1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
4 */
5#ifndef _WG_NOISE_H
6#define _WG_NOISE_H
7
8#include "messages.h"
9#include "peerlookup.h"
10
11#include <linux/types.h>
12#include <linux/spinlock.h>
13#include <linux/atomic.h>
14#include <linux/rwsem.h>
15#include <linux/mutex.h>
16#include <linux/kref.h>
17
18struct noise_replay_counter {
19	u64 counter;
20	spinlock_t lock;
21	unsigned long backtrack[COUNTER_BITS_TOTAL / BITS_PER_LONG];
22};
23
24struct noise_symmetric_key {
25	u8 key[NOISE_SYMMETRIC_KEY_LEN];
26	u64 birthdate;
27	bool is_valid;
28};
29
30struct noise_keypair {
31	struct index_hashtable_entry entry;
32	struct noise_symmetric_key sending;
33	atomic64_t sending_counter;
34	struct noise_symmetric_key receiving;
35	struct noise_replay_counter receiving_counter;
36	__le32 remote_index;
37	bool i_am_the_initiator;
38	struct kref refcount;
39	struct rcu_head rcu;
40	u64 internal_id;
41};
42
43struct noise_keypairs {
44	struct noise_keypair __rcu *current_keypair;
45	struct noise_keypair __rcu *previous_keypair;
46	struct noise_keypair __rcu *next_keypair;
47	spinlock_t keypair_update_lock;
48};
49
50struct noise_static_identity {
51	u8 static_public[NOISE_PUBLIC_KEY_LEN];
52	u8 static_private[NOISE_PUBLIC_KEY_LEN];
53	struct rw_semaphore lock;
54	bool has_identity;
55};
56
57enum noise_handshake_state {
58	HANDSHAKE_ZEROED,
59	HANDSHAKE_CREATED_INITIATION,
60	HANDSHAKE_CONSUMED_INITIATION,
61	HANDSHAKE_CREATED_RESPONSE,
62	HANDSHAKE_CONSUMED_RESPONSE
63};
64
65struct noise_handshake {
66	struct index_hashtable_entry entry;
67
68	enum noise_handshake_state state;
69	u64 last_initiation_consumption;
70
71	struct noise_static_identity *static_identity;
72
73	u8 ephemeral_private[NOISE_PUBLIC_KEY_LEN];
74	u8 remote_static[NOISE_PUBLIC_KEY_LEN];
75	u8 remote_ephemeral[NOISE_PUBLIC_KEY_LEN];
76	u8 precomputed_static_static[NOISE_PUBLIC_KEY_LEN];
77
78	u8 preshared_key[NOISE_SYMMETRIC_KEY_LEN];
79
80	u8 hash[NOISE_HASH_LEN];
81	u8 chaining_key[NOISE_HASH_LEN];
82
83	u8 latest_timestamp[NOISE_TIMESTAMP_LEN];
84	__le32 remote_index;
85
86	/* Protects all members except the immutable (after noise_handshake_
87	 * init): remote_static, precomputed_static_static, static_identity.
88	 */
89	struct rw_semaphore lock;
90};
91
92struct wg_device;
93
94void wg_noise_init(void);
95void wg_noise_handshake_init(struct noise_handshake *handshake,
96			     struct noise_static_identity *static_identity,
97			     const u8 peer_public_key[NOISE_PUBLIC_KEY_LEN],
98			     const u8 peer_preshared_key[NOISE_SYMMETRIC_KEY_LEN],
99			     struct wg_peer *peer);
100void wg_noise_handshake_clear(struct noise_handshake *handshake);
101static inline void wg_noise_reset_last_sent_handshake(atomic64_t *handshake_ns)
102{
103	atomic64_set(handshake_ns, ktime_get_coarse_boottime_ns() -
104				       (u64)(REKEY_TIMEOUT + 1) * NSEC_PER_SEC);
105}
106
107void wg_noise_keypair_put(struct noise_keypair *keypair, bool unreference_now);
108struct noise_keypair *wg_noise_keypair_get(struct noise_keypair *keypair);
109void wg_noise_keypairs_clear(struct noise_keypairs *keypairs);
110bool wg_noise_received_with_keypair(struct noise_keypairs *keypairs,
111				    struct noise_keypair *received_keypair);
112void wg_noise_expire_current_peer_keypairs(struct wg_peer *peer);
113
114void wg_noise_set_static_identity_private_key(
115	struct noise_static_identity *static_identity,
116	const u8 private_key[NOISE_PUBLIC_KEY_LEN]);
117void wg_noise_precompute_static_static(struct wg_peer *peer);
118
119bool
120wg_noise_handshake_create_initiation(struct message_handshake_initiation *dst,
121				     struct noise_handshake *handshake);
122struct wg_peer *
123wg_noise_handshake_consume_initiation(struct message_handshake_initiation *src,
124				      struct wg_device *wg);
125
126bool wg_noise_handshake_create_response(struct message_handshake_response *dst,
127					struct noise_handshake *handshake);
128struct wg_peer *
129wg_noise_handshake_consume_response(struct message_handshake_response *src,
130				    struct wg_device *wg);
131
132bool wg_noise_handshake_begin_session(struct noise_handshake *handshake,
133				      struct noise_keypairs *keypairs);
134
135#endif /* _WG_NOISE_H */
136