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