mirror of https://gitee.com/openkylin/linux.git
829 lines
26 KiB
C
829 lines
26 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*/
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#include "noise.h"
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#include "device.h"
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#include "peer.h"
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#include "messages.h"
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#include "queueing.h"
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#include "peerlookup.h"
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#include <linux/rcupdate.h>
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#include <linux/slab.h>
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#include <linux/bitmap.h>
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#include <linux/scatterlist.h>
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#include <linux/highmem.h>
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#include <crypto/algapi.h>
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/* This implements Noise_IKpsk2:
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*
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* <- s
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* ******
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* -> e, es, s, ss, {t}
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* <- e, ee, se, psk, {}
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*/
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static const u8 handshake_name[37] = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s";
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static const u8 identifier_name[34] = "WireGuard v1 zx2c4 Jason@zx2c4.com";
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static u8 handshake_init_hash[NOISE_HASH_LEN] __ro_after_init;
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static u8 handshake_init_chaining_key[NOISE_HASH_LEN] __ro_after_init;
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static atomic64_t keypair_counter = ATOMIC64_INIT(0);
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void __init wg_noise_init(void)
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{
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struct blake2s_state blake;
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blake2s(handshake_init_chaining_key, handshake_name, NULL,
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NOISE_HASH_LEN, sizeof(handshake_name), 0);
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blake2s_init(&blake, NOISE_HASH_LEN);
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blake2s_update(&blake, handshake_init_chaining_key, NOISE_HASH_LEN);
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blake2s_update(&blake, identifier_name, sizeof(identifier_name));
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blake2s_final(&blake, handshake_init_hash);
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}
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/* Must hold peer->handshake.static_identity->lock */
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void wg_noise_precompute_static_static(struct wg_peer *peer)
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{
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down_write(&peer->handshake.lock);
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if (!peer->handshake.static_identity->has_identity ||
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!curve25519(peer->handshake.precomputed_static_static,
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peer->handshake.static_identity->static_private,
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peer->handshake.remote_static))
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memset(peer->handshake.precomputed_static_static, 0,
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NOISE_PUBLIC_KEY_LEN);
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up_write(&peer->handshake.lock);
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}
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void wg_noise_handshake_init(struct noise_handshake *handshake,
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struct noise_static_identity *static_identity,
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const u8 peer_public_key[NOISE_PUBLIC_KEY_LEN],
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const u8 peer_preshared_key[NOISE_SYMMETRIC_KEY_LEN],
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struct wg_peer *peer)
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{
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memset(handshake, 0, sizeof(*handshake));
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init_rwsem(&handshake->lock);
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handshake->entry.type = INDEX_HASHTABLE_HANDSHAKE;
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handshake->entry.peer = peer;
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memcpy(handshake->remote_static, peer_public_key, NOISE_PUBLIC_KEY_LEN);
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if (peer_preshared_key)
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memcpy(handshake->preshared_key, peer_preshared_key,
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NOISE_SYMMETRIC_KEY_LEN);
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handshake->static_identity = static_identity;
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handshake->state = HANDSHAKE_ZEROED;
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wg_noise_precompute_static_static(peer);
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}
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static void handshake_zero(struct noise_handshake *handshake)
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{
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memset(&handshake->ephemeral_private, 0, NOISE_PUBLIC_KEY_LEN);
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memset(&handshake->remote_ephemeral, 0, NOISE_PUBLIC_KEY_LEN);
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memset(&handshake->hash, 0, NOISE_HASH_LEN);
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memset(&handshake->chaining_key, 0, NOISE_HASH_LEN);
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handshake->remote_index = 0;
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handshake->state = HANDSHAKE_ZEROED;
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}
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void wg_noise_handshake_clear(struct noise_handshake *handshake)
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{
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down_write(&handshake->lock);
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wg_index_hashtable_remove(
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handshake->entry.peer->device->index_hashtable,
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&handshake->entry);
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handshake_zero(handshake);
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up_write(&handshake->lock);
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}
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static struct noise_keypair *keypair_create(struct wg_peer *peer)
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{
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struct noise_keypair *keypair = kzalloc(sizeof(*keypair), GFP_KERNEL);
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if (unlikely(!keypair))
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return NULL;
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spin_lock_init(&keypair->receiving_counter.lock);
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keypair->internal_id = atomic64_inc_return(&keypair_counter);
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keypair->entry.type = INDEX_HASHTABLE_KEYPAIR;
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keypair->entry.peer = peer;
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kref_init(&keypair->refcount);
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return keypair;
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}
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static void keypair_free_rcu(struct rcu_head *rcu)
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{
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kfree_sensitive(container_of(rcu, struct noise_keypair, rcu));
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}
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static void keypair_free_kref(struct kref *kref)
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{
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struct noise_keypair *keypair =
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container_of(kref, struct noise_keypair, refcount);
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net_dbg_ratelimited("%s: Keypair %llu destroyed for peer %llu\n",
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keypair->entry.peer->device->dev->name,
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keypair->internal_id,
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keypair->entry.peer->internal_id);
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wg_index_hashtable_remove(keypair->entry.peer->device->index_hashtable,
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&keypair->entry);
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call_rcu(&keypair->rcu, keypair_free_rcu);
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}
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void wg_noise_keypair_put(struct noise_keypair *keypair, bool unreference_now)
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{
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if (unlikely(!keypair))
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return;
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if (unlikely(unreference_now))
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wg_index_hashtable_remove(
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keypair->entry.peer->device->index_hashtable,
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&keypair->entry);
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kref_put(&keypair->refcount, keypair_free_kref);
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}
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struct noise_keypair *wg_noise_keypair_get(struct noise_keypair *keypair)
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{
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RCU_LOCKDEP_WARN(!rcu_read_lock_bh_held(),
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"Taking noise keypair reference without holding the RCU BH read lock");
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if (unlikely(!keypair || !kref_get_unless_zero(&keypair->refcount)))
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return NULL;
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return keypair;
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}
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void wg_noise_keypairs_clear(struct noise_keypairs *keypairs)
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{
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struct noise_keypair *old;
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spin_lock_bh(&keypairs->keypair_update_lock);
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/* We zero the next_keypair before zeroing the others, so that
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* wg_noise_received_with_keypair returns early before subsequent ones
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* are zeroed.
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*/
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old = rcu_dereference_protected(keypairs->next_keypair,
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lockdep_is_held(&keypairs->keypair_update_lock));
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RCU_INIT_POINTER(keypairs->next_keypair, NULL);
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wg_noise_keypair_put(old, true);
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old = rcu_dereference_protected(keypairs->previous_keypair,
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lockdep_is_held(&keypairs->keypair_update_lock));
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RCU_INIT_POINTER(keypairs->previous_keypair, NULL);
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wg_noise_keypair_put(old, true);
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old = rcu_dereference_protected(keypairs->current_keypair,
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lockdep_is_held(&keypairs->keypair_update_lock));
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RCU_INIT_POINTER(keypairs->current_keypair, NULL);
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wg_noise_keypair_put(old, true);
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spin_unlock_bh(&keypairs->keypair_update_lock);
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}
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void wg_noise_expire_current_peer_keypairs(struct wg_peer *peer)
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{
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struct noise_keypair *keypair;
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wg_noise_handshake_clear(&peer->handshake);
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wg_noise_reset_last_sent_handshake(&peer->last_sent_handshake);
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spin_lock_bh(&peer->keypairs.keypair_update_lock);
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keypair = rcu_dereference_protected(peer->keypairs.next_keypair,
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lockdep_is_held(&peer->keypairs.keypair_update_lock));
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if (keypair)
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keypair->sending.is_valid = false;
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keypair = rcu_dereference_protected(peer->keypairs.current_keypair,
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lockdep_is_held(&peer->keypairs.keypair_update_lock));
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if (keypair)
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keypair->sending.is_valid = false;
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spin_unlock_bh(&peer->keypairs.keypair_update_lock);
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}
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static void add_new_keypair(struct noise_keypairs *keypairs,
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struct noise_keypair *new_keypair)
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{
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struct noise_keypair *previous_keypair, *next_keypair, *current_keypair;
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spin_lock_bh(&keypairs->keypair_update_lock);
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previous_keypair = rcu_dereference_protected(keypairs->previous_keypair,
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lockdep_is_held(&keypairs->keypair_update_lock));
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next_keypair = rcu_dereference_protected(keypairs->next_keypair,
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lockdep_is_held(&keypairs->keypair_update_lock));
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current_keypair = rcu_dereference_protected(keypairs->current_keypair,
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lockdep_is_held(&keypairs->keypair_update_lock));
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if (new_keypair->i_am_the_initiator) {
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/* If we're the initiator, it means we've sent a handshake, and
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* received a confirmation response, which means this new
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* keypair can now be used.
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*/
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if (next_keypair) {
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/* If there already was a next keypair pending, we
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* demote it to be the previous keypair, and free the
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* existing current. Note that this means KCI can result
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* in this transition. It would perhaps be more sound to
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* always just get rid of the unused next keypair
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* instead of putting it in the previous slot, but this
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* might be a bit less robust. Something to think about
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* for the future.
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*/
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RCU_INIT_POINTER(keypairs->next_keypair, NULL);
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rcu_assign_pointer(keypairs->previous_keypair,
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next_keypair);
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wg_noise_keypair_put(current_keypair, true);
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} else /* If there wasn't an existing next keypair, we replace
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* the previous with the current one.
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*/
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rcu_assign_pointer(keypairs->previous_keypair,
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current_keypair);
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/* At this point we can get rid of the old previous keypair, and
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* set up the new keypair.
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*/
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wg_noise_keypair_put(previous_keypair, true);
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rcu_assign_pointer(keypairs->current_keypair, new_keypair);
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} else {
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/* If we're the responder, it means we can't use the new keypair
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* until we receive confirmation via the first data packet, so
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* we get rid of the existing previous one, the possibly
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* existing next one, and slide in the new next one.
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*/
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rcu_assign_pointer(keypairs->next_keypair, new_keypair);
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wg_noise_keypair_put(next_keypair, true);
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RCU_INIT_POINTER(keypairs->previous_keypair, NULL);
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wg_noise_keypair_put(previous_keypair, true);
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}
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spin_unlock_bh(&keypairs->keypair_update_lock);
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}
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bool wg_noise_received_with_keypair(struct noise_keypairs *keypairs,
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struct noise_keypair *received_keypair)
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{
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struct noise_keypair *old_keypair;
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bool key_is_new;
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/* We first check without taking the spinlock. */
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key_is_new = received_keypair ==
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rcu_access_pointer(keypairs->next_keypair);
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if (likely(!key_is_new))
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return false;
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spin_lock_bh(&keypairs->keypair_update_lock);
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/* After locking, we double check that things didn't change from
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* beneath us.
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*/
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if (unlikely(received_keypair !=
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rcu_dereference_protected(keypairs->next_keypair,
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lockdep_is_held(&keypairs->keypair_update_lock)))) {
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spin_unlock_bh(&keypairs->keypair_update_lock);
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return false;
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}
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/* When we've finally received the confirmation, we slide the next
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* into the current, the current into the previous, and get rid of
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* the old previous.
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*/
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old_keypair = rcu_dereference_protected(keypairs->previous_keypair,
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lockdep_is_held(&keypairs->keypair_update_lock));
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rcu_assign_pointer(keypairs->previous_keypair,
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rcu_dereference_protected(keypairs->current_keypair,
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lockdep_is_held(&keypairs->keypair_update_lock)));
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wg_noise_keypair_put(old_keypair, true);
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rcu_assign_pointer(keypairs->current_keypair, received_keypair);
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RCU_INIT_POINTER(keypairs->next_keypair, NULL);
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spin_unlock_bh(&keypairs->keypair_update_lock);
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return true;
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}
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/* Must hold static_identity->lock */
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void wg_noise_set_static_identity_private_key(
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struct noise_static_identity *static_identity,
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const u8 private_key[NOISE_PUBLIC_KEY_LEN])
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{
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memcpy(static_identity->static_private, private_key,
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NOISE_PUBLIC_KEY_LEN);
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curve25519_clamp_secret(static_identity->static_private);
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static_identity->has_identity = curve25519_generate_public(
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static_identity->static_public, private_key);
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}
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/* This is Hugo Krawczyk's HKDF:
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* - https://eprint.iacr.org/2010/264.pdf
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* - https://tools.ietf.org/html/rfc5869
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*/
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static void kdf(u8 *first_dst, u8 *second_dst, u8 *third_dst, const u8 *data,
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size_t first_len, size_t second_len, size_t third_len,
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size_t data_len, const u8 chaining_key[NOISE_HASH_LEN])
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{
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u8 output[BLAKE2S_HASH_SIZE + 1];
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u8 secret[BLAKE2S_HASH_SIZE];
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WARN_ON(IS_ENABLED(DEBUG) &&
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(first_len > BLAKE2S_HASH_SIZE ||
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second_len > BLAKE2S_HASH_SIZE ||
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third_len > BLAKE2S_HASH_SIZE ||
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((second_len || second_dst || third_len || third_dst) &&
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(!first_len || !first_dst)) ||
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((third_len || third_dst) && (!second_len || !second_dst))));
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/* Extract entropy from data into secret */
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blake2s256_hmac(secret, data, chaining_key, data_len, NOISE_HASH_LEN);
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if (!first_dst || !first_len)
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goto out;
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/* Expand first key: key = secret, data = 0x1 */
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output[0] = 1;
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blake2s256_hmac(output, output, secret, 1, BLAKE2S_HASH_SIZE);
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memcpy(first_dst, output, first_len);
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if (!second_dst || !second_len)
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goto out;
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/* Expand second key: key = secret, data = first-key || 0x2 */
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output[BLAKE2S_HASH_SIZE] = 2;
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blake2s256_hmac(output, output, secret, BLAKE2S_HASH_SIZE + 1,
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BLAKE2S_HASH_SIZE);
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memcpy(second_dst, output, second_len);
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if (!third_dst || !third_len)
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goto out;
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/* Expand third key: key = secret, data = second-key || 0x3 */
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output[BLAKE2S_HASH_SIZE] = 3;
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blake2s256_hmac(output, output, secret, BLAKE2S_HASH_SIZE + 1,
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BLAKE2S_HASH_SIZE);
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memcpy(third_dst, output, third_len);
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out:
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/* Clear sensitive data from stack */
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memzero_explicit(secret, BLAKE2S_HASH_SIZE);
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memzero_explicit(output, BLAKE2S_HASH_SIZE + 1);
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}
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static void derive_keys(struct noise_symmetric_key *first_dst,
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struct noise_symmetric_key *second_dst,
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const u8 chaining_key[NOISE_HASH_LEN])
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{
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u64 birthdate = ktime_get_coarse_boottime_ns();
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kdf(first_dst->key, second_dst->key, NULL, NULL,
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NOISE_SYMMETRIC_KEY_LEN, NOISE_SYMMETRIC_KEY_LEN, 0, 0,
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chaining_key);
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first_dst->birthdate = second_dst->birthdate = birthdate;
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first_dst->is_valid = second_dst->is_valid = true;
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}
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static bool __must_check mix_dh(u8 chaining_key[NOISE_HASH_LEN],
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u8 key[NOISE_SYMMETRIC_KEY_LEN],
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const u8 private[NOISE_PUBLIC_KEY_LEN],
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const u8 public[NOISE_PUBLIC_KEY_LEN])
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{
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u8 dh_calculation[NOISE_PUBLIC_KEY_LEN];
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if (unlikely(!curve25519(dh_calculation, private, public)))
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return false;
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kdf(chaining_key, key, NULL, dh_calculation, NOISE_HASH_LEN,
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NOISE_SYMMETRIC_KEY_LEN, 0, NOISE_PUBLIC_KEY_LEN, chaining_key);
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memzero_explicit(dh_calculation, NOISE_PUBLIC_KEY_LEN);
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return true;
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}
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static bool __must_check mix_precomputed_dh(u8 chaining_key[NOISE_HASH_LEN],
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u8 key[NOISE_SYMMETRIC_KEY_LEN],
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const u8 precomputed[NOISE_PUBLIC_KEY_LEN])
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{
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static u8 zero_point[NOISE_PUBLIC_KEY_LEN];
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if (unlikely(!crypto_memneq(precomputed, zero_point, NOISE_PUBLIC_KEY_LEN)))
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return false;
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kdf(chaining_key, key, NULL, precomputed, NOISE_HASH_LEN,
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NOISE_SYMMETRIC_KEY_LEN, 0, NOISE_PUBLIC_KEY_LEN,
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chaining_key);
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return true;
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}
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static void mix_hash(u8 hash[NOISE_HASH_LEN], const u8 *src, size_t src_len)
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{
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struct blake2s_state blake;
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blake2s_init(&blake, NOISE_HASH_LEN);
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blake2s_update(&blake, hash, NOISE_HASH_LEN);
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blake2s_update(&blake, src, src_len);
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blake2s_final(&blake, hash);
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}
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static void mix_psk(u8 chaining_key[NOISE_HASH_LEN], u8 hash[NOISE_HASH_LEN],
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u8 key[NOISE_SYMMETRIC_KEY_LEN],
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const u8 psk[NOISE_SYMMETRIC_KEY_LEN])
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{
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u8 temp_hash[NOISE_HASH_LEN];
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kdf(chaining_key, temp_hash, key, psk, NOISE_HASH_LEN, NOISE_HASH_LEN,
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NOISE_SYMMETRIC_KEY_LEN, NOISE_SYMMETRIC_KEY_LEN, chaining_key);
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mix_hash(hash, temp_hash, NOISE_HASH_LEN);
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memzero_explicit(temp_hash, NOISE_HASH_LEN);
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}
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static void handshake_init(u8 chaining_key[NOISE_HASH_LEN],
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u8 hash[NOISE_HASH_LEN],
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const u8 remote_static[NOISE_PUBLIC_KEY_LEN])
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{
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memcpy(hash, handshake_init_hash, NOISE_HASH_LEN);
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|
memcpy(chaining_key, handshake_init_chaining_key, NOISE_HASH_LEN);
|
|
mix_hash(hash, remote_static, NOISE_PUBLIC_KEY_LEN);
|
|
}
|
|
|
|
static void message_encrypt(u8 *dst_ciphertext, const u8 *src_plaintext,
|
|
size_t src_len, u8 key[NOISE_SYMMETRIC_KEY_LEN],
|
|
u8 hash[NOISE_HASH_LEN])
|
|
{
|
|
chacha20poly1305_encrypt(dst_ciphertext, src_plaintext, src_len, hash,
|
|
NOISE_HASH_LEN,
|
|
0 /* Always zero for Noise_IK */, key);
|
|
mix_hash(hash, dst_ciphertext, noise_encrypted_len(src_len));
|
|
}
|
|
|
|
static bool message_decrypt(u8 *dst_plaintext, const u8 *src_ciphertext,
|
|
size_t src_len, u8 key[NOISE_SYMMETRIC_KEY_LEN],
|
|
u8 hash[NOISE_HASH_LEN])
|
|
{
|
|
if (!chacha20poly1305_decrypt(dst_plaintext, src_ciphertext, src_len,
|
|
hash, NOISE_HASH_LEN,
|
|
0 /* Always zero for Noise_IK */, key))
|
|
return false;
|
|
mix_hash(hash, src_ciphertext, src_len);
|
|
return true;
|
|
}
|
|
|
|
static void message_ephemeral(u8 ephemeral_dst[NOISE_PUBLIC_KEY_LEN],
|
|
const u8 ephemeral_src[NOISE_PUBLIC_KEY_LEN],
|
|
u8 chaining_key[NOISE_HASH_LEN],
|
|
u8 hash[NOISE_HASH_LEN])
|
|
{
|
|
if (ephemeral_dst != ephemeral_src)
|
|
memcpy(ephemeral_dst, ephemeral_src, NOISE_PUBLIC_KEY_LEN);
|
|
mix_hash(hash, ephemeral_src, NOISE_PUBLIC_KEY_LEN);
|
|
kdf(chaining_key, NULL, NULL, ephemeral_src, NOISE_HASH_LEN, 0, 0,
|
|
NOISE_PUBLIC_KEY_LEN, chaining_key);
|
|
}
|
|
|
|
static void tai64n_now(u8 output[NOISE_TIMESTAMP_LEN])
|
|
{
|
|
struct timespec64 now;
|
|
|
|
ktime_get_real_ts64(&now);
|
|
|
|
/* In order to prevent some sort of infoleak from precise timers, we
|
|
* round down the nanoseconds part to the closest rounded-down power of
|
|
* two to the maximum initiations per second allowed anyway by the
|
|
* implementation.
|
|
*/
|
|
now.tv_nsec = ALIGN_DOWN(now.tv_nsec,
|
|
rounddown_pow_of_two(NSEC_PER_SEC / INITIATIONS_PER_SECOND));
|
|
|
|
/* https://cr.yp.to/libtai/tai64.html */
|
|
*(__be64 *)output = cpu_to_be64(0x400000000000000aULL + now.tv_sec);
|
|
*(__be32 *)(output + sizeof(__be64)) = cpu_to_be32(now.tv_nsec);
|
|
}
|
|
|
|
bool
|
|
wg_noise_handshake_create_initiation(struct message_handshake_initiation *dst,
|
|
struct noise_handshake *handshake)
|
|
{
|
|
u8 timestamp[NOISE_TIMESTAMP_LEN];
|
|
u8 key[NOISE_SYMMETRIC_KEY_LEN];
|
|
bool ret = false;
|
|
|
|
/* We need to wait for crng _before_ taking any locks, since
|
|
* curve25519_generate_secret uses get_random_bytes_wait.
|
|
*/
|
|
wait_for_random_bytes();
|
|
|
|
down_read(&handshake->static_identity->lock);
|
|
down_write(&handshake->lock);
|
|
|
|
if (unlikely(!handshake->static_identity->has_identity))
|
|
goto out;
|
|
|
|
dst->header.type = cpu_to_le32(MESSAGE_HANDSHAKE_INITIATION);
|
|
|
|
handshake_init(handshake->chaining_key, handshake->hash,
|
|
handshake->remote_static);
|
|
|
|
/* e */
|
|
curve25519_generate_secret(handshake->ephemeral_private);
|
|
if (!curve25519_generate_public(dst->unencrypted_ephemeral,
|
|
handshake->ephemeral_private))
|
|
goto out;
|
|
message_ephemeral(dst->unencrypted_ephemeral,
|
|
dst->unencrypted_ephemeral, handshake->chaining_key,
|
|
handshake->hash);
|
|
|
|
/* es */
|
|
if (!mix_dh(handshake->chaining_key, key, handshake->ephemeral_private,
|
|
handshake->remote_static))
|
|
goto out;
|
|
|
|
/* s */
|
|
message_encrypt(dst->encrypted_static,
|
|
handshake->static_identity->static_public,
|
|
NOISE_PUBLIC_KEY_LEN, key, handshake->hash);
|
|
|
|
/* ss */
|
|
if (!mix_precomputed_dh(handshake->chaining_key, key,
|
|
handshake->precomputed_static_static))
|
|
goto out;
|
|
|
|
/* {t} */
|
|
tai64n_now(timestamp);
|
|
message_encrypt(dst->encrypted_timestamp, timestamp,
|
|
NOISE_TIMESTAMP_LEN, key, handshake->hash);
|
|
|
|
dst->sender_index = wg_index_hashtable_insert(
|
|
handshake->entry.peer->device->index_hashtable,
|
|
&handshake->entry);
|
|
|
|
handshake->state = HANDSHAKE_CREATED_INITIATION;
|
|
ret = true;
|
|
|
|
out:
|
|
up_write(&handshake->lock);
|
|
up_read(&handshake->static_identity->lock);
|
|
memzero_explicit(key, NOISE_SYMMETRIC_KEY_LEN);
|
|
return ret;
|
|
}
|
|
|
|
struct wg_peer *
|
|
wg_noise_handshake_consume_initiation(struct message_handshake_initiation *src,
|
|
struct wg_device *wg)
|
|
{
|
|
struct wg_peer *peer = NULL, *ret_peer = NULL;
|
|
struct noise_handshake *handshake;
|
|
bool replay_attack, flood_attack;
|
|
u8 key[NOISE_SYMMETRIC_KEY_LEN];
|
|
u8 chaining_key[NOISE_HASH_LEN];
|
|
u8 hash[NOISE_HASH_LEN];
|
|
u8 s[NOISE_PUBLIC_KEY_LEN];
|
|
u8 e[NOISE_PUBLIC_KEY_LEN];
|
|
u8 t[NOISE_TIMESTAMP_LEN];
|
|
u64 initiation_consumption;
|
|
|
|
down_read(&wg->static_identity.lock);
|
|
if (unlikely(!wg->static_identity.has_identity))
|
|
goto out;
|
|
|
|
handshake_init(chaining_key, hash, wg->static_identity.static_public);
|
|
|
|
/* e */
|
|
message_ephemeral(e, src->unencrypted_ephemeral, chaining_key, hash);
|
|
|
|
/* es */
|
|
if (!mix_dh(chaining_key, key, wg->static_identity.static_private, e))
|
|
goto out;
|
|
|
|
/* s */
|
|
if (!message_decrypt(s, src->encrypted_static,
|
|
sizeof(src->encrypted_static), key, hash))
|
|
goto out;
|
|
|
|
/* Lookup which peer we're actually talking to */
|
|
peer = wg_pubkey_hashtable_lookup(wg->peer_hashtable, s);
|
|
if (!peer)
|
|
goto out;
|
|
handshake = &peer->handshake;
|
|
|
|
/* ss */
|
|
if (!mix_precomputed_dh(chaining_key, key,
|
|
handshake->precomputed_static_static))
|
|
goto out;
|
|
|
|
/* {t} */
|
|
if (!message_decrypt(t, src->encrypted_timestamp,
|
|
sizeof(src->encrypted_timestamp), key, hash))
|
|
goto out;
|
|
|
|
down_read(&handshake->lock);
|
|
replay_attack = memcmp(t, handshake->latest_timestamp,
|
|
NOISE_TIMESTAMP_LEN) <= 0;
|
|
flood_attack = (s64)handshake->last_initiation_consumption +
|
|
NSEC_PER_SEC / INITIATIONS_PER_SECOND >
|
|
(s64)ktime_get_coarse_boottime_ns();
|
|
up_read(&handshake->lock);
|
|
if (replay_attack || flood_attack)
|
|
goto out;
|
|
|
|
/* Success! Copy everything to peer */
|
|
down_write(&handshake->lock);
|
|
memcpy(handshake->remote_ephemeral, e, NOISE_PUBLIC_KEY_LEN);
|
|
if (memcmp(t, handshake->latest_timestamp, NOISE_TIMESTAMP_LEN) > 0)
|
|
memcpy(handshake->latest_timestamp, t, NOISE_TIMESTAMP_LEN);
|
|
memcpy(handshake->hash, hash, NOISE_HASH_LEN);
|
|
memcpy(handshake->chaining_key, chaining_key, NOISE_HASH_LEN);
|
|
handshake->remote_index = src->sender_index;
|
|
initiation_consumption = ktime_get_coarse_boottime_ns();
|
|
if ((s64)(handshake->last_initiation_consumption - initiation_consumption) < 0)
|
|
handshake->last_initiation_consumption = initiation_consumption;
|
|
handshake->state = HANDSHAKE_CONSUMED_INITIATION;
|
|
up_write(&handshake->lock);
|
|
ret_peer = peer;
|
|
|
|
out:
|
|
memzero_explicit(key, NOISE_SYMMETRIC_KEY_LEN);
|
|
memzero_explicit(hash, NOISE_HASH_LEN);
|
|
memzero_explicit(chaining_key, NOISE_HASH_LEN);
|
|
up_read(&wg->static_identity.lock);
|
|
if (!ret_peer)
|
|
wg_peer_put(peer);
|
|
return ret_peer;
|
|
}
|
|
|
|
bool wg_noise_handshake_create_response(struct message_handshake_response *dst,
|
|
struct noise_handshake *handshake)
|
|
{
|
|
u8 key[NOISE_SYMMETRIC_KEY_LEN];
|
|
bool ret = false;
|
|
|
|
/* We need to wait for crng _before_ taking any locks, since
|
|
* curve25519_generate_secret uses get_random_bytes_wait.
|
|
*/
|
|
wait_for_random_bytes();
|
|
|
|
down_read(&handshake->static_identity->lock);
|
|
down_write(&handshake->lock);
|
|
|
|
if (handshake->state != HANDSHAKE_CONSUMED_INITIATION)
|
|
goto out;
|
|
|
|
dst->header.type = cpu_to_le32(MESSAGE_HANDSHAKE_RESPONSE);
|
|
dst->receiver_index = handshake->remote_index;
|
|
|
|
/* e */
|
|
curve25519_generate_secret(handshake->ephemeral_private);
|
|
if (!curve25519_generate_public(dst->unencrypted_ephemeral,
|
|
handshake->ephemeral_private))
|
|
goto out;
|
|
message_ephemeral(dst->unencrypted_ephemeral,
|
|
dst->unencrypted_ephemeral, handshake->chaining_key,
|
|
handshake->hash);
|
|
|
|
/* ee */
|
|
if (!mix_dh(handshake->chaining_key, NULL, handshake->ephemeral_private,
|
|
handshake->remote_ephemeral))
|
|
goto out;
|
|
|
|
/* se */
|
|
if (!mix_dh(handshake->chaining_key, NULL, handshake->ephemeral_private,
|
|
handshake->remote_static))
|
|
goto out;
|
|
|
|
/* psk */
|
|
mix_psk(handshake->chaining_key, handshake->hash, key,
|
|
handshake->preshared_key);
|
|
|
|
/* {} */
|
|
message_encrypt(dst->encrypted_nothing, NULL, 0, key, handshake->hash);
|
|
|
|
dst->sender_index = wg_index_hashtable_insert(
|
|
handshake->entry.peer->device->index_hashtable,
|
|
&handshake->entry);
|
|
|
|
handshake->state = HANDSHAKE_CREATED_RESPONSE;
|
|
ret = true;
|
|
|
|
out:
|
|
up_write(&handshake->lock);
|
|
up_read(&handshake->static_identity->lock);
|
|
memzero_explicit(key, NOISE_SYMMETRIC_KEY_LEN);
|
|
return ret;
|
|
}
|
|
|
|
struct wg_peer *
|
|
wg_noise_handshake_consume_response(struct message_handshake_response *src,
|
|
struct wg_device *wg)
|
|
{
|
|
enum noise_handshake_state state = HANDSHAKE_ZEROED;
|
|
struct wg_peer *peer = NULL, *ret_peer = NULL;
|
|
struct noise_handshake *handshake;
|
|
u8 key[NOISE_SYMMETRIC_KEY_LEN];
|
|
u8 hash[NOISE_HASH_LEN];
|
|
u8 chaining_key[NOISE_HASH_LEN];
|
|
u8 e[NOISE_PUBLIC_KEY_LEN];
|
|
u8 ephemeral_private[NOISE_PUBLIC_KEY_LEN];
|
|
u8 static_private[NOISE_PUBLIC_KEY_LEN];
|
|
u8 preshared_key[NOISE_SYMMETRIC_KEY_LEN];
|
|
|
|
down_read(&wg->static_identity.lock);
|
|
|
|
if (unlikely(!wg->static_identity.has_identity))
|
|
goto out;
|
|
|
|
handshake = (struct noise_handshake *)wg_index_hashtable_lookup(
|
|
wg->index_hashtable, INDEX_HASHTABLE_HANDSHAKE,
|
|
src->receiver_index, &peer);
|
|
if (unlikely(!handshake))
|
|
goto out;
|
|
|
|
down_read(&handshake->lock);
|
|
state = handshake->state;
|
|
memcpy(hash, handshake->hash, NOISE_HASH_LEN);
|
|
memcpy(chaining_key, handshake->chaining_key, NOISE_HASH_LEN);
|
|
memcpy(ephemeral_private, handshake->ephemeral_private,
|
|
NOISE_PUBLIC_KEY_LEN);
|
|
memcpy(preshared_key, handshake->preshared_key,
|
|
NOISE_SYMMETRIC_KEY_LEN);
|
|
up_read(&handshake->lock);
|
|
|
|
if (state != HANDSHAKE_CREATED_INITIATION)
|
|
goto fail;
|
|
|
|
/* e */
|
|
message_ephemeral(e, src->unencrypted_ephemeral, chaining_key, hash);
|
|
|
|
/* ee */
|
|
if (!mix_dh(chaining_key, NULL, ephemeral_private, e))
|
|
goto fail;
|
|
|
|
/* se */
|
|
if (!mix_dh(chaining_key, NULL, wg->static_identity.static_private, e))
|
|
goto fail;
|
|
|
|
/* psk */
|
|
mix_psk(chaining_key, hash, key, preshared_key);
|
|
|
|
/* {} */
|
|
if (!message_decrypt(NULL, src->encrypted_nothing,
|
|
sizeof(src->encrypted_nothing), key, hash))
|
|
goto fail;
|
|
|
|
/* Success! Copy everything to peer */
|
|
down_write(&handshake->lock);
|
|
/* It's important to check that the state is still the same, while we
|
|
* have an exclusive lock.
|
|
*/
|
|
if (handshake->state != state) {
|
|
up_write(&handshake->lock);
|
|
goto fail;
|
|
}
|
|
memcpy(handshake->remote_ephemeral, e, NOISE_PUBLIC_KEY_LEN);
|
|
memcpy(handshake->hash, hash, NOISE_HASH_LEN);
|
|
memcpy(handshake->chaining_key, chaining_key, NOISE_HASH_LEN);
|
|
handshake->remote_index = src->sender_index;
|
|
handshake->state = HANDSHAKE_CONSUMED_RESPONSE;
|
|
up_write(&handshake->lock);
|
|
ret_peer = peer;
|
|
goto out;
|
|
|
|
fail:
|
|
wg_peer_put(peer);
|
|
out:
|
|
memzero_explicit(key, NOISE_SYMMETRIC_KEY_LEN);
|
|
memzero_explicit(hash, NOISE_HASH_LEN);
|
|
memzero_explicit(chaining_key, NOISE_HASH_LEN);
|
|
memzero_explicit(ephemeral_private, NOISE_PUBLIC_KEY_LEN);
|
|
memzero_explicit(static_private, NOISE_PUBLIC_KEY_LEN);
|
|
memzero_explicit(preshared_key, NOISE_SYMMETRIC_KEY_LEN);
|
|
up_read(&wg->static_identity.lock);
|
|
return ret_peer;
|
|
}
|
|
|
|
bool wg_noise_handshake_begin_session(struct noise_handshake *handshake,
|
|
struct noise_keypairs *keypairs)
|
|
{
|
|
struct noise_keypair *new_keypair;
|
|
bool ret = false;
|
|
|
|
down_write(&handshake->lock);
|
|
if (handshake->state != HANDSHAKE_CREATED_RESPONSE &&
|
|
handshake->state != HANDSHAKE_CONSUMED_RESPONSE)
|
|
goto out;
|
|
|
|
new_keypair = keypair_create(handshake->entry.peer);
|
|
if (!new_keypair)
|
|
goto out;
|
|
new_keypair->i_am_the_initiator = handshake->state ==
|
|
HANDSHAKE_CONSUMED_RESPONSE;
|
|
new_keypair->remote_index = handshake->remote_index;
|
|
|
|
if (new_keypair->i_am_the_initiator)
|
|
derive_keys(&new_keypair->sending, &new_keypair->receiving,
|
|
handshake->chaining_key);
|
|
else
|
|
derive_keys(&new_keypair->receiving, &new_keypair->sending,
|
|
handshake->chaining_key);
|
|
|
|
handshake_zero(handshake);
|
|
rcu_read_lock_bh();
|
|
if (likely(!READ_ONCE(container_of(handshake, struct wg_peer,
|
|
handshake)->is_dead))) {
|
|
add_new_keypair(keypairs, new_keypair);
|
|
net_dbg_ratelimited("%s: Keypair %llu created for peer %llu\n",
|
|
handshake->entry.peer->device->dev->name,
|
|
new_keypair->internal_id,
|
|
handshake->entry.peer->internal_id);
|
|
ret = wg_index_hashtable_replace(
|
|
handshake->entry.peer->device->index_hashtable,
|
|
&handshake->entry, &new_keypair->entry);
|
|
} else {
|
|
kfree_sensitive(new_keypair);
|
|
}
|
|
rcu_read_unlock_bh();
|
|
|
|
out:
|
|
up_write(&handshake->lock);
|
|
return ret;
|
|
}
|