tls: kernel TLS support

Software implementation of transport layer security, implemented using ULP
infrastructure.  tcp proto_ops are replaced with tls equivalents of sendmsg and
sendpage.

Only symmetric crypto is done in the kernel, keys are passed by setsockopt
after the handshake is complete.  All control messages are supported via CMSG
data - the actual symmetric encryption is the same, just the message type needs
to be passed separately.

For user API, please see Documentation patch.

Pieces that can be shared between hw and sw implementation
are in tls_main.c

Signed-off-by: Boris Pismenny <borisp@mellanox.com>
Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: Aviad Yehezkel <aviadye@mellanox.com>
Signed-off-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 772 insertions, 0 deletions

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
new file mode 100644
index 000000000000..fa596fa71ba7
--- /dev/null
+++ b/net/tls/tls_sw.c
@@ -0,0 +1,772 @@
+/*
+ * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. All rights reserved.
+ * Copyright (c) 2016-2017, Lance Chao <lancerchao@fb.com>. All rights reserved.
+ * Copyright (c) 2016, Fridolin Pokorny <fridolin.pokorny@gmail.com>. All rights reserved.
+ * Copyright (c) 2016, Nikos Mavrogiannopoulos <nmav@gnutls.org>. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <crypto/aead.h>
+
+#include <net/tls.h>
+
+static inline void tls_make_aad(int recv,
+				char *buf,
+				size_t size,
+				char *record_sequence,
+				int record_sequence_size,
+				unsigned char record_type)
+{
+	memcpy(buf, record_sequence, record_sequence_size);
+
+	buf[8] = record_type;
+	buf[9] = TLS_1_2_VERSION_MAJOR;
+	buf[10] = TLS_1_2_VERSION_MINOR;
+	buf[11] = size >> 8;
+	buf[12] = size & 0xFF;
+}
+
+static void trim_sg(struct sock *sk, struct scatterlist *sg,
+		    int *sg_num_elem, unsigned int *sg_size, int target_size)
+{
+	int i = *sg_num_elem - 1;
+	int trim = *sg_size - target_size;
+
+	if (trim <= 0) {
+		WARN_ON(trim < 0);
+		return;
+	}
+
+	*sg_size = target_size;
+	while (trim >= sg[i].length) {
+		trim -= sg[i].length;
+		sk_mem_uncharge(sk, sg[i].length);
+		put_page(sg_page(&sg[i]));
+		i--;
+
+		if (i < 0)
+			goto out;
+	}
+
+	sg[i].length -= trim;
+	sk_mem_uncharge(sk, trim);
+
+out:
+	*sg_num_elem = i + 1;
+}
+
+static void trim_both_sgl(struct sock *sk, int target_size)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
+
+	trim_sg(sk, ctx->sg_plaintext_data,
+		&ctx->sg_plaintext_num_elem,
+		&ctx->sg_plaintext_size,
+		target_size);
+
+	if (target_size > 0)
+		target_size += tls_ctx->overhead_size;
+
+	trim_sg(sk, ctx->sg_encrypted_data,
+		&ctx->sg_encrypted_num_elem,
+		&ctx->sg_encrypted_size,
+		target_size);
+}
+
+static int alloc_sg(struct sock *sk, int len, struct scatterlist *sg,
+		    int *sg_num_elem, unsigned int *sg_size,
+		    int first_coalesce)
+{
+	struct page_frag *pfrag;
+	unsigned int size = *sg_size;
+	int num_elem = *sg_num_elem, use = 0, rc = 0;
+	struct scatterlist *sge;
+	unsigned int orig_offset;
+
+	len -= size;
+	pfrag = sk_page_frag(sk);
+
+	while (len > 0) {
+		if (!sk_page_frag_refill(sk, pfrag)) {
+			rc = -ENOMEM;
+			goto out;
+		}
+
+		use = min_t(int, len, pfrag->size - pfrag->offset);
+
+		if (!sk_wmem_schedule(sk, use)) {
+			rc = -ENOMEM;
+			goto out;
+		}
+
+		sk_mem_charge(sk, use);
+		size += use;
+		orig_offset = pfrag->offset;
+		pfrag->offset += use;
+
+		sge = sg + num_elem - 1;
+		if (num_elem > first_coalesce && sg_page(sg) == pfrag->page &&
+		    sg->offset + sg->length == orig_offset) {
+			sg->length += use;
+		} else {
+			sge++;
+			sg_unmark_end(sge);
+			sg_set_page(sge, pfrag->page, use, orig_offset);
+			get_page(pfrag->page);
+			++num_elem;
+			if (num_elem == MAX_SKB_FRAGS) {
+				rc = -ENOSPC;
+				break;
+			}
+		}
+
+		len -= use;
+	}
+	goto out;
+
+out:
+	*sg_size = size;
+	*sg_num_elem = num_elem;
+	return rc;
+}
+
+static int alloc_encrypted_sg(struct sock *sk, int len)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
+	int rc = 0;
+
+	rc = alloc_sg(sk, len, ctx->sg_encrypted_data,
+		      &ctx->sg_encrypted_num_elem, &ctx->sg_encrypted_size, 0);
+
+	return rc;
+}
+
+static int alloc_plaintext_sg(struct sock *sk, int len)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
+	int rc = 0;
+
+	rc = alloc_sg(sk, len, ctx->sg_plaintext_data,
+		      &ctx->sg_plaintext_num_elem, &ctx->sg_plaintext_size,
+		      tls_ctx->pending_open_record_frags);
+
+	return rc;
+}
+
+static void free_sg(struct sock *sk, struct scatterlist *sg,
+		    int *sg_num_elem, unsigned int *sg_size)
+{
+	int i, n = *sg_num_elem;
+
+	for (i = 0; i < n; ++i) {
+		sk_mem_uncharge(sk, sg[i].length);
+		put_page(sg_page(&sg[i]));
+	}
+	*sg_num_elem = 0;
+	*sg_size = 0;
+}
+
+static void tls_free_both_sg(struct sock *sk)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
+
+	free_sg(sk, ctx->sg_encrypted_data, &ctx->sg_encrypted_num_elem,
+		&ctx->sg_encrypted_size);
+
+	free_sg(sk, ctx->sg_plaintext_data, &ctx->sg_plaintext_num_elem,
+		&ctx->sg_plaintext_size);
+}
+
+static int tls_do_encryption(struct tls_context *tls_ctx,
+			     struct tls_sw_context *ctx, size_t data_len,
+			     gfp_t flags)
+{
+	unsigned int req_size = sizeof(struct aead_request) +
+		crypto_aead_reqsize(ctx->aead_send);
+	struct aead_request *aead_req;
+	int rc;
+
+	aead_req = kmalloc(req_size, flags);
+	if (!aead_req)
+		return -ENOMEM;
+
+	ctx->sg_encrypted_data[0].offset += tls_ctx->prepend_size;
+	ctx->sg_encrypted_data[0].length -= tls_ctx->prepend_size;
+
+	aead_request_set_tfm(aead_req, ctx->aead_send);
+	aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE);
+	aead_request_set_crypt(aead_req, ctx->sg_aead_in, ctx->sg_aead_out,
+			       data_len, tls_ctx->iv);
+	rc = crypto_aead_encrypt(aead_req);
+
+	ctx->sg_encrypted_data[0].offset -= tls_ctx->prepend_size;
+	ctx->sg_encrypted_data[0].length += tls_ctx->prepend_size;
+
+	kfree(aead_req);
+	return rc;
+}
+
+static int tls_push_record(struct sock *sk, int flags,
+			   unsigned char record_type)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
+	int rc;
+
+	sg_mark_end(ctx->sg_plaintext_data + ctx->sg_plaintext_num_elem - 1);
+	sg_mark_end(ctx->sg_encrypted_data + ctx->sg_encrypted_num_elem - 1);
+
+	tls_make_aad(0, ctx->aad_space, ctx->sg_plaintext_size,
+		     tls_ctx->rec_seq, tls_ctx->rec_seq_size,
+		     record_type);
+
+	tls_fill_prepend(tls_ctx,
+			 page_address(sg_page(&ctx->sg_encrypted_data[0])) +
+			 ctx->sg_encrypted_data[0].offset,
+			 ctx->sg_plaintext_size, record_type);
+
+	tls_ctx->pending_open_record_frags = 0;
+	set_bit(TLS_PENDING_CLOSED_RECORD, &tls_ctx->flags);
+
+	rc = tls_do_encryption(tls_ctx, ctx, ctx->sg_plaintext_size,
+			       sk->sk_allocation);
+	if (rc < 0) {
+		/* If we are called from write_space and
+		 * we fail, we need to set this SOCK_NOSPACE
+		 * to trigger another write_space in the future.
+		 */
+		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+		return rc;
+	}
+
+	free_sg(sk, ctx->sg_plaintext_data, &ctx->sg_plaintext_num_elem,
+		&ctx->sg_plaintext_size);
+
+	ctx->sg_encrypted_num_elem = 0;
+	ctx->sg_encrypted_size = 0;
+
+	/* Only pass through MSG_DONTWAIT and MSG_NOSIGNAL flags */
+	rc = tls_push_sg(sk, tls_ctx, ctx->sg_encrypted_data, 0, flags);
+	if (rc < 0 && rc != -EAGAIN)
+		tls_err_abort(sk);
+
+	tls_advance_record_sn(sk, tls_ctx);
+	return rc;
+}
+
+static int tls_sw_push_pending_record(struct sock *sk, int flags)
+{
+	return tls_push_record(sk, flags, TLS_RECORD_TYPE_DATA);
+}
+
+static int zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
+			      int length)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
+	struct page *pages[MAX_SKB_FRAGS];
+
+	size_t offset;
+	ssize_t copied, use;
+	int i = 0;
+	unsigned int size = ctx->sg_plaintext_size;
+	int num_elem = ctx->sg_plaintext_num_elem;
+	int rc = 0;
+	int maxpages;
+
+	while (length > 0) {
+		i = 0;
+		maxpages = ARRAY_SIZE(ctx->sg_plaintext_data) - num_elem;
+		if (maxpages == 0) {
+			rc = -EFAULT;
+			goto out;
+		}
+		copied = iov_iter_get_pages(from, pages,
+					    length,
+					    maxpages, &offset);
+		if (copied <= 0) {
+			rc = -EFAULT;
+			goto out;
+		}
+
+		iov_iter_advance(from, copied);
+
+		length -= copied;
+		size += copied;
+		while (copied) {
+			use = min_t(int, copied, PAGE_SIZE - offset);
+
+			sg_set_page(&ctx->sg_plaintext_data[num_elem],
+				    pages[i], use, offset);
+			sg_unmark_end(&ctx->sg_plaintext_data[num_elem]);
+			sk_mem_charge(sk, use);
+
+			offset = 0;
+			copied -= use;
+
+			++i;
+			++num_elem;
+		}
+	}
+
+out:
+	ctx->sg_plaintext_size = size;
+	ctx->sg_plaintext_num_elem = num_elem;
+	return rc;
+}
+
+static int memcopy_from_iter(struct sock *sk, struct iov_iter *from,
+			     int bytes)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
+	struct scatterlist *sg = ctx->sg_plaintext_data;
+	int copy, i, rc = 0;
+
+	for (i = tls_ctx->pending_open_record_frags;
+	     i < ctx->sg_plaintext_num_elem; ++i) {
+		copy = sg[i].length;
+		if (copy_from_iter(
+				page_address(sg_page(&sg[i])) + sg[i].offset,
+				copy, from) != copy) {
+			rc = -EFAULT;
+			goto out;
+		}
+		bytes -= copy;
+
+		++tls_ctx->pending_open_record_frags;
+
+		if (!bytes)
+			break;
+	}
+
+out:
+	return rc;
+}
+
+int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
+	int ret = 0;
+	int required_size;
+	long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+	bool eor = !(msg->msg_flags & MSG_MORE);
+	size_t try_to_copy, copied = 0;
+	unsigned char record_type = TLS_RECORD_TYPE_DATA;
+	int record_room;
+	bool full_record;
+	int orig_size;
+
+	if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL))
+		return -ENOTSUPP;
+
+	lock_sock(sk);
+
+	if (tls_complete_pending_work(sk, tls_ctx, msg->msg_flags, &timeo))
+		goto send_end;
+
+	if (unlikely(msg->msg_controllen)) {
+		ret = tls_proccess_cmsg(sk, msg, &record_type);
+		if (ret)
+			goto send_end;
+	}
+
+	while (msg_data_left(msg)) {
+		if (sk->sk_err) {
+			ret = sk->sk_err;
+			goto send_end;
+		}
+
+		orig_size = ctx->sg_plaintext_size;
+		full_record = false;
+		try_to_copy = msg_data_left(msg);
+		record_room = TLS_MAX_PAYLOAD_SIZE - ctx->sg_plaintext_size;
+		if (try_to_copy >= record_room) {
+			try_to_copy = record_room;
+			full_record = true;
+		}
+
+		required_size = ctx->sg_plaintext_size + try_to_copy +
+				tls_ctx->overhead_size;
+
+		if (!sk_stream_memory_free(sk))
+			goto wait_for_sndbuf;
+alloc_encrypted:
+		ret = alloc_encrypted_sg(sk, required_size);
+		if (ret) {
+			if (ret != -ENOSPC)
+				goto wait_for_memory;
+
+			/* Adjust try_to_copy according to the amount that was
+			 * actually allocated. The difference is due
+			 * to max sg elements limit
+			 */
+			try_to_copy -= required_size - ctx->sg_encrypted_size;
+			full_record = true;
+		}
+
+		if (full_record || eor) {
+			ret = zerocopy_from_iter(sk, &msg->msg_iter,
+						 try_to_copy);
+			if (ret)
+				goto fallback_to_reg_send;
+
+			copied += try_to_copy;
+			ret = tls_push_record(sk, msg->msg_flags, record_type);
+			if (!ret)
+				continue;
+			if (ret == -EAGAIN)
+				goto send_end;
+
+			copied -= try_to_copy;
+fallback_to_reg_send:
+			iov_iter_revert(&msg->msg_iter,
+					ctx->sg_plaintext_size - orig_size);
+			trim_sg(sk, ctx->sg_plaintext_data,
+				&ctx->sg_plaintext_num_elem,
+				&ctx->sg_plaintext_size,
+				orig_size);
+		}
+
+		required_size = ctx->sg_plaintext_size + try_to_copy;
+alloc_plaintext:
+		ret = alloc_plaintext_sg(sk, required_size);
+		if (ret) {
+			if (ret != -ENOSPC)
+				goto wait_for_memory;
+
+			/* Adjust try_to_copy according to the amount that was
+			 * actually allocated. The difference is due
+			 * to max sg elements limit
+			 */
+			try_to_copy -= required_size - ctx->sg_plaintext_size;
+			full_record = true;
+
+			trim_sg(sk, ctx->sg_encrypted_data,
+				&ctx->sg_encrypted_num_elem,
+				&ctx->sg_encrypted_size,
+				ctx->sg_plaintext_size +
+				tls_ctx->overhead_size);
+		}
+
+		ret = memcopy_from_iter(sk, &msg->msg_iter, try_to_copy);
+		if (ret)
+			goto trim_sgl;
+
+		copied += try_to_copy;
+		if (full_record || eor) {
+push_record:
+			ret = tls_push_record(sk, msg->msg_flags, record_type);
+			if (ret) {
+				if (ret == -ENOMEM)
+					goto wait_for_memory;
+
+				goto send_end;
+			}
+		}
+
+		continue;
+
+wait_for_sndbuf:
+		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+wait_for_memory:
+		ret = sk_stream_wait_memory(sk, &timeo);
+		if (ret) {
+trim_sgl:
+			trim_both_sgl(sk, orig_size);
+			goto send_end;
+		}
+
+		if (tls_is_pending_closed_record(tls_ctx))
+			goto push_record;
+
+		if (ctx->sg_encrypted_size < required_size)
+			goto alloc_encrypted;
+
+		goto alloc_plaintext;
+	}
+
+send_end:
+	ret = sk_stream_error(sk, msg->msg_flags, ret);
+
+	release_sock(sk);
+	return copied ? copied : ret;
+}
+
+int tls_sw_sendpage(struct sock *sk, struct page *page,
+		    int offset, size_t size, int flags)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
+	int ret = 0;
+	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
+	bool eor;
+	size_t orig_size = size;
+	unsigned char record_type = TLS_RECORD_TYPE_DATA;
+	struct scatterlist *sg;
+	bool full_record;
+	int record_room;
+
+	if (flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL |
+		      MSG_SENDPAGE_NOTLAST))
+		return -ENOTSUPP;
+
+	/* No MSG_EOR from splice, only look at MSG_MORE */
+	eor = !(flags & (MSG_MORE | MSG_SENDPAGE_NOTLAST));
+
+	lock_sock(sk);
+
+	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+
+	if (tls_complete_pending_work(sk, tls_ctx, flags, &timeo))
+		goto sendpage_end;
+
+	/* Call the sk_stream functions to manage the sndbuf mem. */
+	while (size > 0) {
+		size_t copy, required_size;
+
+		if (sk->sk_err) {
+			ret = sk->sk_err;
+			goto sendpage_end;
+		}
+
+		full_record = false;
+		record_room = TLS_MAX_PAYLOAD_SIZE - ctx->sg_plaintext_size;
+		copy = size;
+		if (copy >= record_room) {
+			copy = record_room;
+			full_record = true;
+		}
+		required_size = ctx->sg_plaintext_size + copy +
+			      tls_ctx->overhead_size;
+
+		if (!sk_stream_memory_free(sk))
+			goto wait_for_sndbuf;
+alloc_payload:
+		ret = alloc_encrypted_sg(sk, required_size);
+		if (ret) {
+			if (ret != -ENOSPC)
+				goto wait_for_memory;
+
+			/* Adjust copy according to the amount that was
+			 * actually allocated. The difference is due
+			 * to max sg elements limit
+			 */
+			copy -= required_size - ctx->sg_plaintext_size;
+			full_record = true;
+		}
+
+		get_page(page);
+		sg = ctx->sg_plaintext_data + ctx->sg_plaintext_num_elem;
+		sg_set_page(sg, page, copy, offset);
+		ctx->sg_plaintext_num_elem++;
+
+		sk_mem_charge(sk, copy);
+		offset += copy;
+		size -= copy;
+		ctx->sg_plaintext_size += copy;
+		tls_ctx->pending_open_record_frags = ctx->sg_plaintext_num_elem;
+
+		if (full_record || eor ||
+		    ctx->sg_plaintext_num_elem ==
+		    ARRAY_SIZE(ctx->sg_plaintext_data)) {
+push_record:
+			ret = tls_push_record(sk, flags, record_type);
+			if (ret) {
+				if (ret == -ENOMEM)
+					goto wait_for_memory;
+
+				goto sendpage_end;
+			}
+		}
+		continue;
+wait_for_sndbuf:
+		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+wait_for_memory:
+		ret = sk_stream_wait_memory(sk, &timeo);
+		if (ret) {
+			trim_both_sgl(sk, ctx->sg_plaintext_size);
+			goto sendpage_end;
+		}
+
+		if (tls_is_pending_closed_record(tls_ctx))
+			goto push_record;
+
+		goto alloc_payload;
+	}
+
+sendpage_end:
+	if (orig_size > size)
+		ret = orig_size - size;
+	else
+		ret = sk_stream_error(sk, flags, ret);
+
+	release_sock(sk);
+	return ret;
+}
+
+void tls_sw_free_resources(struct sock *sk)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
+
+	if (ctx->aead_send)
+		crypto_free_aead(ctx->aead_send);
+
+	tls_free_both_sg(sk);
+
+	kfree(ctx);
+}
+
+int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx)
+{
+	char keyval[TLS_CIPHER_AES_GCM_128_KEY_SIZE];
+	struct tls_crypto_info *crypto_info;
+	struct tls12_crypto_info_aes_gcm_128 *gcm_128_info;
+	struct tls_sw_context *sw_ctx;
+	u16 nonce_size, tag_size, iv_size, rec_seq_size;
+	char *iv, *rec_seq;
+	int rc = 0;
+
+	if (!ctx) {
+		rc = -EINVAL;
+		goto out;
+	}
+
+	if (ctx->priv_ctx) {
+		rc = -EEXIST;
+		goto out;
+	}
+
+	sw_ctx = kzalloc(sizeof(*sw_ctx), GFP_KERNEL);
+	if (!sw_ctx) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	ctx->priv_ctx = (struct tls_offload_context *)sw_ctx;
+	ctx->free_resources = tls_sw_free_resources;
+
+	crypto_info = &ctx->crypto_send;
+	switch (crypto_info->cipher_type) {
+	case TLS_CIPHER_AES_GCM_128: {
+		nonce_size = TLS_CIPHER_AES_GCM_128_IV_SIZE;
+		tag_size = TLS_CIPHER_AES_GCM_128_TAG_SIZE;
+		iv_size = TLS_CIPHER_AES_GCM_128_IV_SIZE;
+		iv = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->iv;
+		rec_seq_size = TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE;
+		rec_seq =
+		 ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->rec_seq;
+		gcm_128_info =
+			(struct tls12_crypto_info_aes_gcm_128 *)crypto_info;
+		break;
+	}
+	default:
+		rc = -EINVAL;
+		goto out;
+	}
+
+	ctx->prepend_size = TLS_HEADER_SIZE + nonce_size;
+	ctx->tag_size = tag_size;
+	ctx->overhead_size = ctx->prepend_size + ctx->tag_size;
+	ctx->iv_size = iv_size;
+	ctx->iv = kmalloc(iv_size + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
+			  GFP_KERNEL);
+	if (!ctx->iv) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	memcpy(ctx->iv, gcm_128_info->salt, TLS_CIPHER_AES_GCM_128_SALT_SIZE);
+	memcpy(ctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, iv, iv_size);
+	ctx->rec_seq_size = rec_seq_size;
+	ctx->rec_seq = kmalloc(rec_seq_size, GFP_KERNEL);
+	if (!ctx->rec_seq) {
+		rc = -ENOMEM;
+		goto free_iv;
+	}
+	memcpy(ctx->rec_seq, rec_seq, rec_seq_size);
+
+	sg_init_table(sw_ctx->sg_encrypted_data,
+		      ARRAY_SIZE(sw_ctx->sg_encrypted_data));
+	sg_init_table(sw_ctx->sg_plaintext_data,
+		      ARRAY_SIZE(sw_ctx->sg_plaintext_data));
+
+	sg_init_table(sw_ctx->sg_aead_in, 2);
+	sg_set_buf(&sw_ctx->sg_aead_in[0], sw_ctx->aad_space,
+		   sizeof(sw_ctx->aad_space));
+	sg_unmark_end(&sw_ctx->sg_aead_in[1]);
+	sg_chain(sw_ctx->sg_aead_in, 2, sw_ctx->sg_plaintext_data);
+	sg_init_table(sw_ctx->sg_aead_out, 2);
+	sg_set_buf(&sw_ctx->sg_aead_out[0], sw_ctx->aad_space,
+		   sizeof(sw_ctx->aad_space));
+	sg_unmark_end(&sw_ctx->sg_aead_out[1]);
+	sg_chain(sw_ctx->sg_aead_out, 2, sw_ctx->sg_encrypted_data);
+
+	if (!sw_ctx->aead_send) {
+		sw_ctx->aead_send = crypto_alloc_aead("gcm(aes)", 0, 0);
+		if (IS_ERR(sw_ctx->aead_send)) {
+			rc = PTR_ERR(sw_ctx->aead_send);
+			sw_ctx->aead_send = NULL;
+			goto free_rec_seq;
+		}
+	}
+
+	ctx->push_pending_record = tls_sw_push_pending_record;
+
+	memcpy(keyval, gcm_128_info->key, TLS_CIPHER_AES_GCM_128_KEY_SIZE);
+
+	rc = crypto_aead_setkey(sw_ctx->aead_send, keyval,
+				TLS_CIPHER_AES_GCM_128_KEY_SIZE);
+	if (rc)
+		goto free_aead;
+
+	rc = crypto_aead_setauthsize(sw_ctx->aead_send, ctx->tag_size);
+	if (!rc)
+		goto out;
+
+free_aead:
+	crypto_free_aead(sw_ctx->aead_send);
+	sw_ctx->aead_send = NULL;
+free_rec_seq:
+	kfree(ctx->rec_seq);
+	ctx->rec_seq = NULL;
+free_iv:
+	kfree(ctx->iv);
+	ctx->iv = NULL;
+out:
+	return rc;
+}