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C

/*
* Copyright 2018-2020 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 <string.h>
#include <stdlib.h>
#include <openssl/crypto.h>
#include <openssl/evp.h>
#include <openssl/core_names.h>
#include <openssl/params.h>
#include "internal/endian.h"
#include "crypto/modes.h"
#include "crypto/siv.h"
#ifndef OPENSSL_NO_SIV
__owur static ossl_inline uint32_t rotl8(uint32_t x)
{
return (x << 8) | (x >> 24);
}
__owur static ossl_inline uint32_t rotr8(uint32_t x)
{
return (x >> 8) | (x << 24);
}
__owur static ossl_inline uint64_t byteswap8(uint64_t x)
{
uint32_t high = (uint32_t)(x >> 32);
uint32_t low = (uint32_t)x;
high = (rotl8(high) & 0x00ff00ff) | (rotr8(high) & 0xff00ff00);
low = (rotl8(low) & 0x00ff00ff) | (rotr8(low) & 0xff00ff00);
return ((uint64_t)low) << 32 | (uint64_t)high;
}
__owur static ossl_inline uint64_t siv128_getword(SIV_BLOCK const *b, size_t i)
{
DECLARE_IS_ENDIAN;
if (IS_LITTLE_ENDIAN)
return byteswap8(b->word[i]);
return b->word[i];
}
static ossl_inline void siv128_putword(SIV_BLOCK *b, size_t i, uint64_t x)
{
DECLARE_IS_ENDIAN;
if (IS_LITTLE_ENDIAN)
b->word[i] = byteswap8(x);
else
b->word[i] = x;
}
static ossl_inline void siv128_xorblock(SIV_BLOCK *x,
SIV_BLOCK const *y)
{
x->word[0] ^= y->word[0];
x->word[1] ^= y->word[1];
}
/*
* Doubles |b|, which is 16 bytes representing an element
* of GF(2**128) modulo the irreducible polynomial
* x**128 + x**7 + x**2 + x + 1.
* Assumes two's-complement arithmetic
*/
static ossl_inline void siv128_dbl(SIV_BLOCK *b)
{
uint64_t high = siv128_getword(b, 0);
uint64_t low = siv128_getword(b, 1);
uint64_t high_carry = high & (((uint64_t)1) << 63);
uint64_t low_carry = low & (((uint64_t)1) << 63);
int64_t low_mask = -((int64_t)(high_carry >> 63)) & 0x87;
uint64_t high_mask = low_carry >> 63;
high = (high << 1) | high_mask;
low = (low << 1) ^ (uint64_t)low_mask;
siv128_putword(b, 0, high);
siv128_putword(b, 1, low);
}
__owur static ossl_inline int siv128_do_s2v_p(SIV128_CONTEXT *ctx, SIV_BLOCK *out,
unsigned char const* in, size_t len)
{
SIV_BLOCK t;
size_t out_len = sizeof(out->byte);
EVP_MAC_CTX *mac_ctx;
int ret = 0;
mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init);
if (mac_ctx == NULL)
return 0;
if (len >= SIV_LEN) {
if (!EVP_MAC_update(mac_ctx, in, len - SIV_LEN))
goto err;
memcpy(&t, in + (len-SIV_LEN), SIV_LEN);
siv128_xorblock(&t, &ctx->d);
if (!EVP_MAC_update(mac_ctx, t.byte, SIV_LEN))
goto err;
} else {
memset(&t, 0, sizeof(t));
memcpy(&t, in, len);
t.byte[len] = 0x80;
siv128_dbl(&ctx->d);
siv128_xorblock(&t, &ctx->d);
if (!EVP_MAC_update(mac_ctx, t.byte, SIV_LEN))
goto err;
}
if (!EVP_MAC_final(mac_ctx, out->byte, &out_len, sizeof(out->byte))
|| out_len != SIV_LEN)
goto err;
ret = 1;
err:
EVP_MAC_CTX_free(mac_ctx);
return ret;
}
__owur static ossl_inline int siv128_do_encrypt(EVP_CIPHER_CTX *ctx, unsigned char *out,
unsigned char const *in, size_t len,
SIV_BLOCK *icv)
{
int out_len = (int)len;
if (!EVP_CipherInit_ex(ctx, NULL, NULL, NULL, icv->byte, 1))
return 0;
return EVP_EncryptUpdate(ctx, out, &out_len, in, out_len);
}
/*
* Create a new SIV128_CONTEXT
*/
SIV128_CONTEXT *CRYPTO_siv128_new(const unsigned char *key, int klen,
EVP_CIPHER *cbc, EVP_CIPHER *ctr,
OPENSSL_CTX *libctx, const char *propq)
{
SIV128_CONTEXT *ctx;
int ret;
if ((ctx = OPENSSL_malloc(sizeof(*ctx))) != NULL) {
ret = CRYPTO_siv128_init(ctx, key, klen, cbc, ctr, libctx, propq);
if (ret)
return ctx;
OPENSSL_free(ctx);
}
return NULL;
}
/*
* Initialise an existing SIV128_CONTEXT
*/
int CRYPTO_siv128_init(SIV128_CONTEXT *ctx, const unsigned char *key, int klen,
const EVP_CIPHER *cbc, const EVP_CIPHER *ctr,
OPENSSL_CTX *libctx, const char *propq)
{
static const unsigned char zero[SIV_LEN] = { 0 };
size_t out_len = SIV_LEN;
EVP_MAC_CTX *mac_ctx = NULL;
OSSL_PARAM params[3];
const char *cbc_name;
if (ctx == NULL)
return 0;
memset(&ctx->d, 0, sizeof(ctx->d));
EVP_CIPHER_CTX_free(ctx->cipher_ctx);
EVP_MAC_CTX_free(ctx->mac_ctx_init);
EVP_MAC_free(ctx->mac);
ctx->mac = NULL;
ctx->cipher_ctx = NULL;
ctx->mac_ctx_init = NULL;
if (key == NULL || cbc == NULL || ctr == NULL)
return 0;
cbc_name = EVP_CIPHER_name(cbc);
params[0] = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_CIPHER,
(char *)cbc_name, 0);
params[1] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
(void *)key, klen);
params[2] = OSSL_PARAM_construct_end();
if ((ctx->cipher_ctx = EVP_CIPHER_CTX_new()) == NULL
|| (ctx->mac =
EVP_MAC_fetch(libctx, OSSL_MAC_NAME_CMAC, propq)) == NULL
|| (ctx->mac_ctx_init = EVP_MAC_CTX_new(ctx->mac)) == NULL
|| !EVP_MAC_CTX_set_params(ctx->mac_ctx_init, params)
|| !EVP_EncryptInit_ex(ctx->cipher_ctx, ctr, NULL, key + klen, NULL)
|| (mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
|| !EVP_MAC_update(mac_ctx, zero, sizeof(zero))
|| !EVP_MAC_final(mac_ctx, ctx->d.byte, &out_len,
sizeof(ctx->d.byte))) {
EVP_CIPHER_CTX_free(ctx->cipher_ctx);
EVP_MAC_CTX_free(ctx->mac_ctx_init);
EVP_MAC_CTX_free(mac_ctx);
EVP_MAC_free(ctx->mac);
return 0;
}
EVP_MAC_CTX_free(mac_ctx);
ctx->final_ret = -1;
ctx->crypto_ok = 1;
return 1;
}
/*
* Copy an SIV128_CONTEXT object
*/
int CRYPTO_siv128_copy_ctx(SIV128_CONTEXT *dest, SIV128_CONTEXT *src)
{
memcpy(&dest->d, &src->d, sizeof(src->d));
if (dest->cipher_ctx == NULL) {
dest->cipher_ctx = EVP_CIPHER_CTX_new();
if (dest->cipher_ctx == NULL)
return 0;
}
if (!EVP_CIPHER_CTX_copy(dest->cipher_ctx, src->cipher_ctx))
return 0;
EVP_MAC_CTX_free(dest->mac_ctx_init);
dest->mac_ctx_init = EVP_MAC_CTX_dup(src->mac_ctx_init);
if (dest->mac_ctx_init == NULL)
return 0;
dest->mac = src->mac;
if (dest->mac != NULL)
EVP_MAC_up_ref(dest->mac);
return 1;
}
/*
* Provide any AAD. This can be called multiple times.
* Per RFC5297, the last piece of associated data
* is the nonce, but it's not treated special
*/
int CRYPTO_siv128_aad(SIV128_CONTEXT *ctx, const unsigned char *aad,
size_t len)
{
SIV_BLOCK mac_out;
size_t out_len = SIV_LEN;
EVP_MAC_CTX *mac_ctx;
siv128_dbl(&ctx->d);
if ((mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
|| !EVP_MAC_update(mac_ctx, aad, len)
|| !EVP_MAC_final(mac_ctx, mac_out.byte, &out_len,
sizeof(mac_out.byte))
|| out_len != SIV_LEN) {
EVP_MAC_CTX_free(mac_ctx);
return 0;
}
EVP_MAC_CTX_free(mac_ctx);
siv128_xorblock(&ctx->d, &mac_out);
return 1;
}
/*
* Provide any data to be encrypted. This can be called once.
*/
int CRYPTO_siv128_encrypt(SIV128_CONTEXT *ctx,
const unsigned char *in, unsigned char *out,
size_t len)
{
SIV_BLOCK q;
/* can only do one crypto operation */
if (ctx->crypto_ok == 0)
return 0;
ctx->crypto_ok--;
if (!siv128_do_s2v_p(ctx, &q, in, len))
return 0;
memcpy(ctx->tag.byte, &q, SIV_LEN);
q.byte[8] &= 0x7f;
q.byte[12] &= 0x7f;
if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q))
return 0;
ctx->final_ret = 0;
return len;
}
/*
* Provide any data to be decrypted. This can be called once.
*/
int CRYPTO_siv128_decrypt(SIV128_CONTEXT *ctx,
const unsigned char *in, unsigned char *out,
size_t len)
{
unsigned char* p;
SIV_BLOCK t, q;
int i;
/* can only do one crypto operation */
if (ctx->crypto_ok == 0)
return 0;
ctx->crypto_ok--;
memcpy(&q, ctx->tag.byte, SIV_LEN);
q.byte[8] &= 0x7f;
q.byte[12] &= 0x7f;
if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q)
|| !siv128_do_s2v_p(ctx, &t, out, len))
return 0;
p = ctx->tag.byte;
for (i = 0; i < SIV_LEN; i++)
t.byte[i] ^= p[i];
if ((t.word[0] | t.word[1]) != 0) {
OPENSSL_cleanse(out, len);
return 0;
}
ctx->final_ret = 0;
return len;
}
/*
* Return the already calculated final result.
*/
int CRYPTO_siv128_finish(SIV128_CONTEXT *ctx)
{
return ctx->final_ret;
}
/*
* Set the tag
*/
int CRYPTO_siv128_set_tag(SIV128_CONTEXT *ctx, const unsigned char *tag, size_t len)
{
if (len != SIV_LEN)
return 0;
/* Copy the tag from the supplied buffer */
memcpy(ctx->tag.byte, tag, len);
return 1;
}
/*
* Retrieve the calculated tag
*/
int CRYPTO_siv128_get_tag(SIV128_CONTEXT *ctx, unsigned char *tag, size_t len)
{
if (len != SIV_LEN)
return 0;
/* Copy the tag into the supplied buffer */
memcpy(tag, ctx->tag.byte, len);
return 1;
}
/*
* Release all resources
*/
int CRYPTO_siv128_cleanup(SIV128_CONTEXT *ctx)
{
if (ctx != NULL) {
EVP_CIPHER_CTX_free(ctx->cipher_ctx);
ctx->cipher_ctx = NULL;
EVP_MAC_CTX_free(ctx->mac_ctx_init);
ctx->mac_ctx_init = NULL;
EVP_MAC_free(ctx->mac);
ctx->mac = NULL;
OPENSSL_cleanse(&ctx->d, sizeof(ctx->d));
OPENSSL_cleanse(&ctx->tag, sizeof(ctx->tag));
ctx->final_ret = -1;
ctx->crypto_ok = 1;
}
return 1;
}
int CRYPTO_siv128_speed(SIV128_CONTEXT *ctx, int arg)
{
ctx->crypto_ok = (arg == 1) ? -1 : 1;
return 1;
}
#endif /* OPENSSL_NO_SIV */