/* * 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 "../crypto/internal.h" #include "internal.h" BSSL_NAMESPACE_BEGIN // 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. hm_fragment::~hm_fragment() { OPENSSL_free(data); OPENSSL_free(reassembly); } static UniquePtr dtls1_hm_fragment_new( const struct hm_header_st *msg_hdr) { ScopedCBB cbb; UniquePtr frag = MakeUnique(); if (!frag) { return nullptr; } 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 = (uint8_t *)OPENSSL_malloc(DTLS1_HM_HEADER_LENGTH + msg_hdr->msg_len); if (frag->data == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); return nullptr; } if (!CBB_init_fixed(cbb.get(), frag->data, DTLS1_HM_HEADER_LENGTH) || !CBB_add_u8(cbb.get(), msg_hdr->type) || !CBB_add_u24(cbb.get(), msg_hdr->msg_len) || !CBB_add_u16(cbb.get(), msg_hdr->seq) || !CBB_add_u24(cbb.get(), 0 /* frag_off */) || !CBB_add_u24(cbb.get(), msg_hdr->msg_len) || !CBB_finish(cbb.get(), NULL, NULL)) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); return nullptr; } // 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); return nullptr; } size_t bitmask_len = (msg_hdr->msg_len + 7) / 8; frag->reassembly = (uint8_t *)OPENSSL_malloc(bitmask_len); if (frag->reassembly == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); return nullptr; } OPENSSL_memset(frag->reassembly, 0, bitmask_len); } return frag; } // 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 == end) { return; } 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 whether the current handshake // message is complete. static bool dtls1_is_current_message_complete(const SSL *ssl) { size_t idx = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT; hm_fragment *frag = ssl->d1->incoming_messages[idx].get(); 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, uint8_t *out_alert, 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) { *out_alert = SSL_AD_INTERNAL_ERROR; return NULL; } size_t idx = msg_hdr->seq % SSL_MAX_HANDSHAKE_FLIGHT; hm_fragment *frag = ssl->d1->incoming_messages[idx].get(); 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); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return NULL; } return frag; } // This is the first fragment from this message. ssl->d1->incoming_messages[idx] = dtls1_hm_fragment_new(msg_hdr); if (!ssl->d1->incoming_messages[idx]) { *out_alert = SSL_AD_INTERNAL_ERROR; return NULL; } return ssl->d1->incoming_messages[idx].get(); } ssl_open_record_t dtls1_open_handshake(SSL *ssl, size_t *out_consumed, uint8_t *out_alert, Span in) { uint8_t type; Span record; auto ret = dtls_open_record(ssl, &type, &record, out_consumed, out_alert, in); if (ret != ssl_open_record_success) { return ret; } switch (type) { case SSL3_RT_APPLICATION_DATA: // Unencrypted application data records are always illegal. if (ssl->s3->aead_read_ctx->is_null_cipher()) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD); *out_alert = SSL_AD_UNEXPECTED_MESSAGE; return ssl_open_record_error; } // Out-of-order application data may be received between ChangeCipherSpec // and finished. Discard it. return ssl_open_record_discard; case SSL3_RT_CHANGE_CIPHER_SPEC: // We do not support renegotiation, so encrypted ChangeCipherSpec records // are illegal. if (!ssl->s3->aead_read_ctx->is_null_cipher()) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD); *out_alert = SSL_AD_UNEXPECTED_MESSAGE; return ssl_open_record_error; } if (record.size() != 1u || record[0] != SSL3_MT_CCS) { OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_CHANGE_CIPHER_SPEC); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return ssl_open_record_error; } // Flag the ChangeCipherSpec for later. ssl->d1->has_change_cipher_spec = true; ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_CHANGE_CIPHER_SPEC, record); return ssl_open_record_success; case SSL3_RT_HANDSHAKE: // Break out to main processing. break; default: OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD); *out_alert = SSL_AD_UNEXPECTED_MESSAGE; return ssl_open_record_error; } CBS cbs; CBS_init(&cbs, record.data(), record.size()); 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); *out_alert = SSL_AD_DECODE_ERROR; return ssl_open_record_error; } 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); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return ssl_open_record_error; } // 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); *out_alert = SSL_AD_UNEXPECTED_MESSAGE; return ssl_open_record_error; } 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, out_alert, &msg_hdr); if (frag == NULL) { return ssl_open_record_error; } 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. OPENSSL_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); } return ssl_open_record_success; } bool dtls1_get_message(const SSL *ssl, SSLMessage *out) { if (!dtls1_is_current_message_complete(ssl)) { return false; } size_t idx = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT; hm_fragment *frag = ssl->d1->incoming_messages[idx].get(); out->type = frag->type; CBS_init(&out->body, frag->data + DTLS1_HM_HEADER_LENGTH, frag->msg_len); CBS_init(&out->raw, frag->data, DTLS1_HM_HEADER_LENGTH + frag->msg_len); out->is_v2_hello = false; if (!ssl->s3->has_message) { ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_HANDSHAKE, out->raw); ssl->s3->has_message = true; } return true; } void dtls1_next_message(SSL *ssl) { assert(ssl->s3->has_message); assert(dtls1_is_current_message_complete(ssl)); size_t index = ssl->d1->handshake_read_seq % SSL_MAX_HANDSHAKE_FLIGHT; ssl->d1->incoming_messages[index].reset(); ssl->d1->handshake_read_seq++; ssl->s3->has_message = false; // If we previously sent a flight, mark it as having a reply, so // |on_handshake_complete| can manage post-handshake retransmission. if (ssl->d1->outgoing_messages_complete) { ssl->d1->flight_has_reply = true; } } bool dtls_has_unprocessed_handshake_data(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->s3->has_message && i == current) { assert(dtls1_is_current_message_complete(ssl)); continue; } if (ssl->d1->incoming_messages[i] != nullptr) { return true; } } return false; } bool dtls1_parse_fragment(CBS *cbs, struct hm_header_st *out_hdr, CBS *out_body) { OPENSSL_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 false; } return true; } ssl_open_record_t dtls1_open_change_cipher_spec(SSL *ssl, size_t *out_consumed, uint8_t *out_alert, Span in) { if (!ssl->d1->has_change_cipher_spec) { // dtls1_open_handshake processes both handshake and ChangeCipherSpec. auto ret = dtls1_open_handshake(ssl, out_consumed, out_alert, in); if (ret != ssl_open_record_success) { return ret; } } if (ssl->d1->has_change_cipher_spec) { ssl->d1->has_change_cipher_spec = false; return ssl_open_record_success; } return ssl_open_record_discard; } // Sending handshake messages. void DTLS_OUTGOING_MESSAGE::Clear() { OPENSSL_free(data); data = nullptr; } void dtls_clear_outgoing_messages(SSL *ssl) { for (size_t i = 0; i < ssl->d1->outgoing_messages_len; i++) { ssl->d1->outgoing_messages[i].Clear(); } ssl->d1->outgoing_messages_len = 0; ssl->d1->outgoing_written = 0; ssl->d1->outgoing_offset = 0; ssl->d1->outgoing_messages_complete = false; ssl->d1->flight_has_reply = false; } bool dtls1_init_message(const 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 false; } return true; } bool dtls1_finish_message(const SSL *ssl, CBB *cbb, Array *out_msg) { if (!CBBFinishArray(cbb, out_msg) || out_msg->size() < DTLS1_HM_HEADER_LENGTH) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return false; } // Fix up the header. Copy the fragment length into the total message // length. OPENSSL_memcpy(out_msg->data() + 1, out_msg->data() + DTLS1_HM_HEADER_LENGTH - 3, 3); return true; } // ssl_size_t_greater_than_32_bits returns whether |v| exceeds the bounds of a // 32-bit value. The obvious thing doesn't work because, in some 32-bit build // configurations, the compiler warns that the test is always false and breaks // the build. static bool ssl_size_t_greater_than_32_bits(size_t v) { #if defined(OPENSSL_64_BIT) return v > 0xffffffff; #elif defined(OPENSSL_32_BIT) return false; #else #error "Building for neither 32- nor 64-bits." #endif } // add_outgoing adds a new handshake message or ChangeCipherSpec to the current // outgoing flight. It returns true on success and false on error. static bool add_outgoing(SSL *ssl, bool is_ccs, Array data) { if (ssl->d1->outgoing_messages_complete) { // If we've begun writing a new flight, we received the peer flight. Discard // the timer and the our flight. dtls1_stop_timer(ssl); dtls_clear_outgoing_messages(ssl); } static_assert(SSL_MAX_HANDSHAKE_FLIGHT < (1 << 8 * sizeof(ssl->d1->outgoing_messages_len)), "outgoing_messages_len is too small"); if (ssl->d1->outgoing_messages_len >= SSL_MAX_HANDSHAKE_FLIGHT || ssl_size_t_greater_than_32_bits(data.size())) { assert(false); OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return false; } if (!is_ccs) { // TODO(svaldez): Move this up a layer to fix abstraction for SSLTranscript // on hs. if (ssl->s3->hs != NULL && !ssl->s3->hs->transcript.Update(data)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return false; } ssl->d1->handshake_write_seq++; } DTLS_OUTGOING_MESSAGE *msg = &ssl->d1->outgoing_messages[ssl->d1->outgoing_messages_len]; size_t len; data.Release(&msg->data, &len); msg->len = len; msg->epoch = ssl->d1->w_epoch; msg->is_ccs = is_ccs; ssl->d1->outgoing_messages_len++; return true; } bool dtls1_add_message(SSL *ssl, Array data) { return add_outgoing(ssl, false /* handshake */, std::move(data)); } bool dtls1_add_change_cipher_spec(SSL *ssl) { return add_outgoing(ssl, true /* ChangeCipherSpec */, Array()); } // dtls1_update_mtu updates the current MTU from the BIO, ensuring it is above // the minimum. static void dtls1_update_mtu(SSL *ssl) { // TODO(davidben): No consumer implements |BIO_CTRL_DGRAM_SET_MTU| and the // only |BIO_CTRL_DGRAM_QUERY_MTU| implementation could use // |SSL_set_mtu|. Does this need to be so complex? if (ssl->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(ssl) & SSL_OP_NO_QUERY_MTU)) { long mtu = BIO_ctrl(ssl->wbio.get(), 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.get(), BIO_CTRL_DGRAM_SET_MTU, ssl->d1->mtu, NULL); } } // The MTU should be above the minimum now. assert(ssl->d1->mtu >= dtls1_min_mtu()); } enum seal_result_t { seal_error, seal_no_progress, seal_partial, seal_success, }; // seal_next_message seals |msg|, which must be the next message, to |out|. If // progress was made, it returns |seal_partial| or |seal_success| and sets // |*out_len| to the number of bytes written. static enum seal_result_t seal_next_message(SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out, const DTLS_OUTGOING_MESSAGE *msg) { assert(ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len); assert(msg == &ssl->d1->outgoing_messages[ssl->d1->outgoing_written]); enum dtls1_use_epoch_t use_epoch = dtls1_use_current_epoch; if (ssl->d1->w_epoch >= 1 && msg->epoch == ssl->d1->w_epoch - 1) { use_epoch = dtls1_use_previous_epoch; } else if (msg->epoch != ssl->d1->w_epoch) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return seal_error; } size_t overhead = dtls_max_seal_overhead(ssl, use_epoch); size_t prefix = dtls_seal_prefix_len(ssl, use_epoch); if (msg->is_ccs) { // Check there is room for the ChangeCipherSpec. static const uint8_t kChangeCipherSpec[1] = {SSL3_MT_CCS}; if (max_out < sizeof(kChangeCipherSpec) + overhead) { return seal_no_progress; } if (!dtls_seal_record(ssl, out, out_len, max_out, SSL3_RT_CHANGE_CIPHER_SPEC, kChangeCipherSpec, sizeof(kChangeCipherSpec), use_epoch)) { return seal_error; } ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_CHANGE_CIPHER_SPEC, kChangeCipherSpec); return seal_success; } // DTLS messages are serialized as a single fragment in |msg|. CBS cbs, body; struct hm_header_st hdr; CBS_init(&cbs, msg->data, msg->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, ssl->d1->outgoing_offset) || CBS_len(&cbs) != 0) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return seal_error; } // Determine how much progress can be made. if (max_out < DTLS1_HM_HEADER_LENGTH + 1 + overhead || max_out < prefix) { return seal_no_progress; } size_t todo = CBS_len(&body); if (todo > max_out - DTLS1_HM_HEADER_LENGTH - overhead) { todo = max_out - DTLS1_HM_HEADER_LENGTH - overhead; } // Assemble a fragment, to be sealed in-place. ScopedCBB cbb; uint8_t *frag = out + prefix; size_t max_frag = max_out - prefix, frag_len; if (!CBB_init_fixed(cbb.get(), frag, max_frag) || !CBB_add_u8(cbb.get(), hdr.type) || !CBB_add_u24(cbb.get(), hdr.msg_len) || !CBB_add_u16(cbb.get(), hdr.seq) || !CBB_add_u24(cbb.get(), ssl->d1->outgoing_offset) || !CBB_add_u24(cbb.get(), todo) || !CBB_add_bytes(cbb.get(), CBS_data(&body), todo) || !CBB_finish(cbb.get(), NULL, &frag_len)) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return seal_error; } ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_HANDSHAKE, MakeSpan(frag, frag_len)); if (!dtls_seal_record(ssl, out, out_len, max_out, SSL3_RT_HANDSHAKE, out + prefix, frag_len, use_epoch)) { return seal_error; } if (todo == CBS_len(&body)) { // The next message is complete. ssl->d1->outgoing_offset = 0; return seal_success; } ssl->d1->outgoing_offset += todo; return seal_partial; } // seal_next_packet writes as much of the next flight as possible to |out| and // advances |ssl->d1->outgoing_written| and |ssl->d1->outgoing_offset| as // appropriate. static bool seal_next_packet(SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out) { bool made_progress = false; size_t total = 0; assert(ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len); for (; ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len; ssl->d1->outgoing_written++) { const DTLS_OUTGOING_MESSAGE *msg = &ssl->d1->outgoing_messages[ssl->d1->outgoing_written]; size_t len; enum seal_result_t ret = seal_next_message(ssl, out, &len, max_out, msg); switch (ret) { case seal_error: return false; case seal_no_progress: goto packet_full; case seal_partial: case seal_success: out += len; max_out -= len; total += len; made_progress = true; if (ret == seal_partial) { goto packet_full; } break; } } packet_full: // The MTU was too small to make any progress. if (!made_progress) { OPENSSL_PUT_ERROR(SSL, SSL_R_MTU_TOO_SMALL); return false; } *out_len = total; return true; } static int send_flight(SSL *ssl) { if (ssl->s3->write_shutdown != ssl_shutdown_none) { OPENSSL_PUT_ERROR(SSL, SSL_R_PROTOCOL_IS_SHUTDOWN); return -1; } if (ssl->wbio == nullptr) { OPENSSL_PUT_ERROR(SSL, SSL_R_BIO_NOT_SET); return -1; } dtls1_update_mtu(ssl); Array packet; if (!packet.Init(ssl->d1->mtu)) { return -1; } while (ssl->d1->outgoing_written < ssl->d1->outgoing_messages_len) { uint8_t old_written = ssl->d1->outgoing_written; uint32_t old_offset = ssl->d1->outgoing_offset; size_t packet_len; if (!seal_next_packet(ssl, packet.data(), &packet_len, packet.size())) { return -1; } int bio_ret = BIO_write(ssl->wbio.get(), packet.data(), packet_len); if (bio_ret <= 0) { // Retry this packet the next time around. ssl->d1->outgoing_written = old_written; ssl->d1->outgoing_offset = old_offset; ssl->s3->rwstate = SSL_ERROR_WANT_WRITE; return bio_ret; } } if (BIO_flush(ssl->wbio.get()) <= 0) { ssl->s3->rwstate = SSL_ERROR_WANT_WRITE; return -1; } return 1; } int dtls1_flush_flight(SSL *ssl) { ssl->d1->outgoing_messages_complete = true; // Start the retransmission timer for the next flight (if any). dtls1_start_timer(ssl); return send_flight(ssl); } int dtls1_retransmit_outgoing_messages(SSL *ssl) { // Rewind to the start of the flight and write it again. // // TODO(davidben): This does not allow retransmits to be resumed on // non-blocking write. ssl->d1->outgoing_written = 0; ssl->d1->outgoing_offset = 0; return send_flight(ssl); } unsigned int dtls1_min_mtu(void) { return kMinMTU; } BSSL_NAMESPACE_END