2 * Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
11 * AES low level APIs are deprecated for public use, but still ok for internal
12 * use where we're using them to implement the higher level EVP interface, as is
15 #include "internal/deprecated.h"
17 #include "cipher_aes_xts.h"
18 #include "prov/implementations.h"
19 #include "prov/providercommonerr.h"
21 /* TODO (3.0) Figure out what flags need to be set */
22 #define AES_XTS_FLAGS (EVP_CIPH_CUSTOM_IV \
23 | EVP_CIPH_ALWAYS_CALL_INIT \
24 | EVP_CIPH_CTRL_INIT \
25 | EVP_CIPH_CUSTOM_COPY)
27 #define AES_XTS_IV_BITS 128
28 #define AES_XTS_BLOCK_BITS 8
30 /* forward declarations */
31 static OSSL_FUNC_cipher_encrypt_init_fn aes_xts_einit;
32 static OSSL_FUNC_cipher_decrypt_init_fn aes_xts_dinit;
33 static OSSL_FUNC_cipher_update_fn aes_xts_stream_update;
34 static OSSL_FUNC_cipher_final_fn aes_xts_stream_final;
35 static OSSL_FUNC_cipher_cipher_fn aes_xts_cipher;
36 static OSSL_FUNC_cipher_freectx_fn aes_xts_freectx;
37 static OSSL_FUNC_cipher_dupctx_fn aes_xts_dupctx;
38 static OSSL_FUNC_cipher_set_ctx_params_fn aes_xts_set_ctx_params;
39 static OSSL_FUNC_cipher_settable_ctx_params_fn aes_xts_settable_ctx_params;
42 * Verify that the two keys are different.
44 * This addresses the vulnerability described in Rogaway's
45 * September 2004 paper:
47 * "Efficient Instantiations of Tweakable Blockciphers and
48 * Refinements to Modes OCB and PMAC".
49 * (http://web.cs.ucdavis.edu/~rogaway/papers/offsets.pdf)
51 * FIPS 140-2 IG A.9 XTS-AES Key Generation Requirements states
53 * "The check for Key_1 != Key_2 shall be done at any place
54 * BEFORE using the keys in the XTS-AES algorithm to process
57 static int aes_xts_check_keys_differ(const unsigned char *key, size_t bytes,
60 if ((!allow_insecure_decrypt || enc)
61 && CRYPTO_memcmp(key, key + bytes, bytes) == 0) {
62 ERR_raise(ERR_LIB_PROV, PROV_R_XTS_DUPLICATED_KEYS);
69 * Provider dispatch functions
71 static int aes_xts_init(void *vctx, const unsigned char *key, size_t keylen,
72 const unsigned char *iv, size_t ivlen, int enc)
74 PROV_AES_XTS_CTX *xctx = (PROV_AES_XTS_CTX *)vctx;
75 PROV_CIPHER_CTX *ctx = &xctx->base;
80 if (!cipher_generic_initiv(vctx, iv, ivlen))
84 if (keylen != ctx->keylen) {
85 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
88 if (!aes_xts_check_keys_differ(key, keylen / 2, enc))
90 return ctx->hw->init(ctx, key, keylen);
95 static int aes_xts_einit(void *vctx, const unsigned char *key, size_t keylen,
96 const unsigned char *iv, size_t ivlen)
98 return aes_xts_init(vctx, key, keylen, iv, ivlen, 1);
101 static int aes_xts_dinit(void *vctx, const unsigned char *key, size_t keylen,
102 const unsigned char *iv, size_t ivlen)
104 return aes_xts_init(vctx, key, keylen, iv, ivlen, 0);
107 static void *aes_xts_newctx(void *provctx, unsigned int mode, uint64_t flags,
108 size_t kbits, size_t blkbits, size_t ivbits)
110 PROV_AES_XTS_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
113 cipher_generic_initkey(&ctx->base, kbits, blkbits, ivbits, mode, flags,
114 PROV_CIPHER_HW_aes_xts(kbits), NULL);
119 static void aes_xts_freectx(void *vctx)
121 PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
123 OPENSSL_clear_free(ctx, sizeof(*ctx));
126 static void *aes_xts_dupctx(void *vctx)
128 PROV_AES_XTS_CTX *in = (PROV_AES_XTS_CTX *)vctx;
129 PROV_AES_XTS_CTX *ret = NULL;
131 if (in->xts.key1 != NULL) {
132 if (in->xts.key1 != &in->ks1)
135 if (in->xts.key2 != NULL) {
136 if (in->xts.key2 != &in->ks2)
139 ret = OPENSSL_malloc(sizeof(*ret));
141 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
144 in->base.hw->copyctx(&ret->base, &in->base);
148 static int aes_xts_cipher(void *vctx, unsigned char *out, size_t *outl,
149 size_t outsize, const unsigned char *in, size_t inl)
151 PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
153 if (ctx->xts.key1 == NULL
154 || ctx->xts.key2 == NULL
158 || inl < AES_BLOCK_SIZE)
162 * Impose a limit of 2^20 blocks per data unit as specified by
163 * IEEE Std 1619-2018. The earlier and obsolete IEEE Std 1619-2007
164 * indicated that this was a SHOULD NOT rather than a MUST NOT.
165 * NIST SP 800-38E mandates the same limit.
167 if (inl > XTS_MAX_BLOCKS_PER_DATA_UNIT * AES_BLOCK_SIZE) {
168 ERR_raise(ERR_LIB_PROV, PROV_R_XTS_DATA_UNIT_IS_TOO_LARGE);
172 if (ctx->stream != NULL)
173 (*ctx->stream)(in, out, inl, ctx->xts.key1, ctx->xts.key2, ctx->base.iv);
174 else if (CRYPTO_xts128_encrypt(&ctx->xts, ctx->base.iv, in, out, inl,
182 static int aes_xts_stream_update(void *vctx, unsigned char *out, size_t *outl,
183 size_t outsize, const unsigned char *in,
186 PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
189 ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
193 if (!aes_xts_cipher(ctx, out, outl, outsize, in, inl)) {
194 ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
201 static int aes_xts_stream_final(void *vctx, unsigned char *out, size_t *outl,
208 static const OSSL_PARAM aes_xts_known_settable_ctx_params[] = {
209 OSSL_PARAM_size_t(OSSL_CIPHER_PARAM_KEYLEN, NULL),
213 static const OSSL_PARAM *aes_xts_settable_ctx_params(void)
215 return aes_xts_known_settable_ctx_params;
218 static int aes_xts_set_ctx_params(void *vctx, const OSSL_PARAM params[])
220 PROV_CIPHER_CTX *ctx = (PROV_CIPHER_CTX *)vctx;
224 * TODO(3.0) We need a general solution for handling missing parameters
225 * inside set_params and get_params methods.
227 p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_KEYLEN);
231 if (!OSSL_PARAM_get_size_t(p, &keylen)) {
232 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
235 /* The key length can not be modified for xts mode */
236 if (keylen != ctx->keylen)
243 #define IMPLEMENT_cipher(lcmode, UCMODE, kbits, flags) \
244 static OSSL_FUNC_cipher_get_params_fn aes_##kbits##_##lcmode##_get_params; \
245 static int aes_##kbits##_##lcmode##_get_params(OSSL_PARAM params[]) \
247 return cipher_generic_get_params(params, EVP_CIPH_##UCMODE##_MODE, \
248 flags, 2 * kbits, AES_XTS_BLOCK_BITS, \
251 static OSSL_FUNC_cipher_newctx_fn aes_##kbits##_xts_newctx; \
252 static void *aes_##kbits##_xts_newctx(void *provctx) \
254 return aes_xts_newctx(provctx, EVP_CIPH_##UCMODE##_MODE, flags, 2 * kbits, \
255 AES_XTS_BLOCK_BITS, AES_XTS_IV_BITS); \
257 const OSSL_DISPATCH aes##kbits##xts_functions[] = { \
258 { OSSL_FUNC_CIPHER_NEWCTX, (void (*)(void))aes_##kbits##_xts_newctx }, \
259 { OSSL_FUNC_CIPHER_ENCRYPT_INIT, (void (*)(void))aes_xts_einit }, \
260 { OSSL_FUNC_CIPHER_DECRYPT_INIT, (void (*)(void))aes_xts_dinit }, \
261 { OSSL_FUNC_CIPHER_UPDATE, (void (*)(void))aes_xts_stream_update }, \
262 { OSSL_FUNC_CIPHER_FINAL, (void (*)(void))aes_xts_stream_final }, \
263 { OSSL_FUNC_CIPHER_CIPHER, (void (*)(void))aes_xts_cipher }, \
264 { OSSL_FUNC_CIPHER_FREECTX, (void (*)(void))aes_xts_freectx }, \
265 { OSSL_FUNC_CIPHER_DUPCTX, (void (*)(void))aes_xts_dupctx }, \
266 { OSSL_FUNC_CIPHER_GET_PARAMS, \
267 (void (*)(void))aes_##kbits##_##lcmode##_get_params }, \
268 { OSSL_FUNC_CIPHER_GETTABLE_PARAMS, \
269 (void (*)(void))cipher_generic_gettable_params }, \
270 { OSSL_FUNC_CIPHER_GET_CTX_PARAMS, \
271 (void (*)(void))cipher_generic_get_ctx_params }, \
272 { OSSL_FUNC_CIPHER_GETTABLE_CTX_PARAMS, \
273 (void (*)(void))cipher_generic_gettable_ctx_params }, \
274 { OSSL_FUNC_CIPHER_SET_CTX_PARAMS, \
275 (void (*)(void))aes_xts_set_ctx_params }, \
276 { OSSL_FUNC_CIPHER_SETTABLE_CTX_PARAMS, \
277 (void (*)(void))aes_xts_settable_ctx_params }, \
281 IMPLEMENT_cipher(xts, XTS, 256, AES_XTS_FLAGS);
282 IMPLEMENT_cipher(xts, XTS, 128, AES_XTS_FLAGS);