refactor!: MbedTLS on Windows, switch to uint32

1 files changed, 272 insertions, 0 deletions

diff --git a/src/crypto/nc-crypto.c b/src/crypto/nc-crypto.c
new file mode 100644
index 0000000..fb2c0da
--- /dev/null
+++ b/src/crypto/nc-crypto.c
@@ -0,0 +1,272 @@
+/*
+* Copyright (c) 2024 Vaughn Nugent
+*
+* Package: noscrypt
+* File: nc-crypto.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/.
+*/
+
+#include "nc-util.h"
+#include "nc-crypto.h"
+
+/*
+*  Functions are not forced inline, just suggested.
+*  So unless it beomes a performance issue, I will leave
+*  most/all impl functions inline and let the compiler 
+*  decide.
+*/
+
+#define _IMPLSTB static _nc_fn_inline
+
+/*
+* Impl .c files may define the following macros for function implementations:
+* 
+*		_IMPL_SECURE_ZERO_MEMSET			secure memset 0 function
+*		_IMPL_CHACHA20_CRYPT				chacha20 cipher function
+*		_IMPL_CRYPTO_FIXED_TIME_COMPARE		fixed time compare function
+*		_IMPL_CRYPTO_SHA256_HMAC			sha256 hmac function
+*		_IMPL_CRYPTO_SHA256_DIGEST			standard sha256 digest function
+* 		_IMPL_CRYPTO_SHA256_HKDF_EXPAND		hkdf expand function
+* 		_IMPL_CRYPTO_SHA256_HKDF_EXTRACT	hkdf extract function
+* 
+* Macros are used to allow the preprocessor to select the correct implementation
+* or raise errors if no implementation is defined.
+*/
+
+
+
+/*
+* Prioritize embedded builds with mbedtls
+*/
+#include "impl/mbedtls.c"
+
+/*
+* Include openssl as an alternative default 
+* implementation
+*/
+#include "impl/openssl.c"
+
+/*
+* Include win32 platform specific fallback support 
+* using bcrypt.
+*/
+#include "impl/bcrypt.c"
+
+/*
+* Handle default implementations of secure 
+* memset 0 functions for each platform.
+*/
+#ifndef _IMPL_SECURE_ZERO_MEMSET
+	#if defined(__GNUC__)	
+		/*
+		*	When using libc, we can use explicit_bzero
+		*	as secure memset implementation.
+		* 
+		*	https://sourceware.org/glibc/manual/2.39/html_mono/libc.html#Erasing-Sensitive-Data
+		*/
+		#include <string.h>
+		#define _IMPL_SECURE_ZERO_MEMSET explicit_bzero
+	#endif
+#endif
+
+/*
+* Finally fall back to monocipher to handle some
+* that are not provided by other libraries.
+*
+* Platform specific opimizations are considered
+* "better" than monocypher options, so this is
+* added as a last resort. Momocypher is "correct"
+* and portable, but not optimized for any specific
+* platform.
+*/
+#include "impl/monocypher.c"
+
+
+#ifdef _IMPL_CRYPTO_SHA256_HMAC
+
+	/*
+	* If a library does not provide a HKDF extract function,
+	* we can just use the HMAC function as a fallback.
+	*
+	* This is a fallback because another library may provide
+	* a more optimized implementation.
+	*/
+
+	#ifndef _IMPL_CRYPTO_SHA256_HKDF_EXTRACT 
+
+		#define _IMPL_CRYPTO_SHA256_HKDF_EXTRACT		_fallbackHkdfExtract
+
+		_IMPLSTB cstatus_t _fallbackHkdfExtract(const cspan_t* salt, const cspan_t* ikm, sha256_t prk)
+		{
+			return _IMPL_CRYPTO_SHA256_HMAC(salt, ikm, prk);
+		}
+
+	#endif /* !_IMPL_CRYPTO_SHA256_HKDF_EXTRACT */
+	
+#endif /* _IMPL_CRYPTO_SHA256_HMAC */
+
+/* Fallback for fixed time comparison for all platforms */
+#ifndef _IMPL_CRYPTO_FIXED_TIME_COMPARE
+
+	#pragma message("Warning: No fixed time compare implementation defined, using fallback. This may not be secure on all platforms")
+
+	#define _IMPL_CRYPTO_FIXED_TIME_COMPARE	_fallbackFixedTimeCompare
+
+	/*
+	* This implemntation is a slightly simplified version of 
+	* MBed TLS constant time memcmp function, knowm to be a 32bit 
+	* integer size
+	*/
+
+	static uint32_t _fallbackFixedTimeCompare(const uint8_t* a, const uint8_t* b, uint32_t size)
+	{
+		size_t i;
+		uint32_t result;
+		uint8_t O;
+		volatile const uint8_t* A, * B;		
+
+		result = 0;
+		O = 0;
+		A = (volatile const uint8_t*)a;
+		B = (volatile const uint8_t*)b;
+
+		/* Compare each byte */
+		for(i = 0; i < size; i++)
+		{
+			/* Handle volatile read */
+			O |= (A[i] ^ B[i]);
+
+			result |= O;
+		}
+
+		return result;
+	}
+
+#endif /* !_IMPL_CRYPTO_FIXED_TIME_COMPARE */
+
+
+/*
+* Internal function implementations that perform
+* basic checking and call the correct implementation
+* for the desired crypto impl.
+*/
+
+void ncCryptoSecureZero(void* ptr, uint32_t size)
+{
+	DEBUG_ASSERT2(ptr != NULL, "Expected ptr to be non-null")
+
+#ifndef _IMPL_SECURE_ZERO_MEMSET
+	#error "No secure memset implementation defined"
+#endif /* _IMPL_SECURE_ZERO_MEMSET */
+
+	_IMPL_SECURE_ZERO_MEMSET(ptr, size);
+}
+
+uint32_t ncCryptoFixedTimeComp(const uint8_t* a, const uint8_t* b, uint32_t size)
+{
+	DEBUG_ASSERT2(a != NULL, "Expected a to be non-null")
+	DEBUG_ASSERT2(b != NULL, "Expected b to be non-null")
+
+#ifndef _IMPL_CRYPTO_FIXED_TIME_COMPARE
+	#error "No fixed time compare implementation defined"
+#endif /* !_IMPL_CRYPTO_FIXED_TIME_COMPARE */
+
+	return _IMPL_CRYPTO_FIXED_TIME_COMPARE(a, b, size);
+}
+
+cstatus_t ncCryptoDigestSha256(const cspan_t* data, sha256_t digestOut32)
+{
+	/* Debug arg validate */
+	DEBUG_ASSERT2(data != NULL && data->data != NULL,	"Expected data to be non-null")
+	DEBUG_ASSERT2(digestOut32 != NULL,					"Expected digestOut32 to be non-null")
+
+#ifndef _IMPL_CRYPTO_SHA256_DIGEST
+	#error "No SHA256 implementation defined"
+#endif /* !_IMPL_CRYPTO_SHA256_DIGEST */
+
+	return _IMPL_CRYPTO_SHA256_DIGEST(data, digestOut32);
+}
+
+cstatus_t ncCryptoHmacSha256(const cspan_t* key, const cspan_t* data, sha256_t hmacOut32)
+{
+	/* Debug arg validate */
+	DEBUG_ASSERT2(key != NULL && key->data != NULL,			"Expected key to be non-null")
+	DEBUG_ASSERT2(data != NULL && data->data != NULL,		"Expected data to be non-null")
+	DEBUG_ASSERT2(hmacOut32 != NULL && data->data != NULL,	"Expected hmacOut32 to be non-null")
+
+#ifndef _IMPL_CRYPTO_SHA256_HMAC
+	#error "No SHA256 HMAC implementation defined"
+#endif /* !_IMPL_CRYPTO_SHA256_HMAC */
+
+	return _IMPL_CRYPTO_SHA256_HMAC(key, data, hmacOut32);
+}
+
+cstatus_t ncCryptoSha256HkdfExpand(const cspan_t* prk, const cspan_t* info, span_t* okm)
+{
+	/* Debug arg validate */
+	DEBUG_ASSERT2(prk != NULL && prk->data != NULL,		"Expected prk to be non-null")
+	DEBUG_ASSERT2(info != NULL && info->data != NULL,	"Expected info to be non-null")
+	DEBUG_ASSERT2(okm != NULL && okm->data != NULL,		"Expected okm to be non-null")
+
+	/*
+	* RFC 5869: 2.3
+	* "length of output keying material in octets (<= 255 * HashLen)"
+	*/
+
+	if(okm->size > (uint32_t)(0xFFu * SHA256_DIGEST_SIZE))
+	{
+		return CSTATUS_FAIL;
+	}
+
+#ifndef _IMPL_CRYPTO_SHA256_HKDF_EXPAND
+	#error "No SHA256 HKDF expand implementation defined"
+#endif /* !_IMPL_CRYPTO_SHA256_HKDF_EXPAND */
+	
+	return _IMPL_CRYPTO_SHA256_HKDF_EXPAND(prk, info, okm);
+}
+
+cstatus_t ncCryptoSha256HkdfExtract(const cspan_t* salt, const cspan_t* ikm, sha256_t prk)
+{
+	/* Debug arg validate */
+	DEBUG_ASSERT2(salt != NULL, "Expected salt to be non-null")
+	DEBUG_ASSERT2(ikm  != NULL, "Expected ikm to be non-null")
+	DEBUG_ASSERT2(prk  != NULL, "Expected prk to be non-null")
+
+#ifndef _IMPL_CRYPTO_SHA256_HKDF_EXTRACT
+	#error "No SHA256 HKDF extract implementation defined"
+#endif /* !_IMPL_CRYPTO_SHA256_HKDF_EXTRACT */
+	
+	return _IMPL_CRYPTO_SHA256_HKDF_EXTRACT(salt, ikm, prk);
+}
+
+cstatus_t ncCryptoChacha20(
+	const uint8_t key[CHACHA_KEY_SIZE],
+	const uint8_t nonce[CHACHA_NONCE_SIZE],
+	const uint8_t* input,
+	uint8_t* output,
+	uint32_t dataSize
+)
+{
+	DEBUG_ASSERT2(key != NULL,		"Expected key to be non-null")
+	DEBUG_ASSERT2(nonce != NULL,	"Expected nonce to be non-null")
+	DEBUG_ASSERT2(input != NULL,	"Expected input to be non-null")
+	DEBUG_ASSERT2(output != NULL,	"Expected output to be non-null")
+
+#ifndef _IMPL_CHACHA20_CRYPT
+	#error "No chacha20 implementation defined"
+#endif /* !_IMPL_CHACHA20_CRYPT */
+
+	return _IMPL_CHACHA20_CRYPT(key, nonce, input, output, dataSize);
+}