/* 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.] */ /* ==================================================================== * Copyright (c) 1998-2002 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). */ #include #include #include #include #include #include #include "internal.h" #include "../crypto/internal.h" namespace bssl { // kMaxEmptyRecords is the number of consecutive, empty records that will be // processed. Without this limit an attacker could send empty records at a // faster rate than we can process and cause record processing to loop // forever. static const uint8_t kMaxEmptyRecords = 32; // kMaxEarlyDataSkipped is the maximum number of rejected early data bytes that // will be skipped. Without this limit an attacker could send records at a // faster rate than we can process and cause trial decryption to loop forever. // This value should be slightly above kMaxEarlyDataAccepted, which is measured // in plaintext. static const size_t kMaxEarlyDataSkipped = 16384; // kMaxWarningAlerts is the number of consecutive warning alerts that will be // processed. static const uint8_t kMaxWarningAlerts = 4; // ssl_needs_record_splitting returns one if |ssl|'s current outgoing cipher // state needs record-splitting and zero otherwise. static int ssl_needs_record_splitting(const SSL *ssl) { #if !defined(BORINGSSL_UNSAFE_FUZZER_MODE) return !ssl->s3->aead_write_ctx->is_null_cipher() && ssl->s3->aead_write_ctx->ProtocolVersion() < TLS1_1_VERSION && (ssl->mode & SSL_MODE_CBC_RECORD_SPLITTING) != 0 && SSL_CIPHER_is_block_cipher(ssl->s3->aead_write_ctx->cipher()); #else return 0; #endif } int ssl_record_sequence_update(uint8_t *seq, size_t seq_len) { for (size_t i = seq_len - 1; i < seq_len; i--) { ++seq[i]; if (seq[i] != 0) { return 1; } } OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW); return 0; } size_t ssl_record_prefix_len(const SSL *ssl) { size_t header_len; if (SSL_is_dtls(ssl)) { header_len = DTLS1_RT_HEADER_LENGTH; } else { header_len = SSL3_RT_HEADER_LENGTH; } return header_len + ssl->s3->aead_read_ctx->ExplicitNonceLen(); } size_t ssl_seal_align_prefix_len(const SSL *ssl) { if (SSL_is_dtls(ssl)) { return DTLS1_RT_HEADER_LENGTH + ssl->s3->aead_write_ctx->ExplicitNonceLen(); } size_t ret = SSL3_RT_HEADER_LENGTH + ssl->s3->aead_write_ctx->ExplicitNonceLen(); if (ssl_needs_record_splitting(ssl)) { ret += SSL3_RT_HEADER_LENGTH; ret += ssl_cipher_get_record_split_len(ssl->s3->aead_write_ctx->cipher()); } return ret; } static ssl_open_record_t skip_early_data(SSL *ssl, uint8_t *out_alert, size_t consumed) { ssl->s3->early_data_skipped += consumed; if (ssl->s3->early_data_skipped < consumed) { ssl->s3->early_data_skipped = kMaxEarlyDataSkipped + 1; } if (ssl->s3->early_data_skipped > kMaxEarlyDataSkipped) { OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MUCH_SKIPPED_EARLY_DATA); *out_alert = SSL_AD_UNEXPECTED_MESSAGE; return ssl_open_record_error; } return ssl_open_record_discard; } ssl_open_record_t tls_open_record(SSL *ssl, uint8_t *out_type, Span *out, size_t *out_consumed, uint8_t *out_alert, Span in) { *out_consumed = 0; if (ssl->s3->read_shutdown == ssl_shutdown_close_notify) { return ssl_open_record_close_notify; } // If there is an unprocessed handshake message or we are already buffering // too much, stop before decrypting another handshake record. if (!tls_can_accept_handshake_data(ssl, out_alert)) { return ssl_open_record_error; } CBS cbs = CBS(in); // Decode the record header. uint8_t type; uint16_t version, ciphertext_len; if (!CBS_get_u8(&cbs, &type) || !CBS_get_u16(&cbs, &version) || !CBS_get_u16(&cbs, &ciphertext_len)) { *out_consumed = SSL3_RT_HEADER_LENGTH; return ssl_open_record_partial; } 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) == SSL3_VERSION_MAJOR; } else { version_ok = version == ssl->s3->aead_read_ctx->RecordVersion(); } if (!version_ok) { OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_VERSION_NUMBER); *out_alert = SSL_AD_PROTOCOL_VERSION; return ssl_open_record_error; } // Check the ciphertext length. if (ciphertext_len > SSL3_RT_MAX_ENCRYPTED_LENGTH) { OPENSSL_PUT_ERROR(SSL, SSL_R_ENCRYPTED_LENGTH_TOO_LONG); *out_alert = SSL_AD_RECORD_OVERFLOW; return ssl_open_record_error; } // Extract the body. CBS body; if (!CBS_get_bytes(&cbs, &body, ciphertext_len)) { *out_consumed = SSL3_RT_HEADER_LENGTH + (size_t)ciphertext_len; return ssl_open_record_partial; } ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_HEADER, in.subspan(0, SSL3_RT_HEADER_LENGTH)); *out_consumed = in.size() - CBS_len(&cbs); if (ssl->s3->have_version && ssl_protocol_version(ssl) >= TLS1_3_VERSION && SSL_in_init(ssl) && type == SSL3_RT_CHANGE_CIPHER_SPEC && ciphertext_len == 1 && CBS_data(&body)[0] == 1) { ssl->s3->empty_record_count++; if (ssl->s3->empty_record_count > kMaxEmptyRecords) { OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_EMPTY_FRAGMENTS); *out_alert = SSL_AD_UNEXPECTED_MESSAGE; return ssl_open_record_error; } return ssl_open_record_discard; } // Skip early data received when expecting a second ClientHello if we rejected // 0RTT. if (ssl->s3->skip_early_data && ssl->s3->aead_read_ctx->is_null_cipher() && type == SSL3_RT_APPLICATION_DATA) { return skip_early_data(ssl, out_alert, *out_consumed); } // Decrypt the body in-place. if (!ssl->s3->aead_read_ctx->Open( out, type, version, ssl->s3->read_sequence, MakeSpan(const_cast(CBS_data(&body)), CBS_len(&body)))) { if (ssl->s3->skip_early_data && !ssl->s3->aead_read_ctx->is_null_cipher()) { ERR_clear_error(); return skip_early_data(ssl, out_alert, *out_consumed); } OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); *out_alert = SSL_AD_BAD_RECORD_MAC; return ssl_open_record_error; } ssl->s3->skip_early_data = false; if (!ssl_record_sequence_update(ssl->s3->read_sequence, 8)) { *out_alert = SSL_AD_INTERNAL_ERROR; return ssl_open_record_error; } // TLS 1.3 hides the record type inside the encrypted data. bool has_padding = !ssl->s3->aead_read_ctx->is_null_cipher() && ssl->s3->aead_read_ctx->ProtocolVersion() >= TLS1_3_VERSION; // If there is padding, the plaintext limit includes the padding, but includes // extra room for the inner content type. size_t plaintext_limit = has_padding ? SSL3_RT_MAX_PLAIN_LENGTH + 1 : SSL3_RT_MAX_PLAIN_LENGTH; if (out->size() > plaintext_limit) { OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG); *out_alert = SSL_AD_RECORD_OVERFLOW; return ssl_open_record_error; } if (has_padding) { // The outer record type is always application_data. if (type != SSL3_RT_APPLICATION_DATA) { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_OUTER_RECORD_TYPE); *out_alert = SSL_AD_DECODE_ERROR; return ssl_open_record_error; } do { if (out->empty()) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); *out_alert = SSL_AD_DECRYPT_ERROR; return ssl_open_record_error; } type = out->back(); *out = out->subspan(0, out->size() - 1); } while (type == 0); } // Limit the number of consecutive empty records. if (out->empty()) { ssl->s3->empty_record_count++; if (ssl->s3->empty_record_count > kMaxEmptyRecords) { OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_EMPTY_FRAGMENTS); *out_alert = SSL_AD_UNEXPECTED_MESSAGE; return ssl_open_record_error; } // Apart from the limit, empty records are returned up to the caller. This // allows the caller to reject records of the wrong type. } else { ssl->s3->empty_record_count = 0; } if (type == SSL3_RT_ALERT) { return ssl_process_alert(ssl, out_alert, *out); } // Handshake messages may not interleave with any other record type. if (type != SSL3_RT_HANDSHAKE && tls_has_unprocessed_handshake_data(ssl)) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_RECORD); *out_alert = SSL_AD_UNEXPECTED_MESSAGE; return ssl_open_record_error; } ssl->s3->warning_alert_count = 0; *out_type = type; return ssl_open_record_success; } static int do_seal_record(SSL *ssl, uint8_t *out_prefix, uint8_t *out, uint8_t *out_suffix, uint8_t type, const uint8_t *in, const size_t in_len) { uint8_t *extra_in = NULL; size_t extra_in_len = 0; if (!ssl->s3->aead_write_ctx->is_null_cipher() && ssl->s3->aead_write_ctx->ProtocolVersion() >= TLS1_3_VERSION) { // TLS 1.3 hides the actual record type inside the encrypted data. extra_in = &type; extra_in_len = 1; } size_t suffix_len; if (!ssl->s3->aead_write_ctx->SuffixLen(&suffix_len, in_len, extra_in_len)) { OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE); return 0; } size_t ciphertext_len = ssl->s3->aead_write_ctx->ExplicitNonceLen() + suffix_len; if (ciphertext_len + in_len < ciphertext_len) { OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE); return 0; } ciphertext_len += in_len; assert(in == out || !buffers_alias(in, in_len, out, in_len)); assert(!buffers_alias(in, in_len, out_prefix, ssl_record_prefix_len(ssl))); assert(!buffers_alias(in, in_len, out_suffix, suffix_len)); if (extra_in_len) { out_prefix[0] = SSL3_RT_APPLICATION_DATA; } else { out_prefix[0] = type; } uint16_t record_version = ssl->s3->aead_write_ctx->RecordVersion(); out_prefix[1] = record_version >> 8; out_prefix[2] = record_version & 0xff; out_prefix[3] = ciphertext_len >> 8; out_prefix[4] = ciphertext_len & 0xff; if (!ssl->s3->aead_write_ctx->SealScatter( out_prefix + SSL3_RT_HEADER_LENGTH, out, out_suffix, type, record_version, ssl->s3->write_sequence, in, in_len, extra_in, extra_in_len) || !ssl_record_sequence_update(ssl->s3->write_sequence, 8)) { return 0; } ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_HEADER, MakeSpan(out_prefix, SSL3_RT_HEADER_LENGTH)); return 1; } static size_t tls_seal_scatter_prefix_len(const SSL *ssl, uint8_t type, size_t in_len) { size_t ret = SSL3_RT_HEADER_LENGTH; if (type == SSL3_RT_APPLICATION_DATA && in_len > 1 && ssl_needs_record_splitting(ssl)) { // In the case of record splitting, the 1-byte record (of the 1/n-1 split) // will be placed in the prefix, as will four of the five bytes of the // record header for the main record. The final byte will replace the first // byte of the plaintext that was used in the small record. ret += ssl_cipher_get_record_split_len(ssl->s3->aead_write_ctx->cipher()); ret += SSL3_RT_HEADER_LENGTH - 1; } else { ret += ssl->s3->aead_write_ctx->ExplicitNonceLen(); } return ret; } static bool tls_seal_scatter_suffix_len(const SSL *ssl, size_t *out_suffix_len, uint8_t type, size_t in_len) { size_t extra_in_len = 0; if (!ssl->s3->aead_write_ctx->is_null_cipher() && ssl->s3->aead_write_ctx->ProtocolVersion() >= TLS1_3_VERSION) { // TLS 1.3 adds an extra byte for encrypted record type. extra_in_len = 1; } if (type == SSL3_RT_APPLICATION_DATA && // clang-format off in_len > 1 && ssl_needs_record_splitting(ssl)) { // With record splitting enabled, the first byte gets sealed into a separate // record which is written into the prefix. in_len -= 1; } return ssl->s3->aead_write_ctx->SuffixLen(out_suffix_len, in_len, extra_in_len); } // tls_seal_scatter_record seals a new record of type |type| and body |in| and // splits it between |out_prefix|, |out|, and |out_suffix|. Exactly // |tls_seal_scatter_prefix_len| bytes are written to |out_prefix|, |in_len| // bytes to |out|, and |tls_seal_scatter_suffix_len| bytes to |out_suffix|. It // returns one on success and zero on error. If enabled, // |tls_seal_scatter_record| implements TLS 1.0 CBC 1/n-1 record splitting and // may write two records concatenated. static int tls_seal_scatter_record(SSL *ssl, uint8_t *out_prefix, uint8_t *out, uint8_t *out_suffix, uint8_t type, const uint8_t *in, size_t in_len) { if (type == SSL3_RT_APPLICATION_DATA && in_len > 1 && ssl_needs_record_splitting(ssl)) { assert(ssl->s3->aead_write_ctx->ExplicitNonceLen() == 0); const size_t prefix_len = SSL3_RT_HEADER_LENGTH; // Write the 1-byte fragment into |out_prefix|. uint8_t *split_body = out_prefix + prefix_len; uint8_t *split_suffix = split_body + 1; if (!do_seal_record(ssl, out_prefix, split_body, split_suffix, type, in, 1)) { return 0; } size_t split_record_suffix_len; if (!ssl->s3->aead_write_ctx->SuffixLen(&split_record_suffix_len, 1, 0)) { assert(false); return 0; } const size_t split_record_len = prefix_len + 1 + split_record_suffix_len; assert(SSL3_RT_HEADER_LENGTH + ssl_cipher_get_record_split_len( ssl->s3->aead_write_ctx->cipher()) == split_record_len); // Write the n-1-byte fragment. The header gets split between |out_prefix| // (header[:-1]) and |out| (header[-1:]). uint8_t tmp_prefix[SSL3_RT_HEADER_LENGTH]; if (!do_seal_record(ssl, tmp_prefix, out + 1, out_suffix, type, in + 1, in_len - 1)) { return 0; } assert(tls_seal_scatter_prefix_len(ssl, type, in_len) == split_record_len + SSL3_RT_HEADER_LENGTH - 1); OPENSSL_memcpy(out_prefix + split_record_len, tmp_prefix, SSL3_RT_HEADER_LENGTH - 1); OPENSSL_memcpy(out, tmp_prefix + SSL3_RT_HEADER_LENGTH - 1, 1); return 1; } return do_seal_record(ssl, out_prefix, out, out_suffix, type, in, in_len); } int tls_seal_record(SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out_len, uint8_t type, const uint8_t *in, size_t in_len) { if (buffers_alias(in, in_len, out, max_out_len)) { OPENSSL_PUT_ERROR(SSL, SSL_R_OUTPUT_ALIASES_INPUT); return 0; } const size_t prefix_len = tls_seal_scatter_prefix_len(ssl, type, in_len); size_t suffix_len; if (!tls_seal_scatter_suffix_len(ssl, &suffix_len, type, in_len)) { return false; } if (in_len + prefix_len < in_len || prefix_len + in_len + suffix_len < prefix_len + in_len) { OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE); return 0; } if (max_out_len < in_len + prefix_len + suffix_len) { OPENSSL_PUT_ERROR(SSL, SSL_R_BUFFER_TOO_SMALL); return 0; } uint8_t *prefix = out; uint8_t *body = out + prefix_len; uint8_t *suffix = body + in_len; if (!tls_seal_scatter_record(ssl, prefix, body, suffix, type, in, in_len)) { return 0; } *out_len = prefix_len + in_len + suffix_len; return 1; } enum ssl_open_record_t ssl_process_alert(SSL *ssl, uint8_t *out_alert, Span in) { // Alerts records may not contain fragmented or multiple alerts. if (in.size() != 2) { *out_alert = SSL_AD_DECODE_ERROR; OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ALERT); return ssl_open_record_error; } ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_ALERT, in); const uint8_t alert_level = in[0]; const uint8_t alert_descr = in[1]; uint16_t alert = (alert_level << 8) | alert_descr; ssl_do_info_callback(ssl, SSL_CB_READ_ALERT, alert); if (alert_level == SSL3_AL_WARNING) { if (alert_descr == SSL_AD_CLOSE_NOTIFY) { ssl->s3->read_shutdown = ssl_shutdown_close_notify; return ssl_open_record_close_notify; } // Warning alerts do not exist in TLS 1.3. if (ssl->s3->have_version && ssl_protocol_version(ssl) >= TLS1_3_VERSION) { *out_alert = SSL_AD_DECODE_ERROR; OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ALERT); return ssl_open_record_error; } ssl->s3->warning_alert_count++; if (ssl->s3->warning_alert_count > kMaxWarningAlerts) { *out_alert = SSL_AD_UNEXPECTED_MESSAGE; OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_WARNING_ALERTS); return ssl_open_record_error; } return ssl_open_record_discard; } if (alert_level == SSL3_AL_FATAL) { OPENSSL_PUT_ERROR(SSL, SSL_AD_REASON_OFFSET + alert_descr); ERR_add_error_dataf("SSL alert number %d", alert_descr); *out_alert = 0; // No alert to send back to the peer. return ssl_open_record_error; } *out_alert = SSL_AD_ILLEGAL_PARAMETER; OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_ALERT_TYPE); return ssl_open_record_error; } OpenRecordResult OpenRecord(SSL *ssl, Span *out, size_t *out_record_len, uint8_t *out_alert, const Span in) { // This API is a work in progress and currently only works for TLS 1.2 servers // and below. if (SSL_in_init(ssl) || SSL_is_dtls(ssl) || ssl_protocol_version(ssl) > TLS1_2_VERSION) { assert(false); *out_alert = SSL_AD_INTERNAL_ERROR; return OpenRecordResult::kError; } Span plaintext; uint8_t type = 0; const ssl_open_record_t result = tls_open_record( ssl, &type, &plaintext, out_record_len, out_alert, in); switch (result) { case ssl_open_record_success: if (type != SSL3_RT_APPLICATION_DATA && type != SSL3_RT_ALERT) { *out_alert = SSL_AD_UNEXPECTED_MESSAGE; return OpenRecordResult::kError; } *out = plaintext; return OpenRecordResult::kOK; case ssl_open_record_discard: return OpenRecordResult::kDiscard; case ssl_open_record_partial: return OpenRecordResult::kIncompleteRecord; case ssl_open_record_close_notify: return OpenRecordResult::kAlertCloseNotify; case ssl_open_record_error: return OpenRecordResult::kError; } assert(false); return OpenRecordResult::kError; } size_t SealRecordPrefixLen(const SSL *ssl, const size_t record_len) { return tls_seal_scatter_prefix_len(ssl, SSL3_RT_APPLICATION_DATA, record_len); } size_t SealRecordSuffixLen(const SSL *ssl, const size_t plaintext_len) { assert(plaintext_len <= SSL3_RT_MAX_PLAIN_LENGTH); size_t suffix_len; if (!tls_seal_scatter_suffix_len(ssl, &suffix_len, SSL3_RT_APPLICATION_DATA, plaintext_len)) { assert(false); OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return 0; } assert(suffix_len <= SSL3_RT_MAX_ENCRYPTED_OVERHEAD); return suffix_len; } bool SealRecord(SSL *ssl, const Span out_prefix, const Span out, Span out_suffix, const Span in) { // This API is a work in progress and currently only works for TLS 1.2 servers // and below. if (SSL_in_init(ssl) || SSL_is_dtls(ssl) || ssl_protocol_version(ssl) > TLS1_2_VERSION) { assert(false); OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return false; } if (out_prefix.size() != SealRecordPrefixLen(ssl, in.size()) || out.size() != in.size() || out_suffix.size() != SealRecordSuffixLen(ssl, in.size())) { OPENSSL_PUT_ERROR(SSL, SSL_R_BUFFER_TOO_SMALL); return false; } return tls_seal_scatter_record(ssl, out_prefix.data(), out.data(), out_suffix.data(), SSL3_RT_APPLICATION_DATA, in.data(), in.size()); } } // namespace bssl using namespace bssl; size_t SSL_max_seal_overhead(const SSL *ssl) { if (SSL_is_dtls(ssl)) { return dtls_max_seal_overhead(ssl, dtls1_use_current_epoch); } size_t ret = SSL3_RT_HEADER_LENGTH; ret += ssl->s3->aead_write_ctx->MaxOverhead(); // TLS 1.3 needs an extra byte for the encrypted record type. if (!ssl->s3->aead_write_ctx->is_null_cipher() && ssl->s3->aead_write_ctx->ProtocolVersion() >= TLS1_3_VERSION) { ret += 1; } if (ssl_needs_record_splitting(ssl)) { ret *= 2; } return ret; }