keyctl.c 26.2 KB
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/* keyctl.c: userspace keyctl operations
 *
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 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
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 * Written by David Howells (dhowells@redhat.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; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/keyctl.h>
#include <linux/fs.h>
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#include <linux/capability.h>
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#include <linux/string.h>
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#include <linux/err.h>
#include <asm/uaccess.h>
#include "internal.h"

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static int key_get_type_from_user(char *type,
				  const char __user *_type,
				  unsigned len)
{
	int ret;

	ret = strncpy_from_user(type, _type, len);

	if (ret < 0)
		return -EFAULT;

	if (ret == 0 || ret >= len)
		return -EINVAL;

	if (type[0] == '.')
		return -EPERM;

	type[len - 1] = '\0';

	return 0;
}

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/*****************************************************************************/
/*
 * extract the description of a new key from userspace and either add it as a
 * new key to the specified keyring or update a matching key in that keyring
 * - the keyring must be writable
 * - returns the new key's serial number
 * - implements add_key()
 */
asmlinkage long sys_add_key(const char __user *_type,
			    const char __user *_description,
			    const void __user *_payload,
			    size_t plen,
			    key_serial_t ringid)
{
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	key_ref_t keyring_ref, key_ref;
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	char type[32], *description;
	void *payload;
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	long ret;
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	ret = -EINVAL;
	if (plen > 32767)
		goto error;

	/* draw all the data into kernel space */
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	ret = key_get_type_from_user(type, _type, sizeof(type));
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	if (ret < 0)
		goto error;

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	description = strndup_user(_description, PAGE_SIZE);
	if (IS_ERR(description)) {
		ret = PTR_ERR(description);
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		goto error;
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	}
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	/* pull the payload in if one was supplied */
	payload = NULL;

	if (_payload) {
		ret = -ENOMEM;
		payload = kmalloc(plen, GFP_KERNEL);
		if (!payload)
			goto error2;

		ret = -EFAULT;
		if (copy_from_user(payload, _payload, plen) != 0)
			goto error3;
	}

	/* find the target keyring (which must be writable) */
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	keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);
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		goto error3;
	}

	/* create or update the requested key and add it to the target
	 * keyring */
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	key_ref = key_create_or_update(keyring_ref, type, description,
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				       payload, plen, KEY_ALLOC_IN_QUOTA);
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	if (!IS_ERR(key_ref)) {
		ret = key_ref_to_ptr(key_ref)->serial;
		key_ref_put(key_ref);
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	}
	else {
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		ret = PTR_ERR(key_ref);
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	}

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	key_ref_put(keyring_ref);
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 error3:
	kfree(payload);
 error2:
	kfree(description);
 error:
	return ret;

} /* end sys_add_key() */

/*****************************************************************************/
/*
 * search the process keyrings for a matching key
 * - nested keyrings may also be searched if they have Search permission
 * - if a key is found, it will be attached to the destination keyring if
 *   there's one specified
 * - /sbin/request-key will be invoked if _callout_info is non-NULL
 *   - the _callout_info string will be passed to /sbin/request-key
 *   - if the _callout_info string is empty, it will be rendered as "-"
 * - implements request_key()
 */
asmlinkage long sys_request_key(const char __user *_type,
				const char __user *_description,
				const char __user *_callout_info,
				key_serial_t destringid)
{
	struct key_type *ktype;
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	struct key *key;
	key_ref_t dest_ref;
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	char type[32], *description, *callout_info;
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	long ret;
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	/* pull the type into kernel space */
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	ret = key_get_type_from_user(type, _type, sizeof(type));
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	if (ret < 0)
		goto error;
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	/* pull the description into kernel space */
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	description = strndup_user(_description, PAGE_SIZE);
	if (IS_ERR(description)) {
		ret = PTR_ERR(description);
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		goto error;
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	}
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	/* pull the callout info into kernel space */
	callout_info = NULL;
	if (_callout_info) {
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		callout_info = strndup_user(_callout_info, PAGE_SIZE);
		if (IS_ERR(callout_info)) {
			ret = PTR_ERR(callout_info);
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			goto error2;
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		}
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	}

	/* get the destination keyring if specified */
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	dest_ref = NULL;
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	if (destringid) {
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		dest_ref = lookup_user_key(NULL, destringid, 1, 0, KEY_WRITE);
		if (IS_ERR(dest_ref)) {
			ret = PTR_ERR(dest_ref);
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			goto error3;
		}
	}

	/* find the key type */
	ktype = key_type_lookup(type);
	if (IS_ERR(ktype)) {
		ret = PTR_ERR(ktype);
		goto error4;
	}

	/* do the search */
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	key = request_key_and_link(ktype, description, callout_info,
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				   key_ref_to_ptr(dest_ref),
				   KEY_ALLOC_IN_QUOTA);
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	if (IS_ERR(key)) {
		ret = PTR_ERR(key);
		goto error5;
	}

	ret = key->serial;

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 	key_put(key);
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 error5:
	key_type_put(ktype);
 error4:
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	key_ref_put(dest_ref);
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 error3:
	kfree(callout_info);
 error2:
	kfree(description);
 error:
	return ret;

} /* end sys_request_key() */

/*****************************************************************************/
/*
 * get the ID of the specified process keyring
 * - the keyring must have search permission to be found
 * - implements keyctl(KEYCTL_GET_KEYRING_ID)
 */
long keyctl_get_keyring_ID(key_serial_t id, int create)
{
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	key_ref_t key_ref;
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	long ret;

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	key_ref = lookup_user_key(NULL, id, create, 0, KEY_SEARCH);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
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		goto error;
	}

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	ret = key_ref_to_ptr(key_ref)->serial;
	key_ref_put(key_ref);
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 error:
	return ret;

} /* end keyctl_get_keyring_ID() */

/*****************************************************************************/
/*
 * join the session keyring
 * - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING)
 */
long keyctl_join_session_keyring(const char __user *_name)
{
	char *name;
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	long ret;
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	/* fetch the name from userspace */
	name = NULL;
	if (_name) {
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		name = strndup_user(_name, PAGE_SIZE);
		if (IS_ERR(name)) {
			ret = PTR_ERR(name);
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			goto error;
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		}
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	}

	/* join the session */
	ret = join_session_keyring(name);

 error:
	return ret;

} /* end keyctl_join_session_keyring() */

/*****************************************************************************/
/*
 * update a key's data payload
 * - the key must be writable
 * - implements keyctl(KEYCTL_UPDATE)
 */
long keyctl_update_key(key_serial_t id,
		       const void __user *_payload,
		       size_t plen)
{
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	key_ref_t key_ref;
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	void *payload;
	long ret;

	ret = -EINVAL;
	if (plen > PAGE_SIZE)
		goto error;

	/* pull the payload in if one was supplied */
	payload = NULL;
	if (_payload) {
		ret = -ENOMEM;
		payload = kmalloc(plen, GFP_KERNEL);
		if (!payload)
			goto error;

		ret = -EFAULT;
		if (copy_from_user(payload, _payload, plen) != 0)
			goto error2;
	}

	/* find the target key (which must be writable) */
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	key_ref = lookup_user_key(NULL, id, 0, 0, KEY_WRITE);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
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		goto error2;
	}

	/* update the key */
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	ret = key_update(key_ref, payload, plen);
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	key_ref_put(key_ref);
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 error2:
	kfree(payload);
 error:
	return ret;

} /* end keyctl_update_key() */

/*****************************************************************************/
/*
 * revoke a key
 * - the key must be writable
 * - implements keyctl(KEYCTL_REVOKE)
 */
long keyctl_revoke_key(key_serial_t id)
{
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	key_ref_t key_ref;
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	long ret;

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	key_ref = lookup_user_key(NULL, id, 0, 0, KEY_WRITE);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
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		goto error;
	}

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	key_revoke(key_ref_to_ptr(key_ref));
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	ret = 0;

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	key_ref_put(key_ref);
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 error:
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	return ret;
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} /* end keyctl_revoke_key() */

/*****************************************************************************/
/*
 * clear the specified process keyring
 * - the keyring must be writable
 * - implements keyctl(KEYCTL_CLEAR)
 */
long keyctl_keyring_clear(key_serial_t ringid)
{
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	key_ref_t keyring_ref;
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	long ret;

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	keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);
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		goto error;
	}

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	ret = keyring_clear(key_ref_to_ptr(keyring_ref));
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	key_ref_put(keyring_ref);
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 error:
	return ret;

} /* end keyctl_keyring_clear() */

/*****************************************************************************/
/*
 * link a key into a keyring
 * - the keyring must be writable
 * - the key must be linkable
 * - implements keyctl(KEYCTL_LINK)
 */
long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
{
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	key_ref_t keyring_ref, key_ref;
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	long ret;

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	keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);
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		goto error;
	}

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	key_ref = lookup_user_key(NULL, id, 1, 0, KEY_LINK);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
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		goto error2;
	}

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	ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
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	key_ref_put(key_ref);
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 error2:
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	key_ref_put(keyring_ref);
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 error:
	return ret;

} /* end keyctl_keyring_link() */

/*****************************************************************************/
/*
 * unlink the first attachment of a key from a keyring
 * - the keyring must be writable
 * - we don't need any permissions on the key
 * - implements keyctl(KEYCTL_UNLINK)
 */
long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
{
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	key_ref_t keyring_ref, key_ref;
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	long ret;

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	keyring_ref = lookup_user_key(NULL, ringid, 0, 0, KEY_WRITE);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);
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		goto error;
	}

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	key_ref = lookup_user_key(NULL, id, 0, 0, 0);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
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		goto error2;
	}

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	ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
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	key_ref_put(key_ref);
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 error2:
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	key_ref_put(keyring_ref);
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 error:
	return ret;

} /* end keyctl_keyring_unlink() */

/*****************************************************************************/
/*
 * describe a user key
 * - the key must have view permission
 * - if there's a buffer, we place up to buflen bytes of data into it
 * - unless there's an error, we return the amount of description available,
 *   irrespective of how much we may have copied
 * - the description is formatted thus:
 *	type;uid;gid;perm;description<NUL>
 * - implements keyctl(KEYCTL_DESCRIBE)
 */
long keyctl_describe_key(key_serial_t keyid,
			 char __user *buffer,
			 size_t buflen)
{
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	struct key *key, *instkey;
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	key_ref_t key_ref;
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	char *tmpbuf;
	long ret;

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	key_ref = lookup_user_key(NULL, keyid, 0, 1, KEY_VIEW);
	if (IS_ERR(key_ref)) {
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		/* viewing a key under construction is permitted if we have the
		 * authorisation token handy */
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		if (PTR_ERR(key_ref) == -EACCES) {
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			instkey = key_get_instantiation_authkey(keyid);
			if (!IS_ERR(instkey)) {
				key_put(instkey);
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				key_ref = lookup_user_key(NULL, keyid,
							  0, 1, 0);
				if (!IS_ERR(key_ref))
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					goto okay;
			}
		}

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		ret = PTR_ERR(key_ref);
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		goto error;
	}

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okay:
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	/* calculate how much description we're going to return */
	ret = -ENOMEM;
	tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!tmpbuf)
		goto error2;

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	key = key_ref_to_ptr(key_ref);

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	ret = snprintf(tmpbuf, PAGE_SIZE - 1,
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		       "%s;%d;%d;%08x;%s",
		       key_ref_to_ptr(key_ref)->type->name,
		       key_ref_to_ptr(key_ref)->uid,
		       key_ref_to_ptr(key_ref)->gid,
		       key_ref_to_ptr(key_ref)->perm,
		       key_ref_to_ptr(key_ref)->description ?
		       key_ref_to_ptr(key_ref)->description : ""
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		       );

	/* include a NUL char at the end of the data */
	if (ret > PAGE_SIZE - 1)
		ret = PAGE_SIZE - 1;
	tmpbuf[ret] = 0;
	ret++;

	/* consider returning the data */
	if (buffer && buflen > 0) {
		if (buflen > ret)
			buflen = ret;

		if (copy_to_user(buffer, tmpbuf, buflen) != 0)
			ret = -EFAULT;
	}

	kfree(tmpbuf);
 error2:
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	key_ref_put(key_ref);
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 error:
	return ret;

} /* end keyctl_describe_key() */

/*****************************************************************************/
/*
 * search the specified keyring for a matching key
 * - the start keyring must be searchable
 * - nested keyrings may also be searched if they are searchable
 * - only keys with search permission may be found
 * - if a key is found, it will be attached to the destination keyring if
 *   there's one specified
 * - implements keyctl(KEYCTL_SEARCH)
 */
long keyctl_keyring_search(key_serial_t ringid,
			   const char __user *_type,
			   const char __user *_description,
			   key_serial_t destringid)
{
	struct key_type *ktype;
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	key_ref_t keyring_ref, key_ref, dest_ref;
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	char type[32], *description;
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	long ret;
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	/* pull the type and description into kernel space */
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	ret = key_get_type_from_user(type, _type, sizeof(type));
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	if (ret < 0)
		goto error;

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	description = strndup_user(_description, PAGE_SIZE);
	if (IS_ERR(description)) {
		ret = PTR_ERR(description);
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		goto error;
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	}
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	/* get the keyring at which to begin the search */
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	keyring_ref = lookup_user_key(NULL, ringid, 0, 0, KEY_SEARCH);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);
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		goto error2;
	}

	/* get the destination keyring if specified */
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	dest_ref = NULL;
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	if (destringid) {
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		dest_ref = lookup_user_key(NULL, destringid, 1, 0, KEY_WRITE);
		if (IS_ERR(dest_ref)) {
			ret = PTR_ERR(dest_ref);
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			goto error3;
		}
	}

	/* find the key type */
	ktype = key_type_lookup(type);
	if (IS_ERR(ktype)) {
		ret = PTR_ERR(ktype);
		goto error4;
	}

	/* do the search */
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	key_ref = keyring_search(keyring_ref, ktype, description);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
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		/* treat lack or presence of a negative key the same */
		if (ret == -EAGAIN)
			ret = -ENOKEY;
		goto error5;
	}

	/* link the resulting key to the destination keyring if we can */
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	if (dest_ref) {
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		ret = key_permission(key_ref, KEY_LINK);
		if (ret < 0)
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			goto error6;

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		ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
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		if (ret < 0)
			goto error6;
	}

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	ret = key_ref_to_ptr(key_ref)->serial;
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 error6:
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	key_ref_put(key_ref);
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 error5:
	key_type_put(ktype);
 error4:
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	key_ref_put(dest_ref);
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 error3:
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	key_ref_put(keyring_ref);
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 error2:
	kfree(description);
 error:
	return ret;

} /* end keyctl_keyring_search() */

/*****************************************************************************/
/*
 * read a user key's payload
 * - the keyring must be readable or the key must be searchable from the
 *   process's keyrings
 * - if there's a buffer, we place up to buflen bytes of data into it
 * - unless there's an error, we return the amount of data in the key,
 *   irrespective of how much we may have copied
 * - implements keyctl(KEYCTL_READ)
 */
long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
{
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	struct key *key;
	key_ref_t key_ref;
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	long ret;

	/* find the key first */
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	key_ref = lookup_user_key(NULL, keyid, 0, 0, 0);
	if (IS_ERR(key_ref)) {
		ret = -ENOKEY;
		goto error;
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	}

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	key = key_ref_to_ptr(key_ref);

	/* see if we can read it directly */
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	ret = key_permission(key_ref, KEY_READ);
	if (ret == 0)
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		goto can_read_key;
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	if (ret != -EACCES)
		goto error;
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	/* we can't; see if it's searchable from this process's keyrings
	 * - we automatically take account of the fact that it may be
	 *   dangling off an instantiation key
	 */
	if (!is_key_possessed(key_ref)) {
		ret = -EACCES;
		goto error2;
	}
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	/* the key is probably readable - now try to read it */
 can_read_key:
	ret = key_validate(key);
	if (ret == 0) {
		ret = -EOPNOTSUPP;
		if (key->type->read) {
			/* read the data with the semaphore held (since we
			 * might sleep) */
			down_read(&key->sem);
			ret = key->type->read(key, buffer, buflen);
			up_read(&key->sem);
		}
	}

 error2:
	key_put(key);
 error:
	return ret;

} /* end keyctl_read_key() */

/*****************************************************************************/
/*
 * change the ownership of a key
 * - the keyring owned by the changer
 * - if the uid or gid is -1, then that parameter is not changed
 * - implements keyctl(KEYCTL_CHOWN)
 */
long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
{
676
	struct key_user *newowner, *zapowner = NULL;
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	struct key *key;
678
	key_ref_t key_ref;
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	long ret;

	ret = 0;
	if (uid == (uid_t) -1 && gid == (gid_t) -1)
		goto error;

685
	key_ref = lookup_user_key(NULL, id, 1, 1, KEY_SETATTR);
686 687
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
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		goto error;
	}

691 692
	key = key_ref_to_ptr(key_ref);

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	/* make the changes with the locks held to prevent chown/chown races */
	ret = -EACCES;
	down_write(&key->sem);

	if (!capable(CAP_SYS_ADMIN)) {
		/* only the sysadmin can chown a key to some other UID */
		if (uid != (uid_t) -1 && key->uid != uid)
700
			goto error_put;
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		/* only the sysadmin can set the key's GID to a group other
		 * than one of those that the current process subscribes to */
		if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
705
			goto error_put;
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	}

708
	/* change the UID */
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	if (uid != (uid_t) -1 && uid != key->uid) {
710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743
		ret = -ENOMEM;
		newowner = key_user_lookup(uid);
		if (!newowner)
			goto error_put;

		/* transfer the quota burden to the new user */
		if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
			spin_lock(&newowner->lock);
			if (newowner->qnkeys + 1 >= KEYQUOTA_MAX_KEYS ||
			    newowner->qnbytes + key->quotalen >=
			    KEYQUOTA_MAX_BYTES)
				goto quota_overrun;

			newowner->qnkeys++;
			newowner->qnbytes += key->quotalen;
			spin_unlock(&newowner->lock);

			spin_lock(&key->user->lock);
			key->user->qnkeys--;
			key->user->qnbytes -= key->quotalen;
			spin_unlock(&key->user->lock);
		}

		atomic_dec(&key->user->nkeys);
		atomic_inc(&newowner->nkeys);

		if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
			atomic_dec(&key->user->nikeys);
			atomic_inc(&newowner->nikeys);
		}

		zapowner = key->user;
		key->user = newowner;
		key->uid = uid;
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	}

	/* change the GID */
	if (gid != (gid_t) -1)
		key->gid = gid;

	ret = 0;

752
error_put:
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	up_write(&key->sem);
	key_put(key);
755 756 757
	if (zapowner)
		key_user_put(zapowner);
error:
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	return ret;

760 761 762 763 764 765
quota_overrun:
	spin_unlock(&newowner->lock);
	zapowner = newowner;
	ret = -EDQUOT;
	goto error_put;

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} /* end keyctl_chown_key() */

/*****************************************************************************/
/*
 * change the permission mask on a key
 * - the keyring owned by the changer
 * - implements keyctl(KEYCTL_SETPERM)
 */
long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
{
	struct key *key;
777
	key_ref_t key_ref;
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	long ret;

	ret = -EINVAL;
781
	if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
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		goto error;

784
	key_ref = lookup_user_key(NULL, id, 1, 1, KEY_SETATTR);
785 786
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
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		goto error;
	}

790 791
	key = key_ref_to_ptr(key_ref);

792
	/* make the changes with the locks held to prevent chown/chmod races */
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	ret = -EACCES;
	down_write(&key->sem);

796 797 798 799 800
	/* if we're not the sysadmin, we can only change a key that we own */
	if (capable(CAP_SYS_ADMIN) || key->uid == current->fsuid) {
		key->perm = perm;
		ret = 0;
	}
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	up_write(&key->sem);
	key_put(key);
804
error:
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	return ret;

} /* end keyctl_setperm_key() */

/*****************************************************************************/
/*
 * instantiate the key with the specified payload, and, if one is given, link
 * the key into the keyring
 */
long keyctl_instantiate_key(key_serial_t id,
			    const void __user *_payload,
			    size_t plen,
			    key_serial_t ringid)
{
819
	struct request_key_auth *rka;
820 821
	struct key *instkey;
	key_ref_t keyring_ref;
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	void *payload;
	long ret;

	ret = -EINVAL;
	if (plen > 32767)
		goto error;

829 830 831 832 833 834 835 836 837 838 839
	/* the appropriate instantiation authorisation key must have been
	 * assumed before calling this */
	ret = -EPERM;
	instkey = current->request_key_auth;
	if (!instkey)
		goto error;

	rka = instkey->payload.data;
	if (rka->target_key->serial != id)
		goto error;

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	/* pull the payload in if one was supplied */
	payload = NULL;

	if (_payload) {
		ret = -ENOMEM;
		payload = kmalloc(plen, GFP_KERNEL);
		if (!payload)
			goto error;

		ret = -EFAULT;
		if (copy_from_user(payload, _payload, plen) != 0)
			goto error2;
	}

854 855
	/* find the destination keyring amongst those belonging to the
	 * requesting task */
856
	keyring_ref = NULL;
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	if (ringid) {
858 859 860 861
		keyring_ref = lookup_user_key(rka->context, ringid, 1, 0,
					      KEY_WRITE);
		if (IS_ERR(keyring_ref)) {
			ret = PTR_ERR(keyring_ref);
862
			goto error2;
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		}
	}

	/* instantiate the key and link it into a keyring */
867
	ret = key_instantiate_and_link(rka->target_key, payload, plen,
868
				       key_ref_to_ptr(keyring_ref), instkey);
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870
	key_ref_put(keyring_ref);
871 872 873 874 875 876 877 878 879

	/* discard the assumed authority if it's just been disabled by
	 * instantiation of the key */
	if (ret == 0) {
		key_put(current->request_key_auth);
		current->request_key_auth = NULL;
	}

error2:
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	kfree(payload);
881
error:
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	return ret;

} /* end keyctl_instantiate_key() */

/*****************************************************************************/
/*
 * negatively instantiate the key with the given timeout (in seconds), and, if
 * one is given, link the key into the keyring
 */
long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
{
893
	struct request_key_auth *rka;
894 895
	struct key *instkey;
	key_ref_t keyring_ref;
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	long ret;

898 899 900 901 902
	/* the appropriate instantiation authorisation key must have been
	 * assumed before calling this */
	ret = -EPERM;
	instkey = current->request_key_auth;
	if (!instkey)
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		goto error;

905
	rka = instkey->payload.data;
906 907
	if (rka->target_key->serial != id)
		goto error;
908

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	/* find the destination keyring if present (which must also be
	 * writable) */
911
	keyring_ref = NULL;
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	if (ringid) {
913 914 915
		keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
		if (IS_ERR(keyring_ref)) {
			ret = PTR_ERR(keyring_ref);
916
			goto error;
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		}
	}

	/* instantiate the key and link it into a keyring */
921 922
	ret = key_negate_and_link(rka->target_key, timeout,
				  key_ref_to_ptr(keyring_ref), instkey);
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924
	key_ref_put(keyring_ref);
925 926 927 928 929 930 931 932 933

	/* discard the assumed authority if it's just been disabled by
	 * instantiation of the key */
	if (ret == 0) {
		key_put(current->request_key_auth);
		current->request_key_auth = NULL;
	}

error:
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	return ret;

} /* end keyctl_negate_key() */

938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975
/*****************************************************************************/
/*
 * set the default keyring in which request_key() will cache keys
 * - return the old setting
 */
long keyctl_set_reqkey_keyring(int reqkey_defl)
{
	int ret;

	switch (reqkey_defl) {
	case KEY_REQKEY_DEFL_THREAD_KEYRING:
		ret = install_thread_keyring(current);
		if (ret < 0)
			return ret;
		goto set;

	case KEY_REQKEY_DEFL_PROCESS_KEYRING:
		ret = install_process_keyring(current);
		if (ret < 0)
			return ret;

	case KEY_REQKEY_DEFL_DEFAULT:
	case KEY_REQKEY_DEFL_SESSION_KEYRING:
	case KEY_REQKEY_DEFL_USER_KEYRING:
	case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
	set:
		current->jit_keyring = reqkey_defl;

	case KEY_REQKEY_DEFL_NO_CHANGE:
		return current->jit_keyring;

	case KEY_REQKEY_DEFL_GROUP_KEYRING:
	default:
		return -EINVAL;
	}

} /* end keyctl_set_reqkey_keyring() */

976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015
/*****************************************************************************/
/*
 * set or clear the timeout for a key
 */
long keyctl_set_timeout(key_serial_t id, unsigned timeout)
{
	struct timespec now;
	struct key *key;
	key_ref_t key_ref;
	time_t expiry;
	long ret;

	key_ref = lookup_user_key(NULL, id, 1, 1, KEY_SETATTR);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
		goto error;
	}

	key = key_ref_to_ptr(key_ref);

	/* make the changes with the locks held to prevent races */
	down_write(&key->sem);

	expiry = 0;
	if (timeout > 0) {
		now = current_kernel_time();
		expiry = now.tv_sec + timeout;
	}

	key->expiry = expiry;

	up_write(&key->sem);
	key_put(key);

	ret = 0;
error:
	return ret;

} /* end keyctl_set_timeout() */

1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057
/*****************************************************************************/
/*
 * assume the authority to instantiate the specified key
 */
long keyctl_assume_authority(key_serial_t id)
{
	struct key *authkey;
	long ret;

	/* special key IDs aren't permitted */
	ret = -EINVAL;
	if (id < 0)
		goto error;

	/* we divest ourselves of authority if given an ID of 0 */
	if (id == 0) {
		key_put(current->request_key_auth);
		current->request_key_auth = NULL;
		ret = 0;
		goto error;
	}

	/* attempt to assume the authority temporarily granted to us whilst we
	 * instantiate the specified key
	 * - the authorisation key must be in the current task's keyrings
	 *   somewhere
	 */
	authkey = key_get_instantiation_authkey(id);
	if (IS_ERR(authkey)) {
		ret = PTR_ERR(authkey);
		goto error;
	}

	key_put(current->request_key_auth);
	current->request_key_auth = authkey;
	ret = authkey->serial;

error:
	return ret;

} /* end keyctl_assume_authority() */

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1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127
/*****************************************************************************/
/*
 * the key control system call
 */
asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3,
			   unsigned long arg4, unsigned long arg5)
{
	switch (option) {
	case KEYCTL_GET_KEYRING_ID:
		return keyctl_get_keyring_ID((key_serial_t) arg2,
					     (int) arg3);

	case KEYCTL_JOIN_SESSION_KEYRING:
		return keyctl_join_session_keyring((const char __user *) arg2);

	case KEYCTL_UPDATE:
		return keyctl_update_key((key_serial_t) arg2,
					 (const void __user *) arg3,
					 (size_t) arg4);

	case KEYCTL_REVOKE:
		return keyctl_revoke_key((key_serial_t) arg2);

	case KEYCTL_DESCRIBE:
		return keyctl_describe_key((key_serial_t) arg2,
					   (char __user *) arg3,
					   (unsigned) arg4);

	case KEYCTL_CLEAR:
		return keyctl_keyring_clear((key_serial_t) arg2);

	case KEYCTL_LINK:
		return keyctl_keyring_link((key_serial_t) arg2,
					   (key_serial_t) arg3);

	case KEYCTL_UNLINK:
		return keyctl_keyring_unlink((key_serial_t) arg2,
					     (key_serial_t) arg3);

	case KEYCTL_SEARCH:
		return keyctl_keyring_search((key_serial_t) arg2,
					     (const char __user *) arg3,
					     (const char __user *) arg4,
					     (key_serial_t) arg5);

	case KEYCTL_READ:
		return keyctl_read_key((key_serial_t) arg2,
				       (char __user *) arg3,
				       (size_t) arg4);

	case KEYCTL_CHOWN:
		return keyctl_chown_key((key_serial_t) arg2,
					(uid_t) arg3,
					(gid_t) arg4);

	case KEYCTL_SETPERM:
		return keyctl_setperm_key((key_serial_t) arg2,
					  (key_perm_t) arg3);

	case KEYCTL_INSTANTIATE:
		return keyctl_instantiate_key((key_serial_t) arg2,
					      (const void __user *) arg3,
					      (size_t) arg4,
					      (key_serial_t) arg5);

	case KEYCTL_NEGATE:
		return keyctl_negate_key((key_serial_t) arg2,
					 (unsigned) arg3,
					 (key_serial_t) arg4);

1128 1129 1130
	case KEYCTL_SET_REQKEY_KEYRING:
		return keyctl_set_reqkey_keyring(arg2);

1131 1132 1133 1134
	case KEYCTL_SET_TIMEOUT:
		return keyctl_set_timeout((key_serial_t) arg2,
					  (unsigned) arg3);

1135 1136 1137
	case KEYCTL_ASSUME_AUTHORITY:
		return keyctl_assume_authority((key_serial_t) arg2);

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	default:
		return -EOPNOTSUPP;
	}

} /* end sys_keyctl() */
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