controlled by keyring_sem.  Once
  83          * user_keyring_register is set, it won't be changed, so it can be
  84          * accessed directly with READ_ONCE().
  85          */
  86         struct list_head        keyring_name_list;
  87         struct key              *user_keyring_register;
  88         struct rw_semaphore     keyring_sem;
  89 #endif
  90
  91         /* Register of per-UID persistent keyrings for this namespace */
  92 #ifdef CONFIG_PERSISTENT_KEYRINGS
  93         struct key              *persistent_keyring_register;
  94 #endif
  95         struct work_struct      work;
  96 #ifdef CONFIG_SYSCTL
  97         struct ctl_table_set    set;
  98         struct ctl_table_header *sysctls;
  99 #endif
 100         struct ucounts          *ucounts;
 101         long ucount_max[UCOUNT_COUNTS];
 102 } __randomize_layout;
 103
 104 struct ucounts {
 105         struct hlist_node node;
 106         struct user_namespace *ns;
 107         kuid_t uid;
 108         atomic_t count;
 109         atomic_long_t ucount[UCOUNT_COUNTS];
 110 };
 111
 112 extern struct user_namespace init_user_ns;
 113 extern struct ucounts init_ucounts;
 114
 115 bool setup_userns_sysctls(struct user_namespace *ns);
 116 void retire_userns_sysctls(struct user_namespace *ns);
 117 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
 118 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
 119 struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid);
 120 struct ucounts * __must_check get_ucounts(struct ucounts *ucounts);
 121 void put_ucounts(struct ucounts *ucounts);
 122
 123 static inline long get_ucounts_value(struct ucounts *ucounts, enum ucount_type type)
 124 {
 125         return atomic_long_read(&ucounts->ucount[type]);
 126 }
 127
 128 long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v);
 129 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v);
 130 bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsigned long max);
 131
 132 static inline void set_rlimit_ucount_max(struct user_namespace *ns,
 133                 enum ucount_type type, unsigned long max)
 134 {
 135         ns->ucount_max[type] = max <= LONG_MAX ? max : LONG_MAX;
 136 }
 137
 138 #ifdef CONFIG_USER_NS
 139
 140 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 141 {
 142         if (ns)
 143                 refcount_inc(&ns->ns.count);
 144         return ns;
 145 }
 146
 147 extern int create_user_ns(struct cred *new);
 148 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
 149 extern void __put_user_ns(struct user_namespace *ns);
 150
 151 static inline void put_user_ns(struct user_namespace *ns)
 152 {
 153         if (ns && refcount_dec_and_test(&ns->ns.count))
 154                 __put_user_ns(ns);
 155 }
 156
 157 struct seq_operations;
 158 extern const struct seq_operations proc_uid_seq_operations;
 159 extern const struct seq_operations proc_gid_seq_operations;
 160 extern const struct seq_operations proc_projid_seq_operations;
 161 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
 162 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
 163 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
 164 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 165 extern int proc_setgroups_show(struct seq_file *m, void *v);
 166 extern bool userns_may_setgroups(const struct user_namespace *ns);
 167 extern bool in_userns(const struct user_namespace *ancestor,
 168                        const struct user_namespace *child);
 169 extern bool current_in_userns(const struct user_namespace *target_ns);
 170 struct ns_common *ns_get_owner(struct ns_common *ns);
 171 #else
 172
 173 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 174 {
 175         return &init_user_ns;
 176 }
 177
 178 static inline int create_user_ns(struct cred *new)
 179 {
 180         return -EINVAL;
 181 }
 182
 183 static inline int unshare_userns(unsigned long unshare_flags,
 184                                  struct cred **new_cred)
 185 {
 186         if (unshare_flags & CLONE_NEWUSER)
 187                 return -EINVAL;
 188         return 0;
 189 }
 190
 191 static inline void put_user_ns(struct user_namespace *ns)
 192 {
 193 }
 194
 195 static inline bool userns_may_setgroups(const struct user_namespace *ns)
 196 {
 197         return true;
 198 }
 199
 200 static inline bool in_userns(const struct user_namespace *ancestor,
 201                              const struct user_namespace *child)
 202 {
 203         return true;
 204 }
 205
 206 static inline bool current_in_userns(const struct user_namespace *target_ns)
 207 {
 208         return true;
 209 }
 210
 211 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
 212 {
 213         return ERR_PTR(-EPERM);
 214 }
 215 #endif
 216
 217 #endif /* _LINUX_USER_H */