/*
* Copyright 2019-2021 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
*/
/*
* AES low level APIs are deprecated for public use, but still ok for internal
* use where we're using them to implement the higher level EVP interface, as is
* the case here.
*/
#include "internal/deprecated.h"
#include <openssl/proverr.h>
#include "cipher_aes_xts.h"
#include "prov/implementations.h"
#include "prov/providercommon.h"
#define AES_XTS_FLAGS PROV_CIPHER_FLAG_CUSTOM_IV
#define AES_XTS_IV_BITS 128
#define AES_XTS_BLOCK_BITS 8
/* forward declarations */
static OSSL_FUNC_cipher_encrypt_init_fn aes_xts_einit;
static OSSL_FUNC_cipher_decrypt_init_fn aes_xts_dinit;
static OSSL_FUNC_cipher_update_fn aes_xts_stream_update;
static OSSL_FUNC_cipher_final_fn aes_xts_stream_final;
static OSSL_FUNC_cipher_cipher_fn aes_xts_cipher;
static OSSL_FUNC_cipher_freectx_fn aes_xts_freectx;
static OSSL_FUNC_cipher_dupctx_fn aes_xts_dupctx;
static OSSL_FUNC_cipher_set_ctx_params_fn aes_xts_set_ctx_params;
static OSSL_FUNC_cipher_settable_ctx_params_fn aes_xts_settable_ctx_params;
/*
* Verify that the two keys are different.
*
* This addresses the vulnerability described in Rogaway's
* September 2004 paper:
*
* "Efficient Instantiations of Tweakable Blockciphers and
* Refinements to Modes OCB and PMAC".
* (http://web.cs.ucdavis.edu/~rogaway/papers/offsets.pdf)
*
* FIPS 140-2 IG A.9 XTS-AES Key Generation Requirements states
* that:
* "The check for Key_1 != Key_2 shall be done at any place
* BEFORE using the keys in the XTS-AES algorithm to process
* data with them."
*/
static int aes_xts_check_keys_differ(const unsigned char *key, size_t bytes,
int enc)
{
if ((!ossl_aes_xts_allow_insecure_decrypt || enc)
&& CRYPTO_memcmp(key, key + bytes, bytes) == 0) {
ERR_raise(ERR_LIB_PROV, PROV_R_XTS_DUPLICATED_KEYS);
return 0;
}
return 1;
}
/*-
* Provider dispatch functions
*/
static int aes_xts_init(void *vctx, const unsigned char *key, size_t keylen,
const unsigned char *iv, size_t ivlen,
const OSSL_PARAM params[], int enc)
{
PROV_AES_XTS_CTX *xctx = (PROV_AES_XTS_CTX *)vctx;
PROV_CIPHER_CTX *ctx = &xctx->base;
if (!ossl_prov_is_running())
return 0;
ctx->enc = enc;
if (iv != NULL) {
if (!ossl_cipher_generic_initiv(vctx, iv, ivlen))
return 0;
}
if (key != NULL) {
if (keylen != ctx->keylen) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
return 0;
}
if (!aes_xts_check_keys_differ(key, keylen / 2, enc))
return 0;
if (!ctx->hw->init(ctx, key, keylen))
return 0;
}
return aes_xts_set_ctx_params(ctx, params);
}
static int aes_xts_einit(void *vctx, const unsigned char *key, size_t keylen,
const unsigned char *iv, size_t ivlen,
const OSSL_PARAM params[])
{
return aes_xts_init(vctx, key, keylen, iv, ivlen, params, 1);
}
static int aes_xts_dinit(void *vctx, const unsigned char *key, size_t keylen,
const unsigned char *iv, size_t ivlen,
const OSSL_PARAM params[])
{
return aes_xts_init(vctx, key, keylen, iv, ivlen, params, 0);
}
static void *aes_xts_newctx(void *provctx, unsigned int mode, uint64_t flags,
size_t kbits, size_t blkbits, size_t ivbits)
{
PROV_AES_XTS_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
if (ctx != NULL) {
ossl_cipher_generic_initkey(&ctx->base, kbits, blkbits, ivbits, mode,
flags, ossl_prov_cipher_hw_aes_xts(kbits),
NULL);
}
return ctx;
}
static void aes_xts_freectx(void *vctx)
{
PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
ossl_cipher_generic_reset_ctx((PROV_CIPHER_CTX *)vctx);
OPENSSL_clear_free(ctx, sizeof(*ctx));
}
static void *aes_xts_dupctx(void *vctx)
{
PROV_AES_XTS_CTX *in = (PROV_AES_XTS_CTX *)vctx;
PROV_AES_XTS_CTX *ret = NULL;
if (!ossl_prov_is_running())
return NULL;
if (in->xts.key1 != NULL) {
if (in->xts.key1 != &in->ks1)
return NULL;
}
if (in->xts.key2 != NULL) {
if (in->xts.key2 != &in->ks2)
return NULL;
}
ret = OPENSSL_malloc(sizeof(*ret));
if (ret == NULL) {
ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
return NULL;
}
in->base.hw->copyctx(&ret->base, &in->base);
return ret;
}
static int aes_xts_cipher(void *vctx, unsigned char *out, size_t *outl,
size_t outsize, const unsigned char *in, size_t inl)
{
PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
if (!ossl_prov_is_running()
|| ctx->xts.key1 == NULL
|| ctx->xts.key2 == NULL
|| !ctx->base.iv_set
|| out == NULL
|| in == NULL
|| inl < AES_BLOCK_SIZE)
return 0;
/*
* Impose a limit of 2^20 blocks per data unit as specified by
* IEEE Std 1619-2018. The earlier and obsolete IEEE Std 1619-2007
* indicated that this was a SHOULD NOT rather than a MUST NOT.
* NIST SP 800-38E mandates the same limit.
*/
if (inl > XTS_MAX_BLOCKS_PER_DATA_UNIT * AES_BLOCK_SIZE) {
ERR_raise(ERR_LIB_PROV, PROV_R_XTS_DATA_UNIT_IS_TOO_LARGE);
return 0;
}
if (ctx->stream != NULL)
(*ctx->stream)(in, out, inl, ctx->xts.key1, ctx->xts.key2, ctx->base.iv);
else if (CRYPTO_xts128_encrypt(&ctx->xts, ctx->base.iv, in, out, inl,
ctx->base.enc))
return 0;
*outl = inl;
return 1;
}
static int aes_xts_stream_update(void *vctx, unsigned char *out, size_t *outl,
size_t outsize, const unsigned char *in,
size_t inl)
{
PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
if (outsize < inl) {
ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
return 0;
}
if (!aes_xts_cipher(ctx, out, outl, outsize, in, inl)) {
ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
return 0;
}
return 1;
}
static int aes_xts_stream_final(void *vctx, unsigned char *out, size_t *outl,
size_t outsize)
{
if (!ossl_prov_is_running())
return 0;
*outl = 0;
return 1;
}
static const OSSL_PARAM aes_xts_known_settable_ctx_params[] = {
OSSL_PARAM_size_t(OSSL_CIPHER_PARAM_KEYLEN, NULL),
OSSL_PARAM_END
};
static const OSSL_PARAM *aes_xts_settable_ctx_params(ossl_unused void *cctx,
ossl_unused void *provctx)
{
return aes_xts_known_settable_ctx_params;
}
static int aes_xts_set_ctx_params(void *vctx, const OSSL_PARAM params[])
{
PROV_CIPHER_CTX *ctx = (PROV_CIPHER_CTX *)vctx;
const OSSL_PARAM *p;
if (params == NULL)
return 1;
p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_KEYLEN);
if (p != NULL) {
size_t keylen;
if (!OSSL_PARAM_get_size_t(p, &keylen)) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
return 0;
}
/* The key length can not be modified for xts mode */
if (keylen != ctx->keylen)
return 0;
}
return 1;
}
#define IMPLEMENT_cipher(lcmode, UCMODE, kbits, flags) \
static OSSL_FUNC_cipher_get_params_fn aes_##kbits##_##lcmode##_get_params; \
static int aes_##kbits##_##lcmode##_get_params(OSSL_PARAM params[]) \
{ \
return ossl_cipher_generic_get_params(params, EVP_CIPH_##UCMODE##_MODE, \
flags, 2 * kbits, AES_XTS_BLOCK_BITS, \
AES_XTS_IV_BITS); \
} \
static OSSL_FUNC_cipher_newctx_fn aes_##kbits##_xts_newctx; \
static void *aes_##kbits##_xts_newctx(void *provctx) \
{ \
return aes_xts_newctx(provctx, EVP_CIPH_##UCMODE##_MODE, flags, 2 * kbits, \
AES_XTS_BLOCK_BITS, AES_XTS_IV_BITS); \
} \
const OSSL_DISPATCH ossl_aes##kbits##xts_functions[] = { \
{ OSSL_FUNC_CIPHER_NEWCTX, (void (*)(void))aes_##kbits##_xts_newctx }, \
{ OSSL_FUNC_CIPHER_ENCRYPT_INIT, (void (*)(void))aes_xts_einit }, \
{ OSSL_FUNC_CIPHER_DECRYPT_INIT, (void (*)(void))aes_xts_dinit }, \
{ OSSL_FUNC_CIPHER_UPDATE, (void (*)(void))aes_xts_stream_update }, \
{ OSSL_FUNC_CIPHER_FINAL, (void (*)(void))aes_xts_stream_final }, \
{ OSSL_FUNC_CIPHER_CIPHER, (void (*)(void))aes_xts_cipher }, \
{ OSSL_FUNC_CIPHER_FREECTX, (void (*)(void))aes_xts_freectx }, \
{ OSSL_FUNC_CIPHER_DUPCTX, (void (*)(void))aes_xts_dupctx }, \
{ OSSL_FUNC_CIPHER_GET_PARAMS, \
(void (*)(void))aes_##kbits##_##lcmode##_get_params }, \
{ OSSL_FUNC_CIPHER_GETTABLE_PARAMS, \
(void (*)(void))ossl_cipher_generic_gettable_params }, \
{ OSSL_FUNC_CIPHER_GET_CTX_PARAMS, \
(void (*)(void))ossl_cipher_generic_get_ctx_params }, \
{ OSSL_FUNC_CIPHER_GETTABLE_CTX_PARAMS, \
(void (*)(void))ossl_cipher_generic_gettable_ctx_params }, \
{ OSSL_FUNC_CIPHER_SET_CTX_PARAMS, \
(void (*)(void))aes_xts_set_ctx_params }, \
{ OSSL_FUNC_CIPHER_SETTABLE_CTX_PARAMS, \
(void (*)(void))aes_xts_settable_ctx_params }, \
{ 0, NULL } \
}
IMPLEMENT_cipher(xts, XTS, 256, AES_XTS_FLAGS);
IMPLEMENT_cipher(xts, XTS, 128, AES_XTS_FLAGS);