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a9e90d9931
In "wireguard: queueing: preserve flow hash across packet scrubbing", we
were required to slightly increase the size of the receive replay
counter to something still fairly small, but an increase nonetheless.
It turns out that we can recoup some of the additional memory overhead
by splitting up the prior union type into two distinct types. Before, we
used the same "noise_counter" union for both sending and receiving, with
sending just using a simple atomic64_t, while receiving used the full
replay counter checker. This meant that most of the memory being
allocated for the sending counter was being wasted. Since the old
"noise_counter" type increased in size in the prior commit, now is a
good time to split up that union type into a distinct "noise_replay_
counter" for receiving and a boring atomic64_t for sending, each using
neither more nor less memory than required.
Also, since sometimes the replay counter is accessed without
necessitating additional accesses to the bitmap, we can reduce cache
misses by hoisting the always-necessary lock above the bitmap in the
struct layout. We also change a "noise_replay_counter" stack allocation
to kmalloc in a -DDEBUG selftest so that KASAN doesn't trigger a stack
frame warning.
All and all, removing a bit of abstraction in this commit makes the code
simpler and smaller, in addition to the motivating memory usage
recuperation. For example, passing around raw "noise_symmetric_key"
structs is something that really only makes sense within noise.c, in the
one place where the sending and receiving keys can safely be thought of
as the same type of object; subsequent to that, it's important that we
uniformly access these through keypair->{sending,receiving}, where their
distinct roles are always made explicit. So this patch allows us to draw
that distinction clearly as well.
Fixes: e7096c131e ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
135 lines
3.9 KiB
C
135 lines
3.9 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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#ifndef _WG_NOISE_H
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#define _WG_NOISE_H
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#include "messages.h"
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#include "peerlookup.h"
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#include <linux/types.h>
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#include <linux/spinlock.h>
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#include <linux/atomic.h>
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#include <linux/rwsem.h>
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#include <linux/mutex.h>
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#include <linux/kref.h>
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struct noise_replay_counter {
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u64 counter;
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spinlock_t lock;
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unsigned long backtrack[COUNTER_BITS_TOTAL / BITS_PER_LONG];
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};
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struct noise_symmetric_key {
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u8 key[NOISE_SYMMETRIC_KEY_LEN];
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u64 birthdate;
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bool is_valid;
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};
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struct noise_keypair {
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struct index_hashtable_entry entry;
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struct noise_symmetric_key sending;
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atomic64_t sending_counter;
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struct noise_symmetric_key receiving;
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struct noise_replay_counter receiving_counter;
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__le32 remote_index;
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bool i_am_the_initiator;
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struct kref refcount;
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struct rcu_head rcu;
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u64 internal_id;
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};
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struct noise_keypairs {
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struct noise_keypair __rcu *current_keypair;
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struct noise_keypair __rcu *previous_keypair;
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struct noise_keypair __rcu *next_keypair;
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spinlock_t keypair_update_lock;
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};
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struct noise_static_identity {
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u8 static_public[NOISE_PUBLIC_KEY_LEN];
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u8 static_private[NOISE_PUBLIC_KEY_LEN];
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struct rw_semaphore lock;
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bool has_identity;
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};
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enum noise_handshake_state {
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HANDSHAKE_ZEROED,
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HANDSHAKE_CREATED_INITIATION,
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HANDSHAKE_CONSUMED_INITIATION,
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HANDSHAKE_CREATED_RESPONSE,
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HANDSHAKE_CONSUMED_RESPONSE
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};
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struct noise_handshake {
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struct index_hashtable_entry entry;
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enum noise_handshake_state state;
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u64 last_initiation_consumption;
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struct noise_static_identity *static_identity;
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u8 ephemeral_private[NOISE_PUBLIC_KEY_LEN];
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u8 remote_static[NOISE_PUBLIC_KEY_LEN];
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u8 remote_ephemeral[NOISE_PUBLIC_KEY_LEN];
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u8 precomputed_static_static[NOISE_PUBLIC_KEY_LEN];
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u8 preshared_key[NOISE_SYMMETRIC_KEY_LEN];
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u8 hash[NOISE_HASH_LEN];
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u8 chaining_key[NOISE_HASH_LEN];
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u8 latest_timestamp[NOISE_TIMESTAMP_LEN];
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__le32 remote_index;
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/* Protects all members except the immutable (after noise_handshake_
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* init): remote_static, precomputed_static_static, static_identity.
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*/
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struct rw_semaphore lock;
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};
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struct wg_device;
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void wg_noise_init(void);
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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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void wg_noise_handshake_clear(struct noise_handshake *handshake);
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static inline void wg_noise_reset_last_sent_handshake(atomic64_t *handshake_ns)
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{
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atomic64_set(handshake_ns, ktime_get_coarse_boottime_ns() -
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(u64)(REKEY_TIMEOUT + 1) * NSEC_PER_SEC);
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}
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void wg_noise_keypair_put(struct noise_keypair *keypair, bool unreference_now);
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struct noise_keypair *wg_noise_keypair_get(struct noise_keypair *keypair);
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void wg_noise_keypairs_clear(struct noise_keypairs *keypairs);
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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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void wg_noise_expire_current_peer_keypairs(struct wg_peer *peer);
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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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void wg_noise_precompute_static_static(struct wg_peer *peer);
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bool
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wg_noise_handshake_create_initiation(struct message_handshake_initiation *dst,
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struct noise_handshake *handshake);
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struct wg_peer *
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wg_noise_handshake_consume_initiation(struct message_handshake_initiation *src,
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struct wg_device *wg);
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bool wg_noise_handshake_create_response(struct message_handshake_response *dst,
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struct noise_handshake *handshake);
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struct wg_peer *
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wg_noise_handshake_consume_response(struct message_handshake_response *src,
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struct wg_device *wg);
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bool wg_noise_handshake_begin_session(struct noise_handshake *handshake,
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struct noise_keypairs *keypairs);
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#endif /* _WG_NOISE_H */
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