/* $OpenBSD: d1_pkt.c,v 1.70 2020/03/10 17:02:21 jsing Exp $ */ /* * 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 "ssl_locl.h" #include #include #include "pqueue.h" #include "bytestring.h" static int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len); /* 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 { long l; if (BYTE_ORDER == LITTLE_ENDIAN) 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); static int dtls1_buffer_record(SSL *s, record_pqueue *q, unsigned char *priority); static int dtls1_process_record(SSL *s); /* copy buffered record into SSL structure */ static int dtls1_copy_record(SSL *s, pitem *item) { DTLS1_RECORD_DATA *rdata; rdata = (DTLS1_RECORD_DATA *)item->data; free(S3I(s)->rbuf.buf); s->internal->packet = rdata->packet; s->internal->packet_length = rdata->packet_length; memcpy(&(S3I(s)->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER)); memcpy(&(S3I(s)->rrec), &(rdata->rrec), sizeof(SSL3_RECORD)); /* Set proper sequence number for mac calculation */ memcpy(&(S3I(s)->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 = malloc(sizeof(DTLS1_RECORD_DATA)); item = pitem_new(priority, rdata); if (rdata == NULL || item == NULL) goto init_err; rdata->packet = s->internal->packet; rdata->packet_length = s->internal->packet_length; memcpy(&(rdata->rbuf), &(S3I(s)->rbuf), sizeof(SSL3_BUFFER)); memcpy(&(rdata->rrec), &(S3I(s)->rrec), sizeof(SSL3_RECORD)); item->data = rdata; s->internal->packet = NULL; s->internal->packet_length = 0; memset(&(S3I(s)->rbuf), 0, sizeof(SSL3_BUFFER)); memset(&(S3I(s)->rrec), 0, sizeof(SSL3_RECORD)); if (!ssl3_setup_buffers(s)) goto err; /* insert should not fail, since duplicates are dropped */ if (pqueue_insert(queue->q, item) == NULL) goto err; return (1); err: free(rdata->rbuf.buf); init_err: SSLerror(s, ERR_R_INTERNAL_ERROR); 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); 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), \ &((D1I(s))->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), \ &((D1I(s))->processed_rcds)) static int dtls1_process_buffered_records(SSL *s) { pitem *item; item = pqueue_peek(D1I(s)->unprocessed_rcds.q); if (item) { /* Check if epoch is current. */ if (D1I(s)->unprocessed_rcds.epoch != D1I(s)->r_epoch) return (1); /* Nothing to do. */ /* Process all the records. */ while (pqueue_peek(D1I(s)->unprocessed_rcds.q)) { dtls1_get_unprocessed_record(s); if (! dtls1_process_record(s)) return (0); if (dtls1_buffer_record(s, &(D1I(s)->processed_rcds), S3I(s)->rrec.seq_num) < 0) return (-1); } } /* sync epoch numbers once all the unprocessed records * have been processed */ D1I(s)->processed_rcds.epoch = D1I(s)->r_epoch; D1I(s)->unprocessed_rcds.epoch = D1I(s)->r_epoch + 1; return (1); } 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 = &(S3I(s)->rrec); sess = s->session; /* At this point, s->internal->packet_length == SSL3_RT_HEADER_LNGTH + rr->length, * and we have that many bytes in s->internal->packet */ rr->input = &(s->internal->packet[DTLS1_RT_HEADER_LENGTH]); /* ok, we can now read from 's->internal->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; SSLerror(s, SSL_R_ENCRYPTED_LENGTH_TOO_LONG); goto f_err; } /* decrypt in place in 'rr->input' */ rr->data = rr->input; /* 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 = dtls1_enc(s, 0)) == 0) { /* For DTLS we simply ignore bad packets. */ rr->length = 0; s->internal->packet_length = 0; goto err; } /* r->length is now the compressed data plus mac */ if ((sess != NULL) && (s->enc_read_ctx != NULL) && (EVP_MD_CTX_md(s->read_hash) != NULL)) { /* s->read_hash != NULL => mac_size != -1 */ unsigned char *mac = NULL; unsigned char mac_tmp[EVP_MAX_MD_SIZE]; mac_size = EVP_MD_CTX_size(s->read_hash); OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE); /* 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; SSLerror(s, 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 = tls1_mac(s, md, 0 /* not send */); if (i < 0 || mac == NULL || timingsafe_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->internal->packet_length = 0; goto err; } if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH) { al = SSL_AD_RECORD_OVERFLOW; SSLerror(s, SSL_R_DATA_LENGTH_TOO_LONG); goto f_err; } rr->off = 0; /* So at this point the following is true * ssl->s3->internal->rrec.type is the type of record * ssl->s3->internal->rrec.length == number of bytes in record * ssl->s3->internal->rrec.off == offset to first valid byte * ssl->s3->internal->rrec.data == where to take bytes from, increment * after use :-). */ /* we have pulled in a full packet so zero things */ s->internal->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->internal->rrec.type - is the type of record * ssl->s3->internal->rrec.data, - data * ssl->s3->internal->rrec.length, - number of bytes */ /* used only by dtls1_read_bytes */ int dtls1_get_record(SSL *s) { SSL3_RECORD *rr; unsigned char *p = NULL; DTLS1_BITMAP *bitmap; unsigned int is_next_epoch; int n; rr = &(S3I(s)->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 */ if (0) { again: /* dump this record on all retries */ rr->length = 0; s->internal->packet_length = 0; } /* check if we have the header */ if ((s->internal->rstate != SSL_ST_READ_BODY) || (s->internal->packet_length < DTLS1_RT_HEADER_LENGTH)) { CBS header, seq_no; uint16_t epoch, len, ssl_version; uint8_t type; n = ssl3_packet_read(s, DTLS1_RT_HEADER_LENGTH); if (n <= 0) return (n); /* If this packet contained a partial record, dump it. */ if (n != DTLS1_RT_HEADER_LENGTH) goto again; s->internal->rstate = SSL_ST_READ_BODY; CBS_init(&header, s->internal->packet, s->internal->packet_length); /* Pull apart the header into the DTLS1_RECORD */ if (!CBS_get_u8(&header, &type)) goto again; if (!CBS_get_u16(&header, &ssl_version)) goto again; /* sequence number is 64 bits, with top 2 bytes = epoch */ if (!CBS_get_u16(&header, &epoch) || !CBS_get_bytes(&header, &seq_no, 6)) goto again; if (!CBS_write_bytes(&seq_no, &(S3I(s)->read_sequence[2]), sizeof(S3I(s)->read_sequence) - 2, NULL)) goto again; if (!CBS_get_u16(&header, &len)) goto again; rr->type = type; rr->epoch = epoch; rr->length = len; /* unexpected version, silently discard */ if (!s->internal->first_packet && ssl_version != s->version) goto again; /* wrong version, silently discard record */ if ((ssl_version & 0xff00) != (s->version & 0xff00)) goto again; /* record too long, silently discard it */ if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) goto again; /* now s->internal->rstate == SSL_ST_READ_BODY */ p = (unsigned char *)CBS_data(&header); } /* s->internal->rstate == SSL_ST_READ_BODY, get and decode the data */ n = ssl3_packet_extend(s, DTLS1_RT_HEADER_LENGTH + rr->length); if (n <= 0) return (n); /* If this packet contained a partial record, dump it. */ if (n != DTLS1_RT_HEADER_LENGTH + rr->length) goto again; s->internal->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) goto again; /* * 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 (!(D1I(s)->listen && rr->type == SSL3_RT_HANDSHAKE && p != NULL && *p == SSL3_MT_CLIENT_HELLO) && !dtls1_record_replay_check(s, bitmap)) goto again; /* just read a 0 length packet */ if (rr->length == 0) goto again; /* If this record is from the next epoch (either HM or ALERT), * and a handshake is currently in progress, buffer it since it * cannot be processed at this time. However, do not buffer * anything while listening. */ if (is_next_epoch) { if ((SSL_in_init(s) || s->internal->in_handshake) && !D1I(s)->listen) { if (dtls1_buffer_record(s, &(D1I(s)->unprocessed_rcds), rr->seq_num) < 0) return (-1); /* Mark receipt of record. */ dtls1_record_bitmap_update(s, bitmap); } goto again; } if (!dtls1_process_record(s)) goto again; /* Mark receipt of record. */ dtls1_record_bitmap_update(s, bitmap); 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 (S3I(s)->rbuf.buf == NULL) /* Not initialized yet */ if (!ssl3_setup_buffers(s)) return (-1); if ((type && type != SSL3_RT_APPLICATION_DATA && type != SSL3_RT_HANDSHAKE) || (peek && (type != SSL3_RT_APPLICATION_DATA))) { SSLerror(s, 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 D1I(s)->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */ if (!s->internal->in_handshake && SSL_in_init(s)) { /* type == SSL3_RT_APPLICATION_DATA */ i = s->internal->handshake_func(s); if (i < 0) return (i); if (i == 0) { SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE); return (-1); } } start: s->internal->rwstate = SSL_NOTHING; /* S3I(s)->rrec.type - is the type of record * S3I(s)->rrec.data, - data * S3I(s)->rrec.off, - offset into 'data' for next read * S3I(s)->rrec.length, - number of bytes. */ rr = &(S3I(s)->rrec); /* We are not handshaking and have no data yet, * so process data buffered during the last handshake * in advance, if any. */ if (S3I(s)->hs.state == SSL_ST_OK && rr->length == 0) { pitem *item; item = pqueue_pop(D1I(s)->buffered_app_data.q); if (item) { dtls1_copy_record(s, item); 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->internal->rstate == SSL_ST_READ_BODY)) { ret = dtls1_get_record(s); if (ret <= 0) { ret = dtls1_read_failed(s, ret); /* anything other than a timeout is an error */ if (ret <= 0) return (ret); else goto start; } } if (D1I(s)->listen && rr->type != SSL3_RT_HANDSHAKE) { rr->length = 0; goto start; } /* we now have a packet which can be read and processed */ if (S3I(s)->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. */ if (dtls1_buffer_record(s, &(D1I(s)->buffered_app_data), rr->seq_num) < 0) { SSLerror(s, 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->internal->shutdown & SSL_RECEIVED_SHUTDOWN) { rr->length = 0; s->internal->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; SSLerror(s, 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->internal->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 D1I(s)->handshake_fragment; dest = D1I(s)->handshake_fragment; dest_len = &D1I(s)->handshake_fragment_len; } else if (rr->type == SSL3_RT_ALERT) { dest_maxlen = sizeof(D1I(s)->alert_fragment); dest = D1I(s)->alert_fragment; dest_len = &D1I(s)->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; S3I(s)->in_read_app_data = 2; bio = SSL_get_rbio(s); s->internal->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; SSLerror(s, 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->internal->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; } } /* D1I(s)->handshake_fragment_len == 12 iff rr->type == SSL3_RT_HANDSHAKE; * D1I(s)->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) && (D1I(s)->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) && (D1I(s)->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) && (s->session != NULL) && (s->session->cipher != NULL)) { D1I(s)->handshake_fragment_len = 0; if ((D1I(s)->handshake_fragment[1] != 0) || (D1I(s)->handshake_fragment[2] != 0) || (D1I(s)->handshake_fragment[3] != 0)) { al = SSL_AD_DECODE_ERROR; SSLerror(s, SSL_R_BAD_HELLO_REQUEST); goto f_err; } /* no need to check sequence number on HELLO REQUEST messages */ if (s->internal->msg_callback) s->internal->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, D1I(s)->handshake_fragment, 4, s, s->internal->msg_callback_arg); if (SSL_is_init_finished(s) && !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) && !S3I(s)->renegotiate) { D1I(s)->handshake_read_seq++; s->internal->new_session = 1; ssl3_renegotiate(s); if (ssl3_renegotiate_check(s)) { i = s->internal->handshake_func(s); if (i < 0) return (i); if (i == 0) { SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE); return (-1); } if (!(s->internal->mode & SSL_MODE_AUTO_RETRY)) { if (S3I(s)->rbuf.left == 0) /* no read-ahead left? */ { BIO *bio; /* In the case where we try to read application data, * but we trigger an SSL handshake, we return -1 with * the retry option set. Otherwise renegotiation may * cause nasty problems in the blocking world */ s->internal->rwstate = SSL_READING; bio = SSL_get_rbio(s); BIO_clear_retry_flags(bio); BIO_set_retry_read(bio); return (-1); } } } } /* we either finished a handshake or ignored the request, * now try again to obtain the (application) data we were asked for */ goto start; } if (D1I(s)->alert_fragment_len >= DTLS1_AL_HEADER_LENGTH) { int alert_level = D1I(s)->alert_fragment[0]; int alert_descr = D1I(s)->alert_fragment[1]; D1I(s)->alert_fragment_len = 0; if (s->internal->msg_callback) s->internal->msg_callback(0, s->version, SSL3_RT_ALERT, D1I(s)->alert_fragment, 2, s, s->internal->msg_callback_arg); if (s->internal->info_callback != NULL) cb = s->internal->info_callback; else if (s->ctx->internal->info_callback != NULL) cb = s->ctx->internal->info_callback; if (cb != NULL) { j = (alert_level << 8) | alert_descr; cb(s, SSL_CB_READ_ALERT, j); } if (alert_level == 1) /* warning */ { S3I(s)->warn_alert = alert_descr; if (alert_descr == SSL_AD_CLOSE_NOTIFY) { s->internal->shutdown |= SSL_RECEIVED_SHUTDOWN; return (0); } } else if (alert_level == 2) /* fatal */ { s->internal->rwstate = SSL_NOTHING; S3I(s)->fatal_alert = alert_descr; SSLerror(s, SSL_AD_REASON_OFFSET + alert_descr); ERR_asprintf_error_data("SSL alert number %d", alert_descr); s->internal->shutdown|=SSL_RECEIVED_SHUTDOWN; SSL_CTX_remove_session(s->ctx, s->session); return (0); } else { al = SSL_AD_ILLEGAL_PARAMETER; SSLerror(s, SSL_R_UNKNOWN_ALERT_TYPE); goto f_err; } goto start; } if (s->internal->shutdown & SSL_SENT_SHUTDOWN) /* but we have not received a shutdown */ { s->internal->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_DECODE_ERROR; SSLerror(s, SSL_R_BAD_CHANGE_CIPHER_SPEC); goto f_err; } rr->length = 0; if (s->internal->msg_callback) s->internal->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1, s, s->internal->msg_callback_arg); /* We can't process a CCS now, because previous handshake * messages are still missing, so just drop it. */ if (!D1I(s)->change_cipher_spec_ok) { goto start; } D1I(s)->change_cipher_spec_ok = 0; S3I(s)->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 ((D1I(s)->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) && !s->internal->in_handshake) { struct hm_header_st msg_hdr; /* this may just be a stale retransmit */ if (!dtls1_get_message_header(rr->data, &msg_hdr)) return -1; if (rr->epoch != D1I(s)->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 (((S3I(s)->hs.state&SSL_ST_MASK) == SSL_ST_OK) && !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS)) { S3I(s)->hs.state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT; s->internal->renegotiate = 1; s->internal->new_session = 1; } i = s->internal->handshake_func(s); if (i < 0) return (i); if (i == 0) { SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE); return (-1); } if (!(s->internal->mode & SSL_MODE_AUTO_RETRY)) { if (S3I(s)->rbuf.left == 0) /* no read-ahead left? */ { BIO *bio; /* In the case where we try to read application data, * but we trigger an SSL handshake, we return -1 with * the retry option set. Otherwise renegotiation may * cause nasty problems in the blocking world */ s->internal->rwstate = SSL_READING; bio = SSL_get_rbio(s); BIO_clear_retry_flags(bio); BIO_set_retry_read(bio); return (-1); } } goto start; } switch (rr->type) { default: /* TLS just ignores unknown message types */ if (s->version == TLS1_VERSION) { rr->length = 0; goto start; } al = SSL_AD_UNEXPECTED_MESSAGE; SSLerror(s, 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->internal->in_handshake is set, but that * should not happen when type != rr->type */ al = SSL_AD_UNEXPECTED_MESSAGE; SSLerror(s, 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 (S3I(s)->in_read_app_data && (S3I(s)->total_renegotiations != 0) && (((S3I(s)->hs.state & SSL_ST_CONNECT) && (S3I(s)->hs.state >= SSL3_ST_CW_CLNT_HELLO_A) && (S3I(s)->hs.state <= SSL3_ST_CR_SRVR_HELLO_A)) || ( (S3I(s)->hs.state & SSL_ST_ACCEPT) && (S3I(s)->hs.state <= SSL3_ST_SW_HELLO_REQ_A) && (S3I(s)->hs.state >= SSL3_ST_SR_CLNT_HELLO_A)))) { S3I(s)->in_read_app_data = 2; return (-1); } else { al = SSL_AD_UNEXPECTED_MESSAGE; SSLerror(s, 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->internal->in_handshake) { i = s->internal->handshake_func(s); if (i < 0) return (i); if (i == 0) { SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE); return -1; } } if (len > SSL3_RT_MAX_PLAIN_LENGTH) { SSLerror(s, 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) && (D1I(s)->handshake_fragment_len > 0)) /* (partially) satisfy request from storage */ { unsigned char *src = D1I(s)->handshake_fragment; unsigned char *dst = buf; unsigned int k, n; /* peek == 0 */ n = 0; while ((len > 0) && (D1I(s)->handshake_fragment_len > 0)) { *dst++ = *src++; len--; D1I(s)->handshake_fragment_len--; n++; } /* move any remaining fragment bytes: */ for (k = 0; k < D1I(s)->handshake_fragment_len; k++) D1I(s)->handshake_fragment[k] = *src++; return n; } return 0; } /* Call this to write data in records of type 'type' * It will return <= 0 if not all data has been sent or non-blocking IO. */ int dtls1_write_bytes(SSL *s, int type, const void *buf, int len) { int i; OPENSSL_assert(len <= SSL3_RT_MAX_PLAIN_LENGTH); s->internal->rwstate = SSL_NOTHING; i = do_dtls1_write(s, type, buf, len); return i; } int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len) { unsigned char *p; int i, mac_size, clear = 0; SSL3_RECORD *wr; SSL3_BUFFER *wb; SSL_SESSION *sess; int bs; CBB cbb; memset(&cbb, 0, sizeof(cbb)); /* first check if there is a SSL3_BUFFER still being written * out. This will happen with non blocking IO */ if (S3I(s)->wbuf.left != 0) { OPENSSL_assert(0); /* XDTLS: want to see if we ever get here */ return (ssl3_write_pending(s, type, buf, len)); } /* If we have an alert to send, lets send it */ if (S3I(s)->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 = &(S3I(s)->wrec); wb = &(S3I(s)->wbuf); sess = s->session; if ((sess == NULL) || (s->internal->enc_write_ctx == NULL) || (EVP_MD_CTX_md(s->internal->write_hash) == NULL)) clear = 1; if (clear) mac_size = 0; else { mac_size = EVP_MD_CTX_size(s->internal->write_hash); if (mac_size < 0) goto err; } /* DTLS implements explicit IV, so no need for empty fragments. */ p = wb->buf; if (!CBB_init_fixed(&cbb, p, DTLS1_RT_HEADER_LENGTH)) goto err; /* Write the header. */ if (!CBB_add_u8(&cbb, type)) goto err; if (!CBB_add_u16(&cbb, s->version)) goto err; if (!CBB_add_u16(&cbb, D1I(s)->w_epoch)) goto err; if (!CBB_add_bytes(&cbb, &(S3I(s)->write_sequence[2]), 6)) goto err; p += DTLS1_RT_HEADER_LENGTH; /* lets setup the record stuff. */ /* Make space for the explicit IV in case of CBC. * (this is a bit of a boundary violation, but what the heck). */ if (s->internal->enc_write_ctx && (EVP_CIPHER_mode(s->internal->enc_write_ctx->cipher) & EVP_CIPH_CBC_MODE)) bs = EVP_CIPHER_block_size(s->internal->enc_write_ctx->cipher); else bs = 0; wr->type = type; wr->data = p + bs; /* 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 (tls1_mac(s, &(p[wr->length + bs]), 1) < 0) goto err; wr->length += mac_size; } /* this is true regardless of mac size */ wr->input = p; wr->data = p; /* bs != 0 in case of CBC */ if (bs) { arc4random_buf(p, bs); /* master IV and last CBC residue stand for * the rest of randomness */ wr->length += bs; } /* dtls1_enc can only have an error on read */ dtls1_enc(s, 1); if (!CBB_add_u16(&cbb, wr->length)) goto err; if (!CBB_finish(&cbb, NULL, NULL)) goto err; /* 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; tls1_record_sequence_increment(S3I(s)->write_sequence); /* now let's set up wb */ wb->left = wr->length; wb->offset = 0; /* memorize arguments so that ssl3_write_pending can detect bad write retries later */ S3I(s)->wpend_tot = len; S3I(s)->wpend_buf = buf; S3I(s)->wpend_type = type; S3I(s)->wpend_ret = len; /* we now just need to write the buffer */ return ssl3_write_pending(s, type, buf, len); err: CBB_cleanup(&cbb); return -1; } static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap) { int cmp; unsigned int shift; const unsigned char *seq = S3I(s)->read_sequence; cmp = satsub64be(seq, bitmap->max_seq_num); if (cmp > 0) { memcpy (S3I(s)->rrec.seq_num, seq, 8); return 1; /* this record in new */ } shift = -cmp; if (shift >= sizeof(bitmap->map)*8) return 0; /* stale, outside the window */ else if (bitmap->map & (1UL << shift)) return 0; /* record previously received */ memcpy(S3I(s)->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 = S3I(s)->read_sequence; cmp = satsub64be(seq, bitmap->max_seq_num); if (cmp > 0) { shift = cmp; if (shift < sizeof(bitmap->map)*8) bitmap->map <<= shift, bitmap->map |= 1UL; else bitmap->map = 1UL; memcpy(bitmap->max_seq_num, seq, 8); } else { shift = -cmp; if (shift < sizeof(bitmap->map) * 8) bitmap->map |= 1UL << shift; } } int dtls1_dispatch_alert(SSL *s) { int i, j; void (*cb)(const SSL *ssl, int type, int val) = NULL; unsigned char buf[DTLS1_AL_HEADER_LENGTH]; unsigned char *ptr = &buf[0]; S3I(s)->alert_dispatch = 0; memset(buf, 0x00, sizeof(buf)); *ptr++ = S3I(s)->send_alert[0]; *ptr++ = S3I(s)->send_alert[1]; i = do_dtls1_write(s, SSL3_RT_ALERT, &buf[0], sizeof(buf)); if (i <= 0) { S3I(s)->alert_dispatch = 1; /* fprintf( stderr, "not done with alert\n" ); */ } else { if (S3I(s)->send_alert[0] == SSL3_AL_FATAL) (void)BIO_flush(s->wbio); if (s->internal->msg_callback) s->internal->msg_callback(1, s->version, SSL3_RT_ALERT, S3I(s)->send_alert, 2, s, s->internal->msg_callback_arg); if (s->internal->info_callback != NULL) cb = s->internal->info_callback; else if (s->ctx->internal->info_callback != NULL) cb = s->ctx->internal->info_callback; if (cb != NULL) { j = (S3I(s)->send_alert[0]<<8)|S3I(s)->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 == D1I(s)->r_epoch) return &D1I(s)->bitmap; /* Only HM and ALERT messages can be from the next epoch */ else if (rr->epoch == (unsigned long)(D1I(s)->r_epoch + 1) && (rr->type == SSL3_RT_HANDSHAKE || rr->type == SSL3_RT_ALERT)) { *is_next_epoch = 1; return &D1I(s)->next_bitmap; } return NULL; } void dtls1_reset_seq_numbers(SSL *s, int rw) { unsigned char *seq; unsigned int seq_bytes = sizeof(S3I(s)->read_sequence); if (rw & SSL3_CC_READ) { seq = S3I(s)->read_sequence; D1I(s)->r_epoch++; memcpy(&(D1I(s)->bitmap), &(D1I(s)->next_bitmap), sizeof(DTLS1_BITMAP)); memset(&(D1I(s)->next_bitmap), 0x00, sizeof(DTLS1_BITMAP)); } else { seq = S3I(s)->write_sequence; memcpy(D1I(s)->last_write_sequence, seq, sizeof(S3I(s)->write_sequence)); D1I(s)->w_epoch++; } memset(seq, 0x00, seq_bytes); }