/* 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 "ssl_locl.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); static int do_dtls1_write(SSL *s, int type, const unsigned char *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, 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); OPENSSL_PUT_ERROR(SSL, 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; 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)) { OPENSSL_PUT_ERROR(SSL, dtls1_buffer_record, ERR_R_INTERNAL_ERROR); OPENSSL_free(rdata); pitem_free(item); return(0); } /* insert should not fail, since duplicates are dropped */ if (pqueue_insert(queue->q, item) == NULL) { OPENSSL_PUT_ERROR(SSL, 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, orig_len; 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; 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; 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; zlength; 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); assert(mac_size <= EVP_MAX_MD_SIZE); /* kludge: *_cbc_remove_padding passes padding length in rr->type */ orig_len = rr->length+((unsigned int)rr->type>>8); /* 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 (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 && orig_len < mac_size+1)) { al=SSL_AD_DECODE_ERROR; OPENSSL_PUT_ERROR(SSL, 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, orig_len); rr->length -= mac_size; } else { /* In this case there's no padding, so |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; } 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; 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) { /* 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) { 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))) { OPENSSL_PUT_ERROR(SSL, 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. */ 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); } } 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 */ 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; 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 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; } /* 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; OPENSSL_PUT_ERROR(SSL, 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) { 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; OPENSSL_PUT_ERROR(SSL, dtls1_read_bytes, SSL_R_BAD_HELLO_REQUEST); goto f_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) { OPENSSL_PUT_ERROR(SSL, dtls1_read_bytes, SSL_R_SSL_HANDSHAKE_FAILURE); 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) { s->shutdown |= SSL_RECEIVED_SHUTDOWN; return(0); } } else if (alert_level == 2) /* 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) { struct ccs_header_st ccs_hdr; unsigned int ccs_hdr_len = DTLS1_CCS_HEADER_LENGTH; dtls1_get_ccs_header(rr->data, &ccs_hdr); /* '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)) { 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 (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)) { s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT; s->renegotiate=1; s->new_session=1; } 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); } goto start; } switch (rr->type) { default: /* TLS just ignores unknown message types */ if (s->version == TLS1_VERSION) { rr->length = 0; goto start; } al=SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, 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; OPENSSL_PUT_ERROR(SSL, 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; OPENSSL_PUT_ERROR(SSL, 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; 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; } /* 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; 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 unsigned char *buf, unsigned int len) { 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) { 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); 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; } 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 */ 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])); /* 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 & (((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 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 |= ((uint64_t) 1) << 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]; i = do_dtls1_write(s, SSL3_RT_ALERT, &buf[0], sizeof(buf)); 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) (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); }