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/* ssl/d1_both.c */
/*
* DTLS implementation written by Nagendra Modadugu
* (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
*/
/* ====================================================================
* Copyright (c) 1998-2018 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 <limits.h>
#include <string.h>
#include <stdio.h>
#include "ssl_locl.h"
#include <openssl/buffer.h>
#include <openssl/rand.h>
#include <openssl/objects.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
#define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
#define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
if ((end) - (start) <= 8) { \
long ii; \
for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
} else { \
long ii; \
bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \
for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \
bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \
} }
#define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
long ii; \
OPENSSL_assert((msg_len) > 0); \
is_complete = 1; \
if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \
if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \
if (bitmask[ii] != 0xff) { is_complete = 0; break; } }
#if 0
# define RSMBLY_BITMASK_PRINT(bitmask, msg_len) { \
long ii; \
printf("bitmask: "); for (ii = 0; ii < (msg_len); ii++) \
printf("%d ", (bitmask[ii >> 3] & (1 << (ii & 7))) >> (ii & 7)); \
printf("\n"); }
#endif
static unsigned char bitmask_start_values[] =
{ 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80 };
static unsigned char bitmask_end_values[] =
{ 0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f };
/* XDTLS: figure out the right values */
static const unsigned int g_probable_mtu[] = { 1500, 512, 256 };
static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
unsigned long frag_len);
static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p);
static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
unsigned long len,
unsigned short seq_num,
unsigned long frag_off,
unsigned long frag_len);
static long dtls1_get_message_fragment(SSL *s, int st1, int stn, long max,
int *ok);
static hm_fragment *dtls1_hm_fragment_new(unsigned long frag_len,
int reassembly)
{
hm_fragment *frag = NULL;
unsigned char *buf = NULL;
unsigned char *bitmask = NULL;
frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
if (frag == NULL)
return NULL;
if (frag_len) {
buf = (unsigned char *)OPENSSL_malloc(frag_len);
if (buf == NULL) {
OPENSSL_free(frag);
return NULL;
}
}
/* zero length fragment gets zero frag->fragment */
frag->fragment = buf;
/* Initialize reassembly bitmask if necessary */
if (reassembly) {
bitmask =
(unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
if (bitmask == NULL) {
if (buf != NULL)
OPENSSL_free(buf);
OPENSSL_free(frag);
return NULL;
}
memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
}
frag->reassembly = bitmask;
return frag;
}
void dtls1_hm_fragment_free(hm_fragment *frag)
{
if (frag->msg_header.is_ccs) {
EVP_CIPHER_CTX_free(frag->msg_header.
saved_retransmit_state.enc_write_ctx);
EVP_MD_CTX_destroy(frag->msg_header.
saved_retransmit_state.write_hash);
}
if (frag->fragment)
OPENSSL_free(frag->fragment);
if (frag->reassembly)
OPENSSL_free(frag->reassembly);
OPENSSL_free(frag);
}
static int dtls1_query_mtu(SSL *s)
{
if (s->d1->link_mtu) {
s->d1->mtu =
s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
s->d1->link_mtu = 0;
}
/* AHA! Figure out the MTU, and stick to the right size */
if (s->d1->mtu < dtls1_min_mtu(s)) {
if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
s->d1->mtu =
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
/*
* I've seen the kernel return bogus numbers when it doesn't know
* (initial write), so just make sure we have a reasonable number
*/
if (s->d1->mtu < dtls1_min_mtu(s)) {
/* Set to min mtu */
s->d1->mtu = dtls1_min_mtu(s);
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
s->d1->mtu, NULL);
}
} else
return 0;
}
return 1;
}
/*
* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or
* SSL3_RT_CHANGE_CIPHER_SPEC)
*/
int dtls1_do_write(SSL *s, int type)
{
int ret;
unsigned int curr_mtu;
int retry = 1;
unsigned int len, frag_off, mac_size, blocksize, used_len;
if (!dtls1_query_mtu(s))
return -1;
OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu(s)); /* should have something
* reasonable now */
if (s->init_off == 0 && type == SSL3_RT_HANDSHAKE)
OPENSSL_assert(s->init_num ==
(int)s->d1->w_msg_hdr.msg_len +
DTLS1_HM_HEADER_LENGTH);
if (s->write_hash) {
if (s->enc_write_ctx
&& EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_GCM_MODE)
mac_size = 0;
else
mac_size = EVP_MD_CTX_size(s->write_hash);
} else
mac_size = 0;
if (s->enc_write_ctx &&
(EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE))
blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
else
blocksize = 0;
frag_off = 0;
s->rwstate = SSL_NOTHING;
/* s->init_num shouldn't ever be < 0...but just in case */
while (s->init_num > 0) {
if (type == SSL3_RT_HANDSHAKE && s->init_off != 0) {
/* We must be writing a fragment other than the first one */
if (frag_off > 0) {
/* This is the first attempt at writing out this fragment */
if (s->init_off <= DTLS1_HM_HEADER_LENGTH) {
/*
* Each fragment that was already sent must at least have
* contained the message header plus one other byte.
* Therefore |init_off| must have progressed by at least
* |DTLS1_HM_HEADER_LENGTH + 1| bytes. If not something went
* wrong.
*/
return -1;
}
/*
* Adjust |init_off| and |init_num| to allow room for a new
* message header for this fragment.
*/
s->init_off -= DTLS1_HM_HEADER_LENGTH;
s->init_num += DTLS1_HM_HEADER_LENGTH;
} else {
/*
* We must have been called again after a retry so use the
* fragment offset from our last attempt. We do not need
* to adjust |init_off| and |init_num| as above, because
* that should already have been done before the retry.
*/
frag_off = s->d1->w_msg_hdr.frag_off;
}
}
used_len = BIO_wpending(SSL_get_wbio(s)) + DTLS1_RT_HEADER_LENGTH
+ mac_size + blocksize;
if (s->d1->mtu > used_len)
curr_mtu = s->d1->mtu - used_len;
else
curr_mtu = 0;
if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) {
/*
* grr.. we could get an error if MTU picked was wrong
*/
ret = BIO_flush(SSL_get_wbio(s));
if (ret <= 0) {
s->rwstate = SSL_WRITING;
return ret;
}
used_len = DTLS1_RT_HEADER_LENGTH + mac_size + blocksize;
if (s->d1->mtu > used_len + DTLS1_HM_HEADER_LENGTH) {
curr_mtu = s->d1->mtu - used_len;
} else {
/* Shouldn't happen */
return -1;
}
}
/*
* We just checked that s->init_num > 0 so this cast should be safe
*/
if (((unsigned int)s->init_num) > curr_mtu)
len = curr_mtu;
else
len = s->init_num;
/* Shouldn't ever happen */
if (len > INT_MAX)
len = INT_MAX;
/*
* XDTLS: this function is too long. split out the CCS part
*/
if (type == SSL3_RT_HANDSHAKE) {
if (len < DTLS1_HM_HEADER_LENGTH) {
/*
* len is so small that we really can't do anything sensible
* so fail
*/
return -1;
}
dtls1_fix_message_header(s, frag_off,
len - DTLS1_HM_HEADER_LENGTH);
dtls1_write_message_header(s,
(unsigned char *)&s->init_buf->
data[s->init_off]);
}
ret = dtls1_write_bytes(s, type, &s->init_buf->data[s->init_off],
len);
if (ret < 0) {
/*
* might need to update MTU here, but we don't know which
* previous packet caused the failure -- so can't really
* retransmit anything. continue as if everything is fine and
* wait for an alert to handle the retransmit
*/
if (retry && BIO_ctrl(SSL_get_wbio(s),
BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0) {
if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
if (!dtls1_query_mtu(s))
return -1;
/* Have one more go */
retry = 0;
} else
return -1;
} else {
return (-1);
}
} else {
/*
* bad if this assert fails, only part of the handshake message
* got sent. but why would this happen?
*/
OPENSSL_assert(len == (unsigned int)ret);
if (type == SSL3_RT_HANDSHAKE && !s->d1->retransmitting) {
/*
* should not be done for 'Hello Request's, but in that case
* we'll ignore the result anyway
*/
unsigned char *p =
(unsigned char *)&s->init_buf->data[s->init_off];
const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
int xlen;
if (frag_off == 0 && s->version != DTLS1_BAD_VER) {
/*
* reconstruct message header is if it is being sent in
* single fragment
*/
*p++ = msg_hdr->type;
l2n3(msg_hdr->msg_len, p);
s2n(msg_hdr->seq, p);
l2n3(0, p);
l2n3(msg_hdr->msg_len, p);
p -= DTLS1_HM_HEADER_LENGTH;
xlen = ret;
} else {
p += DTLS1_HM_HEADER_LENGTH;
xlen = ret - DTLS1_HM_HEADER_LENGTH;
}
ssl3_finish_mac(s, p, xlen);
}
if (ret == s->init_num) {
if (s->msg_callback)
s->msg_callback(1, s->version, type, s->init_buf->data,
(size_t)(s->init_off + s->init_num), s,
s->msg_callback_arg);
s->init_off = 0; /* done writing this message */
s->init_num = 0;
return (1);
}
s->init_off += ret;
s->init_num -= ret;
ret -= DTLS1_HM_HEADER_LENGTH;
frag_off += ret;
/*
* We save the fragment offset for the next fragment so we have it
* available in case of an IO retry. We don't know the length of the
* next fragment yet so just set that to 0 for now. It will be
* updated again later.
*/
dtls1_fix_message_header(s, frag_off, 0);
}
}
return (0);
}
/*
* Obtain handshake message of message type 'mt' (any if mt == -1), maximum
* acceptable body length 'max'. Read an entire handshake message. Handshake
* messages arrive in fragments.
*/
long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
{
int i, al;
struct hm_header_st *msg_hdr;
unsigned char *p;
unsigned long msg_len;
/*
* s3->tmp is used to store messages that are unexpected, caused by the
* absence of an optional handshake message
*/
if (s->s3->tmp.reuse_message) {
s->s3->tmp.reuse_message = 0;
if ((mt >= 0) && (s->s3->tmp.message_type != mt)) {
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS1_GET_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
*ok = 1;
s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
s->init_num = (int)s->s3->tmp.message_size;
return s->init_num;
}
msg_hdr = &s->d1->r_msg_hdr;
memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
again:
i = dtls1_get_message_fragment(s, st1, stn, max, ok);
if (i == DTLS1_HM_BAD_FRAGMENT || i == DTLS1_HM_FRAGMENT_RETRY) {
/* bad fragment received */
goto again;
} else if (i <= 0 && !*ok) {
return i;
}
/*
* Don't change the *message* read sequence number while listening. For
* the *record* write sequence we reflect the ClientHello sequence number
* when listening.
*/
if (s->d1->listen)
memcpy(s->s3->write_sequence, s->s3->read_sequence,
sizeof(s->s3->write_sequence));
else
s->d1->handshake_read_seq++;
if (mt >= 0 && s->s3->tmp.message_type != mt) {
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS1_GET_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
p = (unsigned char *)s->init_buf->data;
msg_len = msg_hdr->msg_len;
/* reconstruct message header */
*(p++) = msg_hdr->type;
l2n3(msg_len, p);
s2n(msg_hdr->seq, p);
l2n3(0, p);
l2n3(msg_len, p);
if (s->version != DTLS1_BAD_VER) {
p -= DTLS1_HM_HEADER_LENGTH;
msg_len += DTLS1_HM_HEADER_LENGTH;
}
ssl3_finish_mac(s, p, msg_len);
if (s->msg_callback)
s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
p, msg_len, s, s->msg_callback_arg);
memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
return s->init_num;
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
*ok = 0;
return -1;
}
static int dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr,
int max)
{
size_t frag_off, frag_len, msg_len;
msg_len = msg_hdr->msg_len;
frag_off = msg_hdr->frag_off;
frag_len = msg_hdr->frag_len;
/* sanity checking */
if ((frag_off + frag_len) > msg_len) {
SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
return SSL_AD_ILLEGAL_PARAMETER;
}
if ((frag_off + frag_len) > (unsigned long)max) {
SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
return SSL_AD_ILLEGAL_PARAMETER;
}
if (s->d1->r_msg_hdr.frag_off == 0) { /* first fragment */
/*
* msg_len is limited to 2^24, but is effectively checked against max
* above
*
* Make buffer slightly larger than message length as a precaution
* against small OOB reads e.g. CVE-2016-6306
*/
if (!BUF_MEM_grow_clean
(s->init_buf, msg_len + DTLS1_HM_HEADER_LENGTH + 16)) {
SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, ERR_R_BUF_LIB);
return SSL_AD_INTERNAL_ERROR;
}
s->s3->tmp.message_size = msg_len;
s->d1->r_msg_hdr.msg_len = msg_len;
s->s3->tmp.message_type = msg_hdr->type;
s->d1->r_msg_hdr.type = msg_hdr->type;
s->d1->r_msg_hdr.seq = msg_hdr->seq;
} else if (msg_len != s->d1->r_msg_hdr.msg_len) {
/*
* They must be playing with us! BTW, failure to enforce upper limit
* would open possibility for buffer overrun.
*/
SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT, SSL_R_EXCESSIVE_MESSAGE_SIZE);
return SSL_AD_ILLEGAL_PARAMETER;
}
return 0; /* no error */
}
static int dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
{
/*-
* (0) check whether the desired fragment is available
* if so:
* (1) copy over the fragment to s->init_buf->data[]
* (2) update s->init_num
*/
pitem *item;
hm_fragment *frag;
int al;
*ok = 0;
do {
item = pqueue_peek(s->d1->buffered_messages);
if (item == NULL)
return 0;
frag = (hm_fragment *)item->data;
if (frag->msg_header.seq < s->d1->handshake_read_seq) {
/* This is a stale message that has been buffered so clear it */
pqueue_pop(s->d1->buffered_messages);
dtls1_hm_fragment_free(frag);
pitem_free(item);
item = NULL;
frag = NULL;
}
} while (item == NULL);
/* Don't return if reassembly still in progress */
if (frag->reassembly != NULL)
return 0;
if (s->d1->handshake_read_seq == frag->msg_header.seq) {
unsigned long frag_len = frag->msg_header.frag_len;
pqueue_pop(s->d1->buffered_messages);
al = dtls1_preprocess_fragment(s, &frag->msg_header, max);
/* al will be 0 if no alert */
if (al == 0 && frag->msg_header.frag_len > 0) {
unsigned char *p =
(unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
memcpy(&p[frag->msg_header.frag_off], frag->fragment,
frag->msg_header.frag_len);
}
dtls1_hm_fragment_free(frag);
pitem_free(item);
if (al == 0) {
*ok = 1;
return frag_len;
}
ssl3_send_alert(s, SSL3_AL_FATAL, al);
s->init_num = 0;
*ok = 0;
return -1;
} else
return 0;
}
/*
* dtls1_max_handshake_message_len returns the maximum number of bytes
* permitted in a DTLS handshake message for |s|. The minimum is 16KB, but
* may be greater if the maximum certificate list size requires it.
*/
static unsigned long dtls1_max_handshake_message_len(const SSL *s)
{
unsigned long max_len =
DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
if (max_len < (unsigned long)s->max_cert_list)
return s->max_cert_list;
return max_len;
}
static int
dtls1_reassemble_fragment(SSL *s, const struct hm_header_st *msg_hdr, int *ok)
{
hm_fragment *frag = NULL;
pitem *item = NULL;
int i = -1, is_complete;
unsigned char seq64be[8];
unsigned long frag_len = msg_hdr->frag_len;
if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len ||
msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
goto err;
if (frag_len == 0)
return DTLS1_HM_FRAGMENT_RETRY;
/* Try to find item in queue */
memset(seq64be, 0, sizeof(seq64be));
seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
seq64be[7] = (unsigned char)msg_hdr->seq;
item = pqueue_find(s->d1->buffered_messages, seq64be);
if (item == NULL) {
frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
if (frag == NULL)
goto err;
memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
frag->msg_header.frag_len = frag->msg_header.msg_len;
frag->msg_header.frag_off = 0;
} else {
frag = (hm_fragment *)item->data;
if (frag->msg_header.msg_len != msg_hdr->msg_len) {
item = NULL;
frag = NULL;
goto err;
}
}
/*
* If message is already reassembled, this must be a retransmit and can
* be dropped. In this case item != NULL and so frag does not need to be
* freed.
*/
if (frag->reassembly == NULL) {
unsigned char devnull[256];
while (frag_len) {
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
devnull,
frag_len >
sizeof(devnull) ? sizeof(devnull) :
frag_len, 0);
if (i <= 0)
goto err;
frag_len -= i;
}
return DTLS1_HM_FRAGMENT_RETRY;
}
/* read the body of the fragment (header has already been read */
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
frag->fragment + msg_hdr->frag_off,
frag_len, 0);
if ((unsigned long)i != frag_len)
i = -1;
if (i <= 0)
goto err;
RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
(long)(msg_hdr->frag_off + frag_len));
RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
is_complete);
if (is_complete) {
OPENSSL_free(frag->reassembly);
frag->reassembly = NULL;
}
if (item == NULL) {
item = pitem_new(seq64be, frag);
if (item == NULL) {
i = -1;
goto err;
}
item = pqueue_insert(s->d1->buffered_messages, item);
/*
* pqueue_insert fails iff a duplicate item is inserted. However,
* |item| cannot be a duplicate. If it were, |pqueue_find|, above,
* would have returned it and control would never have reached this
* branch.
*/
OPENSSL_assert(item != NULL);
}
return DTLS1_HM_FRAGMENT_RETRY;
err:
if (frag != NULL && item == NULL)
dtls1_hm_fragment_free(frag);
*ok = 0;
return i;
}
static int
dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st *msg_hdr,
int *ok)
{
int i = -1;
hm_fragment *frag = NULL;
pitem *item = NULL;
unsigned char seq64be[8];
unsigned long frag_len = msg_hdr->frag_len;
if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len)
goto err;
/* Try to find item in queue, to prevent duplicate entries */
memset(seq64be, 0, sizeof(seq64be));
seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
seq64be[7] = (unsigned char)msg_hdr->seq;
item = pqueue_find(s->d1->buffered_messages, seq64be);
/*
* If we already have an entry and this one is a fragment, don't discard
* it and rather try to reassemble it.
*/
if (item != NULL && frag_len != msg_hdr->msg_len)
item = NULL;
/*
* Discard the message if sequence number was already there, is too far
* in the future, already in the queue or if we received a FINISHED
* before the SERVER_HELLO, which then must be a stale retransmit.
*/
if (msg_hdr->seq <= s->d1->handshake_read_seq ||
msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
(s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
{
unsigned char devnull[256];
while (frag_len) {
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
devnull,
frag_len >
sizeof(devnull) ? sizeof(devnull) :
frag_len, 0);
if (i <= 0)
goto err;
frag_len -= i;
}
} else {
if (frag_len != msg_hdr->msg_len)
return dtls1_reassemble_fragment(s, msg_hdr, ok);
if (frag_len > dtls1_max_handshake_message_len(s))
goto err;
frag = dtls1_hm_fragment_new(frag_len, 0);
if (frag == NULL)
goto err;
memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
if (frag_len) {
/*
* read the body of the fragment (header has already been read
*/
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
frag->fragment, frag_len, 0);
if ((unsigned long)i != frag_len)
i = -1;
if (i <= 0)
goto err;
}
item = pitem_new(seq64be, frag);
if (item == NULL)
goto err;
item = pqueue_insert(s->d1->buffered_messages, item);
/*
* pqueue_insert fails iff a duplicate item is inserted. However,
* |item| cannot be a duplicate. If it were, |pqueue_find|, above,
* would have returned it. Then, either |frag_len| !=
* |msg_hdr->msg_len| in which case |item| is set to NULL and it will
* have been processed with |dtls1_reassemble_fragment|, above, or
* the record will have been discarded.
*/
OPENSSL_assert(item != NULL);
}
return DTLS1_HM_FRAGMENT_RETRY;
err:
if (frag != NULL && item == NULL)
dtls1_hm_fragment_free(frag);
*ok = 0;
return i;
}
static long
dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
{
unsigned char wire[DTLS1_HM_HEADER_LENGTH];
unsigned long len, frag_off, frag_len;
int i, al;
struct hm_header_st msg_hdr;
redo:
/* see if we have the required fragment already */
if ((frag_len = dtls1_retrieve_buffered_fragment(s, max, ok)) || *ok) {
if (*ok)
s->init_num = frag_len;
return frag_len;
}
/* read handshake message header */
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, wire,
DTLS1_HM_HEADER_LENGTH, 0);
if (i <= 0) { /* nbio, or an error */
s->rwstate = SSL_READING;
*ok = 0;
return i;
}
/* Handshake fails if message header is incomplete */
if (i != DTLS1_HM_HEADER_LENGTH) {
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT, SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
/* parse the message fragment header */
dtls1_get_message_header(wire, &msg_hdr);
len = msg_hdr.msg_len;
frag_off = msg_hdr.frag_off;
frag_len = msg_hdr.frag_len;
/*
* We must have at least frag_len bytes left in the record to be read.
* Fragments must not span records.
*/
if (frag_len > s->s3->rrec.length) {
al = SSL3_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT, SSL_R_BAD_LENGTH);
goto f_err;
}
/*
* if this is a future (or stale) message it gets buffered
* (or dropped)--no further processing at this time
* While listening, we accept seq 1 (ClientHello with cookie)
* although we're still expecting seq 0 (ClientHello)
*/
if (msg_hdr.seq != s->d1->handshake_read_seq
&& !(s->d1->listen && msg_hdr.seq == 1))
return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
if (frag_len && frag_len < len)
return dtls1_reassemble_fragment(s, &msg_hdr, ok);
if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
wire[0] == SSL3_MT_HELLO_REQUEST) {
/*
* The server may always send 'Hello Request' messages -- we are
* doing a handshake anyway now, so ignore them if their format is
* correct. Does not count for 'Finished' MAC.
*/
if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) {
if (s->msg_callback)
s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
wire, DTLS1_HM_HEADER_LENGTH, s,
s->msg_callback_arg);
s->init_num = 0;
goto redo;
} else { /* Incorrectly formated Hello request */
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,
SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
}
if ((al = dtls1_preprocess_fragment(s, &msg_hdr, max)))
goto f_err;
if (frag_len > 0) {
unsigned char *p =
(unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
&p[frag_off], frag_len, 0);
/*
* This shouldn't ever fail due to NBIO because we already checked
* that we have enough data in the record
*/
if (i <= 0) {
s->rwstate = SSL_READING;
*ok = 0;
return i;
}
} else
i = 0;
/*
* XDTLS: an incorrectly formatted fragment should cause the handshake
* to fail
*/
if (i != (int)frag_len) {
al = SSL3_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT, SSL3_AD_ILLEGAL_PARAMETER);
goto f_err;
}
*ok = 1;
s->state = stn;
/*
* Note that s->init_num is *not* used as current offset in
* s->init_buf->data, but as a counter summing up fragments' lengths: as
* soon as they sum up to handshake packet length, we assume we have got
* all the fragments.
*/
s->init_num = frag_len;
return frag_len;
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
s->init_num = 0;
*ok = 0;
return (-1);
}
/*-
* for these 2 messages, we need to
* ssl->enc_read_ctx re-init
* ssl->s3->read_sequence zero
* ssl->s3->read_mac_secret re-init
* ssl->session->read_sym_enc assign
* ssl->session->read_compression assign
* ssl->session->read_hash assign
*/
int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
{
unsigned char *p;
if (s->state == a) {
p = (unsigned char *)s->init_buf->data;
*p++ = SSL3_MT_CCS;
s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
s->init_num = DTLS1_CCS_HEADER_LENGTH;
if (s->version == DTLS1_BAD_VER) {
s->d1->next_handshake_write_seq++;
s2n(s->d1->handshake_write_seq, p);
s->init_num += 2;
}
s->init_off = 0;
dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
s->d1->handshake_write_seq, 0, 0);
/* buffer the message to handle re-xmits */
dtls1_buffer_message(s, 1);
s->state = b;
}
/* SSL3_ST_CW_CHANGE_B */
return (dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC));
}
int dtls1_read_failed(SSL *s, int code)
{
if (code > 0) {
#ifdef TLS_DEBUG
fprintf(stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
#endif
return 1;
}
if (!dtls1_is_timer_expired(s)) {
/*
* not a timeout, none of our business, let higher layers handle
* this. in fact it's probably an error
*/
return code;
}
#ifndef OPENSSL_NO_HEARTBEATS
/* done, no need to send a retransmit */
if (!SSL_in_init(s) && !s->tlsext_hb_pending)
#else
/* done, no need to send a retransmit */
if (!SSL_in_init(s))
#endif
{
BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
return code;
}
#if 0 /* for now, each alert contains only one
* record number */
item = pqueue_peek(state->rcvd_records);
if (item) {
/* send an alert immediately for all the missing records */
} else
#endif
#if 0 /* no more alert sending, just retransmit the
* last set of messages */
if (state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
ssl3_send_alert(s, SSL3_AL_WARNING,
DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
#endif
return dtls1_handle_timeout(s);
}
int dtls1_get_queue_priority(unsigned short seq, int is_ccs)
{
/*
* 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;
}
int dtls1_retransmit_buffered_messages(SSL *s)
{
pqueue sent = s->d1->sent_messages;
piterator iter;
pitem *item;
hm_fragment *frag;
int found = 0;
iter = pqueue_iterator(sent);
for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) {
frag = (hm_fragment *)item->data;
if (dtls1_retransmit_message(s, (unsigned short)
dtls1_get_queue_priority
(frag->msg_header.seq,
frag->msg_header.is_ccs), 0,
&found) <= 0 && found) {
#ifdef TLS_DEBUG
fprintf(stderr, "dtls1_retransmit_message() failed\n");
#endif
return -1;
}
}
return 1;
}
int dtls1_buffer_message(SSL *s, int is_ccs)
{
pitem *item;
hm_fragment *frag;
unsigned char seq64be[8];
/*
* this function is called immediately after a message has been
* serialized
*/
OPENSSL_assert(s->init_off == 0);
frag = dtls1_hm_fragment_new(s->init_num, 0);
if (!frag)
return 0;
memcpy(frag->fragment, s->init_buf->data, s->init_num);
if (is_ccs) {
/* For DTLS1_BAD_VER the header length is non-standard */
OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
((s->version==DTLS1_BAD_VER)?3:DTLS1_CCS_HEADER_LENGTH)
== (unsigned int)s->init_num);
} else {
OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
}
frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
frag->msg_header.seq = s->d1->w_msg_hdr.seq;
frag->msg_header.type = s->d1->w_msg_hdr.type;
frag->msg_header.frag_off = 0;
frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
frag->msg_header.is_ccs = is_ccs;
/* save current state */
frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
frag->msg_header.saved_retransmit_state.compress = s->compress;
frag->msg_header.saved_retransmit_state.session = s->session;
frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
memset(seq64be, 0, sizeof(seq64be));
seq64be[6] =
(unsigned
char)(dtls1_get_queue_priority(frag->msg_header.seq,
frag->msg_header.is_ccs) >> 8);
seq64be[7] =
(unsigned
char)(dtls1_get_queue_priority(frag->msg_header.seq,
frag->msg_header.is_ccs));
item = pitem_new(seq64be, frag);
if (item == NULL) {
dtls1_hm_fragment_free(frag);
return 0;
}
#if 0
fprintf(stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
fprintf(stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
fprintf(stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
#endif
pqueue_insert(s->d1->sent_messages, item);
return 1;
}
int
dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
int *found)
{
int ret;
/* XDTLS: for now assuming that read/writes are blocking */
pitem *item;
hm_fragment *frag;
unsigned long header_length;
unsigned char seq64be[8];
struct dtls1_retransmit_state saved_state;
unsigned char save_write_sequence[8] = {0, 0, 0, 0, 0, 0, 0, 0};
/*-
OPENSSL_assert(s->init_num == 0);
OPENSSL_assert(s->init_off == 0);
*/
/* XDTLS: the requested message ought to be found, otherwise error */
memset(seq64be, 0, sizeof(seq64be));
seq64be[6] = (unsigned char)(seq >> 8);
seq64be[7] = (unsigned char)seq;
item = pqueue_find(s->d1->sent_messages, seq64be);
if (item == NULL) {
#ifdef TLS_DEBUG
fprintf(stderr, "retransmit: message %d non-existant\n", seq);
#endif
*found = 0;
return 0;
}
*found = 1;
frag = (hm_fragment *)item->data;
if (frag->msg_header.is_ccs)
header_length = DTLS1_CCS_HEADER_LENGTH;
else
header_length = DTLS1_HM_HEADER_LENGTH;
memcpy(s->init_buf->data, frag->fragment,
frag->msg_header.msg_len + header_length);
s->init_num = frag->msg_header.msg_len + header_length;
dtls1_set_message_header_int(s, frag->msg_header.type,
frag->msg_header.msg_len,
frag->msg_header.seq, 0,
frag->msg_header.frag_len);
/* save current state */
saved_state.enc_write_ctx = s->enc_write_ctx;
saved_state.write_hash = s->write_hash;
saved_state.compress = s->compress;
saved_state.session = s->session;
saved_state.epoch = s->d1->w_epoch;
saved_state.epoch = s->d1->w_epoch;
s->d1->retransmitting = 1;
/* restore state in which the message was originally sent */
s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
s->compress = frag->msg_header.saved_retransmit_state.compress;
s->session = frag->msg_header.saved_retransmit_state.session;
s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
if (frag->msg_header.saved_retransmit_state.epoch ==
saved_state.epoch - 1) {
memcpy(save_write_sequence, s->s3->write_sequence,
sizeof(s->s3->write_sequence));
memcpy(s->s3->write_sequence, s->d1->last_write_sequence,
sizeof(s->s3->write_sequence));
}
ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
/* restore current state */
s->enc_write_ctx = saved_state.enc_write_ctx;
s->write_hash = saved_state.write_hash;
s->compress = saved_state.compress;
s->session = saved_state.session;
s->d1->w_epoch = saved_state.epoch;
if (frag->msg_header.saved_retransmit_state.epoch ==
saved_state.epoch - 1) {
memcpy(s->d1->last_write_sequence, s->s3->write_sequence,
sizeof(s->s3->write_sequence));
memcpy(s->s3->write_sequence, save_write_sequence,
sizeof(s->s3->write_sequence));
}
s->d1->retransmitting = 0;
(void)BIO_flush(SSL_get_wbio(s));
return ret;
}
unsigned char *dtls1_set_message_header(SSL *s, unsigned char *p,
unsigned char mt, unsigned long len,
unsigned long frag_off,
unsigned long frag_len)
{
/* Don't change sequence numbers while listening */
if (frag_off == 0 && !s->d1->listen) {
s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
s->d1->next_handshake_write_seq++;
}
dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
frag_off, frag_len);
return p += DTLS1_HM_HEADER_LENGTH;
}
/* don't actually do the writing, wait till the MTU has been retrieved */
static void
dtls1_set_message_header_int(SSL *s, unsigned char mt,
unsigned long len, unsigned short seq_num,
unsigned long frag_off, unsigned long frag_len)
{
struct hm_header_st *msg_hdr = &s->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;
}
static void
dtls1_fix_message_header(SSL *s, unsigned long frag_off,
unsigned long frag_len)
{
struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
msg_hdr->frag_off = frag_off;
msg_hdr->frag_len = frag_len;
}
static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p)
{
struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
*p++ = msg_hdr->type;
l2n3(msg_hdr->msg_len, p);
s2n(msg_hdr->seq, p);
l2n3(msg_hdr->frag_off, p);
l2n3(msg_hdr->frag_len, p);
return p;
}
unsigned int dtls1_link_min_mtu(void)
{
return (g_probable_mtu[(sizeof(g_probable_mtu) /
sizeof(g_probable_mtu[0])) - 1]);
}
unsigned int dtls1_min_mtu(SSL *s)
{
return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
}
void
dtls1_get_message_header(unsigned char *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);
}
void dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
{
memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
ccs_hdr->type = *(data++);
}
int dtls1_shutdown(SSL *s)
{
int ret;
#ifndef OPENSSL_NO_SCTP
BIO *wbio;
wbio = SSL_get_wbio(s);
if (wbio != NULL && BIO_dgram_is_sctp(wbio) &&
!(s->shutdown & SSL_SENT_SHUTDOWN)) {
ret = BIO_dgram_sctp_wait_for_dry(wbio);
if (ret < 0)
return -1;
if (ret == 0)
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
NULL);
}
#endif
ret = ssl3_shutdown(s);
#ifndef OPENSSL_NO_SCTP
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
#endif
return ret;
}
#ifndef OPENSSL_NO_HEARTBEATS
int dtls1_process_heartbeat(SSL *s)
{
unsigned char *p = &s->s3->rrec.data[0], *pl;
unsigned short hbtype;
unsigned int payload;
unsigned int padding = 16; /* Use minimum padding */
if (s->msg_callback)
s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
&s->s3->rrec.data[0], s->s3->rrec.length,
s, s->msg_callback_arg);
/* Read type and payload length first */
if (1 + 2 + 16 > s->s3->rrec.length)
return 0; /* silently discard */
if (s->s3->rrec.length > SSL3_RT_MAX_PLAIN_LENGTH)
return 0; /* silently discard per RFC 6520 sec. 4 */
hbtype = *p++;
n2s(p, payload);
if (1 + 2 + payload + 16 > s->s3->rrec.length)
return 0; /* silently discard per RFC 6520 sec. 4 */
pl = p;
if (hbtype == TLS1_HB_REQUEST) {
unsigned char *buffer, *bp;
unsigned int write_length = 1 /* heartbeat type */ +
2 /* heartbeat length */ +
payload + padding;
int r;
if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
return 0;
/*
* Allocate memory for the response, size is 1 byte message type,
* plus 2 bytes payload length, plus payload, plus padding
*/
buffer = OPENSSL_malloc(write_length);
if (buffer == NULL)
return -1;
bp = buffer;
/* Enter response type, length and copy payload */
*bp++ = TLS1_HB_RESPONSE;
s2n(payload, bp);
memcpy(bp, pl, payload);
bp += payload;
/* Random padding */
if (RAND_bytes(bp, padding) <= 0) {
OPENSSL_free(buffer);
return -1;
}
r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
if (r >= 0 && s->msg_callback)
s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
buffer, write_length, s, s->msg_callback_arg);
OPENSSL_free(buffer);
if (r < 0)
return r;
} else if (hbtype == TLS1_HB_RESPONSE) {
unsigned int seq;
/*
* We only send sequence numbers (2 bytes unsigned int), and 16
* random bytes, so we just try to read the sequence number
*/
n2s(pl, seq);
if (payload == 18 && seq == s->tlsext_hb_seq) {
dtls1_stop_timer(s);
s->tlsext_hb_seq++;
s->tlsext_hb_pending = 0;
}
}
return 0;
}
int dtls1_heartbeat(SSL *s)
{
unsigned char *buf, *p;
int ret = -1;
unsigned int payload = 18; /* Sequence number + random bytes */
unsigned int padding = 16; /* Use minimum padding */
/* Only send if peer supports and accepts HB requests... */
if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS) {
SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
return -1;
}
/* ...and there is none in flight yet... */
if (s->tlsext_hb_pending) {
SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING);
return -1;
}
/* ...and no handshake in progress. */
if (SSL_in_init(s) || s->in_handshake) {
SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE);
return -1;
}
/*
* Check if padding is too long, payload and padding must not exceed 2^14
* - 3 = 16381 bytes in total.
*/
OPENSSL_assert(payload + padding <= 16381);
/*-
* Create HeartBeat message, we just use a sequence number
* as payload to distuingish different messages and add
* some random stuff.
* - Message Type, 1 byte
* - Payload Length, 2 bytes (unsigned int)
* - Payload, the sequence number (2 bytes uint)
* - Payload, random bytes (16 bytes uint)
* - Padding
*/
buf = OPENSSL_malloc(1 + 2 + payload + padding);
if (buf == NULL)
goto err;
p = buf;
/* Message Type */
*p++ = TLS1_HB_REQUEST;
/* Payload length (18 bytes here) */
s2n(payload, p);
/* Sequence number */
s2n(s->tlsext_hb_seq, p);
/* 16 random bytes */
if (RAND_bytes(p, 16) <= 0)
goto err;
p += 16;
/* Random padding */
if (RAND_bytes(p, padding) <= 0)
goto err;
ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
if (ret >= 0) {
if (s->msg_callback)
s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
buf, 3 + payload + padding,
s, s->msg_callback_arg);
dtls1_start_timer(s);
s->tlsext_hb_pending = 1;
}
err:
OPENSSL_free(buf);
return ret;
}
#endif
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