1/* 2 * Copyright 2016-2022 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10#include "../ssl_local.h" 11#include "record_local.h" 12#include "internal/cryptlib.h" 13 14/*- 15 * tls13_enc encrypts/decrypts |n_recs| in |recs|. Calls SSLfatal on internal 16 * error, but not otherwise. It is the responsibility of the caller to report 17 * a bad_record_mac. 18 * 19 * Returns: 20 * 0: On failure 21 * 1: if the record encryption/decryption was successful. 22 */ 23int tls13_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending, 24 ossl_unused SSL_MAC_BUF *mac, ossl_unused size_t macsize) 25{ 26 EVP_CIPHER_CTX *ctx; 27 unsigned char iv[EVP_MAX_IV_LENGTH], recheader[SSL3_RT_HEADER_LENGTH]; 28 size_t taglen, offset, loop, hdrlen; 29 int ivlen; 30 unsigned char *staticiv; 31 unsigned char *seq; 32 int lenu, lenf; 33 SSL3_RECORD *rec = &recs[0]; 34 uint32_t alg_enc; 35 WPACKET wpkt; 36 37 if (n_recs != 1) { 38 /* Should not happen */ 39 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); 40 return 0; 41 } 42 43 if (sending) { 44 ctx = s->enc_write_ctx; 45 staticiv = s->write_iv; 46 seq = RECORD_LAYER_get_write_sequence(&s->rlayer); 47 } else { 48 ctx = s->enc_read_ctx; 49 staticiv = s->read_iv; 50 seq = RECORD_LAYER_get_read_sequence(&s->rlayer); 51 } 52 53 /* 54 * If we're sending an alert and ctx != NULL then we must be forcing 55 * plaintext alerts. If we're reading and ctx != NULL then we allow 56 * plaintext alerts at certain points in the handshake. If we've got this 57 * far then we have already validated that a plaintext alert is ok here. 58 */ 59 if (ctx == NULL || rec->type == SSL3_RT_ALERT) { 60 memmove(rec->data, rec->input, rec->length); 61 rec->input = rec->data; 62 return 1; 63 } 64 65 ivlen = EVP_CIPHER_CTX_get_iv_length(ctx); 66 if (ivlen < 0) { 67 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); 68 return 0; 69 } 70 71 if (s->early_data_state == SSL_EARLY_DATA_WRITING 72 || s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) { 73 if (s->session != NULL && s->session->ext.max_early_data > 0) { 74 alg_enc = s->session->cipher->algorithm_enc; 75 } else { 76 if (!ossl_assert(s->psksession != NULL 77 && s->psksession->ext.max_early_data > 0)) { 78 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); 79 return 0; 80 } 81 alg_enc = s->psksession->cipher->algorithm_enc; 82 } 83 } else { 84 /* 85 * To get here we must have selected a ciphersuite - otherwise ctx would 86 * be NULL 87 */ 88 if (!ossl_assert(s->s3.tmp.new_cipher != NULL)) { 89 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); 90 return 0; 91 } 92 alg_enc = s->s3.tmp.new_cipher->algorithm_enc; 93 } 94 95 if (alg_enc & SSL_AESCCM) { 96 if (alg_enc & (SSL_AES128CCM8 | SSL_AES256CCM8)) 97 taglen = EVP_CCM8_TLS_TAG_LEN; 98 else 99 taglen = EVP_CCM_TLS_TAG_LEN; 100 if (sending && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, 101 NULL) <= 0) { 102 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); 103 return 0; 104 } 105 } else if (alg_enc & SSL_AESGCM) { 106 taglen = EVP_GCM_TLS_TAG_LEN; 107 } else if (alg_enc & SSL_CHACHA20) { 108 taglen = EVP_CHACHAPOLY_TLS_TAG_LEN; 109 } else { 110 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); 111 return 0; 112 } 113 114 if (!sending) { 115 /* 116 * Take off tag. There must be at least one byte of content type as 117 * well as the tag 118 */ 119 if (rec->length < taglen + 1) 120 return 0; 121 rec->length -= taglen; 122 } 123 124 /* Set up IV */ 125 if (ivlen < SEQ_NUM_SIZE) { 126 /* Should not happen */ 127 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); 128 return 0; 129 } 130 offset = ivlen - SEQ_NUM_SIZE; 131 memcpy(iv, staticiv, offset); 132 for (loop = 0; loop < SEQ_NUM_SIZE; loop++) 133 iv[offset + loop] = staticiv[offset + loop] ^ seq[loop]; 134 135 /* Increment the sequence counter */ 136 for (loop = SEQ_NUM_SIZE; loop > 0; loop--) { 137 ++seq[loop - 1]; 138 if (seq[loop - 1] != 0) 139 break; 140 } 141 if (loop == 0) { 142 /* Sequence has wrapped */ 143 return 0; 144 } 145 146 if (EVP_CipherInit_ex(ctx, NULL, NULL, NULL, iv, sending) <= 0 147 || (!sending && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, 148 taglen, 149 rec->data + rec->length) <= 0)) { 150 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); 151 return 0; 152 } 153 154 /* Set up the AAD */ 155 if (!WPACKET_init_static_len(&wpkt, recheader, sizeof(recheader), 0) 156 || !WPACKET_put_bytes_u8(&wpkt, rec->type) 157 || !WPACKET_put_bytes_u16(&wpkt, rec->rec_version) 158 || !WPACKET_put_bytes_u16(&wpkt, rec->length + taglen) 159 || !WPACKET_get_total_written(&wpkt, &hdrlen) 160 || hdrlen != SSL3_RT_HEADER_LENGTH 161 || !WPACKET_finish(&wpkt)) { 162 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); 163 WPACKET_cleanup(&wpkt); 164 return 0; 165 } 166 167 /* 168 * For CCM we must explicitly set the total plaintext length before we add 169 * any AAD. 170 */ 171 if (((alg_enc & SSL_AESCCM) != 0 172 && EVP_CipherUpdate(ctx, NULL, &lenu, NULL, 173 (unsigned int)rec->length) <= 0) 174 || EVP_CipherUpdate(ctx, NULL, &lenu, recheader, 175 sizeof(recheader)) <= 0 176 || EVP_CipherUpdate(ctx, rec->data, &lenu, rec->input, 177 (unsigned int)rec->length) <= 0 178 || EVP_CipherFinal_ex(ctx, rec->data + lenu, &lenf) <= 0 179 || (size_t)(lenu + lenf) != rec->length) { 180 return 0; 181 } 182 if (sending) { 183 /* Add the tag */ 184 if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, 185 rec->data + rec->length) <= 0) { 186 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR); 187 return 0; 188 } 189 rec->length += taglen; 190 } 191 192 return 1; 193} 194