1 files changed, 854 insertions, 0 deletions

diff --git a/kernel/crypto/algif_skcipher.c b/kernel/crypto/algif_skcipher.c
new file mode 100644
index 000000000..945075292
--- /dev/null
+++ b/kernel/crypto/algif_skcipher.c
@@ -0,0 +1,854 @@
+/*
+ * algif_skcipher: User-space interface for skcipher algorithms
+ *
+ * This file provides the user-space API for symmetric key ciphers.
+ *
+ * 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/scatterwalk.h>
+#include <crypto/skcipher.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 skcipher_sg_list {
+	struct list_head list;
+
+	int cur;
+
+	struct scatterlist sg[0];
+};
+
+struct skcipher_ctx {
+	struct list_head tsgl;
+	struct af_alg_sgl rsgl;
+
+	void *iv;
+
+	struct af_alg_completion completion;
+
+	atomic_t inflight;
+	unsigned used;
+
+	unsigned int len;
+	bool more;
+	bool merge;
+	bool enc;
+
+	struct ablkcipher_request req;
+};
+
+struct skcipher_async_rsgl {
+	struct af_alg_sgl sgl;
+	struct list_head list;
+};
+
+struct skcipher_async_req {
+	struct kiocb *iocb;
+	struct skcipher_async_rsgl first_sgl;
+	struct list_head list;
+	struct scatterlist *tsg;
+	char iv[];
+};
+
+#define GET_SREQ(areq, ctx) (struct skcipher_async_req *)((char *)areq + \
+	crypto_ablkcipher_reqsize(crypto_ablkcipher_reqtfm(&ctx->req)))
+
+#define GET_REQ_SIZE(ctx) \
+	crypto_ablkcipher_reqsize(crypto_ablkcipher_reqtfm(&ctx->req))
+
+#define GET_IV_SIZE(ctx) \
+	crypto_ablkcipher_ivsize(crypto_ablkcipher_reqtfm(&ctx->req))
+
+#define MAX_SGL_ENTS ((4096 - sizeof(struct skcipher_sg_list)) / \
+		      sizeof(struct scatterlist) - 1)
+
+static void skcipher_free_async_sgls(struct skcipher_async_req *sreq)
+{
+	struct skcipher_async_rsgl *rsgl, *tmp;
+	struct scatterlist *sgl;
+	struct scatterlist *sg;
+	int i, n;
+
+	list_for_each_entry_safe(rsgl, tmp, &sreq->list, list) {
+		af_alg_free_sg(&rsgl->sgl);
+		if (rsgl != &sreq->first_sgl)
+			kfree(rsgl);
+	}
+	sgl = sreq->tsg;
+	n = sg_nents(sgl);
+	for_each_sg(sgl, sg, n, i)
+		put_page(sg_page(sg));
+
+	kfree(sreq->tsg);
+}
+
+static void skcipher_async_cb(struct crypto_async_request *req, int err)
+{
+	struct sock *sk = req->data;
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	struct skcipher_async_req *sreq = GET_SREQ(req, ctx);
+	struct kiocb *iocb = sreq->iocb;
+
+	atomic_dec(&ctx->inflight);
+	skcipher_free_async_sgls(sreq);
+	kfree(req);
+	iocb->ki_complete(iocb, err, err);
+}
+
+static inline int skcipher_sndbuf(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+
+	return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
+			  ctx->used, 0);
+}
+
+static inline bool skcipher_writable(struct sock *sk)
+{
+	return PAGE_SIZE <= skcipher_sndbuf(sk);
+}
+
+static int skcipher_alloc_sgl(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	struct skcipher_sg_list *sgl;
+	struct scatterlist *sg = NULL;
+
+	sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
+	if (!list_empty(&ctx->tsgl))
+		sg = sgl->sg;
+
+	if (!sg || sgl->cur >= MAX_SGL_ENTS) {
+		sgl = sock_kmalloc(sk, sizeof(*sgl) +
+				       sizeof(sgl->sg[0]) * (MAX_SGL_ENTS + 1),
+				   GFP_KERNEL);
+		if (!sgl)
+			return -ENOMEM;
+
+		sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
+		sgl->cur = 0;
+
+		if (sg)
+			scatterwalk_sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
+
+		list_add_tail(&sgl->list, &ctx->tsgl);
+	}
+
+	return 0;
+}
+
+static void skcipher_pull_sgl(struct sock *sk, int used, int put)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	struct skcipher_sg_list *sgl;
+	struct scatterlist *sg;
+	int i;
+
+	while (!list_empty(&ctx->tsgl)) {
+		sgl = list_first_entry(&ctx->tsgl, struct skcipher_sg_list,
+				       list);
+		sg = sgl->sg;
+
+		for (i = 0; i < sgl->cur; i++) {
+			int plen = min_t(int, used, sg[i].length);
+
+			if (!sg_page(sg + i))
+				continue;
+
+			sg[i].length -= plen;
+			sg[i].offset += plen;
+
+			used -= plen;
+			ctx->used -= plen;
+
+			if (sg[i].length)
+				return;
+			if (put)
+				put_page(sg_page(sg + i));
+			sg_assign_page(sg + i, NULL);
+		}
+
+		list_del(&sgl->list);
+		sock_kfree_s(sk, sgl,
+			     sizeof(*sgl) + sizeof(sgl->sg[0]) *
+					    (MAX_SGL_ENTS + 1));
+	}
+
+	if (!ctx->used)
+		ctx->merge = 0;
+}
+
+static void skcipher_free_sgl(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+
+	skcipher_pull_sgl(sk, ctx->used, 1);
+}
+
+static int skcipher_wait_for_wmem(struct sock *sk, unsigned flags)
+{
+	long timeout;
+	DEFINE_WAIT(wait);
+	int err = -ERESTARTSYS;
+
+	if (flags & MSG_DONTWAIT)
+		return -EAGAIN;
+
+	set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+
+	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, skcipher_writable(sk))) {
+			err = 0;
+			break;
+		}
+	}
+	finish_wait(sk_sleep(sk), &wait);
+
+	return err;
+}
+
+static void skcipher_wmem_wakeup(struct sock *sk)
+{
+	struct socket_wq *wq;
+
+	if (!skcipher_writable(sk))
+		return;
+
+	rcu_read_lock();
+	wq = rcu_dereference(sk->sk_wq);
+	if (wq_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 skcipher_wait_for_data(struct sock *sk, unsigned flags)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	long timeout;
+	DEFINE_WAIT(wait);
+	int err = -ERESTARTSYS;
+
+	if (flags & MSG_DONTWAIT) {
+		return -EAGAIN;
+	}
+
+	set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+
+	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->used)) {
+			err = 0;
+			break;
+		}
+	}
+	finish_wait(sk_sleep(sk), &wait);
+
+	clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+
+	return err;
+}
+
+static void skcipher_data_wakeup(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	struct socket_wq *wq;
+
+	if (!ctx->used)
+		return;
+
+	rcu_read_lock();
+	wq = rcu_dereference(sk->sk_wq);
+	if (wq_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 skcipher_sendmsg(struct socket *sock, struct msghdr *msg,
+			    size_t size)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
+	unsigned ivsize = crypto_ablkcipher_ivsize(tfm);
+	struct skcipher_sg_list *sgl;
+	struct af_alg_control con = {};
+	long copied = 0;
+	bool enc = 0;
+	bool init = 0;
+	int err;
+	int i;
+
+	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;
+	}
+
+	err = -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);
+	}
+
+	while (size) {
+		struct scatterlist *sg;
+		unsigned long len = size;
+		int plen;
+
+		if (ctx->merge) {
+			sgl = list_entry(ctx->tsgl.prev,
+					 struct skcipher_sg_list, list);
+			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 (!skcipher_writable(sk)) {
+			err = skcipher_wait_for_wmem(sk, msg->msg_flags);
+			if (err)
+				goto unlock;
+		}
+
+		len = min_t(unsigned long, len, skcipher_sndbuf(sk));
+
+		err = skcipher_alloc_sgl(sk);
+		if (err)
+			goto unlock;
+
+		sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
+		sg = sgl->sg;
+		sg_unmark_end(sg + sgl->cur);
+		do {
+			i = sgl->cur;
+			plen = min_t(int, len, PAGE_SIZE);
+
+			sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
+			err = -ENOMEM;
+			if (!sg_page(sg + i))
+				goto unlock;
+
+			err = memcpy_from_msg(page_address(sg_page(sg + i)),
+					      msg, plen);
+			if (err) {
+				__free_page(sg_page(sg + i));
+				sg_assign_page(sg + i, NULL);
+				goto unlock;
+			}
+
+			sg[i].length = plen;
+			len -= plen;
+			ctx->used += plen;
+			copied += plen;
+			size -= plen;
+			sgl->cur++;
+		} while (len && sgl->cur < MAX_SGL_ENTS);
+
+		if (!size)
+			sg_mark_end(sg + sgl->cur - 1);
+
+		ctx->merge = plen & (PAGE_SIZE - 1);
+	}
+
+	err = 0;
+
+	ctx->more = msg->msg_flags & MSG_MORE;
+
+unlock:
+	skcipher_data_wakeup(sk);
+	release_sock(sk);
+
+	return copied ?: err;
+}
+
+static ssize_t skcipher_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 skcipher_ctx *ctx = ask->private;
+	struct skcipher_sg_list *sgl;
+	int err = -EINVAL;
+
+	if (flags & MSG_SENDPAGE_NOTLAST)
+		flags |= MSG_MORE;
+
+	lock_sock(sk);
+	if (!ctx->more && ctx->used)
+		goto unlock;
+
+	if (!size)
+		goto done;
+
+	if (!skcipher_writable(sk)) {
+		err = skcipher_wait_for_wmem(sk, flags);
+		if (err)
+			goto unlock;
+	}
+
+	err = skcipher_alloc_sgl(sk);
+	if (err)
+		goto unlock;
+
+	ctx->merge = 0;
+	sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
+
+	if (sgl->cur)
+		sg_unmark_end(sgl->sg + sgl->cur - 1);
+
+	sg_mark_end(sgl->sg + sgl->cur);
+	get_page(page);
+	sg_set_page(sgl->sg + sgl->cur, page, size, offset);
+	sgl->cur++;
+	ctx->used += size;
+
+done:
+	ctx->more = flags & MSG_MORE;
+
+unlock:
+	skcipher_data_wakeup(sk);
+	release_sock(sk);
+
+	return err ?: size;
+}
+
+static int skcipher_all_sg_nents(struct skcipher_ctx *ctx)
+{
+	struct skcipher_sg_list *sgl;
+	struct scatterlist *sg;
+	int nents = 0;
+
+	list_for_each_entry(sgl, &ctx->tsgl, list) {
+		sg = sgl->sg;
+
+		while (!sg->length)
+			sg++;
+
+		nents += sg_nents(sg);
+	}
+	return nents;
+}
+
+static int skcipher_recvmsg_async(struct socket *sock, struct msghdr *msg,
+				  int flags)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	struct skcipher_sg_list *sgl;
+	struct scatterlist *sg;
+	struct skcipher_async_req *sreq;
+	struct ablkcipher_request *req;
+	struct skcipher_async_rsgl *last_rsgl = NULL;
+	unsigned int txbufs = 0, len = 0, tx_nents = skcipher_all_sg_nents(ctx);
+	unsigned int reqlen = sizeof(struct skcipher_async_req) +
+				GET_REQ_SIZE(ctx) + GET_IV_SIZE(ctx);
+	int err = -ENOMEM;
+	bool mark = false;
+
+	lock_sock(sk);
+	req = kmalloc(reqlen, GFP_KERNEL);
+	if (unlikely(!req))
+		goto unlock;
+
+	sreq = GET_SREQ(req, ctx);
+	sreq->iocb = msg->msg_iocb;
+	memset(&sreq->first_sgl, '\0', sizeof(struct skcipher_async_rsgl));
+	INIT_LIST_HEAD(&sreq->list);
+	sreq->tsg = kcalloc(tx_nents, sizeof(*sg), GFP_KERNEL);
+	if (unlikely(!sreq->tsg)) {
+		kfree(req);
+		goto unlock;
+	}
+	sg_init_table(sreq->tsg, tx_nents);
+	memcpy(sreq->iv, ctx->iv, GET_IV_SIZE(ctx));
+	ablkcipher_request_set_tfm(req, crypto_ablkcipher_reqtfm(&ctx->req));
+	ablkcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+					skcipher_async_cb, sk);
+
+	while (iov_iter_count(&msg->msg_iter)) {
+		struct skcipher_async_rsgl *rsgl;
+		int used;
+
+		if (!ctx->used) {
+			err = skcipher_wait_for_data(sk, flags);
+			if (err)
+				goto free;
+		}
+		sgl = list_first_entry(&ctx->tsgl,
+				       struct skcipher_sg_list, list);
+		sg = sgl->sg;
+
+		while (!sg->length)
+			sg++;
+
+		used = min_t(unsigned long, ctx->used,
+			     iov_iter_count(&msg->msg_iter));
+		used = min_t(unsigned long, used, sg->length);
+
+		if (txbufs == tx_nents) {
+			struct scatterlist *tmp;
+			int x;
+			/* Ran out of tx slots in async request
+			 * need to expand */
+			tmp = kcalloc(tx_nents * 2, sizeof(*tmp),
+				      GFP_KERNEL);
+			if (!tmp)
+				goto free;
+
+			sg_init_table(tmp, tx_nents * 2);
+			for (x = 0; x < tx_nents; x++)
+				sg_set_page(&tmp[x], sg_page(&sreq->tsg[x]),
+					    sreq->tsg[x].length,
+					    sreq->tsg[x].offset);
+			kfree(sreq->tsg);
+			sreq->tsg = tmp;
+			tx_nents *= 2;
+			mark = true;
+		}
+		/* Need to take over the tx sgl from ctx
+		 * to the asynch req - these sgls will be freed later */
+		sg_set_page(sreq->tsg + txbufs++, sg_page(sg), sg->length,
+			    sg->offset);
+
+		if (list_empty(&sreq->list)) {
+			rsgl = &sreq->first_sgl;
+			list_add_tail(&rsgl->list, &sreq->list);
+		} else {
+			rsgl = kmalloc(sizeof(*rsgl), GFP_KERNEL);
+			if (!rsgl) {
+				err = -ENOMEM;
+				goto free;
+			}
+			list_add_tail(&rsgl->list, &sreq->list);
+		}
+
+		used = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, used);
+		err = used;
+		if (used < 0)
+			goto free;
+		if (last_rsgl)
+			af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
+
+		last_rsgl = rsgl;
+		len += used;
+		skcipher_pull_sgl(sk, used, 0);
+		iov_iter_advance(&msg->msg_iter, used);
+	}
+
+	if (mark)
+		sg_mark_end(sreq->tsg + txbufs - 1);
+
+	ablkcipher_request_set_crypt(req, sreq->tsg, sreq->first_sgl.sgl.sg,
+				     len, sreq->iv);
+	err = ctx->enc ? crypto_ablkcipher_encrypt(req) :
+			 crypto_ablkcipher_decrypt(req);
+	if (err == -EINPROGRESS) {
+		atomic_inc(&ctx->inflight);
+		err = -EIOCBQUEUED;
+		goto unlock;
+	}
+free:
+	skcipher_free_async_sgls(sreq);
+	kfree(req);
+unlock:
+	skcipher_wmem_wakeup(sk);
+	release_sock(sk);
+	return err;
+}
+
+static int skcipher_recvmsg_sync(struct socket *sock, struct msghdr *msg,
+				 int flags)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	unsigned bs = crypto_ablkcipher_blocksize(crypto_ablkcipher_reqtfm(
+		&ctx->req));
+	struct skcipher_sg_list *sgl;
+	struct scatterlist *sg;
+	int err = -EAGAIN;
+	int used;
+	long copied = 0;
+
+	lock_sock(sk);
+	while (msg_data_left(msg)) {
+		sgl = list_first_entry(&ctx->tsgl,
+				       struct skcipher_sg_list, list);
+		sg = sgl->sg;
+
+		while (!sg->length)
+			sg++;
+
+		if (!ctx->used) {
+			err = skcipher_wait_for_data(sk, flags);
+			if (err)
+				goto unlock;
+		}
+
+		used = min_t(unsigned long, ctx->used, msg_data_left(msg));
+
+		used = af_alg_make_sg(&ctx->rsgl, &msg->msg_iter, used);
+		err = used;
+		if (err < 0)
+			goto unlock;
+
+		if (ctx->more || used < ctx->used)
+			used -= used % bs;
+
+		err = -EINVAL;
+		if (!used)
+			goto free;
+
+		ablkcipher_request_set_crypt(&ctx->req, sg,
+					     ctx->rsgl.sg, used,
+					     ctx->iv);
+
+		err = af_alg_wait_for_completion(
+				ctx->enc ?
+					crypto_ablkcipher_encrypt(&ctx->req) :
+					crypto_ablkcipher_decrypt(&ctx->req),
+				&ctx->completion);
+
+free:
+		af_alg_free_sg(&ctx->rsgl);
+
+		if (err)
+			goto unlock;
+
+		copied += used;
+		skcipher_pull_sgl(sk, used, 1);
+		iov_iter_advance(&msg->msg_iter, used);
+	}
+
+	err = 0;
+
+unlock:
+	skcipher_wmem_wakeup(sk);
+	release_sock(sk);
+
+	return copied ?: err;
+}
+
+static int skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
+			    size_t ignored, int flags)
+{
+	return (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) ?
+		skcipher_recvmsg_async(sock, msg, flags) :
+		skcipher_recvmsg_sync(sock, msg, flags);
+}
+
+static unsigned int skcipher_poll(struct file *file, struct socket *sock,
+				  poll_table *wait)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	unsigned int mask;
+
+	sock_poll_wait(file, sk_sleep(sk), wait);
+	mask = 0;
+
+	if (ctx->used)
+		mask |= POLLIN | POLLRDNORM;
+
+	if (skcipher_writable(sk))
+		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
+
+	return mask;
+}
+
+static struct proto_ops algif_skcipher_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	=	skcipher_sendmsg,
+	.sendpage	=	skcipher_sendpage,
+	.recvmsg	=	skcipher_recvmsg,
+	.poll		=	skcipher_poll,
+};
+
+static void *skcipher_bind(const char *name, u32 type, u32 mask)
+{
+	return crypto_alloc_ablkcipher(name, type, mask);
+}
+
+static void skcipher_release(void *private)
+{
+	crypto_free_ablkcipher(private);
+}
+
+static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
+{
+	return crypto_ablkcipher_setkey(private, key, keylen);
+}
+
+static void skcipher_wait(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	int ctr = 0;
+
+	while (atomic_read(&ctx->inflight) && ctr++ < 100)
+		msleep(100);
+}
+
+static void skcipher_sock_destruct(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct skcipher_ctx *ctx = ask->private;
+	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
+
+	if (atomic_read(&ctx->inflight))
+		skcipher_wait(sk);
+
+	skcipher_free_sgl(sk);
+	sock_kzfree_s(sk, ctx->iv, crypto_ablkcipher_ivsize(tfm));
+	sock_kfree_s(sk, ctx, ctx->len);
+	af_alg_release_parent(sk);
+}
+
+static int skcipher_accept_parent(void *private, struct sock *sk)
+{
+	struct skcipher_ctx *ctx;
+	struct alg_sock *ask = alg_sk(sk);
+	unsigned int len = sizeof(*ctx) + crypto_ablkcipher_reqsize(private);
+
+	ctx = sock_kmalloc(sk, len, GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->iv = sock_kmalloc(sk, crypto_ablkcipher_ivsize(private),
+			       GFP_KERNEL);
+	if (!ctx->iv) {
+		sock_kfree_s(sk, ctx, len);
+		return -ENOMEM;
+	}
+
+	memset(ctx->iv, 0, crypto_ablkcipher_ivsize(private));
+
+	INIT_LIST_HEAD(&ctx->tsgl);
+	ctx->len = len;
+	ctx->used = 0;
+	ctx->more = 0;
+	ctx->merge = 0;
+	ctx->enc = 0;
+	atomic_set(&ctx->inflight, 0);
+	af_alg_init_completion(&ctx->completion);
+
+	ask->private = ctx;
+
+	ablkcipher_request_set_tfm(&ctx->req, private);
+	ablkcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+					af_alg_complete, &ctx->completion);
+
+	sk->sk_destruct = skcipher_sock_destruct;
+
+	return 0;
+}
+
+static const struct af_alg_type algif_type_skcipher = {
+	.bind		=	skcipher_bind,
+	.release	=	skcipher_release,
+	.setkey		=	skcipher_setkey,
+	.accept		=	skcipher_accept_parent,
+	.ops		=	&algif_skcipher_ops,
+	.name		=	"skcipher",
+	.owner		=	THIS_MODULE
+};
+
+static int __init algif_skcipher_init(void)
+{
+	return af_alg_register_type(&algif_type_skcipher);
+}
+
+static void __exit algif_skcipher_exit(void)
+{
+	int err = af_alg_unregister_type(&algif_type_skcipher);
+	BUG_ON(err);
+}
+
+module_init(algif_skcipher_init);
+module_exit(algif_skcipher_exit);
+MODULE_LICENSE("GPL");