/*
   * algif_aead: User-space interface for AEAD algorithms
   *
   * Copyright (C) 2014, Stephan Mueller <smueller@chronox.de>
   *
   * This file provides the user-space API for AEAD ciphers.
   *
   * This file is derived from algif_skcipher.c.
   *
   * 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/internal/aead.h>

  #include <crypto/scatterwalk.h>
  #include <crypto/if_alg.h>
  #include <linux/init.h>
  #include <linux/list.h>
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/module.h>
  #include <linux/net.h>
  #include <net/sock.h>
  
  struct aead_sg_list {
  	unsigned int cur;
  	struct scatterlist sg[ALG_MAX_PAGES];
  };

  struct aead_async_rsgl {
  	struct af_alg_sgl sgl;
  	struct list_head list;
  };
  
  struct aead_async_req {
  	struct scatterlist *tsgl;
  	struct aead_async_rsgl first_rsgl;
  	struct list_head list;
  	struct kiocb *iocb;
  	unsigned int tsgls;
  	char iv[];
  };

  struct aead_ctx {
  	struct aead_sg_list tsgl;

  	struct aead_async_rsgl first_rsgl;
  	struct list_head list;

  
  	void *iv;
  
  	struct af_alg_completion completion;
  
  	unsigned long used;
  
  	unsigned int len;
  	bool more;
  	bool merge;
  	bool enc;
  
  	size_t aead_assoclen;
  	struct aead_request aead_req;
  };
  
  static inline int aead_sndbuf(struct sock *sk)
  {
  	struct alg_sock *ask = alg_sk(sk);
  	struct aead_ctx *ctx = ask->private;
  
  	return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
  			  ctx->used, 0);
  }
  
  static inline bool aead_writable(struct sock *sk)
  {
  	return PAGE_SIZE <= aead_sndbuf(sk);
  }
  
  static inline bool aead_sufficient_data(struct aead_ctx *ctx)
  {
  	unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));

  	return ctx->used >= ctx->aead_assoclen + as;

  }

  static void aead_reset_ctx(struct aead_ctx *ctx)
  {
  	struct aead_sg_list *sgl = &ctx->tsgl;
  
  	sg_init_table(sgl->sg, ALG_MAX_PAGES);
  	sgl->cur = 0;
  	ctx->used = 0;
  	ctx->more = 0;
  	ctx->merge = 0;
  }

  static void aead_put_sgl(struct sock *sk)
  {
  	struct alg_sock *ask = alg_sk(sk);
  	struct aead_ctx *ctx = ask->private;
  	struct aead_sg_list *sgl = &ctx->tsgl;
  	struct scatterlist *sg = sgl->sg;
  	unsigned int i;
  
  	for (i = 0; i < sgl->cur; i++) {
  		if (!sg_page(sg + i))
  			continue;
  
  		put_page(sg_page(sg + i));
  		sg_assign_page(sg + i, NULL);
  	}

  	aead_reset_ctx(ctx);

  }
  
  static void aead_wmem_wakeup(struct sock *sk)
  {
  	struct socket_wq *wq;
  
  	if (!aead_writable(sk))
  		return;
  
  	rcu_read_lock();
  	wq = rcu_dereference(sk->sk_wq);

  	if (skwq_has_sleeper(wq))

  		wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
  							   POLLRDNORM |
  							   POLLRDBAND);
  	sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
  	rcu_read_unlock();
  }
  
  static int aead_wait_for_data(struct sock *sk, unsigned flags)
  {
  	struct alg_sock *ask = alg_sk(sk);
  	struct aead_ctx *ctx = ask->private;
  	long timeout;
  	DEFINE_WAIT(wait);
  	int err = -ERESTARTSYS;
  
  	if (flags & MSG_DONTWAIT)
  		return -EAGAIN;

  	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);

  
  	for (;;) {
  		if (signal_pending(current))
  			break;
  		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
  		timeout = MAX_SCHEDULE_TIMEOUT;
  		if (sk_wait_event(sk, &timeout, !ctx->more)) {
  			err = 0;
  			break;
  		}
  	}
  	finish_wait(sk_sleep(sk), &wait);

  	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);

  
  	return err;
  }
  
  static void aead_data_wakeup(struct sock *sk)
  {
  	struct alg_sock *ask = alg_sk(sk);
  	struct aead_ctx *ctx = ask->private;
  	struct socket_wq *wq;
  
  	if (ctx->more)
  		return;
  	if (!ctx->used)
  		return;
  
  	rcu_read_lock();
  	wq = rcu_dereference(sk->sk_wq);

  	if (skwq_has_sleeper(wq))

  		wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
  							   POLLRDNORM |
  							   POLLRDBAND);
  	sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
  	rcu_read_unlock();
  }

  static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)

  {
  	struct sock *sk = sock->sk;
  	struct alg_sock *ask = alg_sk(sk);
  	struct aead_ctx *ctx = ask->private;
  	unsigned ivsize =
  		crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req));
  	struct aead_sg_list *sgl = &ctx->tsgl;
  	struct af_alg_control con = {};
  	long copied = 0;
  	bool enc = 0;
  	bool init = 0;
  	int err = -EINVAL;
  
  	if (msg->msg_controllen) {
  		err = af_alg_cmsg_send(msg, &con);
  		if (err)
  			return err;
  
  		init = 1;
  		switch (con.op) {
  		case ALG_OP_ENCRYPT:
  			enc = 1;
  			break;
  		case ALG_OP_DECRYPT:
  			enc = 0;
  			break;
  		default:
  			return -EINVAL;
  		}
  
  		if (con.iv && con.iv->ivlen != ivsize)
  			return -EINVAL;
  	}
  
  	lock_sock(sk);
  	if (!ctx->more && ctx->used)
  		goto unlock;
  
  	if (init) {
  		ctx->enc = enc;
  		if (con.iv)
  			memcpy(ctx->iv, con.iv->iv, ivsize);
  
  		ctx->aead_assoclen = con.aead_assoclen;
  	}
  
  	while (size) {

  		size_t len = size;

  		struct scatterlist *sg = NULL;
  
  		/* use the existing memory in an allocated page */
  		if (ctx->merge) {
  			sg = sgl->sg + sgl->cur - 1;
  			len = min_t(unsigned long, len,
  				    PAGE_SIZE - sg->offset - sg->length);
  			err = memcpy_from_msg(page_address(sg_page(sg)) +
  					      sg->offset + sg->length,
  					      msg, len);
  			if (err)
  				goto unlock;
  
  			sg->length += len;
  			ctx->merge = (sg->offset + sg->length) &
  				     (PAGE_SIZE - 1);
  
  			ctx->used += len;
  			copied += len;
  			size -= len;
  			continue;
  		}
  
  		if (!aead_writable(sk)) {
  			/* user space sent too much data */
  			aead_put_sgl(sk);
  			err = -EMSGSIZE;
  			goto unlock;
  		}
  
  		/* allocate a new page */
  		len = min_t(unsigned long, size, aead_sndbuf(sk));
  		while (len) {

  			size_t plen = 0;

  
  			if (sgl->cur >= ALG_MAX_PAGES) {
  				aead_put_sgl(sk);
  				err = -E2BIG;
  				goto unlock;
  			}
  
  			sg = sgl->sg + sgl->cur;

  			plen = min_t(size_t, len, PAGE_SIZE);

  
  			sg_assign_page(sg, alloc_page(GFP_KERNEL));
  			err = -ENOMEM;
  			if (!sg_page(sg))
  				goto unlock;
  
  			err = memcpy_from_msg(page_address(sg_page(sg)),
  					      msg, plen);
  			if (err) {
  				__free_page(sg_page(sg));
  				sg_assign_page(sg, NULL);
  				goto unlock;
  			}
  
  			sg->offset = 0;
  			sg->length = plen;
  			len -= plen;
  			ctx->used += plen;
  			copied += plen;
  			sgl->cur++;
  			size -= plen;
  			ctx->merge = plen & (PAGE_SIZE - 1);
  		}
  	}
  
  	err = 0;
  
  	ctx->more = msg->msg_flags & MSG_MORE;
  	if (!ctx->more && !aead_sufficient_data(ctx)) {
  		aead_put_sgl(sk);
  		err = -EMSGSIZE;
  	}
  
  unlock:
  	aead_data_wakeup(sk);
  	release_sock(sk);
  
  	return err ?: copied;
  }
  
  static ssize_t aead_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 aead_ctx *ctx = ask->private;
  	struct aead_sg_list *sgl = &ctx->tsgl;
  	int err = -EINVAL;
  
  	if (flags & MSG_SENDPAGE_NOTLAST)
  		flags |= MSG_MORE;
  
  	if (sgl->cur >= ALG_MAX_PAGES)
  		return -E2BIG;
  
  	lock_sock(sk);
  	if (!ctx->more && ctx->used)
  		goto unlock;
  
  	if (!size)
  		goto done;
  
  	if (!aead_writable(sk)) {
  		/* user space sent too much data */
  		aead_put_sgl(sk);
  		err = -EMSGSIZE;
  		goto unlock;
  	}
  
  	ctx->merge = 0;
  
  	get_page(page);
  	sg_set_page(sgl->sg + sgl->cur, page, size, offset);
  	sgl->cur++;
  	ctx->used += size;
  
  	err = 0;
  
  done:
  	ctx->more = flags & MSG_MORE;
  	if (!ctx->more && !aead_sufficient_data(ctx)) {
  		aead_put_sgl(sk);
  		err = -EMSGSIZE;
  	}
  
  unlock:
  	aead_data_wakeup(sk);
  	release_sock(sk);
  
  	return err ?: size;
  }

  #define GET_ASYM_REQ(req, tfm) (struct aead_async_req *) \
  		((char *)req + sizeof(struct aead_request) + \
  		 crypto_aead_reqsize(tfm))
  
   #define GET_REQ_SIZE(tfm) sizeof(struct aead_async_req) + \
  	crypto_aead_reqsize(tfm) + crypto_aead_ivsize(tfm) + \
  	sizeof(struct aead_request)
  
  static void aead_async_cb(struct crypto_async_request *_req, int err)
  {
  	struct sock *sk = _req->data;
  	struct alg_sock *ask = alg_sk(sk);
  	struct aead_ctx *ctx = ask->private;
  	struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
  	struct aead_request *req = aead_request_cast(_req);
  	struct aead_async_req *areq = GET_ASYM_REQ(req, tfm);
  	struct scatterlist *sg = areq->tsgl;
  	struct aead_async_rsgl *rsgl;
  	struct kiocb *iocb = areq->iocb;
  	unsigned int i, reqlen = GET_REQ_SIZE(tfm);
  
  	list_for_each_entry(rsgl, &areq->list, list) {
  		af_alg_free_sg(&rsgl->sgl);
  		if (rsgl != &areq->first_rsgl)
  			sock_kfree_s(sk, rsgl, sizeof(*rsgl));
  	}
  
  	for (i = 0; i < areq->tsgls; i++)
  		put_page(sg_page(sg + i));
  
  	sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
  	sock_kfree_s(sk, req, reqlen);
  	__sock_put(sk);
  	iocb->ki_complete(iocb, err, err);
  }
  
  static int aead_recvmsg_async(struct socket *sock, struct msghdr *msg,
  			      int flags)
  {
  	struct sock *sk = sock->sk;
  	struct alg_sock *ask = alg_sk(sk);
  	struct aead_ctx *ctx = ask->private;
  	struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
  	struct aead_async_req *areq;
  	struct aead_request *req = NULL;
  	struct aead_sg_list *sgl = &ctx->tsgl;
  	struct aead_async_rsgl *last_rsgl = NULL, *rsgl;
  	unsigned int as = crypto_aead_authsize(tfm);
  	unsigned int i, reqlen = GET_REQ_SIZE(tfm);
  	int err = -ENOMEM;
  	unsigned long used;
  	size_t outlen;
  	size_t usedpages = 0;
  
  	lock_sock(sk);
  	if (ctx->more) {
  		err = aead_wait_for_data(sk, flags);
  		if (err)
  			goto unlock;
  	}
  
  	used = ctx->used;
  	outlen = used;
  
  	if (!aead_sufficient_data(ctx))
  		goto unlock;
  
  	req = sock_kmalloc(sk, reqlen, GFP_KERNEL);
  	if (unlikely(!req))
  		goto unlock;
  
  	areq = GET_ASYM_REQ(req, tfm);
  	memset(&areq->first_rsgl, '\0', sizeof(areq->first_rsgl));
  	INIT_LIST_HEAD(&areq->list);
  	areq->iocb = msg->msg_iocb;
  	memcpy(areq->iv, ctx->iv, crypto_aead_ivsize(tfm));
  	aead_request_set_tfm(req, tfm);
  	aead_request_set_ad(req, ctx->aead_assoclen);
  	aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
  				  aead_async_cb, sk);
  	used -= ctx->aead_assoclen + (ctx->enc ? as : 0);
  
  	/* take over all tx sgls from ctx */
  	areq->tsgl = sock_kmalloc(sk, sizeof(*areq->tsgl) * sgl->cur,
  				  GFP_KERNEL);
  	if (unlikely(!areq->tsgl))
  		goto free;
  
  	sg_init_table(areq->tsgl, sgl->cur);
  	for (i = 0; i < sgl->cur; i++)
  		sg_set_page(&areq->tsgl[i], sg_page(&sgl->sg[i]),
  			    sgl->sg[i].length, sgl->sg[i].offset);
  
  	areq->tsgls = sgl->cur;
  
  	/* create rx sgls */
  	while (iov_iter_count(&msg->msg_iter)) {
  		size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
  				      (outlen - usedpages));
  
  		if (list_empty(&areq->list)) {
  			rsgl = &areq->first_rsgl;
  
  		} else {
  			rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
  			if (unlikely(!rsgl)) {
  				err = -ENOMEM;
  				goto free;
  			}
  		}
  		rsgl->sgl.npages = 0;
  		list_add_tail(&rsgl->list, &areq->list);
  
  		/* make one iovec available as scatterlist */
  		err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
  		if (err < 0)
  			goto free;
  
  		usedpages += err;
  
  		/* chain the new scatterlist with previous one */
  		if (last_rsgl)
  			af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
  
  		last_rsgl = rsgl;
  
  		/* we do not need more iovecs as we have sufficient memory */
  		if (outlen <= usedpages)
  			break;
  
  		iov_iter_advance(&msg->msg_iter, err);
  	}
  	err = -EINVAL;
  	/* ensure output buffer is sufficiently large */
  	if (usedpages < outlen)
  		goto free;
  
  	aead_request_set_crypt(req, areq->tsgl, areq->first_rsgl.sgl.sg, used,
  			       areq->iv);
  	err = ctx->enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req);
  	if (err) {
  		if (err == -EINPROGRESS) {
  			sock_hold(sk);
  			err = -EIOCBQUEUED;
  			aead_reset_ctx(ctx);
  			goto unlock;
  		} else if (err == -EBADMSG) {
  			aead_put_sgl(sk);
  		}
  		goto free;
  	}
  	aead_put_sgl(sk);
  
  free:
  	list_for_each_entry(rsgl, &areq->list, list) {
  		af_alg_free_sg(&rsgl->sgl);
  		if (rsgl != &areq->first_rsgl)
  			sock_kfree_s(sk, rsgl, sizeof(*rsgl));
  	}
  	if (areq->tsgl)
  		sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
  	if (req)
  		sock_kfree_s(sk, req, reqlen);
  unlock:
  	aead_wmem_wakeup(sk);
  	release_sock(sk);
  	return err ? err : outlen;
  }
  
  static int aead_recvmsg_sync(struct socket *sock, struct msghdr *msg, int flags)

  {
  	struct sock *sk = sock->sk;
  	struct alg_sock *ask = alg_sk(sk);
  	struct aead_ctx *ctx = ask->private;

  	unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
  	struct aead_sg_list *sgl = &ctx->tsgl;

  	struct aead_async_rsgl *last_rsgl = NULL;
  	struct aead_async_rsgl *rsgl, *tmp;

  	int err = -EINVAL;
  	unsigned long used = 0;
  	size_t outlen = 0;
  	size_t usedpages = 0;

  
  	lock_sock(sk);
  
  	/*
  	 * AEAD memory structure: For encryption, the tag is appended to the
  	 * ciphertext which implies that the memory allocated for the ciphertext
  	 * must be increased by the tag length. For decryption, the tag
  	 * is expected to be concatenated to the ciphertext. The plaintext
  	 * therefore has a memory size of the ciphertext minus the tag length.
  	 *
  	 * The memory structure for cipher operation has the following
  	 * structure:
  	 *	AEAD encryption input:  assoc data || plaintext
  	 *	AEAD encryption output: cipherntext || auth tag
  	 *	AEAD decryption input:  assoc data || ciphertext || auth tag
  	 *	AEAD decryption output: plaintext
  	 */
  
  	if (ctx->more) {
  		err = aead_wait_for_data(sk, flags);
  		if (err)
  			goto unlock;
  	}
  
  	used = ctx->used;
  
  	/*
  	 * Make sure sufficient data is present -- note, the same check is
  	 * is also present in sendmsg/sendpage. The checks in sendpage/sendmsg
  	 * shall provide an information to the data sender that something is
  	 * wrong, but they are irrelevant to maintain the kernel integrity.
  	 * We need this check here too in case user space decides to not honor
  	 * the error message in sendmsg/sendpage and still call recvmsg. This
  	 * check here protects the kernel integrity.
  	 */
  	if (!aead_sufficient_data(ctx))
  		goto unlock;

  	outlen = used;

  	/*
  	 * The cipher operation input data is reduced by the associated data
  	 * length as this data is processed separately later on.
  	 */

  	used -= ctx->aead_assoclen + (ctx->enc ? as : 0);

  
  	/* convert iovecs of output buffers into scatterlists */
  	while (iov_iter_count(&msg->msg_iter)) {
  		size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
  				      (outlen - usedpages));

  		if (list_empty(&ctx->list)) {
  			rsgl = &ctx->first_rsgl;
  		} else {
  			rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
  			if (unlikely(!rsgl)) {
  				err = -ENOMEM;
  				goto unlock;
  			}
  		}
  		rsgl->sgl.npages = 0;
  		list_add_tail(&rsgl->list, &ctx->list);

  		/* make one iovec available as scatterlist */

  		err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);

  		if (err < 0)
  			goto unlock;
  		usedpages += err;

  		/* chain the new scatterlist with previous one */

  		if (last_rsgl)
  			af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
  
  		last_rsgl = rsgl;

  		/* we do not need more iovecs as we have sufficient memory */
  		if (outlen <= usedpages)
  			break;
  		iov_iter_advance(&msg->msg_iter, err);

  	}
  
  	err = -EINVAL;
  	/* ensure output buffer is sufficiently large */
  	if (usedpages < outlen)
  		goto unlock;

  	sg_mark_end(sgl->sg + sgl->cur - 1);

  	aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx->first_rsgl.sgl.sg,

  			       used, ctx->iv);
  	aead_request_set_ad(&ctx->aead_req, ctx->aead_assoclen);

  
  	err = af_alg_wait_for_completion(ctx->enc ?
  					 crypto_aead_encrypt(&ctx->aead_req) :
  					 crypto_aead_decrypt(&ctx->aead_req),
  					 &ctx->completion);
  
  	if (err) {
  		/* EBADMSG implies a valid cipher operation took place */
  		if (err == -EBADMSG)
  			aead_put_sgl(sk);

  		goto unlock;
  	}
  
  	aead_put_sgl(sk);

  	err = 0;
  
  unlock:

  	list_for_each_entry_safe(rsgl, tmp, &ctx->list, list) {
  		af_alg_free_sg(&rsgl->sgl);
  		if (rsgl != &ctx->first_rsgl)
  			sock_kfree_s(sk, rsgl, sizeof(*rsgl));
  		list_del(&rsgl->list);
  	}
  	INIT_LIST_HEAD(&ctx->list);

  	aead_wmem_wakeup(sk);
  	release_sock(sk);
  
  	return err ? err : outlen;
  }

  static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
  			int flags)
  {
  	return (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) ?
  		aead_recvmsg_async(sock, msg, flags) :
  		aead_recvmsg_sync(sock, msg, flags);
  }

  static unsigned int aead_poll(struct file *file, struct socket *sock,
  			      poll_table *wait)
  {
  	struct sock *sk = sock->sk;
  	struct alg_sock *ask = alg_sk(sk);
  	struct aead_ctx *ctx = ask->private;
  	unsigned int mask;
  
  	sock_poll_wait(file, sk_sleep(sk), wait);
  	mask = 0;
  
  	if (!ctx->more)
  		mask |= POLLIN | POLLRDNORM;
  
  	if (aead_writable(sk))
  		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
  
  	return mask;
  }
  
  static struct proto_ops algif_aead_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,
  	.accept		=	sock_no_accept,
  	.setsockopt	=	sock_no_setsockopt,
  
  	.release	=	af_alg_release,
  	.sendmsg	=	aead_sendmsg,
  	.sendpage	=	aead_sendpage,
  	.recvmsg	=	aead_recvmsg,
  	.poll		=	aead_poll,
  };
  
  static void *aead_bind(const char *name, u32 type, u32 mask)
  {

  	return crypto_alloc_aead(name, type, mask);

  }
  
  static void aead_release(void *private)
  {
  	crypto_free_aead(private);
  }
  
  static int aead_setauthsize(void *private, unsigned int authsize)
  {
  	return crypto_aead_setauthsize(private, authsize);
  }
  
  static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
  {
  	return crypto_aead_setkey(private, key, keylen);
  }
  
  static void aead_sock_destruct(struct sock *sk)
  {
  	struct alg_sock *ask = alg_sk(sk);
  	struct aead_ctx *ctx = ask->private;
  	unsigned int ivlen = crypto_aead_ivsize(
  				crypto_aead_reqtfm(&ctx->aead_req));

  	WARN_ON(atomic_read(&sk->sk_refcnt) != 0);

  	aead_put_sgl(sk);
  	sock_kzfree_s(sk, ctx->iv, ivlen);
  	sock_kfree_s(sk, ctx, ctx->len);
  	af_alg_release_parent(sk);
  }
  
  static int aead_accept_parent(void *private, struct sock *sk)
  {
  	struct aead_ctx *ctx;
  	struct alg_sock *ask = alg_sk(sk);
  	unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(private);
  	unsigned int ivlen = crypto_aead_ivsize(private);
  
  	ctx = sock_kmalloc(sk, len, GFP_KERNEL);
  	if (!ctx)
  		return -ENOMEM;
  	memset(ctx, 0, len);
  
  	ctx->iv = sock_kmalloc(sk, ivlen, GFP_KERNEL);
  	if (!ctx->iv) {
  		sock_kfree_s(sk, ctx, len);
  		return -ENOMEM;
  	}
  	memset(ctx->iv, 0, ivlen);
  
  	ctx->len = len;
  	ctx->used = 0;
  	ctx->more = 0;
  	ctx->merge = 0;
  	ctx->enc = 0;
  	ctx->tsgl.cur = 0;
  	ctx->aead_assoclen = 0;
  	af_alg_init_completion(&ctx->completion);
  	sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);

  	INIT_LIST_HEAD(&ctx->list);

  
  	ask->private = ctx;
  
  	aead_request_set_tfm(&ctx->aead_req, private);
  	aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
  				  af_alg_complete, &ctx->completion);
  
  	sk->sk_destruct = aead_sock_destruct;
  
  	return 0;
  }
  
  static const struct af_alg_type algif_type_aead = {
  	.bind		=	aead_bind,
  	.release	=	aead_release,
  	.setkey		=	aead_setkey,
  	.setauthsize	=	aead_setauthsize,
  	.accept		=	aead_accept_parent,
  	.ops		=	&algif_aead_ops,
  	.name		=	"aead",
  	.owner		=	THIS_MODULE
  };
  
  static int __init algif_aead_init(void)
  {
  	return af_alg_register_type(&algif_type_aead);
  }
  
  static void __exit algif_aead_exit(void)
  {
  	int err = af_alg_unregister_type(&algif_type_aead);
  	BUG_ON(err);
  }
  
  module_init(algif_aead_init);
  module_exit(algif_aead_exit);
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
  MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");