973 lines
30 KiB
C
973 lines
30 KiB
C
/*
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* Copyright 2015-2019 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include "internal/cryptlib.h"
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#include <openssl/rand.h>
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#include "../ssl_locl.h"
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#include "statem_locl.h"
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#include <assert.h>
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/*
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* This file implements the SSL/TLS/DTLS state machines.
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*
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* There are two primary state machines:
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*
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* 1) Message flow state machine
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* 2) Handshake state machine
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*
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* The Message flow state machine controls the reading and sending of messages
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* including handling of non-blocking IO events, flushing of the underlying
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* write BIO, handling unexpected messages, etc. It is itself broken into two
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* separate sub-state machines which control reading and writing respectively.
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*
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* The Handshake state machine keeps track of the current SSL/TLS handshake
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* state. Transitions of the handshake state are the result of events that
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* occur within the Message flow state machine.
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*
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* Overall it looks like this:
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*
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* --------------------------------------------- -------------------
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* | | | |
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* | Message flow state machine | | |
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* | | | |
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* | -------------------- -------------------- | Transition | Handshake state |
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* | | MSG_FLOW_READING | | MSG_FLOW_WRITING | | Event | machine |
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* | | sub-state | | sub-state | |----------->| |
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* | | machine for | | machine for | | | |
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* | | reading messages | | writing messages | | | |
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* | -------------------- -------------------- | | |
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* | | | |
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* --------------------------------------------- -------------------
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*
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*/
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/* Sub state machine return values */
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typedef enum {
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/* Something bad happened or NBIO */
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SUB_STATE_ERROR,
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/* Sub state finished go to the next sub state */
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SUB_STATE_FINISHED,
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/* Sub state finished and handshake was completed */
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SUB_STATE_END_HANDSHAKE
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} SUB_STATE_RETURN;
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static int state_machine(SSL *s, int server);
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static void init_read_state_machine(SSL *s);
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static SUB_STATE_RETURN read_state_machine(SSL *s);
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static void init_write_state_machine(SSL *s);
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static SUB_STATE_RETURN write_state_machine(SSL *s);
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OSSL_HANDSHAKE_STATE SSL_get_state(const SSL *ssl)
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{
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return ssl->statem.hand_state;
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}
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int SSL_in_init(const SSL *s)
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{
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return s->statem.in_init;
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}
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int SSL_is_init_finished(const SSL *s)
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{
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return !(s->statem.in_init) && (s->statem.hand_state == TLS_ST_OK);
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}
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int SSL_in_before(const SSL *s)
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{
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/*
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* Historically being "in before" meant before anything had happened. In the
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* current code though we remain in the "before" state for a while after we
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* have started the handshake process (e.g. as a server waiting for the
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* first message to arrive). There "in before" is taken to mean "in before"
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* and not started any handshake process yet.
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*/
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return (s->statem.hand_state == TLS_ST_BEFORE)
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&& (s->statem.state == MSG_FLOW_UNINITED);
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}
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/*
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* Clear the state machine state and reset back to MSG_FLOW_UNINITED
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*/
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void ossl_statem_clear(SSL *s)
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{
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s->statem.state = MSG_FLOW_UNINITED;
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s->statem.hand_state = TLS_ST_BEFORE;
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s->statem.in_init = 1;
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s->statem.no_cert_verify = 0;
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}
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/*
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* Set the state machine up ready for a renegotiation handshake
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*/
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void ossl_statem_set_renegotiate(SSL *s)
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{
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s->statem.in_init = 1;
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s->statem.request_state = TLS_ST_SW_HELLO_REQ;
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}
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/*
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* Put the state machine into an error state and send an alert if appropriate.
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* This is a permanent error for the current connection.
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*/
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void ossl_statem_fatal(SSL *s, int al, int func, int reason, const char *file,
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int line)
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{
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ERR_put_error(ERR_LIB_SSL, func, reason, file, line);
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/* We shouldn't call SSLfatal() twice. Once is enough */
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if (s->statem.in_init && s->statem.state == MSG_FLOW_ERROR)
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return;
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s->statem.in_init = 1;
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s->statem.state = MSG_FLOW_ERROR;
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if (al != SSL_AD_NO_ALERT
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&& s->statem.enc_write_state != ENC_WRITE_STATE_INVALID)
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ssl3_send_alert(s, SSL3_AL_FATAL, al);
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}
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/*
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* This macro should only be called if we are already expecting to be in
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* a fatal error state. We verify that we are, and set it if not (this would
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* indicate a bug).
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*/
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#define check_fatal(s, f) \
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do { \
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if (!ossl_assert((s)->statem.in_init \
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&& (s)->statem.state == MSG_FLOW_ERROR)) \
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SSLfatal(s, SSL_AD_INTERNAL_ERROR, (f), \
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SSL_R_MISSING_FATAL); \
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} while (0)
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/*
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* Discover whether the current connection is in the error state.
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*
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* Valid return values are:
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* 1: Yes
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* 0: No
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*/
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int ossl_statem_in_error(const SSL *s)
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{
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if (s->statem.state == MSG_FLOW_ERROR)
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return 1;
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return 0;
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}
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void ossl_statem_set_in_init(SSL *s, int init)
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{
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s->statem.in_init = init;
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}
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int ossl_statem_get_in_handshake(SSL *s)
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{
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return s->statem.in_handshake;
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}
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void ossl_statem_set_in_handshake(SSL *s, int inhand)
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{
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if (inhand)
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s->statem.in_handshake++;
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else
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s->statem.in_handshake--;
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}
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/* Are we in a sensible state to skip over unreadable early data? */
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int ossl_statem_skip_early_data(SSL *s)
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{
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if (s->ext.early_data != SSL_EARLY_DATA_REJECTED)
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return 0;
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if (!s->server
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|| s->statem.hand_state != TLS_ST_EARLY_DATA
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|| s->hello_retry_request == SSL_HRR_COMPLETE)
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return 0;
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return 1;
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}
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/*
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* Called when we are in SSL_read*(), SSL_write*(), or SSL_accept()
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* /SSL_connect()/SSL_do_handshake(). Used to test whether we are in an early
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* data state and whether we should attempt to move the handshake on if so.
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* |sending| is 1 if we are attempting to send data (SSL_write*()), 0 if we are
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* attempting to read data (SSL_read*()), or -1 if we are in SSL_do_handshake()
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* or similar.
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*/
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void ossl_statem_check_finish_init(SSL *s, int sending)
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{
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if (sending == -1) {
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if (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END
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|| s->statem.hand_state == TLS_ST_EARLY_DATA) {
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ossl_statem_set_in_init(s, 1);
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if (s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) {
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/*
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* SSL_connect() or SSL_do_handshake() has been called directly.
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* We don't allow any more writing of early data.
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*/
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s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING;
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}
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}
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} else if (!s->server) {
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if ((sending && (s->statem.hand_state == TLS_ST_PENDING_EARLY_DATA_END
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|| s->statem.hand_state == TLS_ST_EARLY_DATA)
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&& s->early_data_state != SSL_EARLY_DATA_WRITING)
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|| (!sending && s->statem.hand_state == TLS_ST_EARLY_DATA)) {
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ossl_statem_set_in_init(s, 1);
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/*
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* SSL_write() has been called directly. We don't allow any more
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* writing of early data.
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*/
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if (sending && s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY)
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s->early_data_state = SSL_EARLY_DATA_FINISHED_WRITING;
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}
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} else {
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if (s->early_data_state == SSL_EARLY_DATA_FINISHED_READING
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&& s->statem.hand_state == TLS_ST_EARLY_DATA)
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ossl_statem_set_in_init(s, 1);
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}
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}
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void ossl_statem_set_hello_verify_done(SSL *s)
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{
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s->statem.state = MSG_FLOW_UNINITED;
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s->statem.in_init = 1;
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/*
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* This will get reset (briefly) back to TLS_ST_BEFORE when we enter
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* state_machine() because |state| is MSG_FLOW_UNINITED, but until then any
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* calls to SSL_in_before() will return false. Also calls to
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* SSL_state_string() and SSL_state_string_long() will return something
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* sensible.
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*/
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s->statem.hand_state = TLS_ST_SR_CLNT_HELLO;
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}
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int ossl_statem_connect(SSL *s)
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{
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return state_machine(s, 0);
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}
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int ossl_statem_accept(SSL *s)
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{
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return state_machine(s, 1);
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}
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typedef void (*info_cb) (const SSL *, int, int);
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static info_cb get_callback(SSL *s)
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{
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if (s->info_callback != NULL)
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return s->info_callback;
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else if (s->ctx->info_callback != NULL)
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return s->ctx->info_callback;
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return NULL;
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}
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/*
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* The main message flow state machine. We start in the MSG_FLOW_UNINITED or
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* MSG_FLOW_FINISHED state and finish in MSG_FLOW_FINISHED. Valid states and
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* transitions are as follows:
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*
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* MSG_FLOW_UNINITED MSG_FLOW_FINISHED
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* | |
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* +-----------------------+
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* v
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* MSG_FLOW_WRITING <---> MSG_FLOW_READING
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* |
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* V
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* MSG_FLOW_FINISHED
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* |
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* V
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* [SUCCESS]
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*
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* We may exit at any point due to an error or NBIO event. If an NBIO event
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* occurs then we restart at the point we left off when we are recalled.
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* MSG_FLOW_WRITING and MSG_FLOW_READING have sub-state machines associated with them.
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*
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* In addition to the above there is also the MSG_FLOW_ERROR state. We can move
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* into that state at any point in the event that an irrecoverable error occurs.
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*
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* Valid return values are:
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* 1: Success
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* <=0: NBIO or error
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*/
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static int state_machine(SSL *s, int server)
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{
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BUF_MEM *buf = NULL;
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void (*cb) (const SSL *ssl, int type, int val) = NULL;
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OSSL_STATEM *st = &s->statem;
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int ret = -1;
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int ssret;
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if (st->state == MSG_FLOW_ERROR) {
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/* Shouldn't have been called if we're already in the error state */
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return -1;
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}
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ERR_clear_error();
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clear_sys_error();
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cb = get_callback(s);
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st->in_handshake++;
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if (!SSL_in_init(s) || SSL_in_before(s)) {
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/*
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* If we are stateless then we already called SSL_clear() - don't do
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* it again and clear the STATELESS flag itself.
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*/
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if ((s->s3->flags & TLS1_FLAGS_STATELESS) == 0 && !SSL_clear(s))
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return -1;
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}
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#ifndef OPENSSL_NO_SCTP
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if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
|
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/*
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* Notify SCTP BIO socket to enter handshake mode and prevent stream
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* identifier other than 0.
|
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*/
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BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
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st->in_handshake, NULL);
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}
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#endif
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|
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/* Initialise state machine */
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if (st->state == MSG_FLOW_UNINITED
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|| st->state == MSG_FLOW_FINISHED) {
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if (st->state == MSG_FLOW_UNINITED) {
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st->hand_state = TLS_ST_BEFORE;
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st->request_state = TLS_ST_BEFORE;
|
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}
|
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|
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s->server = server;
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if (cb != NULL) {
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if (SSL_IS_FIRST_HANDSHAKE(s) || !SSL_IS_TLS13(s))
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cb(s, SSL_CB_HANDSHAKE_START, 1);
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}
|
|
|
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/*
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* Fatal errors in this block don't send an alert because we have
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* failed to even initialise properly. Sending an alert is probably
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* doomed to failure.
|
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*/
|
|
|
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if (SSL_IS_DTLS(s)) {
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if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00) &&
|
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(server || (s->version & 0xff00) != (DTLS1_BAD_VER & 0xff00))) {
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SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
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ERR_R_INTERNAL_ERROR);
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goto end;
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}
|
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} else {
|
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if ((s->version >> 8) != SSL3_VERSION_MAJOR) {
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SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
|
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ERR_R_INTERNAL_ERROR);
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goto end;
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}
|
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}
|
|
|
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if (!ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) {
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SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
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ERR_R_INTERNAL_ERROR);
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goto end;
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}
|
|
|
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if (s->init_buf == NULL) {
|
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if ((buf = BUF_MEM_new()) == NULL) {
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SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
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ERR_R_INTERNAL_ERROR);
|
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goto end;
|
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}
|
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if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
|
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SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
|
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ERR_R_INTERNAL_ERROR);
|
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goto end;
|
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}
|
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s->init_buf = buf;
|
|
buf = NULL;
|
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}
|
|
|
|
if (!ssl3_setup_buffers(s)) {
|
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SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
|
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ERR_R_INTERNAL_ERROR);
|
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goto end;
|
|
}
|
|
s->init_num = 0;
|
|
|
|
/*
|
|
* Should have been reset by tls_process_finished, too.
|
|
*/
|
|
s->s3->change_cipher_spec = 0;
|
|
|
|
/*
|
|
* Ok, we now need to push on a buffering BIO ...but not with
|
|
* SCTP
|
|
*/
|
|
#ifndef OPENSSL_NO_SCTP
|
|
if (!SSL_IS_DTLS(s) || !BIO_dgram_is_sctp(SSL_get_wbio(s)))
|
|
#endif
|
|
if (!ssl_init_wbio_buffer(s)) {
|
|
SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_STATE_MACHINE,
|
|
ERR_R_INTERNAL_ERROR);
|
|
goto end;
|
|
}
|
|
|
|
if ((SSL_in_before(s))
|
|
|| s->renegotiate) {
|
|
if (!tls_setup_handshake(s)) {
|
|
/* SSLfatal() already called */
|
|
goto end;
|
|
}
|
|
|
|
if (SSL_IS_FIRST_HANDSHAKE(s))
|
|
st->read_state_first_init = 1;
|
|
}
|
|
|
|
st->state = MSG_FLOW_WRITING;
|
|
init_write_state_machine(s);
|
|
}
|
|
|
|
while (st->state != MSG_FLOW_FINISHED) {
|
|
if (st->state == MSG_FLOW_READING) {
|
|
ssret = read_state_machine(s);
|
|
if (ssret == SUB_STATE_FINISHED) {
|
|
st->state = MSG_FLOW_WRITING;
|
|
init_write_state_machine(s);
|
|
} else {
|
|
/* NBIO or error */
|
|
goto end;
|
|
}
|
|
} else if (st->state == MSG_FLOW_WRITING) {
|
|
ssret = write_state_machine(s);
|
|
if (ssret == SUB_STATE_FINISHED) {
|
|
st->state = MSG_FLOW_READING;
|
|
init_read_state_machine(s);
|
|
} else if (ssret == SUB_STATE_END_HANDSHAKE) {
|
|
st->state = MSG_FLOW_FINISHED;
|
|
} else {
|
|
/* NBIO or error */
|
|
goto end;
|
|
}
|
|
} else {
|
|
/* Error */
|
|
check_fatal(s, SSL_F_STATE_MACHINE);
|
|
SSLerr(SSL_F_STATE_MACHINE, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
|
|
goto end;
|
|
}
|
|
}
|
|
|
|
ret = 1;
|
|
|
|
end:
|
|
st->in_handshake--;
|
|
|
|
#ifndef OPENSSL_NO_SCTP
|
|
if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
|
|
/*
|
|
* Notify SCTP BIO socket to leave handshake mode and allow stream
|
|
* identifier other than 0.
|
|
*/
|
|
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
|
|
st->in_handshake, NULL);
|
|
}
|
|
#endif
|
|
|
|
BUF_MEM_free(buf);
|
|
if (cb != NULL) {
|
|
if (server)
|
|
cb(s, SSL_CB_ACCEPT_EXIT, ret);
|
|
else
|
|
cb(s, SSL_CB_CONNECT_EXIT, ret);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Initialise the MSG_FLOW_READING sub-state machine
|
|
*/
|
|
static void init_read_state_machine(SSL *s)
|
|
{
|
|
OSSL_STATEM *st = &s->statem;
|
|
|
|
st->read_state = READ_STATE_HEADER;
|
|
}
|
|
|
|
static int grow_init_buf(SSL *s, size_t size) {
|
|
|
|
size_t msg_offset = (char *)s->init_msg - s->init_buf->data;
|
|
|
|
if (!BUF_MEM_grow_clean(s->init_buf, (int)size))
|
|
return 0;
|
|
|
|
if (size < msg_offset)
|
|
return 0;
|
|
|
|
s->init_msg = s->init_buf->data + msg_offset;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* This function implements the sub-state machine when the message flow is in
|
|
* MSG_FLOW_READING. The valid sub-states and transitions are:
|
|
*
|
|
* READ_STATE_HEADER <--+<-------------+
|
|
* | | |
|
|
* v | |
|
|
* READ_STATE_BODY -----+-->READ_STATE_POST_PROCESS
|
|
* | |
|
|
* +----------------------------+
|
|
* v
|
|
* [SUB_STATE_FINISHED]
|
|
*
|
|
* READ_STATE_HEADER has the responsibility for reading in the message header
|
|
* and transitioning the state of the handshake state machine.
|
|
*
|
|
* READ_STATE_BODY reads in the rest of the message and then subsequently
|
|
* processes it.
|
|
*
|
|
* READ_STATE_POST_PROCESS is an optional step that may occur if some post
|
|
* processing activity performed on the message may block.
|
|
*
|
|
* Any of the above states could result in an NBIO event occurring in which case
|
|
* control returns to the calling application. When this function is recalled we
|
|
* will resume in the same state where we left off.
|
|
*/
|
|
static SUB_STATE_RETURN read_state_machine(SSL *s)
|
|
{
|
|
OSSL_STATEM *st = &s->statem;
|
|
int ret, mt;
|
|
size_t len = 0;
|
|
int (*transition) (SSL *s, int mt);
|
|
PACKET pkt;
|
|
MSG_PROCESS_RETURN(*process_message) (SSL *s, PACKET *pkt);
|
|
WORK_STATE(*post_process_message) (SSL *s, WORK_STATE wst);
|
|
size_t (*max_message_size) (SSL *s);
|
|
void (*cb) (const SSL *ssl, int type, int val) = NULL;
|
|
|
|
cb = get_callback(s);
|
|
|
|
if (s->server) {
|
|
transition = ossl_statem_server_read_transition;
|
|
process_message = ossl_statem_server_process_message;
|
|
max_message_size = ossl_statem_server_max_message_size;
|
|
post_process_message = ossl_statem_server_post_process_message;
|
|
} else {
|
|
transition = ossl_statem_client_read_transition;
|
|
process_message = ossl_statem_client_process_message;
|
|
max_message_size = ossl_statem_client_max_message_size;
|
|
post_process_message = ossl_statem_client_post_process_message;
|
|
}
|
|
|
|
if (st->read_state_first_init) {
|
|
s->first_packet = 1;
|
|
st->read_state_first_init = 0;
|
|
}
|
|
|
|
while (1) {
|
|
switch (st->read_state) {
|
|
case READ_STATE_HEADER:
|
|
/* Get the state the peer wants to move to */
|
|
if (SSL_IS_DTLS(s)) {
|
|
/*
|
|
* In DTLS we get the whole message in one go - header and body
|
|
*/
|
|
ret = dtls_get_message(s, &mt, &len);
|
|
} else {
|
|
ret = tls_get_message_header(s, &mt);
|
|
}
|
|
|
|
if (ret == 0) {
|
|
/* Could be non-blocking IO */
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
|
|
if (cb != NULL) {
|
|
/* Notify callback of an impending state change */
|
|
if (s->server)
|
|
cb(s, SSL_CB_ACCEPT_LOOP, 1);
|
|
else
|
|
cb(s, SSL_CB_CONNECT_LOOP, 1);
|
|
}
|
|
/*
|
|
* Validate that we are allowed to move to the new state and move
|
|
* to that state if so
|
|
*/
|
|
if (!transition(s, mt))
|
|
return SUB_STATE_ERROR;
|
|
|
|
if (s->s3->tmp.message_size > max_message_size(s)) {
|
|
SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_READ_STATE_MACHINE,
|
|
SSL_R_EXCESSIVE_MESSAGE_SIZE);
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
|
|
/* dtls_get_message already did this */
|
|
if (!SSL_IS_DTLS(s)
|
|
&& s->s3->tmp.message_size > 0
|
|
&& !grow_init_buf(s, s->s3->tmp.message_size
|
|
+ SSL3_HM_HEADER_LENGTH)) {
|
|
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_READ_STATE_MACHINE,
|
|
ERR_R_BUF_LIB);
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
|
|
st->read_state = READ_STATE_BODY;
|
|
/* Fall through */
|
|
|
|
case READ_STATE_BODY:
|
|
if (!SSL_IS_DTLS(s)) {
|
|
/* We already got this above for DTLS */
|
|
ret = tls_get_message_body(s, &len);
|
|
if (ret == 0) {
|
|
/* Could be non-blocking IO */
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
}
|
|
|
|
s->first_packet = 0;
|
|
if (!PACKET_buf_init(&pkt, s->init_msg, len)) {
|
|
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_READ_STATE_MACHINE,
|
|
ERR_R_INTERNAL_ERROR);
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
ret = process_message(s, &pkt);
|
|
|
|
/* Discard the packet data */
|
|
s->init_num = 0;
|
|
|
|
switch (ret) {
|
|
case MSG_PROCESS_ERROR:
|
|
check_fatal(s, SSL_F_READ_STATE_MACHINE);
|
|
return SUB_STATE_ERROR;
|
|
|
|
case MSG_PROCESS_FINISHED_READING:
|
|
if (SSL_IS_DTLS(s)) {
|
|
dtls1_stop_timer(s);
|
|
}
|
|
return SUB_STATE_FINISHED;
|
|
|
|
case MSG_PROCESS_CONTINUE_PROCESSING:
|
|
st->read_state = READ_STATE_POST_PROCESS;
|
|
st->read_state_work = WORK_MORE_A;
|
|
break;
|
|
|
|
default:
|
|
st->read_state = READ_STATE_HEADER;
|
|
break;
|
|
}
|
|
break;
|
|
|
|
case READ_STATE_POST_PROCESS:
|
|
st->read_state_work = post_process_message(s, st->read_state_work);
|
|
switch (st->read_state_work) {
|
|
case WORK_ERROR:
|
|
check_fatal(s, SSL_F_READ_STATE_MACHINE);
|
|
/* Fall through */
|
|
case WORK_MORE_A:
|
|
case WORK_MORE_B:
|
|
case WORK_MORE_C:
|
|
return SUB_STATE_ERROR;
|
|
|
|
case WORK_FINISHED_CONTINUE:
|
|
st->read_state = READ_STATE_HEADER;
|
|
break;
|
|
|
|
case WORK_FINISHED_STOP:
|
|
if (SSL_IS_DTLS(s)) {
|
|
dtls1_stop_timer(s);
|
|
}
|
|
return SUB_STATE_FINISHED;
|
|
}
|
|
break;
|
|
|
|
default:
|
|
/* Shouldn't happen */
|
|
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_READ_STATE_MACHINE,
|
|
ERR_R_INTERNAL_ERROR);
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Send a previously constructed message to the peer.
|
|
*/
|
|
static int statem_do_write(SSL *s)
|
|
{
|
|
OSSL_STATEM *st = &s->statem;
|
|
|
|
if (st->hand_state == TLS_ST_CW_CHANGE
|
|
|| st->hand_state == TLS_ST_SW_CHANGE) {
|
|
if (SSL_IS_DTLS(s))
|
|
return dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
|
|
else
|
|
return ssl3_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC);
|
|
} else {
|
|
return ssl_do_write(s);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Initialise the MSG_FLOW_WRITING sub-state machine
|
|
*/
|
|
static void init_write_state_machine(SSL *s)
|
|
{
|
|
OSSL_STATEM *st = &s->statem;
|
|
|
|
st->write_state = WRITE_STATE_TRANSITION;
|
|
}
|
|
|
|
/*
|
|
* This function implements the sub-state machine when the message flow is in
|
|
* MSG_FLOW_WRITING. The valid sub-states and transitions are:
|
|
*
|
|
* +-> WRITE_STATE_TRANSITION ------> [SUB_STATE_FINISHED]
|
|
* | |
|
|
* | v
|
|
* | WRITE_STATE_PRE_WORK -----> [SUB_STATE_END_HANDSHAKE]
|
|
* | |
|
|
* | v
|
|
* | WRITE_STATE_SEND
|
|
* | |
|
|
* | v
|
|
* | WRITE_STATE_POST_WORK
|
|
* | |
|
|
* +-------------+
|
|
*
|
|
* WRITE_STATE_TRANSITION transitions the state of the handshake state machine
|
|
|
|
* WRITE_STATE_PRE_WORK performs any work necessary to prepare the later
|
|
* sending of the message. This could result in an NBIO event occurring in
|
|
* which case control returns to the calling application. When this function
|
|
* is recalled we will resume in the same state where we left off.
|
|
*
|
|
* WRITE_STATE_SEND sends the message and performs any work to be done after
|
|
* sending.
|
|
*
|
|
* WRITE_STATE_POST_WORK performs any work necessary after the sending of the
|
|
* message has been completed. As for WRITE_STATE_PRE_WORK this could also
|
|
* result in an NBIO event.
|
|
*/
|
|
static SUB_STATE_RETURN write_state_machine(SSL *s)
|
|
{
|
|
OSSL_STATEM *st = &s->statem;
|
|
int ret;
|
|
WRITE_TRAN(*transition) (SSL *s);
|
|
WORK_STATE(*pre_work) (SSL *s, WORK_STATE wst);
|
|
WORK_STATE(*post_work) (SSL *s, WORK_STATE wst);
|
|
int (*get_construct_message_f) (SSL *s, WPACKET *pkt,
|
|
int (**confunc) (SSL *s, WPACKET *pkt),
|
|
int *mt);
|
|
void (*cb) (const SSL *ssl, int type, int val) = NULL;
|
|
int (*confunc) (SSL *s, WPACKET *pkt);
|
|
int mt;
|
|
WPACKET pkt;
|
|
|
|
cb = get_callback(s);
|
|
|
|
if (s->server) {
|
|
transition = ossl_statem_server_write_transition;
|
|
pre_work = ossl_statem_server_pre_work;
|
|
post_work = ossl_statem_server_post_work;
|
|
get_construct_message_f = ossl_statem_server_construct_message;
|
|
} else {
|
|
transition = ossl_statem_client_write_transition;
|
|
pre_work = ossl_statem_client_pre_work;
|
|
post_work = ossl_statem_client_post_work;
|
|
get_construct_message_f = ossl_statem_client_construct_message;
|
|
}
|
|
|
|
while (1) {
|
|
switch (st->write_state) {
|
|
case WRITE_STATE_TRANSITION:
|
|
if (cb != NULL) {
|
|
/* Notify callback of an impending state change */
|
|
if (s->server)
|
|
cb(s, SSL_CB_ACCEPT_LOOP, 1);
|
|
else
|
|
cb(s, SSL_CB_CONNECT_LOOP, 1);
|
|
}
|
|
switch (transition(s)) {
|
|
case WRITE_TRAN_CONTINUE:
|
|
st->write_state = WRITE_STATE_PRE_WORK;
|
|
st->write_state_work = WORK_MORE_A;
|
|
break;
|
|
|
|
case WRITE_TRAN_FINISHED:
|
|
return SUB_STATE_FINISHED;
|
|
break;
|
|
|
|
case WRITE_TRAN_ERROR:
|
|
check_fatal(s, SSL_F_WRITE_STATE_MACHINE);
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
break;
|
|
|
|
case WRITE_STATE_PRE_WORK:
|
|
switch (st->write_state_work = pre_work(s, st->write_state_work)) {
|
|
case WORK_ERROR:
|
|
check_fatal(s, SSL_F_WRITE_STATE_MACHINE);
|
|
/* Fall through */
|
|
case WORK_MORE_A:
|
|
case WORK_MORE_B:
|
|
case WORK_MORE_C:
|
|
return SUB_STATE_ERROR;
|
|
|
|
case WORK_FINISHED_CONTINUE:
|
|
st->write_state = WRITE_STATE_SEND;
|
|
break;
|
|
|
|
case WORK_FINISHED_STOP:
|
|
return SUB_STATE_END_HANDSHAKE;
|
|
}
|
|
if (!get_construct_message_f(s, &pkt, &confunc, &mt)) {
|
|
/* SSLfatal() already called */
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
if (mt == SSL3_MT_DUMMY) {
|
|
/* Skip construction and sending. This isn't a "real" state */
|
|
st->write_state = WRITE_STATE_POST_WORK;
|
|
st->write_state_work = WORK_MORE_A;
|
|
break;
|
|
}
|
|
if (!WPACKET_init(&pkt, s->init_buf)
|
|
|| !ssl_set_handshake_header(s, &pkt, mt)) {
|
|
WPACKET_cleanup(&pkt);
|
|
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_WRITE_STATE_MACHINE,
|
|
ERR_R_INTERNAL_ERROR);
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
if (confunc != NULL && !confunc(s, &pkt)) {
|
|
WPACKET_cleanup(&pkt);
|
|
check_fatal(s, SSL_F_WRITE_STATE_MACHINE);
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
if (!ssl_close_construct_packet(s, &pkt, mt)
|
|
|| !WPACKET_finish(&pkt)) {
|
|
WPACKET_cleanup(&pkt);
|
|
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_WRITE_STATE_MACHINE,
|
|
ERR_R_INTERNAL_ERROR);
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
|
|
/* Fall through */
|
|
|
|
case WRITE_STATE_SEND:
|
|
if (SSL_IS_DTLS(s) && st->use_timer) {
|
|
dtls1_start_timer(s);
|
|
}
|
|
ret = statem_do_write(s);
|
|
if (ret <= 0) {
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
st->write_state = WRITE_STATE_POST_WORK;
|
|
st->write_state_work = WORK_MORE_A;
|
|
/* Fall through */
|
|
|
|
case WRITE_STATE_POST_WORK:
|
|
switch (st->write_state_work = post_work(s, st->write_state_work)) {
|
|
case WORK_ERROR:
|
|
check_fatal(s, SSL_F_WRITE_STATE_MACHINE);
|
|
/* Fall through */
|
|
case WORK_MORE_A:
|
|
case WORK_MORE_B:
|
|
case WORK_MORE_C:
|
|
return SUB_STATE_ERROR;
|
|
|
|
case WORK_FINISHED_CONTINUE:
|
|
st->write_state = WRITE_STATE_TRANSITION;
|
|
break;
|
|
|
|
case WORK_FINISHED_STOP:
|
|
return SUB_STATE_END_HANDSHAKE;
|
|
}
|
|
break;
|
|
|
|
default:
|
|
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_WRITE_STATE_MACHINE,
|
|
ERR_R_INTERNAL_ERROR);
|
|
return SUB_STATE_ERROR;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Flush the write BIO
|
|
*/
|
|
int statem_flush(SSL *s)
|
|
{
|
|
s->rwstate = SSL_WRITING;
|
|
if (BIO_flush(s->wbio) <= 0) {
|
|
return 0;
|
|
}
|
|
s->rwstate = SSL_NOTHING;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Called by the record layer to determine whether application data is
|
|
* allowed to be received in the current handshake state or not.
|
|
*
|
|
* Return values are:
|
|
* 1: Yes (application data allowed)
|
|
* 0: No (application data not allowed)
|
|
*/
|
|
int ossl_statem_app_data_allowed(SSL *s)
|
|
{
|
|
OSSL_STATEM *st = &s->statem;
|
|
|
|
if (st->state == MSG_FLOW_UNINITED)
|
|
return 0;
|
|
|
|
if (!s->s3->in_read_app_data || (s->s3->total_renegotiations == 0))
|
|
return 0;
|
|
|
|
if (s->server) {
|
|
/*
|
|
* If we're a server and we haven't got as far as writing our
|
|
* ServerHello yet then we allow app data
|
|
*/
|
|
if (st->hand_state == TLS_ST_BEFORE
|
|
|| st->hand_state == TLS_ST_SR_CLNT_HELLO)
|
|
return 1;
|
|
} else {
|
|
/*
|
|
* If we're a client and we haven't read the ServerHello yet then we
|
|
* allow app data
|
|
*/
|
|
if (st->hand_state == TLS_ST_CW_CLNT_HELLO)
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This function returns 1 if TLS exporter is ready to export keying
|
|
* material, or 0 if otherwise.
|
|
*/
|
|
int ossl_statem_export_allowed(SSL *s)
|
|
{
|
|
return s->s3->previous_server_finished_len != 0
|
|
&& s->statem.hand_state != TLS_ST_SW_FINISHED;
|
|
}
|
|
|
|
/*
|
|
* Return 1 if early TLS exporter is ready to export keying material,
|
|
* or 0 if otherwise.
|
|
*/
|
|
int ossl_statem_export_early_allowed(SSL *s)
|
|
{
|
|
/*
|
|
* The early exporter secret is only present on the server if we
|
|
* have accepted early_data. It is present on the client as long
|
|
* as we have sent early_data.
|
|
*/
|
|
return s->ext.early_data == SSL_EARLY_DATA_ACCEPTED
|
|
|| (!s->server && s->ext.early_data != SSL_EARLY_DATA_NOT_SENT);
|
|
}
|