static int dtls1_buffer_record(SSL *s, record_pqueue *q,
unsigned char *priority);
static int dtls1_process_record(SSL *s);
-static void dtls1_clear_timeouts(SSL *s);
/* copy buffered record into SSL structure */
static int
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);
}
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)
item = pqueue_peek(s->d1->unprocessed_rcds.q);
if (item)
{
- DTLS1_RECORD_DATA *rdata;
- rdata = (DTLS1_RECORD_DATA *)item->data;
-
/* Check if epoch is current. */
if (s->d1->unprocessed_rcds.epoch != s->d1->r_epoch)
return(1); /* Nothing to do. */
SSL3_RECORD *rr;
unsigned int mac_size;
unsigned char md[EVP_MAX_MD_SIZE];
+ int decryption_failed_or_bad_record_mac = 0;
+ unsigned char *mac = NULL;
rr= &(s->s3->rrec);
enc_err = s->method->ssl3_enc->enc(s,0);
if (enc_err <= 0)
{
- if (enc_err == 0)
- /* SSLerr() and ssl3_send_alert() have been called */
- goto err;
-
- /* otherwise enc_err == -1 */
- goto decryption_failed_or_bad_record_mac;
+ /* To minimize information leaked via timing, we will always
+ * perform all computations before discarding the message.
+ */
+ decryption_failed_or_bad_record_mac = 1;
}
#ifdef TLS_DEBUG
if ( (sess == NULL) ||
(s->enc_read_ctx == NULL) ||
(s->read_hash == NULL))
- clear=1;
+ clear=1;
if (!clear)
{
- mac_size=EVP_MD_CTX_size(s->read_hash);
+ /* !clear => s->read_hash != NULL => mac_size != -1 */
+ int t;
+ t=EVP_MD_CTX_size(s->read_hash);
+ OPENSSL_assert(t >= 0);
+ mac_size=t;
if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
{
SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
goto f_err;
#else
- goto decryption_failed_or_bad_record_mac;
+ decryption_failed_or_bad_record_mac = 1;
#endif
}
/* check the MAC for rr->input (it's in mac_size bytes at the tail) */
- if (rr->length < mac_size)
+ if (rr->length >= mac_size)
{
-#if 0 /* OK only for stream ciphers */
- al=SSL_AD_DECODE_ERROR;
- SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
- goto f_err;
-#else
- goto decryption_failed_or_bad_record_mac;
-#endif
+ rr->length -= mac_size;
+ mac = &rr->data[rr->length];
}
- rr->length-=mac_size;
+ else
+ rr->length = 0;
i=s->method->ssl3_enc->mac(s,md,0);
- if (memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
+ if (i < 0 || mac == NULL || CRYPTO_memcmp(md,mac,mac_size) != 0)
{
- goto decryption_failed_or_bad_record_mac;
+ decryption_failed_or_bad_record_mac = 1;
}
}
+ if (decryption_failed_or_bad_record_mac)
+ {
+ /* decryption failed, silently discard message */
+ rr->length = 0;
+ s->packet_length = 0;
+ goto err;
+ }
+
/* r->length is now just compressed */
if (s->expand != NULL)
{
dtls1_record_bitmap_update(s, &(s->d1->bitmap));/* Mark receipt of record. */
return(1);
-decryption_failed_or_bad_record_mac:
- /* Separate 'decryption_failed' alert was introduced with TLS 1.0,
- * SSL 3.0 only has 'bad_record_mac'. But unless a decryption
- * failure is directly visible from the ciphertext anyway,
- * we should not reveal which kind of error occured -- this
- * might become visible to an attacker (e.g. via logfile) */
- al=SSL_AD_BAD_RECORD_MAC;
- SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
f_err:
ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
/* used only by dtls1_read_bytes */
int dtls1_get_record(SSL *s)
{
- int ssl_major,ssl_minor,al;
+ int ssl_major,ssl_minor;
int i,n;
SSL3_RECORD *rr;
- SSL_SESSION *sess;
- unsigned char *p;
+ unsigned char *p = NULL;
unsigned short version;
DTLS1_BITMAP *bitmap;
unsigned int is_next_epoch;
rr= &(s->s3->rrec);
- sess=s->session;
/* The epoch may have changed. If so, process all the
* pending records. This is a non-blocking operation. */
- if ( ! dtls1_process_buffered_records(s))
- return 0;
+ dtls1_process_buffered_records(s);
/* if we're renegotiating, then there may be buffered records */
if (dtls1_get_processed_record(s))
/* read timeout is handled by dtls1_read_bytes */
if (n <= 0) return(n); /* error or non-blocking */
- OPENSSL_assert(s->packet_length == DTLS1_RT_HEADER_LENGTH);
+ /* 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;
{
if (version != s->version)
{
- SSLerr(SSL_F_DTLS1_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
- /* Send back error using their
- * version number :-) */
- s->version=version;
- al=SSL_AD_PROTOCOL_VERSION;
- goto f_err;
+ /* unexpected version, silently discard */
+ rr->length = 0;
+ s->packet_length = 0;
+ goto again;
}
}
- if ((version & 0xff00) != (DTLS1_VERSION & 0xff00))
+ if ((version & 0xff00) != (s->version & 0xff00))
{
- SSLerr(SSL_F_DTLS1_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
- goto err;
+ /* wrong version, silently discard record */
+ rr->length = 0;
+ s->packet_length = 0;
+ goto again;
}
if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
{
- al=SSL_AD_RECORD_OVERFLOW;
- SSLerr(SSL_F_DTLS1_GET_RECORD,SSL_R_PACKET_LENGTH_TOO_LONG);
- goto f_err;
+ /* record too long, silently discard it */
+ rr->length = 0;
+ s->packet_length = 0;
+ goto again;
}
/* now s->rstate == SSL_ST_READ_BODY */
/* this packet contained a partial record, dump it */
if ( n != i)
{
+ rr->length = 0;
s->packet_length = 0;
goto again;
}
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))
+ /* 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 */
}
if (rr->length == 0) goto again;
/* If this record is from the next epoch (either HM or ALERT),
- * buffer it since it cannot be processed at this time. Records
- * from the next epoch are marked as received even though they
- * are not processed, so as to prevent any potential resource
- * DoS attack */
+ * 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)
{
- dtls1_record_bitmap_update(s, bitmap);
- dtls1_buffer_record(s, &(s->d1->unprocessed_rcds), rr->seq_num);
+ 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))
- return(0);
+ if (!dtls1_process_record(s))
+ {
+ rr->length = 0;
+ s->packet_length = 0; /* dump this record */
+ goto again; /* get another record */
+ }
- dtls1_clear_timeouts(s); /* done waiting */
return(1);
-f_err:
- ssl3_send_alert(s,SSL3_AL_FATAL,al);
-err:
- return(0);
}
/* Return up to 'len' payload bytes received in 'type' records.
* 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))
{
* reset by ssl3_get_finished */
&& (rr->type != SSL3_RT_HANDSHAKE))
{
- al=SSL_AD_UNEXPECTED_MESSAGE;
- SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
- goto err;
+ /* 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
dest = s->d1->alert_fragment;
dest_len = &s->d1->alert_fragment_len;
}
- /* else it's a CCS message, or it's wrong */
- else if (rr->type != SSL3_RT_CHANGE_CIPHER_SPEC)
- {
- /* 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;
- }
+ /* 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)
{
n2s(p, seq);
n2l3(p, frag_off);
- dtls1_retransmit_message(s, seq, frag_off, &found);
+ 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)); */
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 != DTLS1_CCS_HEADER_LENGTH) ||
+ if ( (rr->length != ccs_hdr_len) ||
(rr->off != 0) || (rr->data[0] != SSL3_MT_CCS))
{
i=SSL_AD_ILLEGAL_PARAMETER;
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++;
+
goto start;
}
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))
{
int
dtls1_write_app_data_bytes(SSL *s, int type, const void *buf_, int len)
{
- unsigned int n,tot;
int i;
if (SSL_in_init(s) && !s->in_handshake)
}
}
- tot = s->s3->wnum;
- n = len - tot;
-
- while( n)
+ if (len > SSL3_RT_MAX_PLAIN_LENGTH)
{
- /* dtls1_write_bytes sends one record at a time, sized according to
- * the currently known MTU */
- i = dtls1_write_bytes(s, type, buf_, len);
- if (i <= 0) return i;
-
- if ((i == (int)n) ||
- (type == SSL3_RT_APPLICATION_DATA &&
- (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE)))
- {
- /* next chunk of data should get another prepended empty fragment
- * in ciphersuites with known-IV weakness: */
- s->s3->empty_fragment_done = 0;
- return tot+i;
- }
-
- tot += i;
- n-=i;
+ SSLerr(SSL_F_DTLS1_WRITE_APP_DATA_BYTES,SSL_R_DTLS_MESSAGE_TOO_BIG);
+ return -1;
}
- return tot;
+ 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 dtls1_write_bytes(SSL *s, int type, const void *buf, int len)
{
- const unsigned char *buf=buf_;
- unsigned int tot,n,nw;
int i;
- unsigned int mtu;
+ OPENSSL_assert(len <= SSL3_RT_MAX_PLAIN_LENGTH);
s->rwstate=SSL_NOTHING;
- tot=s->s3->wnum;
-
- n=(len-tot);
-
- /* handshake layer figures out MTU for itself, but data records
- * are also sent through this interface, so need to figure out MTU */
-#if 0
- mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_MTU, 0, NULL);
- mtu += DTLS1_HM_HEADER_LENGTH; /* HM already inserted */
-#endif
- mtu = s->d1->mtu;
-
- if (mtu > SSL3_RT_MAX_PLAIN_LENGTH)
- mtu = SSL3_RT_MAX_PLAIN_LENGTH;
-
- if (n > mtu)
- nw=mtu;
- else
- nw=n;
-
- i=do_dtls1_write(s, type, &(buf[tot]), nw, 0);
- if (i <= 0)
- {
- s->s3->wnum=tot;
- return i;
- }
-
- if ( (int)s->s3->wnum + i == len)
- s->s3->wnum = 0;
- else
- s->s3->wnum += i;
-
- return tot + i;
+ 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)
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_VERSION && SSL_version(s) != DTLS1_BAD_VER)
{
/* countermeasure against known-IV weakness in CBC ciphersuites
* (see http://www.openssl.org/~bodo/tls-cbc.txt)
s->s3->empty_fragment_done = 1;
}
#endif
-
p = wb->buf + prefix_len;
/* write the header */
if (mac_size != 0)
{
- s->method->ssl3_enc->mac(s,&(p[wr->length + bs]),1);
+ if(s->method->ssl3_enc->mac(s,&(p[wr->length + bs]),1) < 0)
+ goto err;
wr->length+=mac_size;
}
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);
}
-
-
-static void
-dtls1_clear_timeouts(SSL *s)
- {
- memset(&(s->d1->timeout), 0x00, sizeof(struct dtls1_timeout_st));
- }