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/*
* Copyright (c) 2009 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is originally derived from software contributed to
* The NetBSD Foundation by Alistair Crooks (agc@netbsd.org), and
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 2005-2008 Nominet UK (www.nic.uk)
* All rights reserved.
* Contributors: Ben Laurie, Rachel Willmer. The Contributors have asserted
* their moral rights under the UK Copyright Design and Patents Act 1988 to
* be recorded as the authors of this copyright work.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License.
*
* You may obtain a copy of the License at
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "crypto.h"
#include "config.h"
#include "defaults.h"
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <botan/ffi.h>
#include <botan/build.h>
#include "utils.h"
static const char *
pgp_sa_to_botan_string(int alg, bool silent = false)
{
switch (alg) {
#if defined(BOTAN_HAS_IDEA) && defined(ENABLE_IDEA)
case PGP_SA_IDEA:
return "IDEA";
#endif
#if defined(BOTAN_HAS_DES)
case PGP_SA_TRIPLEDES:
return "TripleDES";
#endif
#if defined(BOTAN_HAS_CAST) && defined(ENABLE_CAST5)
case PGP_SA_CAST5:
return "CAST-128";
#endif
#if defined(BOTAN_HAS_BLOWFISH) && defined(ENABLE_BLOWFISH)
case PGP_SA_BLOWFISH:
return "Blowfish";
#endif
#if defined(BOTAN_HAS_AES)
case PGP_SA_AES_128:
return "AES-128";
case PGP_SA_AES_192:
return "AES-192";
case PGP_SA_AES_256:
return "AES-256";
#endif
#if defined(BOTAN_HAS_SM4) && defined(ENABLE_SM2)
case PGP_SA_SM4:
return "SM4";
#endif
#if defined(BOTAN_HAS_TWOFISH) && defined(ENABLE_TWOFISH)
case PGP_SA_TWOFISH:
return "Twofish";
#endif
#if defined(BOTAN_HAS_CAMELLIA)
case PGP_SA_CAMELLIA_128:
return "Camellia-128";
case PGP_SA_CAMELLIA_192:
return "Camellia-192";
case PGP_SA_CAMELLIA_256:
return "Camellia-256";
#endif
default:
if (!silent) {
RNP_LOG("Unsupported symmetric algorithm %d", alg);
}
return NULL;
}
}
#if defined(ENABLE_AEAD)
static bool
pgp_aead_to_botan_string(pgp_symm_alg_t ealg, pgp_aead_alg_t aalg, char *buf, size_t len)
{
const char *ealg_name = pgp_sa_to_botan_string(ealg);
size_t ealg_len;
if (!ealg_name) {
return false;
}
ealg_len = strlen(ealg_name);
if (len < ealg_len + 5) {
RNP_LOG("buffer too small");
return false;
}
switch (aalg) {
case PGP_AEAD_EAX:
memcpy(buf, ealg_name, ealg_len);
strncpy(buf + ealg_len, "/EAX", len - ealg_len);
break;
case PGP_AEAD_OCB:
memcpy(buf, ealg_name, ealg_len);
strncpy(buf + ealg_len, "/OCB", len - ealg_len);
break;
default:
RNP_LOG("unsupported AEAD alg %d", (int) aalg);
return false;
}
return true;
}
#endif
bool
pgp_cipher_cfb_start(pgp_crypt_t * crypt,
pgp_symm_alg_t alg,
const uint8_t *key,
const uint8_t *iv)
{
memset(crypt, 0x0, sizeof(*crypt));
const char *cipher_name = pgp_sa_to_botan_string(alg);
if (!cipher_name) {
return false;
}
crypt->alg = alg;
crypt->blocksize = pgp_block_size(alg);
// This shouldn't happen if pgp_sa_to_botan_string returned a ptr
if (botan_block_cipher_init(&(crypt->cfb.obj), cipher_name) != 0) {
RNP_LOG("Block cipher '%s' not available", cipher_name);
return false;
}
const size_t keysize = pgp_key_size(alg);
if (botan_block_cipher_set_key(crypt->cfb.obj, key, keysize) != 0) {
RNP_LOG("Failure setting key on block cipher object");
return false;
}
if (iv != NULL) {
// Otherwise left as all zeros via memset at start of function
memcpy(crypt->cfb.iv, iv, crypt->blocksize);
}
crypt->cfb.remaining = 0;
return true;
}
void
pgp_cipher_cfb_resync(pgp_crypt_t *crypt, const uint8_t *buf)
{
/* iv will be encrypted in the upcoming call to encrypt/decrypt */
memcpy(crypt->cfb.iv, buf, crypt->blocksize);
crypt->cfb.remaining = 0;
}
int
pgp_cipher_cfb_finish(pgp_crypt_t *crypt)
{
if (!crypt) {
return 0;
}
if (crypt->cfb.obj) {
botan_block_cipher_destroy(crypt->cfb.obj);
crypt->cfb.obj = NULL;
}
botan_scrub_mem((uint8_t *) crypt, sizeof(*crypt));
return 0;
}
/* we rely on fact that in and out could be the same */
int
pgp_cipher_cfb_encrypt(pgp_crypt_t *crypt, uint8_t *out, const uint8_t *in, size_t bytes)
{
uint64_t *in64;
uint64_t buf64[512]; // 4KB - page size
uint64_t iv64[2];
size_t blocks, blockb;
size_t blsize = crypt->blocksize;
/* encrypting till the block boundary */
while (bytes && crypt->cfb.remaining) {
*out = *in++ ^ crypt->cfb.iv[blsize - crypt->cfb.remaining];
crypt->cfb.iv[blsize - crypt->cfb.remaining] = *out++;
crypt->cfb.remaining--;
bytes--;
}
if (!bytes) {
return 0;
}
/* encrypting full blocks */
if (bytes > blsize) {
memcpy(iv64, crypt->cfb.iv, blsize);
while ((blocks = bytes & ~(blsize - 1)) > 0) {
if (blocks > sizeof(buf64)) {
blocks = sizeof(buf64);
}
bytes -= blocks;
blockb = blocks;
memcpy(buf64, in, blockb);
in64 = buf64;
if (blsize == 16) {
blocks >>= 4;
while (blocks--) {
botan_block_cipher_encrypt_blocks(
crypt->cfb.obj, (uint8_t *) iv64, (uint8_t *) iv64, 1);
*in64 ^= iv64[0];
iv64[0] = *in64++;
*in64 ^= iv64[1];
iv64[1] = *in64++;
}
} else {
blocks >>= 3;
while (blocks--) {
botan_block_cipher_encrypt_blocks(
crypt->cfb.obj, (uint8_t *) iv64, (uint8_t *) iv64, 1);
*in64 ^= iv64[0];
iv64[0] = *in64++;
}
}
memcpy(out, buf64, blockb);
out += blockb;
in += blockb;
}
memcpy(crypt->cfb.iv, iv64, blsize);
}
if (!bytes) {
return 0;
}
botan_block_cipher_encrypt_blocks(crypt->cfb.obj, crypt->cfb.iv, crypt->cfb.iv, 1);
crypt->cfb.remaining = blsize;
/* encrypting tail */
while (bytes) {
*out = *in++ ^ crypt->cfb.iv[blsize - crypt->cfb.remaining];
crypt->cfb.iv[blsize - crypt->cfb.remaining] = *out++;
crypt->cfb.remaining--;
bytes--;
}
return 0;
}
/* we rely on fact that in and out could be the same */
int
pgp_cipher_cfb_decrypt(pgp_crypt_t *crypt, uint8_t *out, const uint8_t *in, size_t bytes)
{
/* for better code readability */
uint64_t *out64, *in64;
uint64_t inbuf64[512]; // 4KB - page size
uint64_t outbuf64[512];
uint64_t iv64[2];
size_t blocks, blockb;
size_t blsize = crypt->blocksize;
/* decrypting till the block boundary */
while (bytes && crypt->cfb.remaining) {
uint8_t c = *in++;
*out++ = c ^ crypt->cfb.iv[blsize - crypt->cfb.remaining];
crypt->cfb.iv[blsize - crypt->cfb.remaining] = c;
crypt->cfb.remaining--;
bytes--;
}
if (!bytes) {
return 0;
}
/* decrypting full blocks */
if (bytes > blsize) {
memcpy(iv64, crypt->cfb.iv, blsize);
while ((blocks = bytes & ~(blsize - 1)) > 0) {
if (blocks > sizeof(inbuf64)) {
blocks = sizeof(inbuf64);
}
bytes -= blocks;
blockb = blocks;
memcpy(inbuf64, in, blockb);
out64 = outbuf64;
in64 = inbuf64;
if (blsize == 16) {
blocks >>= 4;
while (blocks--) {
botan_block_cipher_encrypt_blocks(
crypt->cfb.obj, (uint8_t *) iv64, (uint8_t *) iv64, 1);
*out64++ = *in64 ^ iv64[0];
iv64[0] = *in64++;
*out64++ = *in64 ^ iv64[1];
iv64[1] = *in64++;
}
} else {
blocks >>= 3;
while (blocks--) {
botan_block_cipher_encrypt_blocks(
crypt->cfb.obj, (uint8_t *) iv64, (uint8_t *) iv64, 1);
*out64++ = *in64 ^ iv64[0];
iv64[0] = *in64++;
}
}
memcpy(out, outbuf64, blockb);
out += blockb;
in += blockb;
}
memcpy(crypt->cfb.iv, iv64, blsize);
}
if (!bytes) {
return 0;
}
botan_block_cipher_encrypt_blocks(crypt->cfb.obj, crypt->cfb.iv, crypt->cfb.iv, 1);
crypt->cfb.remaining = blsize;
/* decrypting tail */
while (bytes) {
uint8_t c = *in++;
*out++ = c ^ crypt->cfb.iv[blsize - crypt->cfb.remaining];
crypt->cfb.iv[blsize - crypt->cfb.remaining] = c;
crypt->cfb.remaining--;
bytes--;
}
return 0;
}
size_t
pgp_cipher_block_size(pgp_crypt_t *crypt)
{
return crypt->blocksize;
}
unsigned
pgp_block_size(pgp_symm_alg_t alg)
{
switch (alg) {
case PGP_SA_IDEA:
case PGP_SA_TRIPLEDES:
case PGP_SA_CAST5:
case PGP_SA_BLOWFISH:
return 8;
case PGP_SA_AES_128:
case PGP_SA_AES_192:
case PGP_SA_AES_256:
case PGP_SA_TWOFISH:
case PGP_SA_CAMELLIA_128:
case PGP_SA_CAMELLIA_192:
case PGP_SA_CAMELLIA_256:
case PGP_SA_SM4:
return 16;
default:
return 0;
}
}
unsigned
pgp_key_size(pgp_symm_alg_t alg)
{
/* Update MAX_SYMM_KEY_SIZE after adding algorithm
* with bigger key size.
*/
static_assert(32 == MAX_SYMM_KEY_SIZE, "MAX_SYMM_KEY_SIZE must be updated");
switch (alg) {
case PGP_SA_IDEA:
case PGP_SA_CAST5:
case PGP_SA_BLOWFISH:
case PGP_SA_AES_128:
case PGP_SA_CAMELLIA_128:
case PGP_SA_SM4:
return 16;
case PGP_SA_TRIPLEDES:
case PGP_SA_AES_192:
case PGP_SA_CAMELLIA_192:
return 24;
case PGP_SA_TWOFISH:
case PGP_SA_AES_256:
case PGP_SA_CAMELLIA_256:
return 32;
default:
return 0;
}
}
bool
pgp_is_sa_supported(int alg, bool silent)
{
return pgp_sa_to_botan_string(alg, silent);
}
#if defined(ENABLE_AEAD)
bool
pgp_cipher_aead_init(pgp_crypt_t * crypt,
pgp_symm_alg_t ealg,
pgp_aead_alg_t aalg,
const uint8_t *key,
bool decrypt)
{
char cipher_name[32];
uint32_t flags;
memset(crypt, 0x0, sizeof(*crypt));
if (!pgp_aead_to_botan_string(ealg, aalg, cipher_name, sizeof(cipher_name))) {
return false;
}
crypt->alg = ealg;
crypt->blocksize = pgp_block_size(ealg);
crypt->aead.alg = aalg;
crypt->aead.decrypt = decrypt;
crypt->aead.taglen = PGP_AEAD_EAX_OCB_TAG_LEN; /* it's the same for EAX and OCB */
flags = decrypt ? BOTAN_CIPHER_INIT_FLAG_DECRYPT : BOTAN_CIPHER_INIT_FLAG_ENCRYPT;
if (botan_cipher_init(&(crypt->aead.obj), cipher_name, flags)) {
RNP_LOG("cipher %s is not available", cipher_name);
return false;
}
if (botan_cipher_set_key(crypt->aead.obj, key, (size_t) pgp_key_size(ealg))) {
RNP_LOG("failed to set key");
return false;
}
if (botan_cipher_get_update_granularity(crypt->aead.obj, &crypt->aead.granularity)) {
RNP_LOG("failed to get update granularity");
return false;
}
return true;
}
size_t
pgp_cipher_aead_granularity(pgp_crypt_t *crypt)
{
return crypt->aead.granularity;
}
#endif
size_t
pgp_cipher_aead_nonce_len(pgp_aead_alg_t aalg)
{
switch (aalg) {
case PGP_AEAD_EAX:
return PGP_AEAD_EAX_NONCE_LEN;
case PGP_AEAD_OCB:
return PGP_AEAD_OCB_NONCE_LEN;
default:
return 0;
}
}
size_t
pgp_cipher_aead_tag_len(pgp_aead_alg_t aalg)
{
switch (aalg) {
case PGP_AEAD_EAX:
case PGP_AEAD_OCB:
return PGP_AEAD_EAX_OCB_TAG_LEN;
default:
return 0;
}
}
#if defined(ENABLE_AEAD)
bool
pgp_cipher_aead_set_ad(pgp_crypt_t *crypt, const uint8_t *ad, size_t len)
{
return botan_cipher_set_associated_data(crypt->aead.obj, ad, len) == 0;
}
bool
pgp_cipher_aead_start(pgp_crypt_t *crypt, const uint8_t *nonce, size_t len)
{
return botan_cipher_start(crypt->aead.obj, nonce, len) == 0;
}
bool
pgp_cipher_aead_update(pgp_crypt_t *crypt, uint8_t *out, const uint8_t *in, size_t len)
{
size_t outwr = 0;
size_t inread = 0;
if (len % crypt->aead.granularity) {
RNP_LOG("aead wrong update len");
return false;
}
if (botan_cipher_update(crypt->aead.obj, 0, out, len, &outwr, in, len, &inread) != 0) {
RNP_LOG("aead update failed");
return false;
}
if ((outwr != len) || (inread != len)) {
RNP_LOG("wrong aead usage");
return false;
}
return true;
}
void
pgp_cipher_aead_reset(pgp_crypt_t *crypt)
{
botan_cipher_reset(crypt->aead.obj);
}
bool
pgp_cipher_aead_finish(pgp_crypt_t *crypt, uint8_t *out, const uint8_t *in, size_t len)
{
uint32_t flags = BOTAN_CIPHER_UPDATE_FLAG_FINAL;
size_t inread = 0;
size_t outwr = 0;
int res;
if (crypt->aead.decrypt) {
size_t datalen = len - crypt->aead.taglen;
/* for decryption we should have tag for the final update call */
res =
botan_cipher_update(crypt->aead.obj, flags, out, datalen, &outwr, in, len, &inread);
if (res != 0) {
if (res != BOTAN_FFI_ERROR_BAD_MAC) {
RNP_LOG("aead finish failed: %d", res);
}
return false;
}
if ((outwr != datalen) || (inread != len)) {
RNP_LOG("wrong decrypt aead finish usage");
return false;
}
} else {
/* for encryption tag will be generated */
size_t outlen = len + crypt->aead.taglen;
if (botan_cipher_update(
crypt->aead.obj, flags, out, outlen, &outwr, in, len, &inread) != 0) {
RNP_LOG("aead finish failed");
return false;
}
if ((outwr != outlen) || (inread != len)) {
RNP_LOG("wrong encrypt aead finish usage");
return false;
}
}
pgp_cipher_aead_reset(crypt);
return true;
}
void
pgp_cipher_aead_destroy(pgp_crypt_t *crypt)
{
if (crypt->aead.obj) {
botan_cipher_destroy(crypt->aead.obj);
}
memset(crypt, 0x0, sizeof(*crypt));
}
size_t
pgp_cipher_aead_nonce(pgp_aead_alg_t aalg, const uint8_t *iv, uint8_t *nonce, size_t index)
{
switch (aalg) {
case PGP_AEAD_EAX:
/* The nonce for EAX mode is computed by treating the starting
initialization vector as a 16-octet, big-endian value and
exclusive-oring the low eight octets of it with the chunk index.
*/
memcpy(nonce, iv, PGP_AEAD_EAX_NONCE_LEN);
for (int i = 15; (i > 7) && index; i--) {
nonce[i] ^= index & 0xff;
index = index >> 8;
}
return PGP_AEAD_EAX_NONCE_LEN;
case PGP_AEAD_OCB:
/* The nonce for a chunk of chunk index "i" in OCB processing is defined as:
OCB-Nonce_{i} = IV[1..120] xor i
*/
memcpy(nonce, iv, PGP_AEAD_OCB_NONCE_LEN);
for (int i = 14; (i >= 0) && index; i--) {
nonce[i] ^= index & 0xff;
index = index >> 8;
}
return PGP_AEAD_OCB_NONCE_LEN;
default:
return 0;
}
}
#endif // ENABLE_AEAD