3 * Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
5 * Licensed under the Apache License 2.0 (the "License"). You may not use
6 * this file except in compliance with the License. You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
12 * AES low level APIs are deprecated for public use, but still ok for internal
13 * use where we're using them to implement the higher level EVP interface, as is
16 #include "internal/deprecated.h"
18 #include <openssl/proverr.h>
19 #include "cipher_aes_xts.h"
20 #include "prov/implementations.h"
21 #include "prov/providercommon.h"
23 #define AES_XTS_FLAGS PROV_CIPHER_FLAG_CUSTOM_IV
24 #define AES_XTS_IV_BITS 128
25 #define AES_XTS_BLOCK_BITS 8
27 /* forward declarations */
28 static OSSL_FUNC_cipher_encrypt_init_fn aes_xts_einit;
29 static OSSL_FUNC_cipher_decrypt_init_fn aes_xts_dinit;
30 static OSSL_FUNC_cipher_update_fn aes_xts_stream_update;
31 static OSSL_FUNC_cipher_final_fn aes_xts_stream_final;
32 static OSSL_FUNC_cipher_cipher_fn aes_xts_cipher;
33 static OSSL_FUNC_cipher_freectx_fn aes_xts_freectx;
34 static OSSL_FUNC_cipher_dupctx_fn aes_xts_dupctx;
35 static OSSL_FUNC_cipher_set_ctx_params_fn aes_xts_set_ctx_params;
36 static OSSL_FUNC_cipher_settable_ctx_params_fn aes_xts_settable_ctx_params;
39 * Verify that the two keys are different.
41 * This addresses the vulnerability described in Rogaway's
42 * September 2004 paper:
44 * "Efficient Instantiations of Tweakable Blockciphers and
45 * Refinements to Modes OCB and PMAC".
46 * (http://web.cs.ucdavis.edu/~rogaway/papers/offsets.pdf)
48 * FIPS 140-2 IG A.9 XTS-AES Key Generation Requirements states
50 * "The check for Key_1 != Key_2 shall be done at any place
51 * BEFORE using the keys in the XTS-AES algorithm to process
54 static int aes_xts_check_keys_differ(const unsigned char *key, size_t bytes,
57 if ((!allow_insecure_decrypt || enc)
58 && CRYPTO_memcmp(key, key + bytes, bytes) == 0) {
59 ERR_raise(ERR_LIB_PROV, PROV_R_XTS_DUPLICATED_KEYS);
66 * Provider dispatch functions
68 static int aes_xts_init(void *vctx, const unsigned char *key, size_t keylen,
69 const unsigned char *iv, size_t ivlen, int enc)
71 PROV_AES_XTS_CTX *xctx = (PROV_AES_XTS_CTX *)vctx;
72 PROV_CIPHER_CTX *ctx = &xctx->base;
74 if (!ossl_prov_is_running())
80 if (!ossl_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 ossl_cipher_generic_initkey(&ctx->base, kbits, blkbits, ivbits, mode,
114 flags, ossl_prov_cipher_hw_aes_xts(kbits),
120 static void aes_xts_freectx(void *vctx)
122 PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
124 ossl_cipher_generic_reset_ctx((PROV_CIPHER_CTX *)vctx);
125 OPENSSL_clear_free(ctx, sizeof(*ctx));
128 static void *aes_xts_dupctx(void *vctx)
130 PROV_AES_XTS_CTX *in = (PROV_AES_XTS_CTX *)vctx;
131 PROV_AES_XTS_CTX *ret = NULL;
133 if (!ossl_prov_is_running())
136 if (in->xts.key1 != NULL) {
137 if (in->xts.key1 != &in->ks1)
140 if (in->xts.key2 != NULL) {
141 if (in->xts.key2 != &in->ks2)
144 ret = OPENSSL_malloc(sizeof(*ret));
146 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
149 in->base.hw->copyctx(&ret->base, &in->base);
153 static int aes_xts_cipher(void *vctx, unsigned char *out, size_t *outl,
154 size_t outsize, const unsigned char *in, size_t inl)
156 PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
158 if (!ossl_prov_is_running()
159 || ctx->xts.key1 == NULL
160 || ctx->xts.key2 == NULL
164 || inl < AES_BLOCK_SIZE)
168 * Impose a limit of 2^20 blocks per data unit as specified by
169 * IEEE Std 1619-2018. The earlier and obsolete IEEE Std 1619-2007
170 * indicated that this was a SHOULD NOT rather than a MUST NOT.
171 * NIST SP 800-38E mandates the same limit.
173 if (inl > XTS_MAX_BLOCKS_PER_DATA_UNIT * AES_BLOCK_SIZE) {
174 ERR_raise(ERR_LIB_PROV, PROV_R_XTS_DATA_UNIT_IS_TOO_LARGE);
178 if (ctx->stream != NULL)
179 (*ctx->stream)(in, out, inl, ctx->xts.key1, ctx->xts.key2, ctx->base.iv);
180 else if (CRYPTO_xts128_encrypt(&ctx->xts, ctx->base.iv, in, out, inl,
188 static int aes_xts_stream_update(void *vctx, unsigned char *out, size_t *outl,
189 size_t outsize, const unsigned char *in,
192 PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
195 ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
199 if (!aes_xts_cipher(ctx, out, outl, outsize, in, inl)) {
200 ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
207 static int aes_xts_stream_final(void *vctx, unsigned char *out, size_t *outl,
210 if (!ossl_prov_is_running())
216 static const OSSL_PARAM aes_xts_known_settable_ctx_params[] = {
217 OSSL_PARAM_size_t(OSSL_CIPHER_PARAM_KEYLEN, NULL),
221 static const OSSL_PARAM *aes_xts_settable_ctx_params(ossl_unused void *provctx)
223 return aes_xts_known_settable_ctx_params;
226 static int aes_xts_set_ctx_params(void *vctx, const OSSL_PARAM params[])
228 PROV_CIPHER_CTX *ctx = (PROV_CIPHER_CTX *)vctx;
231 p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_KEYLEN);
235 if (!OSSL_PARAM_get_size_t(p, &keylen)) {
236 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
239 /* The key length can not be modified for xts mode */
240 if (keylen != ctx->keylen)
247 #define IMPLEMENT_cipher(lcmode, UCMODE, kbits, flags) \
248 static OSSL_FUNC_cipher_get_params_fn aes_##kbits##_##lcmode##_get_params; \
249 static int aes_##kbits##_##lcmode##_get_params(OSSL_PARAM params[]) \
251 return ossl_cipher_generic_get_params(params, EVP_CIPH_##UCMODE##_MODE, \
252 flags, 2 * kbits, AES_XTS_BLOCK_BITS, \
255 static OSSL_FUNC_cipher_newctx_fn aes_##kbits##_xts_newctx; \
256 static void *aes_##kbits##_xts_newctx(void *provctx) \
258 return aes_xts_newctx(provctx, EVP_CIPH_##UCMODE##_MODE, flags, 2 * kbits, \
259 AES_XTS_BLOCK_BITS, AES_XTS_IV_BITS); \
261 const OSSL_DISPATCH ossl_aes##kbits##xts_functions[] = { \
262 { OSSL_FUNC_CIPHER_NEWCTX, (void (*)(void))aes_##kbits##_xts_newctx }, \
263 { OSSL_FUNC_CIPHER_ENCRYPT_INIT, (void (*)(void))aes_xts_einit }, \
264 { OSSL_FUNC_CIPHER_DECRYPT_INIT, (void (*)(void))aes_xts_dinit }, \
265 { OSSL_FUNC_CIPHER_UPDATE, (void (*)(void))aes_xts_stream_update }, \
266 { OSSL_FUNC_CIPHER_FINAL, (void (*)(void))aes_xts_stream_final }, \
267 { OSSL_FUNC_CIPHER_CIPHER, (void (*)(void))aes_xts_cipher }, \
268 { OSSL_FUNC_CIPHER_FREECTX, (void (*)(void))aes_xts_freectx }, \
269 { OSSL_FUNC_CIPHER_DUPCTX, (void (*)(void))aes_xts_dupctx }, \
270 { OSSL_FUNC_CIPHER_GET_PARAMS, \
271 (void (*)(void))aes_##kbits##_##lcmode##_get_params }, \
272 { OSSL_FUNC_CIPHER_GETTABLE_PARAMS, \
273 (void (*)(void))ossl_cipher_generic_gettable_params }, \
274 { OSSL_FUNC_CIPHER_GET_CTX_PARAMS, \
275 (void (*)(void))ossl_cipher_generic_get_ctx_params }, \
276 { OSSL_FUNC_CIPHER_GETTABLE_CTX_PARAMS, \
277 (void (*)(void))ossl_cipher_generic_gettable_ctx_params }, \
278 { OSSL_FUNC_CIPHER_SET_CTX_PARAMS, \
279 (void (*)(void))aes_xts_set_ctx_params }, \
280 { OSSL_FUNC_CIPHER_SETTABLE_CTX_PARAMS, \
281 (void (*)(void))aes_xts_settable_ctx_params }, \
285 IMPLEMENT_cipher(xts, XTS, 256, AES_XTS_FLAGS);
286 IMPLEMENT_cipher(xts, XTS, 128, AES_XTS_FLAGS);