tls_device.c
/* Copyright (c) 2018, 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.
*/
#include <crypto/aead.h>
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <net/dst.h>
#include <net/inet_connection_sock.h>
#include <net/tcp.h>
#include <net/tls.h>
/* device_offload_lock is used to synchronize tls_dev_add
* against NETDEV_DOWN notifications.
*/
static DECLARE_RWSEM(device_offload_lock);
static void tls_device_gc_task(struct work_struct *work);
static DECLARE_WORK(tls_device_gc_work, tls_device_gc_task);
static LIST_HEAD(tls_device_gc_list);
static LIST_HEAD(tls_device_list);
static DEFINE_SPINLOCK(tls_device_lock);
static void tls_device_free_ctx(struct tls_context *ctx)
{
struct tls_offload_context *offload_ctx = tls_offload_ctx(ctx);
kfree(offload_ctx);
kfree(ctx);
}
static void tls_device_gc_task(struct work_struct *work)
{
struct tls_context *ctx, *tmp;
unsigned long flags;
LIST_HEAD(gc_list);
spin_lock_irqsave(&tls_device_lock, flags);
list_splice_init(&tls_device_gc_list, &gc_list);
spin_unlock_irqrestore(&tls_device_lock, flags);
list_for_each_entry_safe(ctx, tmp, &gc_list, list) {
struct net_device *netdev = ctx->netdev;
if (netdev) {
netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
TLS_OFFLOAD_CTX_DIR_TX);
dev_put(netdev);
}
list_del(&ctx->list);
tls_device_free_ctx(ctx);
}
}
static void tls_device_queue_ctx_destruction(struct tls_context *ctx)
{
unsigned long flags;
spin_lock_irqsave(&tls_device_lock, flags);
list_move_tail(&ctx->list, &tls_device_gc_list);
/* schedule_work inside the spinlock
* to make sure tls_device_down waits for that work.
*/
schedule_work(&tls_device_gc_work);
spin_unlock_irqrestore(&tls_device_lock, flags);
}
/* We assume that the socket is already connected */
static struct net_device *get_netdev_for_sock(struct sock *sk)
{
struct dst_entry *dst = sk_dst_get(sk);
struct net_device *netdev = NULL;
if (likely(dst)) {
netdev = dst->dev;
dev_hold(netdev);
}
dst_release(dst);
return netdev;
}
static void destroy_record(struct tls_record_info *record)
{
int nr_frags = record->num_frags;
skb_frag_t *frag;
while (nr_frags-- > 0) {
frag = &record->frags[nr_frags];
__skb_frag_unref(frag);
}
kfree(record);
}
static void delete_all_records(struct tls_offload_context *offload_ctx)
{
struct tls_record_info *info, *temp;
list_for_each_entry_safe(info, temp, &offload_ctx->records_list, list) {
list_del(&info->list);
destroy_record(info);
}
offload_ctx->retransmit_hint = NULL;
}
static void tls_icsk_clean_acked(struct sock *sk, u32 acked_seq)
{
struct tls_context *tls_ctx = tls_get_ctx(sk);
struct tls_record_info *info, *temp;
struct tls_offload_context *ctx;
u64 deleted_records = 0;
unsigned long flags;
if (!tls_ctx)
return;
ctx = tls_offload_ctx(tls_ctx);
spin_lock_irqsave(&ctx->lock, flags);
info = ctx->retransmit_hint;
if (info && !before(acked_seq, info->end_seq)) {
ctx->retransmit_hint = NULL;
list_del(&info->list);
destroy_record(info);
deleted_records++;
}
list_for_each_entry_safe(info, temp, &ctx->records_list, list) {
if (before(acked_seq, info->end_seq))
break;
list_del(&info->list);
destroy_record(info);
deleted_records++;
}
ctx->unacked_record_sn += deleted_records;
spin_unlock_irqrestore(&ctx->lock, flags);
}
/* At this point, there should be no references on this
* socket and no in-flight SKBs associated with this
* socket, so it is safe to free all the resources.
*/
void tls_device_sk_destruct(struct sock *sk)
{
struct tls_context *tls_ctx = tls_get_ctx(sk);
struct tls_offload_context *ctx = tls_offload_ctx(tls_ctx);
if (ctx->open_record)
destroy_record(ctx->open_record);
delete_all_records(ctx);
crypto_free_aead(ctx->aead_send);
ctx->sk_destruct(sk);
clean_acked_data_disable(inet_csk(sk));
if (refcount_dec_and_test(&tls_ctx->refcount))
tls_device_queue_ctx_destruction(tls_ctx);
}
EXPORT_SYMBOL(tls_device_sk_destruct);
static void tls_append_frag(struct tls_record_info *record,
struct page_frag *pfrag,
int size)
{
skb_frag_t *frag;
frag = &record->frags[record->num_frags - 1];
if (frag->page.p == pfrag->page &&
frag->page_offset + frag->size == pfrag->offset) {
frag->size += size;
} else {
++frag;
frag->page.p = pfrag->page;
frag->page_offset = pfrag->offset;
frag->size = size;
++record->num_frags;
get_page(pfrag->page);
}
pfrag->offset += size;
record->len += size;
}
static int tls_push_record(struct sock *sk,
struct tls_context *ctx,
struct tls_offload_context *offload_ctx,
struct tls_record_info *record,
struct page_frag *pfrag,
int flags,
unsigned char record_type)
{
struct tcp_sock *tp = tcp_sk(sk);
struct page_frag dummy_tag_frag;
skb_frag_t *frag;
int i;
/* fill prepend */
frag = &record->frags[0];
tls_fill_prepend(ctx,
skb_frag_address(frag),
record->len - ctx->tx.prepend_size,
record_type);
/* HW doesn't care about the data in the tag, because it fills it. */
dummy_tag_frag.page = skb_frag_page(frag);
dummy_tag_frag.offset = 0;
tls_append_frag(record, &dummy_tag_frag, ctx->tx.tag_size);
record->end_seq = tp->write_seq + record->len;
spin_lock_irq(&offload_ctx->lock);
list_add_tail(&record->list, &offload_ctx->records_list);
spin_unlock_irq(&offload_ctx->lock);
offload_ctx->open_record = NULL;
set_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags);
tls_advance_record_sn(sk, &ctx->tx);
for (i = 0; i < record->num_frags; i++) {
frag = &record->frags[i];
sg_unmark_end(&offload_ctx->sg_tx_data[i]);
sg_set_page(&offload_ctx->sg_tx_data[i], skb_frag_page(frag),
frag->size, frag->page_offset);
sk_mem_charge(sk, frag->size);
get_page(skb_frag_page(frag));
}
sg_mark_end(&offload_ctx->sg_tx_data[record->num_frags - 1]);
/* all ready, send */
return tls_push_sg(sk, ctx, offload_ctx->sg_tx_data, 0, flags);
}
static int tls_create_new_record(struct tls_offload_context *offload_ctx,
struct page_frag *pfrag,
size_t prepend_size)
{
struct tls_record_info *record;
skb_frag_t *frag;
record = kmalloc(sizeof(*record), GFP_KERNEL);
if (!record)
return -ENOMEM;
frag = &record->frags[0];
__skb_frag_set_page(frag, pfrag->page);
frag->page_offset = pfrag->offset;
skb_frag_size_set(frag, prepend_size);
get_page(pfrag->page);
pfrag->offset += prepend_size;
record->num_frags = 1;
record->len = prepend_size;
offload_ctx->open_record = record;
return 0;
}
static int tls_do_allocation(struct sock *sk,
struct tls_offload_context *offload_ctx,
struct page_frag *pfrag,
size_t prepend_size)
{
int ret;
if (!offload_ctx->open_record) {
if (unlikely(!skb_page_frag_refill(prepend_size, pfrag,
sk->sk_allocation))) {
sk->sk_prot->enter_memory_pressure(sk);
sk_stream_moderate_sndbuf(sk);
return -ENOMEM;
}
ret = tls_create_new_record(offload_ctx, pfrag, prepend_size);
if (ret)
return ret;
if (pfrag->size > pfrag->offset)
return 0;
}
if (!sk_page_frag_refill(sk, pfrag))
return -ENOMEM;
return 0;
}
static int tls_push_data(struct sock *sk,
struct iov_iter *msg_iter,
size_t size, int flags,
unsigned char record_type)
{
struct tls_context *tls_ctx = tls_get_ctx(sk);
struct tls_offload_context *ctx = tls_offload_ctx(tls_ctx);
int tls_push_record_flags = flags | MSG_SENDPAGE_NOTLAST;
int more = flags & (MSG_SENDPAGE_NOTLAST | MSG_MORE);
struct tls_record_info *record = ctx->open_record;
struct page_frag *pfrag;
size_t orig_size = size;
u32 max_open_record_len;
int copy, rc = 0;
bool done = false;
long timeo;
if (flags &
~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_SENDPAGE_NOTLAST))
return -ENOTSUPP;
if (sk->sk_err)
return -sk->sk_err;
timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
rc = tls_complete_pending_work(sk, tls_ctx, flags, &timeo);
if (rc < 0)
return rc;
pfrag = sk_page_frag(sk);
/* TLS_HEADER_SIZE is not counted as part of the TLS record, and
* we need to leave room for an authentication tag.
*/
max_open_record_len = TLS_MAX_PAYLOAD_SIZE +
tls_ctx->tx.prepend_size;
do {
rc = tls_do_allocation(sk, ctx, pfrag,
tls_ctx->tx.prepend_size);
if (rc) {
rc = sk_stream_wait_memory(sk, &timeo);
if (!rc)
continue;
record = ctx->open_record;
if (!record)
break;
handle_error:
if (record_type != TLS_RECORD_TYPE_DATA) {
/* avoid sending partial
* record with type !=
* application_data
*/
size = orig_size;
destroy_record(record);
ctx->open_record = NULL;
} else if (record->len > tls_ctx->tx.prepend_size) {
goto last_record;
}
break;
}
record = ctx->open_record;
copy = min_t(size_t, size, (pfrag->size - pfrag->offset));
copy = min_t(size_t, copy, (max_open_record_len - record->len));
if (copy_from_iter_nocache(page_address(pfrag->page) +
pfrag->offset,
copy, msg_iter) != copy) {
rc = -EFAULT;
goto handle_error;
}
tls_append_frag(record, pfrag, copy);
size -= copy;
if (!size) {
last_record:
tls_push_record_flags = flags;
if (more) {
tls_ctx->pending_open_record_frags =
record->num_frags;
break;
}
done = true;
}
if (done || record->len >= max_open_record_len ||
(record->num_frags >= MAX_SKB_FRAGS - 1)) {
rc = tls_push_record(sk,
tls_ctx,
ctx,
record,
pfrag,
tls_push_record_flags,
record_type);
if (rc < 0)
break;
}
} while (!done);
if (orig_size - size > 0)
rc = orig_size - size;
return rc;
}
int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
{
unsigned char record_type = TLS_RECORD_TYPE_DATA;
int rc;
lock_sock(sk);
if (unlikely(msg->msg_controllen)) {
rc = tls_proccess_cmsg(sk, msg, &record_type);
if (rc)
goto out;
}
rc = tls_push_data(sk, &msg->msg_iter, size,
msg->msg_flags, record_type);
out:
release_sock(sk);
return rc;
}
int tls_device_sendpage(struct sock *sk, struct page *page,
int offset, size_t size, int flags)
{
struct iov_iter msg_iter;
char *kaddr = kmap(page);
struct kvec iov;
int rc;
if (flags & MSG_SENDPAGE_NOTLAST)
flags |= MSG_MORE;
lock_sock(sk);
if (flags & MSG_OOB) {
rc = -ENOTSUPP;
goto out;
}
iov.iov_base = kaddr + offset;
iov.iov_len = size;
iov_iter_kvec(&msg_iter, WRITE | ITER_KVEC, &iov, 1, size);
rc = tls_push_data(sk, &msg_iter, size,
flags, TLS_RECORD_TYPE_DATA);
kunmap(page);
out:
release_sock(sk);
return rc;
}
struct tls_record_info *tls_get_record(struct tls_offload_context *context,
u32 seq, u64 *p_record_sn)
{
u64 record_sn = context->hint_record_sn;
struct tls_record_info *info;
info = context->retransmit_hint;
if (!info ||
before(seq, info->end_seq - info->len)) {
/* if retransmit_hint is irrelevant start
* from the beggining of the list
*/
info = list_first_entry(&context->records_list,
struct tls_record_info, list);
record_sn = context->unacked_record_sn;
}
list_for_each_entry_from(info, &context->records_list, list) {
if (before(seq, info->end_seq)) {
if (!context->retransmit_hint ||
after(info->end_seq,
context->retransmit_hint->end_seq)) {
context->hint_record_sn = record_sn;
context->retransmit_hint = info;
}
*p_record_sn = record_sn;
return info;
}
record_sn++;
}
return NULL;
}
EXPORT_SYMBOL(tls_get_record);
static int tls_device_push_pending_record(struct sock *sk, int flags)
{
struct iov_iter msg_iter;
iov_iter_kvec(&msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
return tls_push_data(sk, &msg_iter, 0, flags, TLS_RECORD_TYPE_DATA);
}
int tls_set_device_offload(struct sock *sk, struct tls_context *ctx)
{
u16 nonce_size, tag_size, iv_size, rec_seq_size;
struct tls_record_info *start_marker_record;
struct tls_offload_context *offload_ctx;
struct tls_crypto_info *crypto_info;
struct net_device *netdev;
char *iv, *rec_seq;
struct sk_buff *skb;
int rc = -EINVAL;
__be64 rcd_sn;
if (!ctx)
goto out;
if (ctx->priv_ctx_tx) {
rc = -EEXIST;
goto out;
}
start_marker_record = kmalloc(sizeof(*start_marker_record), GFP_KERNEL);
if (!start_marker_record) {
rc = -ENOMEM;
goto out;
}
offload_ctx = kzalloc(TLS_OFFLOAD_CONTEXT_SIZE, GFP_KERNEL);
if (!offload_ctx) {
rc = -ENOMEM;
goto free_marker_record;
}
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;
break;
default:
rc = -EINVAL;
goto free_offload_ctx;
}
ctx->tx.prepend_size = TLS_HEADER_SIZE + nonce_size;
ctx->tx.tag_size = tag_size;
ctx->tx.overhead_size = ctx->tx.prepend_size + ctx->tx.tag_size;
ctx->tx.iv_size = iv_size;
ctx->tx.iv = kmalloc(iv_size + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
GFP_KERNEL);
if (!ctx->tx.iv) {
rc = -ENOMEM;
goto free_offload_ctx;
}
memcpy(ctx->tx.iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, iv, iv_size);
ctx->tx.rec_seq_size = rec_seq_size;
ctx->tx.rec_seq = kmalloc(rec_seq_size, GFP_KERNEL);
if (!ctx->tx.rec_seq) {
rc = -ENOMEM;
goto free_iv;
}
memcpy(ctx->tx.rec_seq, rec_seq, rec_seq_size);
rc = tls_sw_fallback_init(sk, offload_ctx, crypto_info);
if (rc)
goto free_rec_seq;
/* start at rec_seq - 1 to account for the start marker record */
memcpy(&rcd_sn, ctx->tx.rec_seq, sizeof(rcd_sn));
offload_ctx->unacked_record_sn = be64_to_cpu(rcd_sn) - 1;
start_marker_record->end_seq = tcp_sk(sk)->write_seq;
start_marker_record->len = 0;
start_marker_record->num_frags = 0;
INIT_LIST_HEAD(&offload_ctx->records_list);
list_add_tail(&start_marker_record->list, &offload_ctx->records_list);
spin_lock_init(&offload_ctx->lock);
sg_init_table(offload_ctx->sg_tx_data,
ARRAY_SIZE(offload_ctx->sg_tx_data));
clean_acked_data_enable(inet_csk(sk), &tls_icsk_clean_acked);
ctx->push_pending_record = tls_device_push_pending_record;
offload_ctx->sk_destruct = sk->sk_destruct;
/* TLS offload is greatly simplified if we don't send
* SKBs where only part of the payload needs to be encrypted.
* So mark the last skb in the write queue as end of record.
*/
skb = tcp_write_queue_tail(sk);
if (skb)
TCP_SKB_CB(skb)->eor = 1;
refcount_set(&ctx->refcount, 1);
/* We support starting offload on multiple sockets
* concurrently, so we only need a read lock here.
* This lock must precede get_netdev_for_sock to prevent races between
* NETDEV_DOWN and setsockopt.
*/
down_read(&device_offload_lock);
netdev = get_netdev_for_sock(sk);
if (!netdev) {
pr_err_ratelimited("%s: netdev not found\n", __func__);
rc = -EINVAL;
goto release_lock;
}
if (!(netdev->features & NETIF_F_HW_TLS_TX)) {
rc = -ENOTSUPP;
goto release_netdev;
}
/* Avoid offloading if the device is down
* We don't want to offload new flows after
* the NETDEV_DOWN event
*/
if (!(netdev->flags & IFF_UP)) {
rc = -EINVAL;
goto release_netdev;
}
ctx->priv_ctx_tx = offload_ctx;
rc = netdev->tlsdev_ops->tls_dev_add(netdev, sk, TLS_OFFLOAD_CTX_DIR_TX,
&ctx->crypto_send,
tcp_sk(sk)->write_seq);
if (rc)
goto release_netdev;
ctx->netdev = netdev;
spin_lock_irq(&tls_device_lock);
list_add_tail(&ctx->list, &tls_device_list);
spin_unlock_irq(&tls_device_lock);
sk->sk_validate_xmit_skb = tls_validate_xmit_skb;
/* following this assignment tls_is_sk_tx_device_offloaded
* will return true and the context might be accessed
* by the netdev's xmit function.
*/
smp_store_release(&sk->sk_destruct,
&tls_device_sk_destruct);
up_read(&device_offload_lock);
goto out;
release_netdev:
dev_put(netdev);
release_lock:
up_read(&device_offload_lock);
clean_acked_data_disable(inet_csk(sk));
crypto_free_aead(offload_ctx->aead_send);
free_rec_seq:
kfree(ctx->tx.rec_seq);
free_iv:
kfree(ctx->tx.iv);
free_offload_ctx:
kfree(offload_ctx);
ctx->priv_ctx_tx = NULL;
free_marker_record:
kfree(start_marker_record);
out:
return rc;
}
static int tls_device_down(struct net_device *netdev)
{
struct tls_context *ctx, *tmp;
unsigned long flags;
LIST_HEAD(list);
/* Request a write lock to block new offload attempts */
down_write(&device_offload_lock);
spin_lock_irqsave(&tls_device_lock, flags);
list_for_each_entry_safe(ctx, tmp, &tls_device_list, list) {
if (ctx->netdev != netdev ||
!refcount_inc_not_zero(&ctx->refcount))
continue;
list_move(&ctx->list, &list);
}
spin_unlock_irqrestore(&tls_device_lock, flags);
list_for_each_entry_safe(ctx, tmp, &list, list) {
netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
TLS_OFFLOAD_CTX_DIR_TX);
ctx->netdev = NULL;
dev_put(netdev);
list_del_init(&ctx->list);
if (refcount_dec_and_test(&ctx->refcount))
tls_device_free_ctx(ctx);
}
up_write(&device_offload_lock);
flush_work(&tls_device_gc_work);
return NOTIFY_DONE;
}
static int tls_dev_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
if (!(dev->features & NETIF_F_HW_TLS_TX))
return NOTIFY_DONE;
switch (event) {
case NETDEV_REGISTER:
case NETDEV_FEAT_CHANGE:
if (dev->tlsdev_ops &&
dev->tlsdev_ops->tls_dev_add &&
dev->tlsdev_ops->tls_dev_del)
return NOTIFY_DONE;
else
return NOTIFY_BAD;
case NETDEV_DOWN:
return tls_device_down(dev);
}
return NOTIFY_DONE;
}
static struct notifier_block tls_dev_notifier = {
.notifier_call = tls_dev_event,
};
void __init tls_device_init(void)
{
register_netdevice_notifier(&tls_dev_notifier);
}
void __exit tls_device_cleanup(void)
{
unregister_netdevice_notifier(&tls_dev_notifier);
flush_work(&tls_device_gc_work);
}