/* 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 #include #include #include #include #include #include #include #include #include "internal.h" static int do_dtls1_write(SSL *s, int type, const uint8_t *buf, unsigned int len, enum dtls1_use_epoch_t use_epoch); /* dtls1_get_record reads a new input record. On success, it places it in * |ssl->s3->rrec| and returns one. Otherwise it returns <= 0 on error or if * more data is needed. */ static int dtls1_get_record(SSL *ssl) { again: /* Read a new packet if there is no unconsumed one. */ if (ssl_read_buffer_len(ssl) == 0) { int ret = ssl_read_buffer_extend_to(ssl, 0 /* unused */); if (ret <= 0) { return ret; } } assert(ssl_read_buffer_len(ssl) > 0); /* Ensure the packet is large enough to decrypt in-place. */ if (ssl_read_buffer_len(ssl) < ssl_record_prefix_len(ssl)) { ssl_read_buffer_clear(ssl); goto again; } uint8_t *out = ssl_read_buffer(ssl) + ssl_record_prefix_len(ssl); size_t max_out = ssl_read_buffer_len(ssl) - ssl_record_prefix_len(ssl); uint8_t type, alert; size_t len, consumed; switch (dtls_open_record(ssl, &type, out, &len, &consumed, &alert, max_out, ssl_read_buffer(ssl), ssl_read_buffer_len(ssl))) { case ssl_open_record_success: ssl_read_buffer_consume(ssl, consumed); if (len > 0xffff) { OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW); return -1; } SSL3_RECORD *rr = &ssl->s3->rrec; rr->type = type; rr->length = (uint16_t)len; rr->off = 0; rr->data = out; return 1; case ssl_open_record_discard: ssl_read_buffer_consume(ssl, consumed); goto again; case ssl_open_record_error: ssl3_send_alert(ssl, SSL3_AL_FATAL, alert); return -1; case ssl_open_record_partial: /* Impossible in DTLS. */ break; } assert(0); OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return -1; } int dtls1_read_app_data(SSL *ssl, uint8_t *buf, int len, int peek) { return dtls1_read_bytes(ssl, SSL3_RT_APPLICATION_DATA, buf, len, peek); } void dtls1_read_close_notify(SSL *ssl) { /* Bidirectional shutdown doesn't make sense for an unordered transport. DTLS * alerts also aren't delivered reliably, so we may even time out because the * peer never received our close_notify. Report to the caller that the channel * has fully shut down. */ ssl->shutdown |= SSL_RECEIVED_SHUTDOWN; } /* 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) * * 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 type, int value) = NULL; if ((type != SSL3_RT_APPLICATION_DATA && type != SSL3_RT_HANDSHAKE) || (peek && type != SSL3_RT_APPLICATION_DATA)) { OPENSSL_PUT_ERROR(SSL, 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, 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; /* Check for timeout */ if (DTLSv1_handle_timeout(s) > 0) { goto start; } /* get new packet if necessary */ if (rr->length == 0) { 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. DTLS is unreliable, so drop the * packet and expect the peer to retransmit. */ 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, SSL_R_APP_DATA_IN_HANDSHAKE); goto f_err; } /* Discard empty records. */ if (rr->length == 0) { goto start; } 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) { rr->off = 0; /* The record has been consumed, so we may now clear the buffer. */ ssl_read_buffer_discard(s); } } 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, 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, 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, SSL_R_UNKNOWN_ALERT_TYPE); goto f_err; } goto start; } 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, 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, 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, SSL_R_UNEXPECTED_RECORD); f_err: ssl3_send_alert(s, SSL3_AL_FATAL, al); err: return -1; } int dtls1_write_app_data(SSL *s, 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, SSL_R_SSL_HANDSHAKE_FAILURE); return -1; } } if (len > SSL3_RT_MAX_PLAIN_LENGTH) { OPENSSL_PUT_ERROR(SSL, SSL_R_DTLS_MESSAGE_TOO_BIG); return -1; } i = dtls1_write_bytes(s, SSL3_RT_APPLICATION_DATA, buf_, len, dtls1_use_current_epoch); 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, enum dtls1_use_epoch_t use_epoch) { int i; assert(len <= SSL3_RT_MAX_PLAIN_LENGTH); s->rwstate = SSL_NOTHING; i = do_dtls1_write(s, type, buf, len, use_epoch); return i; } static int do_dtls1_write(SSL *s, int type, const uint8_t *buf, unsigned int len, enum dtls1_use_epoch_t use_epoch) { /* ssl3_write_pending drops the write if |BIO_write| fails in DTLS, so there * is never pending data. */ assert(!ssl_write_buffer_is_pending(s)); /* If we have an alert to send, lets send it */ if (s->s3->alert_dispatch) { int ret = s->method->ssl_dispatch_alert(s); if (ret <= 0) { return ret; } /* if it went, fall through and send more stuff */ } if (len > SSL3_RT_MAX_PLAIN_LENGTH) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return -1; } if (len == 0) { return 0; } size_t max_out = len + ssl_max_seal_overhead(s); uint8_t *out; size_t ciphertext_len; if (!ssl_write_buffer_init(s, &out, max_out) || !dtls_seal_record(s, out, &ciphertext_len, max_out, type, buf, len, use_epoch)) { return -1; } ssl_write_buffer_set_len(s, ciphertext_len); /* 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); } int dtls1_dispatch_alert(SSL *s) { int i, j; void (*cb)(const SSL *ssl, int type, int value) = 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), dtls1_use_current_epoch); 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; } 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++; memset(&s->d1->bitmap, 0, 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); }