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, 487 insertions, 0 deletions

diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
new file mode 100644
index 0000000..2ebc328
--- /dev/null
+++ b/net/tls/tls_main.c
@@ -0,0 +1,487 @@
+/*
+ * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. 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 <net/tcp.h>
+#include <net/inet_common.h>
+#include <linux/highmem.h>
+#include <linux/netdevice.h>
+#include <linux/sched/signal.h>
+
+#include <net/tls.h>
+
+MODULE_AUTHOR("Mellanox Technologies");
+MODULE_DESCRIPTION("Transport Layer Security Support");
+MODULE_LICENSE("Dual BSD/GPL");
+
+static struct proto tls_base_prot;
+static struct proto tls_sw_prot;
+
+int wait_on_pending_writer(struct sock *sk, long *timeo)
+{
+	int rc = 0;
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+
+	add_wait_queue(sk_sleep(sk), &wait);
+	while (1) {
+		if (!*timeo) {
+			rc = -EAGAIN;
+			break;
+		}
+
+		if (signal_pending(current)) {
+			rc = sock_intr_errno(*timeo);
+			break;
+		}
+
+		if (sk_wait_event(sk, timeo, !sk->sk_write_pending, &wait))
+			break;
+	}
+	remove_wait_queue(sk_sleep(sk), &wait);
+	return rc;
+}
+
+int tls_push_sg(struct sock *sk,
+		struct tls_context *ctx,
+		struct scatterlist *sg,
+		u16 first_offset,
+		int flags)
+{
+	int sendpage_flags = flags | MSG_SENDPAGE_NOTLAST;
+	int ret = 0;
+	struct page *p;
+	size_t size;
+	int offset = first_offset;
+
+	size = sg->length - offset;
+	offset += sg->offset;
+
+	while (1) {
+		if (sg_is_last(sg))
+			sendpage_flags = flags;
+
+		/* is sending application-limited? */
+		tcp_rate_check_app_limited(sk);
+		p = sg_page(sg);
+retry:
+		ret = do_tcp_sendpages(sk, p, offset, size, sendpage_flags);
+
+		if (ret != size) {
+			if (ret > 0) {
+				offset += ret;
+				size -= ret;
+				goto retry;
+			}
+
+			offset -= sg->offset;
+			ctx->partially_sent_offset = offset;
+			ctx->partially_sent_record = (void *)sg;
+			return ret;
+		}
+
+		put_page(p);
+		sk_mem_uncharge(sk, sg->length);
+		sg = sg_next(sg);
+		if (!sg)
+			break;
+
+		offset = sg->offset;
+		size = sg->length;
+	}
+
+	clear_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags);
+
+	return 0;
+}
+
+static int tls_handle_open_record(struct sock *sk, int flags)
+{
+	struct tls_context *ctx = tls_get_ctx(sk);
+
+	if (tls_is_pending_open_record(ctx))
+		return ctx->push_pending_record(sk, flags);
+
+	return 0;
+}
+
+int tls_proccess_cmsg(struct sock *sk, struct msghdr *msg,
+		      unsigned char *record_type)
+{
+	struct cmsghdr *cmsg;
+	int rc = -EINVAL;
+
+	for_each_cmsghdr(cmsg, msg) {
+		if (!CMSG_OK(msg, cmsg))
+			return -EINVAL;
+		if (cmsg->cmsg_level != SOL_TLS)
+			continue;
+
+		switch (cmsg->cmsg_type) {
+		case TLS_SET_RECORD_TYPE:
+			if (cmsg->cmsg_len < CMSG_LEN(sizeof(*record_type)))
+				return -EINVAL;
+
+			if (msg->msg_flags & MSG_MORE)
+				return -EINVAL;
+
+			rc = tls_handle_open_record(sk, msg->msg_flags);
+			if (rc)
+				return rc;
+
+			*record_type = *(unsigned char *)CMSG_DATA(cmsg);
+			rc = 0;
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return rc;
+}
+
+int tls_push_pending_closed_record(struct sock *sk, struct tls_context *ctx,
+				   int flags, long *timeo)
+{
+	struct scatterlist *sg;
+	u16 offset;
+
+	if (!tls_is_partially_sent_record(ctx))
+		return ctx->push_pending_record(sk, flags);
+
+	sg = ctx->partially_sent_record;
+	offset = ctx->partially_sent_offset;
+
+	ctx->partially_sent_record = NULL;
+	return tls_push_sg(sk, ctx, sg, offset, flags);
+}
+
+static void tls_write_space(struct sock *sk)
+{
+	struct tls_context *ctx = tls_get_ctx(sk);
+
+	if (!sk->sk_write_pending && tls_is_pending_closed_record(ctx)) {
+		gfp_t sk_allocation = sk->sk_allocation;
+		int rc;
+		long timeo = 0;
+
+		sk->sk_allocation = GFP_ATOMIC;
+		rc = tls_push_pending_closed_record(sk, ctx,
+						    MSG_DONTWAIT |
+						    MSG_NOSIGNAL,
+						    &timeo);
+		sk->sk_allocation = sk_allocation;
+
+		if (rc < 0)
+			return;
+	}
+
+	ctx->sk_write_space(sk);
+}
+
+static void tls_sk_proto_close(struct sock *sk, long timeout)
+{
+	struct tls_context *ctx = tls_get_ctx(sk);
+	long timeo = sock_sndtimeo(sk, 0);
+	void (*sk_proto_close)(struct sock *sk, long timeout);
+
+	lock_sock(sk);
+
+	if (!tls_complete_pending_work(sk, ctx, 0, &timeo))
+		tls_handle_open_record(sk, 0);
+
+	if (ctx->partially_sent_record) {
+		struct scatterlist *sg = ctx->partially_sent_record;
+
+		while (1) {
+			put_page(sg_page(sg));
+			sk_mem_uncharge(sk, sg->length);
+
+			if (sg_is_last(sg))
+				break;
+			sg++;
+		}
+	}
+	ctx->free_resources(sk);
+	kfree(ctx->rec_seq);
+	kfree(ctx->iv);
+
+	sk_proto_close = ctx->sk_proto_close;
+	kfree(ctx);
+
+	release_sock(sk);
+	sk_proto_close(sk, timeout);
+}
+
+static int do_tls_getsockopt_tx(struct sock *sk, char __user *optval,
+				int __user *optlen)
+{
+	int rc = 0;
+	struct tls_context *ctx = tls_get_ctx(sk);
+	struct tls_crypto_info *crypto_info;
+	int len;
+
+	if (get_user(len, optlen))
+		return -EFAULT;
+
+	if (!optval || (len < sizeof(*crypto_info))) {
+		rc = -EINVAL;
+		goto out;
+	}
+
+	if (!ctx) {
+		rc = -EBUSY;
+		goto out;
+	}
+
+	/* get user crypto info */
+	crypto_info = &ctx->crypto_send;
+
+	if (!TLS_CRYPTO_INFO_READY(crypto_info)) {
+		rc = -EBUSY;
+		goto out;
+	}
+
+	if (len == sizeof(crypto_info)) {
+		rc = copy_to_user(optval, crypto_info, sizeof(*crypto_info));
+		goto out;
+	}
+
+	switch (crypto_info->cipher_type) {
+	case TLS_CIPHER_AES_GCM_128: {
+		struct tls12_crypto_info_aes_gcm_128 *
+		  crypto_info_aes_gcm_128 =
+		  container_of(crypto_info,
+			       struct tls12_crypto_info_aes_gcm_128,
+			       info);
+
+		if (len != sizeof(*crypto_info_aes_gcm_128)) {
+			rc = -EINVAL;
+			goto out;
+		}
+		lock_sock(sk);
+		memcpy(crypto_info_aes_gcm_128->iv, ctx->iv,
+		       TLS_CIPHER_AES_GCM_128_IV_SIZE);
+		release_sock(sk);
+		rc = copy_to_user(optval,
+				  crypto_info_aes_gcm_128,
+				  sizeof(*crypto_info_aes_gcm_128));
+		break;
+	}
+	default:
+		rc = -EINVAL;
+	}
+
+out:
+	return rc;
+}
+
+static int do_tls_getsockopt(struct sock *sk, int optname,
+			     char __user *optval, int __user *optlen)
+{
+	int rc = 0;
+
+	switch (optname) {
+	case TLS_TX:
+		rc = do_tls_getsockopt_tx(sk, optval, optlen);
+		break;
+	default:
+		rc = -ENOPROTOOPT;
+		break;
+	}
+	return rc;
+}
+
+static int tls_getsockopt(struct sock *sk, int level, int optname,
+			  char __user *optval, int __user *optlen)
+{
+	struct tls_context *ctx = tls_get_ctx(sk);
+
+	if (level != SOL_TLS)
+		return ctx->getsockopt(sk, level, optname, optval, optlen);
+
+	return do_tls_getsockopt(sk, optname, optval, optlen);
+}
+
+static int do_tls_setsockopt_tx(struct sock *sk, char __user *optval,
+				unsigned int optlen)
+{
+	struct tls_crypto_info *crypto_info, tmp_crypto_info;
+	struct tls_context *ctx = tls_get_ctx(sk);
+	struct proto *prot = NULL;
+	int rc = 0;
+
+	if (!optval || (optlen < sizeof(*crypto_info))) {
+		rc = -EINVAL;
+		goto out;
+	}
+
+	rc = copy_from_user(&tmp_crypto_info, optval, sizeof(*crypto_info));
+	if (rc) {
+		rc = -EFAULT;
+		goto out;
+	}
+
+	/* check version */
+	if (tmp_crypto_info.version != TLS_1_2_VERSION) {
+		rc = -ENOTSUPP;
+		goto out;
+	}
+
+	/* get user crypto info */
+	crypto_info = &ctx->crypto_send;
+
+	/* Currently we don't support set crypto info more than one time */
+	if (TLS_CRYPTO_INFO_READY(crypto_info))
+		goto out;
+
+	switch (tmp_crypto_info.cipher_type) {
+	case TLS_CIPHER_AES_GCM_128: {
+		if (optlen != sizeof(struct tls12_crypto_info_aes_gcm_128)) {
+			rc = -EINVAL;
+			goto out;
+		}
+		rc = copy_from_user(
+		  crypto_info,
+		  optval,
+		  sizeof(struct tls12_crypto_info_aes_gcm_128));
+
+		if (rc) {
+			rc = -EFAULT;
+			goto err_crypto_info;
+		}
+		break;
+	}
+	default:
+		rc = -EINVAL;
+		goto out;
+	}
+
+	ctx->sk_write_space = sk->sk_write_space;
+	sk->sk_write_space = tls_write_space;
+
+	ctx->sk_proto_close = sk->sk_prot->close;
+
+	/* currently SW is default, we will have ethtool in future */
+	rc = tls_set_sw_offload(sk, ctx);
+	prot = &tls_sw_prot;
+	if (rc)
+		goto err_crypto_info;
+
+	sk->sk_prot = prot;
+	goto out;
+
+err_crypto_info:
+	memset(crypto_info, 0, sizeof(*crypto_info));
+out:
+	return rc;
+}
+
+static int do_tls_setsockopt(struct sock *sk, int optname,
+			     char __user *optval, unsigned int optlen)
+{
+	int rc = 0;
+
+	switch (optname) {
+	case TLS_TX:
+		lock_sock(sk);
+		rc = do_tls_setsockopt_tx(sk, optval, optlen);
+		release_sock(sk);
+		break;
+	default:
+		rc = -ENOPROTOOPT;
+		break;
+	}
+	return rc;
+}
+
+static int tls_setsockopt(struct sock *sk, int level, int optname,
+			  char __user *optval, unsigned int optlen)
+{
+	struct tls_context *ctx = tls_get_ctx(sk);
+
+	if (level != SOL_TLS)
+		return ctx->setsockopt(sk, level, optname, optval, optlen);
+
+	return do_tls_setsockopt(sk, optname, optval, optlen);
+}
+
+static int tls_init(struct sock *sk)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+	struct tls_context *ctx;
+	int rc = 0;
+
+	/* allocate tls context */
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	icsk->icsk_ulp_data = ctx;
+	ctx->setsockopt = sk->sk_prot->setsockopt;
+	ctx->getsockopt = sk->sk_prot->getsockopt;
+	sk->sk_prot = &tls_base_prot;
+out:
+	return rc;
+}
+
+static struct tcp_ulp_ops tcp_tls_ulp_ops __read_mostly = {
+	.name			= "tls",
+	.owner			= THIS_MODULE,
+	.init			= tls_init,
+};
+
+static int __init tls_register(void)
+{
+	tls_base_prot			= tcp_prot;
+	tls_base_prot.setsockopt	= tls_setsockopt;
+	tls_base_prot.getsockopt	= tls_getsockopt;
+
+	tls_sw_prot			= tls_base_prot;
+	tls_sw_prot.sendmsg		= tls_sw_sendmsg;
+	tls_sw_prot.sendpage            = tls_sw_sendpage;
+	tls_sw_prot.close               = tls_sk_proto_close;
+
+	tcp_register_ulp(&tcp_tls_ulp_ops);
+
+	return 0;
+}
+
+static void __exit tls_unregister(void)
+{
+	tcp_unregister_ulp(&tcp_tls_ulp_ops);
+}
+
+module_init(tls_register);
+module_exit(tls_unregister);