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openssl/ssl/statem/statem_dtls.c
Sergio Garcia Murillo 50b4a9ba13 GH356: Change assert to normal error 
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
2016-05-05 17:27:30 -04:00

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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 <limits.h>
#include <string.h>
#include <stdio.h>
#include "../ssl_locl.h"
#include "statem_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; } }
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 };
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 int dtls_get_reassembled_message(SSL *s, long *len);
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 = OPENSSL_malloc(sizeof(*frag));
if (frag == NULL)
return NULL;
if (frag_len) {
buf = 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 = OPENSSL_zalloc(RSMBLY_BITMASK_SIZE(frag_len));
if (bitmask == NULL) {
OPENSSL_free(buf);
OPENSSL_free(frag);
return NULL;
}
}
frag->reassembly = bitmask;
return frag;
}
void dtls1_hm_fragment_free(hm_fragment *frag)
{
if (!frag)
return;
if (frag->msg_header.is_ccs) {
EVP_CIPHER_CTX_free(frag->msg_header.
saved_retransmit_state.enc_write_ctx);
EVP_MD_CTX_free(frag->msg_header.saved_retransmit_state.write_hash);
}
OPENSSL_free(frag->fragment);
OPENSSL_free(frag->reassembly);
OPENSSL_free(frag);
}
/*
* 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;
if (s->d1->mtu < dtls1_min_mtu(s))
/* should have something reasonable now */
return -1;
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_flags(EVP_CIPHER_CTX_cipher(s->enc_write_ctx)) &
EVP_CIPH_FLAG_AEAD_CIPHER) != 0)
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_CTX_block_size(s->enc_write_ctx);
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);
}
int dtls_get_message(SSL *s, int *mt, unsigned long *len)
{
struct hm_header_st *msg_hdr;
unsigned char *p;
unsigned long msg_len;
int ok;
long tmplen;
msg_hdr = &s->d1->r_msg_hdr;
memset(msg_hdr, 0, sizeof(*msg_hdr));
again:
ok = dtls_get_reassembled_message(s, &tmplen);
if (tmplen == DTLS1_HM_BAD_FRAGMENT
|| tmplen == DTLS1_HM_FRAGMENT_RETRY) {
/* bad fragment received */
goto again;
} else if (tmplen <= 0 && !ok) {
return 0;
}
*mt = s->s3->tmp.message_type;
p = (unsigned char *)s->init_buf->data;
if (*mt == SSL3_MT_CHANGE_CIPHER_SPEC) {
if (s->msg_callback) {
s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC,
p, 1, s, s->msg_callback_arg);
}
/*
* This isn't a real handshake message so skip the processing below.
*/
*len = (unsigned long)tmplen;
return 1;
}
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, 0, sizeof(*msg_hdr));
s->d1->handshake_read_seq++;
s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
*len = s->init_num;
return 1;
}
static int dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr)
{
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 (s->d1->r_msg_hdr.frag_off == 0) { /* first fragment */
/*
* msg_len is limited to 2^24, but is effectively checked against max
* above
*/
if (!BUF_MEM_grow_clean
(s->init_buf, msg_len + DTLS1_HM_HEADER_LENGTH)) {
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, 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;
item = pqueue_peek(s->d1->buffered_messages);
if (item == NULL)
return 0;
frag = (hm_fragment *)item->data;
/* 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);
if (al == 0) { /* no alert */
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, NULL,
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, NULL,
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 (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, NULL,
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, NULL,
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 (item == NULL)
dtls1_hm_fragment_free(frag);
*ok = 0;
return i;
}
static int dtls_get_reassembled_message(SSL *s, long *len)
{
unsigned char wire[DTLS1_HM_HEADER_LENGTH];
unsigned long mlen, frag_off, frag_len;
int i, al, recvd_type;
struct hm_header_st msg_hdr;
int ok;
redo:
/* see if we have the required fragment already */
if ((frag_len = dtls1_retrieve_buffered_fragment(s, &ok)) || ok) {
if (ok)
s->init_num = frag_len;
*len = frag_len;
return ok;
}
/* read handshake message header */
i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, &recvd_type, wire,
DTLS1_HM_HEADER_LENGTH, 0);
if (i <= 0) { /* nbio, or an error */
s->rwstate = SSL_READING;
*len = i;
return 0;
}
if(recvd_type == SSL3_RT_CHANGE_CIPHER_SPEC) {
if (wire[0] != SSL3_MT_CCS) {
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS_GET_REASSEMBLED_MESSAGE,
SSL_R_BAD_CHANGE_CIPHER_SPEC);
goto f_err;
}
memcpy(s->init_buf->data, wire, i);
s->init_num = i - 1;
s->init_msg = s->init_buf->data + 1;
s->s3->tmp.message_type = SSL3_MT_CHANGE_CIPHER_SPEC;
s->s3->tmp.message_size = i - 1;
*len = i - 1;
return 1;
}
/* Handshake fails if message header is incomplete */
if (i != DTLS1_HM_HEADER_LENGTH) {
al = SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS_GET_REASSEMBLED_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
/* parse the message fragment header */
dtls1_get_message_header(wire, &msg_hdr);
mlen = 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 > RECORD_LAYER_get_rrec_length(&s->rlayer)) {
al = SSL3_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_DTLS_GET_REASSEMBLED_MESSAGE, 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) {
*len = dtls1_process_out_of_seq_message(s, &msg_hdr, &ok);
return ok;
}
if (frag_len && frag_len < mlen) {
*len = dtls1_reassemble_fragment(s, &msg_hdr, &ok);
return 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_DTLS_GET_REASSEMBLED_MESSAGE,
SSL_R_UNEXPECTED_MESSAGE);
goto f_err;
}
}
if ((al = dtls1_preprocess_fragment(s, &msg_hdr)))
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, NULL,
&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;
*len = i;
return 0;
}
} 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_DTLS_GET_REASSEMBLED_MESSAGE, SSL3_AD_ILLEGAL_PARAMETER);
goto f_err;
}
/*
* 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.
*/
*len = s->init_num = frag_len;
return 1;
f_err:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
s->init_num = 0;
*len = -1;
return 0;
}
/*-
* for these 2 messages, we need to
* ssl->enc_read_ctx re-init
* ssl->rlayer.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 dtls_construct_change_cipher_spec(SSL *s)
{
unsigned char *p;
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 */
if (!dtls1_buffer_message(s, 1)) {
SSLerr(SSL_F_DTLS_CONSTRUCT_CHANGE_CIPHER_SPEC, ERR_R_INTERNAL_ERROR);
return 0;
}
return 1;
}
#ifndef OPENSSL_NO_SCTP
WORK_STATE dtls_wait_for_dry(SSL *s)
{
int ret;
/* read app data until dry event */
ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
if (ret < 0)
return WORK_ERROR;
if (ret == 0) {
s->s3->in_read_app_data = 2;
s->rwstate = SSL_READING;
BIO_clear_retry_flags(SSL_get_rbio(s));
BIO_set_retry_read(SSL_get_rbio(s));
return WORK_MORE_A;
}
return WORK_FINISHED_CONTINUE;
}
#endif
int dtls1_read_failed(SSL *s, int code)
{
if (code > 0) {
fprintf(stderr, "dtls1_read_failed(); invalid state reached\n");
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;
}
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),
&found) <= 0 && found) {
fprintf(stderr, "dtls1_retransmit_message() failed\n");
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 == NULL)
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 =
DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer);
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;
}
pqueue_insert(s->d1->sent_messages, item);
return 1;
}
int
dtls1_retransmit_message(SSL *s, unsigned short seq, 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;
/*-
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) {
fprintf(stderr, "retransmit: message %d non-existant\n", seq);
*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 = DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer);
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;
DTLS_RECORD_LAYER_set_saved_w_epoch(&s->rlayer,
frag->msg_header.saved_retransmit_state.epoch);
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;
DTLS_RECORD_LAYER_set_saved_w_epoch(&s->rlayer, saved_state.epoch);
s->d1->retransmitting = 0;
(void)BIO_flush(SSL_get_wbio(s));
return ret;
}
/* call this function when the buffered messages are no longer needed */
void dtls1_clear_record_buffer(SSL *s)
{
pitem *item;
for (item = pqueue_pop(s->d1->sent_messages);
item != NULL; item = pqueue_pop(s->d1->sent_messages)) {
dtls1_hm_fragment_free((hm_fragment *)item->data);
pitem_free(item);
}
}
void dtls1_set_message_header(SSL *s,
unsigned char mt, unsigned long len,
unsigned long frag_off,
unsigned long frag_len)
{
if (frag_off == 0) {
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);
}
/* 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;
}
void
dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
{
memset(msg_hdr, 0, sizeof(*msg_hdr));
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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