diff options
Diffstat (limited to 'ssl/statem/statem.c')
| -rw-r--r-- | ssl/statem/statem.c | 2241 |
1 files changed, 2241 insertions, 0 deletions
diff --git a/ssl/statem/statem.c b/ssl/statem/statem.c new file mode 100644 index 0000000000..7e4f524ddc --- /dev/null +++ b/ssl/statem/statem.c @@ -0,0 +1,2241 @@ +/* ssl/statem/statem.c */ +/* + * Written by Matt Caswell for the OpenSSL project. + */ +/* ==================================================================== + * Copyright (c) 1998-2015 The OpenSSL Project. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * 3. All advertising materials mentioning features or use of this + * software must display the following acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" + * + * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to + * endorse or promote products derived from this software without + * prior written permission. For written permission, please contact + * openssl-core@openssl.org. + * + * 5. Products derived from this software may not be called "OpenSSL" + * nor may "OpenSSL" appear in their names without prior written + * permission of the OpenSSL Project. + * + * 6. Redistributions of any form whatsoever must retain the following + * acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit (http://www.openssl.org/)" + * + * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY + * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR + * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + * ==================================================================== + * + * This product includes cryptographic software written by Eric Young + * (eay@cryptsoft.com). This product includes software written by Tim + * Hudson (tjh@cryptsoft.com). + * + */ + +#include <openssl/rand.h> +#include "../ssl_locl.h" + +/* + * This file implements the SSL/TLS/DTLS state machines. + * + * There are two primary state machines: + * + * 1) Message flow state machine + * 2) Handshake state machine + * + * The Message flow state machine controls the reading and sending of messages + * including handling of non-blocking IO events, flushing of the underlying + * write BIO, handling unexpected messages, etc. It is itself broken into two + * separate sub-state machines which control reading and writing respectively. + * + * The Handshake state machine keeps track of the current SSL/TLS handshake + * state. Transitions of the handshake state are the result of events that + * occur within the Message flow state machine. + * + * Overall it looks like this: + * + * --------------------------------------------- ------------------- + * | | | | + * | Message flow state machine | | | + * | | | | + * | -------------------- -------------------- | Transition | Handshake state | + * | | MSG_FLOW_READING | | MSG_FLOW_WRITING | | Event | machine | + * | | sub-state | | sub-state | |----------->| | + * | | machine for | | machine for | | | | + * | | reading messages | | writing messages | | | | + * | -------------------- -------------------- | | | + * | | | | + * --------------------------------------------- ------------------- + * + */ + +/* Sub state machine return values */ +enum SUB_STATE_RETURN { + /* Something bad happened or NBIO */ + SUB_STATE_ERROR, + /* Sub state finished go to the next sub state */ + SUB_STATE_FINISHED, + /* Sub state finished and handshake was completed */ + SUB_STATE_END_HANDSHAKE +}; + +static int state_machine(SSL *s, int server); +static void init_read_state_machine(SSL *s); +static enum SUB_STATE_RETURN read_state_machine(SSL *s); +static void init_write_state_machine(SSL *s); +static enum SUB_STATE_RETURN write_state_machine(SSL *s); +static inline int cert_req_allowed(SSL *s); +static inline int key_exchange_skip_allowed(SSL *s); +static int client_read_transition(SSL *s, int mt); +static enum WRITE_TRAN client_write_transition(SSL *s); +static enum WORK_STATE client_pre_work(SSL *s, enum WORK_STATE wst); +static enum WORK_STATE client_post_work(SSL *s, enum WORK_STATE wst); +static int client_construct_message(SSL *s); +static unsigned long client_max_message_size(SSL *s); +static enum MSG_PROCESS_RETURN client_process_message(SSL *s, PACKET *pkt); +static enum WORK_STATE client_post_process_message(SSL *s, enum WORK_STATE wst); +static int server_read_transition(SSL *s, int mt); +static inline int send_server_key_exchange(SSL *s); +static inline int send_certificate_request(SSL *s); +static enum WRITE_TRAN server_write_transition(SSL *s); +static enum WORK_STATE server_pre_work(SSL *s, enum WORK_STATE wst); +static enum WORK_STATE server_post_work(SSL *s, enum WORK_STATE wst); +static int server_construct_message(SSL *s); +static unsigned long server_max_message_size(SSL *s); +static enum MSG_PROCESS_RETURN server_process_message(SSL *s, PACKET *pkt); +static enum WORK_STATE server_post_process_message(SSL *s, enum WORK_STATE wst); + + +enum HANDSHAKE_STATE SSL_state(const SSL *ssl) +{ + return ssl->statem.hand_state; +} + +void SSL_set_state(SSL *ssl, enum HANDSHAKE_STATE state) +{ + /* + * This function seems like a really bad idea. Should we remove it + * completely? + */ + ssl->statem.hand_state = state; +} + +int SSL_in_init(SSL *s) +{ + return s->statem.in_init; +} + +int SSL_is_init_finished(SSL *s) +{ + return !(s->statem.in_init) && (s->statem.hand_state == TLS_ST_OK); +} + +int SSL_in_before(SSL *s) +{ + /* + * Historically being "in before" meant before anything had happened. In the + * current code though we remain in the "before" state for a while after we + * have started the handshake process (e.g. as a server waiting for the + * first message to arrive). There "in before" is taken to mean "in before" + * and not started any handshake process yet. + */ + return (s->statem.hand_state == TLS_ST_BEFORE) + && (s->statem.state == MSG_FLOW_UNINITED); +} + +/* + * Clear the state machine state and reset back to MSG_FLOW_UNINITED + */ +void statem_clear(SSL *s) +{ + s->statem.state = MSG_FLOW_UNINITED; + s->statem.hand_state = TLS_ST_BEFORE; + s->statem.in_init = 1; +} + +/* + * Set the state machine up ready for a renegotiation handshake + */ +void statem_set_renegotiate(SSL *s) +{ + s->statem.state = MSG_FLOW_RENEGOTIATE; + s->statem.in_init = 1; +} + +/* + * Put the state machine into an error state. This is a permanent error for + * the current connection. + */ +void statem_set_error(SSL *s) +{ + s->statem.state = MSG_FLOW_ERROR; +} + +/* + * Discover whether the current connection is in the error state. + * + * Valid return values are: + * 1: Yes + * 0: No + */ +int statem_in_error(const SSL *s) +{ + if (s->statem.state == MSG_FLOW_ERROR) + return 1; + + return 0; +} + +void statem_set_in_init(SSL *s, int init) +{ + s->statem.in_init = init; +} + +int statem_connect(SSL *s) { + return state_machine(s, 0); +} + +int statem_accept(SSL *s) +{ + return state_machine(s, 1); +} + +/* + * The main message flow state machine. We start in the MSG_FLOW_UNINITED or + * MSG_FLOW_RENEGOTIATE state and finish in MSG_FLOW_FINISHED. Valid states and + * transitions are as follows: + * + * MSG_FLOW_UNINITED MSG_FLOW_RENEGOTIATE + * | | + * +-----------------------+ + * v + * MSG_FLOW_WRITING <---> MSG_FLOW_READING + * | + * V + * MSG_FLOW_FINISHED + * | + * V + * [SUCCESS] + * + * We may exit at any point due to an error or NBIO event. If an NBIO event + * occurs then we restart at the point we left off when we are recalled. + * MSG_FLOW_WRITING and MSG_FLOW_READING have sub-state machines associated with them. + * + * In addition to the above there is also the MSG_FLOW_ERROR state. We can move + * into that state at any point in the event that an irrecoverable error occurs. + * + * Valid return values are: + * 1: Success + * <=0: NBIO or error + */ +static int state_machine(SSL *s, int server) { + BUF_MEM *buf = NULL; + unsigned long Time = (unsigned long)time(NULL); + void (*cb) (const SSL *ssl, int type, int val) = NULL; + STATEM *st = &s->statem; + int ret = -1; + int ssret; + + if (st->state == MSG_FLOW_ERROR) { + /* Shouldn't have been called if we're already in the error state */ + return -1; + } + + RAND_add(&Time, sizeof(Time), 0); + ERR_clear_error(); + clear_sys_error(); + + if (s->info_callback != NULL) + cb = s->info_callback; + else if (s->ctx->info_callback != NULL) + cb = s->ctx->info_callback; + + s->in_handshake++; + if (!SSL_in_init(s) || SSL_in_before(s)) { + if (!SSL_clear(s)) + return -1; + } + +#ifndef OPENSSL_NO_SCTP + if (SSL_IS_DTLS(s)) { + /* + * Notify SCTP BIO socket to enter handshake mode and prevent stream + * identifier other than 0. Will be ignored if no SCTP is used. + */ + BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE, + s->in_handshake, NULL); + } +#endif + +#ifndef OPENSSL_NO_HEARTBEATS + /* + * If we're awaiting a HeartbeatResponse, pretend we already got and + * don't await it anymore, because Heartbeats don't make sense during + * handshakes anyway. + */ + if (s->tlsext_hb_pending) { + if (SSL_IS_DTLS(s)) + dtls1_stop_timer(s); + s->tlsext_hb_pending = 0; + s->tlsext_hb_seq++; + } +#endif + + /* Initialise state machine */ + + if (st->state == MSG_FLOW_RENEGOTIATE) { + s->renegotiate = 1; + if (!server) + s->ctx->stats.sess_connect_renegotiate++; + } + + if (st->state == MSG_FLOW_UNINITED || st->state == MSG_FLOW_RENEGOTIATE) { + if (st->state == MSG_FLOW_UNINITED) { + st->hand_state = TLS_ST_BEFORE; + } + + s->server = server; + if (cb != NULL) + cb(s, SSL_CB_HANDSHAKE_START, 1); + + if (SSL_IS_DTLS(s)) { + if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00) && + (server + || (s->version & 0xff00) != (DTLS1_BAD_VER & 0xff00))) { + SSLerr(SSL_F_STATE_MACHINE, ERR_R_INTERNAL_ERROR); + goto end; + } + } else { + if ((s->version >> 8) != SSL3_VERSION_MAJOR + && s->version != TLS_ANY_VERSION) { + SSLerr(SSL_F_STATE_MACHINE, ERR_R_INTERNAL_ERROR); + goto end; + } + } + + if (!SSL_IS_DTLS(s)) { + if (s->version != TLS_ANY_VERSION && + !ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) { + SSLerr(SSL_F_STATE_MACHINE, SSL_R_VERSION_TOO_LOW); + goto end; + } + } + + if (s->init_buf == NULL) { + if ((buf = BUF_MEM_new()) == NULL) { + goto end; + } + if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) { + goto end; + } + s->init_buf = buf; + buf = NULL; + } + + if (!ssl3_setup_buffers(s)) { + goto end; + } + s->init_num = 0; + + /* + * Should have been reset by tls_process_finished, too. + */ + s->s3->change_cipher_spec = 0; + + if (!server || st->state != MSG_FLOW_RENEGOTIATE) { + /* + * 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, server ? 1 : 0)) { + goto end; + } + + ssl3_init_finished_mac(s); + } + + if (server) { + if (st->state != MSG_FLOW_RENEGOTIATE) { + s->ctx->stats.sess_accept++; + } else if (!s->s3->send_connection_binding && + !(s->options & + SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)) { + /* + * Server attempting to renegotiate with client that doesn't + * support secure renegotiation. + */ + SSLerr(SSL_F_STATE_MACHINE, + SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED); + ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE); + statem_set_error(s); + goto end; + } else { + /* + * s->state == SSL_ST_RENEGOTIATE, we will just send a + * HelloRequest + */ + s->ctx->stats.sess_accept_renegotiate++; + } + } else { + s->ctx->stats.sess_connect++; + + /* mark client_random uninitialized */ + memset(s->s3->client_random, 0, sizeof(s->s3->client_random)); + s->hit = 0; + + s->s3->tmp.cert_request = 0; + + if (SSL_IS_DTLS(s)) { + st->use_timer = 1; + } + } + + st->state = MSG_FLOW_WRITING; + init_write_state_machine(s); + st->read_state_first_init = 1; + } + + 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 */ + statem_set_error(s); + goto end; + } + } + + st->state = MSG_FLOW_UNINITED; + ret = 1; + + end: + s->in_handshake--; + +#ifndef OPENSSL_NO_SCTP + if (SSL_IS_DTLS(s)) { + /* + * Notify SCTP BIO socket to leave handshake mode and allow stream + * identifier other than 0. Will be ignored if no SCTP is used. + */ + BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE, + s->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) +{ + STATEM *st = &s->statem; + + st->read_state = READ_STATE_HEADER; +} + +/* + * 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 occuring 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 enum SUB_STATE_RETURN read_state_machine(SSL *s) { + STATEM *st = &s->statem; + int ret, mt; + unsigned long len; + int (*transition)(SSL *s, int mt); + PACKET pkt; + enum MSG_PROCESS_RETURN (*process_message)(SSL *s, PACKET *pkt); + enum WORK_STATE (*post_process_message)(SSL *s, enum WORK_STATE wst); + unsigned long (*max_message_size)(SSL *s); + void (*cb) (const SSL *ssl, int type, int val) = NULL; + + if (s->info_callback != NULL) + cb = s->info_callback; + else if (s->ctx->info_callback != NULL) + cb = s->ctx->info_callback; + + if(s->server) { + transition = server_read_transition; + process_message = server_process_message; + max_message_size = server_max_message_size; + post_process_message = server_post_process_message; + } else { + transition = client_read_transition; + process_message = client_process_message; + max_message_size = client_max_message_size; + post_process_message = 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: + s->init_num = 0; + /* 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)) { + ssl3_send_alert(s, SSL3_AL_FATAL, SSL3_AD_UNEXPECTED_MESSAGE); + SSLerr(SSL_F_READ_STATE_MACHINE, SSL_R_UNEXPECTED_MESSAGE); + return SUB_STATE_ERROR; + } + + if (s->s3->tmp.message_size > max_message_size(s)) { + ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); + SSLerr(SSL_F_READ_STATE_MACHINE, SSL_R_EXCESSIVE_MESSAGE_SIZE); + 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)) { + ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); + SSLerr(SSL_F_READ_STATE_MACHINE, ERR_R_INTERNAL_ERROR); + return SUB_STATE_ERROR; + } + ret = process_message(s, &pkt); + if (ret == MSG_PROCESS_ERROR) { + return SUB_STATE_ERROR; + } + + if (ret == MSG_PROCESS_FINISHED_READING) { + if (SSL_IS_DTLS(s)) { + dtls1_stop_timer(s); + } + return SUB_STATE_FINISHED; + } + + if (ret == MSG_PROCESS_CONTINUE_PROCESSING) { + st->read_state = READ_STATE_POST_PROCESS; + st->read_state_work = WORK_MORE_A; + } else { + st->read_state = READ_STATE_HEADER; + } + break; + + case READ_STATE_POST_PROCESS: + st->read_state_work = post_process_message(s, st->read_state_work); + switch(st->read_state_work) { + default: + 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 */ + ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR); + SSLerr(SSL_F_READ_STATE_MACHINE, ERR_R_INTERNAL_ERROR); + statem_set_error(s); + return SUB_STATE_ERROR; + } + } +} + +/* + * Send a previously constructed message to the peer. + */ +static int statem_do_write(SSL *s) +{ + 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) +{ + 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 occuring 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 enum SUB_STATE_RETURN write_state_machine(SSL *s) +{ + STATEM *st = &s->statem; + int ret; + enum WRITE_TRAN (*transition)(SSL *s); + enum WORK_STATE (*pre_work)(SSL *s, enum WORK_STATE wst); + enum WORK_STATE (*post_work)(SSL *s, enum WORK_STATE wst); + int (*construct_message)(SSL *s); + void (*cb) (const SSL *ssl, int type, int val) = NULL; + + if (s->info_callback != NULL) + cb = s->info_callback; + else if (s->ctx->info_callback != NULL) + cb = s->ctx->info_callback; + + if(s->server) { + transition = server_write_transition; + pre_work = server_pre_work; + post_work = server_post_work; + construct_message = server_construct_message; + } else { + transition = client_write_transition; + pre_work = client_pre_work; + post_work = client_post_work; + construct_message = 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; + + default: + return SUB_STATE_ERROR; + } + break; + + case WRITE_STATE_PRE_WORK: + switch(st->write_state_work = pre_work(s, st->write_state_work)) { + default: + 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(construct_message(s) == 0) + 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)) { + default: + 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: + return SUB_STATE_ERROR; + } + } +} + +/* + * Flush the write BIO + */ +static 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 sent in the current handshake state or not. + * + * Return values are: + * 1: Yes (application data allowed) + * 0: No (application data not allowed) + */ +int statem_app_data_allowed(SSL *s) +{ + STATEM *st = &s->statem; + + if (st->state == MSG_FLOW_UNINITED || st->state == MSG_FLOW_RENEGOTIATE) + 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; +} + + +#ifndef OPENSSL_NO_SCTP +/* + * Set flag used by SCTP to determine whether we are in the read sock state + */ +void statem_set_sctp_read_sock(SSL *s, int read_sock) +{ + s->statem.in_sctp_read_sock = read_sock; +} + +/* + * Called by the record layer to determine whether we are in the read sock + * state or not. + * + * Return values are: + * 1: Yes (we are in the read sock state) + * 0: No (we are not in the read sock state) + */ +int statem_in_sctp_read_sock(SSL *s) +{ + return s->statem.in_sctp_read_sock; +} +#endif + +/* + * Is a CertificateRequest message allowed at the moment or not? + * + * Return values are: + * 1: Yes + * 0: No + */ +static inline int cert_req_allowed(SSL *s) +{ + /* TLS does not like anon-DH with client cert */ + if (s->version > SSL3_VERSION + && (s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)) + return 0; + + return 1; +} + +/* + * Are we allowed to skip the ServerKeyExchange message? + * + * Return values are: + * 1: Yes + * 0: No + */ +static inline int key_exchange_skip_allowed(SSL *s) +{ + long alg_k = s->s3->tmp.new_cipher->algorithm_mkey; + + /* + * Can't skip server key exchange if this is an ephemeral + * ciphersuite. + */ + if (alg_k & (SSL_kDHE | SSL_kECDHE)) { + return 0; + } + + return 1; +} + +/* + * client_read_transition() encapsulates the logic for the allowed handshake + * state transitions when the client is reading messages from the server. The + * message type that the server has sent is provided in |mt|. The current state + * is in |s->statem.hand_state|. + * + * Return values are: + * 1: Success (transition allowed) + * 0: Error (transition not allowed) + */ +static int client_read_transition(SSL *s, int mt) +{ + STATEM *st = &s->statem; + + switch(st->hand_state) { + case TLS_ST_CW_CLNT_HELLO: + if (mt == SSL3_MT_SERVER_HELLO) { + st->hand_state = TLS_ST_CR_SRVR_HELLO; + return 1; + } + + if (SSL_IS_DTLS(s)) { + if (mt == DTLS1_MT_HELLO_VERIFY_REQUEST) { + st->hand_state = DTLS_ST_CR_HELLO_VERIFY_REQUEST; + return 1; + } + } + break; + + case TLS_ST_CR_SRVR_HELLO: + if (s->hit) { + if (s->tlsext_ticket_expected) { + if (mt == SSL3_MT_NEWSESSION_TICKET) { + st->hand_state = TLS_ST_CR_SESSION_TICKET; + return 1; + } + } else if (mt == SSL3_MT_CHANGE_CIPHER_SPEC) { + st->hand_state = TLS_ST_CR_CHANGE; + return 1; + } + } else { + if (SSL_IS_DTLS(s) && mt == DTLS1_MT_HELLO_VERIFY_REQUEST) { + st->hand_state = DTLS_ST_CR_HELLO_VERIFY_REQUEST; + return 1; + } else if (!(s->s3->tmp.new_cipher->algorithm_auth + & (SSL_aNULL | SSL_aSRP | SSL_aPSK))) { + if (mt == SSL3_MT_CERTIFICATE) { + st->hand_state = TLS_ST_CR_CERT; + return 1; + } + } else { + if (mt == SSL3_MT_SERVER_KEY_EXCHANGE) { + st->hand_state = TLS_ST_CR_KEY_EXCH; + return 1; + } else if (key_exchange_skip_allowed(s)) { + if (mt == SSL3_MT_CERTIFICATE_REQUEST + && cert_req_allowed(s)) { + st->hand_state = TLS_ST_CR_CERT_REQ; + return 1; + } else if (mt == SSL3_MT_SERVER_DONE) { + st->hand_state = TLS_ST_CR_SRVR_DONE; + return 1; + } + } + } + } + break; + + case TLS_ST_CR_CERT: + if (s->tlsext_status_expected) { + if (mt == SSL3_MT_CERTIFICATE_STATUS) { + st->hand_state = TLS_ST_CR_CERT_STATUS; + return 1; + } + } else { + if (mt == SSL3_MT_SERVER_KEY_EXCHANGE) { + st->hand_state = TLS_ST_CR_KEY_EXCH; + return 1; + } else if (key_exchange_skip_allowed(s)) { + if (mt == SSL3_MT_CERTIFICATE_REQUEST && cert_req_allowed(s)) { + st->hand_state = TLS_ST_CR_CERT_REQ; + return 1; + } else if (mt == SSL3_MT_SERVER_DONE) { + st->hand_state = TLS_ST_CR_SRVR_DONE; + return 1; + } + } + } + break; + + case TLS_ST_CR_CERT_STATUS: + if (mt == SSL3_MT_SERVER_KEY_EXCHANGE) { + st->hand_state = TLS_ST_CR_KEY_EXCH; + return 1; + } else if (key_exchange_skip_allowed(s)) { + if (mt == SSL3_MT_CERTIFICATE_REQUEST && cert_req_allowed(s)) { + st->hand_state = TLS_ST_CR_CERT_REQ; + return 1; + } else if (mt == SSL3_MT_SERVER_DONE) { + st->hand_state = TLS_ST_CR_SRVR_DONE; + return 1; + } + } + break; + + case TLS_ST_CR_KEY_EXCH: + if (mt == SSL3_MT_CERTIFICATE_REQUEST && cert_req_allowed(s)) { + st->hand_state = TLS_ST_CR_CERT_REQ; + |