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>

MAINTAINERS

@@ -8978,6 +8978,16 @@ F:	net/ipv6/
 F:	include/net/ip*
 F:	arch/x86/net/*
 
+NETWORKING [TLS]
+M:	Ilya Lesokhin <ilyal@mellanox.com>
+M:	Aviad Yehezkel <aviadye@mellanox.com>
+M:	Dave Watson <davejwatson@fb.com>
+L:	netdev@vger.kernel.org
+S:	Maintained
+F:	net/tls/*
+F:	include/uapi/linux/tls.h
+F:	include/net/tls.h
+
 NETWORKING [IPSEC]
 M:	Steffen Klassert <steffen.klassert@secunet.com>
 M:	Herbert Xu <herbert@gondor.apana.org.au>

include/linux/socket.h

@@ -334,6 +334,7 @@ struct ucred {
 #define SOL_ALG		279
 #define SOL_NFC		280
 #define SOL_KCM		281
+#define SOL_TLS		282
 
 /* IPX options */
 #define IPX_TYPE	1

include/net/tls.h

@@ -0,0 +1,237 @@
+/*
+ * 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.
+ */
+
+#ifndef _TLS_OFFLOAD_H
+#define _TLS_OFFLOAD_H
+
+#include <linux/types.h>
+
+#include <uapi/linux/tls.h>
+
+
+/* Maximum data size carried in a TLS record */
+#define TLS_MAX_PAYLOAD_SIZE		((size_t)1 << 14)
+
+#define TLS_HEADER_SIZE			5
+#define TLS_NONCE_OFFSET		TLS_HEADER_SIZE
+
+#define TLS_CRYPTO_INFO_READY(info)	((info)->cipher_type)
+
+#define TLS_RECORD_TYPE_DATA		0x17
+
+#define TLS_AAD_SPACE_SIZE		13
+
+struct tls_sw_context {
+	struct crypto_aead *aead_send;
+
+	/* Sending context */
+	char aad_space[TLS_AAD_SPACE_SIZE];
+
+	unsigned int sg_plaintext_size;
+	int sg_plaintext_num_elem;
+	struct scatterlist sg_plaintext_data[MAX_SKB_FRAGS];
+
+	unsigned int sg_encrypted_size;
+	int sg_encrypted_num_elem;
+	struct scatterlist sg_encrypted_data[MAX_SKB_FRAGS];
+
+	/* AAD | sg_plaintext_data | sg_tag */
+	struct scatterlist sg_aead_in[2];
+	/* AAD | sg_encrypted_data (data contain overhead for hdr&iv&tag) */
+	struct scatterlist sg_aead_out[2];
+};
+
+enum {
+	TLS_PENDING_CLOSED_RECORD
+};
+
+struct tls_context {
+	union {
+		struct tls_crypto_info crypto_send;
+		struct tls12_crypto_info_aes_gcm_128 crypto_send_aes_gcm_128;
+	};
+
+	void *priv_ctx;
+
+	u16 prepend_size;
+	u16 tag_size;
+	u16 overhead_size;
+	u16 iv_size;
+	char *iv;
+	u16 rec_seq_size;
+	char *rec_seq;
+
+	struct scatterlist *partially_sent_record;
+	u16 partially_sent_offset;
+	unsigned long flags;
+
+	u16 pending_open_record_frags;
+	int (*push_pending_record)(struct sock *sk, int flags);
+	void (*free_resources)(struct sock *sk);
+
+	void (*sk_write_space)(struct sock *sk);
+	void (*sk_proto_close)(struct sock *sk, long timeout);
+
+	int  (*setsockopt)(struct sock *sk, int level,
+			   int optname, char __user *optval,
+			   unsigned int optlen);
+	int  (*getsockopt)(struct sock *sk, int level,
+			   int optname, char __user *optval,
+			   int __user *optlen);
+};
+
+int wait_on_pending_writer(struct sock *sk, long *timeo);
+int tls_sk_query(struct sock *sk, int optname, char __user *optval,
+		int __user *optlen);
+int tls_sk_attach(struct sock *sk, int optname, char __user *optval,
+		  unsigned int optlen);
+
+
+int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx);
+int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
+int tls_sw_sendpage(struct sock *sk, struct page *page,
+		    int offset, size_t size, int flags);
+void tls_sw_close(struct sock *sk, long timeout);
+
+void tls_sk_destruct(struct sock *sk, struct tls_context *ctx);
+void tls_icsk_clean_acked(struct sock *sk);
+
+int tls_push_sg(struct sock *sk, struct tls_context *ctx,
+		struct scatterlist *sg, u16 first_offset,
+		int flags);
+int tls_push_pending_closed_record(struct sock *sk, struct tls_context *ctx,
+				   int flags, long *timeo);
+
+static inline bool tls_is_pending_closed_record(struct tls_context *ctx)
+{
+	return test_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags);
+}
+
+static inline int tls_complete_pending_work(struct sock *sk,
+					    struct tls_context *ctx,
+					    int flags, long *timeo)
+{
+	int rc = 0;
+
+	if (unlikely(sk->sk_write_pending))
+		rc = wait_on_pending_writer(sk, timeo);
+
+	if (!rc && tls_is_pending_closed_record(ctx))
+		rc = tls_push_pending_closed_record(sk, ctx, flags, timeo);
+
+	return rc;
+}
+
+static inline bool tls_is_partially_sent_record(struct tls_context *ctx)
+{
+	return !!ctx->partially_sent_record;
+}
+
+static inline bool tls_is_pending_open_record(struct tls_context *tls_ctx)
+{
+	return tls_ctx->pending_open_record_frags;
+}
+
+static inline void tls_err_abort(struct sock *sk)
+{
+	sk->sk_err = -EBADMSG;
+	sk->sk_error_report(sk);
+}
+
+static inline bool tls_bigint_increment(unsigned char *seq, int len)
+{
+	int i;
+
+	for (i = len - 1; i >= 0; i--) {
+		++seq[i];
+		if (seq[i] != 0)
+			break;
+	}
+
+	return (i == -1);
+}
+
+static inline void tls_advance_record_sn(struct sock *sk,
+					 struct tls_context *ctx)
+{
+	if (tls_bigint_increment(ctx->rec_seq, ctx->rec_seq_size))
+		tls_err_abort(sk);
+	tls_bigint_increment(ctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
+			     ctx->iv_size);
+}
+
+static inline void tls_fill_prepend(struct tls_context *ctx,
+			     char *buf,
+			     size_t plaintext_len,
+			     unsigned char record_type)
+{
+	size_t pkt_len, iv_size = ctx->iv_size;
+
+	pkt_len = plaintext_len + iv_size + ctx->tag_size;
+
+	/* we cover nonce explicit here as well, so buf should be of
+	 * size KTLS_DTLS_HEADER_SIZE + KTLS_DTLS_NONCE_EXPLICIT_SIZE
+	 */
+	buf[0] = record_type;
+	buf[1] = TLS_VERSION_MINOR(ctx->crypto_send.version);
+	buf[2] = TLS_VERSION_MAJOR(ctx->crypto_send.version);
+	/* we can use IV for nonce explicit according to spec */
+	buf[3] = pkt_len >> 8;
+	buf[4] = pkt_len & 0xFF;
+	memcpy(buf + TLS_NONCE_OFFSET,
+	       ctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, iv_size);
+}
+
+static inline struct tls_context *tls_get_ctx(const struct sock *sk)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	return icsk->icsk_ulp_data;
+}
+
+static inline struct tls_sw_context *tls_sw_ctx(
+		const struct tls_context *tls_ctx)
+{
+	return (struct tls_sw_context *)tls_ctx->priv_ctx;
+}
+
+static inline struct tls_offload_context *tls_offload_ctx(
+		const struct tls_context *tls_ctx)
+{
+	return (struct tls_offload_context *)tls_ctx->priv_ctx;
+}
+
+int tls_proccess_cmsg(struct sock *sk, struct msghdr *msg,
+		      unsigned char *record_type);
+
+#endif /* _TLS_OFFLOAD_H */

include/uapi/linux/tls.h

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2016-2017, Mellanox Technologies. 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.
+ */
+
+#ifndef _UAPI_LINUX_TLS_H
+#define _UAPI_LINUX_TLS_H
+
+#include <linux/types.h>
+#include <asm/byteorder.h>
+#include <linux/socket.h>
+#include <linux/tcp.h>
+#include <net/tcp.h>
+
+/* TLS socket options */
+#define TLS_TX			1	/* Set transmit parameters */
+
+/* Supported versions */
+#define TLS_VERSION_MINOR(ver)	((ver) & 0xFF)
+#define TLS_VERSION_MAJOR(ver)	(((ver) >> 8) & 0xFF)
+
+#define TLS_VERSION_NUMBER(id)	((((id##_VERSION_MAJOR) & 0xFF) << 8) |	\
+				 ((id##_VERSION_MINOR) & 0xFF))
+
+#define TLS_1_2_VERSION_MAJOR	0x3
+#define TLS_1_2_VERSION_MINOR	0x3
+#define TLS_1_2_VERSION		TLS_VERSION_NUMBER(TLS_1_2)
+
+/* Supported ciphers */
+#define TLS_CIPHER_AES_GCM_128				51
+#define TLS_CIPHER_AES_GCM_128_IV_SIZE			8
+#define TLS_CIPHER_AES_GCM_128_KEY_SIZE		16
+#define TLS_CIPHER_AES_GCM_128_SALT_SIZE		4
+#define TLS_CIPHER_AES_GCM_128_TAG_SIZE		16
+#define TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE		8
+
+#define TLS_SET_RECORD_TYPE	1
+
+struct tls_crypto_info {
+	__u16 version;
+	__u16 cipher_type;
+};
+
+struct tls12_crypto_info_aes_gcm_128 {
+	struct tls_crypto_info info;
+	unsigned char iv[TLS_CIPHER_AES_GCM_128_IV_SIZE];
+	unsigned char key[TLS_CIPHER_AES_GCM_128_KEY_SIZE];
+	unsigned char salt[TLS_CIPHER_AES_GCM_128_SALT_SIZE];
+	unsigned char rec_seq[TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE];
+};
+
+#endif /* _UAPI_LINUX_TLS_H */

net/Kconfig

@@ -55,6 +55,7 @@ menu "Networking options"
 
 source "net/packet/Kconfig"
 source "net/unix/Kconfig"
+source "net/tls/Kconfig"
 source "net/xfrm/Kconfig"
 source "net/iucv/Kconfig"
 source "net/smc/Kconfig"

net/Makefile

@@ -15,6 +15,7 @@ obj-$(CONFIG_LLC)		+= llc/
 obj-$(CONFIG_NET)		+= ethernet/ 802/ sched/ netlink/ bpf/
 obj-$(CONFIG_NETFILTER)		+= netfilter/
 obj-$(CONFIG_INET)		+= ipv4/
+obj-$(CONFIG_TLS)		+= tls/
 obj-$(CONFIG_XFRM)		+= xfrm/
 obj-$(CONFIG_UNIX)		+= unix/
 obj-$(CONFIG_NET)		+= ipv6/

net/tls/Kconfig

@@ -0,0 +1,12 @@
+#
+# TLS configuration
+#
+config TLS
+	tristate "Transport Layer Security support"
+	depends on NET
+	default m
+	---help---
+	Enable kernel support for TLS protocol. This allows symmetric
+	encryption handling of the TLS protocol to be done in-kernel.
+
+	If unsure, say M.

net/tls/Makefile

@@ -0,0 +1,7 @@
+#
+# Makefile for the TLS subsystem.
+#
+
+obj-$(CONFIG_TLS) += tls.o
+
+tls-y := tls_main.o tls_sw.o