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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165// SPDX-License-Identifier: GPL-2.0-only/* * Copyright (C) 2004 IBM Corporation * * Author: Serge Hallyn <serue@us.ibm.com> */
#include <linux/export.h>#include <linux/uts.h>#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 ucounts *inc_uts_namespaces(struct user_namespace *ns){ return inc_ucount(ns, current_euid(), UCOUNT_UTS_NAMESPACES);}
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 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;
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) goto fail_dec;
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);}
/* * Copy task tsk's utsname namespace, or clone it if flags * specifies CLONE_NEWUTS. In latter case, changes to the * utsname of this process won't be seen by parent, and vice * versa. */struct uts_namespace *copy_utsname(u64 flags, struct user_namespace *user_ns, struct uts_namespace *old_ns){ struct uts_namespace *new_ns;
BUG_ON(!old_ns); get_uts_ns(old_ns);
if (!(flags & CLONE_NEWUTS)) return old_ns;
new_ns = clone_uts_ns(user_ns, old_ns);
put_uts_ns(old_ns); return new_ns;}
void free_uts_ns(struct uts_namespace *ns){ ns_tree_remove(ns); dec_uts_namespaces(ns->ucounts); put_user_ns(ns->user_ns); ns_common_free(ns); /* Concurrent nstree traversal depends on a grace period. */ kfree_rcu(ns, ns.ns_rcu);}
static struct ns_common *utsns_get(struct task_struct *task){ struct uts_namespace *ns = NULL; struct nsproxy *nsproxy;
task_lock(task); nsproxy = task->nsproxy; if (nsproxy) { ns = nsproxy->uts_ns; get_uts_ns(ns); } task_unlock(task);
return ns ? &ns->ns : NULL;}
static void utsns_put(struct ns_common *ns){ put_uts_ns(to_uts_ns(ns));}
static int utsns_install(struct nsset *nsset, struct ns_common *new){ struct nsproxy *nsproxy = nsset->nsproxy; struct uts_namespace *ns = to_uts_ns(new);
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN)) return -EPERM;
get_uts_ns(ns); put_uts_ns(nsproxy->uts_ns); nsproxy->uts_ns = ns; return 0;}
static struct user_namespace *utsns_owner(struct ns_common *ns){ return to_uts_ns(ns)->user_ns;}
const struct proc_ns_operations utsns_operations = { .name = "uts", .get = utsns_get, .put = utsns_put, .install = utsns_install, .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);}