--- /dev/null
+/*
+ * Copyright 2019 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 "cipher_aes_xts.h"
+#include "internal/provider_algs.h"
+#include "internal/providercommonerr.h"
+
+/* TODO (3.0) Figure out what flags need to be set */
+#define AES_XTS_FLAGS (EVP_CIPH_FLAG_DEFAULT_ASN1 | EVP_CIPH_CUSTOM_IV \
+ | EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CTRL_INIT \
+ | EVP_CIPH_CUSTOM_COPY)
+
+#define AES_XTS_IV_BITS 128
+#define AES_XTS_BLOCK_BITS 8
+
+#ifdef FIPS_MODE
+static const int allow_insecure_decrypt = 0;
+#else
+static const int allow_insecure_decrypt = 1;
+#endif /* FIPS_MODE */
+
+/* forward declarations */
+static OSSL_OP_cipher_encrypt_init_fn aes_xts_einit;
+static OSSL_OP_cipher_decrypt_init_fn aes_xts_dinit;
+static OSSL_OP_cipher_update_fn aes_xts_stream_update;
+static OSSL_OP_cipher_final_fn aes_xts_stream_final;
+static OSSL_OP_cipher_cipher_fn aes_xts_cipher;
+static OSSL_OP_cipher_freectx_fn aes_xts_freectx;
+static OSSL_OP_cipher_dupctx_fn aes_xts_dupctx;
+static OSSL_OP_cipher_set_ctx_params_fn aes_xts_set_ctx_params;
+static OSSL_OP_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 ((!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, int enc)
+{
+ PROV_AES_XTS_CTX *xctx = (PROV_AES_XTS_CTX *)vctx;
+ PROV_CIPHER_CTX *ctx = &xctx->base;
+
+ ctx->enc = enc;
+
+ if (iv != NULL) {
+ if (ivlen != ctx->ivlen) {
+ ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
+ return 0;
+ }
+ memcpy(ctx->iv, iv, ivlen);
+ xctx->iv_set = 1;
+ }
+ 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;
+ return ctx->hw->init(ctx, key, keylen);
+ }
+ return 1;
+}
+
+static int aes_xts_einit(void *vctx, const unsigned char *key, size_t keylen,
+ const unsigned char *iv, size_t ivlen)
+{
+ return aes_xts_init(vctx, key, keylen, iv, ivlen, 1);
+}
+
+static int aes_xts_dinit(void *vctx, const unsigned char *key, size_t keylen,
+ const unsigned char *iv, size_t ivlen)
+{
+ return aes_xts_init(vctx, key, keylen, iv, ivlen, 0);
+}
+
+static void *aes_xts_newctx(void *provctx, unsigned int mode, size_t kbits,
+ size_t blkbits, size_t ivbits)
+{
+ PROV_AES_XTS_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
+
+ if (ctx != NULL) {
+ cipher_generic_initkey(&ctx->base, kbits, blkbits, ivbits, mode,
+ 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;
+
+ 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 (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;
+ }
+ *ret = *in;
+ 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 (ctx->xts.key1 == NULL
+ || ctx->xts.key2 == NULL
+ || !ctx->iv_set
+ || out == NULL
+ || in == NULL
+ || inl < AES_BLOCK_SIZE)
+ return 0;
+
+ /*
+ * Impose a limit of 2^20 blocks per data unit as specifed 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;
+ return 1;
+
+ *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;
+ }
+
+ *outl = inl;
+ return 1;
+}
+
+static int aes_xts_stream_final(void *vctx, unsigned char *out, size_t *outl,
+ size_t outsize)
+{
+ *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(void)
+{
+ 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;
+
+ /*
+ * TODO(3.0) We need a general solution for handling missing parameters
+ * inside set_params and get_params methods.
+ */
+ 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_OP_cipher_get_params_fn aes_##kbits##_##lcmode##_get_params; \
+static int aes_##kbits##_##lcmode##_get_params(OSSL_PARAM params[]) \
+{ \
+ return cipher_generic_get_params(params, EVP_CIPH_##UCMODE##_MODE, \
+ flags, 2 * kbits, AES_XTS_BLOCK_BITS, \
+ AES_XTS_IV_BITS); \
+} \
+static OSSL_OP_cipher_newctx_fn aes_##kbits##_xts_newctx; \
+static void *aes_##kbits##_xts_newctx(void *provctx) \
+{ \
+ return aes_xts_newctx(provctx, EVP_CIPH_##UCMODE##_MODE, 2 * kbits, \
+ AES_XTS_BLOCK_BITS, AES_XTS_IV_BITS); \
+} \
+const OSSL_DISPATCH 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))cipher_generic_gettable_params }, \
+ { OSSL_FUNC_CIPHER_GET_CTX_PARAMS, \
+ (void (*)(void))cipher_generic_get_ctx_params }, \
+ { OSSL_FUNC_CIPHER_GETTABLE_CTX_PARAMS, \
+ (void (*)(void))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);
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