Differential D26137 Diff 76740 sys/dev/if_wg/include/sys/wg_cookie.h

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sys/dev/if_wg/include/sys/wg_cookie.h

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				/*
				* Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
				* Copyright (C) 2019-2020 Matt Dunwoodie <ncon@noconroy.net>
				*
				* Permission to use, copy, modify, and distribute this software for any
				* purpose with or without fee is hereby granted, provided that the above
				* copyright notice and this permission notice appear in all copies.
				*
				* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
				* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
				* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
				* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
				* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
				* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
				* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
				*
				* ======== wg_cookie.h ========
				*
				* This file provides a thread safe interface to the WireGuard cookie
				* mechanism. It is split into three parts:
				*
				* * cookie_maker
				* Used to create MACs for messages.
				* * cookie_checker
				* Used to validate MACs for messages.
				* * cookie_macs
				* The MACs that authenticate the message.
				*
				* The MACs provide two properties:
				* * mac1 - That the remote end knows a value.
				* * mac2 - That the remote end has a specific IP address.
				*
				* void cookie_maker_init(cookie_maker, ipl, input)
				* - Initialise cookie_maker, should only be called once and before use.
				* input is the shared value used for mac1.
				*
				* int cookie_checker_init(cookie_checker, ipl)
				* - Initialise cookie_checker, should only be called once and before use. It
				* will return ENOBUFS if it cannot allocate required memory.
				*
				* void cookie_checker_update(cookie_checker, input)
				* - Set the input value to check mac1 against.
				*
				* void cookie_checker_deinit(cookie_checker)
				* - Destroy all values associated with cookie_checker. cookie_checker must
				* not be used after calling this function.
				*
				* void cookie_checker_create_payload(cookie_checker, cookie_macs, nonce,
				* payload, sockaddr)
				* - Create a specific payload derived from the sockaddr. The payload is an
				* encrypted shared secret, that the cookie_maker will decrypt and used to
				* key the mac2 value.
				*
				* int cookie_maker_consume_payload(cookie_maker, nonce, payload)
				* - Have cookie_maker consume the payload.
				*
				* void cookie_maker_mac(cookie_maker, cookie_macs, message, len)
				* - Create cookie_macs for the message of length len. It will always compute
				* mac1, however will only compute mac2 if we have recently received a
				* payload to key it with.
				*
				* int cookie_checker_validate_macs(cookie_checker, cookie_macs, message, len,
				* busy, sockaddr)
				* - Use cookie_checker to validate the cookie_macs of message with length
				* len. If busy, then ratelimiting will be applied to the sockaddr.
				*
				* ==========================
				*/

				#ifndef __COOKIE_H__
				#define __COOKIE_H__

				#include <sys/types.h>
				#include <sys/time.h>
				#include <sys/rwlock.h>
				#include <sys/queue.h>
				#include <sys/support.h>

				#include <netinet/in.h>

				#include <crypto/blake2s.h>

				#define COOKIE_MAC_SIZE 16
				#define COOKIE_KEY_SIZE 32
				#define COOKIE_XNONCE_SIZE 24
				#define COOKIE_COOKIE_SIZE 16
				#define COOKIE_SECRET_SIZE 32
				#define COOKIE_INPUT_SIZE 32
				#define COOKIE_ENCRYPTED_SIZE (COOKIE_COOKIE_SIZE + COOKIE_MAC_SIZE)

				#define COOKIE_MAC1_KEY_LABEL "mac1----"
				#define COOKIE_COOKIE_KEY_LABEL "cookie--"
				#define COOKIE_SECRET_MAX_AGE 120
				#define COOKIE_SECRET_LATENCY 5

				/* Constants for initiation rate limiting */
				#define RATELIMIT_SIZE (1 << 10)
				#define RATELIMIT_SIZE_MAX (RATELIMIT_SIZE * 8)
				#define NSEC_PER_SEC 1000000000LL
				#define INITIATIONS_PER_SECOND 50
				#define INITIATIONS_BURSTABLE 10
				#define INITIATION_COST (NSEC_PER_SEC / INITIATIONS_PER_SECOND)
				#define TOKEN_MAX (INITIATION_COST * INITIATIONS_BURSTABLE)
				#define ELEMENT_TIMEOUT 1
				#define IPV4_MASK_SIZE 4 /* Use all 4 bytes of IPv4 address */
				#define IPV6_MASK_SIZE 8 /* Use top 8 bytes (/64) of IPv6 address */

				struct cookie_macs {
				uint8_t mac1[COOKIE_MAC_SIZE];
				uint8_t mac2[COOKIE_MAC_SIZE];
				} __packed;

				struct ratelimit_entry {
				LIST_ENTRY(ratelimit_entry) r_entry;
				sa_family_t r_af;
				union {
				struct in_addr r_in;
				struct in6_addr r_in6;
				};
				struct timespec r_last_time; /* nanouptime */
				uint64_t r_tokens;
				};

				struct ratelimit {
				SIPHASH_KEY rl_secret;
				uma_zone_t rl_zone;

				struct rwlock rl_lock;
				LIST_HEAD(, ratelimit_entry) *rl_table;
				u_long rl_table_mask;
				size_t rl_table_num;
				struct timespec rl_last_gc; /* nanouptime */
				};

				struct cookie_maker {
				uint8_t cp_mac1_key[COOKIE_KEY_SIZE];
				uint8_t cp_cookie_key[COOKIE_KEY_SIZE];

				struct rwlock cp_lock;
				uint8_t cp_cookie[COOKIE_COOKIE_SIZE];
				struct timespec cp_birthdate; /* nanouptime */
				int cp_mac1_valid;
				uint8_t cp_mac1_last[COOKIE_MAC_SIZE];
				};

				struct cookie_checker {
				struct ratelimit cc_ratelimit;

				struct rwlock cc_key_lock;
				uint8_t cc_mac1_key[COOKIE_KEY_SIZE];
				uint8_t cc_cookie_key[COOKIE_KEY_SIZE];

				struct rwlock cc_secret_lock;
				struct timespec cc_secret_birthdate; /* nanouptime */
				uint8_t cc_secret[COOKIE_SECRET_SIZE];
				};

				void cookie_maker_init(struct cookie_maker *, const uint8_t[COOKIE_INPUT_SIZE]);
				int cookie_checker_init(struct cookie_checker *, uma_zone_t);
				void cookie_checker_update(struct cookie_checker *,
				uint8_t[COOKIE_INPUT_SIZE]);
				void cookie_checker_deinit(struct cookie_checker *);
				void cookie_checker_create_payload(struct cookie_checker *,
				struct cookie_macs *cm, uint8_t[COOKIE_XNONCE_SIZE],
				uint8_t [COOKIE_ENCRYPTED_SIZE], struct sockaddr *);
				int cookie_maker_consume_payload(struct cookie_maker *,
				uint8_t[COOKIE_XNONCE_SIZE], uint8_t[COOKIE_ENCRYPTED_SIZE]);
				void cookie_maker_mac(struct cookie_maker , struct cookie_macs ,
				void *, size_t);
				int cookie_checker_validate_macs(struct cookie_checker *,
				struct cookie_macs , void , size_t, int, struct sockaddr *);

				#endif /* __COOKIE_H__ */