crypto/crypto_user.c - third_party/linux - Git at Google

 /*
  * Crypto user configuration API.
  *
  * Copyright (C) 2011 secunet Security Networks AG
  * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  */

 #include <linux/module.h>
 #include <linux/crypto.h>
 #include <linux/cryptouser.h>
 #include <net/netlink.h>
 #include <linux/security.h>
 #include <net/net_namespace.h>
 #include "internal.h"

 DEFINE_MUTEX(crypto_cfg_mutex);

 /* The crypto netlink socket */
 static struct sock *crypto_nlsk;

 struct crypto_dump_info {
 	struct sk_buff *in_skb;
 	struct sk_buff *out_skb;
 	u32 nlmsg_seq;
 	u16 nlmsg_flags;
 };

 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
 {
 	struct crypto_alg *q, *alg = NULL;

 	down_read(&crypto_alg_sem);

 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
 		int match = 0;

 		if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
 			continue;

 		if (strlen(p->cru_driver_name))
 			match = !strcmp(q->cra_driver_name,
 					p->cru_driver_name);
 		else if (!exact)
 			match = !strcmp(q->cra_name, p->cru_name);

 		if (match) {
 			alg = q;
 			break;
 		}
 	}

 	up_read(&crypto_alg_sem);

 	return alg;
 }

 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
 {
 	struct crypto_report_cipher rcipher;

 	strncpy(rcipher.type, "cipher", sizeof(rcipher.type));

 	rcipher.blocksize = alg->cra_blocksize;
 	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
 	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;

 	NLA_PUT(skb, CRYPTOCFGA_REPORT_CIPHER,
 		sizeof(struct crypto_report_cipher), &rcipher);

 	return 0;

 nla_put_failure:
 	return -EMSGSIZE;
 }

 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
 {
 	struct crypto_report_comp rcomp;

 	strncpy(rcomp.type, "compression", sizeof(rcomp.type));
 	NLA_PUT(skb, CRYPTOCFGA_REPORT_COMPRESS,
 		sizeof(struct crypto_report_comp), &rcomp);

 	return 0;

 nla_put_failure:
 	return -EMSGSIZE;
 }

 static int crypto_report_one(struct crypto_alg *alg,
 			     struct crypto_user_alg *ualg, struct sk_buff *skb)
 {
 	strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 	strncpy(ualg->cru_driver_name, alg->cra_driver_name,
 		sizeof(ualg->cru_driver_name));
 	strncpy(ualg->cru_module_name, module_name(alg->cra_module),
 		sizeof(ualg->cru_module_name));

 	ualg->cru_type = 0;
 	ualg->cru_mask = 0;
 	ualg->cru_flags = alg->cra_flags;
 	ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);

 	NLA_PUT_U32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority);

 	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 		struct crypto_report_larval rl;

 		strncpy(rl.type, "larval", sizeof(rl.type));
 		NLA_PUT(skb, CRYPTOCFGA_REPORT_LARVAL,
 			sizeof(struct crypto_report_larval), &rl);

 		goto out;
 	}

 	if (alg->cra_type && alg->cra_type->report) {
 		if (alg->cra_type->report(skb, alg))
 			goto nla_put_failure;

 		goto out;
 	}

 	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 	case CRYPTO_ALG_TYPE_CIPHER:
 		if (crypto_report_cipher(skb, alg))
 			goto nla_put_failure;

 		break;
 	case CRYPTO_ALG_TYPE_COMPRESS:
 		if (crypto_report_comp(skb, alg))
 			goto nla_put_failure;

 		break;
 	}

 out:
 	return 0;

 nla_put_failure:
 	return -EMSGSIZE;
 }

 static int crypto_report_alg(struct crypto_alg *alg,
 			     struct crypto_dump_info *info)
 {
 	struct sk_buff *in_skb = info->in_skb;
 	struct sk_buff *skb = info->out_skb;
 	struct nlmsghdr *nlh;
 	struct crypto_user_alg *ualg;
 	int err = 0;

 	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, info->nlmsg_seq,
 			CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 	if (!nlh) {
 		err = -EMSGSIZE;
 		goto out;
 	}

 	ualg = nlmsg_data(nlh);

 	err = crypto_report_one(alg, ualg, skb);
 	if (err) {
 		nlmsg_cancel(skb, nlh);
 		goto out;
 	}

 	nlmsg_end(skb, nlh);

 out:
 	return err;
 }

 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 			 struct nlattr **attrs)
 {
 	struct crypto_user_alg *p = nlmsg_data(in_nlh);
 	struct crypto_alg *alg;
 	struct sk_buff *skb;
 	struct crypto_dump_info info;
 	int err;

 	if (!p->cru_driver_name)
 		return -EINVAL;

 	alg = crypto_alg_match(p, 1);
 	if (!alg)
 		return -ENOENT;

 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 	if (!skb)
 		return -ENOMEM;

 	info.in_skb = in_skb;
 	info.out_skb = skb;
 	info.nlmsg_seq = in_nlh->nlmsg_seq;
 	info.nlmsg_flags = 0;

 	err = crypto_report_alg(alg, &info);
 	if (err)
 		return err;

 	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).pid);
 }

 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct crypto_alg *alg;
 	struct crypto_dump_info info;
 	int err;

 	if (cb->args[0])
 		goto out;

 	cb->args[0] = 1;

 	info.in_skb = cb->skb;
 	info.out_skb = skb;
 	info.nlmsg_seq = cb->nlh->nlmsg_seq;
 	info.nlmsg_flags = NLM_F_MULTI;

 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 		err = crypto_report_alg(alg, &info);
 		if (err)
 			goto out_err;
 	}

 out:
 	return skb->len;
 out_err:
 	return err;
 }

 static int crypto_dump_report_done(struct netlink_callback *cb)
 {
 	return 0;
 }

 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 			     struct nlattr **attrs)
 {
 	struct crypto_alg *alg;
 	struct crypto_user_alg *p = nlmsg_data(nlh);
 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 	LIST_HEAD(list);

 	if (priority && !strlen(p->cru_driver_name))
 		return -EINVAL;

 	alg = crypto_alg_match(p, 1);
 	if (!alg)
 		return -ENOENT;

 	down_write(&crypto_alg_sem);

 	crypto_remove_spawns(alg, &list, NULL);

 	if (priority)
 		alg->cra_priority = nla_get_u32(priority);

 	up_write(&crypto_alg_sem);

 	crypto_remove_final(&list);

 	return 0;
 }

 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 			  struct nlattr **attrs)
 {
 	struct crypto_alg *alg;
 	struct crypto_user_alg *p = nlmsg_data(nlh);

 	alg = crypto_alg_match(p, 1);
 	if (!alg)
 		return -ENOENT;

 	/* We can not unregister core algorithms such as aes-generic.
 	 * We would loose the reference in the crypto_alg_list to this algorithm
 	 * if we try to unregister. Unregistering such an algorithm without
 	 * removing the module is not possible, so we restrict to crypto
 	 * instances that are build from templates. */
 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 		return -EINVAL;

 	if (atomic_read(&alg->cra_refcnt) != 1)
 		return -EBUSY;

 	return crypto_unregister_alg(alg);
 }

 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 			  struct nlattr **attrs)
 {
 	int exact;
 	const char *name;
 	struct crypto_alg *alg;
 	struct crypto_user_alg *p = nlmsg_data(nlh);
 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];

 	if (strlen(p->cru_driver_name))
 		exact = 1;

 	if (priority && !exact)
 		return -EINVAL;

 	alg = crypto_alg_match(p, exact);
 	if (alg)
 		return -EEXIST;

 	if (strlen(p->cru_driver_name))
 		name = p->cru_driver_name;
 	else
 		name = p->cru_name;

 	alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 	if (IS_ERR(alg))
 		return PTR_ERR(alg);

 	down_write(&crypto_alg_sem);

 	if (priority)
 		alg->cra_priority = nla_get_u32(priority);

 	up_write(&crypto_alg_sem);

 	crypto_mod_put(alg);

 	return 0;
 }

 #define MSGSIZE(type) sizeof(struct type)

 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 };

 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 	[CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 };

 #undef MSGSIZE

 static struct crypto_link {
 	int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 	int (*dump)(struct sk_buff *, struct netlink_callback *);
 	int (*done)(struct netlink_callback *);
 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = { .doit = crypto_report,
 						       .dump = crypto_dump_report,
 						       .done = crypto_dump_report_done},
 };

 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 	struct crypto_link *link;
 	int type, err;

 	type = nlh->nlmsg_type;
 	if (type > CRYPTO_MSG_MAX)
 		return -EINVAL;

 	type -= CRYPTO_MSG_BASE;
 	link = &crypto_dispatch[type];

 	if (security_netlink_recv(skb, CAP_NET_ADMIN))
 		return -EPERM;

 	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
 		if (link->dump == NULL)
 			return -EINVAL;

 		down_read(&crypto_alg_sem);
 		err = netlink_dump_start(crypto_nlsk, skb, nlh,
 					  link->dump, link->done, 0);
 		up_read(&crypto_alg_sem);

 		return err;
 	}

 	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 			  crypto_policy);
 	if (err < 0)
 		return err;

 	if (link->doit == NULL)
 		return -EINVAL;

 	return link->doit(skb, nlh, attrs);
 }

 static void crypto_netlink_rcv(struct sk_buff *skb)
 {
 	mutex_lock(&crypto_cfg_mutex);
 	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 	mutex_unlock(&crypto_cfg_mutex);
 }

 static int __init crypto_user_init(void)
 {
 	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO,
 					    0, crypto_netlink_rcv,
 					    NULL, THIS_MODULE);
 	if (!crypto_nlsk)
 		return -ENOMEM;

 	return 0;
 }

 static void __exit crypto_user_exit(void)
 {
 	netlink_kernel_release(crypto_nlsk);
 }

 module_init(crypto_user_init);
 module_exit(crypto_user_exit);
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 MODULE_DESCRIPTION("Crypto userspace configuration API");
	/*
	* Crypto user configuration API.
	*
	* Copyright (C) 2011 secunet Security Networks AG
	* Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program; if not, write to the Free Software Foundation, Inc.,
	* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
	*/

	#include <linux/module.h>
	#include <linux/crypto.h>
	#include <linux/cryptouser.h>
	#include <net/netlink.h>
	#include <linux/security.h>
	#include <net/net_namespace.h>
	#include "internal.h"

	DEFINE_MUTEX(crypto_cfg_mutex);

	/* The crypto netlink socket */
	static struct sock *crypto_nlsk;

	struct crypto_dump_info {
	struct sk_buff *in_skb;
	struct sk_buff *out_skb;
	u32 nlmsg_seq;
	u16 nlmsg_flags;
	};

	static struct crypto_alg crypto_alg_match(struct crypto_user_alg p, int exact)
	{
	struct crypto_alg q, alg = NULL;

	down_read(&crypto_alg_sem);

	list_for_each_entry(q, &crypto_alg_list, cra_list) {
	int match = 0;

	if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
	continue;

	if (strlen(p->cru_driver_name))
	match = !strcmp(q->cra_driver_name,
	p->cru_driver_name);
	else if (!exact)
	match = !strcmp(q->cra_name, p->cru_name);

	if (match) {
	alg = q;
	break;
	}
	}

	up_read(&crypto_alg_sem);

	return alg;
	}

	static int crypto_report_cipher(struct sk_buff skb, struct crypto_alg alg)
	{
	struct crypto_report_cipher rcipher;

	strncpy(rcipher.type, "cipher", sizeof(rcipher.type));

	rcipher.blocksize = alg->cra_blocksize;
	rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
	rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;

	NLA_PUT(skb, CRYPTOCFGA_REPORT_CIPHER,
	sizeof(struct crypto_report_cipher), &rcipher);

	return 0;

	nla_put_failure:
	return -EMSGSIZE;
	}

	static int crypto_report_comp(struct sk_buff skb, struct crypto_alg alg)
	{
	struct crypto_report_comp rcomp;

	strncpy(rcomp.type, "compression", sizeof(rcomp.type));
	NLA_PUT(skb, CRYPTOCFGA_REPORT_COMPRESS,
	sizeof(struct crypto_report_comp), &rcomp);

	return 0;

	nla_put_failure:
	return -EMSGSIZE;
	}

	static int crypto_report_one(struct crypto_alg *alg,
	struct crypto_user_alg ualg, struct sk_buff skb)
	{
	strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
	strncpy(ualg->cru_driver_name, alg->cra_driver_name,
	sizeof(ualg->cru_driver_name));
	strncpy(ualg->cru_module_name, module_name(alg->cra_module),
	sizeof(ualg->cru_module_name));

	ualg->cru_type = 0;
	ualg->cru_mask = 0;
	ualg->cru_flags = alg->cra_flags;
	ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);

	NLA_PUT_U32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority);

	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
	struct crypto_report_larval rl;

	strncpy(rl.type, "larval", sizeof(rl.type));
	NLA_PUT(skb, CRYPTOCFGA_REPORT_LARVAL,
	sizeof(struct crypto_report_larval), &rl);

	goto out;
	}

	if (alg->cra_type && alg->cra_type->report) {
	if (alg->cra_type->report(skb, alg))
	goto nla_put_failure;

	goto out;
	}

	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK \| CRYPTO_ALG_LARVAL)) {
	case CRYPTO_ALG_TYPE_CIPHER:
	if (crypto_report_cipher(skb, alg))
	goto nla_put_failure;

	break;
	case CRYPTO_ALG_TYPE_COMPRESS:
	if (crypto_report_comp(skb, alg))
	goto nla_put_failure;

	break;
	}

	out:
	return 0;

	nla_put_failure:
	return -EMSGSIZE;
	}

	static int crypto_report_alg(struct crypto_alg *alg,
	struct crypto_dump_info *info)
	{
	struct sk_buff *in_skb = info->in_skb;
	struct sk_buff *skb = info->out_skb;
	struct nlmsghdr *nlh;
	struct crypto_user_alg *ualg;
	int err = 0;

	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, info->nlmsg_seq,
	CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
	if (!nlh) {
	err = -EMSGSIZE;
	goto out;
	}

	ualg = nlmsg_data(nlh);

	err = crypto_report_one(alg, ualg, skb);
	if (err) {
	nlmsg_cancel(skb, nlh);
	goto out;
	}

	nlmsg_end(skb, nlh);

	out:
	return err;
	}

	static int crypto_report(struct sk_buff in_skb, struct nlmsghdr in_nlh,
	struct nlattr **attrs)
	{
	struct crypto_user_alg *p = nlmsg_data(in_nlh);
	struct crypto_alg *alg;
	struct sk_buff *skb;
	struct crypto_dump_info info;
	int err;

	if (!p->cru_driver_name)
	return -EINVAL;

	alg = crypto_alg_match(p, 1);
	if (!alg)
	return -ENOENT;

	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
	if (!skb)
	return -ENOMEM;

	info.in_skb = in_skb;
	info.out_skb = skb;
	info.nlmsg_seq = in_nlh->nlmsg_seq;
	info.nlmsg_flags = 0;

	err = crypto_report_alg(alg, &info);
	if (err)
	return err;

	return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).pid);
	}

	static int crypto_dump_report(struct sk_buff skb, struct netlink_callback cb)
	{
	struct crypto_alg *alg;
	struct crypto_dump_info info;
	int err;

	if (cb->args[0])
	goto out;

	cb->args[0] = 1;

	info.in_skb = cb->skb;
	info.out_skb = skb;
	info.nlmsg_seq = cb->nlh->nlmsg_seq;
	info.nlmsg_flags = NLM_F_MULTI;

	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
	err = crypto_report_alg(alg, &info);
	if (err)
	goto out_err;
	}

	out:
	return skb->len;
	out_err:
	return err;
	}

	static int crypto_dump_report_done(struct netlink_callback *cb)
	{
	return 0;
	}

	static int crypto_update_alg(struct sk_buff skb, struct nlmsghdr nlh,
	struct nlattr **attrs)
	{
	struct crypto_alg *alg;
	struct crypto_user_alg *p = nlmsg_data(nlh);
	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
	LIST_HEAD(list);

	if (priority && !strlen(p->cru_driver_name))
	return -EINVAL;

	alg = crypto_alg_match(p, 1);
	if (!alg)
	return -ENOENT;

	down_write(&crypto_alg_sem);

	crypto_remove_spawns(alg, &list, NULL);

	if (priority)
	alg->cra_priority = nla_get_u32(priority);

	up_write(&crypto_alg_sem);

	crypto_remove_final(&list);

	return 0;
	}

	static int crypto_del_alg(struct sk_buff skb, struct nlmsghdr nlh,
	struct nlattr **attrs)
	{
	struct crypto_alg *alg;
	struct crypto_user_alg *p = nlmsg_data(nlh);

	alg = crypto_alg_match(p, 1);
	if (!alg)
	return -ENOENT;

	/* We can not unregister core algorithms such as aes-generic.
	* We would loose the reference in the crypto_alg_list to this algorithm
	* if we try to unregister. Unregistering such an algorithm without
	* removing the module is not possible, so we restrict to crypto
	* instances that are build from templates. */
	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
	return -EINVAL;

	if (atomic_read(&alg->cra_refcnt) != 1)
	return -EBUSY;

	return crypto_unregister_alg(alg);
	}

	static int crypto_add_alg(struct sk_buff skb, struct nlmsghdr nlh,
	struct nlattr **attrs)
	{
	int exact;
	const char *name;
	struct crypto_alg *alg;
	struct crypto_user_alg *p = nlmsg_data(nlh);
	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];

	if (strlen(p->cru_driver_name))
	exact = 1;

	if (priority && !exact)
	return -EINVAL;

	alg = crypto_alg_match(p, exact);
	if (alg)
	return -EEXIST;

	if (strlen(p->cru_driver_name))
	name = p->cru_driver_name;
	else
	name = p->cru_name;

	alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
	if (IS_ERR(alg))
	return PTR_ERR(alg);

	down_write(&crypto_alg_sem);

	if (priority)
	alg->cra_priority = nla_get_u32(priority);

	up_write(&crypto_alg_sem);

	crypto_mod_put(alg);

	return 0;
	}

	#define MSGSIZE(type) sizeof(struct type)

	static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
	[CRYPTO_MSG_NEWALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
	[CRYPTO_MSG_DELALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
	[CRYPTO_MSG_UPDATEALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
	[CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
	};

	static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
	[CRYPTOCFGA_PRIORITY_VAL] = { .type = NLA_U32},
	};

	#undef MSGSIZE

	static struct crypto_link {
	int (doit)(struct sk_buff , struct nlmsghdr , struct nlattr *);
	int (dump)(struct sk_buff , struct netlink_callback *);
	int (done)(struct netlink_callback );
	} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
	[CRYPTO_MSG_NEWALG - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
	[CRYPTO_MSG_DELALG - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
	[CRYPTO_MSG_UPDATEALG - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
	[CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE] = { .doit = crypto_report,
	.dump = crypto_dump_report,
	.done = crypto_dump_report_done},
	};

	static int crypto_user_rcv_msg(struct sk_buff skb, struct nlmsghdr nlh)
	{
	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
	struct crypto_link *link;
	int type, err;

	type = nlh->nlmsg_type;
	if (type > CRYPTO_MSG_MAX)
	return -EINVAL;

	type -= CRYPTO_MSG_BASE;
	link = &crypto_dispatch[type];

	if (security_netlink_recv(skb, CAP_NET_ADMIN))
	return -EPERM;

	if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
	(nlh->nlmsg_flags & NLM_F_DUMP))) {
	if (link->dump == NULL)
	return -EINVAL;

	down_read(&crypto_alg_sem);
	err = netlink_dump_start(crypto_nlsk, skb, nlh,
	link->dump, link->done, 0);
	up_read(&crypto_alg_sem);

	return err;
	}

	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
	crypto_policy);
	if (err < 0)
	return err;

	if (link->doit == NULL)
	return -EINVAL;

	return link->doit(skb, nlh, attrs);
	}

	static void crypto_netlink_rcv(struct sk_buff *skb)
	{
	mutex_lock(&crypto_cfg_mutex);
	netlink_rcv_skb(skb, &crypto_user_rcv_msg);
	mutex_unlock(&crypto_cfg_mutex);
	}

	static int __init crypto_user_init(void)
	{
	crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO,
	0, crypto_netlink_rcv,
	NULL, THIS_MODULE);
	if (!crypto_nlsk)
	return -ENOMEM;

	return 0;
	}

	static void __exit crypto_user_exit(void)
	{
	netlink_kernel_release(crypto_nlsk);
	}

	module_init(crypto_user_init);
	module_exit(crypto_user_exit);
	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
	MODULE_DESCRIPTION("Crypto userspace configuration API");