--- /dev/null
+/* 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 <openssl/ssl.h>
+
+#include <assert.h>
+#include <string.h>
+
+#include <openssl/bytestring.h>
+#include <openssl/err.h>
+
+#include "internal.h"
+#include "../crypto/internal.h"
+
+
+namespace bssl {
+
+// to_u64_be treats |in| as a 8-byte big-endian integer and returns the value as
+// a |uint64_t|.
+static uint64_t to_u64_be(const uint8_t in[8]) {
+ uint64_t ret = 0;
+ unsigned i;
+ for (i = 0; i < 8; i++) {
+ ret <<= 8;
+ ret |= in[i];
+ }
+ return ret;
+}
+
+// dtls1_bitmap_should_discard returns one if |seq_num| has been seen in
+// |bitmap| or is stale. Otherwise it returns zero.
+static int dtls1_bitmap_should_discard(DTLS1_BITMAP *bitmap,
+ const uint8_t seq_num[8]) {
+ const unsigned kWindowSize = sizeof(bitmap->map) * 8;
+
+ uint64_t seq_num_u = to_u64_be(seq_num);
+ if (seq_num_u > bitmap->max_seq_num) {
+ return 0;
+ }
+ uint64_t idx = bitmap->max_seq_num - seq_num_u;
+ return idx >= kWindowSize || (bitmap->map & (((uint64_t)1) << idx));
+}
+
+// dtls1_bitmap_record updates |bitmap| to record receipt of sequence number
+// |seq_num|. It slides the window forward if needed. It is an error to call
+// this function on a stale sequence number.
+static void dtls1_bitmap_record(DTLS1_BITMAP *bitmap,
+ const uint8_t seq_num[8]) {
+ const unsigned kWindowSize = sizeof(bitmap->map) * 8;
+
+ uint64_t seq_num_u = to_u64_be(seq_num);
+ // Shift the window if necessary.
+ if (seq_num_u > bitmap->max_seq_num) {
+ uint64_t shift = seq_num_u - bitmap->max_seq_num;
+ if (shift >= kWindowSize) {
+ bitmap->map = 0;
+ } else {
+ bitmap->map <<= shift;
+ }
+ bitmap->max_seq_num = seq_num_u;
+ }
+
+ uint64_t idx = bitmap->max_seq_num - seq_num_u;
+ if (idx < kWindowSize) {
+ bitmap->map |= ((uint64_t)1) << idx;
+ }
+}
+
+enum ssl_open_record_t dtls_open_record(SSL *ssl, uint8_t *out_type,
+ Span<uint8_t> *out,
+ size_t *out_consumed,
+ uint8_t *out_alert, Span<uint8_t> in) {
+ *out_consumed = 0;
+ if (ssl->s3->read_shutdown == ssl_shutdown_close_notify) {
+ return ssl_open_record_close_notify;
+ }
+
+ if (in.empty()) {
+ return ssl_open_record_partial;
+ }
+
+ CBS cbs = CBS(in);
+
+ // Decode the record.
+ uint8_t type;
+ uint16_t version;
+ uint8_t sequence[8];
+ CBS body;
+ if (!CBS_get_u8(&cbs, &type) ||
+ !CBS_get_u16(&cbs, &version) ||
+ !CBS_copy_bytes(&cbs, sequence, 8) ||
+ !CBS_get_u16_length_prefixed(&cbs, &body) ||
+ CBS_len(&body) > SSL3_RT_MAX_ENCRYPTED_LENGTH) {
+ // The record header was incomplete or malformed. Drop the entire packet.
+ *out_consumed = in.size();
+ return ssl_open_record_discard;
+ }
+
+ bool version_ok;
+ if (ssl->s3->aead_read_ctx->is_null_cipher()) {
+ // Only check the first byte. Enforcing beyond that can prevent decoding
+ // version negotiation failure alerts.
+ version_ok = (version >> 8) == DTLS1_VERSION_MAJOR;
+ } else {
+ version_ok = version == ssl->s3->aead_read_ctx->RecordVersion();
+ }
+
+ if (!version_ok) {
+ // The record header was incomplete or malformed. Drop the entire packet.
+ *out_consumed = in.size();
+ return ssl_open_record_discard;
+ }
+
+ ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_HEADER,
+ in.subspan(0, DTLS1_RT_HEADER_LENGTH));
+
+ uint16_t epoch = (((uint16_t)sequence[0]) << 8) | sequence[1];
+ if (epoch != ssl->d1->r_epoch ||
+ dtls1_bitmap_should_discard(&ssl->d1->bitmap, sequence)) {
+ // Drop this record. It's from the wrong epoch or is a replay. Note that if
+ // |epoch| is the next epoch, the record could be buffered for later. For
+ // simplicity, drop it and expect retransmit to handle it later; DTLS must
+ // handle packet loss anyway.
+ *out_consumed = in.size() - CBS_len(&cbs);
+ return ssl_open_record_discard;
+ }
+
+ // discard the body in-place.
+ if (!ssl->s3->aead_read_ctx->Open(
+ out, type, version, sequence,
+ MakeSpan(const_cast<uint8_t *>(CBS_data(&body)), CBS_len(&body)))) {
+ // Bad packets are silently dropped in DTLS. See section 4.2.1 of RFC 6347.
+ // Clear the error queue of any errors decryption may have added. Drop the
+ // entire packet as it must not have come from the peer.
+ //
+ // TODO(davidben): This doesn't distinguish malloc failures from encryption
+ // failures.
+ ERR_clear_error();
+ *out_consumed = in.size() - CBS_len(&cbs);
+ return ssl_open_record_discard;
+ }
+ *out_consumed = in.size() - CBS_len(&cbs);
+
+ // Check the plaintext length.
+ if (out->size() > SSL3_RT_MAX_PLAIN_LENGTH) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG);
+ *out_alert = SSL_AD_RECORD_OVERFLOW;
+ return ssl_open_record_error;
+ }
+
+ dtls1_bitmap_record(&ssl->d1->bitmap, sequence);
+
+ // TODO(davidben): Limit the number of empty records as in TLS? This is only
+ // useful if we also limit discarded packets.
+
+ if (type == SSL3_RT_ALERT) {
+ return ssl_process_alert(ssl, out_alert, *out);
+ }
+
+ ssl->s3->warning_alert_count = 0;
+
+ *out_type = type;
+ return ssl_open_record_success;
+}
+
+static const SSLAEADContext *get_write_aead(const SSL *ssl,
+ enum dtls1_use_epoch_t use_epoch) {
+ if (use_epoch == dtls1_use_previous_epoch) {
+ assert(ssl->d1->w_epoch >= 1);
+ return ssl->d1->last_aead_write_ctx.get();
+ }
+
+ return ssl->s3->aead_write_ctx.get();
+}
+
+size_t dtls_max_seal_overhead(const SSL *ssl,
+ enum dtls1_use_epoch_t use_epoch) {
+ return DTLS1_RT_HEADER_LENGTH + get_write_aead(ssl, use_epoch)->MaxOverhead();
+}
+
+size_t dtls_seal_prefix_len(const SSL *ssl, enum dtls1_use_epoch_t use_epoch) {
+ return DTLS1_RT_HEADER_LENGTH +
+ get_write_aead(ssl, use_epoch)->ExplicitNonceLen();
+}
+
+int dtls_seal_record(SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out,
+ uint8_t type, const uint8_t *in, size_t in_len,
+ enum dtls1_use_epoch_t use_epoch) {
+ const size_t prefix = dtls_seal_prefix_len(ssl, use_epoch);
+ if (buffers_alias(in, in_len, out, max_out) &&
+ (max_out < prefix || out + prefix != in)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_OUTPUT_ALIASES_INPUT);
+ return 0;
+ }
+
+ // Determine the parameters for the current epoch.
+ uint16_t epoch = ssl->d1->w_epoch;
+ SSLAEADContext *aead = ssl->s3->aead_write_ctx.get();
+ uint8_t *seq = ssl->s3->write_sequence;
+ if (use_epoch == dtls1_use_previous_epoch) {
+ assert(ssl->d1->w_epoch >= 1);
+ epoch = ssl->d1->w_epoch - 1;
+ aead = ssl->d1->last_aead_write_ctx.get();
+ seq = ssl->d1->last_write_sequence;
+ }
+
+ if (max_out < DTLS1_RT_HEADER_LENGTH) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_BUFFER_TOO_SMALL);
+ return 0;
+ }
+
+ out[0] = type;
+
+ uint16_t record_version = ssl->s3->aead_write_ctx->RecordVersion();
+ out[1] = record_version >> 8;
+ out[2] = record_version & 0xff;
+
+ out[3] = epoch >> 8;
+ out[4] = epoch & 0xff;
+ OPENSSL_memcpy(&out[5], &seq[2], 6);
+
+ size_t ciphertext_len;
+ if (!aead->Seal(out + DTLS1_RT_HEADER_LENGTH, &ciphertext_len,
+ max_out - DTLS1_RT_HEADER_LENGTH, type, record_version,
+ &out[3] /* seq */, in, in_len) ||
+ !ssl_record_sequence_update(&seq[2], 6)) {
+ return 0;
+ }
+
+ if (ciphertext_len >= 1 << 16) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
+ return 0;
+ }
+ out[11] = ciphertext_len >> 8;
+ out[12] = ciphertext_len & 0xff;
+
+ *out_len = DTLS1_RT_HEADER_LENGTH + ciphertext_len;
+
+ ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_HEADER,
+ MakeSpan(out, DTLS1_RT_HEADER_LENGTH));
+
+ return 1;
+}
+
+} // namespace bssl
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