[CIFS] Add upcall files for cifs to use spnego/kerberos

/*

 *   fs/cifs/cifs_spnego.c -- SPNEGO upcall management for CIFS

 *

 *   Copyright (c) 2007 Red Hat, Inc.

 *   Author(s): Jeff Layton (jlayton@redhat.com)

 *

 *   This library is free software; you can redistribute it and/or modify

 *   it under the terms of the GNU Lesser General Public License as published

 *   by the Free Software Foundation; either version 2.1 of the License, or

 *   (at your option) any later version.

 *

 *   This library is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See

 *   the GNU Lesser General Public License for more details.

 *

 *   You should have received a copy of the GNU Lesser General Public License

 *   along with this library; if not, write to the Free Software

 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

 */

#include <linux/list.h>

#include <linux/string.h>

#include <keys/user-type.h>

#include <linux/key-type.h>

#include "cifsglob.h"

#include "cifs_spnego.h"

#include "cifs_debug.h"

/* create a new cifs key */

static int

cifs_spnego_key_instantiate(struct key *key, const void *data, size_t datalen)

{

	char *payload;

	int ret;

	ret = -ENOMEM;

	payload = kmalloc(datalen, GFP_KERNEL);

	if (!payload)

		goto error;

	/* attach the data */

	memcpy(payload, data, datalen);

	rcu_assign_pointer(key->payload.data, payload);

	ret = 0;

error:

	return ret;

}

static void

cifs_spnego_key_destroy(struct key *key)

{

	kfree(key->payload.data);

}

/*

 * keytype for CIFS spnego keys

 */

struct key_type cifs_spnego_key_type = {

	.name		= "cifs.spnego",

	.instantiate	= cifs_spnego_key_instantiate,

	.match		= user_match,

	.destroy	= cifs_spnego_key_destroy,

	.describe	= user_describe,

};

/* get a key struct with a SPNEGO security blob, suitable for session setup */

struct key *

cifs_get_spnego_key(struct cifsSesInfo *sesInfo, const char *hostname)

{

	struct TCP_Server_Info *server = sesInfo->server;

	char *description, *dp;

	size_t desc_len;

	struct key *spnego_key;

	/* version + ;ip{4|6}= + address + ;host=hostname + ;sec= + NULL */

	desc_len = 2 + 5 + 32 + 1 + 5 + strlen(hostname) +

		   strlen(";sec=krb5") + 1;

	spnego_key = ERR_PTR(-ENOMEM);

	description = kzalloc(desc_len, GFP_KERNEL);

	if (description == NULL)

		goto out;

	dp = description;

	/* start with version and hostname portion of UNC string */

	spnego_key = ERR_PTR(-EINVAL);

	sprintf(dp, "%2.2x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,

		hostname);

	dp = description + strlen(description);

	/* add the server address */

	if (server->addr.sockAddr.sin_family == AF_INET)

		sprintf(dp, "ip4=" NIPQUAD_FMT,

			NIPQUAD(server->addr.sockAddr.sin_addr));

	else if (server->addr.sockAddr.sin_family == AF_INET6)

		sprintf(dp, "ip6=" NIP6_SEQFMT,

			NIP6(server->addr.sockAddr6.sin6_addr));

	else

		goto out;

	dp = description + strlen(description);

	/* for now, only sec=krb5 is valid */

	if (server->secType == Kerberos)

		sprintf(dp, ";sec=krb5");

	else

		goto out;

	cFYI(1, ("key description = %s", description));

	spnego_key = request_key(&cifs_spnego_key_type, description, "");

	if (cifsFYI && !IS_ERR(spnego_key)) {

		struct cifs_spnego_msg *msg = spnego_key->payload.data;

		cifs_dump_mem("SPNEGO reply blob:", msg->data,

				msg->secblob_len + msg->sesskey_len);

	}

out:

	kfree(description);

	return spnego_key;

}

/*

 *   fs/cifs/cifs_spnego.h -- SPNEGO upcall management for CIFS

 *

 *   Copyright (c) 2007 Red Hat, Inc.

 *   Author(s): Jeff Layton (jlayton@redhat.com)

 *              Steve French (sfrench@us.ibm.com)

 *

 *   This library is free software; you can redistribute it and/or modify

 *   it under the terms of the GNU Lesser General Public License as published

 *   by the Free Software Foundation; either version 2.1 of the License, or

 *   (at your option) any later version.

 *

 *   This library is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See

 *   the GNU Lesser General Public License for more details.

 *

 *   You should have received a copy of the GNU Lesser General Public License

 *   along with this library; if not, write to the Free Software

 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

 */

#ifndef _CIFS_SPNEGO_H

#define _CIFS_SPNEGO_H

#define CIFS_SPNEGO_UPCALL_VERSION 1

/*

 * The version field should always be set to CIFS_SPNEGO_UPCALL_VERSION.

 * The flags field is for future use. The request-key callout should set

 * sesskey_len and secblob_len, and then concatenate the SessKey+SecBlob

 * and stuff it in the data field.

 */

struct cifs_spnego_msg {

	uint32_t	version;

	uint32_t	flags;

	uint32_t	sesskey_len;

	uint32_t	secblob_len;

	uint8_t		data[1];

};

#ifdef __KERNEL__

extern struct key_type cifs_spnego_key_type;

#endif /* KERNEL */

#endif /* _CIFS_SPNEGO_H */