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/*
* Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "../ssl_local.h"
#include "record_local.h"
#include "internal/cryptlib.h"
/*-
* tls13_enc encrypts/decrypts |n_recs| in |recs|. Calls SSLfatal on internal
* error, but not otherwise. It is the responsibility of the caller to report
* a bad_record_mac.
*
* Returns:
* 0: On failure
* 1: if the record encryption/decryption was successful.
*/
int tls13_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending,
ossl_unused SSL_MAC_BUF *mac, ossl_unused size_t macsize)
{
EVP_CIPHER_CTX *ctx;
unsigned char iv[EVP_MAX_IV_LENGTH], recheader[SSL3_RT_HEADER_LENGTH];
size_t taglen, offset, loop, hdrlen;
int ivlen;
unsigned char *staticiv;
unsigned char *seq;
int lenu, lenf;
SSL3_RECORD *rec = &recs[0];
uint32_t alg_enc;
WPACKET wpkt;
if (n_recs != 1) {
/* Should not happen */
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
if (sending) {
ctx = s->enc_write_ctx;
staticiv = s->write_iv;
seq = RECORD_LAYER_get_write_sequence(&s->rlayer);
} else {
ctx = s->enc_read_ctx;
staticiv = s->read_iv;
seq = RECORD_LAYER_get_read_sequence(&s->rlayer);
}
/*
* If we're sending an alert and ctx != NULL then we must be forcing
* plaintext alerts. If we're reading and ctx != NULL then we allow
* plaintext alerts at certain points in the handshake. If we've got this
* far then we have already validated that a plaintext alert is ok here.
*/
if (ctx == NULL || rec->type == SSL3_RT_ALERT) {
memmove(rec->data, rec->input, rec->length);
rec->input = rec->data;
return 1;
}
ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
if (ivlen < 0) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
if (s->early_data_state == SSL_EARLY_DATA_WRITING
|| s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) {
if (s->session != NULL && s->session->ext.max_early_data > 0) {
alg_enc = s->session->cipher->algorithm_enc;
} else {
if (!ossl_assert(s->psksession != NULL
&& s->psksession->ext.max_early_data > 0)) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
alg_enc = s->psksession->cipher->algorithm_enc;
}
} else {
/*
* To get here we must have selected a ciphersuite - otherwise ctx would
* be NULL
*/
if (!ossl_assert(s->s3.tmp.new_cipher != NULL)) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
alg_enc = s->s3.tmp.new_cipher->algorithm_enc;
}
if (alg_enc & SSL_AESCCM) {
if (alg_enc & (SSL_AES128CCM8 | SSL_AES256CCM8))
taglen = EVP_CCM8_TLS_TAG_LEN;
else
taglen = EVP_CCM_TLS_TAG_LEN;
if (sending && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen,
NULL) <= 0) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
} else if (alg_enc & SSL_AESGCM) {
taglen = EVP_GCM_TLS_TAG_LEN;
} else if (alg_enc & SSL_CHACHA20) {
taglen = EVP_CHACHAPOLY_TLS_TAG_LEN;
} else {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
if (!sending) {
/*
* Take off tag. There must be at least one byte of content type as
* well as the tag
*/
if (rec->length < taglen + 1)
return 0;
rec->length -= taglen;
}
/* Set up IV */
if (ivlen < SEQ_NUM_SIZE) {
/* Should not happen */
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
offset = ivlen - SEQ_NUM_SIZE;
memcpy(iv, staticiv, offset);
for (loop = 0; loop < SEQ_NUM_SIZE; loop++)
iv[offset + loop] = staticiv[offset + loop] ^ seq[loop];
/* Increment the sequence counter */
for (loop = SEQ_NUM_SIZE; loop > 0; loop--) {
++seq[loop - 1];
if (seq[loop - 1] != 0)
break;
}
if (loop == 0) {
/* Sequence has wrapped */
return 0;
}
if (EVP_CipherInit_ex(ctx, NULL, NULL, NULL, iv, sending) <= 0
|| (!sending && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG,
taglen,
rec->data + rec->length) <= 0)) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
/* Set up the AAD */
if (!WPACKET_init_static_len(&wpkt, recheader, sizeof(recheader), 0)
|| !WPACKET_put_bytes_u8(&wpkt, rec->type)
|| !WPACKET_put_bytes_u16(&wpkt, rec->rec_version)
|| !WPACKET_put_bytes_u16(&wpkt, rec->length + taglen)
|| !WPACKET_get_total_written(&wpkt, &hdrlen)
|| hdrlen != SSL3_RT_HEADER_LENGTH
|| !WPACKET_finish(&wpkt)) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
WPACKET_cleanup(&wpkt);
return 0;
}
/*
* For CCM we must explicitly set the total plaintext length before we add
* any AAD.
*/
if (((alg_enc & SSL_AESCCM) != 0
&& EVP_CipherUpdate(ctx, NULL, &lenu, NULL,
(unsigned int)rec->length) <= 0)
|| EVP_CipherUpdate(ctx, NULL, &lenu, recheader,
sizeof(recheader)) <= 0
|| EVP_CipherUpdate(ctx, rec->data, &lenu, rec->input,
(unsigned int)rec->length) <= 0
|| EVP_CipherFinal_ex(ctx, rec->data + lenu, &lenf) <= 0
|| (size_t)(lenu + lenf) != rec->length) {
return 0;
}
if (sending) {
/* Add the tag */
if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen,
rec->data + rec->length) <= 0) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
return 0;
}
rec->length += taglen;
}
return 1;
}
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