Message-ID: <ac7783121ef9442741d67aca5d170f02d851ae03.1448299690.git.davejwatson@fb.com>
Date:	Mon, 23 Nov 2015 09:43:02 -0800
From:	Dave Watson <davejwatson@...com>
To:	Tom Herbert <tom@...bertland.com>, <netdev@...r.kernel.org>,
	<davem@...emloft.net>,
	Sowmini Varadhan <sowmini.varadhan@...cle.com>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	<linux-crypto@...r.kernel.org>
CC:	<linux-kernel@...r.kernel.org>, <kernel-team@...com>
Subject: [RFC PATCH 2/2] Crypto kernel tls socket

Userspace crypto interface for TLS.  Currently supports gcm(aes) 128bit only,
however the interface is the same as the rest of the SOCK_ALG interface, so it
should be possible to add more without any user interface changes.

Currently gcm(aes) represents ~80% of our SSL connections.

Userspace interface:

1) A transform and op socket are created using the userspace crypto interface
2) Setsockopt ALG_SET_AUTHSIZE is called
3) Setsockopt ALG_SET_KEY is called twice, since we need both send/recv keys
4) ALG_SET_IV cmsgs are sent twice, since we need both send/recv IVs.
   To support userspace heartbeats, changeciphersuite, etc, we would also need
   to get these back out, use them, then reset them via CMSG.
5) ALG_SET_OP cmsg is overloaded to mean FD to read/write from.

Example program:

https://github.com/djwatson/ktls

At a high level, this could be implemented on TCP sockets directly instead with
various tradeoffs.

The userspace crypto interface might benefit from some interface
tweaking to deal with multiple keys / ivs better.  The crypto accept()
op socket interface isn't a great fit, since there are never multiple
parallel operations.

There's also some questions around using skbuffs instead of scatterlists for
send/recv, and if we are buffering on recv, when we should be decrypting the
data.
---
 crypto/Kconfig     |   12 +
 crypto/Makefile    |    1 +
 crypto/algif_tls.c | 1233 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1246 insertions(+)
 create mode 100644 crypto/algif_tls.c

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 7240821..c15638a 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1639,6 +1639,18 @@ config CRYPTO_USER_API_AEAD
 	  This option enables the user-spaces interface for AEAD
 	  cipher algorithms.

+config CRYPTO_USER_API_TLS
+	tristate "User-space interface for TLS net sockets"
+	depends on NET
+	select CRYPTO_AEAD
+	select CRYPTO_USER_API
+	help
+	  This option enables kernel TLS socket framing
+	  cipher algorithms.  TLS framing is added/removed and
+          chained to a TCP socket.  Handshake is done in
+          userspace.
+
+
 config CRYPTO_HASH_INFO
 	bool

diff --git a/crypto/Makefile b/crypto/Makefile
index f7aba92..fc26012 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -121,6 +121,7 @@ obj-$(CONFIG_CRYPTO_USER_API_HASH) += algif_hash.o
 obj-$(CONFIG_CRYPTO_USER_API_SKCIPHER) += algif_skcipher.o
 obj-$(CONFIG_CRYPTO_USER_API_RNG) += algif_rng.o
 obj-$(CONFIG_CRYPTO_USER_API_AEAD) += algif_aead.o
+obj-$(CONFIG_CRYPTO_USER_API_TLS) += algif_tls.o

 #
 # generic algorithms and the async_tx api
diff --git a/crypto/algif_tls.c b/crypto/algif_tls.c
new file mode 100644
index 0000000..123ade3
--- /dev/null
+++ b/crypto/algif_tls.c
@@ -0,0 +1,1233 @@
+/*
+ * algif_tls: User-space interface for TLS
+ *
+ * Copyright (C) 2015, Dave Watson <davejwatson@...com>
+ *
+ * This file provides the user-space API for AEAD ciphers.
+ *
+ * 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/aead.h>
+#include <crypto/if_alg.h>
+#include <linux/init.h>
+#include <linux/file.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>
+#include <net/tcp.h>
+
+#define TLS_HEADER_SIZE 13
+#define TLS_TAG_SIZE 16
+#define TLS_IV_SIZE 8
+#define TLS_PADDED_AADLEN 16
+#define TLS_MAX_MESSAGE_LEN (1 << 14)
+
+/* Bytes not included in tls msg size field */
+#define TLS_FRAMING_SIZE 5
+
+#define TLS_APPLICATION_DATA_MSG 0x17
+#define TLS_VERSION 3
+
+struct tls_tfm_pair {
+	struct crypto_aead *tfm_send;
+	struct crypto_aead *tfm_recv;
+	int cur_setkey;
+};
+
+static struct workqueue_struct *tls_wq;
+
+struct tls_sg_list {
+	unsigned int cur;
+	struct scatterlist sg[ALG_MAX_PAGES];
+};
+
+#define RSGL_MAX_ENTRIES ALG_MAX_PAGES
+
+struct tls_ctx {
+	/* Send and encrypted transmit buffers */
+	struct tls_sg_list tsgl;
+	struct scatterlist tcsgl[ALG_MAX_PAGES];
+
+	/* Encrypted receive and receive buffers. */
+	struct tls_sg_list rcsgl;
+	struct af_alg_sgl rsgl[RSGL_MAX_ENTRIES];
+
+	/* Sequence numbers. */
+	int iv_set;
+	void *iv_send;
+	void *iv_recv;
+
+	struct af_alg_completion completion;
+
+	/* Bytes to send */
+	unsigned long used;
+
+	/* padded */
+	size_t aead_assoclen;
+	/* unpadded */
+	size_t assoclen;
+	struct aead_request aead_req;
+	struct aead_request aead_resp;
+
+	bool more;
+	bool merge;
+
+	/* Chained TCP socket */
+	struct sock *sock;
+	struct socket *socket;
+
+	void (*save_data_ready)(struct sock *sk);
+	void (*save_write_space)(struct sock *sk);
+	void (*save_state_change)(struct sock *sk);
+	struct work_struct tx_work;
+	struct work_struct rx_work;
+
+	/* This socket for use with above callbacks */
+	struct sock *alg_sock;
+
+	/* Send buffer tracking */
+	int page_to_send;
+	int tcsgl_size;
+
+	/* Recv buffer tracking */
+	int recv_wanted;
+	int recved_len;
+
+	/* Receive AAD. */
+	unsigned char buf[24];
+};
+
+static void increment_seqno(u64 *seqno)
+{
+	u64 seq_h = be64_to_cpu(*seqno);
+
+	seq_h++;
+	*seqno = cpu_to_be64(seq_h);
+}
+
+static int do_tls_kernel_sendpage(struct sock *sk);
+
+static int tls_wait_for_data(struct sock *sk, unsigned flags)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_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->recved_len == ctx->recv_wanted)) {
+			err = 0;
+			break;
+		}
+	}
+	finish_wait(sk_sleep(sk), &wait);
+
+	clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+
+	return err;
+}
+
+static int tls_wait_for_write_space(struct sock *sk, unsigned flags)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_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->page_to_send)) {
+			err = 0;
+			break;
+		}
+	}
+	finish_wait(sk_sleep(sk), &wait);
+
+	clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+
+	return err;
+}
+
+static inline int tls_sndbuf(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_ctx *ctx = ask->private;
+
+	return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
+			  ctx->used, 0);
+}
+
+static inline bool tls_writable(struct sock *sk)
+{
+	return tls_sndbuf(sk) >= PAGE_SIZE;
+}
+
+
+static void tls_put_sgl(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_ctx *ctx = ask->private;
+	struct tls_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);
+	}
+	sg_init_table(sg, ALG_MAX_PAGES);
+	sgl->cur = 0;
+	ctx->used = 0;
+	ctx->more = 0;
+	ctx->merge = 0;
+}
+
+static void tls_wmem_wakeup(struct sock *sk)
+{
+	struct socket_wq *wq;
+
+	if (!tls_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 void tls_put_rcsgl(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_ctx *ctx = ask->private;
+	struct tls_sg_list *sgl = &ctx->rcsgl;
+	int i;
+
+	for (i = 0; i < sgl->cur; i++)
+		put_page(sg_page(&sgl->sg[i]));
+	sgl->cur = 0;
+	sg_init_table(&sgl->sg[0], ALG_MAX_PAGES);
+}
+
+
+static void tls_sock_state_change(struct sock *sk)
+{
+	struct tls_ctx *ctx;
+
+	ctx = (struct tls_ctx *)sk->sk_user_data;
+
+	switch (sk->sk_state) {
+	case TCP_CLOSE:
+	case TCP_CLOSE_WAIT:
+	case TCP_ESTABLISHED:
+		ctx->alg_sock->sk_state = sk->sk_state;
+		ctx->alg_sock->sk_state_change(ctx->alg_sock);
+		tls_wmem_wakeup(ctx->alg_sock);
+
+		break;
+	default:	/* Everything else is uninteresting */
+		break;
+	}
+}
+
+/* Both socket  lock held */
+static ssize_t tls_socket_splice(struct sock *sk,
+				struct pipe_inode_info *pipe,
+				struct splice_pipe_desc *spd) {
+	struct tls_ctx *ctx = (struct tls_ctx *)pipe;
+	struct tls_sg_list *sgl = &ctx->rcsgl;
+
+	unsigned int spd_pages = spd->nr_pages;
+	int ret = 0;
+	int page_nr = 0;
+
+	while (spd->nr_pages > 0) {
+		if (sgl->cur < ALG_MAX_PAGES) {
+			struct scatterlist *sg = &sgl->sg[sgl->cur];
+
+			sg_assign_page(sg, spd->pages[page_nr]);
+			sg->offset = spd->partial[page_nr].offset;
+			sg->length = spd->partial[page_nr].len;
+			sgl->cur++;
+
+			ret += spd->partial[page_nr].len;
+			page_nr++;
+
+			--spd->nr_pages;
+		} else {
+			sk->sk_err = -ENOMEM;
+			break;
+		}
+	}
+
+	while (page_nr < spd_pages)
+		spd->spd_release(spd, page_nr++);
+
+	ctx->recved_len += ret;
+
+	if (ctx->recved_len == ctx->recv_wanted || sk->sk_err)
+		tls_wmem_wakeup(ctx->alg_sock);
+
+	return ret;
+}
+
+/* Both socket  lock held */
+static int tls_tcp_recv(read_descriptor_t *desc, struct sk_buff *skb,
+			unsigned int offset, size_t len)
+{
+	int ret;
+
+	ret = skb_splice_bits(skb, skb->sk, offset, desc->arg.data,
+			min(desc->count, len),
+			0, tls_socket_splice);
+	if (ret > 0)
+		desc->count -= ret;
+
+	return ret;
+}
+
+static int tls_tcp_read_sock(struct tls_ctx *ctx)
+{
+	struct sock *sk = ctx->alg_sock;
+
+	struct msghdr msg = {};
+	struct kvec iov;
+	read_descriptor_t desc;
+
+	desc.arg.data = ctx;
+	desc.error = 0;
+
+	lock_sock(sk);
+
+	iov.iov_base = ctx->buf;
+	iov.iov_len = TLS_HEADER_SIZE;
+
+	if (ctx->recv_wanted == -1) {
+		unsigned int encrypted_size = 0;
+
+		/* Peek at framing.
+		 *
+		 * We only handle TLS message type 0x17, application_data.
+		 *
+		 * Otherwise set an error on the socket and let
+		 * userspace handle the message types
+		 * change_cipher_spec, alert, handshake
+		 *
+		 */
+		int bytes = kernel_recvmsg(ctx->socket, &msg, &iov, 1,
+					iov.iov_len, MSG_PEEK | MSG_DONTWAIT);
+
+		if (bytes <= 0)
+			goto unlock;
+
+		if (ctx->buf[0] != TLS_APPLICATION_DATA_MSG) {
+			sk->sk_err = -EBADMSG;
+			desc.error = sk->sk_err;
+			goto unlock;
+		}
+
+		if (bytes < TLS_HEADER_SIZE)
+			goto unlock;
+
+
+		encrypted_size = ctx->buf[4] | (ctx->buf[3] << 8);
+
+		/* Verify encrypted size looks sane */
+		if (encrypted_size > TLS_MAX_MESSAGE_LEN + TLS_TAG_SIZE +
+			TLS_HEADER_SIZE - TLS_FRAMING_SIZE) {
+			sk->sk_err = -EINVAL;
+			desc.error = sk->sk_err;
+			goto unlock;
+		}
+		/* encrypted_size field doesn't include 5 bytes of framing */
+		ctx->recv_wanted = encrypted_size + TLS_FRAMING_SIZE;
+
+		/* Flush header bytes.  We peeked at before, we will
+		 * handle this message type
+		 */
+		bytes = kernel_recvmsg(ctx->socket, &msg, &iov, 1,
+				iov.iov_len, MSG_DONTWAIT);
+		WARN_ON(bytes != TLS_HEADER_SIZE);
+		ctx->recved_len = TLS_HEADER_SIZE;
+	}
+
+	if (ctx->recv_wanted <= 0)
+		goto unlock;
+
+	desc.count = ctx->recv_wanted - ctx->recved_len;
+
+	if (desc.count > 0) {
+		lock_sock(ctx->sock);
+
+		tcp_read_sock(ctx->sock, &desc, tls_tcp_recv);
+
+		release_sock(ctx->sock);
+	}
+
+unlock:
+	if (desc.error)
+		tls_wmem_wakeup(ctx->alg_sock);
+
+	release_sock(sk);
+
+	return desc.error;
+}
+
+static void tls_tcp_data_ready(struct sock *sk)
+{
+	struct tls_ctx *ctx;
+
+	read_lock_bh(&sk->sk_callback_lock);
+
+	ctx = (struct tls_ctx *)sk->sk_user_data;
+
+	queue_work(tls_wq, &ctx->rx_work);
+
+	read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void tls_tcp_write_space(struct sock *sk)
+{
+	struct tls_ctx *ctx;
+
+	read_lock_bh(&sk->sk_callback_lock);
+
+	ctx = (struct tls_ctx *)sk->sk_user_data;
+
+	queue_work(tls_wq, &ctx->tx_work);
+
+	read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void tls_rx_work(struct work_struct *w)
+{
+	struct tls_ctx *ctx = container_of(w, struct tls_ctx, rx_work);
+
+	tls_tcp_read_sock(ctx);
+}
+
+static void tls_tx_work(struct work_struct *w)
+{
+	struct tls_ctx *ctx = container_of(w, struct tls_ctx, tx_work);
+	struct sock *sk = ctx->alg_sock;
+	int err;
+
+	lock_sock(sk);
+
+	err = do_tls_kernel_sendpage(sk);
+	if (err < 0) {
+		/* Hard failure in write, report error on KCM socket */
+		pr_warn("TLS: Hard failure on do_tls_sendpage %d\n", err);
+		sk->sk_err = -err;
+		tls_wmem_wakeup(sk);
+		goto out;
+	}
+
+out:
+	release_sock(sk);
+}
+
+static int do_tls_kernel_sendpage(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_ctx *ctx = ask->private;
+	int err = 0;
+	int i;
+
+	if (ctx->page_to_send == 0)
+		return err;
+	for (; ctx->page_to_send < ctx->tcsgl_size; ctx->page_to_send++) {
+		int flags = MSG_DONTWAIT;
+
+		if (ctx->page_to_send != ctx->tcsgl_size - 1)
+			flags |= MSG_MORE;
+		err = kernel_sendpage(ctx->sock->sk_socket,
+				sg_page(&ctx->tcsgl[ctx->page_to_send]),
+				ctx->tcsgl[ctx->page_to_send].offset,
+				ctx->tcsgl[ctx->page_to_send].length,
+				flags);
+		if (err <= 0) {
+			if (err == -EAGAIN) {
+				/* Don't forward EAGAIN */
+				err = 0;
+				goto out;
+			}
+			goto out;
+		}
+	}
+
+	ctx->page_to_send = 0;
+
+	increment_seqno(ctx->iv_send);
+
+
+	for (i = 1; i < ctx->tcsgl_size; i++)
+		put_page(sg_page(&ctx->tcsgl[i]));
+
+	tls_wmem_wakeup(sk);
+out:
+
+	return err;
+}
+
+static int do_tls_sendpage(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_ctx *ctx = ask->private;
+	struct tls_sg_list *sgl = &ctx->tsgl;
+
+	int used = ctx->used;
+
+	unsigned ivsize =
+		crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req));
+	int encrypted_size = ivsize + used +
+		crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
+
+	/* Ensure enough space in sg list for tag. */
+	struct scatterlist *sg = &ctx->tcsgl[1];
+	int bytes_needed = used + TLS_HEADER_SIZE + TLS_TAG_SIZE;
+	int err = -ENOMEM;
+
+	struct page *p;
+	unsigned char *framing;
+	unsigned char aad[ctx->aead_assoclen];
+	struct scatterlist sgaad[2];
+
+	WARN_ON(used > TLS_MAX_MESSAGE_LEN);
+
+	/* Framing will be put in first sg */
+	ctx->tcsgl_size = 1;
+
+	do {
+		sg_assign_page(sg, alloc_page(GFP_KERNEL));
+		if (!sg_page(sg))
+			goto unlock;
+
+		sg_unmark_end(sg);
+		sg->offset = 0;
+		sg->length = PAGE_SIZE;
+		if (bytes_needed < PAGE_SIZE)
+			sg->length = bytes_needed;
+
+		ctx->tcsgl_size++;
+		sg = &ctx->tcsgl[ctx->tcsgl_size];
+		bytes_needed -= PAGE_SIZE;
+	} while (bytes_needed > 0);
+
+	p = sg_page(&ctx->tcsgl[1]);
+
+	sg = &ctx->tcsgl[0];
+
+	sg->offset = 0;
+	sg->length = TLS_PADDED_AADLEN + TLS_IV_SIZE;
+	sg_assign_page(sg, p);
+
+	sg = &ctx->tcsgl[1];
+	sg->offset = TLS_HEADER_SIZE;
+	sg->length = sg->length - TLS_HEADER_SIZE;
+
+	sg_mark_end(&ctx->tcsgl[ctx->tcsgl_size - 1]);
+	framing = page_address(p);
+
+	/* Hardcoded to TLS 1.2 */
+	memset(framing, 0, ctx->aead_assoclen);
+	framing[0] = TLS_APPLICATION_DATA_MSG;
+	framing[1] = TLS_VERSION;
+	framing[2] = TLS_VERSION;
+	framing[3] = encrypted_size >> 8;
+	framing[4] = encrypted_size & 0xff;
+	/* Per spec, iv_send can be used as nonce */
+	memcpy(framing + 5, ctx->iv_send, TLS_IV_SIZE);
+
+	memset(aad, 0, ctx->aead_assoclen);
+	memcpy(aad, ctx->iv_send, TLS_IV_SIZE);
+
+	aad[8] = TLS_APPLICATION_DATA_MSG;
+	aad[9] = TLS_VERSION;
+	aad[10] = TLS_VERSION;
+	aad[11] = used >> 8;
+	aad[12] = used & 0xff;
+
+	sg_set_buf(&sgaad[0], aad, ctx->aead_assoclen);
+	sg_unmark_end(sgaad);
+	sg_chain(sgaad, 2, sgl->sg);
+
+	sg_mark_end(sgl->sg + sgl->cur - 1);
+	aead_request_set_crypt(&ctx->aead_req, sgaad, ctx->tcsgl,
+			       used, ctx->iv_send);
+	aead_request_set_ad(&ctx->aead_req, ctx->assoclen);
+
+	err = af_alg_wait_for_completion(crypto_aead_encrypt(&ctx->aead_req),
+					 &ctx->completion);
+
+	if (err) {
+		/* EBADMSG implies a valid cipher operation took place */
+		if (err == -EBADMSG)
+			tls_put_sgl(sk);
+		goto unlock;
+	}
+
+	ctx->tcsgl[1].length += TLS_HEADER_SIZE;
+	ctx->tcsgl[1].offset = 0;
+
+	ctx->page_to_send = 1;
+
+	tls_put_sgl(sk);
+
+	err = do_tls_kernel_sendpage(sk);
+
+unlock:
+
+	return err;
+}
+
+static int tls_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_ctx *ctx = ask->private;
+	struct tls_sg_list *sgl = &ctx->tsgl;
+	unsigned ivsize =
+		crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req));
+	struct af_alg_control con = {};
+	long copied = 0;
+	bool init = 0;
+	int err = -EINVAL;
+
+	struct socket *csock = NULL;
+	struct sock *csk = NULL;
+
+	if (msg->msg_controllen) {
+		init = 1;
+		err = af_alg_cmsg_send(msg, &con);
+		if (err)
+			return err;
+
+		if (!ctx->sock) {
+			if (!con.op) {
+				err = -EINVAL;
+				return err;
+			}
+			csock = sockfd_lookup(con.op, &err);
+			if (!csock)
+				return -ENOENT;
+			csk = csock->sk;
+			ctx->sock = csk;
+			ctx->socket = csock;
+			ctx->alg_sock = sk;
+			if (!ctx->sock) {
+				err = -EINVAL;
+				fput(csock->file);
+				return err;
+			}
+		}
+
+		if (con.iv && con.iv->ivlen != ivsize)
+			return -EINVAL;
+	}
+
+	lock_sock(sk);
+
+	if (!ctx->more && ctx->used)
+		goto unlock;
+
+	if (init) {
+		if (con.iv) {
+			if (ctx->iv_set == 0) {
+				ctx->iv_set = 1;
+				memcpy(ctx->iv_send, con.iv->iv, ivsize);
+			} else {
+				memcpy(ctx->iv_recv, con.iv->iv, ivsize);
+			}
+		}
+
+		if (con.aead_assoclen) {
+			ctx->assoclen = con.aead_assoclen;
+			/* Pad out assoclen to 4-byte boundary */
+			ctx->aead_assoclen = (con.aead_assoclen + 3) & ~3;
+		}
+
+		if (csk) {
+			write_lock_bh(&csk->sk_callback_lock);
+			ctx->save_data_ready = csk->sk_data_ready;
+			ctx->save_write_space = csk->sk_write_space;
+			ctx->save_state_change = csk->sk_state_change;
+			csk->sk_user_data = ctx;
+			csk->sk_data_ready = tls_tcp_data_ready;
+			csk->sk_write_space = tls_tcp_write_space;
+			csk->sk_state_change = tls_sock_state_change;
+			write_unlock_bh(&csk->sk_callback_lock);
+		}
+	}
+
+	if (sk->sk_err)
+		goto out_error;
+
+	while (size) {
+		unsigned long 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);
+
+			if (ctx->page_to_send != 0) {
+				err = tls_wait_for_write_space(
+					sk, msg->msg_flags);
+				if (err)
+					goto unlock;
+			}
+
+			if (ctx->used + len > TLS_MAX_MESSAGE_LEN) {
+				err = do_tls_sendpage(sk);
+				if (err < 0)
+					goto unlock;
+
+				continue;
+			}
+
+			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 (!tls_writable(sk)) {
+			/* user space sent too much data */
+			tls_put_sgl(sk);
+			err = -EMSGSIZE;
+			goto unlock;
+		}
+
+		/* allocate a new page */
+		len = min_t(unsigned long, size, tls_sndbuf(sk));
+		while (len) {
+			int plen = 0;
+
+			if (sgl->cur >= ALG_MAX_PAGES) {
+				tls_put_sgl(sk);
+				err = -E2BIG;
+				goto unlock;
+			}
+
+			sg = sgl->sg + sgl->cur;
+			plen = min_t(int, len, PAGE_SIZE);
+
+			if (ctx->page_to_send != 0) {
+				err = tls_wait_for_write_space(
+					sk, msg->msg_flags);
+				if (err)
+					goto unlock;
+			}
+
+			if (ctx->used + plen > TLS_MAX_MESSAGE_LEN) {
+				err = do_tls_sendpage(sk);
+				if (err < 0)
+					goto unlock;
+				continue;
+			}
+
+			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 && ctx->used < TLS_MAX_MESSAGE_LEN)
+		goto unlock;
+
+	if (ctx->page_to_send != 0) {
+		err = tls_wait_for_write_space(sk, msg->msg_flags);
+		if (err)
+			goto unlock;
+	}
+
+	err = do_tls_sendpage(sk);
+
+unlock:
+	release_sock(sk);
+
+	return err ?: copied;
+
+out_error:
+	err = sk_stream_error(sk, msg->msg_flags, err);
+	release_sock(sk);
+
+	return err;
+}
+
+static ssize_t tls_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 tls_ctx *ctx = ask->private;
+	struct tls_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 (sk->sk_err)
+		goto out_error;
+
+	if (ctx->page_to_send != 0) {
+		err = tls_wait_for_write_space(sk, flags);
+		if (err)
+			goto unlock;
+	}
+
+	if (size + ctx->used > TLS_MAX_MESSAGE_LEN) {
+		err = do_tls_sendpage(sk);
+		if (err < 0)
+			goto unlock;
+		err = -EINVAL;
+	}
+
+	if (!ctx->more && ctx->used)
+		goto unlock;
+
+	if (!size)
+		goto done;
+
+	if (!tls_writable(sk)) {
+		/* user space sent too much data */
+		tls_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 && ctx->used < TLS_MAX_MESSAGE_LEN)
+		goto unlock;
+
+	err = do_tls_sendpage(sk);
+
+unlock:
+	release_sock(sk);
+
+	return err < 0 ? err : size;
+
+out_error:
+	err = sk_stream_error(sk, flags, err);
+	release_sock(sk);
+
+	return err;
+}
+
+static int tls_recvmsg(struct socket *sock, struct msghdr *msg,
+		size_t ignored, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_ctx *ctx = ask->private;
+	unsigned int i = 0;
+	int err = -EINVAL;
+	size_t outlen = 0;
+	size_t usedpages = 0;
+	unsigned int cnt = 0;
+
+	char aad_unneeded[ctx->aead_assoclen];
+	struct scatterlist outaad[2];
+
+	struct tls_sg_list *sgl = &ctx->rcsgl;
+	struct scatterlist aadsg[2];
+
+	char buf[11];
+	int used;
+	char *aad;
+
+	char nonce[TLS_IV_SIZE];
+
+	/* Limit number of IOV blocks to be accessed below */
+	if (msg->msg_iter.nr_segs > RSGL_MAX_ENTRIES)
+		return -ENOMSG;
+
+	tls_tcp_read_sock(ctx);
+
+	lock_sock(sk);
+
+	if (sk->sk_err)
+		goto out_error;
+
+	if (ctx->recved_len != ctx->recv_wanted) {
+		err = tls_wait_for_data(sk, flags);
+		if (err)
+			goto unlock;
+	}
+
+	sg_set_buf(outaad, aad_unneeded, ctx->aead_assoclen);
+	sg_unmark_end(outaad);
+	sg_chain(outaad, 2, &ctx->rsgl[0].sg[0]);
+
+	outlen = ctx->recv_wanted - TLS_FRAMING_SIZE - ctx->aead_assoclen;
+
+	/* 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));
+
+		/* make one iovec available as scatterlist */
+		err = af_alg_make_sg(&ctx->rsgl[cnt], &msg->msg_iter,
+				     seglen);
+		if (err < 0)
+			goto unlock;
+		usedpages += err;
+		/* chain the new scatterlist with previous one */
+		if (cnt)
+			af_alg_link_sg(&ctx->rsgl[cnt-1], &ctx->rsgl[cnt]);
+
+		/* we do not need more iovecs as we have sufficient memory */
+		if (outlen <= usedpages)
+			break;
+		iov_iter_advance(&msg->msg_iter, err);
+		cnt++;
+	}
+
+	err = -EINVAL;
+
+	/* ensure output buffer is sufficiently large */
+	if (usedpages < outlen)
+		goto unlock;
+
+	memset(buf, 0, sizeof(buf));
+
+	used = ctx->recv_wanted - ctx->aead_assoclen - TLS_FRAMING_SIZE;
+
+	aad = ctx->buf;
+
+	sg_set_buf(aadsg, ctx->buf, ctx->aead_assoclen);
+	sg_unmark_end(aadsg);
+	sg_chain(aadsg, 2, sgl->sg);
+
+	memcpy(nonce, aad + TLS_FRAMING_SIZE, TLS_IV_SIZE);
+	memcpy(aad, ctx->iv_recv, TLS_IV_SIZE);
+
+	aad[8] = TLS_APPLICATION_DATA_MSG;
+	aad[9] = TLS_VERSION;
+	aad[10] = TLS_VERSION;
+	aad[11] = used >> 8;
+	aad[12] = used & 0xff;
+
+	sg_mark_end(sgl->sg + sgl->cur - 1);
+	aead_request_set_crypt(&ctx->aead_resp, aadsg, outaad,
+			ctx->recv_wanted + TLS_TAG_SIZE
+			- TLS_FRAMING_SIZE - ctx->aead_assoclen,
+			nonce);
+	aead_request_set_ad(&ctx->aead_resp, ctx->assoclen);
+
+	err = af_alg_wait_for_completion(crypto_aead_decrypt(&ctx->aead_resp),
+	&ctx->completion);
+
+	if (err) {
+		/* EBADMSG implies a valid cipher operation took place */
+		goto unlock;
+	} else {
+		ctx->recv_wanted = -1;
+		ctx->recved_len = 0;
+	}
+
+	increment_seqno(ctx->iv_recv);
+
+	err = 0;
+
+unlock:
+	tls_put_rcsgl(sk);
+
+	for (i = 0; i < cnt; i++)
+		af_alg_free_sg(&ctx->rsgl[i]);
+
+	queue_work(tls_wq, &ctx->rx_work);
+	release_sock(sk);
+
+	return err ? err : outlen;
+
+out_error:
+	err = sk_stream_error(sk, msg->msg_flags, err);
+	release_sock(sk);
+
+	return err;
+}
+
+
+static struct proto_ops algif_tls_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	=	tls_sendmsg,
+	.sendpage	=	tls_sendpage,
+	.recvmsg	=	tls_recvmsg,
+	.poll		=	sock_no_poll,
+};
+
+static void *tls_bind(const char *name, u32 type, u32 mask)
+{
+	struct tls_tfm_pair *pair = kmalloc(sizeof(struct tls_tfm_pair),
+					GFP_KERNEL);
+
+	if (!pair)
+		return NULL;
+	pair->tfm_send = crypto_alloc_aead(name, type, mask);
+	if (!pair->tfm_send)
+		goto error;
+	pair->tfm_recv = crypto_alloc_aead(name, type, mask);
+	if (!pair->tfm_recv)
+		goto error;
+
+	pair->cur_setkey = 0;
+
+	return pair;
+
+error:
+	if (pair->tfm_send)
+		crypto_free_aead(pair->tfm_send);
+	if (pair->tfm_recv)
+		crypto_free_aead(pair->tfm_recv);
+	kfree(pair);
+
+	return NULL;
+}
+
+static void tls_release(void *private)
+{
+	struct tls_tfm_pair *pair = private;
+
+	if (pair) {
+		if (pair->tfm_send)
+			crypto_free_aead(pair->tfm_send);
+		if (pair->tfm_recv)
+			crypto_free_aead(pair->tfm_recv);
+		kfree(private);
+	}
+}
+
+static int tls_setauthsize(void *private, unsigned int authsize)
+{
+	struct tls_tfm_pair *pair = private;
+
+	crypto_aead_setauthsize(pair->tfm_recv, authsize);
+	return crypto_aead_setauthsize(pair->tfm_send, authsize);
+}
+
+static int tls_setkey(void *private, const u8 *key, unsigned int keylen)
+{
+	struct tls_tfm_pair *pair = private;
+
+	if (pair->cur_setkey == 0) {
+		pair->cur_setkey = 1;
+		return crypto_aead_setkey(pair->tfm_send, key, keylen);
+	} else {
+		return crypto_aead_setkey(pair->tfm_recv, key, keylen);
+	}
+}
+
+static void tls_sock_destruct(struct sock *sk)
+{
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_ctx *ctx = ask->private;
+	unsigned int ivlen = crypto_aead_ivsize(
+				crypto_aead_reqtfm(&ctx->aead_req));
+
+
+
+	cancel_work_sync(&ctx->tx_work);
+	cancel_work_sync(&ctx->rx_work);
+
+	/* Stop getting callbacks from TCP socket. */
+	write_lock_bh(&ctx->sock->sk_callback_lock);
+	if (ctx->sock->sk_user_data) {
+		ctx->sock->sk_user_data = NULL;
+		ctx->sock->sk_data_ready = ctx->save_data_ready;
+		ctx->sock->sk_write_space = ctx->save_write_space;
+		ctx->sock->sk_state_change = ctx->save_state_change;
+	}
+	write_unlock_bh(&ctx->sock->sk_callback_lock);
+
+	tls_put_sgl(sk);
+	sock_kzfree_s(sk, ctx->iv_send, ivlen);
+	sock_kzfree_s(sk, ctx->iv_recv, ivlen);
+	sock_kfree_s(sk, ctx, sizeof(*ctx));
+	af_alg_release_parent(sk);
+}
+
+static int tls_accept_parent(void *private, struct sock *sk)
+{
+	struct tls_ctx *ctx;
+	struct alg_sock *ask = alg_sk(sk);
+	struct tls_tfm_pair *pair = private;
+
+	unsigned int len = sizeof(*ctx);
+	unsigned int ivlen = crypto_aead_ivsize(pair->tfm_send);
+
+	ctx = sock_kmalloc(sk, len, GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+	memset(ctx, 0, len);
+
+	ctx->iv_send = sock_kmalloc(sk, ivlen, GFP_KERNEL);
+	if (!ctx->iv_send) {
+		sock_kfree_s(sk, ctx, len);
+		return -ENOMEM;
+	}
+	memset(ctx->iv_send, 0, ivlen);
+
+	ctx->iv_recv = sock_kmalloc(sk, ivlen, GFP_KERNEL);
+	if (!ctx->iv_recv) {
+		sock_kfree_s(sk, ctx, len);
+		return -ENOMEM;
+	}
+	memset(ctx->iv_recv, 0, ivlen);
+
+	ctx->aead_assoclen = 0;
+	ctx->recv_wanted = -1;
+	af_alg_init_completion(&ctx->completion);
+	INIT_WORK(&ctx->tx_work, tls_tx_work);
+	INIT_WORK(&ctx->rx_work, tls_rx_work);
+
+	ask->private = ctx;
+
+	aead_request_set_tfm(&ctx->aead_req, pair->tfm_send);
+	aead_request_set_tfm(&ctx->aead_resp, pair->tfm_recv);
+	aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+				  af_alg_complete, &ctx->completion);
+
+	sk->sk_destruct = tls_sock_destruct;
+
+	return 0;
+}
+
+static const struct af_alg_type algif_type_tls = {
+	.bind		=	tls_bind,
+	.release	=	tls_release,
+	.setkey		=	tls_setkey,
+	.setauthsize	=	tls_setauthsize,
+	.accept		=	tls_accept_parent,
+	.ops		=	&algif_tls_ops,
+	.name		=	"tls",
+	.owner		=	THIS_MODULE
+};
+
+static int __init algif_tls_init(void)
+{
+	int err = -ENOMEM;
+
+	tls_wq = create_singlethread_workqueue("ktlsd");
+	if (!tls_wq)
+		goto error;
+
+	err = af_alg_register_type(&algif_type_tls);
+
+	if (!err)
+		return 0;
+error:
+	if (tls_wq)
+		destroy_workqueue(tls_wq);
+	return err;
+}
+
+static void __exit algif_tls_exit(void)
+{
+	af_alg_unregister_type(&algif_type_tls);
+	destroy_workqueue(tls_wq);
+}
+
+module_init(algif_tls_init);
+module_exit(algif_tls_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Dave Watson <davejwatson@...com>");
+MODULE_DESCRIPTION("TLS kernel crypto API net interface");
--
2.4.6
--
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