kris/boringssl
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
dc3da93899
boringssl/ssl/d1_pkt.c
David Benjamin dc3da93899 Process alerts between ChangeCipherSpec and Finished. 
This mostly[*] doesn't matter for TLS since the message would have been
rejected anyway, but, in DTLS, if the peer rejects our Finished, it will send
an encrypted alert. This will then cause it to hang, which isn't very helpful.

I've made the change on both TLS and DTLS so the two protocols don't diverge on
this point. It is true that we're accepting nominally encrypted and
authenticated alerts before Finished, but, prior to ChangeCipherSpec, the
alerts are sent in the clear anyway so an attacker could already inject alerts.
A consumer could only be sensitive to it being post-CCS if it was watching
msg_callback. The only non-debug consumer of msg_callback I've found anywhere
is some hostapd code to detect Heartbeat.

See https://code.google.com/p/webrtc/issues/detail?id=4403 for an instance
where the equivalent behavior in OpenSSL masks an alert.

[*] This does change behavior slightly if the peer sends a warning alert
between CCS and Finished. I believe this is benign as warning alerts are
usually ignored apart from info_callback and msg_callback. The one exception is
a close_notify which is a slightly new state (accepting close_notify during a
handshake seems questionable...), but they're processed pre-CCS too.

Change-Id: Idd0d49b9f9aa9d35374a9f5e2f815cdb931f5254
Reviewed-on: https://boringssl-review.googlesource.com/3883
Reviewed-by: Adam Langley <agl@google.com>
2015-03-13 20:19:11 +00:00

1135 lines
34 KiB
C
Raw Blame History

/* 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>
#include <assert.h>
#include <openssl/buf.h>
#include <openssl/mem.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/rand.h>
#include "ssl_locl.h"
/* mod 128 saturating subtract of two 64-bit values in big-endian order */
static int satsub64be(const uint8_t *v1, const uint8_t *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 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);
static int dtls1_buffer_record(SSL *s, record_pqueue *q,
uint8_t *priority);
static int dtls1_process_record(SSL *s);
static int do_dtls1_write(SSL *s, int type, const uint8_t *buf,
unsigned int len);
/* 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,
uint8_t *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);
}
OPENSSL_PUT_ERROR(SSL, dtls1_buffer_record, ERR_R_INTERNAL_ERROR);
return -1;
}
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;
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)) {
goto internal_error;
}
/* insert should not fail, since duplicates are dropped */
if (pqueue_insert(queue->q, item) == NULL) {
goto internal_error;
}
return 1;
internal_error:
OPENSSL_PUT_ERROR(SSL, dtls1_buffer_record, ERR_R_INTERNAL_ERROR);
if (rdata->rbuf.buf != NULL) {
OPENSSL_free(rdata->rbuf.buf);
}
OPENSSL_free(rdata);
pitem_free(item);
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, i.e.,
* 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;
}
if (dtls1_buffer_record(s, &(s->d1->processed_rcds),
s->s3->rrec.seq_num) < 0) {
return -1;
}
}
}
/* 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;
}
static int dtls1_process_record(SSL *s) {
int al;
SSL3_RECORD *rr;
rr = &(s->s3->rrec);
/* 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;
OPENSSL_PUT_ERROR(SSL, dtls1_process_record,
SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
goto f_err;
}
/* decrypt in place in 'rr->input' */
rr->data = rr->input;
if (!s->enc_method->enc(s, 0)) {
/* Bad packets are silently dropped in DTLS. Clear the error queue of any
* errors decryption may have added. */
ERR_clear_error();
rr->length = 0;
s->packet_length = 0;
goto err;
}
if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH) {
al = SSL_AD_RECORD_OVERFLOW;
OPENSSL_PUT_ERROR(SSL, 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;
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. */
if (dtls1_process_buffered_records(s) < 0) {
return -1;
}
/* 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->s3->have_version) {
if (version != s->version) {
/* The record's version doesn't match, so silently drop it.
*
* TODO(davidben): This doesn't work. The DTLS record layer is not
* packet-based, so the remainder of the packet isn't dropped and we
* get a framing error. It's also unclear what it means to silently
* drop a record in a packet containing two records. */
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 */
}
/* Check whether this is a repeat, or aged record. */
if (!dtls1_record_replay_check(s, bitmap)) {
rr->length = 0;
s->packet_length = 0; /* dump this record */
goto again; /* get another record */
}
/* 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.
*/
if (is_next_epoch) {
if (SSL_in_init(s) || s->in_handshake) {
if (dtls1_buffer_record(s, &(s->d1->unprocessed_rcds), rr->seq_num) < 0) {
return -1;
}
dtls1_record_bitmap_update(s, bitmap); /* Mark receipt of record. */
}
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 */
}
dtls1_record_bitmap_update(s, bitmap); /* Mark receipt of 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, ret;
unsigned int n;
SSL3_RECORD *rr;
void (*cb)(const SSL *ssl, int type2, int val) = NULL;
/* 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))) {
OPENSSL_PUT_ERROR(SSL, dtls1_read_bytes, ERR_R_INTERNAL_ERROR);
return -1;
}
if (!s->in_handshake && SSL_in_init(s)) {
/* type == SSL3_RT_APPLICATION_DATA */
i = s->handshake_func(s);
if (i < 0) {
return i;
}
if (i == 0) {
OPENSSL_PUT_ERROR(SSL, dtls1_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE);
return -1;
}
}
if (s->s3->rbuf.buf == NULL && !ssl3_setup_buffers(s)) {
/* TODO(davidben): Is this redundant with the calls in the handshake? */
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) {
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;
}
}
}
/* we now have a packet which can be read and processed */
/* |change_cipher_spec is set when we receive a ChangeCipherSpec and reset by
* ssl3_get_finished. */
if (s->s3->change_cipher_spec && rr->type != SSL3_RT_HANDSHAKE &&
rr->type != SSL3_RT_ALERT) {
/* We now have an unexpected record 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. */
if (dtls1_buffer_record(s, &(s->d1->buffered_app_data), rr->seq_num) < 0) {
OPENSSL_PUT_ERROR(SSL, dtls1_read_bytes, ERR_R_INTERNAL_ERROR);
return -1;
}
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->aead_read_ctx == NULL)) {
/* TODO(davidben): Is this check redundant with the handshake_func
* check? */
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, 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;
}
}
return n;
}
/* If we get here, then type != rr->type. */
/* If an alert record, process one alert out of the record. Note that we allow
* a single record to contain multiple alerts. */
if (rr->type == SSL3_RT_ALERT) {
/* Alerts may not be fragmented. */
if (rr->length < 2) {
al = SSL_AD_DECODE_ERROR;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_ALERT);
goto f_err;
}
if (s->msg_callback) {
s->msg_callback(0, s->version, SSL3_RT_ALERT, &rr->data[rr->off], 2, s,
s->msg_callback_arg);
}
const uint8_t alert_level = rr->data[rr->off++];
const uint8_t alert_descr = rr->data[rr->off++];
rr->length -= 2;
if (s->info_callback != NULL) {
cb = s->info_callback;
} else if (s->ctx->info_callback != NULL) {
cb = s->ctx->info_callback;
}
if (cb != NULL) {
uint16_t alert = (alert_level << 8) | alert_descr;
cb(s, SSL_CB_READ_ALERT, alert);
}
if (alert_level == SSL3_AL_WARNING) {
s->s3->warn_alert = alert_descr;
if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
s->shutdown |= SSL_RECEIVED_SHUTDOWN;
return 0;
}
} else if (alert_level == SSL3_AL_FATAL) {
char tmp[16];
s->rwstate = SSL_NOTHING;
s->s3->fatal_alert = alert_descr;
OPENSSL_PUT_ERROR(SSL, 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;
OPENSSL_PUT_ERROR(SSL, 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) {
/* 'Change Cipher Spec' is just a single byte, so we know exactly what the
* record payload has to look like */
if (rr->length != 1 || rr->off != 0 || rr->data[0] != SSL3_MT_CCS) {
al = SSL_AD_ILLEGAL_PARAMETER;
OPENSSL_PUT_ERROR(SSL, dtls1_read_bytes, SSL_R_BAD_CHANGE_CIPHER_SPEC);
goto f_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);
goto start;
}
/* Unexpected handshake message. It may be a retransmitted Finished (the only
* post-CCS message). Otherwise, it's a pre-CCS handshake message from an
* unsupported renegotiation attempt. */
if (rr->type == SSL3_RT_HANDSHAKE && !s->in_handshake) {
if (rr->length < DTLS1_HM_HEADER_LENGTH) {
al = SSL_AD_DECODE_ERROR;
OPENSSL_PUT_ERROR(SSL, ssl3_read_bytes, SSL_R_BAD_HANDSHAKE_RECORD);
goto f_err;
}
struct hm_header_st msg_hdr;
dtls1_get_message_header(&rr->data[rr->off], &msg_hdr);
/* Ignore a stray Finished from the previous handshake. */
if (msg_hdr.type == SSL3_MT_FINISHED) {
if (msg_hdr.frag_off == 0) {
/* Retransmit our last flight of messages. If the peer sends the second
* Finished, they may not have received ours. Only do this for the
* first fragment, in case the Finished was fragmented. */
if (dtls1_check_timeout_num(s) < 0) {
return -1;
}
dtls1_retransmit_buffered_messages(s);
}
rr->length = 0;
goto start;
}
}
/* We already handled these. */
assert(rr->type != SSL3_RT_CHANGE_CIPHER_SPEC && rr->type != SSL3_RT_ALERT);
al = SSL_AD_UNEXPECTED_MESSAGE;
OPENSSL_PUT_ERROR(SSL, dtls1_read_bytes, SSL_R_UNEXPECTED_RECORD);
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;
if (SSL_in_init(s) && !s->in_handshake) {
i = s->handshake_func(s);
if (i < 0) {
return i;
}
if (i == 0) {
OPENSSL_PUT_ERROR(SSL, dtls1_write_app_data_bytes,
SSL_R_SSL_HANDSHAKE_FAILURE);
return -1;
}
}
if (len > SSL3_RT_MAX_PLAIN_LENGTH) {
OPENSSL_PUT_ERROR(SSL, dtls1_write_app_data_bytes,
SSL_R_DTLS_MESSAGE_TOO_BIG);
return -1;
}
i = dtls1_write_bytes(s, type, buf_, len);
return i;
}
/* 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;
assert(len <= SSL3_RT_MAX_PLAIN_LENGTH);
s->rwstate = SSL_NOTHING;
i = do_dtls1_write(s, type, buf, len);
return i;
}
static int do_dtls1_write(SSL *s, int type, const uint8_t *buf,
unsigned int len) {
uint8_t *p, *pseq;
int i;
int prefix_len = 0;
int eivlen = 0;
SSL3_RECORD *wr;
SSL3_BUFFER *wb;
/* 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) {
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) {
return 0;
}
wr = &(s->s3->wrec);
wb = &(s->s3->wbuf);
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->s3->have_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;
/* Leave room for the variable nonce for AEADs which specify it explicitly. */
if (s->aead_write_ctx != NULL &&
s->aead_write_ctx->variable_nonce_included_in_record) {
eivlen = s->aead_write_ctx->variable_nonce_len;
}
/* 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 */
memcpy(wr->data, wr->input, wr->length);
wr->input = wr->data;
/* this is true regardless of mac size */
wr->input = p;
wr->data = p;
wr->length += eivlen;
if (!s->enc_method->enc(s, 1)) {
goto err;
}
/* there's only one epoch between handshake and app data */
s2n(s->d1->w_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;
ssl3_record_sequence_update(&(s->s3->write_sequence[0]));
/* 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 uint8_t *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 & (((uint64_t)1) << 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 uint8_t *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 |= ((uint64_t)1) << shift;
}
}
}
int dtls1_dispatch_alert(SSL *s) {
int i, j;
void (*cb)(const SSL *ssl, int type, int val) = NULL;
uint8_t buf[DTLS1_AL_HEADER_LENGTH];
uint8_t *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];
i = do_dtls1_write(s, SSL3_RT_ALERT, &buf[0], sizeof(buf));
if (i <= 0) {
s->s3->alert_dispatch = 1;
} else {
if (s->s3->send_alert[0] == SSL3_AL_FATAL) {
(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;
} else if (rr->epoch == (unsigned long)(s->d1->r_epoch + 1) &&
(rr->type == SSL3_RT_HANDSHAKE || rr->type == SSL3_RT_ALERT)) {
/* Only HM and ALERT messages can be from the next epoch */
*is_next_epoch = 1;
return &s->d1->next_bitmap;
}
return NULL;
}
void dtls1_reset_seq_numbers(SSL *s, int rw) {
uint8_t *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);
}
Reference in New Issue View Git Blame Copy Permalink