xref: /openbmc/linux/drivers/net/wireguard/noise.h (revision a9e90d99)
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 
18 struct noise_replay_counter {
19 	u64 counter;
20 	spinlock_t lock;
21 	unsigned long backtrack[COUNTER_BITS_TOTAL / BITS_PER_LONG];
22 };
23 
24 struct noise_symmetric_key {
25 	u8 key[NOISE_SYMMETRIC_KEY_LEN];
26 	u64 birthdate;
27 	bool is_valid;
28 };
29 
30 struct 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 
43 struct 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 
50 struct 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 
57 enum noise_handshake_state {
58 	HANDSHAKE_ZEROED,
59 	HANDSHAKE_CREATED_INITIATION,
60 	HANDSHAKE_CONSUMED_INITIATION,
61 	HANDSHAKE_CREATED_RESPONSE,
62 	HANDSHAKE_CONSUMED_RESPONSE
63 };
64 
65 struct 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 
92 struct wg_device;
93 
94 void wg_noise_init(void);
95 void 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);
100 void wg_noise_handshake_clear(struct noise_handshake *handshake);
wg_noise_reset_last_sent_handshake(atomic64_t * handshake_ns)101 static 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 
107 void wg_noise_keypair_put(struct noise_keypair *keypair, bool unreference_now);
108 struct noise_keypair *wg_noise_keypair_get(struct noise_keypair *keypair);
109 void wg_noise_keypairs_clear(struct noise_keypairs *keypairs);
110 bool wg_noise_received_with_keypair(struct noise_keypairs *keypairs,
111 				    struct noise_keypair *received_keypair);
112 void wg_noise_expire_current_peer_keypairs(struct wg_peer *peer);
113 
114 void wg_noise_set_static_identity_private_key(
115 	struct noise_static_identity *static_identity,
116 	const u8 private_key[NOISE_PUBLIC_KEY_LEN]);
117 void wg_noise_precompute_static_static(struct wg_peer *peer);
118 
119 bool
120 wg_noise_handshake_create_initiation(struct message_handshake_initiation *dst,
121 				     struct noise_handshake *handshake);
122 struct wg_peer *
123 wg_noise_handshake_consume_initiation(struct message_handshake_initiation *src,
124 				      struct wg_device *wg);
125 
126 bool wg_noise_handshake_create_response(struct message_handshake_response *dst,
127 					struct noise_handshake *handshake);
128 struct wg_peer *
129 wg_noise_handshake_consume_response(struct message_handshake_response *src,
130 				    struct wg_device *wg);
131 
132 bool wg_noise_handshake_begin_session(struct noise_handshake *handshake,
133 				      struct noise_keypairs *keypairs);
134 
135 #endif /* _WG_NOISE_H */
136