aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/wireguard/send.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/net/wireguard/send.c')
-rw-r--r--drivers/net/wireguard/send.c431
1 files changed, 431 insertions, 0 deletions
diff --git a/drivers/net/wireguard/send.c b/drivers/net/wireguard/send.c
new file mode 100644
index 000000000000..b0df5c717502
--- /dev/null
+++ b/drivers/net/wireguard/send.c
@@ -0,0 +1,431 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include "queueing.h"
+#include "timers.h"
+#include "device.h"
+#include "peer.h"
+#include "socket.h"
+#include "messages.h"
+#include "cookie.h"
+
+#include <linux/simd.h>
+#include <linux/uio.h>
+#include <linux/inetdevice.h>
+#include <linux/socket.h>
+#include <net/ip_tunnels.h>
+#include <net/udp.h>
+#include <net/sock.h>
+
+static void wg_packet_send_handshake_initiation(struct wg_peer *peer)
+{
+ struct message_handshake_initiation packet;
+
+ if (!wg_birthdate_has_expired(atomic64_read(&peer->last_sent_handshake),
+ REKEY_TIMEOUT))
+ return; /* This function is rate limited. */
+
+ atomic64_set(&peer->last_sent_handshake, ktime_get_boot_fast_ns());
+ net_dbg_ratelimited("%s: Sending handshake initiation to peer %llu (%pISpfsc)\n",
+ peer->device->dev->name, peer->internal_id,
+ &peer->endpoint.addr);
+
+ if (wg_noise_handshake_create_initiation(&packet, &peer->handshake)) {
+ wg_cookie_add_mac_to_packet(&packet, sizeof(packet), peer);
+ wg_timers_any_authenticated_packet_traversal(peer);
+ wg_timers_any_authenticated_packet_sent(peer);
+ atomic64_set(&peer->last_sent_handshake,
+ ktime_get_boot_fast_ns());
+ wg_socket_send_buffer_to_peer(peer, &packet, sizeof(packet),
+ HANDSHAKE_DSCP);
+ wg_timers_handshake_initiated(peer);
+ }
+}
+
+void wg_packet_handshake_send_worker(struct work_struct *work)
+{
+ struct wg_peer *peer = container_of(work, struct wg_peer,
+ transmit_handshake_work);
+
+ wg_packet_send_handshake_initiation(peer);
+ wg_peer_put(peer);
+}
+
+void wg_packet_send_queued_handshake_initiation(struct wg_peer *peer,
+ bool is_retry)
+{
+ if (!is_retry)
+ peer->timer_handshake_attempts = 0;
+
+ rcu_read_lock_bh();
+ /* We check last_sent_handshake here in addition to the actual function
+ * we're queueing up, so that we don't queue things if not strictly
+ * necessary:
+ */
+ if (!wg_birthdate_has_expired(atomic64_read(&peer->last_sent_handshake),
+ REKEY_TIMEOUT) ||
+ unlikely(READ_ONCE(peer->is_dead)))
+ goto out;
+
+ wg_peer_get(peer);
+ /* Queues up calling packet_send_queued_handshakes(peer), where we do a
+ * peer_put(peer) after:
+ */
+ if (!queue_work(peer->device->handshake_send_wq,
+ &peer->transmit_handshake_work))
+ /* If the work was already queued, we want to drop the
+ * extra reference:
+ */
+ wg_peer_put(peer);
+out:
+ rcu_read_unlock_bh();
+}
+
+void wg_packet_send_handshake_response(struct wg_peer *peer)
+{
+ struct message_handshake_response packet;
+
+ atomic64_set(&peer->last_sent_handshake, ktime_get_boot_fast_ns());
+ net_dbg_ratelimited("%s: Sending handshake response to peer %llu (%pISpfsc)\n",
+ peer->device->dev->name, peer->internal_id,
+ &peer->endpoint.addr);
+
+ if (wg_noise_handshake_create_response(&packet, &peer->handshake)) {
+ wg_cookie_add_mac_to_packet(&packet, sizeof(packet), peer);
+ if (wg_noise_handshake_begin_session(&peer->handshake,
+ &peer->keypairs)) {
+ wg_timers_session_derived(peer);
+ wg_timers_any_authenticated_packet_traversal(peer);
+ wg_timers_any_authenticated_packet_sent(peer);
+ atomic64_set(&peer->last_sent_handshake,
+ ktime_get_boot_fast_ns());
+ wg_socket_send_buffer_to_peer(peer, &packet,
+ sizeof(packet),
+ HANDSHAKE_DSCP);
+ }
+ }
+}
+
+void wg_packet_send_handshake_cookie(struct wg_device *wg,
+ struct sk_buff *initiating_skb,
+ __le32 sender_index)
+{
+ struct message_handshake_cookie packet;
+
+ net_dbg_skb_ratelimited("%s: Sending cookie response for denied handshake message for %pISpfsc\n",
+ wg->dev->name, initiating_skb);
+ wg_cookie_message_create(&packet, initiating_skb, sender_index,
+ &wg->cookie_checker);
+ wg_socket_send_buffer_as_reply_to_skb(wg, initiating_skb, &packet,
+ sizeof(packet));
+}
+
+static void keep_key_fresh(struct wg_peer *peer)
+{
+ struct noise_keypair *keypair;
+ bool send = false;
+
+ rcu_read_lock_bh();
+ keypair = rcu_dereference_bh(peer->keypairs.current_keypair);
+ if (likely(keypair && READ_ONCE(keypair->sending.is_valid)) &&
+ (unlikely(atomic64_read(&keypair->sending.counter.counter) >
+ REKEY_AFTER_MESSAGES) ||
+ (keypair->i_am_the_initiator &&
+ unlikely(wg_birthdate_has_expired(keypair->sending.birthdate,
+ REKEY_AFTER_TIME)))))
+ send = true;
+ rcu_read_unlock_bh();
+
+ if (send)
+ wg_packet_send_queued_handshake_initiation(peer, false);
+}
+
+static unsigned int calculate_skb_padding(struct sk_buff *skb)
+{
+ /* We do this modulo business with the MTU, just in case the networking
+ * layer gives us a packet that's bigger than the MTU. In that case, we
+ * wouldn't want the final subtraction to overflow in the case of the
+ * padded_size being clamped.
+ */
+ unsigned int last_unit = skb->len % PACKET_CB(skb)->mtu;
+ unsigned int padded_size = ALIGN(last_unit, MESSAGE_PADDING_MULTIPLE);
+
+ if (padded_size > PACKET_CB(skb)->mtu)
+ padded_size = PACKET_CB(skb)->mtu;
+ return padded_size - last_unit;
+}
+
+static bool encrypt_packet(struct sk_buff *skb, struct noise_keypair *keypair,
+ simd_context_t *simd_context)
+{
+ unsigned int padding_len, plaintext_len, trailer_len;
+ struct scatterlist sg[MAX_SKB_FRAGS + 8];
+ struct message_data *header;
+ struct sk_buff *trailer;
+ int num_frags;
+
+ /* Calculate lengths. */
+ padding_len = calculate_skb_padding(skb);
+ trailer_len = padding_len + noise_encrypted_len(0);
+ plaintext_len = skb->len + padding_len;
+
+ /* Expand data section to have room for padding and auth tag. */
+ num_frags = skb_cow_data(skb, trailer_len, &trailer);
+ if (unlikely(num_frags < 0 || num_frags > ARRAY_SIZE(sg)))
+ return false;
+
+ /* Set the padding to zeros, and make sure it and the auth tag are part
+ * of the skb.
+ */
+ memset(skb_tail_pointer(trailer), 0, padding_len);
+
+ /* Expand head section to have room for our header and the network
+ * stack's headers.
+ */
+ if (unlikely(skb_cow_head(skb, DATA_PACKET_HEAD_ROOM) < 0))
+ return false;
+
+ /* Finalize checksum calculation for the inner packet, if required. */
+ if (unlikely(skb->ip_summed == CHECKSUM_PARTIAL &&
+ skb_checksum_help(skb)))
+ return false;
+
+ /* Only after checksumming can we safely add on the padding at the end
+ * and the header.
+ */
+ skb_set_inner_network_header(skb, 0);
+ header = (struct message_data *)skb_push(skb, sizeof(*header));
+ header->header.type = cpu_to_le32(MESSAGE_DATA);
+ header->key_idx = keypair->remote_index;
+ header->counter = cpu_to_le64(PACKET_CB(skb)->nonce);
+ pskb_put(skb, trailer, trailer_len);
+
+ /* Now we can encrypt the scattergather segments */
+ sg_init_table(sg, num_frags);
+ if (skb_to_sgvec(skb, sg, sizeof(struct message_data),
+ noise_encrypted_len(plaintext_len)) <= 0)
+ return false;
+ return chacha20poly1305_encrypt_sg(sg, sg, plaintext_len, NULL, 0,
+ PACKET_CB(skb)->nonce,
+ keypair->sending.key, simd_context);
+}
+
+void wg_packet_send_keepalive(struct wg_peer *peer)
+{
+ struct sk_buff *skb;
+
+ if (skb_queue_empty(&peer->staged_packet_queue)) {
+ skb = alloc_skb(DATA_PACKET_HEAD_ROOM + MESSAGE_MINIMUM_LENGTH,
+ GFP_ATOMIC);
+ if (unlikely(!skb))
+ return;
+ skb_reserve(skb, DATA_PACKET_HEAD_ROOM);
+ skb->dev = peer->device->dev;
+ PACKET_CB(skb)->mtu = skb->dev->mtu;
+ skb_queue_tail(&peer->staged_packet_queue, skb);
+ net_dbg_ratelimited("%s: Sending keepalive packet to peer %llu (%pISpfsc)\n",
+ peer->device->dev->name, peer->internal_id,
+ &peer->endpoint.addr);
+ }
+
+ wg_packet_send_staged_packets(peer);
+}
+
+#define skb_walk_null_queue_safe(first, skb, next) \
+ for (skb = first, next = skb->next; skb; \
+ skb = next, next = skb ? skb->next : NULL)
+static void skb_free_null_queue(struct sk_buff *first)
+{
+ struct sk_buff *skb, *next;
+
+ skb_walk_null_queue_safe(first, skb, next)
+ dev_kfree_skb(skb);
+}
+
+static void wg_packet_create_data_done(struct sk_buff *first,
+ struct wg_peer *peer)
+{
+ struct sk_buff *skb, *next;
+ bool is_keepalive, data_sent = false;
+
+ wg_timers_any_authenticated_packet_traversal(peer);
+ wg_timers_any_authenticated_packet_sent(peer);
+ skb_walk_null_queue_safe(first, skb, next) {
+ is_keepalive = skb->len == message_data_len(0);
+ if (likely(!wg_socket_send_skb_to_peer(peer, skb,
+ PACKET_CB(skb)->ds) && !is_keepalive))
+ data_sent = true;
+ }
+
+ if (likely(data_sent))
+ wg_timers_data_sent(peer);
+
+ keep_key_fresh(peer);
+}
+
+void wg_packet_tx_worker(struct work_struct *work)
+{
+ struct crypt_queue *queue = container_of(work, struct crypt_queue,
+ work);
+ struct noise_keypair *keypair;
+ enum packet_state state;
+ struct sk_buff *first;
+ struct wg_peer *peer;
+
+ while ((first = __ptr_ring_peek(&queue->ring)) != NULL &&
+ (state = atomic_read_acquire(&PACKET_CB(first)->state)) !=
+ PACKET_STATE_UNCRYPTED) {
+ __ptr_ring_discard_one(&queue->ring);
+ peer = PACKET_PEER(first);
+ keypair = PACKET_CB(first)->keypair;
+
+ if (likely(state == PACKET_STATE_CRYPTED))
+ wg_packet_create_data_done(first, peer);
+ else
+ skb_free_null_queue(first);
+
+ wg_noise_keypair_put(keypair, false);
+ wg_peer_put(peer);
+ }
+}
+
+void wg_packet_encrypt_worker(struct work_struct *work)
+{
+ struct crypt_queue *queue = container_of(work, struct multicore_worker,
+ work)->ptr;
+ struct sk_buff *first, *skb, *next;
+ simd_context_t simd_context;
+
+ simd_get(&simd_context);
+ while ((first = ptr_ring_consume_bh(&queue->ring)) != NULL) {
+ enum packet_state state = PACKET_STATE_CRYPTED;
+
+ skb_walk_null_queue_safe(first, skb, next) {
+ if (likely(encrypt_packet(skb,
+ PACKET_CB(first)->keypair,
+ &simd_context))) {
+ wg_reset_packet(skb);
+ } else {
+ state = PACKET_STATE_DEAD;
+ break;
+ }
+ }
+ wg_queue_enqueue_per_peer(&PACKET_PEER(first)->tx_queue, first,
+ state);
+
+ simd_relax(&simd_context);
+ }
+ simd_put(&simd_context);
+}
+
+static void wg_packet_create_data(struct sk_buff *first)
+{
+ struct wg_peer *peer = PACKET_PEER(first);
+ struct wg_device *wg = peer->device;
+ int ret = -EINVAL;
+
+ rcu_read_lock_bh();
+ if (unlikely(READ_ONCE(peer->is_dead)))
+ goto err;
+
+ ret = wg_queue_enqueue_per_device_and_peer(&wg->encrypt_queue,
+ &peer->tx_queue, first,
+ wg->packet_crypt_wq,
+ &wg->encrypt_queue.last_cpu);
+ if (unlikely(ret == -EPIPE))
+ wg_queue_enqueue_per_peer(&peer->tx_queue, first,
+ PACKET_STATE_DEAD);
+err:
+ rcu_read_unlock_bh();
+ if (likely(!ret || ret == -EPIPE))
+ return;
+ wg_noise_keypair_put(PACKET_CB(first)->keypair, false);
+ wg_peer_put(peer);
+ skb_free_null_queue(first);
+}
+
+void wg_packet_purge_staged_packets(struct wg_peer *peer)
+{
+ spin_lock_bh(&peer->staged_packet_queue.lock);
+ peer->device->dev->stats.tx_dropped += peer->staged_packet_queue.qlen;
+ __skb_queue_purge(&peer->staged_packet_queue);
+ spin_unlock_bh(&peer->staged_packet_queue.lock);
+}
+
+void wg_packet_send_staged_packets(struct wg_peer *peer)
+{
+ struct noise_symmetric_key *key;
+ struct noise_keypair *keypair;
+ struct sk_buff_head packets;
+ struct sk_buff *skb;
+
+ /* Steal the current queue into our local one. */
+ __skb_queue_head_init(&packets);
+ spin_lock_bh(&peer->staged_packet_queue.lock);
+ skb_queue_splice_init(&peer->staged_packet_queue, &packets);
+ spin_unlock_bh(&peer->staged_packet_queue.lock);
+ if (unlikely(skb_queue_empty(&packets)))
+ return;
+
+ /* First we make sure we have a valid reference to a valid key. */
+ rcu_read_lock_bh();
+ keypair = wg_noise_keypair_get(
+ rcu_dereference_bh(peer->keypairs.current_keypair));
+ rcu_read_unlock_bh();
+ if (unlikely(!keypair))
+ goto out_nokey;
+ key = &keypair->sending;
+ if (unlikely(!READ_ONCE(key->is_valid)))
+ goto out_nokey;
+ if (unlikely(wg_birthdate_has_expired(key->birthdate,
+ REJECT_AFTER_TIME)))
+ goto out_invalid;
+
+ /* After we know we have a somewhat valid key, we now try to assign
+ * nonces to all of the packets in the queue. If we can't assign nonces
+ * for all of them, we just consider it a failure and wait for the next
+ * handshake.
+ */
+ skb_queue_walk(&packets, skb) {
+ /* 0 for no outer TOS: no leak. TODO: at some later point, we
+ * might consider using flowi->tos as outer instead.
+ */
+ PACKET_CB(skb)->ds = ip_tunnel_ecn_encap(0, ip_hdr(skb), skb);
+ PACKET_CB(skb)->nonce =
+ atomic64_inc_return(&key->counter.counter) - 1;
+ if (unlikely(PACKET_CB(skb)->nonce >= REJECT_AFTER_MESSAGES))
+ goto out_invalid;
+ }
+
+ packets.prev->next = NULL;
+ wg_peer_get(keypair->entry.peer);
+ PACKET_CB(packets.next)->keypair = keypair;
+ wg_packet_create_data(packets.next);
+ return;
+
+out_invalid:
+ WRITE_ONCE(key->is_valid, false);
+out_nokey:
+ wg_noise_keypair_put(keypair, false);
+
+ /* We orphan the packets if we're waiting on a handshake, so that they
+ * don't block a socket's pool.
+ */
+ skb_queue_walk(&packets, skb)
+ skb_orphan(skb);
+ /* Then we put them back on the top of the queue. We're not too
+ * concerned about accidentally getting things a little out of order if
+ * packets are being added really fast, because this queue is for before
+ * packets can even be sent and it's small anyway.
+ */
+ spin_lock_bh(&peer->staged_packet_queue.lock);
+ skb_queue_splice(&packets, &peer->staged_packet_queue);
+ spin_unlock_bh(&peer->staged_packet_queue.lock);
+
+ /* If we're exiting because there's something wrong with the key, it
+ * means we should initiate a new handshake.
+ */
+ wg_packet_send_queued_handshake_initiation(peer, false);
+}