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 ((!ossl_aes_xts_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,
70 const OSSL_PARAM params[], int enc)
72 PROV_AES_XTS_CTX *xctx = (PROV_AES_XTS_CTX *)vctx;
73 PROV_CIPHER_CTX *ctx = &xctx->base;
75 if (!ossl_prov_is_running())
81 if (!ossl_cipher_generic_initiv(vctx, iv, ivlen))
85 if (keylen != ctx->keylen) {
86 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
89 if (!aes_xts_check_keys_differ(key, keylen / 2, enc))
91 if (!ctx->hw->init(ctx, key, keylen))
94 return aes_xts_set_ctx_params(ctx, params);
97 static int aes_xts_einit(void *vctx, const unsigned char *key, size_t keylen,
98 const unsigned char *iv, size_t ivlen,
99 const OSSL_PARAM params[])
101 return aes_xts_init(vctx, key, keylen, iv, ivlen, params, 1);
104 static int aes_xts_dinit(void *vctx, const unsigned char *key, size_t keylen,
105 const unsigned char *iv, size_t ivlen,
106 const OSSL_PARAM params[])
108 return aes_xts_init(vctx, key, keylen, iv, ivlen, params, 0);
111 static void *aes_xts_newctx(void *provctx, unsigned int mode, uint64_t flags,
112 size_t kbits, size_t blkbits, size_t ivbits)
114 PROV_AES_XTS_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
117 ossl_cipher_generic_initkey(&ctx->base, kbits, blkbits, ivbits, mode,
118 flags, ossl_prov_cipher_hw_aes_xts(kbits),
124 static void aes_xts_freectx(void *vctx)
126 PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
128 ossl_cipher_generic_reset_ctx((PROV_CIPHER_CTX *)vctx);
129 OPENSSL_clear_free(ctx, sizeof(*ctx));
132 static void *aes_xts_dupctx(void *vctx)
134 PROV_AES_XTS_CTX *in = (PROV_AES_XTS_CTX *)vctx;
135 PROV_AES_XTS_CTX *ret = NULL;
137 if (!ossl_prov_is_running())
140 if (in->xts.key1 != NULL) {
141 if (in->xts.key1 != &in->ks1)
144 if (in->xts.key2 != NULL) {
145 if (in->xts.key2 != &in->ks2)
148 ret = OPENSSL_malloc(sizeof(*ret));
151 in->base.hw->copyctx(&ret->base, &in->base);
155 static int aes_xts_cipher(void *vctx, unsigned char *out, size_t *outl,
156 size_t outsize, const unsigned char *in, size_t inl)
158 PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
160 if (!ossl_prov_is_running()
161 || ctx->xts.key1 == NULL
162 || ctx->xts.key2 == NULL
166 || inl < AES_BLOCK_SIZE)
170 * Impose a limit of 2^20 blocks per data unit as specified by
171 * IEEE Std 1619-2018. The earlier and obsolete IEEE Std 1619-2007
172 * indicated that this was a SHOULD NOT rather than a MUST NOT.
173 * NIST SP 800-38E mandates the same limit.
175 if (inl > XTS_MAX_BLOCKS_PER_DATA_UNIT * AES_BLOCK_SIZE) {
176 ERR_raise(ERR_LIB_PROV, PROV_R_XTS_DATA_UNIT_IS_TOO_LARGE);
180 if (ctx->stream != NULL)
181 (*ctx->stream)(in, out, inl, ctx->xts.key1, ctx->xts.key2, ctx->base.iv);
182 else if (CRYPTO_xts128_encrypt(&ctx->xts, ctx->base.iv, in, out, inl,
190 static int aes_xts_stream_update(void *vctx, unsigned char *out, size_t *outl,
191 size_t outsize, const unsigned char *in,
194 PROV_AES_XTS_CTX *ctx = (PROV_AES_XTS_CTX *)vctx;
197 ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
201 if (!aes_xts_cipher(ctx, out, outl, outsize, in, inl)) {
202 ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
209 static int aes_xts_stream_final(void *vctx, unsigned char *out, size_t *outl,
212 if (!ossl_prov_is_running())
218 static const OSSL_PARAM aes_xts_known_settable_ctx_params[] = {
219 OSSL_PARAM_size_t(OSSL_CIPHER_PARAM_KEYLEN, NULL),
223 static const OSSL_PARAM *aes_xts_settable_ctx_params(ossl_unused void *cctx,
224 ossl_unused void *provctx)
226 return aes_xts_known_settable_ctx_params;
229 static int aes_xts_set_ctx_params(void *vctx, const OSSL_PARAM params[])
231 PROV_CIPHER_CTX *ctx = (PROV_CIPHER_CTX *)vctx;
237 p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_KEYLEN);
241 if (!OSSL_PARAM_get_size_t(p, &keylen)) {
242 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
245 /* The key length can not be modified for xts mode */
246 if (keylen != ctx->keylen)
253 #define IMPLEMENT_cipher(lcmode, UCMODE, kbits, flags) \
254 static OSSL_FUNC_cipher_get_params_fn aes_##kbits##_##lcmode##_get_params; \
255 static int aes_##kbits##_##lcmode##_get_params(OSSL_PARAM params[]) \
257 return ossl_cipher_generic_get_params(params, EVP_CIPH_##UCMODE##_MODE, \
258 flags, 2 * kbits, AES_XTS_BLOCK_BITS, \
261 static OSSL_FUNC_cipher_newctx_fn aes_##kbits##_xts_newctx; \
262 static void *aes_##kbits##_xts_newctx(void *provctx) \
264 return aes_xts_newctx(provctx, EVP_CIPH_##UCMODE##_MODE, flags, 2 * kbits, \
265 AES_XTS_BLOCK_BITS, AES_XTS_IV_BITS); \
267 const OSSL_DISPATCH ossl_aes##kbits##xts_functions[] = { \
268 { OSSL_FUNC_CIPHER_NEWCTX, (void (*)(void))aes_##kbits##_xts_newctx }, \
269 { OSSL_FUNC_CIPHER_ENCRYPT_INIT, (void (*)(void))aes_xts_einit }, \
270 { OSSL_FUNC_CIPHER_DECRYPT_INIT, (void (*)(void))aes_xts_dinit }, \
271 { OSSL_FUNC_CIPHER_UPDATE, (void (*)(void))aes_xts_stream_update }, \
272 { OSSL_FUNC_CIPHER_FINAL, (void (*)(void))aes_xts_stream_final }, \
273 { OSSL_FUNC_CIPHER_CIPHER, (void (*)(void))aes_xts_cipher }, \
274 { OSSL_FUNC_CIPHER_FREECTX, (void (*)(void))aes_xts_freectx }, \
275 { OSSL_FUNC_CIPHER_DUPCTX, (void (*)(void))aes_xts_dupctx }, \
276 { OSSL_FUNC_CIPHER_GET_PARAMS, \
277 (void (*)(void))aes_##kbits##_##lcmode##_get_params }, \
278 { OSSL_FUNC_CIPHER_GETTABLE_PARAMS, \
279 (void (*)(void))ossl_cipher_generic_gettable_params }, \
280 { OSSL_FUNC_CIPHER_GET_CTX_PARAMS, \
281 (void (*)(void))ossl_cipher_generic_get_ctx_params }, \
282 { OSSL_FUNC_CIPHER_GETTABLE_CTX_PARAMS, \
283 (void (*)(void))ossl_cipher_generic_gettable_ctx_params }, \
284 { OSSL_FUNC_CIPHER_SET_CTX_PARAMS, \
285 (void (*)(void))aes_xts_set_ctx_params }, \
286 { OSSL_FUNC_CIPHER_SETTABLE_CTX_PARAMS, \
287 (void (*)(void))aes_xts_settable_ctx_params }, \
291 IMPLEMENT_cipher(xts, XTS, 256, AES_XTS_FLAGS);
292 IMPLEMENT_cipher(xts, XTS, 128, AES_XTS_FLAGS);