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e8f6979981
linux/net/tls/tls_main.c
Ilya Lesokhin e8f6979981 net/tls: Add generic NIC offload infrastructure 
This patch adds a generic infrastructure to offload TLS crypto to a
network device. It enables the kernel TLS socket to skip encryption
and authentication operations on the transmit side of the data path.
Leaving those computationally expensive operations to the NIC.

The NIC offload infrastructure builds TLS records and pushes them to
the TCP layer just like the SW KTLS implementation and using the same
API.
TCP segmentation is mostly unaffected. Currently the only exception is
that we prevent mixed SKBs where only part of the payload requires
offload. In the future we are likely to add a similar restriction
following a change cipher spec record.

The notable differences between SW KTLS and NIC offloaded TLS
implementations are as follows:
1. The offloaded implementation builds "plaintext TLS record", those
records contain plaintext instead of ciphertext and place holder bytes
instead of authentication tags.
2. The offloaded implementation maintains a mapping from TCP sequence
number to TLS records. Thus given a TCP SKB sent from a NIC offloaded
TLS socket, we can use the tls NIC offload infrastructure to obtain
enough context to encrypt the payload of the SKB.
A TLS record is released when the last byte of the record is ack'ed,
this is done through the new icsk_clean_acked callback.

The infrastructure should be extendable to support various NIC offload
implementations.  However it is currently written with the
implementation below in mind:
The NIC assumes that packets from each offloaded stream are sent as
plaintext and in-order. It keeps track of the TLS records in the TCP
stream. When a packet marked for offload is transmitted, the NIC
encrypts the payload in-place and puts authentication tags in the
relevant place holders.

The responsibility for handling out-of-order packets (i.e. TCP
retransmission, qdisc drops) falls on the netdev driver.

The netdev driver keeps track of the expected TCP SN from the NIC's
perspective.  If the next packet to transmit matches the expected TCP
SN, the driver advances the expected TCP SN, and transmits the packet
with TLS offload indication.

If the next packet to transmit does not match the expected TCP SN. The
driver calls the TLS layer to obtain the TLS record that includes the
TCP of the packet for transmission. Using this TLS record, the driver
posts a work entry on the transmit queue to reconstruct the NIC TLS
state required for the offload of the out-of-order packet. It updates
the expected TCP SN accordingly and transmits the now in-order packet.
The same queue is used for packet transmission and TLS context
reconstruction to avoid the need for flushing the transmit queue before
issuing the context reconstruction request.

Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: Boris Pismenny <borisp@mellanox.com>
Signed-off-by: Aviad Yehezkel <aviadye@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01 09:42:47 -04:00

731 lines
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/*
* 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 <linux/inetdevice.h>
#include <net/tls.h>
MODULE_AUTHOR("Mellanox Technologies");
MODULE_DESCRIPTION("Transport Layer Security Support");
MODULE_LICENSE("Dual BSD/GPL");
enum {
TLSV4,
TLSV6,
TLS_NUM_PROTS,
};
enum {
TLS_BASE,
TLS_SW,
#ifdef CONFIG_TLS_DEVICE
TLS_HW,
#endif
TLS_HW_RECORD,
TLS_NUM_CONFIG,
};
static struct proto *saved_tcpv6_prot;
static DEFINE_MUTEX(tcpv6_prot_mutex);
static LIST_HEAD(device_list);
static DEFINE_MUTEX(device_mutex);
static struct proto tls_prots[TLS_NUM_PROTS][TLS_NUM_CONFIG][TLS_NUM_CONFIG];
static struct proto_ops tls_sw_proto_ops;
static void update_sk_prot(struct sock *sk, struct tls_context *ctx)
{
int ip_ver = sk->sk_family == AF_INET6 ? TLSV6 : TLSV4;
sk->sk_prot = &tls_prots[ip_ver][ctx->tx_conf][ctx->rx_conf];
}
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);
sk_proto_close = ctx->sk_proto_close;
if (ctx->tx_conf == TLS_HW_RECORD && ctx->rx_conf == TLS_HW_RECORD)
goto skip_tx_cleanup;
if (ctx->tx_conf == TLS_BASE && ctx->rx_conf == TLS_BASE) {
kfree(ctx);
ctx = NULL;
goto skip_tx_cleanup;
}
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++;
}
}
/* We need these for tls_sw_fallback handling of other packets */
if (ctx->tx_conf == TLS_SW) {
kfree(ctx->tx.rec_seq);
kfree(ctx->tx.iv);
tls_sw_free_resources_tx(sk);
}
if (ctx->rx_conf == TLS_SW) {
kfree(ctx->rx.rec_seq);
kfree(ctx->rx.iv);
tls_sw_free_resources_rx(sk);
}
#ifdef CONFIG_TLS_DEVICE
if (ctx->tx_conf != TLS_HW) {
#else
{
#endif
kfree(ctx);
ctx = NULL;
}
skip_tx_cleanup:
release_sock(sk);
sk_proto_close(sk, timeout);
/* free ctx for TLS_HW_RECORD, used by tcp_set_state
* for sk->sk_prot->unhash [tls_hw_unhash]
*/
if (ctx && ctx->tx_conf == TLS_HW_RECORD &&
ctx->rx_conf == TLS_HW_RECORD)
kfree(ctx);
}
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)) {
if (copy_to_user(optval, crypto_info, sizeof(*crypto_info)))
rc = -EFAULT;
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->tx.iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
TLS_CIPHER_AES_GCM_128_IV_SIZE);
memcpy(crypto_info_aes_gcm_128->rec_seq, ctx->tx.rec_seq,
TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE);
release_sock(sk);
if (copy_to_user(optval,
crypto_info_aes_gcm_128,
sizeof(*crypto_info_aes_gcm_128)))
rc = -EFAULT;
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_conf(struct sock *sk, char __user *optval,
unsigned int optlen, int tx)
{
struct tls_crypto_info *crypto_info;
struct tls_context *ctx = tls_get_ctx(sk);
int rc = 0;
int conf;
if (!optval || (optlen < sizeof(*crypto_info))) {
rc = -EINVAL;
goto out;
}
if (tx)
crypto_info = &ctx->crypto_send;
else
crypto_info = &ctx->crypto_recv;
/* Currently we don't support set crypto info more than one time */
if (TLS_CRYPTO_INFO_READY(crypto_info)) {
rc = -EBUSY;
goto out;
}
rc = copy_from_user(crypto_info, optval, sizeof(*crypto_info));
if (rc) {
rc = -EFAULT;
goto err_crypto_info;
}
/* check version */
if (crypto_info->version != TLS_1_2_VERSION) {
rc = -ENOTSUPP;
goto err_crypto_info;
}
switch (crypto_info->cipher_type) {
case TLS_CIPHER_AES_GCM_128: {
if (optlen != sizeof(struct tls12_crypto_info_aes_gcm_128)) {
rc = -EINVAL;
goto err_crypto_info;
}
rc = copy_from_user(crypto_info + 1, optval + sizeof(*crypto_info),
optlen - sizeof(*crypto_info));
if (rc) {
rc = -EFAULT;
goto err_crypto_info;
}
break;
}
default:
rc = -EINVAL;
goto err_crypto_info;
}
if (tx) {
#ifdef CONFIG_TLS_DEVICE
rc = tls_set_device_offload(sk, ctx);
conf = TLS_HW;
if (rc) {
#else
{
#endif
rc = tls_set_sw_offload(sk, ctx, 1);
conf = TLS_SW;
}
} else {
rc = tls_set_sw_offload(sk, ctx, 0);
conf = TLS_SW;
}
if (rc)
goto err_crypto_info;
if (tx)
ctx->tx_conf = conf;
else
ctx->rx_conf = conf;
update_sk_prot(sk, ctx);
if (tx) {
ctx->sk_write_space = sk->sk_write_space;
sk->sk_write_space = tls_write_space;
} else {
sk->sk_socket->ops = &tls_sw_proto_ops;
}
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:
case TLS_RX:
lock_sock(sk);
rc = do_tls_setsockopt_conf(sk, optval, optlen,
optname == TLS_TX);
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 struct tls_context *create_ctx(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tls_context *ctx;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return NULL;
icsk->icsk_ulp_data = ctx;
return ctx;
}
static int tls_hw_prot(struct sock *sk)
{
struct tls_context *ctx;
struct tls_device *dev;
int rc = 0;
mutex_lock(&device_mutex);
list_for_each_entry(dev, &device_list, dev_list) {
if (dev->feature && dev->feature(dev)) {
ctx = create_ctx(sk);
if (!ctx)
goto out;
ctx->hash = sk->sk_prot->hash;
ctx->unhash = sk->sk_prot->unhash;
ctx->sk_proto_close = sk->sk_prot->close;
ctx->rx_conf = TLS_HW_RECORD;
ctx->tx_conf = TLS_HW_RECORD;
update_sk_prot(sk, ctx);
rc = 1;
break;
}
}
out:
mutex_unlock(&device_mutex);
return rc;
}
static void tls_hw_unhash(struct sock *sk)
{
struct tls_context *ctx = tls_get_ctx(sk);
struct tls_device *dev;
mutex_lock(&device_mutex);
list_for_each_entry(dev, &device_list, dev_list) {
if (dev->unhash)
dev->unhash(dev, sk);
}
mutex_unlock(&device_mutex);
ctx->unhash(sk);
}
static int tls_hw_hash(struct sock *sk)
{
struct tls_context *ctx = tls_get_ctx(sk);
struct tls_device *dev;
int err;
err = ctx->hash(sk);
mutex_lock(&device_mutex);
list_for_each_entry(dev, &device_list, dev_list) {
if (dev->hash)
err |= dev->hash(dev, sk);
}
mutex_unlock(&device_mutex);
if (err)
tls_hw_unhash(sk);
return err;
}
static void build_protos(struct proto prot[TLS_NUM_CONFIG][TLS_NUM_CONFIG],
struct proto *base)
{
prot[TLS_BASE][TLS_BASE] = *base;
prot[TLS_BASE][TLS_BASE].setsockopt = tls_setsockopt;
prot[TLS_BASE][TLS_BASE].getsockopt = tls_getsockopt;
prot[TLS_BASE][TLS_BASE].close = tls_sk_proto_close;
prot[TLS_SW][TLS_BASE] = prot[TLS_BASE][TLS_BASE];
prot[TLS_SW][TLS_BASE].sendmsg = tls_sw_sendmsg;
prot[TLS_SW][TLS_BASE].sendpage = tls_sw_sendpage;
prot[TLS_BASE][TLS_SW] = prot[TLS_BASE][TLS_BASE];
prot[TLS_BASE][TLS_SW].recvmsg = tls_sw_recvmsg;
prot[TLS_BASE][TLS_SW].close = tls_sk_proto_close;
prot[TLS_SW][TLS_SW] = prot[TLS_SW][TLS_BASE];
prot[TLS_SW][TLS_SW].recvmsg = tls_sw_recvmsg;
prot[TLS_SW][TLS_SW].close = tls_sk_proto_close;
#ifdef CONFIG_TLS_DEVICE
prot[TLS_HW][TLS_BASE] = prot[TLS_BASE][TLS_BASE];
prot[TLS_HW][TLS_BASE].sendmsg = tls_device_sendmsg;
prot[TLS_HW][TLS_BASE].sendpage = tls_device_sendpage;
prot[TLS_HW][TLS_SW] = prot[TLS_BASE][TLS_SW];
prot[TLS_HW][TLS_SW].sendmsg = tls_device_sendmsg;
prot[TLS_HW][TLS_SW].sendpage = tls_device_sendpage;
#endif
prot[TLS_HW_RECORD][TLS_HW_RECORD] = *base;
prot[TLS_HW_RECORD][TLS_HW_RECORD].hash = tls_hw_hash;
prot[TLS_HW_RECORD][TLS_HW_RECORD].unhash = tls_hw_unhash;
prot[TLS_HW_RECORD][TLS_HW_RECORD].close = tls_sk_proto_close;
}
static int tls_init(struct sock *sk)
{
int ip_ver = sk->sk_family == AF_INET6 ? TLSV6 : TLSV4;
struct tls_context *ctx;
int rc = 0;
if (tls_hw_prot(sk))
goto out;
/* The TLS ulp is currently supported only for TCP sockets
* in ESTABLISHED state.
* Supporting sockets in LISTEN state will require us
* to modify the accept implementation to clone rather then
* share the ulp context.
*/
if (sk->sk_state != TCP_ESTABLISHED)
return -ENOTSUPP;
/* allocate tls context */
ctx = create_ctx(sk);
if (!ctx) {
rc = -ENOMEM;
goto out;
}
ctx->setsockopt = sk->sk_prot->setsockopt;
ctx->getsockopt = sk->sk_prot->getsockopt;
ctx->sk_proto_close = sk->sk_prot->close;
/* Build IPv6 TLS whenever the address of tcpv6 _prot changes */
if (ip_ver == TLSV6 &&
unlikely(sk->sk_prot != smp_load_acquire(&saved_tcpv6_prot))) {
mutex_lock(&tcpv6_prot_mutex);
if (likely(sk->sk_prot != saved_tcpv6_prot)) {
build_protos(tls_prots[TLSV6], sk->sk_prot);
smp_store_release(&saved_tcpv6_prot, sk->sk_prot);
}
mutex_unlock(&tcpv6_prot_mutex);
}
ctx->tx_conf = TLS_BASE;
ctx->rx_conf = TLS_BASE;
update_sk_prot(sk, ctx);
out:
return rc;
}
void tls_register_device(struct tls_device *device)
{
mutex_lock(&device_mutex);
list_add_tail(&device->dev_list, &device_list);
mutex_unlock(&device_mutex);
}
EXPORT_SYMBOL(tls_register_device);
void tls_unregister_device(struct tls_device *device)
{
mutex_lock(&device_mutex);
list_del(&device->dev_list);
mutex_unlock(&device_mutex);
}
EXPORT_SYMBOL(tls_unregister_device);
static struct tcp_ulp_ops tcp_tls_ulp_ops __read_mostly = {
.name = "tls",
.uid = TCP_ULP_TLS,
.user_visible = true,
.owner = THIS_MODULE,
.init = tls_init,
};
static int __init tls_register(void)
{
build_protos(tls_prots[TLSV4], &tcp_prot);
tls_sw_proto_ops = inet_stream_ops;
tls_sw_proto_ops.poll = tls_sw_poll;
tls_sw_proto_ops.splice_read = tls_sw_splice_read;
#ifdef CONFIG_TLS_DEVICE
tls_device_init();
#endif
tcp_register_ulp(&tcp_tls_ulp_ops);
return 0;
}
static void __exit tls_unregister(void)
{
tcp_unregister_ulp(&tcp_tls_ulp_ops);
#ifdef CONFIG_TLS_DEVICE
tls_device_cleanup();
#endif
}
module_init(tls_register);
module_exit(tls_unregister);
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