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de399236e2
Since the semantics of maximum rlimit values are different, it would be better not to mix ucount and rlimit values. This will prevent the error of using inc_count/dec_ucount for rlimit parameters. This patch also renames the functions to emphasize the lack of connection between rlimit and ucount. v3: - Fix BUG:KASAN:use-after-free_in_dec_ucount. v2: - Fix the array-index-out-of-bounds that was found by the lkp project. Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Alexey Gladkov <legion@kernel.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Link: https://lkml.kernel.org/r/20220518171730.l65lmnnjtnxnftpq@example.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
228 lines
6.2 KiB
C
228 lines
6.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_USER_NAMESPACE_H
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#define _LINUX_USER_NAMESPACE_H
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#include <linux/kref.h>
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#include <linux/nsproxy.h>
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#include <linux/ns_common.h>
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#include <linux/sched.h>
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#include <linux/workqueue.h>
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#include <linux/rwsem.h>
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#include <linux/sysctl.h>
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#include <linux/err.h>
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#define UID_GID_MAP_MAX_BASE_EXTENTS 5
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#define UID_GID_MAP_MAX_EXTENTS 340
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struct uid_gid_extent {
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u32 first;
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u32 lower_first;
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u32 count;
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};
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struct uid_gid_map { /* 64 bytes -- 1 cache line */
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u32 nr_extents;
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union {
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struct uid_gid_extent extent[UID_GID_MAP_MAX_BASE_EXTENTS];
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struct {
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struct uid_gid_extent *forward;
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struct uid_gid_extent *reverse;
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};
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};
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};
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#define USERNS_SETGROUPS_ALLOWED 1UL
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#define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
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struct ucounts;
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enum ucount_type {
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UCOUNT_USER_NAMESPACES,
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UCOUNT_PID_NAMESPACES,
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UCOUNT_UTS_NAMESPACES,
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UCOUNT_IPC_NAMESPACES,
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UCOUNT_NET_NAMESPACES,
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UCOUNT_MNT_NAMESPACES,
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UCOUNT_CGROUP_NAMESPACES,
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UCOUNT_TIME_NAMESPACES,
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#ifdef CONFIG_INOTIFY_USER
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UCOUNT_INOTIFY_INSTANCES,
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UCOUNT_INOTIFY_WATCHES,
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#endif
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#ifdef CONFIG_FANOTIFY
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UCOUNT_FANOTIFY_GROUPS,
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UCOUNT_FANOTIFY_MARKS,
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#endif
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UCOUNT_COUNTS,
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};
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enum rlimit_type {
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UCOUNT_RLIMIT_NPROC,
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UCOUNT_RLIMIT_MSGQUEUE,
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UCOUNT_RLIMIT_SIGPENDING,
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UCOUNT_RLIMIT_MEMLOCK,
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UCOUNT_RLIMIT_COUNTS,
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};
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struct user_namespace {
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struct uid_gid_map uid_map;
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struct uid_gid_map gid_map;
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struct uid_gid_map projid_map;
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struct user_namespace *parent;
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int level;
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kuid_t owner;
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kgid_t group;
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struct ns_common ns;
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unsigned long flags;
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/* parent_could_setfcap: true if the creator if this ns had CAP_SETFCAP
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* in its effective capability set at the child ns creation time. */
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bool parent_could_setfcap;
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#ifdef CONFIG_KEYS
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/* List of joinable keyrings in this namespace. Modification access of
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* these pointers is controlled by keyring_sem. Once
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* user_keyring_register is set, it won't be changed, so it can be
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* accessed directly with READ_ONCE().
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*/
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struct list_head keyring_name_list;
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struct key *user_keyring_register;
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struct rw_semaphore keyring_sem;
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#endif
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/* Register of per-UID persistent keyrings for this namespace */
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#ifdef CONFIG_PERSISTENT_KEYRINGS
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struct key *persistent_keyring_register;
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#endif
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struct work_struct work;
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#ifdef CONFIG_SYSCTL
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struct ctl_table_set set;
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struct ctl_table_header *sysctls;
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#endif
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struct ucounts *ucounts;
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long ucount_max[UCOUNT_COUNTS];
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long rlimit_max[UCOUNT_RLIMIT_COUNTS];
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} __randomize_layout;
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struct ucounts {
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struct hlist_node node;
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struct user_namespace *ns;
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kuid_t uid;
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atomic_t count;
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atomic_long_t ucount[UCOUNT_COUNTS];
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atomic_long_t rlimit[UCOUNT_RLIMIT_COUNTS];
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};
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extern struct user_namespace init_user_ns;
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extern struct ucounts init_ucounts;
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bool setup_userns_sysctls(struct user_namespace *ns);
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void retire_userns_sysctls(struct user_namespace *ns);
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struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
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void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
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struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid);
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struct ucounts * __must_check get_ucounts(struct ucounts *ucounts);
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void put_ucounts(struct ucounts *ucounts);
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static inline long get_rlimit_value(struct ucounts *ucounts, enum rlimit_type type)
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{
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return atomic_long_read(&ucounts->rlimit[type]);
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}
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long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
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bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
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long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type);
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void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type);
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bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long max);
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static inline long get_userns_rlimit_max(struct user_namespace *ns, enum rlimit_type type)
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{
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return READ_ONCE(ns->rlimit_max[type]);
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}
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static inline void set_userns_rlimit_max(struct user_namespace *ns,
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enum rlimit_type type, unsigned long max)
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{
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ns->rlimit_max[type] = max <= LONG_MAX ? max : LONG_MAX;
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}
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#ifdef CONFIG_USER_NS
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static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
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{
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if (ns)
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refcount_inc(&ns->ns.count);
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return ns;
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}
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extern int create_user_ns(struct cred *new);
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extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
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extern void __put_user_ns(struct user_namespace *ns);
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static inline void put_user_ns(struct user_namespace *ns)
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{
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if (ns && refcount_dec_and_test(&ns->ns.count))
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__put_user_ns(ns);
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}
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struct seq_operations;
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extern const struct seq_operations proc_uid_seq_operations;
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extern const struct seq_operations proc_gid_seq_operations;
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extern const struct seq_operations proc_projid_seq_operations;
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extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
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extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
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extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
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extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
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extern int proc_setgroups_show(struct seq_file *m, void *v);
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extern bool userns_may_setgroups(const struct user_namespace *ns);
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extern bool in_userns(const struct user_namespace *ancestor,
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const struct user_namespace *child);
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extern bool current_in_userns(const struct user_namespace *target_ns);
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struct ns_common *ns_get_owner(struct ns_common *ns);
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#else
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static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
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{
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return &init_user_ns;
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}
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static inline int create_user_ns(struct cred *new)
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{
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return -EINVAL;
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}
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static inline int unshare_userns(unsigned long unshare_flags,
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struct cred **new_cred)
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{
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if (unshare_flags & CLONE_NEWUSER)
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return -EINVAL;
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return 0;
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}
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static inline void put_user_ns(struct user_namespace *ns)
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{
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}
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static inline bool userns_may_setgroups(const struct user_namespace *ns)
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{
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return true;
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}
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static inline bool in_userns(const struct user_namespace *ancestor,
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const struct user_namespace *child)
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{
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return true;
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}
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static inline bool current_in_userns(const struct user_namespace *target_ns)
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{
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return true;
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}
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static inline struct ns_common *ns_get_owner(struct ns_common *ns)
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{
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return ERR_PTR(-EPERM);
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}
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#endif
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#endif /* _LINUX_USER_H */
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