path: root/net/rxrpc/ar-key.c

/* RxRPC key management
 *
 * Copyright (C) 2007 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.
 *
 * RxRPC keys should have a description of describing their purpose:
 *	"afs@CAMBRIDGE.REDHAT.COM>
 */

#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/key-type.h>
#include <linux/crypto.h>
#include <linux/ctype.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <keys/rxrpc-type.h>
#include <keys/user-type.h>
#include "ar-internal.h"

static int rxrpc_vet_description_s(const char *);
static int rxrpc_preparse(struct key_preparsed_payload *);
static int rxrpc_preparse_s(struct key_preparsed_payload *);
static void rxrpc_free_preparse(struct key_preparsed_payload *);
static void rxrpc_free_preparse_s(struct key_preparsed_payload *);
static void rxrpc_destroy(struct key *);
static void rxrpc_destroy_s(struct key *);
static void rxrpc_describe(const struct key *, struct seq_file *);
static long rxrpc_read(const struct key *, char __user *, size_t);

/*
 * rxrpc defined keys take an arbitrary string as the description and an
 * arbitrary blob of data as the payload
 */
struct key_type key_type_rxrpc = {
	.name		= "rxrpc",
	.preparse	= rxrpc_preparse,
	.free_preparse	= rxrpc_free_preparse,
	.instantiate	= generic_key_instantiate,
	.destroy	= rxrpc_destroy,
	.describe	= rxrpc_describe,
	.read		= rxrpc_read,
};
EXPORT_SYMBOL(key_type_rxrpc);

/*
 * rxrpc server defined keys take "<serviceId>:<securityIndex>" as the
 * description and an 8-byte decryption key as the payload
 */
struct key_type key_type_rxrpc_s = {
	.name		= "rxrpc_s",
	.vet_description = rxrpc_vet_description_s,
	.preparse	= rxrpc_preparse_s,
	.free_preparse	= rxrpc_free_preparse_s,
	.instantiate	= generic_key_instantiate,
	.destroy	= rxrpc_destroy_s,
	.describe	= rxrpc_describe,
};

/*
 * Vet the description for an RxRPC server key
 */
static int rxrpc_vet_description_s(const char *desc)
{
	unsigned long num;
	char *p;

	num = simple_strtoul(desc, &p, 10);
	if (*p != ':' || num > 65535)
		return -EINVAL;
	num = simple_strtoul(p + 1, &p, 10);
	if (*p || num < 1 || num > 255)
		return -EINVAL;
	return 0;
}

/*
 * parse an RxKAD type XDR format token
 * - the caller guarantees we have at least 4 words
 */
static int rxrpc_preparse_xdr_rxkad(struct key_preparsed_payload *prep,
				    size_t datalen,
				    const __be32 *xdr, unsigned int toklen)
{
	struct rxrpc_key_token *token, **pptoken;
	size_t plen;
	u32 tktlen;

	_enter(",{%x,%x,%x,%x},%u",
	       ntohl(xdr[0]), ntohl(xdr[1]), ntohl(xdr[2]), ntohl(xdr[3]),
	       toklen);

	if (toklen <= 8 * 4)
		return -EKEYREJECTED;
	tktlen = ntohl(xdr[7]);
	_debug("tktlen: %x", tktlen);
	if (tktlen > AFSTOKEN_RK_TIX_MAX)
		return -EKEYREJECTED;
	if (toklen < 8 * 4 + tktlen)
		return -EKEYREJECTED;

	plen = sizeof(*token) + sizeof(*token->kad) + tktlen;
	prep->quotalen = datalen + plen;

	plen -= sizeof