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kernel/user_namespace.c
27.3 KB
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/* * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation, version 2 of the * License. */ |
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#include <linux/export.h> |
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#include <linux/nsproxy.h> |
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#include <linux/slab.h> |
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#include <linux/user_namespace.h> |
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#include <linux/proc_ns.h> |
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#include <linux/highuid.h> |
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#include <linux/cred.h> |
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#include <linux/securebits.h> |
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#include <linux/keyctl.h> #include <linux/key-type.h> #include <keys/user-type.h> #include <linux/seq_file.h> #include <linux/fs.h> #include <linux/uaccess.h> #include <linux/ctype.h> |
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#include <linux/projid.h> |
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#include <linux/fs_struct.h> |
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|
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static struct kmem_cache *user_ns_cachep __read_mostly; |
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static DEFINE_MUTEX(userns_state_mutex); |
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|
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static bool new_idmap_permitted(const struct file *file, struct user_namespace *ns, int cap_setid, |
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struct uid_gid_map *map); |
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static void free_user_ns(struct work_struct *work); |
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|
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static struct ucounts *inc_user_namespaces(struct user_namespace *ns, kuid_t uid) { return inc_ucount(ns, uid, UCOUNT_USER_NAMESPACES); } static void dec_user_namespaces(struct ucounts *ucounts) { return dec_ucount(ucounts, UCOUNT_USER_NAMESPACES); } |
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static void set_cred_user_ns(struct cred *cred, struct user_namespace *user_ns) { /* Start with the same capabilities as init but useless for doing * anything as the capabilities are bound to the new user namespace. */ cred->securebits = SECUREBITS_DEFAULT; cred->cap_inheritable = CAP_EMPTY_SET; cred->cap_permitted = CAP_FULL_SET; cred->cap_effective = CAP_FULL_SET; |
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cred->cap_ambient = CAP_EMPTY_SET; |
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cred->cap_bset = CAP_FULL_SET; #ifdef CONFIG_KEYS key_put(cred->request_key_auth); cred->request_key_auth = NULL; #endif /* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */ cred->user_ns = user_ns; } |
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/* |
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* Create a new user namespace, deriving the creator from the user in the * passed credentials, and replacing that user with the new root user for the * new namespace. * * This is called by copy_creds(), which will finish setting the target task's * credentials. |
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*/ |
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int create_user_ns(struct cred *new) |
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{ |
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struct user_namespace *ns, *parent_ns = new->user_ns; |
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kuid_t owner = new->euid; kgid_t group = new->egid; |
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struct ucounts *ucounts; |
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int ret, i; |
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|
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ret = -ENOSPC; |
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if (parent_ns->level > 32) |
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goto fail; |
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ucounts = inc_user_namespaces(parent_ns, owner); if (!ucounts) |
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goto fail; |
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|
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/* * Verify that we can not violate the policy of which files * may be accessed that is specified by the root directory, * by verifing that the root directory is at the root of the * mount namespace which allows all files to be accessed. */ |
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ret = -EPERM; |
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if (current_chrooted()) |
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goto fail_dec; |
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|
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/* The creator needs a mapping in the parent user namespace * or else we won't be able to reasonably tell userspace who * created a user_namespace. */ |
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ret = -EPERM; |
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if (!kuid_has_mapping(parent_ns, owner) || !kgid_has_mapping(parent_ns, group)) |
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goto fail_dec; |
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|
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ret = -ENOMEM; |
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ns = kmem_cache_zalloc(user_ns_cachep, GFP_KERNEL); |
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if (!ns) |
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goto fail_dec; |
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|
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ret = ns_alloc_inum(&ns->ns); |
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if (ret) goto fail_free; |
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ns->ns.ops = &userns_operations; |
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|
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atomic_set(&ns->count, 1); |
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/* Leave the new->user_ns reference with the new user namespace. */ |
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ns->parent = parent_ns; |
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ns->level = parent_ns->level + 1; |
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ns->owner = owner; ns->group = group; |
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INIT_WORK(&ns->work, free_user_ns); |
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for (i = 0; i < UCOUNT_COUNTS; i++) { ns->ucount_max[i] = INT_MAX; } |
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ns->ucounts = ucounts; |
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/* Inherit USERNS_SETGROUPS_ALLOWED from our parent */ mutex_lock(&userns_state_mutex); ns->flags = parent_ns->flags; mutex_unlock(&userns_state_mutex); |
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#ifdef CONFIG_PERSISTENT_KEYRINGS init_rwsem(&ns->persistent_keyring_register_sem); #endif |
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ret = -ENOMEM; if (!setup_userns_sysctls(ns)) goto fail_keyring; set_cred_user_ns(new, ns); |
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return 0; |
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fail_keyring: #ifdef CONFIG_PERSISTENT_KEYRINGS key_put(ns->persistent_keyring_register); #endif ns_free_inum(&ns->ns); |
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fail_free: |
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kmem_cache_free(user_ns_cachep, ns); |
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fail_dec: |
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dec_user_namespaces(ucounts); |
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fail: |
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return ret; |
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} |
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int unshare_userns(unsigned long unshare_flags, struct cred **new_cred) { struct cred *cred; |
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int err = -ENOMEM; |
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if (!(unshare_flags & CLONE_NEWUSER)) return 0; cred = prepare_creds(); |
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if (cred) { err = create_user_ns(cred); if (err) put_cred(cred); else *new_cred = cred; } |
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return err; |
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} |
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static void free_user_ns(struct work_struct *work) |
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{ |
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struct user_namespace *parent, *ns = container_of(work, struct user_namespace, work); |
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do { |
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struct ucounts *ucounts = ns->ucounts; |
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parent = ns->parent; |
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retire_userns_sysctls(ns); |
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#ifdef CONFIG_PERSISTENT_KEYRINGS key_put(ns->persistent_keyring_register); #endif |
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ns_free_inum(&ns->ns); |
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kmem_cache_free(user_ns_cachep, ns); |
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dec_user_namespaces(ucounts); |
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ns = parent; } while (atomic_dec_and_test(&parent->count)); |
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} |
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void __put_user_ns(struct user_namespace *ns) { schedule_work(&ns->work); } EXPORT_SYMBOL(__put_user_ns); |
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static u32 map_id_range_down(struct uid_gid_map *map, u32 id, u32 count) |
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{ |
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unsigned idx, extents; u32 first, last, id2; |
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|
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id2 = id + count - 1; |
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/* Find the matching extent */ extents = map->nr_extents; |
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smp_rmb(); |
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for (idx = 0; idx < extents; idx++) { first = map->extent[idx].first; last = first + map->extent[idx].count - 1; if (id >= first && id <= last && (id2 >= first && id2 <= last)) break; } /* Map the id or note failure */ if (idx < extents) id = (id - first) + map->extent[idx].lower_first; else id = (u32) -1; return id; } static u32 map_id_down(struct uid_gid_map *map, u32 id) { unsigned idx, extents; u32 first, last; /* Find the matching extent */ extents = map->nr_extents; |
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smp_rmb(); |
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for (idx = 0; idx < extents; idx++) { first = map->extent[idx].first; last = first + map->extent[idx].count - 1; if (id >= first && id <= last) break; } /* Map the id or note failure */ if (idx < extents) id = (id - first) + map->extent[idx].lower_first; else id = (u32) -1; return id; } static u32 map_id_up(struct uid_gid_map *map, u32 id) { unsigned idx, extents; u32 first, last; /* Find the matching extent */ extents = map->nr_extents; |
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smp_rmb(); |
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for (idx = 0; idx < extents; idx++) { first = map->extent[idx].lower_first; last = first + map->extent[idx].count - 1; if (id >= first && id <= last) break; |
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} |
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/* Map the id or note failure */ if (idx < extents) id = (id - first) + map->extent[idx].first; else id = (u32) -1; return id; } /** * make_kuid - Map a user-namespace uid pair into a kuid. * @ns: User namespace that the uid is in * @uid: User identifier * * Maps a user-namespace uid pair into a kernel internal kuid, * and returns that kuid. * * When there is no mapping defined for the user-namespace uid * pair INVALID_UID is returned. Callers are expected to test |
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* for and handle INVALID_UID being returned. INVALID_UID |
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* may be tested for using uid_valid(). */ kuid_t make_kuid(struct user_namespace *ns, uid_t uid) { /* Map the uid to a global kernel uid */ return KUIDT_INIT(map_id_down(&ns->uid_map, uid)); } EXPORT_SYMBOL(make_kuid); /** * from_kuid - Create a uid from a kuid user-namespace pair. * @targ: The user namespace we want a uid in. * @kuid: The kernel internal uid to start with. * * Map @kuid into the user-namespace specified by @targ and * return the resulting uid. * * There is always a mapping into the initial user_namespace. * * If @kuid has no mapping in @targ (uid_t)-1 is returned. */ uid_t from_kuid(struct user_namespace *targ, kuid_t kuid) { /* Map the uid from a global kernel uid */ return map_id_up(&targ->uid_map, __kuid_val(kuid)); } EXPORT_SYMBOL(from_kuid); /** * from_kuid_munged - Create a uid from a kuid user-namespace pair. * @targ: The user namespace we want a uid in. * @kuid: The kernel internal uid to start with. * * Map @kuid into the user-namespace specified by @targ and * return the resulting uid. * * There is always a mapping into the initial user_namespace. * * Unlike from_kuid from_kuid_munged never fails and always * returns a valid uid. This makes from_kuid_munged appropriate * for use in syscalls like stat and getuid where failing the * system call and failing to provide a valid uid are not an * options. * * If @kuid has no mapping in @targ overflowuid is returned. */ uid_t from_kuid_munged(struct user_namespace *targ, kuid_t kuid) { uid_t uid; uid = from_kuid(targ, kuid); if (uid == (uid_t) -1) uid = overflowuid; return uid; } EXPORT_SYMBOL(from_kuid_munged); /** * make_kgid - Map a user-namespace gid pair into a kgid. * @ns: User namespace that the gid is in |
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* @gid: group identifier |
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* * Maps a user-namespace gid pair into a kernel internal kgid, * and returns that kgid. * * When there is no mapping defined for the user-namespace gid * pair INVALID_GID is returned. Callers are expected to test * for and handle INVALID_GID being returned. INVALID_GID may be * tested for using gid_valid(). */ kgid_t make_kgid(struct user_namespace *ns, gid_t gid) { /* Map the gid to a global kernel gid */ return KGIDT_INIT(map_id_down(&ns->gid_map, gid)); } EXPORT_SYMBOL(make_kgid); /** * from_kgid - Create a gid from a kgid user-namespace pair. * @targ: The user namespace we want a gid in. * @kgid: The kernel internal gid to start with. * * Map @kgid into the user-namespace specified by @targ and * return the resulting gid. * * There is always a mapping into the initial user_namespace. * * If @kgid has no mapping in @targ (gid_t)-1 is returned. */ gid_t from_kgid(struct user_namespace *targ, kgid_t kgid) { /* Map the gid from a global kernel gid */ return map_id_up(&targ->gid_map, __kgid_val(kgid)); } EXPORT_SYMBOL(from_kgid); /** * from_kgid_munged - Create a gid from a kgid user-namespace pair. * @targ: The user namespace we want a gid in. * @kgid: The kernel internal gid to start with. * * Map @kgid into the user-namespace specified by @targ and * return the resulting gid. * * There is always a mapping into the initial user_namespace. * * Unlike from_kgid from_kgid_munged never fails and always * returns a valid gid. This makes from_kgid_munged appropriate * for use in syscalls like stat and getgid where failing the * system call and failing to provide a valid gid are not options. * * If @kgid has no mapping in @targ overflowgid is returned. */ gid_t from_kgid_munged(struct user_namespace *targ, kgid_t kgid) { gid_t gid; gid = from_kgid(targ, kgid); if (gid == (gid_t) -1) gid = overflowgid; return gid; } EXPORT_SYMBOL(from_kgid_munged); |
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/** * make_kprojid - Map a user-namespace projid pair into a kprojid. * @ns: User namespace that the projid is in * @projid: Project identifier * * Maps a user-namespace uid pair into a kernel internal kuid, * and returns that kuid. * * When there is no mapping defined for the user-namespace projid * pair INVALID_PROJID is returned. Callers are expected to test * for and handle handle INVALID_PROJID being returned. INVALID_PROJID * may be tested for using projid_valid(). */ kprojid_t make_kprojid(struct user_namespace *ns, projid_t projid) { /* Map the uid to a global kernel uid */ return KPROJIDT_INIT(map_id_down(&ns->projid_map, projid)); } EXPORT_SYMBOL(make_kprojid); /** * from_kprojid - Create a projid from a kprojid user-namespace pair. * @targ: The user namespace we want a projid in. * @kprojid: The kernel internal project identifier to start with. * * Map @kprojid into the user-namespace specified by @targ and * return the resulting projid. * * There is always a mapping into the initial user_namespace. * * If @kprojid has no mapping in @targ (projid_t)-1 is returned. */ projid_t from_kprojid(struct user_namespace *targ, kprojid_t kprojid) { /* Map the uid from a global kernel uid */ return map_id_up(&targ->projid_map, __kprojid_val(kprojid)); } EXPORT_SYMBOL(from_kprojid); /** * from_kprojid_munged - Create a projiid from a kprojid user-namespace pair. * @targ: The user namespace we want a projid in. * @kprojid: The kernel internal projid to start with. * * Map @kprojid into the user-namespace specified by @targ and * return the resulting projid. * * There is always a mapping into the initial user_namespace. * * Unlike from_kprojid from_kprojid_munged never fails and always * returns a valid projid. This makes from_kprojid_munged * appropriate for use in syscalls like stat and where * failing the system call and failing to provide a valid projid are * not an options. * * If @kprojid has no mapping in @targ OVERFLOW_PROJID is returned. */ projid_t from_kprojid_munged(struct user_namespace *targ, kprojid_t kprojid) { projid_t projid; projid = from_kprojid(targ, kprojid); if (projid == (projid_t) -1) projid = OVERFLOW_PROJID; return projid; } EXPORT_SYMBOL(from_kprojid_munged); |
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static int uid_m_show(struct seq_file *seq, void *v) { struct user_namespace *ns = seq->private; struct uid_gid_extent *extent = v; struct user_namespace *lower_ns; uid_t lower; |
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lower_ns = seq_user_ns(seq); |
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if ((lower_ns == ns) && lower_ns->parent) lower_ns = lower_ns->parent; lower = from_kuid(lower_ns, KUIDT_INIT(extent->lower_first)); seq_printf(seq, "%10u %10u %10u ", extent->first, lower, extent->count); return 0; |
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} |
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static int gid_m_show(struct seq_file *seq, void *v) |
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{ |
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struct user_namespace *ns = seq->private; struct uid_gid_extent *extent = v; struct user_namespace *lower_ns; gid_t lower; |
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lower_ns = seq_user_ns(seq); |
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if ((lower_ns == ns) && lower_ns->parent) lower_ns = lower_ns->parent; |
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lower = from_kgid(lower_ns, KGIDT_INIT(extent->lower_first)); seq_printf(seq, "%10u %10u %10u ", extent->first, lower, extent->count); return 0; } |
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static int projid_m_show(struct seq_file *seq, void *v) { struct user_namespace *ns = seq->private; struct uid_gid_extent *extent = v; struct user_namespace *lower_ns; projid_t lower; lower_ns = seq_user_ns(seq); if ((lower_ns == ns) && lower_ns->parent) lower_ns = lower_ns->parent; lower = from_kprojid(lower_ns, KPROJIDT_INIT(extent->lower_first)); seq_printf(seq, "%10u %10u %10u ", extent->first, lower, extent->count); return 0; } |
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static void *m_start(struct seq_file *seq, loff_t *ppos, struct uid_gid_map *map) |
22d917d80 userns: Rework th... |
531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 |
{ struct uid_gid_extent *extent = NULL; loff_t pos = *ppos; if (pos < map->nr_extents) extent = &map->extent[pos]; return extent; } static void *uid_m_start(struct seq_file *seq, loff_t *ppos) { struct user_namespace *ns = seq->private; return m_start(seq, ppos, &ns->uid_map); } static void *gid_m_start(struct seq_file *seq, loff_t *ppos) { struct user_namespace *ns = seq->private; return m_start(seq, ppos, &ns->gid_map); } |
f76d207a6 userns: Add kproj... |
554 555 556 557 558 559 |
static void *projid_m_start(struct seq_file *seq, loff_t *ppos) { struct user_namespace *ns = seq->private; return m_start(seq, ppos, &ns->projid_map); } |
22d917d80 userns: Rework th... |
560 561 562 563 564 565 566 567 568 569 |
static void *m_next(struct seq_file *seq, void *v, loff_t *pos) { (*pos)++; return seq->op->start(seq, pos); } static void m_stop(struct seq_file *seq, void *v) { return; } |
ccf94f1b4 proc: constify se... |
570 |
const struct seq_operations proc_uid_seq_operations = { |
22d917d80 userns: Rework th... |
571 572 573 574 575 |
.start = uid_m_start, .stop = m_stop, .next = m_next, .show = uid_m_show, }; |
ccf94f1b4 proc: constify se... |
576 |
const struct seq_operations proc_gid_seq_operations = { |
22d917d80 userns: Rework th... |
577 578 579 580 581 |
.start = gid_m_start, .stop = m_stop, .next = m_next, .show = gid_m_show, }; |
ccf94f1b4 proc: constify se... |
582 |
const struct seq_operations proc_projid_seq_operations = { |
f76d207a6 userns: Add kproj... |
583 584 585 586 587 |
.start = projid_m_start, .stop = m_stop, .next = m_next, .show = projid_m_show, }; |
68a9a435e kernel/user_names... |
588 589 |
static bool mappings_overlap(struct uid_gid_map *new_map, struct uid_gid_extent *extent) |
0bd14b4fd userns: Allow any... |
590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 |
{ u32 upper_first, lower_first, upper_last, lower_last; unsigned idx; upper_first = extent->first; lower_first = extent->lower_first; upper_last = upper_first + extent->count - 1; lower_last = lower_first + extent->count - 1; for (idx = 0; idx < new_map->nr_extents; idx++) { u32 prev_upper_first, prev_lower_first; u32 prev_upper_last, prev_lower_last; struct uid_gid_extent *prev; prev = &new_map->extent[idx]; prev_upper_first = prev->first; prev_lower_first = prev->lower_first; prev_upper_last = prev_upper_first + prev->count - 1; prev_lower_last = prev_lower_first + prev->count - 1; /* Does the upper range intersect a previous extent? */ if ((prev_upper_first <= upper_last) && (prev_upper_last >= upper_first)) return true; /* Does the lower range intersect a previous extent? */ if ((prev_lower_first <= lower_last) && (prev_lower_last >= lower_first)) return true; } return false; } |
22d917d80 userns: Rework th... |
623 624 625 626 627 628 629 630 631 632 |
static ssize_t map_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos, int cap_setid, struct uid_gid_map *map, struct uid_gid_map *parent_map) { struct seq_file *seq = file->private_data; struct user_namespace *ns = seq->private; struct uid_gid_map new_map; unsigned idx; |
0bd14b4fd userns: Allow any... |
633 |
struct uid_gid_extent *extent = NULL; |
70f6cbb6f kernel/*: switch ... |
634 |
char *kbuf = NULL, *pos, *next_line; |
22d917d80 userns: Rework th... |
635 636 637 |
ssize_t ret = -EINVAL; /* |
f0d62aec9 userns: Rename id... |
638 |
* The userns_state_mutex serializes all writes to any given map. |
22d917d80 userns: Rework th... |
639 640 641 642 643 644 645 646 647 648 649 650 651 652 |
* * Any map is only ever written once. * * An id map fits within 1 cache line on most architectures. * * On read nothing needs to be done unless you are on an * architecture with a crazy cache coherency model like alpha. * * There is a one time data dependency between reading the * count of the extents and the values of the extents. The * desired behavior is to see the values of the extents that * were written before the count of the extents. * * To achieve this smp_wmb() is used on guarantee the write |
e79323bd8 user namespace: f... |
653 654 |
* order and smp_rmb() is guaranteed that we don't have crazy * architectures returning stale data. |
22d917d80 userns: Rework th... |
655 |
*/ |
f0d62aec9 userns: Rename id... |
656 |
mutex_lock(&userns_state_mutex); |
22d917d80 userns: Rework th... |
657 658 659 660 661 |
ret = -EPERM; /* Only allow one successful write to the map */ if (map->nr_extents != 0) goto out; |
41c21e351 userns: Changing ... |
662 663 |
/* * Adjusting namespace settings requires capabilities on the target. |
5c1469de7 user_ns: Introduc... |
664 |
*/ |
41c21e351 userns: Changing ... |
665 |
if (cap_valid(cap_setid) && !file_ns_capable(file, ns, CAP_SYS_ADMIN)) |
22d917d80 userns: Rework th... |
666 |
goto out; |
36476beac userns; Correct t... |
667 |
/* Only allow < page size writes at the beginning of the file */ |
22d917d80 userns: Rework th... |
668 669 670 671 672 |
ret = -EINVAL; if ((*ppos != 0) || (count >= PAGE_SIZE)) goto out; /* Slurp in the user data */ |
70f6cbb6f kernel/*: switch ... |
673 674 675 676 |
kbuf = memdup_user_nul(buf, count); if (IS_ERR(kbuf)) { ret = PTR_ERR(kbuf); kbuf = NULL; |
22d917d80 userns: Rework th... |
677 |
goto out; |
70f6cbb6f kernel/*: switch ... |
678 |
} |
22d917d80 userns: Rework th... |
679 680 681 682 683 |
/* Parse the user data */ ret = -EINVAL; pos = kbuf; new_map.nr_extents = 0; |
68a9a435e kernel/user_names... |
684 |
for (; pos; pos = next_line) { |
22d917d80 userns: Rework th... |
685 686 687 688 689 690 691 692 693 694 |
extent = &new_map.extent[new_map.nr_extents]; /* Find the end of line and ensure I don't look past it */ next_line = strchr(pos, ' '); if (next_line) { *next_line = '\0'; next_line++; if (*next_line == '\0') next_line = NULL; |
5c1469de7 user_ns: Introduc... |
695 |
} |
22d917d80 userns: Rework th... |
696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 |
pos = skip_spaces(pos); extent->first = simple_strtoul(pos, &pos, 10); if (!isspace(*pos)) goto out; pos = skip_spaces(pos); extent->lower_first = simple_strtoul(pos, &pos, 10); if (!isspace(*pos)) goto out; pos = skip_spaces(pos); extent->count = simple_strtoul(pos, &pos, 10); if (*pos && !isspace(*pos)) goto out; /* Verify there is not trailing junk on the line */ pos = skip_spaces(pos); if (*pos != '\0') goto out; /* Verify we have been given valid starting values */ if ((extent->first == (u32) -1) || |
68a9a435e kernel/user_names... |
719 |
(extent->lower_first == (u32) -1)) |
22d917d80 userns: Rework th... |
720 |
goto out; |
68a9a435e kernel/user_names... |
721 722 723 |
/* Verify count is not zero and does not cause the * extent to wrap */ |
22d917d80 userns: Rework th... |
724 725 |
if ((extent->first + extent->count) <= extent->first) goto out; |
68a9a435e kernel/user_names... |
726 727 |
if ((extent->lower_first + extent->count) <= extent->lower_first) |
22d917d80 userns: Rework th... |
728 |
goto out; |
0bd14b4fd userns: Allow any... |
729 730 |
/* Do the ranges in extent overlap any previous extents? */ if (mappings_overlap(&new_map, extent)) |
22d917d80 userns: Rework th... |
731 732 733 |
goto out; new_map.nr_extents++; |
22d917d80 userns: Rework th... |
734 735 736 737 738 |
/* Fail if the file contains too many extents */ if ((new_map.nr_extents == UID_GID_MAP_MAX_EXTENTS) && (next_line != NULL)) goto out; |
5c1469de7 user_ns: Introduc... |
739 |
} |
22d917d80 userns: Rework th... |
740 741 742 743 744 745 |
/* Be very certaint the new map actually exists */ if (new_map.nr_extents == 0) goto out; ret = -EPERM; /* Validate the user is allowed to use user id's mapped to. */ |
6708075f1 userns: Don't let... |
746 |
if (!new_idmap_permitted(file, ns, cap_setid, &new_map)) |
22d917d80 userns: Rework th... |
747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 |
goto out; /* Map the lower ids from the parent user namespace to the * kernel global id space. */ for (idx = 0; idx < new_map.nr_extents; idx++) { u32 lower_first; extent = &new_map.extent[idx]; lower_first = map_id_range_down(parent_map, extent->lower_first, extent->count); /* Fail if we can not map the specified extent to * the kernel global id space. */ if (lower_first == (u32) -1) goto out; extent->lower_first = lower_first; } /* Install the map */ memcpy(map->extent, new_map.extent, new_map.nr_extents*sizeof(new_map.extent[0])); smp_wmb(); map->nr_extents = new_map.nr_extents; *ppos = count; ret = count; out: |
f0d62aec9 userns: Rename id... |
778 |
mutex_unlock(&userns_state_mutex); |
70f6cbb6f kernel/*: switch ... |
779 |
kfree(kbuf); |
22d917d80 userns: Rework th... |
780 781 |
return ret; } |
68a9a435e kernel/user_names... |
782 783 |
ssize_t proc_uid_map_write(struct file *file, const char __user *buf, size_t size, loff_t *ppos) |
22d917d80 userns: Rework th... |
784 785 786 |
{ struct seq_file *seq = file->private_data; struct user_namespace *ns = seq->private; |
c450f371d userns: For /proc... |
787 |
struct user_namespace *seq_ns = seq_user_ns(seq); |
22d917d80 userns: Rework th... |
788 789 790 |
if (!ns->parent) return -EPERM; |
c450f371d userns: For /proc... |
791 792 |
if ((seq_ns != ns) && (seq_ns != ns->parent)) return -EPERM; |
22d917d80 userns: Rework th... |
793 794 795 |
return map_write(file, buf, size, ppos, CAP_SETUID, &ns->uid_map, &ns->parent->uid_map); } |
68a9a435e kernel/user_names... |
796 797 |
ssize_t proc_gid_map_write(struct file *file, const char __user *buf, size_t size, loff_t *ppos) |
22d917d80 userns: Rework th... |
798 799 800 |
{ struct seq_file *seq = file->private_data; struct user_namespace *ns = seq->private; |
c450f371d userns: For /proc... |
801 |
struct user_namespace *seq_ns = seq_user_ns(seq); |
22d917d80 userns: Rework th... |
802 803 804 |
if (!ns->parent) return -EPERM; |
c450f371d userns: For /proc... |
805 806 |
if ((seq_ns != ns) && (seq_ns != ns->parent)) return -EPERM; |
22d917d80 userns: Rework th... |
807 808 809 |
return map_write(file, buf, size, ppos, CAP_SETGID, &ns->gid_map, &ns->parent->gid_map); } |
68a9a435e kernel/user_names... |
810 811 |
ssize_t proc_projid_map_write(struct file *file, const char __user *buf, size_t size, loff_t *ppos) |
f76d207a6 userns: Add kproj... |
812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 |
{ struct seq_file *seq = file->private_data; struct user_namespace *ns = seq->private; struct user_namespace *seq_ns = seq_user_ns(seq); if (!ns->parent) return -EPERM; if ((seq_ns != ns) && (seq_ns != ns->parent)) return -EPERM; /* Anyone can set any valid project id no capability needed */ return map_write(file, buf, size, ppos, -1, &ns->projid_map, &ns->parent->projid_map); } |
68a9a435e kernel/user_names... |
827 |
static bool new_idmap_permitted(const struct file *file, |
6708075f1 userns: Don't let... |
828 |
struct user_namespace *ns, int cap_setid, |
22d917d80 userns: Rework th... |
829 830 |
struct uid_gid_map *new_map) { |
f95d7918b userns: Only allo... |
831 |
const struct cred *cred = file->f_cred; |
0542f17bf userns: Document ... |
832 833 834 |
/* Don't allow mappings that would allow anything that wouldn't * be allowed without the establishment of unprivileged mappings. */ |
f95d7918b userns: Only allo... |
835 836 |
if ((new_map->nr_extents == 1) && (new_map->extent[0].count == 1) && uid_eq(ns->owner, cred->euid)) { |
37657da3c userns: Allow set... |
837 838 839 |
u32 id = new_map->extent[0].lower_first; if (cap_setid == CAP_SETUID) { kuid_t uid = make_kuid(ns->parent, id); |
f95d7918b userns: Only allo... |
840 |
if (uid_eq(uid, cred->euid)) |
37657da3c userns: Allow set... |
841 |
return true; |
68a9a435e kernel/user_names... |
842 |
} else if (cap_setid == CAP_SETGID) { |
37657da3c userns: Allow set... |
843 |
kgid_t gid = make_kgid(ns->parent, id); |
66d2f338e userns: Allow set... |
844 845 |
if (!(ns->flags & USERNS_SETGROUPS_ALLOWED) && gid_eq(gid, cred->egid)) |
37657da3c userns: Allow set... |
846 847 848 |
return true; } } |
f76d207a6 userns: Add kproj... |
849 850 851 |
/* Allow anyone to set a mapping that doesn't require privilege */ if (!cap_valid(cap_setid)) return true; |
22d917d80 userns: Rework th... |
852 853 |
/* Allow the specified ids if we have the appropriate capability * (CAP_SETUID or CAP_SETGID) over the parent user namespace. |
6708075f1 userns: Don't let... |
854 |
* And the opener of the id file also had the approprpiate capability. |
22d917d80 userns: Rework th... |
855 |
*/ |
6708075f1 userns: Don't let... |
856 857 |
if (ns_capable(ns->parent, cap_setid) && file_ns_capable(file, ns->parent, cap_setid)) |
22d917d80 userns: Rework th... |
858 |
return true; |
5c1469de7 user_ns: Introduc... |
859 |
|
22d917d80 userns: Rework th... |
860 |
return false; |
5c1469de7 user_ns: Introduc... |
861 |
} |
6164281ab user_ns: improve ... |
862 |
|
9cc46516d userns: Add a kno... |
863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 |
int proc_setgroups_show(struct seq_file *seq, void *v) { struct user_namespace *ns = seq->private; unsigned long userns_flags = ACCESS_ONCE(ns->flags); seq_printf(seq, "%s ", (userns_flags & USERNS_SETGROUPS_ALLOWED) ? "allow" : "deny"); return 0; } ssize_t proc_setgroups_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct seq_file *seq = file->private_data; struct user_namespace *ns = seq->private; char kbuf[8], *pos; bool setgroups_allowed; ssize_t ret; /* Only allow a very narrow range of strings to be written */ ret = -EINVAL; if ((*ppos != 0) || (count >= sizeof(kbuf))) goto out; /* What was written? */ ret = -EFAULT; if (copy_from_user(kbuf, buf, count)) goto out; kbuf[count] = '\0'; pos = kbuf; /* What is being requested? */ ret = -EINVAL; if (strncmp(pos, "allow", 5) == 0) { pos += 5; setgroups_allowed = true; } else if (strncmp(pos, "deny", 4) == 0) { pos += 4; setgroups_allowed = false; } else goto out; /* Verify there is not trailing junk on the line */ pos = skip_spaces(pos); if (*pos != '\0') goto out; ret = -EPERM; mutex_lock(&userns_state_mutex); if (setgroups_allowed) { /* Enabling setgroups after setgroups has been disabled * is not allowed. */ if (!(ns->flags & USERNS_SETGROUPS_ALLOWED)) goto out_unlock; } else { /* Permanently disabling setgroups after setgroups has * been enabled by writing the gid_map is not allowed. */ if (ns->gid_map.nr_extents != 0) goto out_unlock; ns->flags &= ~USERNS_SETGROUPS_ALLOWED; } mutex_unlock(&userns_state_mutex); /* Report a successful write */ *ppos = count; ret = count; out: return ret; out_unlock: mutex_unlock(&userns_state_mutex); goto out; } |
273d2c67c userns: Don't all... |
941 942 943 |
bool userns_may_setgroups(const struct user_namespace *ns) { bool allowed; |
f0d62aec9 userns: Rename id... |
944 |
mutex_lock(&userns_state_mutex); |
273d2c67c userns: Don't all... |
945 946 947 948 |
/* It is not safe to use setgroups until a gid mapping in * the user namespace has been established. */ allowed = ns->gid_map.nr_extents != 0; |
9cc46516d userns: Add a kno... |
949 950 |
/* Is setgroups allowed? */ allowed = allowed && (ns->flags & USERNS_SETGROUPS_ALLOWED); |
f0d62aec9 userns: Rename id... |
951 |
mutex_unlock(&userns_state_mutex); |
273d2c67c userns: Don't all... |
952 953 954 |
return allowed; } |
d07b846f6 fs: Limit file ca... |
955 956 957 958 959 960 961 962 963 964 965 966 967 |
/* * Returns true if @ns is the same namespace as or a descendant of * @target_ns. */ bool current_in_userns(const struct user_namespace *target_ns) { struct user_namespace *ns; for (ns = current_user_ns(); ns; ns = ns->parent) { if (ns == target_ns) return true; } return false; } |
3c0411846 switch the rest o... |
968 969 970 971 |
static inline struct user_namespace *to_user_ns(struct ns_common *ns) { return container_of(ns, struct user_namespace, ns); } |
64964528b make proc_ns_oper... |
972 |
static struct ns_common *userns_get(struct task_struct *task) |
cde1975bc userns: Implent p... |
973 974 975 976 977 978 |
{ struct user_namespace *user_ns; rcu_read_lock(); user_ns = get_user_ns(__task_cred(task)->user_ns); rcu_read_unlock(); |
3c0411846 switch the rest o... |
979 |
return user_ns ? &user_ns->ns : NULL; |
cde1975bc userns: Implent p... |
980 |
} |
64964528b make proc_ns_oper... |
981 |
static void userns_put(struct ns_common *ns) |
cde1975bc userns: Implent p... |
982 |
{ |
3c0411846 switch the rest o... |
983 |
put_user_ns(to_user_ns(ns)); |
cde1975bc userns: Implent p... |
984 |
} |
64964528b make proc_ns_oper... |
985 |
static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns) |
cde1975bc userns: Implent p... |
986 |
{ |
3c0411846 switch the rest o... |
987 |
struct user_namespace *user_ns = to_user_ns(ns); |
cde1975bc userns: Implent p... |
988 989 990 991 992 993 994 |
struct cred *cred; /* Don't allow gaining capabilities by reentering * the same user namespace. */ if (user_ns == current_user_ns()) return -EINVAL; |
faf00da54 userns,pidns: For... |
995 996 |
/* Tasks that share a thread group must share a user namespace */ if (!thread_group_empty(current)) |
cde1975bc userns: Implent p... |
997 |
return -EINVAL; |
e66eded83 userns: Don't all... |
998 999 |
if (current->fs->users != 1) return -EINVAL; |
cde1975bc userns: Implent p... |
1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 |
if (!ns_capable(user_ns, CAP_SYS_ADMIN)) return -EPERM; cred = prepare_creds(); if (!cred) return -ENOMEM; put_user_ns(cred->user_ns); set_cred_user_ns(cred, get_user_ns(user_ns)); return commit_creds(cred); } |
bcac25a58 kernel: add a hel... |
1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 |
struct ns_common *ns_get_owner(struct ns_common *ns) { struct user_namespace *my_user_ns = current_user_ns(); struct user_namespace *owner, *p; /* See if the owner is in the current user namespace */ owner = p = ns->ops->owner(ns); for (;;) { if (!p) return ERR_PTR(-EPERM); if (p == my_user_ns) break; p = p->parent; } return &get_user_ns(owner)->ns; } static struct user_namespace *userns_owner(struct ns_common *ns) { return to_user_ns(ns)->parent; } |
cde1975bc userns: Implent p... |
1034 1035 1036 1037 1038 1039 |
const struct proc_ns_operations userns_operations = { .name = "user", .type = CLONE_NEWUSER, .get = userns_get, .put = userns_put, .install = userns_install, |
bcac25a58 kernel: add a hel... |
1040 |
.owner = userns_owner, |
a7306ed8d nsfs: add ioctl t... |
1041 |
.get_parent = ns_get_owner, |
cde1975bc userns: Implent p... |
1042 |
}; |
6164281ab user_ns: improve ... |
1043 1044 1045 1046 1047 |
static __init int user_namespaces_init(void) { user_ns_cachep = KMEM_CACHE(user_namespace, SLAB_PANIC); return 0; } |
c96d6660d kernel: audit/fix... |
1048 |
subsys_initcall(user_namespaces_init); |