110 lines
3.1 KiB
C
110 lines
3.1 KiB
C
/* Copyright (C) CZ.NIC, z.s.p.o. <knot-resolver@labs.nic.cz>
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* SPDX-License-Identifier: GPL-3.0-or-later
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*/
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#include <nettle/hmac.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <libknot/errcode.h>
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#include <libknot/rrtype/opt-cookie.h>
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#include "lib/cookies/alg_sha.h"
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#include "lib/utils.h"
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/**
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* @brief Update hash value.
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*
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* @param ctx HMAC-SHA256 context to be updated.
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* @param sa Socket address.
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*/
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static inline void update_hash(struct hmac_sha256_ctx *ctx,
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const struct sockaddr *sa)
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{
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if (kr_fails_assert(ctx && sa))
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return;
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int addr_len = kr_inaddr_len(sa);
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const uint8_t *addr = (uint8_t *)kr_inaddr(sa);
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if (addr && addr_len > 0) {
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hmac_sha256_update(ctx, addr_len, addr);
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}
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}
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/**
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* @brief Compute client cookie using HMAC-SHA256-64.
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* @note At least one of the arguments must be non-null.
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* @param input input parameters
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* @param cc_out buffer for computed client cookie
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* @param cc_len buffer size
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* @return Non-zero size of written data on success, 0 in case of a failure.
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*/
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static uint16_t cc_gen_hmac_sha256_64(const struct knot_cc_input *input,
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uint8_t *cc_out, uint16_t cc_len)
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{
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if (!knot_cc_input_is_valid(input) ||
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!cc_out || cc_len < KNOT_OPT_COOKIE_CLNT) {
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return 0;
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}
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struct hmac_sha256_ctx ctx;
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hmac_sha256_set_key(&ctx, input->secret_len, input->secret_data);
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if (input->clnt_sockaddr) {
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update_hash(&ctx, input->clnt_sockaddr);
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}
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if (input->srvr_sockaddr) {
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update_hash(&ctx, input->srvr_sockaddr);
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}
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/* KNOT_OPT_COOKIE_CLNT <= SHA256_DIGEST_SIZE */
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hmac_sha256_digest(&ctx, KNOT_OPT_COOKIE_CLNT, cc_out);
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return KNOT_OPT_COOKIE_CLNT;
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}
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#define SRVR_HMAC_SHA256_64_HASH_SIZE 8
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/**
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* @brief Compute server cookie hash using HMAC-SHA256-64).
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* @note Server cookie = nonce | time | HMAC-SHA256-64( server secret, client cookie | nonce| time | client IP )
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* @param input data to compute cookie from
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* @param hash_out hash output buffer
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* @param hash_len buffer size
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* @return Non-zero size of written data on success, 0 in case of a failure.
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*/
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static uint16_t sc_gen_hmac_sha256_64(const struct knot_sc_input *input,
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uint8_t *hash_out, uint16_t hash_len)
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{
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if (!knot_sc_input_is_valid(input) ||
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!hash_out || hash_len < SRVR_HMAC_SHA256_64_HASH_SIZE) {
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return 0;
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}
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struct hmac_sha256_ctx ctx;
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hmac_sha256_set_key(&ctx, input->srvr_data->secret_len,
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input->srvr_data->secret_data);
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hmac_sha256_update(&ctx, input->cc_len, input->cc);
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if (input->nonce && input->nonce_len) {
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hmac_sha256_update(&ctx, input->nonce_len, input->nonce);
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}
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if (input->srvr_data->clnt_sockaddr) {
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update_hash(&ctx, input->srvr_data->clnt_sockaddr);
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}
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/* SRVR_HMAC_SHA256_64_HASH_SIZE < SHA256_DIGEST_SIZE */
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hmac_sha256_digest(&ctx, SRVR_HMAC_SHA256_64_HASH_SIZE, hash_out);
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return SRVR_HMAC_SHA256_64_HASH_SIZE;
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}
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const struct knot_cc_alg knot_cc_alg_hmac_sha256_64 = { KNOT_OPT_COOKIE_CLNT, cc_gen_hmac_sha256_64 };
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const struct knot_sc_alg knot_sc_alg_hmac_sha256_64 = { SRVR_HMAC_SHA256_64_HASH_SIZE, sc_gen_hmac_sha256_64 };
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