path: root/security/keys/keyctl.c

/* keyctl.c: userspace keyctl operations
 *
 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
 * 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>
#include <linux/err.h>
#include <asm/uaccess.h>
#include "internal.h"

/*****************************************************************************/
/*
 * 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)
{
	key_ref_t keyring_ref, key_ref;
	char type[32], *description;
	void *payload;
	long dlen, ret;

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

	/* draw all the data into kernel space */
	ret = strncpy_from_user(type, _type, sizeof(type) - 1);
	if (ret < 0)
		goto error;
	type[31] = '\0';

	ret = -EPERM;
	if (type[0] == '.')
		goto error;

	ret = -EFAULT;
	dlen = strnlen_user(_description, PAGE_SIZE - 1);
	if (dlen <= 0)
		goto error;

	ret = -EINVAL;
	if (dlen > PAGE_SIZE - 1)
		goto error;

	ret = -ENOMEM;
	description = kmalloc(dlen + 1, GFP_KERNEL);
	if (!description)
		goto error;

	ret = -EFAULT;
	if (copy_from_user(description, _description, dlen + 1) != 0)
		goto error2;

	/* 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) */
	keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);
		goto error3;
	}

	/* create or update the requested key and add it to the target
	 * keyring */
	key_ref = key_create_or_update(keyring_ref, type, description,
				       payload, plen, 0);
	if (!IS_ERR(key_ref)) {
		ret = key_ref_to_ptr(key_ref)->serial;
		key_ref_put(key_ref);
	}
	else {
		ret = PTR_ERR(key_ref);
	}

	key_ref_put(keyring_ref);
 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;
	struct key *key;
	key_ref_t dest_ref;
	char type[32], *description, *callout_info;
	long dlen, ret;

	/* pull the type into kernel space */