pineapple-src/externals/libressl/ssl/tls13_handshake.c
2022-04-24 22:29:35 +02:00

723 lines
18 KiB
C
Executable file

/* $OpenBSD: tls13_handshake.c,v 1.70 2021/09/16 19:25:30 jsing Exp $ */
/*
* Copyright (c) 2018-2021 Theo Buehler <tb@openbsd.org>
* Copyright (c) 2019 Joel Sing <jsing@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 "ssl_locl.h"
#include "tls13_handshake.h"
#include "tls13_internal.h"
/* Based on RFC 8446 and inspired by s2n's TLS 1.2 state machine. */
struct tls13_handshake_action {
uint8_t handshake_type;
uint8_t sender;
uint8_t handshake_complete;
uint8_t send_preserve_transcript_hash;
uint8_t recv_preserve_transcript_hash;
int (*send)(struct tls13_ctx *ctx, CBB *cbb);
int (*sent)(struct tls13_ctx *ctx);
int (*recv)(struct tls13_ctx *ctx, CBS *cbs);
};
static enum tls13_message_type
tls13_handshake_active_state(struct tls13_ctx *ctx);
static const struct tls13_handshake_action *
tls13_handshake_active_action(struct tls13_ctx *ctx);
static int tls13_handshake_advance_state_machine(struct tls13_ctx *ctx);
static int tls13_handshake_send_action(struct tls13_ctx *ctx,
const struct tls13_handshake_action *action);
static int tls13_handshake_recv_action(struct tls13_ctx *ctx,
const struct tls13_handshake_action *action);
static int tls13_handshake_set_legacy_state(struct tls13_ctx *ctx);
static int tls13_handshake_legacy_info_callback(struct tls13_ctx *ctx);
static const struct tls13_handshake_action state_machine[] = {
[CLIENT_HELLO] = {
.handshake_type = TLS13_MT_CLIENT_HELLO,
.sender = TLS13_HS_CLIENT,
.send = tls13_client_hello_send,
.sent = tls13_client_hello_sent,
.recv = tls13_client_hello_recv,
},
[CLIENT_HELLO_RETRY] = {
.handshake_type = TLS13_MT_CLIENT_HELLO,
.sender = TLS13_HS_CLIENT,
.send = tls13_client_hello_retry_send,
.recv = tls13_client_hello_retry_recv,
},
[CLIENT_END_OF_EARLY_DATA] = {
.handshake_type = TLS13_MT_END_OF_EARLY_DATA,
.sender = TLS13_HS_CLIENT,
.send = tls13_client_end_of_early_data_send,
.recv = tls13_client_end_of_early_data_recv,
},
[CLIENT_CERTIFICATE] = {
.handshake_type = TLS13_MT_CERTIFICATE,
.sender = TLS13_HS_CLIENT,
.send_preserve_transcript_hash = 1,
.send = tls13_client_certificate_send,
.recv = tls13_client_certificate_recv,
},
[CLIENT_CERTIFICATE_VERIFY] = {
.handshake_type = TLS13_MT_CERTIFICATE_VERIFY,
.sender = TLS13_HS_CLIENT,
.recv_preserve_transcript_hash = 1,
.send = tls13_client_certificate_verify_send,
.recv = tls13_client_certificate_verify_recv,
},
[CLIENT_FINISHED] = {
.handshake_type = TLS13_MT_FINISHED,
.sender = TLS13_HS_CLIENT,
.recv_preserve_transcript_hash = 1,
.send = tls13_client_finished_send,
.sent = tls13_client_finished_sent,
.recv = tls13_client_finished_recv,
},
[SERVER_HELLO] = {
.handshake_type = TLS13_MT_SERVER_HELLO,
.sender = TLS13_HS_SERVER,
.send = tls13_server_hello_send,
.sent = tls13_server_hello_sent,
.recv = tls13_server_hello_recv,
},
[SERVER_HELLO_RETRY_REQUEST] = {
.handshake_type = TLS13_MT_SERVER_HELLO,
.sender = TLS13_HS_SERVER,
.send = tls13_server_hello_retry_request_send,
.recv = tls13_server_hello_retry_request_recv,
.sent = tls13_server_hello_retry_request_sent,
},
[SERVER_ENCRYPTED_EXTENSIONS] = {
.handshake_type = TLS13_MT_ENCRYPTED_EXTENSIONS,
.sender = TLS13_HS_SERVER,
.send = tls13_server_encrypted_extensions_send,
.recv = tls13_server_encrypted_extensions_recv,
},
[SERVER_CERTIFICATE] = {
.handshake_type = TLS13_MT_CERTIFICATE,
.sender = TLS13_HS_SERVER,
.send_preserve_transcript_hash = 1,
.send = tls13_server_certificate_send,
.recv = tls13_server_certificate_recv,
},
[SERVER_CERTIFICATE_REQUEST] = {
.handshake_type = TLS13_MT_CERTIFICATE_REQUEST,
.sender = TLS13_HS_SERVER,
.send = tls13_server_certificate_request_send,
.recv = tls13_server_certificate_request_recv,
},
[SERVER_CERTIFICATE_VERIFY] = {
.handshake_type = TLS13_MT_CERTIFICATE_VERIFY,
.sender = TLS13_HS_SERVER,
.recv_preserve_transcript_hash = 1,
.send = tls13_server_certificate_verify_send,
.recv = tls13_server_certificate_verify_recv,
},
[SERVER_FINISHED] = {
.handshake_type = TLS13_MT_FINISHED,
.sender = TLS13_HS_SERVER,
.recv_preserve_transcript_hash = 1,
.send_preserve_transcript_hash = 1,
.send = tls13_server_finished_send,
.sent = tls13_server_finished_sent,
.recv = tls13_server_finished_recv,
},
[APPLICATION_DATA] = {
.handshake_complete = 1,
},
};
const enum tls13_message_type handshakes[][TLS13_NUM_MESSAGE_TYPES] = {
[INITIAL] = {
CLIENT_HELLO,
SERVER_HELLO_RETRY_REQUEST,
CLIENT_HELLO_RETRY,
SERVER_HELLO,
},
[NEGOTIATED] = {
CLIENT_HELLO,
SERVER_HELLO_RETRY_REQUEST,
CLIENT_HELLO_RETRY,
SERVER_HELLO,
SERVER_ENCRYPTED_EXTENSIONS,
SERVER_CERTIFICATE_REQUEST,
SERVER_CERTIFICATE,
SERVER_CERTIFICATE_VERIFY,
SERVER_FINISHED,
CLIENT_CERTIFICATE,
CLIENT_FINISHED,
APPLICATION_DATA,
},
[NEGOTIATED | WITHOUT_HRR] = {
CLIENT_HELLO,
SERVER_HELLO,
SERVER_ENCRYPTED_EXTENSIONS,
SERVER_CERTIFICATE_REQUEST,
SERVER_CERTIFICATE,
SERVER_CERTIFICATE_VERIFY,
SERVER_FINISHED,
CLIENT_CERTIFICATE,
CLIENT_FINISHED,
APPLICATION_DATA,
},
[NEGOTIATED | WITHOUT_CR] = {
CLIENT_HELLO,
SERVER_HELLO_RETRY_REQUEST,
CLIENT_HELLO_RETRY,
SERVER_HELLO,
SERVER_ENCRYPTED_EXTENSIONS,
SERVER_CERTIFICATE,
SERVER_CERTIFICATE_VERIFY,
SERVER_FINISHED,
CLIENT_FINISHED,
APPLICATION_DATA,
},
[NEGOTIATED | WITHOUT_HRR | WITHOUT_CR] = {
CLIENT_HELLO,
SERVER_HELLO,
SERVER_ENCRYPTED_EXTENSIONS,
SERVER_CERTIFICATE,
SERVER_CERTIFICATE_VERIFY,
SERVER_FINISHED,
CLIENT_FINISHED,
APPLICATION_DATA,
},
[NEGOTIATED | WITH_PSK] = {
CLIENT_HELLO,
SERVER_HELLO_RETRY_REQUEST,
CLIENT_HELLO_RETRY,
SERVER_HELLO,
SERVER_ENCRYPTED_EXTENSIONS,
SERVER_FINISHED,
CLIENT_FINISHED,
APPLICATION_DATA,
},
[NEGOTIATED | WITHOUT_HRR | WITH_PSK] = {
CLIENT_HELLO,
SERVER_HELLO,
SERVER_ENCRYPTED_EXTENSIONS,
SERVER_FINISHED,
CLIENT_FINISHED,
APPLICATION_DATA,
},
[NEGOTIATED | WITH_CCV] = {
CLIENT_HELLO,
SERVER_HELLO_RETRY_REQUEST,
CLIENT_HELLO_RETRY,
SERVER_HELLO,
SERVER_ENCRYPTED_EXTENSIONS,
SERVER_CERTIFICATE_REQUEST,
SERVER_CERTIFICATE,
SERVER_CERTIFICATE_VERIFY,
SERVER_FINISHED,
CLIENT_CERTIFICATE,
CLIENT_CERTIFICATE_VERIFY,
CLIENT_FINISHED,
APPLICATION_DATA,
},
[NEGOTIATED | WITHOUT_HRR | WITH_CCV] = {
CLIENT_HELLO,
SERVER_HELLO,
SERVER_ENCRYPTED_EXTENSIONS,
SERVER_CERTIFICATE_REQUEST,
SERVER_CERTIFICATE,
SERVER_CERTIFICATE_VERIFY,
SERVER_FINISHED,
CLIENT_CERTIFICATE,
CLIENT_CERTIFICATE_VERIFY,
CLIENT_FINISHED,
APPLICATION_DATA,
},
};
const size_t handshake_count = sizeof(handshakes) / sizeof(handshakes[0]);
#ifndef TLS13_DEBUG
#define DEBUGF(...)
#else
#define DEBUGF(...) fprintf(stderr, __VA_ARGS__)
static const char *
tls13_handshake_mode_name(uint8_t mode)
{
switch (mode) {
case TLS13_HS_CLIENT:
return "Client";
case TLS13_HS_SERVER:
return "Server";
}
return "Unknown";
}
static const char *
tls13_handshake_message_name(uint8_t msg_type)
{
switch (msg_type) {
case TLS13_MT_CLIENT_HELLO:
return "ClientHello";
case TLS13_MT_SERVER_HELLO:
return "ServerHello";
case TLS13_MT_NEW_SESSION_TICKET:
return "NewSessionTicket";
case TLS13_MT_END_OF_EARLY_DATA:
return "EndOfEarlyData";
case TLS13_MT_ENCRYPTED_EXTENSIONS:
return "EncryptedExtensions";
case TLS13_MT_CERTIFICATE:
return "Certificate";
case TLS13_MT_CERTIFICATE_REQUEST:
return "CertificateRequest";
case TLS13_MT_CERTIFICATE_VERIFY:
return "CertificateVerify";
case TLS13_MT_FINISHED:
return "Finished";
case TLS13_MT_KEY_UPDATE:
return "KeyUpdate";
}
return "Unknown";
}
#endif
static enum tls13_message_type
tls13_handshake_active_state(struct tls13_ctx *ctx)
{
struct tls13_handshake_stage hs = ctx->handshake_stage;
if (hs.hs_type >= handshake_count)
return INVALID;
if (hs.message_number >= TLS13_NUM_MESSAGE_TYPES)
return INVALID;
return handshakes[hs.hs_type][hs.message_number];
}
static const struct tls13_handshake_action *
tls13_handshake_active_action(struct tls13_ctx *ctx)
{
enum tls13_message_type mt = tls13_handshake_active_state(ctx);
if (mt == INVALID)
return NULL;
return &state_machine[mt];
}
static int
tls13_handshake_advance_state_machine(struct tls13_ctx *ctx)
{
if (++ctx->handshake_stage.message_number >= TLS13_NUM_MESSAGE_TYPES)
return 0;
return 1;
}
static int
tls13_handshake_end_of_flight(struct tls13_ctx *ctx,
const struct tls13_handshake_action *previous)
{
const struct tls13_handshake_action *current;
if ((current = tls13_handshake_active_action(ctx)) == NULL)
return 1;
return current->sender != previous->sender;
}
int
tls13_handshake_msg_record(struct tls13_ctx *ctx)
{
CBS cbs;
tls13_handshake_msg_data(ctx->hs_msg, &cbs);
return tls1_transcript_record(ctx->ssl, CBS_data(&cbs), CBS_len(&cbs));
}
int
tls13_handshake_perform(struct tls13_ctx *ctx)
{
const struct tls13_handshake_action *action;
int sending;
int ret;
if (!ctx->handshake_started) {
/*
* Set legacy state to connect/accept and call info callback
* to signal that the handshake started.
*/
if (!tls13_handshake_set_legacy_state(ctx))
return TLS13_IO_FAILURE;
if (!tls13_handshake_legacy_info_callback(ctx))
return TLS13_IO_FAILURE;
ctx->handshake_started = 1;
/* Set legacy state for initial ClientHello read or write. */
if (!tls13_handshake_set_legacy_state(ctx))
return TLS13_IO_FAILURE;
}
for (;;) {
if ((action = tls13_handshake_active_action(ctx)) == NULL)
return TLS13_IO_FAILURE;
if (ctx->need_flush) {
if ((ret = tls13_record_layer_flush(ctx->rl)) !=
TLS13_IO_SUCCESS)
return ret;
ctx->need_flush = 0;
}
if (action->handshake_complete) {
ctx->handshake_completed = 1;
tls13_record_layer_handshake_completed(ctx->rl);
if (!tls13_handshake_set_legacy_state(ctx))
return TLS13_IO_FAILURE;
if (!tls13_handshake_legacy_info_callback(ctx))
return TLS13_IO_FAILURE;
return TLS13_IO_SUCCESS;
}
sending = action->sender == ctx->mode;
DEBUGF("%s %s %s\n", tls13_handshake_mode_name(ctx->mode),
sending ? "sending" : "receiving",
tls13_handshake_message_name(action->handshake_type));
if (ctx->alert != 0)
return tls13_send_alert(ctx->rl, ctx->alert);
if (sending)
ret = tls13_handshake_send_action(ctx, action);
else
ret = tls13_handshake_recv_action(ctx, action);
if (ctx->alert != 0)
return tls13_send_alert(ctx->rl, ctx->alert);
if (ret <= 0) {
DEBUGF("%s %s returned %d\n",
tls13_handshake_mode_name(ctx->mode),
(action->sender == ctx->mode) ? "send" : "recv",
ret);
return ret;
}
if (!tls13_handshake_legacy_info_callback(ctx))
return TLS13_IO_FAILURE;
if (!tls13_handshake_advance_state_machine(ctx))
return TLS13_IO_FAILURE;
if (sending)
ctx->need_flush = tls13_handshake_end_of_flight(ctx,
action);
if (!tls13_handshake_set_legacy_state(ctx))
return TLS13_IO_FAILURE;
}
}
static int
tls13_handshake_send_action(struct tls13_ctx *ctx,
const struct tls13_handshake_action *action)
{
ssize_t ret;
CBB cbb;
if (ctx->send_dummy_ccs) {
if ((ret = tls13_send_dummy_ccs(ctx->rl)) != TLS13_IO_SUCCESS)
return ret;
ctx->send_dummy_ccs = 0;
if (ctx->send_dummy_ccs_after) {
ctx->send_dummy_ccs_after = 0;
return TLS13_IO_SUCCESS;
}
}
/* If we have no handshake message, we need to build one. */
if (ctx->hs_msg == NULL) {
if ((ctx->hs_msg = tls13_handshake_msg_new()) == NULL)
return TLS13_IO_FAILURE;
if (!tls13_handshake_msg_start(ctx->hs_msg, &cbb,
action->handshake_type))
return TLS13_IO_FAILURE;
if (!action->send(ctx, &cbb))
return TLS13_IO_FAILURE;
if (!tls13_handshake_msg_finish(ctx->hs_msg))
return TLS13_IO_FAILURE;
}
if ((ret = tls13_handshake_msg_send(ctx->hs_msg, ctx->rl)) <= 0)
return ret;
if (!tls13_handshake_msg_record(ctx))
return TLS13_IO_FAILURE;
if (action->send_preserve_transcript_hash) {
if (!tls1_transcript_hash_value(ctx->ssl,
ctx->hs->tls13.transcript_hash,
sizeof(ctx->hs->tls13.transcript_hash),
&ctx->hs->tls13.transcript_hash_len))
return TLS13_IO_FAILURE;
}
if (ctx->handshake_message_sent_cb != NULL)
ctx->handshake_message_sent_cb(ctx);
tls13_handshake_msg_free(ctx->hs_msg);
ctx->hs_msg = NULL;
if (action->sent != NULL && !action->sent(ctx))
return TLS13_IO_FAILURE;
if (ctx->send_dummy_ccs_after) {
ctx->send_dummy_ccs = 1;
if ((ret = tls13_send_dummy_ccs(ctx->rl)) != TLS13_IO_SUCCESS)
return ret;
ctx->send_dummy_ccs = 0;
ctx->send_dummy_ccs_after = 0;
}
return TLS13_IO_SUCCESS;
}
static int
tls13_handshake_recv_action(struct tls13_ctx *ctx,
const struct tls13_handshake_action *action)
{
uint8_t msg_type;
ssize_t ret;
CBS cbs;
if (ctx->hs_msg == NULL) {
if ((ctx->hs_msg = tls13_handshake_msg_new()) == NULL)
return TLS13_IO_FAILURE;
}
if ((ret = tls13_handshake_msg_recv(ctx->hs_msg, ctx->rl)) <= 0)
return ret;
if (action->recv_preserve_transcript_hash) {
if (!tls1_transcript_hash_value(ctx->ssl,
ctx->hs->tls13.transcript_hash,
sizeof(ctx->hs->tls13.transcript_hash),
&ctx->hs->tls13.transcript_hash_len))
return TLS13_IO_FAILURE;
}
if (!tls13_handshake_msg_record(ctx))
return TLS13_IO_FAILURE;
if (ctx->handshake_message_recv_cb != NULL)
ctx->handshake_message_recv_cb(ctx);
/*
* In TLSv1.3 there is no way to know if you're going to receive a
* certificate request message or not, hence we have to special case it
* here. The receive handler also knows how to deal with this situation.
*/
msg_type = tls13_handshake_msg_type(ctx->hs_msg);
if (msg_type != action->handshake_type &&
(msg_type != TLS13_MT_CERTIFICATE ||
action->handshake_type != TLS13_MT_CERTIFICATE_REQUEST))
return tls13_send_alert(ctx->rl, TLS13_ALERT_UNEXPECTED_MESSAGE);
if (!tls13_handshake_msg_content(ctx->hs_msg, &cbs))
return TLS13_IO_FAILURE;
ret = TLS13_IO_FAILURE;
if (action->recv(ctx, &cbs)) {
if (CBS_len(&cbs) != 0) {
tls13_set_errorx(ctx, TLS13_ERR_TRAILING_DATA, 0,
"trailing data in handshake message", NULL);
ctx->alert = TLS13_ALERT_DECODE_ERROR;
} else {
ret = TLS13_IO_SUCCESS;
}
}
tls13_handshake_msg_free(ctx->hs_msg);
ctx->hs_msg = NULL;
if (ctx->ssl->method->version < TLS1_3_VERSION)
return TLS13_IO_USE_LEGACY;
return ret;
}
struct tls13_handshake_legacy_state {
int recv;
int send;
};
static const struct tls13_handshake_legacy_state legacy_states[] = {
[CLIENT_HELLO] = {
.recv = SSL3_ST_SR_CLNT_HELLO_A,
.send = SSL3_ST_CW_CLNT_HELLO_A,
},
[SERVER_HELLO_RETRY_REQUEST] = {
.recv = SSL3_ST_CR_SRVR_HELLO_A,
.send = SSL3_ST_SW_SRVR_HELLO_A,
},
[CLIENT_HELLO_RETRY] = {
.recv = SSL3_ST_SR_CLNT_HELLO_A,
.send = SSL3_ST_CW_CLNT_HELLO_A,
},
[SERVER_HELLO] = {
.recv = SSL3_ST_CR_SRVR_HELLO_A,
.send = SSL3_ST_SW_SRVR_HELLO_A,
},
[SERVER_ENCRYPTED_EXTENSIONS] = {
.send = 0,
.recv = 0,
},
[SERVER_CERTIFICATE_REQUEST] = {
.recv = SSL3_ST_CR_CERT_REQ_A,
.send = SSL3_ST_SW_CERT_REQ_A,
},
[SERVER_CERTIFICATE] = {
.recv = SSL3_ST_CR_CERT_A,
.send = SSL3_ST_SW_CERT_A,
},
[SERVER_CERTIFICATE_VERIFY] = {
.send = 0,
.recv = 0,
},
[SERVER_FINISHED] = {
.recv = SSL3_ST_CR_FINISHED_A,
.send = SSL3_ST_SW_FINISHED_A,
},
[CLIENT_END_OF_EARLY_DATA] = {
.send = 0,
.recv = 0,
},
[CLIENT_CERTIFICATE] = {
.recv = SSL3_ST_SR_CERT_VRFY_A,
.send = SSL3_ST_CW_CERT_VRFY_B,
},
[CLIENT_CERTIFICATE_VERIFY] = {
.send = 0,
.recv = 0,
},
[CLIENT_FINISHED] = {
.recv = SSL3_ST_SR_FINISHED_A,
.send = SSL3_ST_CW_FINISHED_A,
},
[APPLICATION_DATA] = {
.recv = 0,
.send = 0,
},
};
CTASSERT(sizeof(state_machine) / sizeof(state_machine[0]) ==
sizeof(legacy_states) / sizeof(legacy_states[0]));
static int
tls13_handshake_legacy_state(struct tls13_ctx *ctx, int *out_state)
{
const struct tls13_handshake_action *action;
enum tls13_message_type mt;
*out_state = 0;
if (!ctx->handshake_started) {
if (ctx->mode == TLS13_HS_CLIENT)
*out_state = SSL_ST_CONNECT;
else
*out_state = SSL_ST_ACCEPT;
return 1;
}
if (ctx->handshake_completed) {
*out_state = SSL_ST_OK;
return 1;
}
if ((mt = tls13_handshake_active_state(ctx)) == INVALID)
return 0;
if ((action = tls13_handshake_active_action(ctx)) == NULL)
return 0;
if (action->sender == ctx->mode)
*out_state = legacy_states[mt].send;
else
*out_state = legacy_states[mt].recv;
return 1;
}
static int
tls13_handshake_info_position(struct tls13_ctx *ctx)
{
if (!ctx->handshake_started)
return TLS13_INFO_HANDSHAKE_STARTED;
if (ctx->handshake_completed)
return TLS13_INFO_HANDSHAKE_COMPLETED;
if (ctx->mode == TLS13_HS_CLIENT)
return TLS13_INFO_CONNECT_LOOP;
else
return TLS13_INFO_ACCEPT_LOOP;
}
static int
tls13_handshake_legacy_info_callback(struct tls13_ctx *ctx)
{
int state, where;
if (!tls13_handshake_legacy_state(ctx, &state))
return 0;
/* Do nothing if there's no corresponding legacy state. */
if (state == 0)
return 1;
if (ctx->info_cb != NULL) {
where = tls13_handshake_info_position(ctx);
ctx->info_cb(ctx, where, 1);
}
return 1;
}
static int
tls13_handshake_set_legacy_state(struct tls13_ctx *ctx)
{
int state;
if (!tls13_handshake_legacy_state(ctx, &state))
return 0;
/* Do nothing if there's no corresponding legacy state. */
if (state == 0)
return 1;
ctx->hs->state = state;
return 1;
}