pineapple/externals/libressl/ssl/tls13_lib.c
2022-04-24 22:29:35 +02:00

644 lines
15 KiB
C
Executable file

/* $OpenBSD: tls13_lib.c,v 1.63 2022/02/05 14:54:10 jsing Exp $ */
/*
* Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
* Copyright (c) 2019 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 <stddef.h>
#include <openssl/evp.h>
#include "ssl_locl.h"
#include "ssl_tlsext.h"
#include "tls13_internal.h"
/*
* Downgrade sentinels - RFC 8446 section 4.1.3, magic values which must be set
* by the server in server random if it is willing to downgrade but supports
* TLSv1.3
*/
const uint8_t tls13_downgrade_12[8] = {
0x44, 0x4f, 0x57, 0x4e, 0x47, 0x52, 0x44, 0x01,
};
const uint8_t tls13_downgrade_11[8] = {
0x44, 0x4f, 0x57, 0x4e, 0x47, 0x52, 0x44, 0x00,
};
/*
* HelloRetryRequest hash - RFC 8446 section 4.1.3.
*/
const uint8_t tls13_hello_retry_request_hash[32] = {
0xcf, 0x21, 0xad, 0x74, 0xe5, 0x9a, 0x61, 0x11,
0xbe, 0x1d, 0x8c, 0x02, 0x1e, 0x65, 0xb8, 0x91,
0xc2, 0xa2, 0x11, 0x16, 0x7a, 0xbb, 0x8c, 0x5e,
0x07, 0x9e, 0x09, 0xe2, 0xc8, 0xa8, 0x33, 0x9c,
};
/*
* Certificate Verify padding - RFC 8446 section 4.4.3.
*/
const uint8_t tls13_cert_verify_pad[64] = {
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
};
const uint8_t tls13_cert_client_verify_context[] =
"TLS 1.3, client CertificateVerify";
const uint8_t tls13_cert_server_verify_context[] =
"TLS 1.3, server CertificateVerify";
const EVP_AEAD *
tls13_cipher_aead(const SSL_CIPHER *cipher)
{
if (cipher == NULL)
return NULL;
if (cipher->algorithm_ssl != SSL_TLSV1_3)
return NULL;
switch (cipher->algorithm_enc) {
case SSL_AES128GCM:
return EVP_aead_aes_128_gcm();
case SSL_AES256GCM:
return EVP_aead_aes_256_gcm();
case SSL_CHACHA20POLY1305:
return EVP_aead_chacha20_poly1305();
}
return NULL;
}
const EVP_MD *
tls13_cipher_hash(const SSL_CIPHER *cipher)
{
if (cipher == NULL)
return NULL;
if (cipher->algorithm_ssl != SSL_TLSV1_3)
return NULL;
switch (cipher->algorithm2) {
case SSL_HANDSHAKE_MAC_SHA256:
return EVP_sha256();
case SSL_HANDSHAKE_MAC_SHA384:
return EVP_sha384();
}
return NULL;
}
static void
tls13_alert_received_cb(uint8_t alert_desc, void *arg)
{
struct tls13_ctx *ctx = arg;
if (alert_desc == TLS13_ALERT_CLOSE_NOTIFY) {
ctx->close_notify_recv = 1;
ctx->ssl->internal->shutdown |= SSL_RECEIVED_SHUTDOWN;
ctx->ssl->s3->warn_alert = alert_desc;
return;
}
if (alert_desc == TLS13_ALERT_USER_CANCELED) {
/*
* We treat this as advisory, since a close_notify alert
* SHOULD follow this alert (RFC 8446 section 6.1).
*/
return;
}
/* All other alerts are treated as fatal in TLSv1.3. */
ctx->ssl->s3->fatal_alert = alert_desc;
SSLerror(ctx->ssl, SSL_AD_REASON_OFFSET + alert_desc);
ERR_asprintf_error_data("SSL alert number %d", alert_desc);
SSL_CTX_remove_session(ctx->ssl->ctx, ctx->ssl->session);
}
static void
tls13_alert_sent_cb(uint8_t alert_desc, void *arg)
{
struct tls13_ctx *ctx = arg;
if (alert_desc == TLS13_ALERT_CLOSE_NOTIFY) {
ctx->close_notify_sent = 1;
return;
}
if (alert_desc == TLS13_ALERT_USER_CANCELED) {
return;
}
/* All other alerts are treated as fatal in TLSv1.3. */
if (ctx->error.code == 0)
SSLerror(ctx->ssl, SSL_AD_REASON_OFFSET + alert_desc);
}
static void
tls13_legacy_handshake_message_recv_cb(void *arg)
{
struct tls13_ctx *ctx = arg;
SSL *s = ctx->ssl;
CBS cbs;
if (s->internal->msg_callback == NULL)
return;
tls13_handshake_msg_data(ctx->hs_msg, &cbs);
ssl_msg_callback(s, 0, SSL3_RT_HANDSHAKE, CBS_data(&cbs), CBS_len(&cbs));
}
static void
tls13_legacy_handshake_message_sent_cb(void *arg)
{
struct tls13_ctx *ctx = arg;
SSL *s = ctx->ssl;
CBS cbs;
if (s->internal->msg_callback == NULL)
return;
tls13_handshake_msg_data(ctx->hs_msg, &cbs);
ssl_msg_callback(s, 1, SSL3_RT_HANDSHAKE, CBS_data(&cbs), CBS_len(&cbs));
}
static void
tls13_legacy_info_cb(void *arg, int state, int ret)
{
struct tls13_ctx *ctx = arg;
SSL *s = ctx->ssl;
ssl_info_callback(s, state, ret);
}
static int
tls13_legacy_ocsp_status_recv_cb(void *arg)
{
struct tls13_ctx *ctx = arg;
SSL *s = ctx->ssl;
int ret;
if (s->ctx->internal->tlsext_status_cb == NULL)
return 1;
ret = s->ctx->internal->tlsext_status_cb(s,
s->ctx->internal->tlsext_status_arg);
if (ret < 0) {
ctx->alert = TLS13_ALERT_INTERNAL_ERROR;
SSLerror(s, ERR_R_MALLOC_FAILURE);
return 0;
}
if (ret == 0) {
ctx->alert = TLS13_ALERT_BAD_CERTIFICATE_STATUS_RESPONSE;
SSLerror(s, SSL_R_INVALID_STATUS_RESPONSE);
return 0;
}
return 1;
}
static int
tls13_phh_update_local_traffic_secret(struct tls13_ctx *ctx)
{
struct tls13_secrets *secrets = ctx->hs->tls13.secrets;
if (ctx->mode == TLS13_HS_CLIENT)
return (tls13_update_client_traffic_secret(secrets) &&
tls13_record_layer_set_write_traffic_key(ctx->rl,
&secrets->client_application_traffic));
return (tls13_update_server_traffic_secret(secrets) &&
tls13_record_layer_set_read_traffic_key(ctx->rl,
&secrets->server_application_traffic));
}
static int
tls13_phh_update_peer_traffic_secret(struct tls13_ctx *ctx)
{
struct tls13_secrets *secrets = ctx->hs->tls13.secrets;
if (ctx->mode == TLS13_HS_CLIENT)
return (tls13_update_server_traffic_secret(secrets) &&
tls13_record_layer_set_read_traffic_key(ctx->rl,
&secrets->server_application_traffic));
return (tls13_update_client_traffic_secret(secrets) &&
tls13_record_layer_set_write_traffic_key(ctx->rl,
&secrets->client_application_traffic));
}
/*
* XXX arbitrarily chosen limit of 100 post handshake handshake
* messages in an hour - to avoid a hostile peer from constantly
* requesting certificates or key renegotiaitons, etc.
*/
static int
tls13_phh_limit_check(struct tls13_ctx *ctx)
{
time_t now = time(NULL);
if (ctx->phh_last_seen > now - TLS13_PHH_LIMIT_TIME) {
if (ctx->phh_count > TLS13_PHH_LIMIT)
return 0;
} else
ctx->phh_count = 0;
ctx->phh_count++;
ctx->phh_last_seen = now;
return 1;
}
static ssize_t
tls13_key_update_recv(struct tls13_ctx *ctx, CBS *cbs)
{
struct tls13_handshake_msg *hs_msg = NULL;
CBB cbb_hs;
CBS cbs_hs;
uint8_t alert = TLS13_ALERT_INTERNAL_ERROR;
uint8_t key_update_request;
ssize_t ret;
if (!CBS_get_u8(cbs, &key_update_request)) {
alert = TLS13_ALERT_DECODE_ERROR;
goto err;
}
if (CBS_len(cbs) != 0) {
alert = TLS13_ALERT_DECODE_ERROR;
goto err;
}
if (key_update_request > 1) {
alert = TLS13_ALERT_ILLEGAL_PARAMETER;
goto err;
}
if (!tls13_phh_update_peer_traffic_secret(ctx))
goto err;
if (key_update_request == 0)
return TLS13_IO_SUCCESS;
/* key_update_request == 1 */
if ((hs_msg = tls13_handshake_msg_new()) == NULL)
goto err;
if (!tls13_handshake_msg_start(hs_msg, &cbb_hs, TLS13_MT_KEY_UPDATE))
goto err;
if (!CBB_add_u8(&cbb_hs, 0))
goto err;
if (!tls13_handshake_msg_finish(hs_msg))
goto err;
ctx->key_update_request = 1;
tls13_handshake_msg_data(hs_msg, &cbs_hs);
ret = tls13_record_layer_phh(ctx->rl, &cbs_hs);
tls13_handshake_msg_free(hs_msg);
hs_msg = NULL;
return ret;
err:
tls13_handshake_msg_free(hs_msg);
return tls13_send_alert(ctx->rl, alert);
}
static void
tls13_phh_done_cb(void *cb_arg)
{
struct tls13_ctx *ctx = cb_arg;
if (ctx->key_update_request) {
tls13_phh_update_local_traffic_secret(ctx);
ctx->key_update_request = 0;
}
}
static ssize_t
tls13_phh_received_cb(void *cb_arg, CBS *cbs)
{
ssize_t ret = TLS13_IO_FAILURE;
struct tls13_ctx *ctx = cb_arg;
CBS phh_cbs;
if (!tls13_phh_limit_check(ctx))
return tls13_send_alert(ctx->rl, TLS13_ALERT_UNEXPECTED_MESSAGE);
if ((ctx->hs_msg == NULL) &&
((ctx->hs_msg = tls13_handshake_msg_new()) == NULL))
return TLS13_IO_FAILURE;
if (!tls13_handshake_msg_set_buffer(ctx->hs_msg, cbs))
return TLS13_IO_FAILURE;
if ((ret = tls13_handshake_msg_recv(ctx->hs_msg, ctx->rl))
!= TLS13_IO_SUCCESS)
return ret;
if (!tls13_handshake_msg_content(ctx->hs_msg, &phh_cbs))
return TLS13_IO_FAILURE;
switch(tls13_handshake_msg_type(ctx->hs_msg)) {
case TLS13_MT_KEY_UPDATE:
ret = tls13_key_update_recv(ctx, &phh_cbs);
break;
case TLS13_MT_NEW_SESSION_TICKET:
/* XXX do nothing for now and ignore this */
break;
case TLS13_MT_CERTIFICATE_REQUEST:
/* XXX add support if we choose to advertise this */
/* FALLTHROUGH */
default:
ret = TLS13_IO_FAILURE; /* XXX send alert */
break;
}
tls13_handshake_msg_free(ctx->hs_msg);
ctx->hs_msg = NULL;
return ret;
}
static const struct tls13_record_layer_callbacks rl_callbacks = {
.wire_read = tls13_legacy_wire_read_cb,
.wire_write = tls13_legacy_wire_write_cb,
.wire_flush = tls13_legacy_wire_flush_cb,
.alert_recv = tls13_alert_received_cb,
.alert_sent = tls13_alert_sent_cb,
.phh_recv = tls13_phh_received_cb,
.phh_sent = tls13_phh_done_cb,
};
struct tls13_ctx *
tls13_ctx_new(int mode)
{
struct tls13_ctx *ctx = NULL;
if ((ctx = calloc(sizeof(struct tls13_ctx), 1)) == NULL)
goto err;
ctx->mode = mode;
if ((ctx->rl = tls13_record_layer_new(&rl_callbacks, ctx)) == NULL)
goto err;
ctx->handshake_message_sent_cb = tls13_legacy_handshake_message_sent_cb;
ctx->handshake_message_recv_cb = tls13_legacy_handshake_message_recv_cb;
ctx->info_cb = tls13_legacy_info_cb;
ctx->ocsp_status_recv_cb = tls13_legacy_ocsp_status_recv_cb;
ctx->middlebox_compat = 1;
return ctx;
err:
tls13_ctx_free(ctx);
return NULL;
}
void
tls13_ctx_free(struct tls13_ctx *ctx)
{
if (ctx == NULL)
return;
tls13_error_clear(&ctx->error);
tls13_record_layer_free(ctx->rl);
tls13_handshake_msg_free(ctx->hs_msg);
freezero(ctx, sizeof(struct tls13_ctx));
}
int
tls13_cert_add(struct tls13_ctx *ctx, CBB *cbb, X509 *cert,
int (*build_extensions)(SSL *s, uint16_t msg_type, CBB *cbb))
{
CBB cert_data, cert_exts;
uint8_t *data;
int cert_len;
if ((cert_len = i2d_X509(cert, NULL)) < 0)
return 0;
if (!CBB_add_u24_length_prefixed(cbb, &cert_data))
return 0;
if (!CBB_add_space(&cert_data, &data, cert_len))
return 0;
if (i2d_X509(cert, &data) != cert_len)
return 0;
if (build_extensions != NULL) {
if (!build_extensions(ctx->ssl, SSL_TLSEXT_MSG_CT, cbb))
return 0;
} else {
if (!CBB_add_u16_length_prefixed(cbb, &cert_exts))
return 0;
}
if (!CBB_flush(cbb))
return 0;
return 1;
}
int
tls13_synthetic_handshake_message(struct tls13_ctx *ctx)
{
struct tls13_handshake_msg *hm = NULL;
unsigned char buf[EVP_MAX_MD_SIZE];
size_t hash_len;
CBB cbb;
CBS cbs;
SSL *s = ctx->ssl;
int ret = 0;
/*
* Replace ClientHello with synthetic handshake message - see
* RFC 8446 section 4.4.1.
*/
if (!tls1_transcript_hash_init(s))
goto err;
if (!tls1_transcript_hash_value(s, buf, sizeof(buf), &hash_len))
goto err;
if ((hm = tls13_handshake_msg_new()) == NULL)
goto err;
if (!tls13_handshake_msg_start(hm, &cbb, TLS13_MT_MESSAGE_HASH))
goto err;
if (!CBB_add_bytes(&cbb, buf, hash_len))
goto err;
if (!tls13_handshake_msg_finish(hm))
goto err;
tls13_handshake_msg_data(hm, &cbs);
tls1_transcript_reset(ctx->ssl);
if (!tls1_transcript_record(ctx->ssl, CBS_data(&cbs), CBS_len(&cbs)))
goto err;
ret = 1;
err:
tls13_handshake_msg_free(hm);
return ret;
}
int
tls13_clienthello_hash_init(struct tls13_ctx *ctx)
{
if (ctx->hs->tls13.clienthello_md_ctx != NULL)
return 0;
if ((ctx->hs->tls13.clienthello_md_ctx = EVP_MD_CTX_new()) == NULL)
return 0;
if (!EVP_DigestInit_ex(ctx->hs->tls13.clienthello_md_ctx,
EVP_sha256(), NULL))
return 0;
if ((ctx->hs->tls13.clienthello_hash == NULL) &&
(ctx->hs->tls13.clienthello_hash = calloc(1, EVP_MAX_MD_SIZE)) ==
NULL)
return 0;
return 1;
}
void
tls13_clienthello_hash_clear(struct ssl_handshake_tls13_st *hs) /* XXX */
{
EVP_MD_CTX_free(hs->clienthello_md_ctx);
hs->clienthello_md_ctx = NULL;
freezero(hs->clienthello_hash, EVP_MAX_MD_SIZE);
hs->clienthello_hash = NULL;
}
int
tls13_clienthello_hash_update_bytes(struct tls13_ctx *ctx, void *data,
size_t len)
{
return EVP_DigestUpdate(ctx->hs->tls13.clienthello_md_ctx, data, len);
}
int
tls13_clienthello_hash_update(struct tls13_ctx *ctx, CBS *cbs)
{
return tls13_clienthello_hash_update_bytes(ctx, (void *)CBS_data(cbs),
CBS_len(cbs));
}
int
tls13_clienthello_hash_finalize(struct tls13_ctx *ctx)
{
if (!EVP_DigestFinal_ex(ctx->hs->tls13.clienthello_md_ctx,
ctx->hs->tls13.clienthello_hash,
&ctx->hs->tls13.clienthello_hash_len))
return 0;
EVP_MD_CTX_free(ctx->hs->tls13.clienthello_md_ctx);
ctx->hs->tls13.clienthello_md_ctx = NULL;
return 1;
}
int
tls13_clienthello_hash_validate(struct tls13_ctx *ctx)
{
unsigned char new_ch_hash[EVP_MAX_MD_SIZE];
unsigned int new_ch_hash_len;
if (ctx->hs->tls13.clienthello_hash == NULL)
return 0;
if (!EVP_DigestFinal_ex(ctx->hs->tls13.clienthello_md_ctx,
new_ch_hash, &new_ch_hash_len))
return 0;
EVP_MD_CTX_free(ctx->hs->tls13.clienthello_md_ctx);
ctx->hs->tls13.clienthello_md_ctx = NULL;
if (ctx->hs->tls13.clienthello_hash_len != new_ch_hash_len)
return 0;
if (memcmp(ctx->hs->tls13.clienthello_hash, new_ch_hash,
new_ch_hash_len) != 0)
return 0;
return 1;
}
int
tls13_exporter(struct tls13_ctx *ctx, const uint8_t *label, size_t label_len,
const uint8_t *context_value, size_t context_value_len, uint8_t *out,
size_t out_len)
{
struct tls13_secret context, export_out, export_secret;
struct tls13_secrets *secrets = ctx->hs->tls13.secrets;
EVP_MD_CTX *md_ctx = NULL;
unsigned int md_out_len;
int md_len;
int ret = 0;
/*
* RFC 8446 Section 7.5.
*/
memset(&context, 0, sizeof(context));
memset(&export_secret, 0, sizeof(export_secret));
export_out.data = out;
export_out.len = out_len;
if (!ctx->handshake_completed)
return 0;
md_len = EVP_MD_size(secrets->digest);
if (md_len <= 0 || md_len > EVP_MAX_MD_SIZE)
goto err;
if (!tls13_secret_init(&export_secret, md_len))
goto err;
if (!tls13_secret_init(&context, md_len))
goto err;
/* In TLSv1.3 no context is equivalent to an empty context. */
if (context_value == NULL) {
context_value = "";
context_value_len = 0;
}
if ((md_ctx = EVP_MD_CTX_new()) == NULL)
goto err;
if (!EVP_DigestInit_ex(md_ctx, secrets->digest, NULL))
goto err;
if (!EVP_DigestUpdate(md_ctx, context_value, context_value_len))
goto err;
if (!EVP_DigestFinal_ex(md_ctx, context.data, &md_out_len))
goto err;
if (md_len != md_out_len)
goto err;
if (!tls13_derive_secret_with_label_length(&export_secret,
secrets->digest, &secrets->exporter_master, label, label_len,
&secrets->empty_hash))
goto err;
if (!tls13_hkdf_expand_label(&export_out, secrets->digest,
&export_secret, "exporter", &context))
goto err;
ret = 1;
err:
EVP_MD_CTX_free(md_ctx);
tls13_secret_cleanup(&context);
tls13_secret_cleanup(&export_secret);
return ret;
}