drivers/net/wireguard/noise.h

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