linux-imx

// 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/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);

}

​

static struct uts_namespace *create_uts_ns(void)

{

    struct uts_namespace *uts_ns;

​

    uts_ns = kmem_cache_alloc(uts_ns_cache, GFP_KERNEL);

    if (uts_ns)

        kref_init(&uts_ns->kref);

    return uts_ns;

}

​

/*

 * 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 = create_uts_ns();

    if (!ns)

        goto fail_dec;

​

    err = ns_alloc_inum(&ns->ns);

    if (err)

        goto fail_free;

​

    ns->ucounts = ucounts;

    ns->ns.ops = &utsns_operations;

​

    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);

    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(unsigned long flags,

    struct user_namespace *user_ns, struct uts_namespace *old_ns)

{

    struct uts_namespace *new_ns;