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openssl/ssl/d1_pkt.c
Dr. Stephen Henson 40088d8b81 DTLS version usage fixes. 
Make DTLS behave like TLS when negotiating version: record layer has
DTLS 1.0, message version is 1.2.

Tolerate different version numbers if version hasn't been negotiated
yet.
2013-09-17 18:55:41 +01:00

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/* ssl/d1_pkt.c */
/*
* 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 <stdio.h>
#include <errno.h>
#define USE_SOCKETS
#include "ssl_locl.h"
#include <openssl/evp.h>
#include <openssl/buffer.h>
#include <openssl/pqueue.h>
#include <openssl/rand.h>
/* mod 128 saturating subtract of two 64-bit values in big-endian order */
static int satsub64be(const unsigned char *v1,const unsigned char *v2)
{ int ret,sat,brw,i;
if (sizeof(long) == 8) do
{ const union { long one; char little; } is_endian = {1};
long l;
if (is_endian.little) break;
/* not reached on little-endians */
/* following test is redundant, because input is
* always aligned, but I take no chances... */
if (((size_t)v1|(size_t)v2)&0x7) break;
l = *((long *)v1);
l -= *((long *)v2);
if (l>128) return 128;
else if (l<-128) return -128;
else return (int)l;
} while (0);
ret = (int)v1[7]-(int)v2[7];
sat = 0;
brw = ret>>8; /* brw is either 0 or -1 */
if (ret & 0x80)
{ for (i=6;i>=0;i--)
{ brw += (int)v1[i]-(int)v2[i];
sat |= ~brw;
brw >>= 8;
}
}
else
{ for (i=6;i>=0;i--)
{ brw += (int)v1[i]-(int)v2[i];
sat |= brw;
brw >>= 8;
}
}
brw <<= 8; /* brw is either 0 or -256 */
if (sat&0xff) return brw | 0x80;
else return brw + (ret&0xFF);
}
static int have_handshake_fragment(SSL *s, int type, unsigned char *buf,
int len, int peek);
static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap);
static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap);
static DTLS1_BITMAP *dtls1_get_bitmap(SSL *s, SSL3_RECORD *rr,
unsigned int *is_next_epoch);
#if 0
static int dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr,
unsigned short *priority, unsigned long *offset);
#endif
static int dtls1_buffer_record(SSL *s, record_pqueue *q,
unsigned char *priority);
static int dtls1_process_record(SSL *s);
/* copy buffered record into SSL structure */
static int
dtls1_copy_record(SSL *s, pitem *item)
{
DTLS1_RECORD_DATA *rdata;
rdata = (DTLS1_RECORD_DATA *)item->data;
if (s->s3->rbuf.buf != NULL)
OPENSSL_free(s->s3->rbuf.buf);
s->packet = rdata->packet;
s->packet_length = rdata->packet_length;
memcpy(&(s->s3->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER));
memcpy(&(s->s3->rrec), &(rdata->rrec), sizeof(SSL3_RECORD));
/* Set proper sequence number for mac calculation */
memcpy(&(s->s3->read_sequence[2]), &(rdata->packet[5]), 6);
return(1);
}
static int
dtls1_buffer_record(SSL *s, record_pqueue *queue, unsigned char *priority)
{
DTLS1_RECORD_DATA *rdata;
pitem *item;
/* Limit the size of the queue to prevent DOS attacks */
if (pqueue_size(queue->q) >= 100)
return 0;
rdata = OPENSSL_malloc(sizeof(DTLS1_RECORD_DATA));
item = pitem_new(priority, rdata);
if (rdata == NULL || item == NULL)
{
if (rdata != NULL) OPENSSL_free(rdata);
if (item != NULL) pitem_free(item);
SSLerr(SSL_F_DTLS1_BUFFER_RECORD, ERR_R_INTERNAL_ERROR);
return(0);
}
rdata->packet = s->packet;
rdata->packet_length = s->packet_length;
memcpy(&(rdata->rbuf), &(s->s3->rbuf), sizeof(SSL3_BUFFER));
memcpy(&(rdata->rrec), &(s->s3->rrec), sizeof(SSL3_RECORD));
item->data = rdata;
#ifndef OPENSSL_NO_SCTP
/* Store bio_dgram_sctp_rcvinfo struct */
if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
(s->state == SSL3_ST_SR_FINISHED_A || s->state == SSL3_ST_CR_FINISHED_A)) {
BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SCTP_GET_RCVINFO, sizeof(rdata->recordinfo), &rdata->recordinfo);
}
#endif
/* insert should not fail, since duplicates are dropped */
if (pqueue_insert(queue->q, item) == NULL)
{
OPENSSL_free(rdata);
pitem_free(item);
return(0);
}
s->packet = NULL;
s->packet_length = 0;
memset(&(s->s3->rbuf), 0, sizeof(SSL3_BUFFER));
memset(&(s->s3->rrec), 0, sizeof(SSL3_RECORD));
if (!ssl3_setup_buffers(s))
{
SSLerr(SSL_F_DTLS1_BUFFER_RECORD, ERR_R_INTERNAL_ERROR);
OPENSSL_free(rdata);
pitem_free(item);
return(0);
}
return(1);
}
static int
dtls1_retrieve_buffered_record(SSL *s, record_pqueue *queue)
{
pitem *item;
item = pqueue_pop(queue->q);
if (item)
{
dtls1_copy_record(s, item);
OPENSSL_free(item->data);
pitem_free(item);
return(1);
}
return(0);
}
/* retrieve a buffered record that belongs to the new epoch, i.e., not processed
* yet */
#define dtls1_get_unprocessed_record(s) \
dtls1_retrieve_buffered_record((s), \
&((s)->d1->unprocessed_rcds))
/* retrieve a buffered record that belongs to the current epoch, ie, processed */
#define dtls1_get_processed_record(s) \
dtls1_retrieve_buffered_record((s), \
&((s)->d1->processed_rcds))
static int
dtls1_process_buffered_records(SSL *s)
{
pitem *item;
item = pqueue_peek(s->d1->unprocessed_rcds.q);
if (item)
{
/* Check if epoch is current. */
if (s->d1->unprocessed_rcds.epoch != s->d1->r_epoch)
return(1); /* Nothing to do. */
/* Process all the records. */
while (pqueue_peek(s->d1->unprocessed_rcds.q))
{
dtls1_get_unprocessed_record(s);
if ( ! dtls1_process_record(s))
return(0);
dtls1_buffer_record(s, &(s->d1->processed_rcds),
s->s3->rrec.seq_num);
}
}
/* sync epoch numbers once all the unprocessed records
* have been processed */
s->d1->processed_rcds.epoch = s->d1->r_epoch;
s->d1->unprocessed_rcds.epoch = s->d1->r_epoch + 1;
return(1);
}
#if 0
static int
dtls1_get_buffered_record(SSL *s)
{
pitem *item;
PQ_64BIT priority =
(((PQ_64BIT)s->d1->handshake_read_seq) << 32) |
((PQ_64BIT)s->d1->r_msg_hdr.frag_off);
if ( ! SSL_in_init(s)) /* if we're not (re)negotiating,
nothing buffered */
return 0;
item = pqueue_peek(s->d1->rcvd_records);
if (item && item->priority == priority)
{
/* Check if we've received the record of interest. It must be
* a handshake record, since data records as passed up without
* buffering */
DTLS1_RECORD_DATA *rdata;
item = pqueue_pop(s->d1->rcvd_records);
rdata = (DTLS1_RECORD_DATA *)item->data;
if (s->s3->rbuf.buf != NULL)
OPENSSL_free(s->s3->rbuf.buf);
s->packet = rdata->packet;
s->packet_length = rdata->packet_length;
memcpy(&(s->s3->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER));
memcpy(&(s->s3->rrec), &(rdata->rrec), sizeof(SSL3_RECORD));
OPENSSL_free(item->data);
pitem_free(item);
/* s->d1->next_expected_seq_num++; */
return(1);
}
return 0;
}
#endif
static int
dtls1_process_record(SSL *s)
{
int i,al;
int enc_err;
SSL_SESSION *sess;
SSL3_RECORD *rr;
unsigned int mac_size;
unsigned char md[EVP_MAX_MD_SIZE];
rr= &(s->s3->rrec);
sess = s->session;
/* At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
* and we have that many bytes in s->packet
*/
rr->input= &(s->packet[DTLS1_RT_HEADER_LENGTH]);
/* ok, we can now read from 's->packet' data into 'rr'
* rr->input points at rr->length bytes, which
* need to be copied into rr->data by either
* the decryption or by the decompression
* When the data is 'copied' into the rr->data buffer,
* rr->input will be pointed at the new buffer */
/* We now have - encrypted [ MAC [ compressed [ plain ] ] ]
* rr->length bytes of encrypted compressed stuff. */
/* check is not needed I believe */
if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
{
al=SSL_AD_RECORD_OVERFLOW;
SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
goto f_err;
}
/* decrypt in place in 'rr->input' */
rr->data=rr->input;
rr->orig_len=rr->length;
enc_err = s->method->ssl3_enc->enc(s,0);
/* enc_err is:
* 0: (in non-constant time) if the record is publically invalid.
* 1: if the padding is valid
* -1: if the padding is invalid */
if (enc_err == 0)
{
/* For DTLS we simply ignore bad packets. */
rr->length = 0;
s->packet_length = 0;
goto err;
}
#ifdef TLS_DEBUG
printf("dec %d\n",rr->length);
{ unsigned int z; for (z=0; z<rr->length; z++) printf("%02X%c",rr->data[z],((z+1)%16)?' ':'\n'); }
printf("\n");
#endif
/* r->length is now the compressed data plus mac */
if ((sess != NULL) &&
(s->enc_read_ctx != NULL) &&
(EVP_MD_CTX_md(s->read_hash) != NULL))
{
/* s->read_hash != NULL => mac_size != -1 */
unsigned char *mac = NULL;
unsigned char mac_tmp[EVP_MAX_MD_SIZE];
mac_size=EVP_MD_CTX_size(s->read_hash);
OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
/* orig_len is the length of the record before any padding was
* removed. This is public information, as is the MAC in use,
* therefore we can safely process the record in a different
* amount of time if it's too short to possibly contain a MAC.
*/
if (rr->orig_len < mac_size ||
/* CBC records must have a padding length byte too. */
(EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
rr->orig_len < mac_size+1))
{
al=SSL_AD_DECODE_ERROR;
SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
goto f_err;
}
if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE)
{
/* We update the length so that the TLS header bytes
* can be constructed correctly but we need to extract
* the MAC in constant time from within the record,
* without leaking the contents of the padding bytes.
* */
mac = mac_tmp;
ssl3_cbc_copy_mac(mac_tmp, rr, mac_size);
rr->length -= mac_size;
}
else
{
/* In this case there's no padding, so |rec->orig_len|
* equals |rec->length| and we checked that there's
* enough bytes for |mac_size| above. */
rr->length -= mac_size;
mac = &rr->data[rr->length];
}
i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
enc_err = -1;
if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
enc_err = -1;
}
if (enc_err < 0)
{
/* decryption failed, silently discard message */
rr->length = 0;
s->packet_length = 0;
goto err;
}
/* r->length is now just compressed */
if (s->expand != NULL)
{
if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH)
{
al=SSL_AD_RECORD_OVERFLOW;
SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_COMPRESSED_LENGTH_TOO_LONG);
goto f_err;
}
if (!ssl3_do_uncompress(s))
{
al=SSL_AD_DECOMPRESSION_FAILURE;
SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_BAD_DECOMPRESSION);
goto f_err;
}
}
if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH)
{
al=SSL_AD_RECORD_OVERFLOW;
SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_DATA_LENGTH_TOO_LONG);
goto f_err;
}
rr->off=0;
/* So at this point the following is true
* ssl->s3->rrec.type is the type of record
* ssl->s3->rrec.length == number of bytes in record
* ssl->s3->rrec.off == offset to first valid byte
* ssl->s3->rrec.data == where to take bytes from, increment
* after use :-).
*/
/* we have pulled in a full packet so zero things */
s->packet_length=0;
dtls1_record_bitmap_update(s, &(s->d1->bitmap));/* Mark receipt of record. */
return(1);
f_err:
ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
return(0);
}
/* Call this to get a new input record.
* It will return <= 0 if more data is needed, normally due to an error
* or non-blocking IO.
* When it finishes, one packet has been decoded and can be found in
* ssl->s3->rrec.type - is the type of record
* ssl->s3->rrec.data, - data
* ssl->s3->rrec.length, - number of bytes
*/
/* used only by dtls1_read_bytes */
int dtls1_get_record(SSL *s)
{
int ssl_major,ssl_minor;
int i,n;
SSL3_RECORD *rr;
unsigned char *p = NULL;
unsigned short version;
DTLS1_BITMAP *bitmap;
unsigned int is_next_epoch;
rr= &(s->s3->rrec);
/* The epoch may have changed. If so, process all the
* pending records. This is a non-blocking operation. */
dtls1_process_buffered_records(s);
/* if we're renegotiating, then there may be buffered records */
if (dtls1_get_processed_record(s))
return 1;
/* get something from the wire */
again:
/* check if we have the header */
if ( (s->rstate != SSL_ST_READ_BODY) ||
(s->packet_length < DTLS1_RT_HEADER_LENGTH))
{
n=ssl3_read_n(s, DTLS1_RT_HEADER_LENGTH, s->s3->rbuf.len, 0);
/* read timeout is handled by dtls1_read_bytes */
if (n <= 0) return(n); /* error or non-blocking */
/* this packet contained a partial record, dump it */
if (s->packet_length != DTLS1_RT_HEADER_LENGTH)
{
s->packet_length = 0;
goto again;
}
s->rstate=SSL_ST_READ_BODY;
p=s->packet;
if (s->msg_callback)
s->msg_callback(0, 0, SSL3_RT_HEADER, p, DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
/* Pull apart the header into the DTLS1_RECORD */
rr->type= *(p++);
ssl_major= *(p++);
ssl_minor= *(p++);
version=(ssl_major<<8)|ssl_minor;
/* sequence number is 64 bits, with top 2 bytes = epoch */
n2s(p,rr->epoch);
memcpy(&(s->s3->read_sequence[2]), p, 6);
p+=6;
n2s(p,rr->length);
/* Lets check version */
if (!s->first_packet)
{
if (version != s->version)
{
/* unexpected version, silently discard */
rr->length = 0;
s->packet_length = 0;
goto again;
}
}
if ((version & 0xff00) != (s->version & 0xff00))
{
/* wrong version, silently discard record */
rr->length = 0;
s->packet_length = 0;
goto again;
}
if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
{
/* record too long, silently discard it */
rr->length = 0;
s->packet_length = 0;
goto again;
}
/* now s->rstate == SSL_ST_READ_BODY */
}
/* s->rstate == SSL_ST_READ_BODY, get and decode the data */
if (rr->length > s->packet_length-DTLS1_RT_HEADER_LENGTH)
{
/* now s->packet_length == DTLS1_RT_HEADER_LENGTH */
i=rr->length;
n=ssl3_read_n(s,i,i,1);
if (n <= 0) return(n); /* error or non-blocking io */
/* this packet contained a partial record, dump it */
if ( n != i)
{
rr->length = 0;
s->packet_length = 0;
goto again;
}
/* now n == rr->length,
* and s->packet_length == DTLS1_RT_HEADER_LENGTH + rr->length */
}
s->rstate=SSL_ST_READ_HEADER; /* set state for later operations */
/* match epochs. NULL means the packet is dropped on the floor */
bitmap = dtls1_get_bitmap(s, rr, &is_next_epoch);
if ( bitmap == NULL)
{
rr->length = 0;
s->packet_length = 0; /* dump this record */
goto again; /* get another record */
}
#ifndef OPENSSL_NO_SCTP
/* Only do replay check if no SCTP bio */
if (!BIO_dgram_is_sctp(SSL_get_rbio(s)))
{
#endif
/* Check whether this is a repeat, or aged record.
* Don't check if we're listening and this message is
* a ClientHello. They can look as if they're replayed,
* since they arrive from different connections and
* would be dropped unnecessarily.
*/
if (!(s->d1->listen && rr->type == SSL3_RT_HANDSHAKE &&
*p == SSL3_MT_CLIENT_HELLO) &&
!dtls1_record_replay_check(s, bitmap))
{
rr->length = 0;
s->packet_length=0; /* dump this record */
goto again; /* get another record */
}
#ifndef OPENSSL_NO_SCTP
}
#endif
/* just read a 0 length packet */
if (rr->length == 0) goto again;
/* If this record is from the next epoch (either HM or ALERT),
* and a handshake is currently in progress, buffer it since it
* cannot be processed at this time. However, do not buffer
* anything while listening.
*/
if (is_next_epoch)
{
if ((SSL_in_init(s) || s->in_handshake) && !s->d1->listen)
{
dtls1_buffer_record(s, &(s->d1->unprocessed_rcds), rr->seq_num);
}
rr->length = 0;
s->packet_length = 0;
goto again;
}
if (!dtls1_process_record(s))
{
rr->length = 0;
s->packet_length = 0; /* dump this record */
goto again; /* get another record */
}
return(1);
}
/* Return up to 'len' payload bytes received in 'type' records.
* 'type' is one of the following:
*
* - SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
* - SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
* - 0 (during a shutdown, no data has to be returned)
*
* If we don't have stored data to work from, read a SSL/TLS record first
* (possibly multiple records if we still don't have anything to return).
*
* This function must handle any surprises the peer may have for us, such as
* Alert records (e.g. close_notify), ChangeCipherSpec records (not really
* a surprise, but handled as if it were), or renegotiation requests.
* Also if record payloads contain fragments too small to process, we store
* them until there is enough for the respective protocol (the record protocol
* may use arbitrary fragmentation and even interleaving):
* Change cipher spec protocol
* just 1 byte needed, no need for keeping anything stored
* Alert protocol
* 2 bytes needed (AlertLevel, AlertDescription)
* Handshake protocol
* 4 bytes needed (HandshakeType, uint24 length) -- we just have
* to detect unexpected Client Hello and Hello Request messages
* here, anything else is handled by higher layers
* Application data protocol
* none of our business
*/
int dtls1_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
{
int al,i,j,ret;
unsigned int n;
SSL3_RECORD *rr;
void (*cb)(const SSL *ssl,int type2,int val)=NULL;
if (s->s3->rbuf.buf == NULL) /* Not initialized yet */
if (!ssl3_setup_buffers(s))
return(-1);
/* XXX: check what the second '&& type' is about */
if ((type && (type != SSL3_RT_APPLICATION_DATA) &&
(type != SSL3_RT_HANDSHAKE) && type) ||
(peek && (type != SSL3_RT_APPLICATION_DATA)))
{
SSLerr(SSL_F_DTLS1_READ_BYTES, ERR_R_INTERNAL_ERROR);
return -1;
}
/* check whether there's a handshake message (client hello?) waiting */
if ( (ret = have_handshake_fragment(s, type, buf, len, peek)))
return ret;
/* Now s->d1->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */
#ifndef OPENSSL_NO_SCTP
/* Continue handshake if it had to be interrupted to read
* app data with SCTP.
*/
if ((!s->in_handshake && SSL_in_init(s)) ||
(BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
(s->state == DTLS1_SCTP_ST_SR_READ_SOCK || s->state == DTLS1_SCTP_ST_CR_READ_SOCK) &&
s->s3->in_read_app_data != 2))
#else
if (!s->in_handshake && SSL_in_init(s))
#endif
{
/* type == SSL3_RT_APPLICATION_DATA */
i=s->handshake_func(s);
if (i < 0) return(i);
if (i == 0)
{
SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
return(-1);
}
}
start:
s->rwstate=SSL_NOTHING;
/* s->s3->rrec.type - is the type of record
* s->s3->rrec.data, - data
* s->s3->rrec.off, - offset into 'data' for next read
* s->s3->rrec.length, - number of bytes. */
rr = &(s->s3->rrec);
/* We are not handshaking and have no data yet,
* so process data buffered during the last handshake
* in advance, if any.
*/
if (s->state == SSL_ST_OK && rr->length == 0)
{
pitem *item;
item = pqueue_pop(s->d1->buffered_app_data.q);
if (item)
{
#ifndef OPENSSL_NO_SCTP
/* Restore bio_dgram_sctp_rcvinfo struct */
if (BIO_dgram_is_sctp(SSL_get_rbio(s)))
{
DTLS1_RECORD_DATA *rdata = (DTLS1_RECORD_DATA *) item->data;
BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SCTP_SET_RCVINFO, sizeof(rdata->recordinfo), &rdata->recordinfo);
}
#endif
dtls1_copy_record(s, item);
OPENSSL_free(item->data);
pitem_free(item);
}
}
/* Check for timeout */
if (dtls1_handle_timeout(s) > 0)
goto start;
/* get new packet if necessary */
if ((rr->length == 0) || (s->rstate == SSL_ST_READ_BODY))
{
ret=dtls1_get_record(s);
if (ret <= 0)
{
ret = dtls1_read_failed(s, ret);
/* anything other than a timeout is an error */
if (ret <= 0)
return(ret);
else
goto start;
}
}
if (s->d1->listen && rr->type != SSL3_RT_HANDSHAKE)
{
rr->length = 0;
goto start;
}
/* we now have a packet which can be read and processed */
if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
* reset by ssl3_get_finished */
&& (rr->type != SSL3_RT_HANDSHAKE))
{
/* We now have application data between CCS and Finished.
* Most likely the packets were reordered on their way, so
* buffer the application data for later processing rather
* than dropping the connection.
*/
dtls1_buffer_record(s, &(s->d1->buffered_app_data), rr->seq_num);
rr->length = 0;
goto start;
}
/* If the other end has shut down, throw anything we read away
* (even in 'peek' mode) */
if (s->shutdown & SSL_RECEIVED_SHUTDOWN)
{
rr->length=0;
s->rwstate=SSL_NOTHING;
return(0);
}
if (type == rr->type) /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
{
/* make sure that we are not getting application data when we
* are doing a handshake for the first time */
if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
(s->enc_read_ctx == NULL))
{
al=SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_APP_DATA_IN_HANDSHAKE);
goto f_err;
}
if (len <= 0) return(len);
if ((unsigned int)len > rr->length)
n = rr->length;
else
n = (unsigned int)len;
memcpy(buf,&(rr->data[rr->off]),n);
if (!peek)
{
rr->length-=n;
rr->off+=n;
if (rr->length == 0)
{
s->rstate=SSL_ST_READ_HEADER;
rr->off=0;
}
}
#ifndef OPENSSL_NO_SCTP
/* We were about to renegotiate but had to read
* belated application data first, so retry.
*/
if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
rr->type == SSL3_RT_APPLICATION_DATA &&
(s->state == DTLS1_SCTP_ST_SR_READ_SOCK || s->state == DTLS1_SCTP_ST_CR_READ_SOCK))
{
s->rwstate=SSL_READING;
BIO_clear_retry_flags(SSL_get_rbio(s));
BIO_set_retry_read(SSL_get_rbio(s));
}
/* We might had to delay a close_notify alert because
* of reordered app data. If there was an alert and there
* is no message to read anymore, finally set shutdown.
*/
if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
s->d1->shutdown_received && !BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s)))
{
s->shutdown |= SSL_RECEIVED_SHUTDOWN;
return(0);
}
#endif
return(n);
}
/* If we get here, then type != rr->type; if we have a handshake
* message, then it was unexpected (Hello Request or Client Hello). */
/* In case of record types for which we have 'fragment' storage,
* fill that so that we can process the data at a fixed place.
*/
{
unsigned int k, dest_maxlen = 0;
unsigned char *dest = NULL;
unsigned int *dest_len = NULL;
if (rr->type == SSL3_RT_HANDSHAKE)
{
dest_maxlen = sizeof s->d1->handshake_fragment;
dest = s->d1->handshake_fragment;
dest_len = &s->d1->handshake_fragment_len;
}
else if (rr->type == SSL3_RT_ALERT)
{
dest_maxlen = sizeof(s->d1->alert_fragment);
dest = s->d1->alert_fragment;
dest_len = &s->d1->alert_fragment_len;
}
#ifndef OPENSSL_NO_HEARTBEATS
else if (rr->type == TLS1_RT_HEARTBEAT)
{
dtls1_process_heartbeat(s);
/* Exit and notify application to read again */
rr->length = 0;
s->rwstate=SSL_READING;
BIO_clear_retry_flags(SSL_get_rbio(s));
BIO_set_retry_read(SSL_get_rbio(s));
return(-1);
}
#endif
/* else it's a CCS message, or application data or wrong */
else if (rr->type != SSL3_RT_CHANGE_CIPHER_SPEC)
{
/* Application data while renegotiating
* is allowed. Try again reading.
*/
if (rr->type == SSL3_RT_APPLICATION_DATA)
{
BIO *bio;
s->s3->in_read_app_data=2;
bio=SSL_get_rbio(s);
s->rwstate=SSL_READING;
BIO_clear_retry_flags(bio);
BIO_set_retry_read(bio);
return(-1);
}
/* Not certain if this is the right error handling */
al=SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
goto f_err;
}
if (dest_maxlen > 0)
{
/* XDTLS: In a pathalogical case, the Client Hello
* may be fragmented--don't always expect dest_maxlen bytes */
if ( rr->length < dest_maxlen)
{
#ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
/*
* for normal alerts rr->length is 2, while
* dest_maxlen is 7 if we were to handle this
* non-existing alert...
*/
FIX ME
#endif
s->rstate=SSL_ST_READ_HEADER;
rr->length = 0;
goto start;
}
/* now move 'n' bytes: */
for ( k = 0; k < dest_maxlen; k++)
{
dest[k] = rr->data[rr->off++];
rr->length--;
}
*dest_len = dest_maxlen;
}
}
/* s->d1->handshake_fragment_len == 12 iff rr->type == SSL3_RT_HANDSHAKE;
* s->d1->alert_fragment_len == 7 iff rr->type == SSL3_RT_ALERT.
* (Possibly rr is 'empty' now, i.e. rr->length may be 0.) */
/* If we are a client, check for an incoming 'Hello Request': */
if ((!s->server) &&
(s->d1->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) &&
(s->d1->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) &&
(s->session != NULL) && (s->session->cipher != NULL))
{
s->d1->handshake_fragment_len = 0;
if ((s->d1->handshake_fragment[1] != 0) ||
(s->d1->handshake_fragment[2] != 0) ||
(s->d1->handshake_fragment[3] != 0))
{
al=SSL_AD_DECODE_ERROR;
SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_BAD_HELLO_REQUEST);
goto err;
}
/* no need to check sequence number on HELLO REQUEST messages */
if (s->msg_callback)
s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
s->d1->handshake_fragment, 4, s, s->msg_callback_arg);
if (SSL_is_init_finished(s) &&
!(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
!s->s3->renegotiate)
{
s->d1->handshake_read_seq++;
s->new_session = 1;
ssl3_renegotiate(s);
if (ssl3_renegotiate_check(s))
{
i=s->handshake_func(s);
if (i < 0) return(i);
if (i == 0)
{
SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
return(-1);
}
if (!(s->mode & SSL_MODE_AUTO_RETRY))
{
if (s->s3->rbuf.left == 0) /* no read-ahead left? */
{
BIO *bio;
/* In the case where we try to read application data,
* but we trigger an SSL handshake, we return -1 with
* the retry option set. Otherwise renegotiation may
* cause nasty problems in the blocking world */
s->rwstate=SSL_READING;
bio=SSL_get_rbio(s);
BIO_clear_retry_flags(bio);
BIO_set_retry_read(bio);
return(-1);
}
}
}
}
/* we either finished a handshake or ignored the request,
* now try again to obtain the (application) data we were asked for */
goto start;
}
if (s->d1->alert_fragment_len >= DTLS1_AL_HEADER_LENGTH)
{
int alert_level = s->d1->alert_fragment[0];
int alert_descr = s->d1->alert_fragment[1];
s->d1->alert_fragment_len = 0;
if (s->msg_callback)
s->msg_callback(0, s->version, SSL3_RT_ALERT,
s->d1->alert_fragment, 2, s, s->msg_callback_arg);
if (s->info_callback != NULL)
cb=s->info_callback;
else if (s->ctx->info_callback != NULL)
cb=s->ctx->info_callback;
if (cb != NULL)
{
j = (alert_level << 8) | alert_descr;
cb(s, SSL_CB_READ_ALERT, j);
}
if (alert_level == 1) /* warning */
{
s->s3->warn_alert = alert_descr;
if (alert_descr == SSL_AD_CLOSE_NOTIFY)
{
#ifndef OPENSSL_NO_SCTP
/* With SCTP and streams the socket may deliver app data
* after a close_notify alert. We have to check this
* first so that nothing gets discarded.
*/
if (BIO_dgram_is_sctp(SSL_get_rbio(s)) &&
BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s)))
{
s->d1->shutdown_received = 1;
s->rwstate=SSL_READING;
BIO_clear_retry_flags(SSL_get_rbio(s));
BIO_set_retry_read(SSL_get_rbio(s));
return -1;
}
#endif
s->shutdown |= SSL_RECEIVED_SHUTDOWN;
return(0);
}
#if 0
/* XXX: this is a possible improvement in the future */
/* now check if it's a missing record */
if (alert_descr == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE)
{
unsigned short seq;
unsigned int frag_off;
unsigned char *p = &(s->d1->alert_fragment[2]);
n2s(p, seq);
n2l3(p, frag_off);
dtls1_retransmit_message(s,
dtls1_get_queue_priority(frag->msg_header.seq, 0),
frag_off, &found);
if ( ! found && SSL_in_init(s))
{
/* fprintf( stderr,"in init = %d\n", SSL_in_init(s)); */
/* requested a message not yet sent,
send an alert ourselves */
ssl3_send_alert(s,SSL3_AL_WARNING,
DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
}
}
#endif
}
else if (alert_level == 2) /* fatal */
{
char tmp[16];
s->rwstate=SSL_NOTHING;
s->s3->fatal_alert = alert_descr;
SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_AD_REASON_OFFSET + alert_descr);
BIO_snprintf(tmp,sizeof tmp,"%d",alert_descr);
ERR_add_error_data(2,"SSL alert number ",tmp);
s->shutdown|=SSL_RECEIVED_SHUTDOWN;
SSL_CTX_remove_session(s->ctx,s->session);
return(0);
}
else
{
al=SSL_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNKNOWN_ALERT_TYPE);
goto f_err;
}
goto start;
}
if (s->shutdown & SSL_SENT_SHUTDOWN) /* but we have not received a shutdown */
{
s->rwstate=SSL_NOTHING;
rr->length=0;
return(0);
}
if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
{
struct ccs_header_st ccs_hdr;
unsigned int ccs_hdr_len = DTLS1_CCS_HEADER_LENGTH;
dtls1_get_ccs_header(rr->data, &ccs_hdr);
if (s->version == DTLS1_BAD_VER)
ccs_hdr_len = 3;
/* 'Change Cipher Spec' is just a single byte, so we know
* exactly what the record payload has to look like */
/* XDTLS: check that epoch is consistent */
if ( (rr->length != ccs_hdr_len) ||
(rr->off != 0) || (rr->data[0] != SSL3_MT_CCS))
{
i=SSL_AD_ILLEGAL_PARAMETER;
SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_BAD_CHANGE_CIPHER_SPEC);
goto err;
}
rr->length=0;
if (s->msg_callback)
s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC,
rr->data, 1, s, s->msg_callback_arg);
/* We can't process a CCS now, because previous handshake
* messages are still missing, so just drop it.
*/
if (!s->d1->change_cipher_spec_ok)
{
goto start;
}
s->d1->change_cipher_spec_ok = 0;
s->s3->change_cipher_spec=1;
if (!ssl3_do_change_cipher_spec(s))
goto err;
/* do this whenever CCS is processed */
dtls1_reset_seq_numbers(s, SSL3_CC_READ);
if (s->version == DTLS1_BAD_VER)
s->d1->handshake_read_seq++;
#ifndef OPENSSL_NO_SCTP
/* Remember that a CCS has been received,
* so that an old key of SCTP-Auth can be
* deleted when a CCS is sent. Will be ignored
* if no SCTP is used
*/
BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_AUTH_CCS_RCVD, 1, NULL);
#endif
goto start;
}
/* Unexpected handshake message (Client Hello, or protocol violation) */
if ((s->d1->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) &&
!s->in_handshake)
{
struct hm_header_st msg_hdr;
/* this may just be a stale retransmit */
dtls1_get_message_header(rr->data, &msg_hdr);
if( rr->epoch != s->d1->r_epoch)
{
rr->length = 0;
goto start;
}
/* If we are server, we may have a repeated FINISHED of the
* client here, then retransmit our CCS and FINISHED.
*/
if (msg_hdr.type == SSL3_MT_FINISHED)
{
if (dtls1_check_timeout_num(s) < 0)
return -1;
dtls1_retransmit_buffered_messages(s);
rr->length = 0;
goto start;
}
if (((s->state&SSL_ST_MASK) == SSL_ST_OK) &&
!(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS))
{
#if 0 /* worked only because C operator preferences are not as expected (and
* because this is not really needed for clients except for detecting
* protocol violations): */
s->state=SSL_ST_BEFORE|(s->server)
?SSL_ST_ACCEPT
:SSL_ST_CONNECT;
#else
s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
#endif
s->renegotiate=1;
s->new_session=1;
}
i=s->handshake_func(s);
if (i < 0) return(i);
if (i == 0)
{
SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
return(-1);
}
if (!(s->mode & SSL_MODE_AUTO_RETRY))
{
if (s->s3->rbuf.left == 0) /* no read-ahead left? */
{
BIO *bio;
/* In the case where we try to read application data,
* but we trigger an SSL handshake, we return -1 with
* the retry option set. Otherwise renegotiation may
* cause nasty problems in the blocking world */
s->rwstate=SSL_READING;
bio=SSL_get_rbio(s);
BIO_clear_retry_flags(bio);
BIO_set_retry_read(bio);
return(-1);
}
}
goto start;
}
switch (rr->type)
{
default:
#ifndef OPENSSL_NO_TLS
/* TLS just ignores unknown message types */
if (s->version == TLS1_VERSION)
{
rr->length = 0;
goto start;
}
#endif
al=SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
goto f_err;
case SSL3_RT_CHANGE_CIPHER_SPEC:
case SSL3_RT_ALERT:
case SSL3_RT_HANDSHAKE:
/* we already handled all of these, with the possible exception
* of SSL3_RT_HANDSHAKE when s->in_handshake is set, but that
* should not happen when type != rr->type */
al=SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS1_READ_BYTES,ERR_R_INTERNAL_ERROR);
goto f_err;
case SSL3_RT_APPLICATION_DATA:
/* At this point, we were expecting handshake data,
* but have application data. If the library was
* running inside ssl3_read() (i.e. in_read_app_data
* is set) and it makes sense to read application data
* at this point (session renegotiation not yet started),
* we will indulge it.
*/
if (s->s3->in_read_app_data &&
(s->s3->total_renegotiations != 0) &&
((
(s->state & SSL_ST_CONNECT) &&
(s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
(s->state <= SSL3_ST_CR_SRVR_HELLO_A)
) || (
(s->state & SSL_ST_ACCEPT) &&
(s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
(s->state >= SSL3_ST_SR_CLNT_HELLO_A)
)
))
{
s->s3->in_read_app_data=2;
return(-1);
}
else
{
al=SSL_AD_UNEXPECTED_MESSAGE;
SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
goto f_err;
}
}
/* not reached */
f_err:
ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
return(-1);
}
int
dtls1_write_app_data_bytes(SSL *s, int type, const void *buf_, int len)
{
int i;
#ifndef OPENSSL_NO_SCTP
/* Check if we have to continue an interrupted handshake
* for reading belated app data with SCTP.
*/
if ((SSL_in_init(s) && !s->in_handshake) ||
(BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
(s->state == DTLS1_SCTP_ST_SR_READ_SOCK || s->state == DTLS1_SCTP_ST_CR_READ_SOCK)))
#else
if (SSL_in_init(s) && !s->in_handshake)
#endif
{
i=s->handshake_func(s);
if (i < 0) return(i);
if (i == 0)
{
SSLerr(SSL_F_DTLS1_WRITE_APP_DATA_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
return -1;
}
}
if (len > SSL3_RT_MAX_PLAIN_LENGTH)
{
SSLerr(SSL_F_DTLS1_WRITE_APP_DATA_BYTES,SSL_R_DTLS_MESSAGE_TOO_BIG);
return -1;
}
i = dtls1_write_bytes(s, type, buf_, len);
return i;
}
/* this only happens when a client hello is received and a handshake
* is started. */
static int
have_handshake_fragment(SSL *s, int type, unsigned char *buf,
int len, int peek)
{
if ((type == SSL3_RT_HANDSHAKE) && (s->d1->handshake_fragment_len > 0))
/* (partially) satisfy request from storage */
{
unsigned char *src = s->d1->handshake_fragment;
unsigned char *dst = buf;
unsigned int k,n;
/* peek == 0 */
n = 0;
while ((len > 0) && (s->d1->handshake_fragment_len > 0))
{
*dst++ = *src++;
len--; s->d1->handshake_fragment_len--;
n++;
}
/* move any remaining fragment bytes: */
for (k = 0; k < s->d1->handshake_fragment_len; k++)
s->d1->handshake_fragment[k] = *src++;
return n;
}
return 0;
}
/* Call this to write data in records of type 'type'
* It will return <= 0 if not all data has been sent or non-blocking IO.
*/
int dtls1_write_bytes(SSL *s, int type, const void *buf, int len)
{
int i;
OPENSSL_assert(len <= SSL3_RT_MAX_PLAIN_LENGTH);
s->rwstate=SSL_NOTHING;
i=do_dtls1_write(s, type, buf, len, 0);
return i;
}
int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len, int create_empty_fragment)
{
unsigned char *p,*pseq;
int i,mac_size,clear=0;
int prefix_len = 0;
int eivlen;
SSL3_RECORD *wr;
SSL3_BUFFER *wb;
SSL_SESSION *sess;
/* first check if there is a SSL3_BUFFER still being written
* out. This will happen with non blocking IO */
if (s->s3->wbuf.left != 0)
{
OPENSSL_assert(0); /* XDTLS: want to see if we ever get here */
return(ssl3_write_pending(s,type,buf,len));
}
/* If we have an alert to send, lets send it */
if (s->s3->alert_dispatch)
{
i=s->method->ssl_dispatch_alert(s);
if (i <= 0)
return(i);
/* if it went, fall through and send more stuff */
}
if (len == 0 && !create_empty_fragment)
return 0;
wr= &(s->s3->wrec);
wb= &(s->s3->wbuf);
sess=s->session;
if ( (sess == NULL) ||
(s->enc_write_ctx == NULL) ||
(EVP_MD_CTX_md(s->write_hash) == NULL))
clear=1;
if (clear)
mac_size=0;
else
{
mac_size=EVP_MD_CTX_size(s->write_hash);
if (mac_size < 0)
goto err;
}
/* DTLS implements explicit IV, so no need for empty fragments */
#if 0
/* 'create_empty_fragment' is true only when this function calls itself */
if (!clear && !create_empty_fragment && !s->s3->empty_fragment_done
&& SSL_version(s) != DTLS1_VERSION && SSL_version(s) != DTLS1_BAD_VER)
{
/* countermeasure against known-IV weakness in CBC ciphersuites
* (see http://www.openssl.org/~bodo/tls-cbc.txt)
*/
if (s->s3->need_empty_fragments && type == SSL3_RT_APPLICATION_DATA)
{
/* recursive function call with 'create_empty_fragment' set;
* this prepares and buffers the data for an empty fragment
* (these 'prefix_len' bytes are sent out later
* together with the actual payload) */
prefix_len = s->method->do_ssl_write(s, type, buf, 0, 1);
if (prefix_len <= 0)
goto err;
if (s->s3->wbuf.len < (size_t)prefix_len + SSL3_RT_MAX_PACKET_SIZE)
{
/* insufficient space */
SSLerr(SSL_F_DO_DTLS1_WRITE, ERR_R_INTERNAL_ERROR);
goto err;
}
}
s->s3->empty_fragment_done = 1;
}
#endif
p = wb->buf + prefix_len;
/* write the header */
*(p++)=type&0xff;
wr->type=type;
/* Special case: for hello verify request, client version 1.0 and
* we haven't decided which version to use yet send back using
* version 1.0 header: otherwise some clients will ignore it.
*/
if (s->method->version == DTLS_ANY_VERSION)
{
*(p++)=DTLS1_VERSION>>8;
*(p++)=DTLS1_VERSION&0xff;
}
else
{
*(p++)=s->version>>8;
*(p++)=s->version&0xff;
}
/* field where we are to write out packet epoch, seq num and len */
pseq=p;
p+=10;
/* Explicit IV length, block ciphers appropriate version flag */
if (s->enc_write_ctx)
{
int mode = EVP_CIPHER_CTX_mode(s->enc_write_ctx);
if (mode == EVP_CIPH_CBC_MODE)
{
eivlen = EVP_CIPHER_CTX_iv_length(s->enc_write_ctx);
if (eivlen <= 1)
eivlen = 0;
}
/* Need explicit part of IV for GCM mode */
else if (mode == EVP_CIPH_GCM_MODE)
eivlen = EVP_GCM_TLS_EXPLICIT_IV_LEN;
else
eivlen = 0;
}
else
eivlen = 0;
/* lets setup the record stuff. */
wr->data=p + eivlen; /* make room for IV in case of CBC */
wr->length=(int)len;
wr->input=(unsigned char *)buf;
/* we now 'read' from wr->input, wr->length bytes into
* wr->data */
/* first we compress */
if (s->compress != NULL)
{
if (!ssl3_do_compress(s))
{
SSLerr(SSL_F_DO_DTLS1_WRITE,SSL_R_COMPRESSION_FAILURE);
goto err;
}
}
else
{
memcpy(wr->data,wr->input,wr->length);
wr->input=wr->data;
}
/* we should still have the output to wr->data and the input
* from wr->input. Length should be wr->length.
* wr->data still points in the wb->buf */
if (mac_size != 0)
{
if(s->method->ssl3_enc->mac(s,&(p[wr->length + eivlen]),1) < 0)
goto err;
wr->length+=mac_size;
}
/* this is true regardless of mac size */
wr->input=p;
wr->data=p;
if (eivlen)
wr->length += eivlen;
s->method->ssl3_enc->enc(s,1);
/* record length after mac and block padding */
/* if (type == SSL3_RT_APPLICATION_DATA ||
(type == SSL3_RT_ALERT && ! SSL_in_init(s))) */
/* there's only one epoch between handshake and app data */
s2n(s->d1->w_epoch, pseq);
/* XDTLS: ?? */
/* else
s2n(s->d1->handshake_epoch, pseq); */
memcpy(pseq, &(s->s3->write_sequence[2]), 6);
pseq+=6;
s2n(wr->length,pseq);
if (s->msg_callback)
s->msg_callback(1, 0, SSL3_RT_HEADER, pseq - DTLS1_RT_HEADER_LENGTH, DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
/* we should now have
* wr->data pointing to the encrypted data, which is
* wr->length long */
wr->type=type; /* not needed but helps for debugging */
wr->length+=DTLS1_RT_HEADER_LENGTH;
#if 0 /* this is now done at the message layer */
/* buffer the record, making it easy to handle retransmits */
if ( type == SSL3_RT_HANDSHAKE || type == SSL3_RT_CHANGE_CIPHER_SPEC)
dtls1_buffer_record(s, wr->data, wr->length,
*((PQ_64BIT *)&(s->s3->write_sequence[0])));
#endif
ssl3_record_sequence_update(&(s->s3->write_sequence[0]));
if (create_empty_fragment)
{
/* we are in a recursive call;
* just return the length, don't write out anything here
*/
return wr->length;
}
/* now let's set up wb */
wb->left = prefix_len + wr->length;
wb->offset = 0;
/* memorize arguments so that ssl3_write_pending can detect bad write retries later */
s->s3->wpend_tot=len;
s->s3->wpend_buf=buf;
s->s3->wpend_type=type;
s->s3->wpend_ret=len;
/* we now just need to write the buffer */
return ssl3_write_pending(s,type,buf,len);
err:
return -1;
}
static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap)
{
int cmp;
unsigned int shift;
const unsigned char *seq = s->s3->read_sequence;
cmp = satsub64be(seq,bitmap->max_seq_num);
if (cmp > 0)
{
memcpy (s->s3->rrec.seq_num,seq,8);
return 1; /* this record in new */
}
shift = -cmp;
if (shift >= sizeof(bitmap->map)*8)
return 0; /* stale, outside the window */
else if (bitmap->map & (1UL<<shift))
return 0; /* record previously received */
memcpy (s->s3->rrec.seq_num,seq,8);
return 1;
}
static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap)
{
int cmp;
unsigned int shift;
const unsigned char *seq = s->s3->read_sequence;
cmp = satsub64be(seq,bitmap->max_seq_num);
if (cmp > 0)
{
shift = cmp;
if (shift < sizeof(bitmap->map)*8)
bitmap->map <<= shift, bitmap->map |= 1UL;
else
bitmap->map = 1UL;
memcpy(bitmap->max_seq_num,seq,8);
}
else {
shift = -cmp;
if (shift < sizeof(bitmap->map)*8)
bitmap->map |= 1UL<<shift;
}
}
int dtls1_dispatch_alert(SSL *s)
{
int i,j;
void (*cb)(const SSL *ssl,int type,int val)=NULL;
unsigned char buf[DTLS1_AL_HEADER_LENGTH];
unsigned char *ptr = &buf[0];
s->s3->alert_dispatch=0;
memset(buf, 0x00, sizeof(buf));
*ptr++ = s->s3->send_alert[0];
*ptr++ = s->s3->send_alert[1];
#ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
if (s->s3->send_alert[1] == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE)
{
s2n(s->d1->handshake_read_seq, ptr);
#if 0
if ( s->d1->r_msg_hdr.frag_off == 0) /* waiting for a new msg */
else
s2n(s->d1->r_msg_hdr.seq, ptr); /* partial msg read */
#endif
#if 0
fprintf(stderr, "s->d1->handshake_read_seq = %d, s->d1->r_msg_hdr.seq = %d\n",s->d1->handshake_read_seq,s->d1->r_msg_hdr.seq);
#endif
l2n3(s->d1->r_msg_hdr.frag_off, ptr);
}
#endif
i = do_dtls1_write(s, SSL3_RT_ALERT, &buf[0], sizeof(buf), 0);
if (i <= 0)
{
s->s3->alert_dispatch=1;
/* fprintf( stderr, "not done with alert\n" ); */
}
else
{
if (s->s3->send_alert[0] == SSL3_AL_FATAL
#ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
|| s->s3->send_alert[1] == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
#endif
)
(void)BIO_flush(s->wbio);
if (s->msg_callback)
s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert,
2, s, s->msg_callback_arg);
if (s->info_callback != NULL)
cb=s->info_callback;
else if (s->ctx->info_callback != NULL)
cb=s->ctx->info_callback;
if (cb != NULL)
{
j=(s->s3->send_alert[0]<<8)|s->s3->send_alert[1];
cb(s,SSL_CB_WRITE_ALERT,j);
}
}
return(i);
}
static DTLS1_BITMAP *
dtls1_get_bitmap(SSL *s, SSL3_RECORD *rr, unsigned int *is_next_epoch)
{
*is_next_epoch = 0;
/* In current epoch, accept HM, CCS, DATA, & ALERT */
if (rr->epoch == s->d1->r_epoch)
return &s->d1->bitmap;
/* Only HM and ALERT messages can be from the next epoch */
else if (rr->epoch == (unsigned long)(s->d1->r_epoch + 1) &&
(rr->type == SSL3_RT_HANDSHAKE ||
rr->type == SSL3_RT_ALERT))
{
*is_next_epoch = 1;
return &s->d1->next_bitmap;
}
return NULL;
}
#if 0
static int
dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr, unsigned short *priority,
unsigned long *offset)
{
/* alerts are passed up immediately */
if ( rr->type == SSL3_RT_APPLICATION_DATA ||
rr->type == SSL3_RT_ALERT)
return 0;
/* Only need to buffer if a handshake is underway.
* (this implies that Hello Request and Client Hello are passed up
* immediately) */
if ( SSL_in_init(s))
{
unsigned char *data = rr->data;
/* need to extract the HM/CCS sequence number here */
if ( rr->type == SSL3_RT_HANDSHAKE ||
rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
{
unsigned short seq_num;
struct hm_header_st msg_hdr;
struct ccs_header_st ccs_hdr;
if ( rr->type == SSL3_RT_HANDSHAKE)
{
dtls1_get_message_header(data, &msg_hdr);
seq_num = msg_hdr.seq;
*offset = msg_hdr.frag_off;
}
else
{
dtls1_get_ccs_header(data, &ccs_hdr);
seq_num = ccs_hdr.seq;
*offset = 0;
}
/* this is either a record we're waiting for, or a
* retransmit of something we happened to previously
* receive (higher layers will drop the repeat silently */
if ( seq_num < s->d1->handshake_read_seq)
return 0;
if (rr->type == SSL3_RT_HANDSHAKE &&
seq_num == s->d1->handshake_read_seq &&
msg_hdr.frag_off < s->d1->r_msg_hdr.frag_off)
return 0;
else if ( seq_num == s->d1->handshake_read_seq &&
(rr->type == SSL3_RT_CHANGE_CIPHER_SPEC ||
msg_hdr.frag_off == s->d1->r_msg_hdr.frag_off))
return 0;
else
{
*priority = seq_num;
return 1;
}
}
else /* unknown record type */
return 0;
}
return 0;
}
#endif
void
dtls1_reset_seq_numbers(SSL *s, int rw)
{
unsigned char *seq;
unsigned int seq_bytes = sizeof(s->s3->read_sequence);
if ( rw & SSL3_CC_READ)
{
seq = s->s3->read_sequence;
s->d1->r_epoch++;
memcpy(&(s->d1->bitmap), &(s->d1->next_bitmap), sizeof(DTLS1_BITMAP));
memset(&(s->d1->next_bitmap), 0x00, sizeof(DTLS1_BITMAP));
}
else
{
seq = s->s3->write_sequence;
memcpy(s->d1->last_write_sequence, seq, sizeof(s->s3->write_sequence));
s->d1->w_epoch++;
}
memset(seq, 0x00, seq_bytes);
}
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