96 lines
2.0 KiB
C
96 lines
2.0 KiB
C
/*
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* Copyright (C) 2004 IBM Corporation
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*
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* Author: Serge Hallyn <serue@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*/
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#include <linux/module.h>
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#include <linux/uts.h>
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#include <linux/utsname.h>
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#include <linux/version.h>
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/*
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* Clone a new ns copying an original utsname, setting refcount to 1
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* @old_ns: namespace to clone
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* Return NULL on error (failure to kmalloc), new ns otherwise
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*/
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static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
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{
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struct uts_namespace *ns;
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ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
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if (ns) {
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memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
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kref_init(&ns->kref);
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}
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return ns;
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}
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/*
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* unshare the current process' utsname namespace.
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* called only in sys_unshare()
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*/
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int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts)
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{
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if (unshare_flags & CLONE_NEWUTS) {
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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*new_uts = clone_uts_ns(current->nsproxy->uts_ns);
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if (!*new_uts)
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return -ENOMEM;
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}
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return 0;
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}
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/*
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* Copy task tsk's utsname namespace, or clone it if flags
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* specifies CLONE_NEWUTS. In latter case, changes to the
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* utsname of this process won't be seen by parent, and vice
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* versa.
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*/
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int copy_utsname(int flags, struct task_struct *tsk)
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{
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struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
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struct uts_namespace *new_ns;
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int err = 0;
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if (!old_ns)
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return 0;
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get_uts_ns(old_ns);
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if (!(flags & CLONE_NEWUTS))
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return 0;
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if (!capable(CAP_SYS_ADMIN)) {
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err = -EPERM;
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goto out;
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}
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new_ns = clone_uts_ns(old_ns);
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if (!new_ns) {
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err = -ENOMEM;
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goto out;
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}
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tsk->nsproxy->uts_ns = new_ns;
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out:
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put_uts_ns(old_ns);
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return err;
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}
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void free_uts_ns(struct kref *kref)
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{
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struct uts_namespace *ns;
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ns = container_of(kref, struct uts_namespace, kref);
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kfree(ns);
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}
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