refactor!: MbedTLS on Windows, switch to uint32

1 files changed, 170 insertions, 0 deletions

diff --git a/src/crypto/impl/mbedtls.c b/src/crypto/impl/mbedtls.c
new file mode 100644
index 0000000..ae36bbd
--- /dev/null
+++ b/src/crypto/impl/mbedtls.c
@@ -0,0 +1,170 @@
+/*
+* Copyright (c) 2024 Vaughn Nugent
+*
+* Package: noscrypt
+* File: mbedtls.c
+*
+* This library is free software; you can redistribute it and/or
+* modify it under the terms of the GNU Lesser General Public License
+* as published by the Free Software Foundation; either version 2.1
+* of the License, or  (at your option) any later version.
+*
+* This library is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+* Lesser General Public License for more details.
+*
+* You should have received a copy of the GNU Lesser General Public License
+* along with noscrypt. If not, see http://www.gnu.org/licenses/.
+*/
+
+
+/*
+* This file contains implemntation functions for the required 
+* cryptography primitives of noscrypt. This file stubs functionality
+* using the Mbed-TLS library, if the builder desires to link against
+* it. 
+*/
+
+#ifdef MBEDTLS_CRYPTO_LIB
+
+#include <mbedtls/md.h>
+#include <mbedtls/hkdf.h>
+#include <mbedtls/hmac_drbg.h>
+#include <mbedtls/sha256.h>
+#include <mbedtls/chacha20.h>
+#include <mbedtls/constant_time.h>
+
+#include "nc-util.h"
+
+/*
+*		EXPORT SUPPORTED FUNCTION OVERRIDES
+*/	
+
+_IMPLSTB const mbedtls_md_info_t* _mbed_sha256_alg(void)
+{
+	const mbedtls_md_info_t* info;
+	/* Get sha256 md info for hdkf operations */
+	info = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
+	DEBUG_ASSERT2(info != NULL, "Expected SHA256 md info pointer to be valid")
+	return info;
+}
+
+#if SIZE_MAX < UINT64_MAX
+	#define _ssize_guard(x) if(x > SIZE_MAX) return CSTATUS_FAIL;
+	#define _ssize_guard_int(x) if(x > SIZE_MAX) return 1;
+#else
+	#define _ssize_guard(x)
+	#define _ssize_guard_int(x)
+#endif
+
+#ifndef _IMPL_CHACHA20_CRYPT
+	
+	/* Export chacha20 computation */
+	#define _IMPL_CHACHA20_CRYPT _mbed_chacha20_encrypt	
+
+	_IMPLSTB cstatus_t _mbed_chacha20_encrypt(
+		const uint8_t* key,
+		const uint8_t* nonce,
+		const uint8_t* input,
+		uint8_t* output,
+		uint32_t dataLen
+	)
+	{
+		_ssize_guard(dataLen)
+
+		/* Counter always starts at 0 */
+		return mbedtls_chacha20_crypt(
+			key, 
+			nonce, 
+			0x00u,		/* nip-44 counter version */
+			dataLen, 
+			input, 
+			output
+		) == 0 ? CSTATUS_OK : CSTATUS_FAIL;
+	}
+
+#endif
+
+/* Export sha256 if not already defined */
+#ifndef _IMPL_CRYPTO_SHA256_DIGEST	
+	
+	#define _IMPL_CRYPTO_SHA256_DIGEST			_mbed_sha256_digest	
+
+	_IMPLSTB cstatus_t _mbed_sha256_digest(const cspan_t* data, sha256_t digestOut32)
+	{
+		_ssize_guard(data->size)
+
+		return mbedtls_sha256(
+			data->data, 
+			data->size, 
+			digestOut32, 
+			0				/* Set 0 for sha256 mode */
+		) == 0 ? CSTATUS_OK : CSTATUS_FAIL;
+	}
+
+#endif
+
+/* Export Sha256 hmac if not already defined by other libs */
+#ifndef _IMPL_CRYPTO_SHA256_HMAC
+
+	#define _IMPL_CRYPTO_SHA256_HMAC			_mbed_sha256_hmac
+
+	_IMPLSTB cstatus_t _mbed_sha256_hmac(const cspan_t* key, const cspan_t* data, sha256_t hmacOut32)
+	{
+		_ssize_guard(data->size)
+
+		/* Keys should never be large enough for this to matter, but sanity check. */
+		DEBUG_ASSERT2(key->size < SIZE_MAX, "Expected key size to be less than SIZE_MAX")
+
+		return mbedtls_md_hmac(
+			_mbed_sha256_alg(),
+			key->data, 
+			key->size,
+			data->data, 
+			data->size,
+			hmacOut32
+		) == 0 ? CSTATUS_OK : CSTATUS_FAIL;
+	}
+#endif
+
+/* Export hkdf expand if not already defined */
+#ifndef _IMPL_CRYPTO_SHA256_HKDF_EXPAND
+
+	#define _IMPL_CRYPTO_SHA256_HKDF_EXPAND		_mbed_sha256_hkdf_expand
+
+	_IMPLSTB cstatus_t _mbed_sha256_hkdf_expand(const cspan_t* prk, const cspan_t* info, span_t* okm)
+	{
+		/* These sizes should never be large enough to overflow on <64bit platforms, but sanity check */
+		DEBUG_ASSERT(okm->size < SIZE_MAX)
+		DEBUG_ASSERT(prk->size < SIZE_MAX)
+		DEBUG_ASSERT(info->size < SIZE_MAX)
+
+		return mbedtls_hkdf_expand(
+			_mbed_sha256_alg(),
+			prk->data, 
+			prk->size,
+			info->data, 
+			info->size,
+			okm->data, 
+			okm->size
+		) == 0 ? CSTATUS_OK : CSTATUS_FAIL;
+	}
+
+#endif
+
+/* Export fixed-time compare if not already defined */
+#ifndef _IMPL_CRYPTO_FIXED_TIME_COMPARE
+
+	#define _IMPL_CRYPTO_FIXED_TIME_COMPARE		_mbed_fixed_time_compare
+
+	/* fixed-time memcmp */
+	_IMPLSTB uint32_t _mbed_fixed_time_compare(const uint8_t* a, const uint8_t* b, uint32_t size)
+	{
+		_ssize_guard_int(size)
+
+		return (uint32_t)mbedtls_ct_memcmp(a, b, size);
+	}
+#endif
+
+#endif
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