1 /*
2 * Copyright 2016-2021 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 <assert.h>
11 #include "../ssl_local.h"
12 #include "record_local.h"
13 #include "internal/cryptlib.h"
14
15 /*-
16 * tls13_enc encrypts/decrypts |n_recs| in |recs|. Calls SSLfatal on internal
17 * error, but not otherwise. It is the responsibility of the caller to report
18 * a bad_record_mac.
19 *
20 * Returns:
21 * 0: On failure
22 * 1: if the record encryption/decryption was successful.
23 */
tls13_enc(SSL_CONNECTION * s,SSL3_RECORD * recs,size_t n_recs,int sending,ossl_unused SSL_MAC_BUF * mac,ossl_unused size_t macsize)24 int tls13_enc(SSL_CONNECTION *s, SSL3_RECORD *recs, size_t n_recs, int sending,
25 ossl_unused SSL_MAC_BUF *mac, ossl_unused size_t macsize)
26 {
27 EVP_CIPHER_CTX *ctx;
28 unsigned char iv[EVP_MAX_IV_LENGTH], recheader[SSL3_RT_HEADER_LENGTH];
29 size_t taglen, offset, loop, hdrlen;
30 int ivlen;
31 unsigned char *staticiv;
32 unsigned char *seq;
33 int lenu, lenf;
34 SSL3_RECORD *rec = &recs[0];
35 uint32_t alg_enc;
36 WPACKET wpkt;
37
38 if (n_recs != 1) {
39 /* Should not happen */
40 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
41 return 0;
42 }
43
44 assert(sending);
45 ctx = s->enc_write_ctx;
46 staticiv = s->write_iv;
47 seq = RECORD_LAYER_get_write_sequence(&s->rlayer);
48
49 /*
50 * If we're sending an alert and ctx != NULL then we must be forcing
51 * plaintext alerts. If we're reading and ctx != NULL then we allow
52 * plaintext alerts at certain points in the handshake. If we've got this
53 * far then we have already validated that a plaintext alert is ok here.
54 */
55 if (ctx == NULL || rec->type == SSL3_RT_ALERT) {
56 memmove(rec->data, rec->input, rec->length);
57 rec->input = rec->data;
58 return 1;
59 }
60
61 ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
62 if (ivlen < 0) {
63 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
64 return 0;
65 }
66
67 if (s->early_data_state == SSL_EARLY_DATA_WRITING
68 || s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) {
69 if (s->session != NULL && s->session->ext.max_early_data > 0) {
70 alg_enc = s->session->cipher->algorithm_enc;
71 } else {
72 if (!ossl_assert(s->psksession != NULL
73 && s->psksession->ext.max_early_data > 0)) {
74 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
75 return 0;
76 }
77 alg_enc = s->psksession->cipher->algorithm_enc;
78 }
79 } else {
80 /*
81 * To get here we must have selected a ciphersuite - otherwise ctx would
82 * be NULL
83 */
84 if (!ossl_assert(s->s3.tmp.new_cipher != NULL)) {
85 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
86 return 0;
87 }
88 alg_enc = s->s3.tmp.new_cipher->algorithm_enc;
89 }
90
91 if (alg_enc & SSL_AESCCM) {
92 if (alg_enc & (SSL_AES128CCM8 | SSL_AES256CCM8))
93 taglen = EVP_CCM8_TLS_TAG_LEN;
94 else
95 taglen = EVP_CCM_TLS_TAG_LEN;
96 if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, NULL) <= 0) {
97 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
98 return 0;
99 }
100 } else if (alg_enc & SSL_AESGCM) {
101 taglen = EVP_GCM_TLS_TAG_LEN;
102 } else if (alg_enc & SSL_CHACHA20) {
103 taglen = EVP_CHACHAPOLY_TLS_TAG_LEN;
104 } else {
105 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
106 return 0;
107 }
108
109 /* Set up IV */
110 if (ivlen < SEQ_NUM_SIZE) {
111 /* Should not happen */
112 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
113 return 0;
114 }
115 offset = ivlen - SEQ_NUM_SIZE;
116 memcpy(iv, staticiv, offset);
117 for (loop = 0; loop < SEQ_NUM_SIZE; loop++)
118 iv[offset + loop] = staticiv[offset + loop] ^ seq[loop];
119
120 /* Increment the sequence counter */
121 for (loop = SEQ_NUM_SIZE; loop > 0; loop--) {
122 ++seq[loop - 1];
123 if (seq[loop - 1] != 0)
124 break;
125 }
126 if (loop == 0) {
127 /* Sequence has wrapped */
128 return 0;
129 }
130
131 if (EVP_CipherInit_ex(ctx, NULL, NULL, NULL, iv, sending) <= 0) {
132 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
133 return 0;
134 }
135
136 /* Set up the AAD */
137 if (!WPACKET_init_static_len(&wpkt, recheader, sizeof(recheader), 0)
138 || !WPACKET_put_bytes_u8(&wpkt, rec->type)
139 || !WPACKET_put_bytes_u16(&wpkt, rec->rec_version)
140 || !WPACKET_put_bytes_u16(&wpkt, rec->length + taglen)
141 || !WPACKET_get_total_written(&wpkt, &hdrlen)
142 || hdrlen != SSL3_RT_HEADER_LENGTH
143 || !WPACKET_finish(&wpkt)) {
144 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
145 WPACKET_cleanup(&wpkt);
146 return 0;
147 }
148
149 /*
150 * For CCM we must explicitly set the total plaintext length before we add
151 * any AAD.
152 */
153 if (((alg_enc & SSL_AESCCM) != 0
154 && EVP_CipherUpdate(ctx, NULL, &lenu, NULL,
155 (unsigned int)rec->length) <= 0)
156 || EVP_CipherUpdate(ctx, NULL, &lenu, recheader,
157 sizeof(recheader)) <= 0
158 || EVP_CipherUpdate(ctx, rec->data, &lenu, rec->input,
159 (unsigned int)rec->length) <= 0
160 || EVP_CipherFinal_ex(ctx, rec->data + lenu, &lenf) <= 0
161 || (size_t)(lenu + lenf) != rec->length) {
162 return 0;
163 }
164
165 /* Add the tag */
166 if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen,
167 rec->data + rec->length) <= 0) {
168 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
169 return 0;
170 }
171 rec->length += taglen;
172
173 return 1;
174 }
175