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![David Howells](/assets/img/avatar_default.png)
Keyring names are held in a single global list that any process can pick from by means of keyctl_join_session_keyring (provided the keyring grants Search permission). This isn't very container friendly, however. Make the following changes: (1) Make default session, process and thread keyring names begin with a '.' instead of '_'. (2) Keyrings whose names begin with a '.' aren't added to the list. Such keyrings are system specials. (3) Replace the global list with per-user_namespace lists. A keyring adds its name to the list for the user_namespace that it is currently in. (4) When a user_namespace is deleted, it just removes itself from the keyring name list. The global keyring_name_lock is retained for accessing the name lists. This allows (4) to work. This can be tested by: # keyctl newring foo @s 995906392 # unshare -U $ keyctl show ... 995906392 --alswrv 65534 65534 \_ keyring: foo ... $ keyctl session foo Joined session keyring: 935622349 As can be seen, a new session keyring was created. The capability bit KEYCTL_CAPS1_NS_KEYRING_NAME is set if the kernel is employing this feature. Signed-off-by: David Howells <dhowells@redhat.com> cc: Eric W. Biederman <ebiederm@xmission.com>
180 lines
4.5 KiB
C
180 lines
4.5 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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#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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UCOUNT_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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atomic_t count;
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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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#ifdef CONFIG_KEYS
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/* List of joinable keyrings in this namespace */
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struct list_head keyring_name_list;
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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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struct rw_semaphore persistent_keyring_register_sem;
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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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int ucount_max[UCOUNT_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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int count;
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atomic_t ucount[UCOUNT_COUNTS];
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};
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extern struct user_namespace init_user_ns;
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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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#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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atomic_inc(&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 && atomic_dec_and_test(&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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