/* * DTLS implementation written by Nagendra Modadugu * (nagendra@cs.stanford.edu) for the OpenSSL project 2005. */ /* ==================================================================== * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * openssl-core@openssl.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.openssl.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== * * This product includes cryptographic software written by Eric Young * (eay@cryptsoft.com). This product includes software written by Tim * Hudson (tjh@cryptsoft.com). * */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ #include #include #include #include #include #include #include #include #include #include #include "internal.h" /* TODO(davidben): 28 comes from the size of IP + UDP header. Is this reasonable * for these values? Notably, why is kMinMTU a function of the transport * protocol's overhead rather than, say, what's needed to hold a minimally-sized * handshake fragment plus protocol overhead. */ /* kMinMTU is the minimum acceptable MTU value. */ static const unsigned int kMinMTU = 256 - 28; /* kDefaultMTU is the default MTU value to use if neither the user nor * the underlying BIO supplies one. */ static const unsigned int kDefaultMTU = 1500 - 28; /* Receiving handshake messages. */ static void dtls1_hm_fragment_free(hm_fragment *frag) { if (frag == NULL) { return; } OPENSSL_free(frag->data); OPENSSL_free(frag->reassembly); OPENSSL_free(frag); } static hm_fragment *dtls1_hm_fragment_new(const struct hm_header_st *msg_hdr) { hm_fragment *frag = OPENSSL_malloc(sizeof(hm_fragment)); if (frag == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); return NULL; } memset(frag, 0, sizeof(hm_fragment)); frag->type = msg_hdr->type; frag->seq = msg_hdr->seq; frag->msg_len = msg_hdr->msg_len; /* Allocate space for the reassembled message and fill in the header. */ frag->data = OPENSSL_malloc(DTLS1_HM_HEADER_LENGTH + msg_hdr->msg_len); if (frag->data == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); goto err; } CBB cbb; if (!CBB_init_fixed(&cbb, frag->data, DTLS1_HM_HEADER_LENGTH) || !CBB_add_u8(&cbb, msg_hdr->type) || !CBB_add_u24(&cbb, msg_hdr->msg_len) || !CBB_add_u16(&cbb, msg_hdr->seq) || !CBB_add_u24(&cbb, 0 /* frag_off */) || !CBB_add_u24(&cbb, msg_hdr->msg_len) || !CBB_finish(&cbb, NULL, NULL)) { CBB_cleanup(&cbb); OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); goto err; } /* If the handshake message is empty, |frag->reassembly| is NULL. */ if (msg_hdr->msg_len > 0) { /* Initialize reassembly bitmask. */ if (msg_hdr->msg_len + 7 < msg_hdr->msg_len) { OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW); goto err; } size_t bitmask_len = (msg_hdr->msg_len + 7) / 8; frag->reassembly = OPENSSL_malloc(bitmask_len); if (frag->reassembly == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); goto err; } memset(frag->reassembly, 0, bitmask_len); } return frag; err: dtls1_hm_fragment_free(frag); return NULL; } /* bit_range returns a |uint8_t| with bits |start|, inclusive, to |end|, * exclusive, set. */ static uint8_t bit_range(size_t start, size_t end) { return (uint8_t)(~((1u << start) - 1) & ((1u << end) - 1)); } /* dtls1_hm_fragment_mark marks bytes |start|, inclusive, to |end|, exclusive, * as received in |frag|. If |frag| becomes complete, it clears * |frag->reassembly|. The range must be within the bounds of |frag|'s message * and |frag->reassembly| must not be NULL. */ static void dtls1_hm_fragment_mark(hm_fragment *frag, size_t start, size_t end) { size_t msg_len = frag->msg_len; if (frag->reassembly == NULL || start > end || end > msg_len) { assert(0); return; } /* A zero-length message will never have a pending reassembly. */ assert(msg_len > 0); if ((start >> 3) == (end >> 3)) { frag->reassembly[start >> 3] |= bit_range(start & 7, end & 7); } else { frag->reassembly[start >> 3] |= bit_range(start & 7, 8); for (size_t i = (start >> 3) + 1; i < (end >> 3); i++) { frag->reassembly[i] = 0xff; } if ((end & 7) != 0) { frag->reassembly[end >> 3] |= bit_range(0, end & 7); } } /* Check if the fragment is complete. */ for (size_t i = 0; i < (msg_len >> 3); i++) { if (frag->reassembly[i] != 0xff) { return; } } if ((msg_len & 7) != 0 && frag->reassembly[msg_len >> 3] != bit_range(0, msg_len & 7)) { return; } OPENSSL_free(frag->reassembly); frag->reassembly = NULL; } /* dtls1_is_current_message_complete returns one if the current handshake * message is complete and zero otherwise. */ static int dtls1_is_current_message_complete(const SSL *ssl) { hm_fragment *frag = ssl->d1->incoming_messages[ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT]; return frag != NULL && frag->reassembly == NULL; } /* dtls1_get_incoming_message returns the incoming message corresponding to * |msg_hdr|. If none exists, it creates a new one and inserts it in the * queue. Otherwise, it checks |msg_hdr| is consistent with the existing one. It * returns NULL on failure. The caller does not take ownership of the result. */ static hm_fragment *dtls1_get_incoming_message( SSL *ssl, const struct hm_header_st *msg_hdr) { if (msg_hdr->seq < ssl->d1->handshake_read_seq || msg_hdr->seq - ssl->d1->handshake_read_seq >= SSL_MAX_HANDSHAKE_FLIGHT) { return NULL; } size_t idx = msg_hdr->seq % SSL_MAX_HANDSHAKE_FLIGHT; hm_fragment *frag = ssl->d1->incoming_messages[idx]; if (frag != NULL) { assert(frag->seq == msg_hdr->seq); /* The new fragment must be compatible with the previous fragments from this * message. */ if (frag->type != msg_hdr->type || frag->msg_len != msg_hdr->msg_len) { OPENSSL_PUT_ERROR(SSL, SSL_R_FRAGMENT_MISMATCH); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return NULL; } return frag; } /* This is the first fragment from this message. */ frag = dtls1_hm_fragment_new(msg_hdr); if (frag == NULL) { return NULL; } ssl->d1->incoming_messages[idx] = frag; return frag; } /* dtls1_process_handshake_record reads a handshake record and processes it. It * returns one if the record was successfully processed and 0 or -1 on error. */ static int dtls1_process_handshake_record(SSL *ssl) { SSL3_RECORD *rr = &ssl->s3->rrec; start: if (rr->length == 0) { int ret = dtls1_get_record(ssl); if (ret <= 0) { return ret; } } /* Cross-epoch records are discarded, but we may receive out-of-order * application data between ChangeCipherSpec and Finished or a ChangeCipherSpec * before the appropriate point in the handshake. Those must be silently * discarded. * * However, only allow the out-of-order records in the correct epoch. * Application data must come in the encrypted epoch, and ChangeCipherSpec in * the unencrypted epoch (we never renegotiate). Other cases fall through and * fail with a fatal error. */ if ((rr->type == SSL3_RT_APPLICATION_DATA && ssl->s3->aead_read_ctx != NULL) || (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC && ssl->s3->aead_read_ctx == NULL)) { rr->length = 0; goto start; } if (rr->type != SSL3_RT_HANDSHAKE) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD); return -1; } CBS cbs; CBS_init(&cbs, rr->data, rr->length); while (CBS_len(&cbs) > 0) { /* Read a handshake fragment. */ struct hm_header_st msg_hdr; CBS body; if (!dtls1_parse_fragment(&cbs, &msg_hdr, &body)) { OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_HANDSHAKE_RECORD); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return -1; } const size_t frag_off = msg_hdr.frag_off; const size_t frag_len = msg_hdr.frag_len; const size_t msg_len = msg_hdr.msg_len; if (frag_off > msg_len || frag_off + frag_len < frag_off || frag_off + frag_len > msg_len || msg_len > ssl_max_handshake_message_len(ssl)) { OPENSSL_PUT_ERROR(SSL, SSL_R_EXCESSIVE_MESSAGE_SIZE); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); return -1; } /* The encrypted epoch in DTLS has only one handshake message. */ if (ssl->d1->r_epoch == 1 && msg_hdr.seq != ssl->d1->handshake_read_seq) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); return -1; } if (msg_hdr.seq < ssl->d1->handshake_read_seq || msg_hdr.seq > (unsigned)ssl->d1->handshake_read_seq + SSL_MAX_HANDSHAKE_FLIGHT) { /* Ignore fragments from the past, or ones too far in the future. */ continue; } hm_fragment *frag = dtls1_get_incoming_message(ssl, &msg_hdr); if (frag == NULL) { return -1; } assert(frag->msg_len == msg_len); if (frag->reassembly == NULL) { /* The message is already assembled. */ continue; } assert(msg_len > 0); /* Copy the body into the fragment. */ memcpy(frag->data + DTLS1_HM_HEADER_LENGTH + frag_off, CBS_data(&body), CBS_len(&body)); dtls1_hm_fragment_mark(frag, frag_off, frag_off + frag_len); } rr->length = 0; ssl_read_buffer_discard(ssl); return 1; } int dtls1_get_message(SSL *ssl, int msg_type, enum ssl_hash_message_t hash_message) { if (ssl->s3->tmp.reuse_message) { /* A ssl_dont_hash_message call cannot be combined with reuse_message; the * ssl_dont_hash_message would have to have been applied to the previous * call. */ assert(hash_message == ssl_hash_message); assert(ssl->init_msg != NULL); ssl->s3->tmp.reuse_message = 0; hash_message = ssl_dont_hash_message; } else { dtls1_release_current_message(ssl, 0 /* don't free buffer */); } /* Process handshake records until the current message is ready. */ while (!dtls1_is_current_message_complete(ssl)) { int ret = dtls1_process_handshake_record(ssl); if (ret <= 0) { return ret; } } hm_fragment *frag = ssl->d1->incoming_messages[ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT]; assert(frag != NULL); assert(frag->reassembly == NULL); assert(ssl->d1->handshake_read_seq == frag->seq); /* TODO(davidben): This function has a lot of implicit outputs. Simplify the * |ssl_get_message| API. */ ssl->s3->tmp.message_type = frag->type; ssl->init_msg = frag->data + DTLS1_HM_HEADER_LENGTH; ssl->init_num = frag->msg_len; if (msg_type >= 0 && ssl->s3->tmp.message_type != msg_type) { ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE); return -1; } if (hash_message == ssl_hash_message && !dtls1_hash_current_message(ssl)) { return -1; } ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_HANDSHAKE, frag->data, ssl->init_num + DTLS1_HM_HEADER_LENGTH); return 1; } int dtls1_hash_current_message(SSL *ssl) { assert(dtls1_is_current_message_complete(ssl)); hm_fragment *frag = ssl->d1->incoming_messages[ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT]; return ssl3_update_handshake_hash(ssl, frag->data, DTLS1_HM_HEADER_LENGTH + frag->msg_len); } void dtls1_release_current_message(SSL *ssl, int free_buffer) { if (ssl->init_msg == NULL) { return; } assert(dtls1_is_current_message_complete(ssl)); size_t index = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT; dtls1_hm_fragment_free(ssl->d1->incoming_messages[index]); ssl->d1->incoming_messages[index] = NULL; ssl->d1->handshake_read_seq++; ssl->init_msg = NULL; ssl->init_num = 0; } void dtls_clear_incoming_messages(SSL *ssl) { for (size_t i = 0; i < SSL_MAX_HANDSHAKE_FLIGHT; i++) { dtls1_hm_fragment_free(ssl->d1->incoming_messages[i]); ssl->d1->incoming_messages[i] = NULL; } } int dtls_has_incoming_messages(const SSL *ssl) { size_t current = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT; for (size_t i = 0; i < SSL_MAX_HANDSHAKE_FLIGHT; i++) { /* Skip the current message. */ if (ssl->init_msg != NULL && i == current) { assert(dtls1_is_current_message_complete(ssl)); continue; } if (ssl->d1->incoming_messages[i] != NULL) { return 1; } } return 0; } int dtls1_parse_fragment(CBS *cbs, struct hm_header_st *out_hdr, CBS *out_body) { memset(out_hdr, 0x00, sizeof(struct hm_header_st)); if (!CBS_get_u8(cbs, &out_hdr->type) || !CBS_get_u24(cbs, &out_hdr->msg_len) || !CBS_get_u16(cbs, &out_hdr->seq) || !CBS_get_u24(cbs, &out_hdr->frag_off) || !CBS_get_u24(cbs, &out_hdr->frag_len) || !CBS_get_bytes(cbs, out_body, out_hdr->frag_len)) { return 0; } return 1; } /* Sending handshake messages. */ static void dtls1_update_mtu(SSL *ssl) { /* TODO(davidben): What is this code doing and do we need it? */ if (ssl->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) { long mtu = BIO_ctrl(ssl->wbio, BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL); if (mtu >= 0 && mtu <= (1 << 30) && (unsigned)mtu >= dtls1_min_mtu()) { ssl->d1->mtu = (unsigned)mtu; } else { ssl->d1->mtu = kDefaultMTU; BIO_ctrl(ssl->wbio, BIO_CTRL_DGRAM_SET_MTU, ssl->d1->mtu, NULL); } } /* The MTU should be above the minimum now. */ assert(ssl->d1->mtu >= dtls1_min_mtu()); } /* dtls1_max_record_size returns the maximum record body length that may be * written without exceeding the MTU. It accounts for any buffering installed on * the write BIO. If no record may be written, it returns zero. */ static size_t dtls1_max_record_size(SSL *ssl) { size_t ret = ssl->d1->mtu; size_t overhead = ssl_max_seal_overhead(ssl); if (ret <= overhead) { return 0; } ret -= overhead; size_t pending = BIO_wpending(ssl->wbio); if (ret <= pending) { return 0; } ret -= pending; return ret; } static int dtls1_write_change_cipher_spec(SSL *ssl, enum dtls1_use_epoch_t use_epoch) { dtls1_update_mtu(ssl); /* During the handshake, wbio is buffered to pack messages together. Flush the * buffer if the ChangeCipherSpec would not fit in a packet. */ if (dtls1_max_record_size(ssl) == 0) { int ret = BIO_flush(ssl->wbio); if (ret <= 0) { ssl->rwstate = SSL_WRITING; return ret; } } static const uint8_t kChangeCipherSpec[1] = {SSL3_MT_CCS}; int ret = dtls1_write_record(ssl, SSL3_RT_CHANGE_CIPHER_SPEC, kChangeCipherSpec, sizeof(kChangeCipherSpec), use_epoch); if (ret <= 0) { return ret; } ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_CHANGE_CIPHER_SPEC, kChangeCipherSpec, sizeof(kChangeCipherSpec)); return 1; } /* dtls1_do_handshake_write writes handshake message |in| using the given epoch, * starting |offset| bytes into the message body. It returns one on success. On * error, it returns <= 0 and sets |*out_offset| to the number of bytes of body * that were successfully written. This may be used to retry the write * later. |in| must be a reassembled handshake message with the full DTLS * handshake header. */ static int dtls1_do_handshake_write(SSL *ssl, size_t *out_offset, const uint8_t *in, size_t offset, size_t len, enum dtls1_use_epoch_t use_epoch) { dtls1_update_mtu(ssl); int ret = -1; CBB cbb; CBB_zero(&cbb); /* Allocate a temporary buffer to hold the message fragments to avoid * clobbering the message. */ uint8_t *buf = OPENSSL_malloc(ssl->d1->mtu); if (buf == NULL) { goto err; } /* Although it may be sent as multiple fragments, a DTLS message must be sent * serialized as a single fragment for purposes of |ssl_do_msg_callback| and * the handshake hash. */ CBS cbs, body; struct hm_header_st hdr; CBS_init(&cbs, in, len); if (!dtls1_parse_fragment(&cbs, &hdr, &body) || hdr.frag_off != 0 || hdr.frag_len != CBS_len(&body) || hdr.msg_len != CBS_len(&body) || !CBS_skip(&body, offset) || CBS_len(&cbs) != 0) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); goto err; } do { /* During the handshake, wbio is buffered to pack messages together. Flush * the buffer if there isn't enough room to make progress. */ if (dtls1_max_record_size(ssl) < DTLS1_HM_HEADER_LENGTH + 1) { int flush_ret = BIO_flush(ssl->wbio); if (flush_ret <= 0) { ssl->rwstate = SSL_WRITING; ret = flush_ret; goto err; } assert(BIO_wpending(ssl->wbio) == 0); } size_t todo = dtls1_max_record_size(ssl); if (todo < DTLS1_HM_HEADER_LENGTH + 1) { /* To make forward progress, the MTU must, at minimum, fit the handshake * header and one byte of handshake body. */ OPENSSL_PUT_ERROR(SSL, SSL_R_MTU_TOO_SMALL); goto err; } todo -= DTLS1_HM_HEADER_LENGTH; if (todo > CBS_len(&body)) { todo = CBS_len(&body); } if (todo >= (1u << 24)) { todo = (1u << 24) - 1; } size_t buf_len; if (!CBB_init_fixed(&cbb, buf, ssl->d1->mtu) || !CBB_add_u8(&cbb, hdr.type) || !CBB_add_u24(&cbb, hdr.msg_len) || !CBB_add_u16(&cbb, hdr.seq) || !CBB_add_u24(&cbb, offset) || !CBB_add_u24(&cbb, todo) || !CBB_add_bytes(&cbb, CBS_data(&body), todo) || !CBB_finish(&cbb, NULL, &buf_len)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); goto err; } int write_ret = dtls1_write_record(ssl, SSL3_RT_HANDSHAKE, buf, buf_len, use_epoch); if (write_ret <= 0) { ret = write_ret; goto err; } if (!CBS_skip(&body, todo)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); goto err; } offset += todo; } while (CBS_len(&body) != 0); ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_HANDSHAKE, in, len); ret = 1; err: *out_offset = offset; CBB_cleanup(&cbb); OPENSSL_free(buf); return ret; } void dtls_clear_outgoing_messages(SSL *ssl) { for (size_t i = 0; i < ssl->d1->outgoing_messages_len; i++) { OPENSSL_free(ssl->d1->outgoing_messages[i].data); ssl->d1->outgoing_messages[i].data = NULL; } ssl->d1->outgoing_messages_len = 0; } /* dtls1_add_change_cipher_spec adds a ChangeCipherSpec to the current * handshake flight. */ static int dtls1_add_change_cipher_spec(SSL *ssl) { if (ssl->d1->outgoing_messages_len >= SSL_MAX_HANDSHAKE_FLIGHT) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return 0; } DTLS_OUTGOING_MESSAGE *msg = &ssl->d1->outgoing_messages[ssl->d1->outgoing_messages_len]; msg->data = NULL; msg->len = 0; msg->epoch = ssl->d1->w_epoch; msg->is_ccs = 1; ssl->d1->outgoing_messages_len++; return 1; } static int dtls1_add_message(SSL *ssl, uint8_t *data, size_t len) { if (ssl->d1->outgoing_messages_len >= SSL_MAX_HANDSHAKE_FLIGHT) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); OPENSSL_free(data); return 0; } DTLS_OUTGOING_MESSAGE *msg = &ssl->d1->outgoing_messages[ssl->d1->outgoing_messages_len]; msg->data = data; msg->len = len; msg->epoch = ssl->d1->w_epoch; msg->is_ccs = 0; ssl->d1->outgoing_messages_len++; return 1; } int dtls1_init_message(SSL *ssl, CBB *cbb, CBB *body, uint8_t type) { /* Pick a modest size hint to save most of the |realloc| calls. */ if (!CBB_init(cbb, 64) || !CBB_add_u8(cbb, type) || !CBB_add_u24(cbb, 0 /* length (filled in later) */) || !CBB_add_u16(cbb, ssl->d1->handshake_write_seq) || !CBB_add_u24(cbb, 0 /* offset */) || !CBB_add_u24_length_prefixed(cbb, body)) { return 0; } return 1; } int dtls1_finish_message(SSL *ssl, CBB *cbb) { uint8_t *msg = NULL; size_t len; if (!CBB_finish(cbb, &msg, &len) || len > 0xffffffffu || len < DTLS1_HM_HEADER_LENGTH) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); OPENSSL_free(msg); return 0; } /* Fix up the header. Copy the fragment length into the total message * length. */ memcpy(msg + 1, msg + DTLS1_HM_HEADER_LENGTH - 3, 3); ssl3_update_handshake_hash(ssl, msg, len); ssl->d1->handshake_write_seq++; ssl->init_off = 0; return dtls1_add_message(ssl, msg, len); } int dtls1_write_message(SSL *ssl) { if (ssl->d1->outgoing_messages_len == 0) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return -1; } const DTLS_OUTGOING_MESSAGE *msg = &ssl->d1->outgoing_messages[ssl->d1->outgoing_messages_len - 1]; if (msg->is_ccs) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return -1; } size_t offset = ssl->init_off; int ret = dtls1_do_handshake_write(ssl, &offset, msg->data, offset, msg->len, dtls1_use_current_epoch); ssl->init_off = offset; return ret; } static int dtls1_retransmit_message(SSL *ssl, const DTLS_OUTGOING_MESSAGE *msg) { /* DTLS renegotiation is unsupported, so only epochs 0 (NULL cipher) and 1 * (negotiated cipher) exist. */ assert(ssl->d1->w_epoch == 0 || ssl->d1->w_epoch == 1); assert(msg->epoch <= ssl->d1->w_epoch); enum dtls1_use_epoch_t use_epoch = dtls1_use_current_epoch; if (ssl->d1->w_epoch == 1 && msg->epoch == 0) { use_epoch = dtls1_use_previous_epoch; } /* TODO(davidben): This cannot handle non-blocking writes. */ int ret; if (msg->is_ccs) { ret = dtls1_write_change_cipher_spec(ssl, use_epoch); } else { size_t offset = 0; ret = dtls1_do_handshake_write(ssl, &offset, msg->data, offset, msg->len, use_epoch); } return ret; } int dtls1_retransmit_outgoing_messages(SSL *ssl) { /* Ensure we are packing handshake messages. */ const int was_buffered = ssl_is_wbio_buffered(ssl); assert(was_buffered == SSL_in_init(ssl)); if (!was_buffered && !ssl_init_wbio_buffer(ssl)) { return -1; } assert(ssl_is_wbio_buffered(ssl)); int ret = -1; for (size_t i = 0; i < ssl->d1->outgoing_messages_len; i++) { if (dtls1_retransmit_message(ssl, &ssl->d1->outgoing_messages[i]) <= 0) { goto err; } } ret = BIO_flush(ssl->wbio); if (ret <= 0) { ssl->rwstate = SSL_WRITING; goto err; } err: if (!was_buffered) { ssl_free_wbio_buffer(ssl); } return ret; } int dtls1_send_change_cipher_spec(SSL *ssl) { int ret = dtls1_write_change_cipher_spec(ssl, dtls1_use_current_epoch); if (ret <= 0) { return ret; } dtls1_add_change_cipher_spec(ssl); return 1; } unsigned int dtls1_min_mtu(void) { return kMinMTU; }