diff options
Diffstat (limited to 'crypto/openssl/ssl/statem/statem_dtls.c')
| -rw-r--r-- | crypto/openssl/ssl/statem/statem_dtls.c | 1374 |
1 files changed, 1374 insertions, 0 deletions
diff --git a/crypto/openssl/ssl/statem/statem_dtls.c b/crypto/openssl/ssl/statem/statem_dtls.c new file mode 100644 index 000000000000..78baeed90319 --- /dev/null +++ b/crypto/openssl/ssl/statem/statem_dtls.c @@ -0,0 +1,1374 @@ +/* + * Copyright 2005-2025 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 <assert.h> +#include <limits.h> +#include <string.h> +#include <stdio.h> +#include "../ssl_local.h" +#include "statem_local.h" +#include "internal/cryptlib.h" +#include "internal/ssl_unwrap.h" +#include <openssl/buffer.h> + +#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 const unsigned char bitmask_start_values[] = { + 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80 +}; +static const 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); + SSL *ussl = SSL_CONNECTION_GET_USER_SSL(s); + uint8_t saved_payload[DTLS1_HM_HEADER_LENGTH]; + + 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); + + /* + * Save the data that will be overwritten by + * dtls1_write_messsage_header so no corruption occurs when using + * a msg callback. + */ + if (s->msg_callback && s->init_off != 0) + memcpy(saved_payload, &s->init_buf->data[s->init_off], + sizeof(saved_payload)); + + 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 (type == SSL3_RT_HANDSHAKE && s->msg_callback && s->init_off != 0) + memcpy(&s->init_buf->data[s->init_off], saved_payload, + sizeof(saved_payload)); + + 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, + s->init_off + s->init_num, ussl, + 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_USER_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_USER_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) +{ + 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); + SSL *ussl = SSL_CONNECTION_GET_USER_SSL(s); + int chretran = 0; + unsigned char *p; + + *errtype = 0; + + p = (unsigned char *)s->init_buf->data; + + 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, p, + 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 (p[0] != SSL3_MT_CCS) { + SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, + SSL_R_BAD_CHANGE_CIPHER_SPEC); + goto f_err; + } + + 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(p, &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 + || p[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 + && p[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 (p[1] == 0 && p[2] == 0 && p[3] == 0) { + if (s->msg_callback) + s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, + p, DTLS1_HM_HEADER_LENGTH, ussl, + 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) { + p += 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; +} |