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boringssl/ssl/d1_both.c
David Benjamin 0d56f888c3 Switch s to ssl everywhere. 
That we're half and half is really confusing.

Change-Id: I1c2632682e8a3e63d01dada8e0eb3b735ff709ce
Reviewed-on: https://boringssl-review.googlesource.com/6785
Reviewed-by: Adam Langley <agl@google.com>
2015-12-22 23:28:22 +00:00

882 lines
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/*
* DTLS implementation written by Nagendra Modadugu
* (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
*/
/* ====================================================================
* Copyright (c) 1998-2005 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).
*
*/
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* 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 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 acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS 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 AUTHOR OR 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.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#include <openssl/ssl.h>
#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <openssl/buf.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include <openssl/rand.h>
#include <openssl/x509.h>
#include "internal.h"
/* TODO(davidben): 28 comes from the size of IP + UDP header. Is this reasonable
* for these values? Notably, why is kMinMTU a function of the transport
* protocol's overhead rather than, say, what's needed to hold a minimally-sized
* handshake fragment plus protocol overhead. */
/* kMinMTU is the minimum acceptable MTU value. */
static const unsigned int kMinMTU = 256 - 28;
/* kDefaultMTU is the default MTU value to use if neither the user nor
* the underlying BIO supplies one. */
static const unsigned int kDefaultMTU = 1500 - 28;
/* kMaxHandshakeBuffer is the maximum number of handshake messages ahead of the
* current one to buffer. */
static const unsigned int kHandshakeBufferSize = 10;
static hm_fragment *dtls1_hm_fragment_new(size_t frag_len, int reassembly) {
hm_fragment *frag = OPENSSL_malloc(sizeof(hm_fragment));
if (frag == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return NULL;
}
memset(frag, 0, sizeof(hm_fragment));
/* If the handshake message is empty, |frag->fragment| and |frag->reassembly|
* are NULL. */
if (frag_len > 0) {
frag->fragment = OPENSSL_malloc(frag_len);
if (frag->fragment == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
if (reassembly) {
/* Initialize reassembly bitmask. */
if (frag_len + 7 < frag_len) {
OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
goto err;
}
size_t bitmask_len = (frag_len + 7) / 8;
frag->reassembly = OPENSSL_malloc(bitmask_len);
if (frag->reassembly == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
memset(frag->reassembly, 0, bitmask_len);
}
}
return frag;
err:
dtls1_hm_fragment_free(frag);
return NULL;
}
void dtls1_hm_fragment_free(hm_fragment *frag) {
if (frag == NULL) {
return;
}
OPENSSL_free(frag->fragment);
OPENSSL_free(frag->reassembly);
OPENSSL_free(frag);
}
#if !defined(inline)
#define inline __inline
#endif
/* bit_range returns a |uint8_t| with bits |start|, inclusive, to |end|,
* exclusive, set. */
static inline uint8_t bit_range(size_t start, size_t end) {
return (uint8_t)(~((1u << start) - 1) & ((1u << end) - 1));
}
/* dtls1_hm_fragment_mark marks bytes |start|, inclusive, to |end|, exclusive,
* as received in |frag|. If |frag| becomes complete, it clears
* |frag->reassembly|. The range must be within the bounds of |frag|'s message
* and |frag->reassembly| must not be NULL. */
static void dtls1_hm_fragment_mark(hm_fragment *frag, size_t start,
size_t end) {
size_t i;
size_t msg_len = frag->msg_header.msg_len;
if (frag->reassembly == NULL || start > end || end > msg_len) {
assert(0);
return;
}
/* A zero-length message will never have a pending reassembly. */
assert(msg_len > 0);
if ((start >> 3) == (end >> 3)) {
frag->reassembly[start >> 3] |= bit_range(start & 7, end & 7);
} else {
frag->reassembly[start >> 3] |= bit_range(start & 7, 8);
for (i = (start >> 3) + 1; i < (end >> 3); i++) {
frag->reassembly[i] = 0xff;
}
if ((end & 7) != 0) {
frag->reassembly[end >> 3] |= bit_range(0, end & 7);
}
}
/* Check if the fragment is complete. */
for (i = 0; i < (msg_len >> 3); i++) {
if (frag->reassembly[i] != 0xff) {
return;
}
}
if ((msg_len & 7) != 0 &&
frag->reassembly[msg_len >> 3] != bit_range(0, msg_len & 7)) {
return;
}
OPENSSL_free(frag->reassembly);
frag->reassembly = NULL;
}
static void dtls1_update_mtu(SSL *ssl) {
/* TODO(davidben): What is this code doing and do we need it? */
if (ssl->d1->mtu < dtls1_min_mtu() &&
!(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) {
long mtu = BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
if (mtu >= 0 && mtu <= (1 << 30) && (unsigned)mtu >= dtls1_min_mtu()) {
ssl->d1->mtu = (unsigned)mtu;
} else {
ssl->d1->mtu = kDefaultMTU;
BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_SET_MTU, ssl->d1->mtu, NULL);
}
}
/* The MTU should be above the minimum now. */
assert(ssl->d1->mtu >= dtls1_min_mtu());
}
/* dtls1_max_record_size returns the maximum record body length that may be
* written without exceeding the MTU. It accounts for any buffering installed on
* the write BIO. If no record may be written, it returns zero. */
static size_t dtls1_max_record_size(SSL *ssl) {
size_t ret = ssl->d1->mtu;
size_t overhead = ssl_max_seal_overhead(ssl);
if (ret <= overhead) {
return 0;
}
ret -= overhead;
size_t pending = BIO_wpending(SSL_get_wbio(ssl));
if (ret <= pending) {
return 0;
}
ret -= pending;
return ret;
}
static int dtls1_write_change_cipher_spec(SSL *ssl,
enum dtls1_use_epoch_t use_epoch) {
dtls1_update_mtu(ssl);
/* During the handshake, wbio is buffered to pack messages together. Flush the
* buffer if the ChangeCipherSpec would not fit in a packet. */
if (dtls1_max_record_size(ssl) == 0) {
ssl->rwstate = SSL_WRITING;
int ret = BIO_flush(SSL_get_wbio(ssl));
if (ret <= 0) {
return ret;
}
ssl->rwstate = SSL_NOTHING;
}
static const uint8_t kChangeCipherSpec[1] = {SSL3_MT_CCS};
int ret =
dtls1_write_bytes(ssl, SSL3_RT_CHANGE_CIPHER_SPEC, kChangeCipherSpec,
sizeof(kChangeCipherSpec), use_epoch);
if (ret <= 0) {
return ret;
}
if (ssl->msg_callback != NULL) {
ssl->msg_callback(1 /* write */, ssl->version, SSL3_RT_CHANGE_CIPHER_SPEC,
kChangeCipherSpec, sizeof(kChangeCipherSpec), ssl,
ssl->msg_callback_arg);
}
return 1;
}
int dtls1_do_handshake_write(SSL *ssl, enum dtls1_use_epoch_t use_epoch) {
dtls1_update_mtu(ssl);
int ret = -1;
CBB cbb;
CBB_zero(&cbb);
/* Allocate a temporary buffer to hold the message fragments to avoid
* clobbering the message. */
uint8_t *buf = OPENSSL_malloc(ssl->d1->mtu);
if (buf == NULL) {
goto err;
}
/* Consume the message header. Fragments will have different headers
* prepended. */
if (ssl->init_off == 0) {
ssl->init_off += DTLS1_HM_HEADER_LENGTH;
ssl->init_num -= DTLS1_HM_HEADER_LENGTH;
}
assert(ssl->init_off >= DTLS1_HM_HEADER_LENGTH);
do {
/* During the handshake, wbio is buffered to pack messages together. Flush
* the buffer if there isn't enough room to make progress. */
if (dtls1_max_record_size(ssl) < DTLS1_HM_HEADER_LENGTH + 1) {
ssl->rwstate = SSL_WRITING;
int flush_ret = BIO_flush(SSL_get_wbio(ssl));
if (flush_ret <= 0) {
ret = flush_ret;
goto err;
}
ssl->rwstate = SSL_NOTHING;
assert(BIO_wpending(SSL_get_wbio(ssl)) == 0);
}
size_t todo = dtls1_max_record_size(ssl);
if (todo < DTLS1_HM_HEADER_LENGTH + 1) {
/* To make forward progress, the MTU must, at minimum, fit the handshake
* header and one byte of handshake body. */
OPENSSL_PUT_ERROR(SSL, SSL_R_MTU_TOO_SMALL);
goto err;
}
todo -= DTLS1_HM_HEADER_LENGTH;
if (todo > (size_t)ssl->init_num) {
todo = ssl->init_num;
}
if (todo >= (1u << 24)) {
todo = (1u << 24) - 1;
}
size_t len;
if (!CBB_init_fixed(&cbb, buf, ssl->d1->mtu) ||
!CBB_add_u8(&cbb, ssl->d1->w_msg_hdr.type) ||
!CBB_add_u24(&cbb, ssl->d1->w_msg_hdr.msg_len) ||
!CBB_add_u16(&cbb, ssl->d1->w_msg_hdr.seq) ||
!CBB_add_u24(&cbb, ssl->init_off - DTLS1_HM_HEADER_LENGTH) ||
!CBB_add_u24(&cbb, todo) ||
!CBB_add_bytes(
&cbb, (const uint8_t *)ssl->init_buf->data + ssl->init_off, todo) ||
!CBB_finish(&cbb, NULL, &len)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
goto err;
}
int write_ret = dtls1_write_bytes(ssl, SSL3_RT_HANDSHAKE, buf, len,
use_epoch);
if (write_ret <= 0) {
ret = write_ret;
goto err;
}
ssl->init_off += todo;
ssl->init_num -= todo;
} while (ssl->init_num > 0);
if (ssl->msg_callback != NULL) {
ssl->msg_callback(
1 /* write */, ssl->version, SSL3_RT_HANDSHAKE, ssl->init_buf->data,
(size_t)(ssl->init_off + ssl->init_num), ssl, ssl->msg_callback_arg);
}
ssl->init_off = 0;
ssl->init_num = 0;
ret = 1;
err:
CBB_cleanup(&cbb);
OPENSSL_free(buf);
return ret;
}
/* dtls1_is_next_message_complete returns one if the next handshake message is
* complete and zero otherwise. */
static int dtls1_is_next_message_complete(SSL *ssl) {
pitem *item = pqueue_peek(ssl->d1->buffered_messages);
if (item == NULL) {
return 0;
}
hm_fragment *frag = (hm_fragment *)item->data;
assert(ssl->d1->handshake_read_seq <= frag->msg_header.seq);
return ssl->d1->handshake_read_seq == frag->msg_header.seq &&
frag->reassembly == NULL;
}
/* dtls1_discard_fragment_body discards a handshake fragment body of length
* |frag_len|. It returns one on success and zero on error.
*
* TODO(davidben): This function will go away when ssl_read_bytes is gone from
* the DTLS side. */
static int dtls1_discard_fragment_body(SSL *ssl, size_t frag_len) {
uint8_t discard[256];
while (frag_len > 0) {
size_t chunk = frag_len < sizeof(discard) ? frag_len : sizeof(discard);
int ret = dtls1_read_bytes(ssl, SSL3_RT_HANDSHAKE, discard, chunk, 0);
if (ret != (int) chunk) {
return 0;
}
frag_len -= chunk;
}
return 1;
}
/* dtls1_get_buffered_message returns the buffered message corresponding to
* |msg_hdr|. If none exists, it creates a new one and inserts it in the
* queue. Otherwise, it checks |msg_hdr| is consistent with the existing one. It
* returns NULL on failure. The caller does not take ownership of the result. */
static hm_fragment *dtls1_get_buffered_message(
SSL *ssl, const struct hm_header_st *msg_hdr) {
uint8_t seq64be[8];
memset(seq64be, 0, sizeof(seq64be));
seq64be[6] = (uint8_t)(msg_hdr->seq >> 8);
seq64be[7] = (uint8_t)msg_hdr->seq;
pitem *item = pqueue_find(ssl->d1->buffered_messages, seq64be);
hm_fragment *frag;
if (item == NULL) {
/* This is the first fragment from this message. */
frag = dtls1_hm_fragment_new(msg_hdr->msg_len,
1 /* reassembly buffer needed */);
if (frag == NULL) {
return NULL;
}
memcpy(&frag->msg_header, msg_hdr, sizeof(*msg_hdr));
item = pitem_new(seq64be, frag);
if (item == NULL) {
dtls1_hm_fragment_free(frag);
return NULL;
}
item = pqueue_insert(ssl->d1->buffered_messages, item);
/* |pqueue_insert| fails iff a duplicate item is inserted, but |item| cannot
* be a duplicate. */
assert(item != NULL);
} else {
frag = item->data;
assert(frag->msg_header.seq == msg_hdr->seq);
if (frag->msg_header.type != msg_hdr->type ||
frag->msg_header.msg_len != msg_hdr->msg_len) {
/* The new fragment must be compatible with the previous fragments from
* this message. */
OPENSSL_PUT_ERROR(SSL, SSL_R_FRAGMENT_MISMATCH);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return NULL;
}
}
return frag;
}
/* dtls1_max_handshake_message_len returns the maximum number of bytes
* permitted in a DTLS handshake message for |ssl|. The minimum is 16KB, but may
* be greater if the maximum certificate list size requires it. */
static size_t dtls1_max_handshake_message_len(const SSL *ssl) {
size_t max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
if (max_len < ssl->max_cert_list) {
return ssl->max_cert_list;
}
return max_len;
}
/* dtls1_process_fragment reads a handshake fragment and processes it. It
* returns one if a fragment was successfully processed and 0 or -1 on error. */
static int dtls1_process_fragment(SSL *ssl) {
/* Read handshake message header. */
uint8_t header[DTLS1_HM_HEADER_LENGTH];
int ret = dtls1_read_bytes(ssl, SSL3_RT_HANDSHAKE, header,
DTLS1_HM_HEADER_LENGTH, 0);
if (ret <= 0) {
return ret;
}
if (ret != DTLS1_HM_HEADER_LENGTH) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
/* Parse the message fragment header. */
struct hm_header_st msg_hdr;
dtls1_get_message_header(header, &msg_hdr);
/* TODO(davidben): dtls1_read_bytes is the wrong abstraction for DTLS. There
* should be no need to reach into |ssl->s3->rrec.length|. */
const size_t frag_off = msg_hdr.frag_off;
const size_t frag_len = msg_hdr.frag_len;
const size_t msg_len = msg_hdr.msg_len;
if (frag_off > msg_len || frag_off + frag_len < frag_off ||
frag_off + frag_len > msg_len ||
msg_len > dtls1_max_handshake_message_len(ssl) ||
frag_len > ssl->s3->rrec.length) {
OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESSIVE_MESSAGE_SIZE);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return -1;
}
if (msg_hdr.seq < ssl->d1->handshake_read_seq ||
msg_hdr.seq > (unsigned)ssl->d1->handshake_read_seq +
kHandshakeBufferSize) {
/* Ignore fragments from the past, or ones too far in the future. */
if (!dtls1_discard_fragment_body(ssl, frag_len)) {
return -1;
}
return 1;
}
hm_fragment *frag = dtls1_get_buffered_message(ssl, &msg_hdr);
if (frag == NULL) {
return -1;
}
assert(frag->msg_header.msg_len == msg_len);
if (frag->reassembly == NULL) {
/* The message is already assembled. */
if (!dtls1_discard_fragment_body(ssl, frag_len)) {
return -1;
}
return 1;
}
assert(msg_len > 0);
/* Read the body of the fragment. */
ret = dtls1_read_bytes(ssl, SSL3_RT_HANDSHAKE, frag->fragment + frag_off,
frag_len, 0);
if (ret != (int) frag_len) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return -1;
}
dtls1_hm_fragment_mark(frag, frag_off, frag_off + frag_len);
return 1;
}
/* dtls1_get_message reads a handshake message of message type |msg_type| (any
* if |msg_type| == -1), maximum acceptable body length |max|. Read an entire
* handshake message. Handshake messages arrive in fragments. */
long dtls1_get_message(SSL *ssl, int st1, int stn, int msg_type, long max,
enum ssl_hash_message_t hash_message, int *ok) {
pitem *item = NULL;
hm_fragment *frag = NULL;
int al;
/* s3->tmp is used to store messages that are unexpected, caused
* by the absence of an optional handshake message */
if (ssl->s3->tmp.reuse_message) {
/* A ssl_dont_hash_message call cannot be combined with reuse_message; the
* ssl_dont_hash_message would have to have been applied to the previous
* call. */
assert(hash_message == ssl_hash_message);
ssl->s3->tmp.reuse_message = 0;
if (msg_type >= 0 && ssl->s3->tmp.message_type != msg_type) {
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
*ok = 1;
ssl->init_msg = (uint8_t *)ssl->init_buf->data + DTLS1_HM_HEADER_LENGTH;
ssl->init_num = (int)ssl->s3->tmp.message_size;
return ssl->init_num;
}
/* Process fragments until one is found. */
while (!dtls1_is_next_message_complete(ssl)) {
int ret = dtls1_process_fragment(ssl);
if (ret <= 0) {
*ok = 0;
return ret;
}
}
/* Read out the next complete handshake message. */
item = pqueue_pop(ssl->d1->buffered_messages);
assert(item != NULL);
frag = (hm_fragment *)item->data;
assert(ssl->d1->handshake_read_seq == frag->msg_header.seq);
assert(frag->reassembly == NULL);
if (frag->msg_header.msg_len > (size_t)max) {
OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESSIVE_MESSAGE_SIZE);
goto err;
}
/* Reconstruct the assembled message. */
size_t len;
CBB cbb;
CBB_zero(&cbb);
if (!BUF_MEM_grow(ssl->init_buf, (size_t)frag->msg_header.msg_len +
DTLS1_HM_HEADER_LENGTH) ||
!CBB_init_fixed(&cbb, (uint8_t *)ssl->init_buf->data,
ssl->init_buf->max) ||
!CBB_add_u8(&cbb, frag->msg_header.type) ||
!CBB_add_u24(&cbb, frag->msg_header.msg_len) ||
!CBB_add_u16(&cbb, frag->msg_header.seq) ||
!CBB_add_u24(&cbb, 0 /* frag_off */) ||
!CBB_add_u24(&cbb, frag->msg_header.msg_len) ||
!CBB_add_bytes(&cbb, frag->fragment, frag->msg_header.msg_len) ||
!CBB_finish(&cbb, NULL, &len)) {
CBB_cleanup(&cbb);
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
assert(len == (size_t)frag->msg_header.msg_len + DTLS1_HM_HEADER_LENGTH);
ssl->d1->handshake_read_seq++;
/* TODO(davidben): This function has a lot of implicit outputs. Simplify the
* |ssl_get_message| API. */
ssl->s3->tmp.message_type = frag->msg_header.type;
ssl->s3->tmp.message_size = frag->msg_header.msg_len;
ssl->init_msg = (uint8_t *)ssl->init_buf->data + DTLS1_HM_HEADER_LENGTH;
ssl->init_num = frag->msg_header.msg_len;
if (msg_type >= 0 && ssl->s3->tmp.message_type != msg_type) {
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
if (hash_message == ssl_hash_message && !ssl3_hash_current_message(ssl)) {
goto err;
}
if (ssl->msg_callback) {
ssl->msg_callback(0, ssl->version, SSL3_RT_HANDSHAKE, ssl->init_buf->data,
ssl->init_num + DTLS1_HM_HEADER_LENGTH, ssl,
ssl->msg_callback_arg);
}
pitem_free(item);
dtls1_hm_fragment_free(frag);
ssl->state = stn;
*ok = 1;
return ssl->init_num;
f_err:
ssl3_send_alert(ssl, SSL3_AL_FATAL, al);
err:
pitem_free(item);
dtls1_hm_fragment_free(frag);
*ok = 0;
return -1;
}
int dtls1_read_failed(SSL *ssl, int code) {
if (code > 0) {
assert(0);
return 1;
}
if (!dtls1_is_timer_expired(ssl)) {
/* not a timeout, none of our business, let higher layers handle this. In
* fact, it's probably an error */
return code;
}
if (!SSL_in_init(ssl)) {
/* done, no need to send a retransmit */
BIO_set_flags(SSL_get_rbio(ssl), BIO_FLAGS_READ);
return code;
}
return DTLSv1_handle_timeout(ssl);
}
static uint16_t dtls1_get_queue_priority(uint16_t seq, int is_ccs) {
assert(seq * 2 >= seq);
/* The index of the retransmission queue actually is the message sequence
* number, since the queue only contains messages of a single handshake.
* However, the ChangeCipherSpec has no message sequence number and so using
* only the sequence will result in the CCS and Finished having the same
* index. To prevent this, the sequence number is multiplied by 2. In case of
* a CCS 1 is subtracted. This does not only differ CSS and Finished, it also
* maintains the order of the index (important for priority queues) and fits
* in the unsigned short variable. */
return seq * 2 - is_ccs;
}
static int dtls1_retransmit_message(SSL *ssl, hm_fragment *frag) {
/* DTLS renegotiation is unsupported, so only epochs 0 (NULL cipher) and 1
* (negotiated cipher) exist. */
assert(ssl->d1->w_epoch == 0 || ssl->d1->w_epoch == 1);
assert(frag->msg_header.epoch <= ssl->d1->w_epoch);
enum dtls1_use_epoch_t use_epoch = dtls1_use_current_epoch;
if (ssl->d1->w_epoch == 1 && frag->msg_header.epoch == 0) {
use_epoch = dtls1_use_previous_epoch;
}
/* TODO(davidben): This cannot handle non-blocking writes. */
int ret;
if (frag->msg_header.is_ccs) {
ret = dtls1_write_change_cipher_spec(ssl, use_epoch);
} else {
/* Restore the message body.
* TODO(davidben): Make this less stateful. */
memcpy(ssl->init_buf->data, frag->fragment,
frag->msg_header.msg_len + DTLS1_HM_HEADER_LENGTH);
ssl->init_num = frag->msg_header.msg_len + DTLS1_HM_HEADER_LENGTH;
dtls1_set_message_header(ssl, frag->msg_header.type,
frag->msg_header.msg_len, frag->msg_header.seq,
0, frag->msg_header.frag_len);
ret = dtls1_do_handshake_write(ssl, use_epoch);
}
/* TODO(davidben): Check return value? */
(void)BIO_flush(SSL_get_wbio(ssl));
return ret;
}
int dtls1_retransmit_buffered_messages(SSL *ssl) {
pqueue sent = ssl->d1->sent_messages;
piterator iter = pqueue_iterator(sent);
pitem *item;
for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) {
hm_fragment *frag = (hm_fragment *)item->data;
if (dtls1_retransmit_message(ssl, frag) <= 0) {
return -1;
}
}
return 1;
}
/* dtls1_buffer_change_cipher_spec adds a ChangeCipherSpec to the current
* handshake flight, ordered just before the handshake message numbered
* |seq|. */
static int dtls1_buffer_change_cipher_spec(SSL *ssl, uint16_t seq) {
hm_fragment *frag = dtls1_hm_fragment_new(0 /* frag_len */,
0 /* no reassembly */);
if (frag == NULL) {
return 0;
}
frag->msg_header.is_ccs = 1;
frag->msg_header.epoch = ssl->d1->w_epoch;
uint16_t priority = dtls1_get_queue_priority(seq, 1 /* is_ccs */);
uint8_t seq64be[8];
memset(seq64be, 0, sizeof(seq64be));
seq64be[6] = (uint8_t)(priority >> 8);
seq64be[7] = (uint8_t)priority;
pitem *item = pitem_new(seq64be, frag);
if (item == NULL) {
dtls1_hm_fragment_free(frag);
return 0;
}
pqueue_insert(ssl->d1->sent_messages, item);
return 1;
}
int dtls1_buffer_message(SSL *ssl) {
/* this function is called immediately after a message has
* been serialized */
assert(ssl->init_off == 0);
hm_fragment *frag = dtls1_hm_fragment_new(ssl->init_num, 0);
if (!frag) {
return 0;
}
memcpy(frag->fragment, ssl->init_buf->data, ssl->init_num);
assert(ssl->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH ==
(unsigned int)ssl->init_num);
frag->msg_header.msg_len = ssl->d1->w_msg_hdr.msg_len;
frag->msg_header.seq = ssl->d1->w_msg_hdr.seq;
frag->msg_header.type = ssl->d1->w_msg_hdr.type;
frag->msg_header.frag_off = 0;
frag->msg_header.frag_len = ssl->d1->w_msg_hdr.msg_len;
frag->msg_header.is_ccs = 0;
frag->msg_header.epoch = ssl->d1->w_epoch;
uint16_t priority = dtls1_get_queue_priority(frag->msg_header.seq,
0 /* handshake */);
uint8_t seq64be[8];
memset(seq64be, 0, sizeof(seq64be));
seq64be[6] = (uint8_t)(priority >> 8);
seq64be[7] = (uint8_t)priority;
pitem *item = pitem_new(seq64be, frag);
if (item == NULL) {
dtls1_hm_fragment_free(frag);
return 0;
}
pqueue_insert(ssl->d1->sent_messages, item);
return 1;
}
int dtls1_send_change_cipher_spec(SSL *ssl, int a, int b) {
if (ssl->state == a) {
/* Buffer the message to handle retransmits. */
ssl->d1->handshake_write_seq = ssl->d1->next_handshake_write_seq;
dtls1_buffer_change_cipher_spec(ssl, ssl->d1->handshake_write_seq);
ssl->state = b;
}
return dtls1_write_change_cipher_spec(ssl, dtls1_use_current_epoch);
}
/* call this function when the buffered messages are no longer needed */
void dtls1_clear_record_buffer(SSL *ssl) {
pitem *item;
for (item = pqueue_pop(ssl->d1->sent_messages); item != NULL;
item = pqueue_pop(ssl->d1->sent_messages)) {
dtls1_hm_fragment_free((hm_fragment *)item->data);
pitem_free(item);
}
}
/* don't actually do the writing, wait till the MTU has been retrieved */
void dtls1_set_message_header(SSL *ssl, uint8_t mt, unsigned long len,
unsigned short seq_num, unsigned long frag_off,
unsigned long frag_len) {
struct hm_header_st *msg_hdr = &ssl->d1->w_msg_hdr;
msg_hdr->type = mt;
msg_hdr->msg_len = len;
msg_hdr->seq = seq_num;
msg_hdr->frag_off = frag_off;
msg_hdr->frag_len = frag_len;
}
unsigned int dtls1_min_mtu(void) {
return kMinMTU;
}
void dtls1_get_message_header(uint8_t *data,
struct hm_header_st *msg_hdr) {
memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
msg_hdr->type = *(data++);
n2l3(data, msg_hdr->msg_len);
n2s(data, msg_hdr->seq);
n2l3(data, msg_hdr->frag_off);
n2l3(data, msg_hdr->frag_len);
}
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