355 lines
8.3 KiB
C
Executable file
355 lines
8.3 KiB
C
Executable file
/* $OpenBSD: ssl_sigalgs.c,v 1.41 2022/02/05 14:54:10 jsing Exp $ */
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/*
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* Copyright (c) 2018-2020 Bob Beck <beck@openbsd.org>
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* Copyright (c) 2021 Joel Sing <jsing@openbsd.org>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <string.h>
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#include <stdlib.h>
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#include <openssl/evp.h>
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#include <openssl/opensslconf.h>
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#include "bytestring.h"
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#include "ssl_locl.h"
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#include "ssl_sigalgs.h"
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#include "tls13_internal.h"
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const struct ssl_sigalg sigalgs[] = {
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{
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.value = SIGALG_RSA_PKCS1_SHA512,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha512,
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},
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{
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.value = SIGALG_ECDSA_SECP521R1_SHA512,
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.key_type = EVP_PKEY_EC,
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.md = EVP_sha512,
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.curve_nid = NID_secp521r1,
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},
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#ifndef OPENSSL_NO_GOST
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{
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.value = SIGALG_GOSTR12_512_STREEBOG_512,
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.key_type = EVP_PKEY_GOSTR12_512,
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.md = EVP_streebog512,
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},
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#endif
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{
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.value = SIGALG_RSA_PKCS1_SHA384,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha384,
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},
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{
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.value = SIGALG_ECDSA_SECP384R1_SHA384,
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.key_type = EVP_PKEY_EC,
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.md = EVP_sha384,
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.curve_nid = NID_secp384r1,
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},
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{
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.value = SIGALG_RSA_PKCS1_SHA256,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha256,
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},
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{
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.value = SIGALG_ECDSA_SECP256R1_SHA256,
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.key_type = EVP_PKEY_EC,
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.md = EVP_sha256,
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.curve_nid = NID_X9_62_prime256v1,
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},
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#ifndef OPENSSL_NO_GOST
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{
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.value = SIGALG_GOSTR12_256_STREEBOG_256,
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.key_type = EVP_PKEY_GOSTR12_256,
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.md = EVP_streebog256,
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},
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{
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.value = SIGALG_GOSTR01_GOST94,
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.key_type = EVP_PKEY_GOSTR01,
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.md = EVP_gostr341194,
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},
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#endif
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{
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.value = SIGALG_RSA_PSS_RSAE_SHA256,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha256,
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.flags = SIGALG_FLAG_RSA_PSS,
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},
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{
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.value = SIGALG_RSA_PSS_RSAE_SHA384,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha384,
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.flags = SIGALG_FLAG_RSA_PSS,
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},
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{
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.value = SIGALG_RSA_PSS_RSAE_SHA512,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha512,
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.flags = SIGALG_FLAG_RSA_PSS,
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},
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{
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.value = SIGALG_RSA_PSS_PSS_SHA256,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha256,
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.flags = SIGALG_FLAG_RSA_PSS,
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},
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{
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.value = SIGALG_RSA_PSS_PSS_SHA384,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha384,
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.flags = SIGALG_FLAG_RSA_PSS,
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},
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{
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.value = SIGALG_RSA_PSS_PSS_SHA512,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha512,
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.flags = SIGALG_FLAG_RSA_PSS,
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},
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{
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.value = SIGALG_RSA_PKCS1_SHA224,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha224,
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},
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{
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.value = SIGALG_ECDSA_SECP224R1_SHA224,
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.key_type = EVP_PKEY_EC,
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.md = EVP_sha224,
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},
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{
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.value = SIGALG_RSA_PKCS1_SHA1,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_sha1,
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},
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{
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.value = SIGALG_ECDSA_SHA1,
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.key_type = EVP_PKEY_EC,
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.md = EVP_sha1,
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},
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{
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.value = SIGALG_RSA_PKCS1_MD5_SHA1,
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.key_type = EVP_PKEY_RSA,
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.md = EVP_md5_sha1,
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},
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{
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.value = SIGALG_NONE,
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},
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};
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/* Sigalgs for TLSv1.3, in preference order. */
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const uint16_t tls13_sigalgs[] = {
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SIGALG_RSA_PSS_RSAE_SHA512,
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SIGALG_RSA_PKCS1_SHA512,
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SIGALG_ECDSA_SECP521R1_SHA512,
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SIGALG_RSA_PSS_RSAE_SHA384,
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SIGALG_RSA_PKCS1_SHA384,
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SIGALG_ECDSA_SECP384R1_SHA384,
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SIGALG_RSA_PSS_RSAE_SHA256,
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SIGALG_RSA_PKCS1_SHA256,
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SIGALG_ECDSA_SECP256R1_SHA256,
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};
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const size_t tls13_sigalgs_len = (sizeof(tls13_sigalgs) / sizeof(tls13_sigalgs[0]));
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/* Sigalgs for TLSv1.2, in preference order. */
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const uint16_t tls12_sigalgs[] = {
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SIGALG_RSA_PSS_RSAE_SHA512,
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SIGALG_RSA_PKCS1_SHA512,
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SIGALG_ECDSA_SECP521R1_SHA512,
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SIGALG_RSA_PSS_RSAE_SHA384,
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SIGALG_RSA_PKCS1_SHA384,
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SIGALG_ECDSA_SECP384R1_SHA384,
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SIGALG_RSA_PSS_RSAE_SHA256,
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SIGALG_RSA_PKCS1_SHA256,
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SIGALG_ECDSA_SECP256R1_SHA256,
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SIGALG_RSA_PKCS1_SHA1, /* XXX */
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SIGALG_ECDSA_SHA1, /* XXX */
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};
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const size_t tls12_sigalgs_len = (sizeof(tls12_sigalgs) / sizeof(tls12_sigalgs[0]));
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static void
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ssl_sigalgs_for_version(uint16_t tls_version, const uint16_t **out_values,
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size_t *out_len)
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{
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if (tls_version >= TLS1_3_VERSION) {
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*out_values = tls13_sigalgs;
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*out_len = tls13_sigalgs_len;
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} else {
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*out_values = tls12_sigalgs;
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*out_len = tls12_sigalgs_len;
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}
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}
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static const struct ssl_sigalg *
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ssl_sigalg_lookup(uint16_t value)
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{
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int i;
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for (i = 0; sigalgs[i].value != SIGALG_NONE; i++) {
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if (sigalgs[i].value == value)
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return &sigalgs[i];
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}
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return NULL;
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}
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static const struct ssl_sigalg *
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ssl_sigalg_from_value(SSL *s, uint16_t value)
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{
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const uint16_t *values;
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size_t len;
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int i;
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ssl_sigalgs_for_version(s->s3->hs.negotiated_tls_version,
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&values, &len);
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for (i = 0; i < len; i++) {
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if (values[i] == value)
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return ssl_sigalg_lookup(value);
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}
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return NULL;
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}
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int
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ssl_sigalgs_build(uint16_t tls_version, CBB *cbb)
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{
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const uint16_t *values;
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size_t len;
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size_t i;
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ssl_sigalgs_for_version(tls_version, &values, &len);
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/* Add values in order as long as they are supported. */
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for (i = 0; i < len; i++) {
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/* Do not allow the legacy value for < 1.2 to be used. */
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if (values[i] == SIGALG_RSA_PKCS1_MD5_SHA1)
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return 0;
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if (ssl_sigalg_lookup(values[i]) == NULL)
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return 0;
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if (!CBB_add_u16(cbb, values[i]))
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return 0;
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}
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return 1;
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}
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static const struct ssl_sigalg *
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ssl_sigalg_for_legacy(SSL *s, EVP_PKEY *pkey)
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{
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/* Default signature algorithms used for TLSv1.2 and earlier. */
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switch (EVP_PKEY_id(pkey)) {
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case EVP_PKEY_RSA:
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if (s->s3->hs.negotiated_tls_version < TLS1_2_VERSION)
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return ssl_sigalg_lookup(SIGALG_RSA_PKCS1_MD5_SHA1);
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return ssl_sigalg_lookup(SIGALG_RSA_PKCS1_SHA1);
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case EVP_PKEY_EC:
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return ssl_sigalg_lookup(SIGALG_ECDSA_SHA1);
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#ifndef OPENSSL_NO_GOST
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case EVP_PKEY_GOSTR01:
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return ssl_sigalg_lookup(SIGALG_GOSTR01_GOST94);
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#endif
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}
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SSLerror(s, SSL_R_UNKNOWN_PKEY_TYPE);
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return NULL;
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}
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static int
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ssl_sigalg_pkey_ok(SSL *s, const struct ssl_sigalg *sigalg, EVP_PKEY *pkey)
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{
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if (sigalg == NULL || pkey == NULL)
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return 0;
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if (sigalg->key_type != EVP_PKEY_id(pkey))
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return 0;
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/* RSA PSS must have a sufficiently large RSA key. */
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if ((sigalg->flags & SIGALG_FLAG_RSA_PSS)) {
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if (EVP_PKEY_id(pkey) != EVP_PKEY_RSA ||
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EVP_PKEY_size(pkey) < (2 * EVP_MD_size(sigalg->md()) + 2))
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return 0;
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}
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if (s->s3->hs.negotiated_tls_version < TLS1_3_VERSION)
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return 1;
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/* RSA cannot be used without PSS in TLSv1.3. */
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if (sigalg->key_type == EVP_PKEY_RSA &&
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(sigalg->flags & SIGALG_FLAG_RSA_PSS) == 0)
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return 0;
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/* Ensure that curve matches for EC keys. */
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if (EVP_PKEY_id(pkey) == EVP_PKEY_EC) {
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if (sigalg->curve_nid == 0)
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return 0;
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if (EC_GROUP_get_curve_name(EC_KEY_get0_group(
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EVP_PKEY_get0_EC_KEY(pkey))) != sigalg->curve_nid)
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return 0;
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}
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return 1;
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}
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const struct ssl_sigalg *
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ssl_sigalg_select(SSL *s, EVP_PKEY *pkey)
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{
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CBS cbs;
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if (!SSL_USE_SIGALGS(s))
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return ssl_sigalg_for_legacy(s, pkey);
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/*
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* RFC 5246 allows a TLS 1.2 client to send no sigalgs extension,
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* in which case the server must use the default.
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*/
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if (s->s3->hs.negotiated_tls_version < TLS1_3_VERSION &&
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s->s3->hs.sigalgs == NULL)
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return ssl_sigalg_for_legacy(s, pkey);
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/*
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* If we get here, we have client or server sent sigalgs, use one.
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*/
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CBS_init(&cbs, s->s3->hs.sigalgs, s->s3->hs.sigalgs_len);
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while (CBS_len(&cbs) > 0) {
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const struct ssl_sigalg *sigalg;
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uint16_t sigalg_value;
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if (!CBS_get_u16(&cbs, &sigalg_value))
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return NULL;
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if ((sigalg = ssl_sigalg_from_value(s, sigalg_value)) == NULL)
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continue;
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if (ssl_sigalg_pkey_ok(s, sigalg, pkey))
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return sigalg;
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}
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SSLerror(s, SSL_R_UNKNOWN_PKEY_TYPE);
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return NULL;
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}
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const struct ssl_sigalg *
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ssl_sigalg_for_peer(SSL *s, EVP_PKEY *pkey, uint16_t sigalg_value)
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{
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const struct ssl_sigalg *sigalg;
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if (!SSL_USE_SIGALGS(s))
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return ssl_sigalg_for_legacy(s, pkey);
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if ((sigalg = ssl_sigalg_from_value(s, sigalg_value)) == NULL) {
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SSLerror(s, SSL_R_UNKNOWN_DIGEST);
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return NULL;
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}
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if (!ssl_sigalg_pkey_ok(s, sigalg, pkey)) {
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SSLerror(s, SSL_R_WRONG_SIGNATURE_TYPE);
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return NULL;
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}
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return sigalg;
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}
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