crypto/crypto_user_base.c - kernel/msm-5.4 - Gitiles

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Crypto user configuration API.
  *
  * Copyright (C) 2011 secunet Security Networks AG
  * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
  */

 #include <linux/module.h>
 #include <linux/crypto.h>
 #include <linux/cryptouser.h>
 #include <linux/sched.h>
 #include <linux/security.h>
 #include <net/netlink.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/internal/rng.h>
 #include <crypto/akcipher.h>
 #include <crypto/kpp.h>
 #include <crypto/internal/cryptouser.h>

 #include "internal.h"

 #define null_terminated(x)	(strnlen(x, sizeof(x)) < sizeof(x))

 static DEFINE_MUTEX(crypto_cfg_mutex);

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

 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 (crypto_is_larval(q))
 			continue;

 		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)
 			continue;

 		if (unlikely(!crypto_mod_get(q)))
 			continue;

 		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;

 	memset(&rcipher, 0, sizeof(rcipher));

 	strscpy(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;

 	return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
 		       sizeof(rcipher), &rcipher);
 }

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

 	memset(&rcomp, 0, sizeof(rcomp));

 	strscpy(rcomp.type, "compression", sizeof(rcomp.type));

 	return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
 }

 static int crypto_report_one(struct crypto_alg *alg,
 			     struct crypto_user_alg *ualg, struct sk_buff *skb)
 {
 	memset(ualg, 0, sizeof(*ualg));

 	strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 	strscpy(ualg->cru_driver_name, alg->cra_driver_name,
 		sizeof(ualg->cru_driver_name));
 	strscpy(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 = refcount_read(&alg->cra_refcnt);

 	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 		goto nla_put_failure;
 	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 		struct crypto_report_larval rl;

 		memset(&rl, 0, sizeof(rl));
 		strscpy(rl.type, "larval", sizeof(rl.type));
 		if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
 			goto nla_put_failure;
 		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).portid, 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 net *net = sock_net(in_skb->sk);
 	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 (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 		return -EINVAL;

 	alg = crypto_alg_match(p, 0);
 	if (!alg)
 		return -ENOENT;

 	err = -ENOMEM;
 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (!skb)
 		goto drop_alg;

 	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);

 drop_alg:
 	crypto_mod_put(alg);

 	if (err)
 		return err;

 	return nlmsg_unicast(net->crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 }

 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	const size_t start_pos = cb->args[0];
 	size_t pos = 0;
 	struct crypto_dump_info info;
 	struct crypto_alg *alg;
 	int res;

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

 	down_read(&crypto_alg_sem);
 	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 		if (pos >= start_pos) {
 			res = crypto_report_alg(alg, &info);
 			if (res == -EMSGSIZE)
 				break;
 			if (res)
 				goto out;
 		}
 		pos++;
 	}
 	cb->args[0] = pos;
 	res = skb->len;
 out:
 	up_read(&crypto_alg_sem);
 	return res;
 }

 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 (!netlink_capable(skb, CAP_NET_ADMIN))
 		return -EPERM;

 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 		return -EINVAL;

 	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_mod_put(alg);
 	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);
 	int err;

 	if (!netlink_capable(skb, CAP_NET_ADMIN))
 		return -EPERM;

 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 		return -EINVAL;

 	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. */
 	err = -EINVAL;
 	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 		goto drop_alg;

 	err = -EBUSY;
 	if (refcount_read(&alg->cra_refcnt) > 2)
 		goto drop_alg;

 	err = crypto_unregister_instance((struct crypto_instance *)alg);

 drop_alg:
 	crypto_mod_put(alg);
 	return err;
 }

 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 			  struct nlattr **attrs)
 {
 	int exact = 0;
 	const char *name;
 	struct crypto_alg *alg;
 	struct crypto_user_alg *p = nlmsg_data(nlh);
 	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];

 	if (!netlink_capable(skb, CAP_NET_ADMIN))
 		return -EPERM;

 	if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 		return -EINVAL;

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

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

 	alg = crypto_alg_match(p, exact);
 	if (alg) {
 		crypto_mod_put(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;
 }

 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 			  struct nlattr **attrs)
 {
 	if (!netlink_capable(skb, CAP_NET_ADMIN))
 		return -EPERM;
 	return crypto_del_default_rng();
 }

 #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),
 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = 0,
 	[CRYPTO_MSG_GETSTAT	- 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 const 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},
 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 	[CRYPTO_MSG_GETSTAT	- CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
 };

 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 			       struct netlink_ext_ack *extack)
 {
 	struct net *net = sock_net(skb->sk);
 	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 	const 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 ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 	    (nlh->nlmsg_flags & NLM_F_DUMP))) {
 		struct crypto_alg *alg;
 		unsigned long dump_alloc = 0;

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

 		down_read(&crypto_alg_sem);
 		list_for_each_entry(alg, &crypto_alg_list, cra_list)
 			dump_alloc += CRYPTO_REPORT_MAXSIZE;
 		up_read(&crypto_alg_sem);

 		{
 			struct netlink_dump_control c = {
 				.dump = link->dump,
 				.done = link->done,
 				.min_dump_alloc = min(dump_alloc, 65535UL),
 			};
 			err = netlink_dump_start(net->crypto_nlsk, skb, nlh, &c);
 		}

 		return err;
 	}

 	err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
 				     CRYPTOCFGA_MAX, crypto_policy, extack);
 	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 __net_init crypto_netlink_init(struct net *net)
 {
 	struct netlink_kernel_cfg cfg = {
 		.input	= crypto_netlink_rcv,
 	};

 	net->crypto_nlsk = netlink_kernel_create(net, NETLINK_CRYPTO, &cfg);
 	return net->crypto_nlsk == NULL ? -ENOMEM : 0;
 }

 static void __net_exit crypto_netlink_exit(struct net *net)
 {
 	netlink_kernel_release(net->crypto_nlsk);
 	net->crypto_nlsk = NULL;
 }

 static struct pernet_operations crypto_netlink_net_ops = {
 	.init = crypto_netlink_init,
 	.exit = crypto_netlink_exit,
 };

 static int __init crypto_user_init(void)
 {
 	return register_pernet_subsys(&crypto_netlink_net_ops);
 }

 static void __exit crypto_user_exit(void)
 {
 	unregister_pernet_subsys(&crypto_netlink_net_ops);
 }

 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");
 MODULE_ALIAS("net-pf-16-proto-21");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Crypto user configuration API.
	*
	* Copyright (C) 2011 secunet Security Networks AG
	* Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
	*/

	#include <linux/module.h>
	#include <linux/crypto.h>
	#include <linux/cryptouser.h>
	#include <linux/sched.h>
	#include <linux/security.h>
	#include <net/netlink.h>
	#include <net/net_namespace.h>
	#include <net/sock.h>
	#include <crypto/internal/skcipher.h>
	#include <crypto/internal/rng.h>
	#include <crypto/akcipher.h>
	#include <crypto/kpp.h>
	#include <crypto/internal/cryptouser.h>

	#include "internal.h"

	#define null_terminated(x) (strnlen(x, sizeof(x)) < sizeof(x))

	static DEFINE_MUTEX(crypto_cfg_mutex);

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

	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 (crypto_is_larval(q))
	continue;

	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)
	continue;

	if (unlikely(!crypto_mod_get(q)))
	continue;

	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;

	memset(&rcipher, 0, sizeof(rcipher));

	strscpy(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;

	return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
	sizeof(rcipher), &rcipher);
	}

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

	memset(&rcomp, 0, sizeof(rcomp));

	strscpy(rcomp.type, "compression", sizeof(rcomp.type));

	return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
	}

	static int crypto_report_one(struct crypto_alg *alg,
	struct crypto_user_alg ualg, struct sk_buff skb)
	{
	memset(ualg, 0, sizeof(*ualg));

	strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
	strscpy(ualg->cru_driver_name, alg->cra_driver_name,
	sizeof(ualg->cru_driver_name));
	strscpy(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 = refcount_read(&alg->cra_refcnt);

	if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
	goto nla_put_failure;
	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
	struct crypto_report_larval rl;

	memset(&rl, 0, sizeof(rl));
	strscpy(rl.type, "larval", sizeof(rl.type));
	if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
	goto nla_put_failure;
	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).portid, 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 net *net = sock_net(in_skb->sk);
	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 (!null_terminated(p->cru_name) \|\| !null_terminated(p->cru_driver_name))
	return -EINVAL;

	alg = crypto_alg_match(p, 0);
	if (!alg)
	return -ENOENT;

	err = -ENOMEM;
	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (!skb)
	goto drop_alg;

	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);

	drop_alg:
	crypto_mod_put(alg);

	if (err)
	return err;

	return nlmsg_unicast(net->crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
	}

	static int crypto_dump_report(struct sk_buff skb, struct netlink_callback cb)
	{
	const size_t start_pos = cb->args[0];
	size_t pos = 0;
	struct crypto_dump_info info;
	struct crypto_alg *alg;
	int res;

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

	down_read(&crypto_alg_sem);
	list_for_each_entry(alg, &crypto_alg_list, cra_list) {
	if (pos >= start_pos) {
	res = crypto_report_alg(alg, &info);
	if (res == -EMSGSIZE)
	break;
	if (res)
	goto out;
	}
	pos++;
	}
	cb->args[0] = pos;
	res = skb->len;
	out:
	up_read(&crypto_alg_sem);
	return res;
	}

	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 (!netlink_capable(skb, CAP_NET_ADMIN))
	return -EPERM;

	if (!null_terminated(p->cru_name) \|\| !null_terminated(p->cru_driver_name))
	return -EINVAL;

	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_mod_put(alg);
	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);
	int err;

	if (!netlink_capable(skb, CAP_NET_ADMIN))
	return -EPERM;

	if (!null_terminated(p->cru_name) \|\| !null_terminated(p->cru_driver_name))
	return -EINVAL;

	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. */
	err = -EINVAL;
	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
	goto drop_alg;

	err = -EBUSY;
	if (refcount_read(&alg->cra_refcnt) > 2)
	goto drop_alg;

	err = crypto_unregister_instance((struct crypto_instance *)alg);

	drop_alg:
	crypto_mod_put(alg);
	return err;
	}

	static int crypto_add_alg(struct sk_buff skb, struct nlmsghdr nlh,
	struct nlattr **attrs)
	{
	int exact = 0;
	const char *name;
	struct crypto_alg *alg;
	struct crypto_user_alg *p = nlmsg_data(nlh);
	struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];

	if (!netlink_capable(skb, CAP_NET_ADMIN))
	return -EPERM;

	if (!null_terminated(p->cru_name) \|\| !null_terminated(p->cru_driver_name))
	return -EINVAL;

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

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

	alg = crypto_alg_match(p, exact);
	if (alg) {
	crypto_mod_put(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;
	}

	static int crypto_del_rng(struct sk_buff skb, struct nlmsghdr nlh,
	struct nlattr **attrs)
	{
	if (!netlink_capable(skb, CAP_NET_ADMIN))
	return -EPERM;
	return crypto_del_default_rng();
	}

	#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),
	[CRYPTO_MSG_DELRNG - CRYPTO_MSG_BASE] = 0,
	[CRYPTO_MSG_GETSTAT - 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 const 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},
	[CRYPTO_MSG_DELRNG - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
	[CRYPTO_MSG_GETSTAT - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
	};

	static int crypto_user_rcv_msg(struct sk_buff skb, struct nlmsghdr nlh,
	struct netlink_ext_ack *extack)
	{
	struct net *net = sock_net(skb->sk);
	struct nlattr *attrs[CRYPTOCFGA_MAX+1];
	const 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 ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
	(nlh->nlmsg_flags & NLM_F_DUMP))) {
	struct crypto_alg *alg;
	unsigned long dump_alloc = 0;

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

	down_read(&crypto_alg_sem);
	list_for_each_entry(alg, &crypto_alg_list, cra_list)
	dump_alloc += CRYPTO_REPORT_MAXSIZE;
	up_read(&crypto_alg_sem);

	{
	struct netlink_dump_control c = {
	.dump = link->dump,
	.done = link->done,
	.min_dump_alloc = min(dump_alloc, 65535UL),
	};
	err = netlink_dump_start(net->crypto_nlsk, skb, nlh, &c);
	}

	return err;
	}

	err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
	CRYPTOCFGA_MAX, crypto_policy, extack);
	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 __net_init crypto_netlink_init(struct net *net)
	{
	struct netlink_kernel_cfg cfg = {
	.input = crypto_netlink_rcv,
	};

	net->crypto_nlsk = netlink_kernel_create(net, NETLINK_CRYPTO, &cfg);
	return net->crypto_nlsk == NULL ? -ENOMEM : 0;
	}

	static void __net_exit crypto_netlink_exit(struct net *net)
	{
	netlink_kernel_release(net->crypto_nlsk);
	net->crypto_nlsk = NULL;
	}

	static struct pernet_operations crypto_netlink_net_ops = {
	.init = crypto_netlink_init,
	.exit = crypto_netlink_exit,
	};

	static int __init crypto_user_init(void)
	{
	return register_pernet_subsys(&crypto_netlink_net_ops);
	}

	static void __exit crypto_user_exit(void)
	{
	unregister_pernet_subsys(&crypto_netlink_net_ops);
	}

	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");
	MODULE_ALIAS("net-pf-16-proto-21");