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

 /*
  * algif_hash: User-space interface for hash algorithms
  *
  * This file provides the user-space API for hash algorithms.
  *
  * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
  *
  * 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 <crypto/hash.h>
 #include <crypto/if_alg.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/net.h>
 #include <net/sock.h>

 struct hash_ctx {
 	struct af_alg_sgl sgl;

 	u8 *result;

 	struct af_alg_completion completion;

 	unsigned int len;
 	bool more;

 	struct ahash_request req;
 };

 struct algif_hash_tfm {
 	struct crypto_ahash *hash;
 	bool has_key;
 };

 static int hash_alloc_result(struct sock *sk, struct hash_ctx *ctx)
 {
 	unsigned ds;

 	if (ctx->result)
 		return 0;

 	ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));

 	ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
 	if (!ctx->result)
 		return -ENOMEM;

 	memset(ctx->result, 0, ds);

 	return 0;
 }

 static void hash_free_result(struct sock *sk, struct hash_ctx *ctx)
 {
 	unsigned ds;

 	if (!ctx->result)
 		return;

 	ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));

 	sock_kzfree_s(sk, ctx->result, ds);
 	ctx->result = NULL;
 }

 static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
 			size_t ignored)
 {
 	int limit = ALG_MAX_PAGES * PAGE_SIZE;
 	struct sock *sk = sock->sk;
 	struct alg_sock *ask = alg_sk(sk);
 	struct hash_ctx *ctx = ask->private;
 	long copied = 0;
 	int err;

 	if (limit > sk->sk_sndbuf)
 		limit = sk->sk_sndbuf;

 	lock_sock(sk);
 	if (!ctx->more) {
 		if ((msg->msg_flags & MSG_MORE))
 			hash_free_result(sk, ctx);

 		err = af_alg_wait_for_completion(crypto_ahash_init(&ctx->req),
 						&ctx->completion);
 		if (err)
 			goto unlock;
 	}

 	ctx->more = 0;

 	while (msg_data_left(msg)) {
 		int len = msg_data_left(msg);

 		if (len > limit)
 			len = limit;

 		len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len);
 		if (len < 0) {
 			err = copied ? 0 : len;
 			goto unlock;
 		}

 		ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len);

 		err = af_alg_wait_for_completion(crypto_ahash_update(&ctx->req),
 						 &ctx->completion);
 		af_alg_free_sg(&ctx->sgl);
 		if (err)
 			goto unlock;

 		copied += len;
 		iov_iter_advance(&msg->msg_iter, len);
 	}

 	err = 0;

 	ctx->more = msg->msg_flags & MSG_MORE;
 	if (!ctx->more) {
 		err = hash_alloc_result(sk, ctx);
 		if (err)
 			goto unlock;

 		ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
 		err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
 						 &ctx->completion);
 	}

 unlock:
 	release_sock(sk);

 	return err ?: copied;
 }

 static ssize_t hash_sendpage(struct socket *sock, struct page *page,
 			     int offset, size_t size, int flags)
 {
 	struct sock *sk = sock->sk;
 	struct alg_sock *ask = alg_sk(sk);
 	struct hash_ctx *ctx = ask->private;
 	int err;

 	if (flags & MSG_SENDPAGE_NOTLAST)
 		flags |= MSG_MORE;

 	lock_sock(sk);
 	sg_init_table(ctx->sgl.sg, 1);
 	sg_set_page(ctx->sgl.sg, page, size, offset);

 	if (!(flags & MSG_MORE)) {
 		err = hash_alloc_result(sk, ctx);
 		if (err)
 			goto unlock;
 	} else if (!ctx->more)
 		hash_free_result(sk, ctx);

 	ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);

 	if (!(flags & MSG_MORE)) {
 		if (ctx->more)
 			err = crypto_ahash_finup(&ctx->req);
 		else
 			err = crypto_ahash_digest(&ctx->req);
 	} else {
 		if (!ctx->more) {
 			err = crypto_ahash_init(&ctx->req);
 			err = af_alg_wait_for_completion(err, &ctx->completion);
 			if (err)
 				goto unlock;
 		}

 		err = crypto_ahash_update(&ctx->req);
 	}

 	err = af_alg_wait_for_completion(err, &ctx->completion);
 	if (err)
 		goto unlock;

 	ctx->more = flags & MSG_MORE;

 unlock:
 	release_sock(sk);

 	return err ?: size;
 }

 static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 			int flags)
 {
 	struct sock *sk = sock->sk;
 	struct alg_sock *ask = alg_sk(sk);
 	struct hash_ctx *ctx = ask->private;
 	unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
 	bool result;
 	int err;

 	if (len > ds)
 		len = ds;
 	else if (len < ds)
 		msg->msg_flags |= MSG_TRUNC;

 	lock_sock(sk);
 	result = ctx->result;
 	err = hash_alloc_result(sk, ctx);
 	if (err)
 		goto unlock;

 	ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);

 	if (!result && !ctx->more) {
 		err = af_alg_wait_for_completion(
 				crypto_ahash_init(&ctx->req),
 				&ctx->completion);
 		if (err)
 			goto unlock;
 	}

 	if (!result || ctx->more) {
 		ctx->more = 0;
 		err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
 						 &ctx->completion);
 		if (err)
 			goto unlock;
 	}

 	err = memcpy_to_msg(msg, ctx->result, len);

 unlock:
 	hash_free_result(sk, ctx);
 	release_sock(sk);

 	return err ?: len;
 }

 static int hash_accept(struct socket *sock, struct socket *newsock, int flags,
 		       bool kern)
 {
 	struct sock *sk = sock->sk;
 	struct alg_sock *ask = alg_sk(sk);
 	struct hash_ctx *ctx = ask->private;
 	struct ahash_request *req = &ctx->req;
 	char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req)) ? : 1];
 	struct sock *sk2;
 	struct alg_sock *ask2;
 	struct hash_ctx *ctx2;
 	bool more;
 	int err;

 	lock_sock(sk);
 	more = ctx->more;
 	err = more ? crypto_ahash_export(req, state) : 0;
 	release_sock(sk);

 	if (err)
 		return err;

 	err = af_alg_accept(ask->parent, newsock, kern);
 	if (err)
 		return err;

 	sk2 = newsock->sk;
 	ask2 = alg_sk(sk2);
 	ctx2 = ask2->private;
 	ctx2->more = more;

 	if (!more)
 		return err;

 	err = crypto_ahash_import(&ctx2->req, state);
 	if (err) {
 		sock_orphan(sk2);
 		sock_put(sk2);
 	}

 	return err;
 }

 static struct proto_ops algif_hash_ops = {
 	.family		=	PF_ALG,

 	.connect	=	sock_no_connect,
 	.socketpair	=	sock_no_socketpair,
 	.getname	=	sock_no_getname,
 	.ioctl		=	sock_no_ioctl,
 	.listen		=	sock_no_listen,
 	.shutdown	=	sock_no_shutdown,
 	.getsockopt	=	sock_no_getsockopt,
 	.mmap		=	sock_no_mmap,
 	.bind		=	sock_no_bind,
 	.setsockopt	=	sock_no_setsockopt,
 	.poll		=	sock_no_poll,

 	.release	=	af_alg_release,
 	.sendmsg	=	hash_sendmsg,
 	.sendpage	=	hash_sendpage,
 	.recvmsg	=	hash_recvmsg,
 	.accept		=	hash_accept,
 };

 static int hash_check_key(struct socket *sock)
 {
 	int err = 0;
 	struct sock *psk;
 	struct alg_sock *pask;
 	struct algif_hash_tfm *tfm;
 	struct sock *sk = sock->sk;
 	struct alg_sock *ask = alg_sk(sk);

 	lock_sock(sk);
 	if (ask->refcnt)
 		goto unlock_child;

 	psk = ask->parent;
 	pask = alg_sk(ask->parent);
 	tfm = pask->private;

 	err = -ENOKEY;
 	lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
 	if (!tfm->has_key)
 		goto unlock;

 	if (!pask->refcnt++)
 		sock_hold(psk);

 	ask->refcnt = 1;
 	sock_put(psk);

 	err = 0;

 unlock:
 	release_sock(psk);
 unlock_child:
 	release_sock(sk);

 	return err;
 }

 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
 			      size_t size)
 {
 	int err;

 	err = hash_check_key(sock);
 	if (err)
 		return err;

 	return hash_sendmsg(sock, msg, size);
 }

 static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page,
 				   int offset, size_t size, int flags)
 {
 	int err;

 	err = hash_check_key(sock);
 	if (err)
 		return err;

 	return hash_sendpage(sock, page, offset, size, flags);
 }

 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
 			      size_t ignored, int flags)
 {
 	int err;

 	err = hash_check_key(sock);
 	if (err)
 		return err;

 	return hash_recvmsg(sock, msg, ignored, flags);
 }

 static int hash_accept_nokey(struct socket *sock, struct socket *newsock,
 			     int flags, bool kern)
 {
 	int err;

 	err = hash_check_key(sock);
 	if (err)
 		return err;

 	return hash_accept(sock, newsock, flags, kern);
 }

 static struct proto_ops algif_hash_ops_nokey = {
 	.family		=	PF_ALG,

 	.connect	=	sock_no_connect,
 	.socketpair	=	sock_no_socketpair,
 	.getname	=	sock_no_getname,
 	.ioctl		=	sock_no_ioctl,
 	.listen		=	sock_no_listen,
 	.shutdown	=	sock_no_shutdown,
 	.getsockopt	=	sock_no_getsockopt,
 	.mmap		=	sock_no_mmap,
 	.bind		=	sock_no_bind,
 	.setsockopt	=	sock_no_setsockopt,
 	.poll		=	sock_no_poll,

 	.release	=	af_alg_release,
 	.sendmsg	=	hash_sendmsg_nokey,
 	.sendpage	=	hash_sendpage_nokey,
 	.recvmsg	=	hash_recvmsg_nokey,
 	.accept		=	hash_accept_nokey,
 };

 static void *hash_bind(const char *name, u32 type, u32 mask)
 {
 	struct algif_hash_tfm *tfm;
 	struct crypto_ahash *hash;

 	tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
 	if (!tfm)
 		return ERR_PTR(-ENOMEM);

 	hash = crypto_alloc_ahash(name, type, mask);
 	if (IS_ERR(hash)) {
 		kfree(tfm);
 		return ERR_CAST(hash);
 	}

 	tfm->hash = hash;

 	return tfm;
 }

 static void hash_release(void *private)
 {
 	struct algif_hash_tfm *tfm = private;

 	crypto_free_ahash(tfm->hash);
 	kfree(tfm);
 }

 static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
 {
 	struct algif_hash_tfm *tfm = private;
 	int err;

 	err = crypto_ahash_setkey(tfm->hash, key, keylen);
 	tfm->has_key = !err;

 	return err;
 }

 static void hash_sock_destruct(struct sock *sk)
 {
 	struct alg_sock *ask = alg_sk(sk);
 	struct hash_ctx *ctx = ask->private;

 	hash_free_result(sk, ctx);
 	sock_kfree_s(sk, ctx, ctx->len);
 	af_alg_release_parent(sk);
 }

 static int hash_accept_parent_nokey(void *private, struct sock *sk)
 {
 	struct hash_ctx *ctx;
 	struct alg_sock *ask = alg_sk(sk);
 	struct algif_hash_tfm *tfm = private;
 	struct crypto_ahash *hash = tfm->hash;
 	unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash);

 	ctx = sock_kmalloc(sk, len, GFP_KERNEL);
 	if (!ctx)
 		return -ENOMEM;

 	ctx->result = NULL;
 	ctx->len = len;
 	ctx->more = 0;
 	af_alg_init_completion(&ctx->completion);

 	ask->private = ctx;

 	ahash_request_set_tfm(&ctx->req, hash);
 	ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
 				   af_alg_complete, &ctx->completion);

 	sk->sk_destruct = hash_sock_destruct;

 	return 0;
 }

 static int hash_accept_parent(void *private, struct sock *sk)
 {
 	struct algif_hash_tfm *tfm = private;

 	if (!tfm->has_key && crypto_ahash_has_setkey(tfm->hash))
 		return -ENOKEY;

 	return hash_accept_parent_nokey(private, sk);
 }

 static const struct af_alg_type algif_type_hash = {
 	.bind		=	hash_bind,
 	.release	=	hash_release,
 	.setkey		=	hash_setkey,
 	.accept		=	hash_accept_parent,
 	.accept_nokey	=	hash_accept_parent_nokey,
 	.ops		=	&algif_hash_ops,
 	.ops_nokey	=	&algif_hash_ops_nokey,
 	.name		=	"hash",
 	.owner		=	THIS_MODULE
 };

 static int __init algif_hash_init(void)
 {
 	return af_alg_register_type(&algif_type_hash);
 }

 static void __exit algif_hash_exit(void)
 {
 	int err = af_alg_unregister_type(&algif_type_hash);
 	BUG_ON(err);
 }

 module_init(algif_hash_init);
 module_exit(algif_hash_exit);
 MODULE_LICENSE("GPL");
	/*
	* algif_hash: User-space interface for hash algorithms
	*
	* This file provides the user-space API for hash algorithms.
	*
	* Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
	*
	* 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 <crypto/hash.h>
	#include <crypto/if_alg.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/module.h>
	#include <linux/net.h>
	#include <net/sock.h>

	struct hash_ctx {
	struct af_alg_sgl sgl;

	u8 *result;

	struct af_alg_completion completion;

	unsigned int len;
	bool more;

	struct ahash_request req;
	};

	struct algif_hash_tfm {
	struct crypto_ahash *hash;
	bool has_key;
	};

	static int hash_alloc_result(struct sock sk, struct hash_ctx ctx)
	{
	unsigned ds;

	if (ctx->result)
	return 0;

	ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));

	ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
	if (!ctx->result)
	return -ENOMEM;

	memset(ctx->result, 0, ds);

	return 0;
	}

	static void hash_free_result(struct sock sk, struct hash_ctx ctx)
	{
	unsigned ds;

	if (!ctx->result)
	return;

	ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));

	sock_kzfree_s(sk, ctx->result, ds);
	ctx->result = NULL;
	}

	static int hash_sendmsg(struct socket sock, struct msghdr msg,
	size_t ignored)
	{
	int limit = ALG_MAX_PAGES * PAGE_SIZE;
	struct sock *sk = sock->sk;
	struct alg_sock *ask = alg_sk(sk);
	struct hash_ctx *ctx = ask->private;
	long copied = 0;
	int err;

	if (limit > sk->sk_sndbuf)
	limit = sk->sk_sndbuf;

	lock_sock(sk);
	if (!ctx->more) {
	if ((msg->msg_flags & MSG_MORE))
	hash_free_result(sk, ctx);

	err = af_alg_wait_for_completion(crypto_ahash_init(&ctx->req),
	&ctx->completion);
	if (err)
	goto unlock;
	}

	ctx->more = 0;

	while (msg_data_left(msg)) {
	int len = msg_data_left(msg);

	if (len > limit)
	len = limit;

	len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len);
	if (len < 0) {
	err = copied ? 0 : len;
	goto unlock;
	}

	ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len);

	err = af_alg_wait_for_completion(crypto_ahash_update(&ctx->req),
	&ctx->completion);
	af_alg_free_sg(&ctx->sgl);
	if (err)
	goto unlock;

	copied += len;
	iov_iter_advance(&msg->msg_iter, len);
	}

	err = 0;

	ctx->more = msg->msg_flags & MSG_MORE;
	if (!ctx->more) {
	err = hash_alloc_result(sk, ctx);
	if (err)
	goto unlock;

	ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
	err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
	&ctx->completion);
	}

	unlock:
	release_sock(sk);

	return err ?: copied;
	}

	static ssize_t hash_sendpage(struct socket sock, struct page page,
	int offset, size_t size, int flags)
	{
	struct sock *sk = sock->sk;
	struct alg_sock *ask = alg_sk(sk);
	struct hash_ctx *ctx = ask->private;
	int err;

	if (flags & MSG_SENDPAGE_NOTLAST)
	flags \|= MSG_MORE;

	lock_sock(sk);
	sg_init_table(ctx->sgl.sg, 1);
	sg_set_page(ctx->sgl.sg, page, size, offset);

	if (!(flags & MSG_MORE)) {
	err = hash_alloc_result(sk, ctx);
	if (err)
	goto unlock;
	} else if (!ctx->more)
	hash_free_result(sk, ctx);

	ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);

	if (!(flags & MSG_MORE)) {
	if (ctx->more)
	err = crypto_ahash_finup(&ctx->req);
	else
	err = crypto_ahash_digest(&ctx->req);
	} else {
	if (!ctx->more) {
	err = crypto_ahash_init(&ctx->req);
	err = af_alg_wait_for_completion(err, &ctx->completion);
	if (err)
	goto unlock;
	}

	err = crypto_ahash_update(&ctx->req);
	}

	err = af_alg_wait_for_completion(err, &ctx->completion);
	if (err)
	goto unlock;

	ctx->more = flags & MSG_MORE;

	unlock:
	release_sock(sk);

	return err ?: size;
	}

	static int hash_recvmsg(struct socket sock, struct msghdr msg, size_t len,
	int flags)
	{
	struct sock *sk = sock->sk;
	struct alg_sock *ask = alg_sk(sk);
	struct hash_ctx *ctx = ask->private;
	unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
	bool result;
	int err;

	if (len > ds)
	len = ds;
	else if (len < ds)
	msg->msg_flags \|= MSG_TRUNC;

	lock_sock(sk);
	result = ctx->result;
	err = hash_alloc_result(sk, ctx);
	if (err)
	goto unlock;

	ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);

	if (!result && !ctx->more) {
	err = af_alg_wait_for_completion(
	crypto_ahash_init(&ctx->req),
	&ctx->completion);
	if (err)
	goto unlock;
	}

	if (!result \|\| ctx->more) {
	ctx->more = 0;
	err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
	&ctx->completion);
	if (err)
	goto unlock;
	}

	err = memcpy_to_msg(msg, ctx->result, len);

	unlock:
	hash_free_result(sk, ctx);
	release_sock(sk);

	return err ?: len;
	}

	static int hash_accept(struct socket sock, struct socket newsock, int flags,
	bool kern)
	{
	struct sock *sk = sock->sk;
	struct alg_sock *ask = alg_sk(sk);
	struct hash_ctx *ctx = ask->private;
	struct ahash_request *req = &ctx->req;
	char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req)) ? : 1];
	struct sock *sk2;
	struct alg_sock *ask2;
	struct hash_ctx *ctx2;
	bool more;
	int err;

	lock_sock(sk);
	more = ctx->more;
	err = more ? crypto_ahash_export(req, state) : 0;
	release_sock(sk);

	if (err)
	return err;

	err = af_alg_accept(ask->parent, newsock, kern);
	if (err)
	return err;

	sk2 = newsock->sk;
	ask2 = alg_sk(sk2);
	ctx2 = ask2->private;
	ctx2->more = more;

	if (!more)
	return err;

	err = crypto_ahash_import(&ctx2->req, state);
	if (err) {
	sock_orphan(sk2);
	sock_put(sk2);
	}

	return err;
	}

	static struct proto_ops algif_hash_ops = {
	.family = PF_ALG,

	.connect = sock_no_connect,
	.socketpair = sock_no_socketpair,
	.getname = sock_no_getname,
	.ioctl = sock_no_ioctl,
	.listen = sock_no_listen,
	.shutdown = sock_no_shutdown,
	.getsockopt = sock_no_getsockopt,
	.mmap = sock_no_mmap,
	.bind = sock_no_bind,
	.setsockopt = sock_no_setsockopt,
	.poll = sock_no_poll,

	.release = af_alg_release,
	.sendmsg = hash_sendmsg,
	.sendpage = hash_sendpage,
	.recvmsg = hash_recvmsg,
	.accept = hash_accept,
	};

	static int hash_check_key(struct socket *sock)
	{
	int err = 0;
	struct sock *psk;
	struct alg_sock *pask;
	struct algif_hash_tfm *tfm;
	struct sock *sk = sock->sk;
	struct alg_sock *ask = alg_sk(sk);

	lock_sock(sk);
	if (ask->refcnt)
	goto unlock_child;

	psk = ask->parent;
	pask = alg_sk(ask->parent);
	tfm = pask->private;

	err = -ENOKEY;
	lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
	if (!tfm->has_key)
	goto unlock;

	if (!pask->refcnt++)
	sock_hold(psk);

	ask->refcnt = 1;
	sock_put(psk);

	err = 0;

	unlock:
	release_sock(psk);
	unlock_child:
	release_sock(sk);

	return err;
	}

	static int hash_sendmsg_nokey(struct socket sock, struct msghdr msg,
	size_t size)
	{
	int err;

	err = hash_check_key(sock);
	if (err)
	return err;

	return hash_sendmsg(sock, msg, size);
	}

	static ssize_t hash_sendpage_nokey(struct socket sock, struct page page,
	int offset, size_t size, int flags)
	{
	int err;

	err = hash_check_key(sock);
	if (err)
	return err;

	return hash_sendpage(sock, page, offset, size, flags);
	}

	static int hash_recvmsg_nokey(struct socket sock, struct msghdr msg,
	size_t ignored, int flags)
	{
	int err;

	err = hash_check_key(sock);
	if (err)
	return err;

	return hash_recvmsg(sock, msg, ignored, flags);
	}

	static int hash_accept_nokey(struct socket sock, struct socket newsock,
	int flags, bool kern)
	{
	int err;

	err = hash_check_key(sock);
	if (err)
	return err;

	return hash_accept(sock, newsock, flags, kern);
	}

	static struct proto_ops algif_hash_ops_nokey = {
	.family = PF_ALG,

	.connect = sock_no_connect,
	.socketpair = sock_no_socketpair,
	.getname = sock_no_getname,
	.ioctl = sock_no_ioctl,
	.listen = sock_no_listen,
	.shutdown = sock_no_shutdown,
	.getsockopt = sock_no_getsockopt,
	.mmap = sock_no_mmap,
	.bind = sock_no_bind,
	.setsockopt = sock_no_setsockopt,
	.poll = sock_no_poll,

	.release = af_alg_release,
	.sendmsg = hash_sendmsg_nokey,
	.sendpage = hash_sendpage_nokey,
	.recvmsg = hash_recvmsg_nokey,
	.accept = hash_accept_nokey,
	};

	static void hash_bind(const char name, u32 type, u32 mask)
	{
	struct algif_hash_tfm *tfm;
	struct crypto_ahash *hash;

	tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
	if (!tfm)
	return ERR_PTR(-ENOMEM);

	hash = crypto_alloc_ahash(name, type, mask);
	if (IS_ERR(hash)) {
	kfree(tfm);
	return ERR_CAST(hash);
	}

	tfm->hash = hash;

	return tfm;
	}

	static void hash_release(void *private)
	{
	struct algif_hash_tfm *tfm = private;

	crypto_free_ahash(tfm->hash);
	kfree(tfm);
	}

	static int hash_setkey(void private, const u8 key, unsigned int keylen)
	{
	struct algif_hash_tfm *tfm = private;
	int err;

	err = crypto_ahash_setkey(tfm->hash, key, keylen);
	tfm->has_key = !err;

	return err;
	}

	static void hash_sock_destruct(struct sock *sk)
	{
	struct alg_sock *ask = alg_sk(sk);
	struct hash_ctx *ctx = ask->private;

	hash_free_result(sk, ctx);
	sock_kfree_s(sk, ctx, ctx->len);
	af_alg_release_parent(sk);
	}

	static int hash_accept_parent_nokey(void private, struct sock sk)
	{
	struct hash_ctx *ctx;
	struct alg_sock *ask = alg_sk(sk);
	struct algif_hash_tfm *tfm = private;
	struct crypto_ahash *hash = tfm->hash;
	unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash);

	ctx = sock_kmalloc(sk, len, GFP_KERNEL);
	if (!ctx)
	return -ENOMEM;

	ctx->result = NULL;
	ctx->len = len;
	ctx->more = 0;
	af_alg_init_completion(&ctx->completion);

	ask->private = ctx;

	ahash_request_set_tfm(&ctx->req, hash);
	ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
	af_alg_complete, &ctx->completion);

	sk->sk_destruct = hash_sock_destruct;

	return 0;
	}

	static int hash_accept_parent(void private, struct sock sk)
	{
	struct algif_hash_tfm *tfm = private;

	if (!tfm->has_key && crypto_ahash_has_setkey(tfm->hash))
	return -ENOKEY;

	return hash_accept_parent_nokey(private, sk);
	}

	static const struct af_alg_type algif_type_hash = {
	.bind = hash_bind,
	.release = hash_release,
	.setkey = hash_setkey,
	.accept = hash_accept_parent,
	.accept_nokey = hash_accept_parent_nokey,
	.ops = &algif_hash_ops,
	.ops_nokey = &algif_hash_ops_nokey,
	.name = "hash",
	.owner = THIS_MODULE
	};

	static int __init algif_hash_init(void)
	{
	return af_alg_register_type(&algif_type_hash);
	}

	static void __exit algif_hash_exit(void)
	{
	int err = af_alg_unregister_type(&algif_type_hash);
	BUG_ON(err);
	}

	module_init(algif_hash_init);
	module_exit(algif_hash_exit);
	MODULE_LICENSE("GPL");