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 */
tls13_enc(SSL * s,SSL3_RECORD * recs,size_t n_recs,int sending,ossl_unused SSL_MAC_BUF * mac,ossl_unused size_t macsize)23 int 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