pineapple-src/externals/libressl/ssl/tls13_server.c

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2020-12-28 15:15:37 +00:00
/* $OpenBSD: tls13_server.c,v 1.61 2020/07/03 04:12:51 tb Exp $ */
/*
* Copyright (c) 2019, 2020 Joel Sing <jsing@openbsd.org>
* Copyright (c) 2020 Bob Beck <beck@openbsd.org>
*
* 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.
*/
#include <openssl/x509v3.h>
#include "ssl_locl.h"
#include "ssl_tlsext.h"
#include "tls13_handshake.h"
#include "tls13_internal.h"
int
tls13_server_init(struct tls13_ctx *ctx)
{
SSL *s = ctx->ssl;
if (!ssl_supported_version_range(s, &ctx->hs->min_version,
&ctx->hs->max_version)) {
SSLerror(s, SSL_R_NO_PROTOCOLS_AVAILABLE);
return 0;
}
s->version = ctx->hs->max_version;
tls13_record_layer_set_retry_after_phh(ctx->rl,
(s->internal->mode & SSL_MODE_AUTO_RETRY) != 0);
if (!ssl_get_new_session(s, 0)) /* XXX */
return 0;
tls13_record_layer_set_legacy_version(ctx->rl, TLS1_VERSION);
if (!tls1_transcript_init(s))
return 0;
arc4random_buf(s->s3->server_random, SSL3_RANDOM_SIZE);
return 1;
}
int
tls13_server_accept(struct tls13_ctx *ctx)
{
if (ctx->mode != TLS13_HS_SERVER)
return TLS13_IO_FAILURE;
return tls13_handshake_perform(ctx);
}
static int
tls13_client_hello_is_legacy(CBS *cbs)
{
CBS extensions_block, extensions, extension_data, versions;
uint16_t version, max_version = 0;
uint16_t type;
CBS_dup(cbs, &extensions_block);
if (!CBS_get_u16_length_prefixed(&extensions_block, &extensions))
return 1;
while (CBS_len(&extensions) > 0) {
if (!CBS_get_u16(&extensions, &type))
return 1;
if (!CBS_get_u16_length_prefixed(&extensions, &extension_data))
return 1;
if (type != TLSEXT_TYPE_supported_versions)
continue;
if (!CBS_get_u8_length_prefixed(&extension_data, &versions))
return 1;
while (CBS_len(&versions) > 0) {
if (!CBS_get_u16(&versions, &version))
return 1;
if (version >= max_version)
max_version = version;
}
if (CBS_len(&extension_data) != 0)
return 1;
}
return (max_version < TLS1_3_VERSION);
}
int
tls13_client_hello_required_extensions(struct tls13_ctx *ctx)
{
SSL *ssl = ctx->ssl;
/*
* RFC 8446, section 9.2. If the ClientHello has supported_versions
* containing TLSv1.3, presence or absence of some extensions requires
* presence or absence of others.
*/
/*
* If we got no pre_shared_key, then signature_algorithms and
* supported_groups must both be present.
*/
if (!tlsext_extension_seen(ssl, TLSEXT_TYPE_pre_shared_key)) {
if (!tlsext_extension_seen(ssl, TLSEXT_TYPE_signature_algorithms))
return 0;
if (!tlsext_extension_seen(ssl, TLSEXT_TYPE_supported_groups))
return 0;
}
/*
* supported_groups and key_share must either both be present or
* both be absent.
*/
if (tlsext_extension_seen(ssl, TLSEXT_TYPE_supported_groups) !=
tlsext_extension_seen(ssl, TLSEXT_TYPE_key_share))
return 0;
/*
* XXX - Require server_name from client? If so, we SHOULD enforce
* this here - RFC 8446, 9.2.
*/
return 1;
}
static const uint8_t tls13_compression_null_only[] = { 0 };
static int
tls13_client_hello_process(struct tls13_ctx *ctx, CBS *cbs)
{
CBS cipher_suites, client_random, compression_methods, session_id;
STACK_OF(SSL_CIPHER) *ciphers = NULL;
const SSL_CIPHER *cipher;
uint16_t legacy_version;
int alert_desc;
SSL *s = ctx->ssl;
int ret = 0;
if (!CBS_get_u16(cbs, &legacy_version))
goto err;
if (!CBS_get_bytes(cbs, &client_random, SSL3_RANDOM_SIZE))
goto err;
if (!CBS_get_u8_length_prefixed(cbs, &session_id))
goto err;
if (!CBS_get_u16_length_prefixed(cbs, &cipher_suites))
goto err;
if (!CBS_get_u8_length_prefixed(cbs, &compression_methods))
goto err;
if (tls13_client_hello_is_legacy(cbs) || s->version < TLS1_3_VERSION) {
if (!CBS_skip(cbs, CBS_len(cbs)))
goto err;
return tls13_use_legacy_server(ctx);
}
/* Add decoded values to the current ClientHello hash */
if (!tls13_clienthello_hash_init(ctx)) {
ctx->alert = TLS13_ALERT_INTERNAL_ERROR;
goto err;
}
if (!tls13_clienthello_hash_update_bytes(ctx, (void *)&legacy_version,
sizeof(legacy_version))) {
ctx->alert = TLS13_ALERT_INTERNAL_ERROR;
goto err;
}
if (!tls13_clienthello_hash_update(ctx, &client_random)) {
ctx->alert = TLS13_ALERT_INTERNAL_ERROR;
goto err;
}
if (!tls13_clienthello_hash_update(ctx, &session_id)) {
ctx->alert = TLS13_ALERT_INTERNAL_ERROR;
goto err;
}
if (!tls13_clienthello_hash_update(ctx, &cipher_suites)) {
ctx->alert = TLS13_ALERT_INTERNAL_ERROR;
goto err;
}
if (!tls13_clienthello_hash_update(ctx, &compression_methods)) {
ctx->alert = TLS13_ALERT_INTERNAL_ERROR;
goto err;
}
if (!tlsext_server_parse(s, SSL_TLSEXT_MSG_CH, cbs, &alert_desc)) {
ctx->alert = alert_desc;
goto err;
}
/* Finalize first ClientHello hash, or validate against it */
if (!ctx->hs->hrr) {
if (!tls13_clienthello_hash_finalize(ctx)) {
ctx->alert = TLS13_ALERT_INTERNAL_ERROR;
goto err;
}
} else {
if (!tls13_clienthello_hash_validate(ctx)) {
ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER;
goto err;
}
tls13_clienthello_hash_clear(ctx->hs);
}
if (!tls13_client_hello_required_extensions(ctx)) {
ctx->alert = TLS13_ALERT_MISSING_EXTENSION;
goto err;
}
/*
* If we got this far we have a supported versions extension that offers
* TLS 1.3 or later. This requires the legacy version be set to 0x0303.
*/
if (legacy_version != TLS1_2_VERSION) {
ctx->alert = TLS13_ALERT_PROTOCOL_VERSION;
goto err;
}
/* Store legacy session identifier so we can echo it. */
if (CBS_len(&session_id) > sizeof(ctx->hs->legacy_session_id)) {
ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER;
goto err;
}
if (!CBS_write_bytes(&session_id, ctx->hs->legacy_session_id,
sizeof(ctx->hs->legacy_session_id),
&ctx->hs->legacy_session_id_len)) {
ctx->alert = TLS13_ALERT_INTERNAL_ERROR;
goto err;
}
/* Parse cipher suites list and select preferred cipher. */
if ((ciphers = ssl_bytes_to_cipher_list(s, &cipher_suites)) == NULL) {
ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER;
goto err;
}
cipher = ssl3_choose_cipher(s, ciphers, SSL_get_ciphers(s));
if (cipher == NULL) {
tls13_set_errorx(ctx, TLS13_ERR_NO_SHARED_CIPHER, 0,
"no shared cipher found", NULL);
ctx->alert = TLS13_ALERT_HANDSHAKE_FAILURE;
goto err;
}
S3I(s)->hs.new_cipher = cipher;
/* Ensure only the NULL compression method is advertised. */
if (!CBS_mem_equal(&compression_methods, tls13_compression_null_only,
sizeof(tls13_compression_null_only))) {
ctx->alert = TLS13_ALERT_ILLEGAL_PARAMETER;
goto err;
}
ret = 1;
err:
sk_SSL_CIPHER_free(ciphers);
return ret;
}
int
tls13_client_hello_recv(struct tls13_ctx *ctx, CBS *cbs)
{
SSL *s = ctx->ssl;
if (!tls13_client_hello_process(ctx, cbs))
goto err;
/* See if we switched back to the legacy client method. */
if (s->method->internal->version < TLS1_3_VERSION)
return 1;
tls13_record_layer_set_legacy_version(ctx->rl, TLS1_2_VERSION);
/*
* If a matching key share was provided, we do not need to send a
* HelloRetryRequest.
*/
/*
* XXX - ideally NEGOTIATED would only be added after record protection
* has been enabled. This would probably mean using either an
* INITIAL | WITHOUT_HRR state, or another intermediate state.
*/
if (ctx->hs->key_share != NULL)
ctx->handshake_stage.hs_type |= NEGOTIATED | WITHOUT_HRR;
/* XXX - check this is the correct point */
tls13_record_layer_allow_ccs(ctx->rl, 1);
return 1;
err:
return 0;
}
static int
tls13_server_hello_build(struct tls13_ctx *ctx, CBB *cbb, int hrr)
{
uint16_t tlsext_msg_type = SSL_TLSEXT_MSG_SH;
const uint8_t *server_random;
CBB session_id;
SSL *s = ctx->ssl;
uint16_t cipher;
cipher = SSL_CIPHER_get_value(S3I(s)->hs.new_cipher);
server_random = s->s3->server_random;
if (hrr) {
server_random = tls13_hello_retry_request_hash;
tlsext_msg_type = SSL_TLSEXT_MSG_HRR;
}
if (!CBB_add_u16(cbb, TLS1_2_VERSION))
goto err;
if (!CBB_add_bytes(cbb, server_random, SSL3_RANDOM_SIZE))
goto err;
if (!CBB_add_u8_length_prefixed(cbb, &session_id))
goto err;
if (!CBB_add_bytes(&session_id, ctx->hs->legacy_session_id,
ctx->hs->legacy_session_id_len))
goto err;
if (!CBB_add_u16(cbb, cipher))
goto err;
if (!CBB_add_u8(cbb, 0))
goto err;
if (!tlsext_server_build(s, tlsext_msg_type, cbb))
goto err;
if (!CBB_flush(cbb))
goto err;
return 1;
err:
return 0;
}
static int
tls13_server_engage_record_protection(struct tls13_ctx *ctx)
{
struct tls13_secrets *secrets;
struct tls13_secret context;
unsigned char buf[EVP_MAX_MD_SIZE];
uint8_t *shared_key = NULL;
size_t shared_key_len = 0;
size_t hash_len;
SSL *s = ctx->ssl;
int ret = 0;
if (!tls13_key_share_derive(ctx->hs->key_share,
&shared_key, &shared_key_len))
goto err;
s->session->cipher = S3I(s)->hs.new_cipher;
if ((ctx->aead = tls13_cipher_aead(S3I(s)->hs.new_cipher)) == NULL)
goto err;
if ((ctx->hash = tls13_cipher_hash(S3I(s)->hs.new_cipher)) == NULL)
goto err;
if ((secrets = tls13_secrets_create(ctx->hash, 0)) == NULL)
goto err;
ctx->hs->secrets = secrets;
/* XXX - pass in hash. */
if (!tls1_transcript_hash_init(s))
goto err;
tls1_transcript_free(s);
if (!tls1_transcript_hash_value(s, buf, sizeof(buf), &hash_len))
goto err;
context.data = buf;
context.len = hash_len;
/* Early secrets. */
if (!tls13_derive_early_secrets(secrets, secrets->zeros.data,
secrets->zeros.len, &context))
goto err;
/* Handshake secrets. */
if (!tls13_derive_handshake_secrets(ctx->hs->secrets, shared_key,
shared_key_len, &context))
goto err;
tls13_record_layer_set_aead(ctx->rl, ctx->aead);
tls13_record_layer_set_hash(ctx->rl, ctx->hash);
if (!tls13_record_layer_set_read_traffic_key(ctx->rl,
&secrets->client_handshake_traffic))
goto err;
if (!tls13_record_layer_set_write_traffic_key(ctx->rl,
&secrets->server_handshake_traffic))
goto err;
ctx->handshake_stage.hs_type |= NEGOTIATED;
if (!(SSL_get_verify_mode(s) & SSL_VERIFY_PEER))
ctx->handshake_stage.hs_type |= WITHOUT_CR;
ret = 1;
err:
freezero(shared_key, shared_key_len);
return ret;
}
int
tls13_server_hello_retry_request_send(struct tls13_ctx *ctx, CBB *cbb)
{
int nid;
ctx->hs->hrr = 1;
if (!tls13_synthetic_handshake_message(ctx))
return 0;
if (ctx->hs->key_share != NULL)
return 0;
if ((nid = tls1_get_shared_curve(ctx->ssl)) == NID_undef)
return 0;
if ((ctx->hs->server_group = tls1_ec_nid2curve_id(nid)) == 0)
return 0;
if (!tls13_server_hello_build(ctx, cbb, 1))
return 0;
return 1;
}
int
tls13_server_hello_retry_request_sent(struct tls13_ctx *ctx)
{
/*
* If the client has requested middlebox compatibility mode,
* we MUST send a dummy CCS following our first handshake message.
* See RFC 8446 Appendix D.4.
*/
if (ctx->hs->legacy_session_id_len > 0)
ctx->send_dummy_ccs_after = 1;
return 1;
}
int
tls13_client_hello_retry_recv(struct tls13_ctx *ctx, CBS *cbs)
{
SSL *s = ctx->ssl;
if (!tls13_client_hello_process(ctx, cbs))
return 0;
/* XXX - need further checks. */
if (s->method->internal->version < TLS1_3_VERSION)
return 0;
ctx->hs->hrr = 0;
return 1;
}
static int
tls13_servername_process(struct tls13_ctx *ctx)
{
uint8_t alert = TLS13_ALERT_INTERNAL_ERROR;
if (!tls13_legacy_servername_process(ctx, &alert)) {
ctx->alert = alert;
return 0;
}
return 1;
}
int
tls13_server_hello_send(struct tls13_ctx *ctx, CBB *cbb)
{
if (ctx->hs->key_share == NULL)
return 0;
if (!tls13_key_share_generate(ctx->hs->key_share))
return 0;
if (!tls13_servername_process(ctx))
return 0;
ctx->hs->server_group = 0;
if (!tls13_server_hello_build(ctx, cbb, 0))
return 0;
return 1;
}
int
tls13_server_hello_sent(struct tls13_ctx *ctx)
{
/*
* If the client has requested middlebox compatibility mode,
* we MUST send a dummy CCS following our first handshake message.
* See RFC 8446 Appendix D.4.
*/
if ((ctx->handshake_stage.hs_type & WITHOUT_HRR) &&
ctx->hs->legacy_session_id_len > 0)
ctx->send_dummy_ccs_after = 1;
return tls13_server_engage_record_protection(ctx);
}
int
tls13_server_encrypted_extensions_send(struct tls13_ctx *ctx, CBB *cbb)
{
if (!tlsext_server_build(ctx->ssl, SSL_TLSEXT_MSG_EE, cbb))
goto err;
return 1;
err:
return 0;
}
int
tls13_server_certificate_request_send(struct tls13_ctx *ctx, CBB *cbb)
{
CBB certificate_request_context;
if (!CBB_add_u8_length_prefixed(cbb, &certificate_request_context))
goto err;
if (!tlsext_server_build(ctx->ssl, SSL_TLSEXT_MSG_CR, cbb))
goto err;
if (!CBB_flush(cbb))
goto err;
return 1;
err:
return 0;
}
static int
tls13_server_check_certificate(struct tls13_ctx *ctx, CERT_PKEY *cpk,
int *ok, const struct ssl_sigalg **out_sigalg)
{
const struct ssl_sigalg *sigalg;
SSL *s = ctx->ssl;
*ok = 0;
*out_sigalg = NULL;
if (cpk->x509 == NULL || cpk->privatekey == NULL)
goto done;
if (!X509_check_purpose(cpk->x509, -1, 0))
return 0;
/*
* The digitalSignature bit MUST be set if the Key Usage extension is
* present as per RFC 8446 section 4.4.2.2.
*/
if ((cpk->x509->ex_flags & EXFLAG_KUSAGE) &&
!(cpk->x509->ex_kusage & X509v3_KU_DIGITAL_SIGNATURE))
goto done;
if ((sigalg = ssl_sigalg_select(s, cpk->privatekey)) == NULL)
goto done;
*ok = 1;
*out_sigalg = sigalg;
done:
return 1;
}
static int
tls13_server_select_certificate(struct tls13_ctx *ctx, CERT_PKEY **out_cpk,
const struct ssl_sigalg **out_sigalg)
{
SSL *s = ctx->ssl;
const struct ssl_sigalg *sigalg;
CERT_PKEY *cpk;
int cert_ok;
*out_cpk = NULL;
*out_sigalg = NULL;
cpk = &s->cert->pkeys[SSL_PKEY_ECC];
if (!tls13_server_check_certificate(ctx, cpk, &cert_ok, &sigalg))
return 0;
if (cert_ok)
goto done;
cpk = &s->cert->pkeys[SSL_PKEY_RSA];
if (!tls13_server_check_certificate(ctx, cpk, &cert_ok, &sigalg))
return 0;
if (cert_ok)
goto done;
cpk = NULL;
sigalg = NULL;
done:
*out_cpk = cpk;
*out_sigalg = sigalg;
return 1;
}
int
tls13_server_certificate_send(struct tls13_ctx *ctx, CBB *cbb)
{
SSL *s = ctx->ssl;
CBB cert_request_context, cert_list;
const struct ssl_sigalg *sigalg;
STACK_OF(X509) *chain;
CERT_PKEY *cpk;
X509 *cert;
int i, ret = 0;
if (!tls13_server_select_certificate(ctx, &cpk, &sigalg))
goto err;
if (cpk == NULL) {
/* A server must always provide a certificate. */
ctx->alert = TLS13_ALERT_HANDSHAKE_FAILURE;
tls13_set_errorx(ctx, TLS13_ERR_NO_CERTIFICATE, 0,
"no server certificate", NULL);
goto err;
}
ctx->hs->cpk = cpk;
ctx->hs->sigalg = sigalg;
if ((chain = cpk->chain) == NULL)
chain = s->ctx->extra_certs;
if (!CBB_add_u8_length_prefixed(cbb, &cert_request_context))
goto err;
if (!CBB_add_u24_length_prefixed(cbb, &cert_list))
goto err;
if (!tls13_cert_add(ctx, &cert_list, cpk->x509, tlsext_server_build))
goto err;
for (i = 0; i < sk_X509_num(chain); i++) {
cert = sk_X509_value(chain, i);
/*
* XXX we don't send extensions with chain certs to avoid sending
* a leaf ocsp stape with the chain certs. This needs to get
* fixed
*/
if (!tls13_cert_add(ctx, &cert_list, cert, NULL))
goto err;
}
if (!CBB_flush(cbb))
goto err;
ret = 1;
err:
return ret;
}
int
tls13_server_certificate_verify_send(struct tls13_ctx *ctx, CBB *cbb)
{
const struct ssl_sigalg *sigalg;
uint8_t *sig = NULL, *sig_content = NULL;
size_t sig_len, sig_content_len;
EVP_MD_CTX *mdctx = NULL;
EVP_PKEY_CTX *pctx;
EVP_PKEY *pkey;
const CERT_PKEY *cpk;
CBB sig_cbb;
int ret = 0;
memset(&sig_cbb, 0, sizeof(sig_cbb));
if ((cpk = ctx->hs->cpk) == NULL)
goto err;
if ((sigalg = ctx->hs->sigalg) == NULL)
goto err;
pkey = cpk->privatekey;
if (!CBB_init(&sig_cbb, 0))
goto err;
if (!CBB_add_bytes(&sig_cbb, tls13_cert_verify_pad,
sizeof(tls13_cert_verify_pad)))
goto err;
if (!CBB_add_bytes(&sig_cbb, tls13_cert_server_verify_context,
strlen(tls13_cert_server_verify_context)))
goto err;
if (!CBB_add_u8(&sig_cbb, 0))
goto err;
if (!CBB_add_bytes(&sig_cbb, ctx->hs->transcript_hash,
ctx->hs->transcript_hash_len))
goto err;
if (!CBB_finish(&sig_cbb, &sig_content, &sig_content_len))
goto err;
if ((mdctx = EVP_MD_CTX_new()) == NULL)
goto err;
if (!EVP_DigestSignInit(mdctx, &pctx, sigalg->md(), NULL, pkey))
goto err;
if (sigalg->flags & SIGALG_FLAG_RSA_PSS) {
if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING))
goto err;
if (!EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1))
goto err;
}
if (!EVP_DigestSignUpdate(mdctx, sig_content, sig_content_len))
goto err;
if (EVP_DigestSignFinal(mdctx, NULL, &sig_len) <= 0)
goto err;
if ((sig = calloc(1, sig_len)) == NULL)
goto err;
if (EVP_DigestSignFinal(mdctx, sig, &sig_len) <= 0)
goto err;
if (!CBB_add_u16(cbb, sigalg->value))
goto err;
if (!CBB_add_u16_length_prefixed(cbb, &sig_cbb))
goto err;
if (!CBB_add_bytes(&sig_cbb, sig, sig_len))
goto err;
if (!CBB_flush(cbb))
goto err;
ret = 1;
err:
if (!ret && ctx->alert == 0)
ctx->alert = TLS13_ALERT_INTERNAL_ERROR;
CBB_cleanup(&sig_cbb);
EVP_MD_CTX_free(mdctx);
free(sig_content);
free(sig);
return ret;
}
int
tls13_server_finished_send(struct tls13_ctx *ctx, CBB *cbb)
{
struct tls13_secrets *secrets = ctx->hs->secrets;
struct tls13_secret context = { .data = "", .len = 0 };
struct tls13_secret finished_key;
uint8_t transcript_hash[EVP_MAX_MD_SIZE];
size_t transcript_hash_len;
uint8_t key[EVP_MAX_MD_SIZE];
uint8_t *verify_data;
size_t hmac_len;
unsigned int hlen;
HMAC_CTX *hmac_ctx = NULL;
int ret = 0;
finished_key.data = key;
finished_key.len = EVP_MD_size(ctx->hash);
if (!tls13_hkdf_expand_label(&finished_key, ctx->hash,
&secrets->server_handshake_traffic, "finished",
&context))
goto err;
if (!tls1_transcript_hash_value(ctx->ssl, transcript_hash,
sizeof(transcript_hash), &transcript_hash_len))
goto err;
if ((hmac_ctx = HMAC_CTX_new()) == NULL)
goto err;
if (!HMAC_Init_ex(hmac_ctx, finished_key.data, finished_key.len,
ctx->hash, NULL))
goto err;
if (!HMAC_Update(hmac_ctx, transcript_hash, transcript_hash_len))
goto err;
hmac_len = HMAC_size(hmac_ctx);
if (!CBB_add_space(cbb, &verify_data, hmac_len))
goto err;
if (!HMAC_Final(hmac_ctx, verify_data, &hlen))
goto err;
if (hlen != hmac_len)
goto err;
ret = 1;
err:
HMAC_CTX_free(hmac_ctx);
return ret;
}
int
tls13_server_finished_sent(struct tls13_ctx *ctx)
{
struct tls13_secrets *secrets = ctx->hs->secrets;
struct tls13_secret context = { .data = "", .len = 0 };
/*
* Derive application traffic keys.
*/
context.data = ctx->hs->transcript_hash;
context.len = ctx->hs->transcript_hash_len;
if (!tls13_derive_application_secrets(secrets, &context))
return 0;
/*
* Any records following the server finished message must be encrypted
* using the server application traffic keys.
*/
return tls13_record_layer_set_write_traffic_key(ctx->rl,
&secrets->server_application_traffic);
}
int
tls13_client_certificate_recv(struct tls13_ctx *ctx, CBS *cbs)
{
CBS cert_request_context, cert_list, cert_data, cert_exts;
struct stack_st_X509 *certs = NULL;
SSL *s = ctx->ssl;
X509 *cert = NULL;
EVP_PKEY *pkey;
const uint8_t *p;
int cert_idx;
int ret = 0;
if (!CBS_get_u8_length_prefixed(cbs, &cert_request_context))
goto err;
if (CBS_len(&cert_request_context) != 0)
goto err;
if (!CBS_get_u24_length_prefixed(cbs, &cert_list))
goto err;
if (CBS_len(&cert_list) == 0) {
if (!(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT))
return 1;
ctx->alert = TLS13_ALERT_CERTIFICATE_REQUIRED;
tls13_set_errorx(ctx, TLS13_ERR_NO_PEER_CERTIFICATE, 0,
"peer did not provide a certificate", NULL);
goto err;
}
if ((certs = sk_X509_new_null()) == NULL)
goto err;
while (CBS_len(&cert_list) > 0) {
if (!CBS_get_u24_length_prefixed(&cert_list, &cert_data))
goto err;
if (!CBS_get_u16_length_prefixed(&cert_list, &cert_exts))
goto err;
p = CBS_data(&cert_data);
if ((cert = d2i_X509(NULL, &p, CBS_len(&cert_data))) == NULL)
goto err;
if (p != CBS_data(&cert_data) + CBS_len(&cert_data))
goto err;
if (!sk_X509_push(certs, cert))
goto err;
cert = NULL;
}
/*
* At this stage we still have no proof of possession. As such, it would
* be preferable to keep the chain and verify once we have successfully
* processed the CertificateVerify message.
*/
if (ssl_verify_cert_chain(s, certs) <= 0) {
ctx->alert = ssl_verify_alarm_type(s->verify_result);
tls13_set_errorx(ctx, TLS13_ERR_VERIFY_FAILED, 0,
"failed to verify peer certificate", NULL);
goto err;
}
ERR_clear_error();
cert = sk_X509_value(certs, 0);
X509_up_ref(cert);
if ((pkey = X509_get0_pubkey(cert)) == NULL)
goto err;
if (EVP_PKEY_missing_parameters(pkey))
goto err;
if ((cert_idx = ssl_cert_type(cert, pkey)) < 0)
goto err;
ssl_sess_cert_free(SSI(s)->sess_cert);
if ((SSI(s)->sess_cert = ssl_sess_cert_new()) == NULL)
goto err;
SSI(s)->sess_cert->cert_chain = certs;
certs = NULL;
X509_up_ref(cert);
SSI(s)->sess_cert->peer_pkeys[cert_idx].x509 = cert;
SSI(s)->sess_cert->peer_key = &(SSI(s)->sess_cert->peer_pkeys[cert_idx]);
X509_free(s->session->peer);
X509_up_ref(cert);
s->session->peer = cert;
s->session->verify_result = s->verify_result;
ctx->handshake_stage.hs_type |= WITH_CCV;
ret = 1;
err:
sk_X509_pop_free(certs, X509_free);
X509_free(cert);
return ret;
}
int
tls13_client_certificate_verify_recv(struct tls13_ctx *ctx, CBS *cbs)
{
const struct ssl_sigalg *sigalg;
uint16_t signature_scheme;
uint8_t *sig_content = NULL;
size_t sig_content_len;
EVP_MD_CTX *mdctx = NULL;
EVP_PKEY_CTX *pctx;
EVP_PKEY *pkey;
X509 *cert;
CBS signature;
CBB cbb;
int ret = 0;
memset(&cbb, 0, sizeof(cbb));
if (!CBS_get_u16(cbs, &signature_scheme))
goto err;
if (!CBS_get_u16_length_prefixed(cbs, &signature))
goto err;
if ((sigalg = ssl_sigalg(signature_scheme, tls13_sigalgs,
tls13_sigalgs_len)) == NULL)
goto err;
if (!CBB_init(&cbb, 0))
goto err;
if (!CBB_add_bytes(&cbb, tls13_cert_verify_pad,
sizeof(tls13_cert_verify_pad)))
goto err;
if (!CBB_add_bytes(&cbb, tls13_cert_client_verify_context,
strlen(tls13_cert_client_verify_context)))
goto err;
if (!CBB_add_u8(&cbb, 0))
goto err;
if (!CBB_add_bytes(&cbb, ctx->hs->transcript_hash,
ctx->hs->transcript_hash_len))
goto err;
if (!CBB_finish(&cbb, &sig_content, &sig_content_len))
goto err;
if ((cert = ctx->ssl->session->peer) == NULL)
goto err;
if ((pkey = X509_get0_pubkey(cert)) == NULL)
goto err;
if (!ssl_sigalg_pkey_ok(sigalg, pkey, 1))
goto err;
if (CBS_len(&signature) > EVP_PKEY_size(pkey))
goto err;
if ((mdctx = EVP_MD_CTX_new()) == NULL)
goto err;
if (!EVP_DigestVerifyInit(mdctx, &pctx, sigalg->md(), NULL, pkey))
goto err;
if (sigalg->flags & SIGALG_FLAG_RSA_PSS) {
if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING))
goto err;
if (!EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1))
goto err;
}
if (!EVP_DigestVerifyUpdate(mdctx, sig_content, sig_content_len)) {
ctx->alert = TLS13_ALERT_DECRYPT_ERROR;
goto err;
}
if (EVP_DigestVerifyFinal(mdctx, CBS_data(&signature),
CBS_len(&signature)) <= 0) {
ctx->alert = TLS13_ALERT_DECRYPT_ERROR;
goto err;
}
ret = 1;
err:
if (!ret && ctx->alert == 0)
ctx->alert = TLS13_ALERT_DECODE_ERROR;
CBB_cleanup(&cbb);
EVP_MD_CTX_free(mdctx);
free(sig_content);
return ret;
}
int
tls13_client_end_of_early_data_recv(struct tls13_ctx *ctx, CBS *cbs)
{
return 0;
}
int
tls13_client_finished_recv(struct tls13_ctx *ctx, CBS *cbs)
{
struct tls13_secrets *secrets = ctx->hs->secrets;
struct tls13_secret context = { .data = "", .len = 0 };
struct tls13_secret finished_key;
uint8_t *verify_data = NULL;
size_t verify_data_len;
uint8_t key[EVP_MAX_MD_SIZE];
HMAC_CTX *hmac_ctx = NULL;
unsigned int hlen;
int ret = 0;
/*
* Verify client finished.
*/
finished_key.data = key;
finished_key.len = EVP_MD_size(ctx->hash);
if (!tls13_hkdf_expand_label(&finished_key, ctx->hash,
&secrets->client_handshake_traffic, "finished",
&context))
goto err;
if ((hmac_ctx = HMAC_CTX_new()) == NULL)
goto err;
if (!HMAC_Init_ex(hmac_ctx, finished_key.data, finished_key.len,
ctx->hash, NULL))
goto err;
if (!HMAC_Update(hmac_ctx, ctx->hs->transcript_hash,
ctx->hs->transcript_hash_len))
goto err;
verify_data_len = HMAC_size(hmac_ctx);
if ((verify_data = calloc(1, verify_data_len)) == NULL)
goto err;
if (!HMAC_Final(hmac_ctx, verify_data, &hlen))
goto err;
if (hlen != verify_data_len)
goto err;
if (!CBS_mem_equal(cbs, verify_data, verify_data_len)) {
ctx->alert = TLS13_ALERT_DECRYPT_ERROR;
goto err;
}
if (!CBS_skip(cbs, verify_data_len))
goto err;
/*
* Any records following the client finished message must be encrypted
* using the client application traffic keys.
*/
if (!tls13_record_layer_set_read_traffic_key(ctx->rl,
&secrets->client_application_traffic))
goto err;
tls13_record_layer_allow_ccs(ctx->rl, 0);
ret = 1;
err:
HMAC_CTX_free(hmac_ctx);
free(verify_data);
return ret;
}