diff options
Diffstat (limited to 'kernel/utsname.c')
| -rw-r--r-- | kernel/utsname.c | 108 |
1 files changed, 66 insertions, 42 deletions
diff --git a/kernel/utsname.c b/kernel/utsname.c index 2fc8576efaa8..ebbfc578a9d3 100644 --- a/kernel/utsname.c +++ b/kernel/utsname.c @@ -1,12 +1,8 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2004 IBM Corporation * * Author: Serge Hallyn <serue@us.ibm.com> - * - * 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. */ #include <linux/export.h> @@ -14,45 +10,64 @@ #include <linux/utsname.h> #include <linux/err.h> #include <linux/slab.h> +#include <linux/cred.h> #include <linux/user_namespace.h> #include <linux/proc_ns.h> +#include <linux/nstree.h> +#include <linux/sched/task.h> + +static struct kmem_cache *uts_ns_cache __ro_after_init; -static struct uts_namespace *create_uts_ns(void) +static struct ucounts *inc_uts_namespaces(struct user_namespace *ns) { - struct uts_namespace *uts_ns; + return inc_ucount(ns, current_euid(), UCOUNT_UTS_NAMESPACES); +} - uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL); - if (uts_ns) - kref_init(&uts_ns->kref); - return uts_ns; +static void dec_uts_namespaces(struct ucounts *ucounts) +{ + dec_ucount(ucounts, UCOUNT_UTS_NAMESPACES); } /* * Clone a new ns copying an original utsname, setting refcount to 1 * @old_ns: namespace to clone - * Return ERR_PTR(-ENOMEM) on error (failure to kmalloc), new ns otherwise + * Return ERR_PTR(-ENOMEM) on error (failure to allocate), new ns otherwise */ static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, struct uts_namespace *old_ns) { struct uts_namespace *ns; + struct ucounts *ucounts; int err; - ns = create_uts_ns(); + err = -ENOSPC; + ucounts = inc_uts_namespaces(user_ns); + if (!ucounts) + goto fail; + + err = -ENOMEM; + ns = kmem_cache_zalloc(uts_ns_cache, GFP_KERNEL); if (!ns) - return ERR_PTR(-ENOMEM); + goto fail_dec; - err = proc_alloc_inum(&ns->proc_inum); - if (err) { - kfree(ns); - return ERR_PTR(err); - } + err = ns_common_init(ns); + if (err) + goto fail_free; + ns->ucounts = ucounts; down_read(&uts_sem); memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); ns->user_ns = get_user_ns(user_ns); up_read(&uts_sem); + ns_tree_add(ns); return ns; + +fail_free: + kmem_cache_free(uts_ns_cache, ns); +fail_dec: + dec_uts_namespaces(ucounts); +fail: + return ERR_PTR(err); } /* @@ -61,7 +76,7 @@ static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, * utsname of this process won't be seen by parent, and vice * versa. */ -struct uts_namespace *copy_utsname(unsigned long flags, +struct uts_namespace *copy_utsname(u64 flags, struct user_namespace *user_ns, struct uts_namespace *old_ns) { struct uts_namespace *new_ns; @@ -78,43 +93,44 @@ struct uts_namespace *copy_utsname(unsigned long flags, return new_ns; } -void free_uts_ns(struct kref *kref) +void free_uts_ns(struct uts_namespace *ns) { - struct uts_namespace *ns; - - ns = container_of(kref, struct uts_namespace, kref); + ns_tree_remove(ns); + dec_uts_namespaces(ns->ucounts); put_user_ns(ns->user_ns); - proc_free_inum(ns->proc_inum); - kfree(ns); + ns_common_free(ns); + /* Concurrent nstree traversal depends on a grace period. */ + kfree_rcu(ns, ns.ns_rcu); } -static void *utsns_get(struct task_struct *task) +static struct ns_common *utsns_get(struct task_struct *task) { struct uts_namespace *ns = NULL; struct nsproxy *nsproxy; - rcu_read_lock(); - nsproxy = task_nsproxy(task); + task_lock(task); + nsproxy = task->nsproxy; if (nsproxy) { ns = nsproxy->uts_ns; get_uts_ns(ns); } - rcu_read_unlock(); + task_unlock(task); - return ns; + return ns ? &ns->ns : NULL; } -static void utsns_put(void *ns) +static void utsns_put(struct ns_common *ns) { - put_uts_ns(ns); + put_uts_ns(to_uts_ns(ns)); } -static int utsns_install(struct nsproxy *nsproxy, void *new) +static int utsns_install(struct nsset *nsset, struct ns_common *new) { - struct uts_namespace *ns = new; + struct nsproxy *nsproxy = nsset->nsproxy; + struct uts_namespace *ns = to_uts_ns(new); if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || - !nsown_capable(CAP_SYS_ADMIN)) + !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN)) return -EPERM; get_uts_ns(ns); @@ -123,18 +139,26 @@ static int utsns_install(struct nsproxy *nsproxy, void *new) return 0; } -static unsigned int utsns_inum(void *vp) +static struct user_namespace *utsns_owner(struct ns_common *ns) { - struct uts_namespace *ns = vp; - - return ns->proc_inum; + return to_uts_ns(ns)->user_ns; } const struct proc_ns_operations utsns_operations = { .name = "uts", - .type = CLONE_NEWUTS, .get = utsns_get, .put = utsns_put, .install = utsns_install, - .inum = utsns_inum, + .owner = utsns_owner, }; + +void __init uts_ns_init(void) +{ + uts_ns_cache = kmem_cache_create_usercopy( + "uts_namespace", sizeof(struct uts_namespace), 0, + SLAB_PANIC|SLAB_ACCOUNT, + offsetof(struct uts_namespace, name), + sizeof_field(struct uts_namespace, name), + NULL); + ns_tree_add(&init_uts_ns); +} |