pineapple-src/externals/libressl/ssl/tls12_record_layer.c
2020-12-28 15:15:37 +00:00

542 lines
13 KiB
C
Executable file

/* $OpenBSD: tls12_record_layer.c,v 1.4 2020/09/16 17:15:01 jsing Exp $ */
/*
* Copyright (c) 2020 Joel Sing <jsing@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <stdlib.h>
#include <openssl/evp.h>
#include "ssl_locl.h"
struct tls12_record_layer {
uint16_t version;
int dtls;
uint16_t read_epoch;
uint16_t write_epoch;
int read_stream_mac;
int write_stream_mac;
/*
* XXX - for now these are just pointers to externally managed
* structs/memory. These should eventually be owned by the record layer.
*/
SSL_AEAD_CTX *read_aead_ctx;
SSL_AEAD_CTX *write_aead_ctx;
EVP_CIPHER_CTX *read_cipher_ctx;
EVP_MD_CTX *read_hash_ctx;
EVP_CIPHER_CTX *write_cipher_ctx;
EVP_MD_CTX *write_hash_ctx;
uint8_t *read_seq_num;
uint8_t *write_seq_num;
};
struct tls12_record_layer *
tls12_record_layer_new(void)
{
struct tls12_record_layer *rl;
if ((rl = calloc(1, sizeof(struct tls12_record_layer))) == NULL)
return NULL;
return rl;
}
void
tls12_record_layer_free(struct tls12_record_layer *rl)
{
freezero(rl, sizeof(struct tls12_record_layer));
}
void
tls12_record_layer_set_version(struct tls12_record_layer *rl, uint16_t version)
{
rl->version = version;
rl->dtls = (version == DTLS1_VERSION);
}
void
tls12_record_layer_set_read_epoch(struct tls12_record_layer *rl, uint16_t epoch)
{
rl->read_epoch = epoch;
}
void
tls12_record_layer_set_write_epoch(struct tls12_record_layer *rl, uint16_t epoch)
{
rl->write_epoch = epoch;
}
static void
tls12_record_layer_set_read_state(struct tls12_record_layer *rl,
SSL_AEAD_CTX *aead_ctx, EVP_CIPHER_CTX *cipher_ctx, EVP_MD_CTX *hash_ctx,
int stream_mac)
{
rl->read_aead_ctx = aead_ctx;
rl->read_cipher_ctx = cipher_ctx;
rl->read_hash_ctx = hash_ctx;
rl->read_stream_mac = stream_mac;
}
static void
tls12_record_layer_set_write_state(struct tls12_record_layer *rl,
SSL_AEAD_CTX *aead_ctx, EVP_CIPHER_CTX *cipher_ctx, EVP_MD_CTX *hash_ctx,
int stream_mac)
{
rl->write_aead_ctx = aead_ctx;
rl->write_cipher_ctx = cipher_ctx;
rl->write_hash_ctx = hash_ctx;
rl->write_stream_mac = stream_mac;
}
void
tls12_record_layer_clear_read_state(struct tls12_record_layer *rl)
{
tls12_record_layer_set_read_state(rl, NULL, NULL, NULL, 0);
rl->read_seq_num = NULL;
}
void
tls12_record_layer_clear_write_state(struct tls12_record_layer *rl)
{
tls12_record_layer_set_write_state(rl, NULL, NULL, NULL, 0);
rl->write_seq_num = NULL;
}
void
tls12_record_layer_set_read_seq_num(struct tls12_record_layer *rl,
uint8_t *seq_num)
{
rl->read_seq_num = seq_num;
}
void
tls12_record_layer_set_write_seq_num(struct tls12_record_layer *rl,
uint8_t *seq_num)
{
rl->write_seq_num = seq_num;
}
int
tls12_record_layer_set_read_aead(struct tls12_record_layer *rl,
SSL_AEAD_CTX *aead_ctx)
{
tls12_record_layer_set_read_state(rl, aead_ctx, NULL, NULL, 0);
return 1;
}
int
tls12_record_layer_set_write_aead(struct tls12_record_layer *rl,
SSL_AEAD_CTX *aead_ctx)
{
tls12_record_layer_set_write_state(rl, aead_ctx, NULL, NULL, 0);
return 1;
}
int
tls12_record_layer_set_read_cipher_hash(struct tls12_record_layer *rl,
EVP_CIPHER_CTX *cipher_ctx, EVP_MD_CTX *hash_ctx, int stream_mac)
{
tls12_record_layer_set_read_state(rl, NULL, cipher_ctx, hash_ctx,
stream_mac);
return 1;
}
int
tls12_record_layer_set_write_cipher_hash(struct tls12_record_layer *rl,
EVP_CIPHER_CTX *cipher_ctx, EVP_MD_CTX *hash_ctx, int stream_mac)
{
tls12_record_layer_set_write_state(rl, NULL, cipher_ctx, hash_ctx,
stream_mac);
return 1;
}
static int
tls12_record_layer_build_seq_num(struct tls12_record_layer *rl, CBB *cbb,
uint16_t epoch, uint8_t *seq_num, size_t seq_num_len)
{
CBS seq;
CBS_init(&seq, seq_num, seq_num_len);
if (rl->dtls) {
if (!CBB_add_u16(cbb, epoch))
return 0;
if (!CBS_skip(&seq, 2))
return 0;
}
return CBB_add_bytes(cbb, CBS_data(&seq), CBS_len(&seq));
}
static int
tls12_record_layer_pseudo_header(struct tls12_record_layer *rl,
uint8_t content_type, uint16_t record_len, uint16_t epoch, uint8_t *seq_num,
size_t seq_num_len, uint8_t **out, size_t *out_len)
{
CBB cbb;
*out = NULL;
*out_len = 0;
/* Build the pseudo-header used for MAC/AEAD. */
if (!CBB_init(&cbb, 13))
goto err;
if (!tls12_record_layer_build_seq_num(rl, &cbb, epoch,
seq_num, seq_num_len))
goto err;
if (!CBB_add_u8(&cbb, content_type))
goto err;
if (!CBB_add_u16(&cbb, rl->version))
goto err;
if (!CBB_add_u16(&cbb, record_len))
goto err;
if (!CBB_finish(&cbb, out, out_len))
goto err;
return 1;
err:
CBB_cleanup(&cbb);
return 0;
}
static int
tls12_record_layer_mac(struct tls12_record_layer *rl, CBB *cbb,
EVP_MD_CTX *hash_ctx, int stream_mac, uint16_t epoch, uint8_t *seq_num,
size_t seq_num_len, uint8_t content_type, const uint8_t *content,
size_t content_len, size_t *out_len)
{
EVP_MD_CTX *mac_ctx = NULL;
uint8_t *header = NULL;
size_t header_len;
size_t mac_len;
uint8_t *mac;
int ret = 0;
if ((mac_ctx = EVP_MD_CTX_new()) == NULL)
goto err;
if (!EVP_MD_CTX_copy(mac_ctx, hash_ctx))
goto err;
if (!tls12_record_layer_pseudo_header(rl, content_type, content_len,
epoch, seq_num, seq_num_len, &header, &header_len))
goto err;
if (EVP_DigestSignUpdate(mac_ctx, header, header_len) <= 0)
goto err;
if (EVP_DigestSignUpdate(mac_ctx, content, content_len) <= 0)
goto err;
if (EVP_DigestSignFinal(mac_ctx, NULL, &mac_len) <= 0)
goto err;
if (!CBB_add_space(cbb, &mac, mac_len))
goto err;
if (EVP_DigestSignFinal(mac_ctx, mac, &mac_len) <= 0)
goto err;
if (stream_mac) {
if (!EVP_MD_CTX_copy(hash_ctx, mac_ctx))
goto err;
}
*out_len = mac_len;
ret = 1;
err:
EVP_MD_CTX_free(mac_ctx);
free(header);
return ret;
}
static int
tls12_record_layer_write_mac(struct tls12_record_layer *rl, CBB *cbb,
uint8_t content_type, const uint8_t *content, size_t content_len,
size_t *out_len)
{
return tls12_record_layer_mac(rl, cbb, rl->write_hash_ctx,
rl->write_stream_mac, rl->write_epoch, rl->write_seq_num,
SSL3_SEQUENCE_SIZE, content_type, content, content_len, out_len);
}
static int
tls12_record_layer_aead_concat_nonce(struct tls12_record_layer *rl,
const SSL_AEAD_CTX *aead, uint8_t *seq_num, uint8_t **out, size_t *out_len)
{
CBB cbb;
if (aead->variable_nonce_len > SSL3_SEQUENCE_SIZE)
return 0;
/* Fixed nonce and variable nonce (sequence number) are concatenated. */
if (!CBB_init(&cbb, 16))
goto err;
if (!CBB_add_bytes(&cbb, aead->fixed_nonce,
aead->fixed_nonce_len))
goto err;
if (!CBB_add_bytes(&cbb, seq_num, aead->variable_nonce_len))
goto err;
if (!CBB_finish(&cbb, out, out_len))
goto err;
return 1;
err:
CBB_cleanup(&cbb);
return 0;
}
static int
tls12_record_layer_aead_xored_nonce(struct tls12_record_layer *rl,
const SSL_AEAD_CTX *aead, uint8_t *seq_num, uint8_t **out, size_t *out_len)
{
uint8_t *nonce = NULL;
size_t nonce_len = 0;
uint8_t *pad;
CBB cbb;
int i;
if (aead->variable_nonce_len > SSL3_SEQUENCE_SIZE)
return 0;
if (aead->fixed_nonce_len < aead->variable_nonce_len)
return 0;
/*
* Variable nonce (sequence number) is right padded, before the fixed
* nonce is XOR'd in.
*/
if (!CBB_init(&cbb, 16))
goto err;
if (!CBB_add_space(&cbb, &pad,
aead->fixed_nonce_len - aead->variable_nonce_len))
goto err;
if (!CBB_add_bytes(&cbb, seq_num, aead->variable_nonce_len))
goto err;
if (!CBB_finish(&cbb, &nonce, &nonce_len))
goto err;
for (i = 0; i < aead->fixed_nonce_len; i++)
nonce[i] ^= aead->fixed_nonce[i];
*out = nonce;
*out_len = nonce_len;
return 1;
err:
CBB_cleanup(&cbb);
freezero(nonce, nonce_len);
return 0;
}
static int
tls12_record_layer_seal_record_plaintext(struct tls12_record_layer *rl,
uint8_t content_type, const uint8_t *content, size_t content_len, CBB *out)
{
if (rl->write_aead_ctx != NULL || rl->write_cipher_ctx != NULL)
return 0;
return CBB_add_bytes(out, content, content_len);
}
static int
tls12_record_layer_seal_record_protected_aead(struct tls12_record_layer *rl,
uint8_t content_type, const uint8_t *content, size_t content_len, CBB *out)
{
const SSL_AEAD_CTX *aead = rl->write_aead_ctx;
uint8_t *header = NULL, *nonce = NULL;
size_t header_len = 0, nonce_len = 0;
size_t enc_record_len, out_len;
uint16_t epoch = 0;
uint8_t *enc_data;
int ret = 0;
/* XXX - move to nonce allocated in record layer, matching TLSv1.3 */
if (aead->xor_fixed_nonce) {
if (!tls12_record_layer_aead_xored_nonce(rl, aead,
rl->write_seq_num, &nonce, &nonce_len))
goto err;
} else {
if (!tls12_record_layer_aead_concat_nonce(rl, aead,
rl->write_seq_num, &nonce, &nonce_len))
goto err;
}
if (aead->variable_nonce_in_record) {
/* XXX - length check? */
if (!CBB_add_bytes(out, rl->write_seq_num, aead->variable_nonce_len))
goto err;
}
if (!tls12_record_layer_pseudo_header(rl, content_type, content_len,
epoch, rl->write_seq_num, SSL3_SEQUENCE_SIZE, &header, &header_len))
goto err;
/* XXX EVP_AEAD_max_tag_len vs EVP_AEAD_CTX_tag_len. */
enc_record_len = content_len + aead->tag_len;
if (enc_record_len > SSL3_RT_MAX_ENCRYPTED_LENGTH)
goto err;
if (!CBB_add_space(out, &enc_data, enc_record_len))
goto err;
if (!EVP_AEAD_CTX_seal(&aead->ctx, enc_data, &out_len, enc_record_len,
nonce, nonce_len, content, content_len, header, header_len))
goto err;
if (out_len != enc_record_len)
goto err;
ret = 1;
err:
freezero(header, header_len);
freezero(nonce, nonce_len);
return ret;
}
static int
tls12_record_layer_seal_record_protected_cipher(struct tls12_record_layer *rl,
uint8_t content_type, const uint8_t *content, size_t content_len, CBB *out)
{
EVP_CIPHER_CTX *enc = rl->write_cipher_ctx;
size_t mac_len, pad_len;
int block_size, eiv_len;
uint8_t *enc_data, *eiv, *pad, pad_val;
uint8_t *plain = NULL;
size_t plain_len = 0;
int ret = 0;
CBB cbb;
if (!CBB_init(&cbb, SSL3_RT_MAX_PLAIN_LENGTH))
goto err;
/* Add explicit IV if necessary. */
eiv_len = 0;
if (rl->version != TLS1_VERSION &&
EVP_CIPHER_CTX_mode(enc) == EVP_CIPH_CBC_MODE)
eiv_len = EVP_CIPHER_CTX_iv_length(enc);
if (eiv_len < 0 || eiv_len > EVP_MAX_IV_LENGTH)
goto err;
if (eiv_len > 0) {
if (!CBB_add_space(&cbb, &eiv, eiv_len))
goto err;
arc4random_buf(eiv, eiv_len);
}
if (!CBB_add_bytes(&cbb, content, content_len))
goto err;
mac_len = 0;
if (rl->write_hash_ctx != NULL) {
if (!tls12_record_layer_write_mac(rl, &cbb, content_type,
content, content_len, &mac_len))
goto err;
}
plain_len = (size_t)eiv_len + content_len + mac_len;
/* Add padding to block size, if necessary. */
block_size = EVP_CIPHER_CTX_block_size(enc);
if (block_size < 0 || block_size > EVP_MAX_BLOCK_LENGTH)
goto err;
if (block_size > 1) {
pad_len = block_size - (plain_len % block_size);
pad_val = pad_len - 1;
if (pad_len > 255)
goto err;
if (!CBB_add_space(&cbb, &pad, pad_len))
goto err;
memset(pad, pad_val, pad_len);
}
if (!CBB_finish(&cbb, &plain, &plain_len))
goto err;
if (plain_len % block_size != 0)
goto err;
if (plain_len > SSL3_RT_MAX_ENCRYPTED_LENGTH)
goto err;
if (!CBB_add_space(out, &enc_data, plain_len))
goto err;
if (!EVP_Cipher(enc, enc_data, plain, plain_len))
goto err;
ret = 1;
err:
CBB_cleanup(&cbb);
freezero(plain, plain_len);
return ret;
}
int
tls12_record_layer_seal_record(struct tls12_record_layer *rl,
uint8_t content_type, const uint8_t *content, size_t content_len, CBB *cbb)
{
CBB fragment;
if (!CBB_add_u8(cbb, content_type))
return 0;
if (!CBB_add_u16(cbb, rl->version))
return 0;
if (rl->dtls) {
if (!tls12_record_layer_build_seq_num(rl, cbb,
rl->write_epoch, rl->write_seq_num,
SSL3_SEQUENCE_SIZE))
return 0;
}
if (!CBB_add_u16_length_prefixed(cbb, &fragment))
return 0;
if (rl->write_aead_ctx != NULL) {
if (!tls12_record_layer_seal_record_protected_aead(rl,
content_type, content, content_len, &fragment))
return 0;
} else if (rl->write_cipher_ctx != NULL) {
if (!tls12_record_layer_seal_record_protected_cipher(rl,
content_type, content, content_len, &fragment))
return 0;
} else {
if (!tls12_record_layer_seal_record_plaintext(rl,
content_type, content, content_len, &fragment))
return 0;
}
if (!CBB_flush(cbb))
return 0;
tls1_record_sequence_increment(rl->write_seq_num);
return 1;
}