/* * Copyright 2005-2023 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the Apache License 2.0 (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy * in the file LICENSE in the source distribution or at * https://www.openssl.org/source/license.html */ #include #include #include #include #include "../ssl_local.h" #include "statem_local.h" #include "internal/cryptlib.h" #include #include #include #include #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8) #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \ if ((end) - (start) <= 8) { \ long ii; \ for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \ } else { \ long ii; \ bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \ for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \ bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \ } } #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \ long ii; \ is_complete = 1; \ if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \ if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \ if (bitmask[ii] != 0xff) { is_complete = 0; break; } } static unsigned char bitmask_start_values[] = { 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80 }; static unsigned char bitmask_end_values[] = { 0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f }; static void dtls1_fix_message_header(SSL_CONNECTION *s, size_t frag_off, size_t frag_len); static unsigned char *dtls1_write_message_header(SSL_CONNECTION *s, unsigned char *p); static void dtls1_set_message_header_int(SSL_CONNECTION *s, unsigned char mt, size_t len, unsigned short seq_num, size_t frag_off, size_t frag_len); static int dtls_get_reassembled_message(SSL_CONNECTION *s, int *errtype, size_t *len); static hm_fragment *dtls1_hm_fragment_new(size_t frag_len, int reassembly) { hm_fragment *frag = NULL; unsigned char *buf = NULL; unsigned char *bitmask = NULL; if ((frag = OPENSSL_zalloc(sizeof(*frag))) == NULL) return NULL; if (frag_len) { if ((buf = OPENSSL_malloc(frag_len)) == NULL) { OPENSSL_free(frag); return NULL; } } /* zero length fragment gets zero frag->fragment */ frag->fragment = buf; /* Initialize reassembly bitmask if necessary */ if (reassembly) { bitmask = OPENSSL_zalloc(RSMBLY_BITMASK_SIZE(frag_len)); if (bitmask == NULL) { OPENSSL_free(buf); OPENSSL_free(frag); return NULL; } } frag->reassembly = bitmask; return frag; } void dtls1_hm_fragment_free(hm_fragment *frag) { if (!frag) return; OPENSSL_free(frag->fragment); OPENSSL_free(frag->reassembly); OPENSSL_free(frag); } /* * send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or * SSL3_RT_CHANGE_CIPHER_SPEC) */ int dtls1_do_write(SSL_CONNECTION *s, uint8_t type) { int ret; size_t written; size_t curr_mtu; int retry = 1; size_t len, frag_off, overhead, used_len; SSL *ssl = SSL_CONNECTION_GET_SSL(s); if (!dtls1_query_mtu(s)) return -1; if (s->d1->mtu < dtls1_min_mtu(s)) /* should have something reasonable now */ return -1; if (s->init_off == 0 && type == SSL3_RT_HANDSHAKE) { if (!ossl_assert(s->init_num == s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH)) return -1; } overhead = s->rlayer.wrlmethod->get_max_record_overhead(s->rlayer.wrl); frag_off = 0; s->rwstate = SSL_NOTHING; /* s->init_num shouldn't ever be < 0...but just in case */ while (s->init_num > 0) { if (type == SSL3_RT_HANDSHAKE && s->init_off != 0) { /* We must be writing a fragment other than the first one */ if (frag_off > 0) { /* This is the first attempt at writing out this fragment */ if (s->init_off <= DTLS1_HM_HEADER_LENGTH) { /* * Each fragment that was already sent must at least have * contained the message header plus one other byte. * Therefore |init_off| must have progressed by at least * |DTLS1_HM_HEADER_LENGTH + 1| bytes. If not something went * wrong. */ return -1; } /* * Adjust |init_off| and |init_num| to allow room for a new * message header for this fragment. */ s->init_off -= DTLS1_HM_HEADER_LENGTH; s->init_num += DTLS1_HM_HEADER_LENGTH; } else { /* * We must have been called again after a retry so use the * fragment offset from our last attempt. We do not need * to adjust |init_off| and |init_num| as above, because * that should already have been done before the retry. */ frag_off = s->d1->w_msg_hdr.frag_off; } } used_len = BIO_wpending(s->wbio) + overhead; if (s->d1->mtu > used_len) curr_mtu = s->d1->mtu - used_len; else curr_mtu = 0; if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) { /* * grr.. we could get an error if MTU picked was wrong */ ret = BIO_flush(s->wbio); if (ret <= 0) { s->rwstate = SSL_WRITING; return ret; } if (s->d1->mtu > overhead + DTLS1_HM_HEADER_LENGTH) { curr_mtu = s->d1->mtu - overhead; } else { /* Shouldn't happen */ return -1; } } /* * We just checked that s->init_num > 0 so this cast should be safe */ if (((unsigned int)s->init_num) > curr_mtu) len = curr_mtu; else len = s->init_num; if (len > ssl_get_max_send_fragment(s)) len = ssl_get_max_send_fragment(s); /* * XDTLS: this function is too long. split out the CCS part */ if (type == SSL3_RT_HANDSHAKE) { if (len < DTLS1_HM_HEADER_LENGTH) { /* * len is so small that we really can't do anything sensible * so fail */ return -1; } dtls1_fix_message_header(s, frag_off, len - DTLS1_HM_HEADER_LENGTH); dtls1_write_message_header(s, (unsigned char *)&s->init_buf-> data[s->init_off]); } ret = dtls1_write_bytes(s, type, &s->init_buf->data[s->init_off], len, &written); if (ret <= 0) { /* * might need to update MTU here, but we don't know which * previous packet caused the failure -- so can't really * retransmit anything. continue as if everything is fine and * wait for an alert to handle the retransmit */ if (retry && BIO_ctrl(SSL_get_wbio(ssl), BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0) { if (!(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) { if (!dtls1_query_mtu(s)) return -1; /* Have one more go */ retry = 0; } else return -1; } else { return -1; } } else { /* * bad if this assert fails, only part of the handshake message * got sent. but why would this happen? */ if (!ossl_assert(len == written)) return -1; /* * We should not exceed the MTU size. If compression is in use * then the max record overhead calculation is unreliable so we do * not check in that case. We use assert rather than ossl_assert * because in a production build, if this assert were ever to fail, * then the best thing to do is probably carry on regardless. */ assert(s->s3.tmp.new_compression != NULL || BIO_wpending(s->wbio) <= (int)s->d1->mtu); if (type == SSL3_RT_HANDSHAKE && !s->d1->retransmitting) { /* * should not be done for 'Hello Request's, but in that case * we'll ignore the result anyway */ unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off]; const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; size_t xlen; if (frag_off == 0 && s->version != DTLS1_BAD_VER) { /* * reconstruct message header is if it is being sent in * single fragment */ *p++ = msg_hdr->type; l2n3(msg_hdr->msg_len, p); s2n(msg_hdr->seq, p); l2n3(0, p); l2n3(msg_hdr->msg_len, p); p -= DTLS1_HM_HEADER_LENGTH; xlen = written; } else { p += DTLS1_HM_HEADER_LENGTH; xlen = written - DTLS1_HM_HEADER_LENGTH; } if (!ssl3_finish_mac(s, p, xlen)) return -1; } if (written == s->init_num) { if (s->msg_callback) s->msg_callback(1, s->version, type, s->init_buf->data, (size_t)(s->init_off + s->init_num), ssl, s->msg_callback_arg); s->init_off = 0; /* done writing this message */ s->init_num = 0; return 1; } s->init_off += written; s->init_num -= written; written -= DTLS1_HM_HEADER_LENGTH; frag_off += written; /* * We save the fragment offset for the next fragment so we have it * available in case of an IO retry. We don't know the length of the * next fragment yet so just set that to 0 for now. It will be * updated again later. */ dtls1_fix_message_header(s, frag_off, 0); } } return 0; } int dtls_get_message(SSL_CONNECTION *s, int *mt) { struct hm_header_st *msg_hdr; unsigned char *p; size_t msg_len; size_t tmplen; int errtype; msg_hdr = &s->d1->r_msg_hdr; memset(msg_hdr, 0, sizeof(*msg_hdr)); again: if (!dtls_get_reassembled_message(s, &errtype, &tmplen)) { if (errtype == DTLS1_HM_BAD_FRAGMENT || errtype == DTLS1_HM_FRAGMENT_RETRY) { /* bad fragment received */ goto again; } return 0; } *mt = s->s3.tmp.message_type; p = (unsigned char *)s->init_buf->data; if (*mt == SSL3_MT_CHANGE_CIPHER_SPEC) { if (s->msg_callback) { s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, p, 1, SSL_CONNECTION_GET_SSL(s), s->msg_callback_arg); } /* * This isn't a real handshake message so skip the processing below. */ return 1; } msg_len = msg_hdr->msg_len; /* reconstruct message header */ *(p++) = msg_hdr->type; l2n3(msg_len, p); s2n(msg_hdr->seq, p); l2n3(0, p); l2n3(msg_len, p); memset(msg_hdr, 0, sizeof(*msg_hdr)); s->d1->handshake_read_seq++; s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH; return 1; } /* * Actually we already have the message body - but this is an opportunity for * DTLS to do any further processing it wants at the same point that TLS would * be asked for the message body. */ int dtls_get_message_body(SSL_CONNECTION *s, size_t *len) { unsigned char *msg = (unsigned char *)s->init_buf->data; size_t msg_len = s->init_num + DTLS1_HM_HEADER_LENGTH; if (s->s3.tmp.message_type == SSL3_MT_CHANGE_CIPHER_SPEC) { /* Nothing to be done */ goto end; } /* * If receiving Finished, record MAC of prior handshake messages for * Finished verification. */ if (*(s->init_buf->data) == SSL3_MT_FINISHED && !ssl3_take_mac(s)) { /* SSLfatal() already called */ return 0; } if (s->version == DTLS1_BAD_VER) { msg += DTLS1_HM_HEADER_LENGTH; msg_len -= DTLS1_HM_HEADER_LENGTH; } if (!ssl3_finish_mac(s, msg, msg_len)) return 0; if (s->msg_callback) s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data, s->init_num + DTLS1_HM_HEADER_LENGTH, SSL_CONNECTION_GET_SSL(s), s->msg_callback_arg); end: *len = s->init_num; return 1; } /* * dtls1_max_handshake_message_len returns the maximum number of bytes * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but * may be greater if the maximum certificate list size requires it. */ static size_t dtls1_max_handshake_message_len(const SSL_CONNECTION *s) { size_t max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH; if (max_len < s->max_cert_list) return s->max_cert_list; return max_len; } static int dtls1_preprocess_fragment(SSL_CONNECTION *s, struct hm_header_st *msg_hdr) { size_t frag_off, frag_len, msg_len; msg_len = msg_hdr->msg_len; frag_off = msg_hdr->frag_off; frag_len = msg_hdr->frag_len; /* sanity checking */ if ((frag_off + frag_len) > msg_len || msg_len > dtls1_max_handshake_message_len(s)) { SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_EXCESSIVE_MESSAGE_SIZE); return 0; } if (s->d1->r_msg_hdr.frag_off == 0) { /* first fragment */ /* * msg_len is limited to 2^24, but is effectively checked against * dtls_max_handshake_message_len(s) above */ if (!BUF_MEM_grow_clean(s->init_buf, msg_len + DTLS1_HM_HEADER_LENGTH)) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_BUF_LIB); return 0; } s->s3.tmp.message_size = msg_len; s->d1->r_msg_hdr.msg_len = msg_len; s->s3.tmp.message_type = msg_hdr->type; s->d1->r_msg_hdr.type = msg_hdr->type; s->d1->r_msg_hdr.seq = msg_hdr->seq; } else if (msg_len != s->d1->r_msg_hdr.msg_len) { /* * They must be playing with us! BTW, failure to enforce upper limit * would open possibility for buffer overrun. */ SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_EXCESSIVE_MESSAGE_SIZE); return 0; } return 1; } /* * Returns 1 if there is a buffered fragment available, 0 if not, or -1 on a * fatal error. */ static int dtls1_retrieve_buffered_fragment(SSL_CONNECTION *s, size_t *len) { /*- * (0) check whether the desired fragment is available * if so: * (1) copy over the fragment to s->init_buf->data[] * (2) update s->init_num */ pitem *item; piterator iter; hm_fragment *frag; int ret; int chretran = 0; iter = pqueue_iterator(s->d1->buffered_messages); do { item = pqueue_next(&iter); if (item == NULL) return 0; frag = (hm_fragment *)item->data; if (frag->msg_header.seq < s->d1->handshake_read_seq) { pitem *next; hm_fragment *nextfrag; if (!s->server || frag->msg_header.seq != 0 || s->d1->handshake_read_seq != 1 || s->statem.hand_state != DTLS_ST_SW_HELLO_VERIFY_REQUEST) { /* * This is a stale message that has been buffered so clear it. * It is safe to pop this message from the queue even though * we have an active iterator */ pqueue_pop(s->d1->buffered_messages); dtls1_hm_fragment_free(frag); pitem_free(item); item = NULL; frag = NULL; } else { /* * We have fragments for a ClientHello without a cookie, * even though we have sent a HelloVerifyRequest. It is possible * that the HelloVerifyRequest got lost and this is a * retransmission of the original ClientHello */ next = pqueue_next(&iter); if (next != NULL) { nextfrag = (hm_fragment *)next->data; if (nextfrag->msg_header.seq == s->d1->handshake_read_seq) { /* * We have fragments for both a ClientHello without * cookie and one with. Ditch the one without. */ pqueue_pop(s->d1->buffered_messages); dtls1_hm_fragment_free(frag); pitem_free(item); item = next; frag = nextfrag; } else { chretran = 1; } } else { chretran = 1; } } } } while (item == NULL); /* Don't return if reassembly still in progress */ if (frag->reassembly != NULL) return 0; if (s->d1->handshake_read_seq == frag->msg_header.seq || chretran) { size_t frag_len = frag->msg_header.frag_len; pqueue_pop(s->d1->buffered_messages); /* Calls SSLfatal() as required */ ret = dtls1_preprocess_fragment(s, &frag->msg_header); if (ret && frag->msg_header.frag_len > 0) { unsigned char *p = (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH; memcpy(&p[frag->msg_header.frag_off], frag->fragment, frag->msg_header.frag_len); } dtls1_hm_fragment_free(frag); pitem_free(item); if (ret) { if (chretran) { /* * We got a new ClientHello with a message sequence of 0. * Reset the read/write sequences back to the beginning. * We process it like this is the first time we've seen a * ClientHello from the client. */ s->d1->handshake_read_seq = 0; s->d1->next_handshake_write_seq = 0; } *len = frag_len; return 1; } /* Fatal error */ s->init_num = 0; return -1; } else { return 0; } } static int dtls1_reassemble_fragment(SSL_CONNECTION *s, const struct hm_header_st *msg_hdr) { hm_fragment *frag = NULL; pitem *item = NULL; int i = -1, is_complete; unsigned char seq64be[8]; size_t frag_len = msg_hdr->frag_len; size_t readbytes; SSL *ssl = SSL_CONNECTION_GET_SSL(s); if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len || msg_hdr->msg_len > dtls1_max_handshake_message_len(s)) goto err; if (frag_len == 0) { return DTLS1_HM_FRAGMENT_RETRY; } /* Try to find item in queue */ memset(seq64be, 0, sizeof(seq64be)); seq64be[6] = (unsigned char)(msg_hdr->seq >> 8); seq64be[7] = (unsigned char)msg_hdr->seq; item = pqueue_find(s->d1->buffered_messages, seq64be); if (item == NULL) { frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1); if (frag == NULL) goto err; memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr)); frag->msg_header.frag_len = frag->msg_header.msg_len; frag->msg_header.frag_off = 0; } else { frag = (hm_fragment *)item->data; if (frag->msg_header.msg_len != msg_hdr->msg_len) { item = NULL; frag = NULL; goto err; } } /* * If message is already reassembled, this must be a retransmit and can * be dropped. In this case item != NULL and so frag does not need to be * freed. */ if (frag->reassembly == NULL) { unsigned char devnull[256]; while (frag_len) { i = ssl->method->ssl_read_bytes(ssl, SSL3_RT_HANDSHAKE, NULL, devnull, frag_len > sizeof(devnull) ? sizeof(devnull) : frag_len, 0, &readbytes); if (i <= 0) goto err; frag_len -= readbytes; } return DTLS1_HM_FRAGMENT_RETRY; } /* read the body of the fragment (header has already been read */ i = ssl->method->ssl_read_bytes(ssl, SSL3_RT_HANDSHAKE, NULL, frag->fragment + msg_hdr->frag_off, frag_len, 0, &readbytes); if (i <= 0 || readbytes != frag_len) i = -1; if (i <= 0) goto err; RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off, (long)(msg_hdr->frag_off + frag_len)); if (!ossl_assert(msg_hdr->msg_len > 0)) goto err; RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len, is_complete); if (is_complete) { OPENSSL_free(frag->reassembly); frag->reassembly = NULL; } if (item == NULL) { item = pitem_new(seq64be, frag); if (item == NULL) { i = -1; goto err; } item = pqueue_insert(s->d1->buffered_messages, item); /* * pqueue_insert fails iff a duplicate item is inserted. However, * |item| cannot be a duplicate. If it were, |pqueue_find|, above, * would have returned it and control would never have reached this * branch. */ if (!ossl_assert(item != NULL)) goto err; } return DTLS1_HM_FRAGMENT_RETRY; err: if (item == NULL) dtls1_hm_fragment_free(frag); return -1; } static int dtls1_process_out_of_seq_message(SSL_CONNECTION *s, const struct hm_header_st *msg_hdr) { int i = -1; hm_fragment *frag = NULL; pitem *item = NULL; unsigned char seq64be[8]; size_t frag_len = msg_hdr->frag_len; size_t readbytes; SSL *ssl = SSL_CONNECTION_GET_SSL(s); if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len) goto err; /* Try to find item in queue, to prevent duplicate entries */ memset(seq64be, 0, sizeof(seq64be)); seq64be[6] = (unsigned char)(msg_hdr->seq >> 8); seq64be[7] = (unsigned char)msg_hdr->seq; item = pqueue_find(s->d1->buffered_messages, seq64be); /* * If we already have an entry and this one is a fragment, don't discard * it and rather try to reassemble it. */ if (item != NULL && frag_len != msg_hdr->msg_len) item = NULL; /* * Discard the message if sequence number was already there, is too far * in the future, already in the queue or if we received a FINISHED * before the SERVER_HELLO, which then must be a stale retransmit. */ if (msg_hdr->seq <= s->d1->handshake_read_seq || msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL || (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED)) { unsigned char devnull[256]; while (frag_len) { i = ssl->method->ssl_read_bytes(ssl, SSL3_RT_HANDSHAKE, NULL, devnull, frag_len > sizeof(devnull) ? sizeof(devnull) : frag_len, 0, &readbytes); if (i <= 0) goto err; frag_len -= readbytes; } } else { if (frag_len != msg_hdr->msg_len) { return dtls1_reassemble_fragment(s, msg_hdr); } if (frag_len > dtls1_max_handshake_message_len(s)) goto err; frag = dtls1_hm_fragment_new(frag_len, 0); if (frag == NULL) goto err; memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr)); if (frag_len) { /* * read the body of the fragment (header has already been read */ i = ssl->method->ssl_read_bytes(ssl, SSL3_RT_HANDSHAKE, NULL, frag->fragment, frag_len, 0, &readbytes); if (i<=0 || readbytes != frag_len) i = -1; if (i <= 0) goto err; } item = pitem_new(seq64be, frag); if (item == NULL) goto err; item = pqueue_insert(s->d1->buffered_messages, item); /* * pqueue_insert fails iff a duplicate item is inserted. However, * |item| cannot be a duplicate. If it were, |pqueue_find|, above, * would have returned it. Then, either |frag_len| != * |msg_hdr->msg_len| in which case |item| is set to NULL and it will * have been processed with |dtls1_reassemble_fragment|, above, or * the record will have been discarded. */ if (!ossl_assert(item != NULL)) goto err; } return DTLS1_HM_FRAGMENT_RETRY; err: if (item == NULL) dtls1_hm_fragment_free(frag); return 0; } static int dtls_get_reassembled_message(SSL_CONNECTION *s, int *errtype, size_t *len) { unsigned char wire[DTLS1_HM_HEADER_LENGTH]; size_t mlen, frag_off, frag_len; int i, ret; uint8_t recvd_type; struct hm_header_st msg_hdr; size_t readbytes; SSL *ssl = SSL_CONNECTION_GET_SSL(s); int chretran = 0; *errtype = 0; redo: /* see if we have the required fragment already */ ret = dtls1_retrieve_buffered_fragment(s, &frag_len); if (ret < 0) { /* SSLfatal() already called */ return 0; } if (ret > 0) { s->init_num = frag_len; *len = frag_len; return 1; } /* read handshake message header */ i = ssl->method->ssl_read_bytes(ssl, SSL3_RT_HANDSHAKE, &recvd_type, wire, DTLS1_HM_HEADER_LENGTH, 0, &readbytes); if (i <= 0) { /* nbio, or an error */ s->rwstate = SSL_READING; *len = 0; return 0; } if (recvd_type == SSL3_RT_CHANGE_CIPHER_SPEC) { if (wire[0] != SSL3_MT_CCS) { SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_BAD_CHANGE_CIPHER_SPEC); goto f_err; } memcpy(s->init_buf->data, wire, readbytes); s->init_num = readbytes - 1; s->init_msg = s->init_buf->data + 1; s->s3.tmp.message_type = SSL3_MT_CHANGE_CIPHER_SPEC; s->s3.tmp.message_size = readbytes - 1; *len = readbytes - 1; return 1; } /* Handshake fails if message header is incomplete */ if (readbytes != DTLS1_HM_HEADER_LENGTH) { SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_MESSAGE); goto f_err; } /* parse the message fragment header */ dtls1_get_message_header(wire, &msg_hdr); mlen = msg_hdr.msg_len; frag_off = msg_hdr.frag_off; frag_len = msg_hdr.frag_len; /* * We must have at least frag_len bytes left in the record to be read. * Fragments must not span records. */ if (frag_len > s->rlayer.tlsrecs[s->rlayer.curr_rec].length) { SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_LENGTH); goto f_err; } /* * if this is a future (or stale) message it gets buffered * (or dropped)--no further processing at this time * While listening, we accept seq 1 (ClientHello with cookie) * although we're still expecting seq 0 (ClientHello) */ if (msg_hdr.seq != s->d1->handshake_read_seq) { if (!s->server || msg_hdr.seq != 0 || s->d1->handshake_read_seq != 1 || wire[0] != SSL3_MT_CLIENT_HELLO || s->statem.hand_state != DTLS_ST_SW_HELLO_VERIFY_REQUEST) { *errtype = dtls1_process_out_of_seq_message(s, &msg_hdr); return 0; } /* * We received a ClientHello and sent back a HelloVerifyRequest. We * now seem to have received a retransmitted initial ClientHello. That * is allowed (possibly our HelloVerifyRequest got lost). */ chretran = 1; } if (frag_len && frag_len < mlen) { *errtype = dtls1_reassemble_fragment(s, &msg_hdr); return 0; } if (!s->server && s->d1->r_msg_hdr.frag_off == 0 && s->statem.hand_state != TLS_ST_OK && wire[0] == SSL3_MT_HELLO_REQUEST) { /* * The server may always send 'Hello Request' messages -- we are * doing a handshake anyway now, so ignore them if their format is * correct. Does not count for 'Finished' MAC. */ if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) { if (s->msg_callback) s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, wire, DTLS1_HM_HEADER_LENGTH, ssl, s->msg_callback_arg); s->init_num = 0; goto redo; } else { /* Incorrectly formatted Hello request */ SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_MESSAGE); goto f_err; } } if (!dtls1_preprocess_fragment(s, &msg_hdr)) { /* SSLfatal() already called */ goto f_err; } if (frag_len > 0) { unsigned char *p = (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH; i = ssl->method->ssl_read_bytes(ssl, SSL3_RT_HANDSHAKE, NULL, &p[frag_off], frag_len, 0, &readbytes); /* * This shouldn't ever fail due to NBIO because we already checked * that we have enough data in the record */ if (i <= 0) { s->rwstate = SSL_READING; *len = 0; return 0; } } else { readbytes = 0; } /* * XDTLS: an incorrectly formatted fragment should cause the handshake * to fail */ if (readbytes != frag_len) { SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_R_BAD_LENGTH); goto f_err; } if (chretran) { /* * We got a new ClientHello with a message sequence of 0. * Reset the read/write sequences back to the beginning. * We process it like this is the first time we've seen a ClientHello * from the client. */ s->d1->handshake_read_seq = 0; s->d1->next_handshake_write_seq = 0; } /* * Note that s->init_num is *not* used as current offset in * s->init_buf->data, but as a counter summing up fragments' lengths: as * soon as they sum up to handshake packet length, we assume we have got * all the fragments. */ *len = s->init_num = frag_len; return 1; f_err: s->init_num = 0; *len = 0; return 0; } /*- * for these 2 messages, we need to * ssl->session->read_sym_enc assign * ssl->session->read_compression assign * ssl->session->read_hash assign */ CON_FUNC_RETURN dtls_construct_change_cipher_spec(SSL_CONNECTION *s, WPACKET *pkt) { if (s->version == DTLS1_BAD_VER) { s->d1->next_handshake_write_seq++; if (!WPACKET_put_bytes_u16(pkt, s->d1->handshake_write_seq)) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); return CON_FUNC_ERROR; } } return CON_FUNC_SUCCESS; } #ifndef OPENSSL_NO_SCTP /* * Wait for a dry event. Should only be called at a point in the handshake * where we are not expecting any data from the peer except an alert. */ WORK_STATE dtls_wait_for_dry(SSL_CONNECTION *s) { int ret, errtype; size_t len; SSL *ssl = SSL_CONNECTION_GET_SSL(s); /* read app data until dry event */ ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(ssl)); if (ret < 0) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); return WORK_ERROR; } if (ret == 0) { /* * We're not expecting any more messages from the peer at this point - * but we could get an alert. If an alert is waiting then we will never * return successfully. Therefore we attempt to read a message. This * should never succeed but will process any waiting alerts. */ if (dtls_get_reassembled_message(s, &errtype, &len)) { /* The call succeeded! This should never happen */ SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_R_UNEXPECTED_MESSAGE); return WORK_ERROR; } s->s3.in_read_app_data = 2; s->rwstate = SSL_READING; BIO_clear_retry_flags(SSL_get_rbio(ssl)); BIO_set_retry_read(SSL_get_rbio(ssl)); return WORK_MORE_A; } return WORK_FINISHED_CONTINUE; } #endif int dtls1_read_failed(SSL_CONNECTION *s, int code) { SSL *ssl = SSL_CONNECTION_GET_SSL(s); if (code > 0) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); return 0; } if (!dtls1_is_timer_expired(s) || ossl_statem_in_error(s)) { /* * not a timeout, none of our business, let higher layers handle * this. in fact it's probably an error */ return code; } /* done, no need to send a retransmit */ if (!SSL_in_init(ssl)) { BIO_set_flags(SSL_get_rbio(ssl), BIO_FLAGS_READ); return code; } return dtls1_handle_timeout(s); } int dtls1_get_queue_priority(unsigned short seq, int is_ccs) { /* * The index of the retransmission queue actually is the message sequence * number, since the queue only contains messages of a single handshake. * However, the ChangeCipherSpec has no message sequence number and so * using only the sequence will result in the CCS and Finished having the * same index. To prevent this, the sequence number is multiplied by 2. * In case of a CCS 1 is subtracted. This does not only differ CSS and * Finished, it also maintains the order of the index (important for * priority queues) and fits in the unsigned short variable. */ return seq * 2 - is_ccs; } int dtls1_retransmit_buffered_messages(SSL_CONNECTION *s) { pqueue *sent = s->d1->sent_messages; piterator iter; pitem *item; hm_fragment *frag; int found = 0; iter = pqueue_iterator(sent); for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) { frag = (hm_fragment *)item->data; if (dtls1_retransmit_message(s, (unsigned short) dtls1_get_queue_priority (frag->msg_header.seq, frag->msg_header.is_ccs), &found) <= 0) return -1; } return 1; } int dtls1_buffer_message(SSL_CONNECTION *s, int is_ccs) { pitem *item; hm_fragment *frag; unsigned char seq64be[8]; /* * this function is called immediately after a message has been * serialized */ if (!ossl_assert(s->init_off == 0)) return 0; frag = dtls1_hm_fragment_new(s->init_num, 0); if (frag == NULL) return 0; memcpy(frag->fragment, s->init_buf->data, s->init_num); if (is_ccs) { /* For DTLS1_BAD_VER the header length is non-standard */ if (!ossl_assert(s->d1->w_msg_hdr.msg_len + ((s->version == DTLS1_BAD_VER) ? 3 : DTLS1_CCS_HEADER_LENGTH) == (unsigned int)s->init_num)) { dtls1_hm_fragment_free(frag); return 0; } } else { if (!ossl_assert(s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num)) { dtls1_hm_fragment_free(frag); return 0; } } frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len; frag->msg_header.seq = s->d1->w_msg_hdr.seq; frag->msg_header.type = s->d1->w_msg_hdr.type; frag->msg_header.frag_off = 0; frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len; frag->msg_header.is_ccs = is_ccs; /* save current state */ frag->msg_header.saved_retransmit_state.wrlmethod = s->rlayer.wrlmethod; frag->msg_header.saved_retransmit_state.wrl = s->rlayer.wrl; memset(seq64be, 0, sizeof(seq64be)); seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs) >> 8); seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs)); item = pitem_new(seq64be, frag); if (item == NULL) { dtls1_hm_fragment_free(frag); return 0; } pqueue_insert(s->d1->sent_messages, item); return 1; } int dtls1_retransmit_message(SSL_CONNECTION *s, unsigned short seq, int *found) { int ret; /* XDTLS: for now assuming that read/writes are blocking */ pitem *item; hm_fragment *frag; unsigned long header_length; unsigned char seq64be[8]; struct dtls1_retransmit_state saved_state; /* XDTLS: the requested message ought to be found, otherwise error */ memset(seq64be, 0, sizeof(seq64be)); seq64be[6] = (unsigned char)(seq >> 8); seq64be[7] = (unsigned char)seq; item = pqueue_find(s->d1->sent_messages, seq64be); if (item == NULL) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); *found = 0; return 0; } *found = 1; frag = (hm_fragment *)item->data; if (frag->msg_header.is_ccs) header_length = DTLS1_CCS_HEADER_LENGTH; else header_length = DTLS1_HM_HEADER_LENGTH; memcpy(s->init_buf->data, frag->fragment, frag->msg_header.msg_len + header_length); s->init_num = frag->msg_header.msg_len + header_length; dtls1_set_message_header_int(s, frag->msg_header.type, frag->msg_header.msg_len, frag->msg_header.seq, 0, frag->msg_header.frag_len); /* save current state */ saved_state.wrlmethod = s->rlayer.wrlmethod; saved_state.wrl = s->rlayer.wrl; s->d1->retransmitting = 1; /* restore state in which the message was originally sent */ s->rlayer.wrlmethod = frag->msg_header.saved_retransmit_state.wrlmethod; s->rlayer.wrl = frag->msg_header.saved_retransmit_state.wrl; /* * The old wrl may be still pointing at an old BIO. Update it to what we're * using now. */ s->rlayer.wrlmethod->set1_bio(s->rlayer.wrl, s->wbio); ret = dtls1_do_write(s, frag->msg_header.is_ccs ? SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE); /* restore current state */ s->rlayer.wrlmethod = saved_state.wrlmethod; s->rlayer.wrl = saved_state.wrl; s->d1->retransmitting = 0; (void)BIO_flush(s->wbio); return ret; } void dtls1_set_message_header(SSL_CONNECTION *s, unsigned char mt, size_t len, size_t frag_off, size_t frag_len) { if (frag_off == 0) { s->d1->handshake_write_seq = s->d1->next_handshake_write_seq; s->d1->next_handshake_write_seq++; } dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq, frag_off, frag_len); } /* don't actually do the writing, wait till the MTU has been retrieved */ static void dtls1_set_message_header_int(SSL_CONNECTION *s, unsigned char mt, size_t len, unsigned short seq_num, size_t frag_off, size_t frag_len) { struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; msg_hdr->type = mt; msg_hdr->msg_len = len; msg_hdr->seq = seq_num; msg_hdr->frag_off = frag_off; msg_hdr->frag_len = frag_len; } static void dtls1_fix_message_header(SSL_CONNECTION *s, size_t frag_off, size_t frag_len) { struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; msg_hdr->frag_off = frag_off; msg_hdr->frag_len = frag_len; } static unsigned char *dtls1_write_message_header(SSL_CONNECTION *s, unsigned char *p) { struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; *p++ = msg_hdr->type; l2n3(msg_hdr->msg_len, p); s2n(msg_hdr->seq, p); l2n3(msg_hdr->frag_off, p); l2n3(msg_hdr->frag_len, p); return p; } void dtls1_get_message_header(const unsigned char *data, struct hm_header_st *msg_hdr) { memset(msg_hdr, 0, sizeof(*msg_hdr)); msg_hdr->type = *(data++); n2l3(data, msg_hdr->msg_len); n2s(data, msg_hdr->seq); n2l3(data, msg_hdr->frag_off); n2l3(data, msg_hdr->frag_len); } int dtls1_set_handshake_header(SSL_CONNECTION *s, WPACKET *pkt, int htype) { unsigned char *header; if (htype == SSL3_MT_CHANGE_CIPHER_SPEC) { s->d1->handshake_write_seq = s->d1->next_handshake_write_seq; dtls1_set_message_header_int(s, SSL3_MT_CCS, 0, s->d1->handshake_write_seq, 0, 0); if (!WPACKET_put_bytes_u8(pkt, SSL3_MT_CCS)) return 0; } else { dtls1_set_message_header(s, htype, 0, 0, 0); /* * We allocate space at the start for the message header. This gets * filled in later */ if (!WPACKET_allocate_bytes(pkt, DTLS1_HM_HEADER_LENGTH, &header) || !WPACKET_start_sub_packet(pkt)) return 0; } return 1; } int dtls1_close_construct_packet(SSL_CONNECTION *s, WPACKET *pkt, int htype) { size_t msglen; if ((htype != SSL3_MT_CHANGE_CIPHER_SPEC && !WPACKET_close(pkt)) || !WPACKET_get_length(pkt, &msglen) || msglen > INT_MAX) return 0; if (htype != SSL3_MT_CHANGE_CIPHER_SPEC) { s->d1->w_msg_hdr.msg_len = msglen - DTLS1_HM_HEADER_LENGTH; s->d1->w_msg_hdr.frag_len = msglen - DTLS1_HM_HEADER_LENGTH; } s->init_num = (int)msglen; s->init_off = 0; if (htype != DTLS1_MT_HELLO_VERIFY_REQUEST) { /* Buffer the message to handle re-xmits */ if (!dtls1_buffer_message(s, htype == SSL3_MT_CHANGE_CIPHER_SPEC ? 1 : 0)) return 0; } return 1; }