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authorLibravatar vnugent <public@vaughnnugent.com>2024-04-23 18:19:31 -0400
committerLibravatar vnugent <public@vaughnnugent.com>2024-04-23 18:19:31 -0400
commit7cb7a93de4f6f5e741bc5129e3d928e44f050930 (patch)
treeae5c564a0c3c60d0b4dac13ac8e8e3ebf7906ab1 /src/crypto
parent30e8dda6cbea86bdee6d5dfe48514385d3b9f81b (diff)
refactor!: MbedTLS on Windows, switch to uint32
Diffstat (limited to 'src/crypto')
-rw-r--r--src/crypto/impl/bcrypt.c295
-rw-r--r--src/crypto/impl/mbedtls.c170
-rw-r--r--src/crypto/impl/monocypher.c83
-rw-r--r--src/crypto/impl/openssl.c46
-rw-r--r--src/crypto/nc-crypto.c272
-rw-r--r--src/crypto/nc-crypto.h73
6 files changed, 939 insertions, 0 deletions
diff --git a/src/crypto/impl/bcrypt.c b/src/crypto/impl/bcrypt.c
new file mode 100644
index 0000000..970f68f
--- /dev/null
+++ b/src/crypto/impl/bcrypt.c
@@ -0,0 +1,295 @@
+/*
+* Copyright (c) 2024 Vaughn Nugent
+*
+* Package: noscrypt
+* File: impl/bcrypt.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 provides as many fallback implementations on Windows plaforms
+* as possible using the bcrypt library. This file should be included behind
+* other libarry implementations, as it is a fallback.
+*/
+
+#ifdef _NC_IS_WINDOWS
+
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h>
+#include <bcrypt.h>
+
+#include "nc-util.h"
+
+#define IF_BC_FAIL(x) if(!BCRYPT_SUCCESS(x))
+
+struct _bcrypt_ctx
+{
+ BCRYPT_ALG_HANDLE hAlg;
+ BCRYPT_HASH_HANDLE hHash;
+};
+
+_IMPLSTB NTSTATUS _bcInitSha256(struct _bcrypt_ctx* ctx, DWORD flags)
+{
+ NTSTATUS result;
+
+ result = BCryptOpenAlgorithmProvider(
+ &ctx->hAlg,
+ BCRYPT_SHA256_ALGORITHM,
+ NULL,
+ flags
+ );
+
+ /*
+ * If operation failed, ensure the algorithm handle is null
+ * to make free code easier to cleanup
+ */
+ if (!BCRYPT_SUCCESS(result))
+ {
+ ctx->hAlg = NULL;
+ }
+
+ return result;
+}
+
+_IMPLSTB NTSTATUS _bcCreateHmac(struct _bcrypt_ctx* ctx, const cspan_t* key)
+{
+ /*
+ * NOTE:
+ * I am not explicitly managing the hash object buffer. By setting
+ * the hash object to NULL, and length to 0, the buffer will be
+ * managed by the bcrypt library.
+ *
+ * See: https://learn.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptcreatehash
+ */
+
+ return BCryptCreateHash(
+ ctx->hAlg,
+ &ctx->hHash,
+ NULL,
+ 0,
+ (uint8_t*)key->data,
+ key->size,
+ BCRYPT_HASH_REUSABLE_FLAG /* Enable reusable for expand function */
+ );
+}
+
+_IMPLSTB NTSTATUS _bcCreate(struct _bcrypt_ctx* ctx)
+{
+ cspan_t key;
+
+ /* Zero out key span for 0 size and NULL data ptr */
+ SecureZeroMemory(&key, sizeof(cspan_t));
+
+ return _bcCreateHmac(ctx, &key);
+}
+
+_IMPLSTB NTSTATUS _bcHashDataRaw(const struct _bcrypt_ctx* ctx, const uint8_t* data, uint32_t len)
+{
+ return BCryptHashData(ctx->hHash, (uint8_t*)data, len, 0);
+}
+
+_IMPLSTB NTSTATUS _bcHashData(const struct _bcrypt_ctx* ctx, const cspan_t* data)
+{
+ return _bcHashDataRaw(ctx, data->data, data->size);
+}
+
+_IMPLSTB NTSTATUS _bcFinishHash(const struct _bcrypt_ctx* ctx, sha256_t digestOut32)
+{
+ return BCryptFinishHash(ctx->hHash, digestOut32, sizeof(sha256_t), 0);
+}
+
+_IMPLSTB void _bcDestroyCtx(struct _bcrypt_ctx* ctx)
+{
+ /* Free the hash memory if it was allocated */
+ if(ctx->hHash) BCryptDestroyHash(ctx->hHash);
+
+ /* Close the algorithm provider */
+ if (ctx->hAlg) BCryptCloseAlgorithmProvider(ctx->hAlg, 0);
+
+ ctx->hAlg = NULL;
+ ctx->hHash = NULL;
+}
+
+#ifndef _IMPL_SECURE_ZERO_MEMSET
+ /*
+ * On Windows, we can use SecureZeroMemory
+ * as platform zeroing function.
+ *
+ * NOTE:
+ * SecureZeroMemory2 uses volitle function argument
+ * pointers, which is a contested mehtod of compiler
+ * optimization prevention. GNU seems to oppose this method
+ *
+ * https://learn.microsoft.com/en-us/windows/win32/memory/winbase-securezeromemory2
+ */
+ #define _IMPL_SECURE_ZERO_MEMSET SecureZeroMemory
+#endif /* !_IMPL_SECURE_ZERO_MEMSET */
+
+/*
+* Provide win32 fallback for sha256 digest if needed
+*/
+
+#ifndef _IMPL_CRYPTO_SHA256_DIGEST
+
+ /* Export function fallack */
+ #define _IMPL_CRYPTO_SHA256_DIGEST _bcrypt_sha256_digest
+
+ _IMPLSTB cstatus_t _bcrypt_sha256_digest(const cspan_t* data, sha256_t digestOut32)
+ {
+ cstatus_t result;
+ struct _bcrypt_ctx ctx;
+
+ result = CSTATUS_FAIL; /* Start in fail state */
+
+ IF_BC_FAIL(_bcInitSha256(&ctx, 0)) goto Exit;
+
+ IF_BC_FAIL(_bcCreate(&ctx)) goto Exit;
+
+ IF_BC_FAIL(_bcHashData(&ctx, data)) goto Exit;
+
+ IF_BC_FAIL(_bcFinishHash(&ctx, digestOut32)) goto Exit;
+
+ result = CSTATUS_OK; /* Hash operation completed, so set success */
+
+ Exit:
+
+ _bcDestroyCtx(&ctx);
+
+ return result;
+ }
+
+#endif /* !_IMPL_CRYPTO_SHA256_DIGEST */
+
+#ifndef _IMPL_CRYPTO_SHA256_HMAC
+
+ /* Export function */
+ #define _IMPL_CRYPTO_SHA256_HMAC _bcrypt_hmac_sha256
+
+ _IMPLSTB cstatus_t _bcrypt_hmac_sha256(const cspan_t* key, const cspan_t* data, sha256_t hmacOut32)
+ {
+ cstatus_t result;
+ struct _bcrypt_ctx ctx;
+
+ result = CSTATUS_FAIL; /* Start in fail state */
+
+ /* Init context with hmac flag set */
+ IF_BC_FAIL(_bcInitSha256(&ctx, BCRYPT_ALG_HANDLE_HMAC_FLAG)) goto Exit;
+
+ IF_BC_FAIL(_bcCreateHmac(&ctx, key)) goto Exit;
+
+ IF_BC_FAIL(_bcHashData(&ctx, data)) goto Exit;
+
+ IF_BC_FAIL(_bcFinishHash(&ctx, hmacOut32)) goto Exit;
+
+ result = CSTATUS_OK; /* HMAC operation completed, so set success */
+
+ Exit:
+
+ _bcDestroyCtx(&ctx);
+
+ return result;
+ }
+
+#endif /* !_IMPL_CRYPTO_SHA256_HMAC */
+
+/*
+* Provide a fallback HKDF expand function using the
+* HMAC function as a base.
+*/
+
+#ifndef _IMPL_CRYPTO_SHA256_HKDF_EXPAND
+
+ #define _IMPL_CRYPTO_SHA256_HKDF_EXPAND _bcrypt_fallback_hkdf_expand
+
+ /* Include string for memmove */
+ #include <string.h>
+
+ static void ncWriteSpanS(span_t* span, uint32_t offset, const uint8_t* data, uint32_t size)
+ {
+ DEBUG_ASSERT2(span != NULL, "Expected span to be non-null")
+ DEBUG_ASSERT2(data != NULL, "Expected data to be non-null")
+ DEBUG_ASSERT2(offset + size <= span->size, "Expected offset + size to be less than span size")
+
+ /* Copy data to span */
+ memmove(span->data + offset, data, size);
+ }
+
+ STATIC_ASSERT(HKDF_IN_BUF_SIZE > SHA256_DIGEST_SIZE, "HDK Buffer must be at least the size of the underlying hashing alg output")
+
+ /*
+ * The following functions implements the HKDF expand function using an existing
+ * HMAC function. This is a fallback implementation for Windows platforms at the moment.
+ *
+ * This follows the guidence from RFC 5869: https://tools.ietf.org/html/rfc5869
+ */
+
+ #define _BC_MIN(a, b) (a < b ? a : b)
+
+ _IMPLSTB cstatus_t _bcrypt_fallback_hkdf_expand(const cspan_t* prk, const cspan_t* info, span_t* okm)
+ {
+ cstatus_t result;
+ struct _bcrypt_ctx ctx;
+
+ uint8_t counter;
+ uint32_t tLen, okmOffset;
+ uint8_t t[HKDF_IN_BUF_SIZE];
+
+ _IMPL_SECURE_ZERO_MEMSET(t, sizeof(t));
+
+ tLen = 0; /* T(0) is an empty string(zero length) */
+ okmOffset = 0;
+ result = CSTATUS_FAIL; /* Start in fail state */
+
+ /* Init context with hmac flag set, it will be reused */
+ IF_BC_FAIL(_bcInitSha256(&ctx, BCRYPT_ALG_HANDLE_HMAC_FLAG)) goto Exit;
+
+ /* Set hmac key to the prk, alg is set to reusable */
+ IF_BC_FAIL(_bcCreateHmac(&ctx, prk)) goto Exit;
+
+ /* Compute T(N) = HMAC(prk, T(n-1) | info | n) */
+ for (counter = 1; okmOffset < okm->size; counter++)
+ {
+ IF_BC_FAIL(_bcHashDataRaw(&ctx, t, tLen)) goto Exit;
+ IF_BC_FAIL(_bcHashData(&ctx, info)) goto Exit;
+ IF_BC_FAIL(_bcHashDataRaw(&ctx, &counter, sizeof(counter))) goto Exit;
+
+ /* Write current hash state to t buffer */
+ IF_BC_FAIL(_bcFinishHash(&ctx, t)) goto Exit;
+
+ /* Set the length of the current hash state */
+ tLen = _BC_MIN(okm->size - okmOffset, SHA256_DIGEST_SIZE);
+
+ DEBUG_ASSERT(tLen <= sizeof(t));
+
+ /* write the T buffer back to okm */
+ ncWriteSpanS(okm, okmOffset, t, tLen);
+
+ /* shift base okm pointer by T */
+ okmOffset += tLen;
+ }
+
+ result = CSTATUS_OK; /* HMAC operation completed, so set success */
+
+ Exit:
+
+ _bcDestroyCtx(&ctx);
+
+ return result;
+ }
+
+#endif /* !_IMPL_CRYPTO_SHA256_HKDF_EXPAND */
+
+#endif /* _NC_IS_WINDOWS */ \ No newline at end of file
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 \ No newline at end of file
diff --git a/src/crypto/impl/monocypher.c b/src/crypto/impl/monocypher.c
new file mode 100644
index 0000000..790f5e9
--- /dev/null
+++ b/src/crypto/impl/monocypher.c
@@ -0,0 +1,83 @@
+/*
+* Copyright (c) 2024 Vaughn Nugent
+*
+* Package: noscrypt
+* File: impl/monocypher.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 handles some fallbacks that may not be available on
+* some platforms. More specifically:
+* - Secure memset 0
+* - Chacha20 cipher
+*
+*/
+
+#ifdef NC_ENABLE_MONOCYPHER
+
+#include <monocypher.h>
+
+#include "nc-util.h"
+
+/* Export secure memse0 */
+#ifndef _IMPL_SECURE_ZERO_MEMSET
+
+ /* export cytpo wipe function as is */
+ #define _IMPL_SECURE_ZERO_MEMSET crypto_wipe
+#endif
+
+/* Export Chacha20 */
+#ifndef _IMPL_CHACHA20_CRYPT
+
+ #define _IMPL_CHACHA20_CRYPT _mc_chacha20_crypt
+
+ _IMPLSTB cstatus_t _mc_chacha20_crypt(
+ const uint8_t* key,
+ const uint8_t* nonce,
+ const uint8_t* input,
+ uint8_t* output,
+ uint32_t dataLen
+ )
+ {
+ if(dataLen > SIZE_MAX)
+ {
+ return CSTATUS_FAIL;
+ }
+
+ /*
+ * Function returns the next counter value which is not
+ * needed for noscrypt as encryptions are one-shot, and
+ * require a new nonce for each encryption.
+ *
+ * ITEF function uses a 12byte nonce which is required for
+ * nip-44 compliant encryption.
+ */
+ crypto_chacha20_ietf(
+ output,
+ input,
+ (size_t)dataLen,
+ key,
+ nonce,
+ 0x00 /* Counter always starts at 0 */
+ );
+
+ return CSTATUS_OK;
+ }
+
+#endif
+
+#endif /* !NC_ENABLE_MONOCYPHER */ \ No newline at end of file
diff --git a/src/crypto/impl/openssl.c b/src/crypto/impl/openssl.c
new file mode 100644
index 0000000..1217e60
--- /dev/null
+++ b/src/crypto/impl/openssl.c
@@ -0,0 +1,46 @@
+/*
+* Copyright (c) 2024 Vaughn Nugent
+*
+* Package: noscrypt
+* File: impl/openssl.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/.
+*/
+
+
+/* Setup openssl */
+
+#ifdef OPENSSL_CRYPTO_LIB
+
+#include <openssl/sha.h>
+
+#include "nc-util.h"
+
+/*
+* EXPORT SUPPORTED FUNCTIONS AS MACROS
+*/
+#define _IMPL_CHACHA20_CRYPT _mbed_chacha20_encrypt
+#define _IMPL_CRYPTO_SHA256_HMAC _mbed_sha256_hmac
+#define _IMPL_CRYPTO_SHA256_DIGEST _ossl_sha256_digest
+#define _IMPL_CRYPTO_FIXED_TIME_COMPARE _mbed_fixed_time_compare
+#define _IMPL_CRYPTO_SHA256_HKDF_EXPAND _mbed_sha256_hkdf_expand
+#define _IMPL_CRYPTO_SHA256_HKDF_EXTRACT _mbed_sha256_hkdf_extract
+
+_IMPLSTB int _ossl_sha256_digest(const uint8_t* data, uint8_t* digest)
+{
+
+}
+
+
+#endif /*!OPENSSL_CRYPTO_LIB */ \ No newline at end of file
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);
+}
diff --git a/src/crypto/nc-crypto.h b/src/crypto/nc-crypto.h
new file mode 100644
index 0000000..64d4ad8
--- /dev/null
+++ b/src/crypto/nc-crypto.h
@@ -0,0 +1,73 @@
+
+/*
+* Copyright (c) 2024 Vaughn Nugent
+*
+* Package: noscrypt
+* File: nc-crypto.h
+*
+* 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/.
+*/
+
+#pragma once
+
+#ifndef _NC_CRYPTO_H
+#define _NC_CRYPTO_H
+
+#include <stdint.h>
+
+#define CHACHA_NONCE_SIZE 0x0cu /* Size of 12 is set by the cipher spec */
+#define CHACHA_KEY_SIZE 0x20u /* Size of 32 is set by the cipher spec */
+#define SHA256_DIGEST_SIZE 0x20u /* Size of 32 is set by the cipher spec */
+
+typedef uint8_t cstatus_t;
+#define CSTATUS_OK ((cstatus_t)0x01u)
+#define CSTATUS_FAIL ((cstatus_t)0x00u)
+
+typedef uint8_t sha256_t[SHA256_DIGEST_SIZE];
+
+/*
+* IMPORTANT:
+* The HKDF_IN_BUF_SIZE defintion sets the internal stack buffer size to use
+* during fallback HKDF_Expand operations.
+*
+* 128 bytes should be more than enough for most use cases, without going
+* overboard. Could be dialed in better for specific use cases later.
+*/
+
+#ifndef HKDF_IN_BUF_SIZE
+ #define HKDF_IN_BUF_SIZE 0x80
+#endif
+
+
+uint32_t ncCryptoFixedTimeComp(const uint8_t* a, const uint8_t* b, uint32_t size);
+
+void ncCryptoSecureZero(void* ptr, uint32_t size);
+
+cstatus_t ncCryptoDigestSha256(const cspan_t* data, sha256_t digestOut32);
+
+cstatus_t ncCryptoHmacSha256(const cspan_t* key, const cspan_t* data, sha256_t hmacOut32);
+
+cstatus_t ncCryptoSha256HkdfExpand(const cspan_t* prk, const cspan_t* info, span_t* okm);
+
+cstatus_t ncCryptoSha256HkdfExtract(const cspan_t* salt, const cspan_t* ikm, sha256_t 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
+);
+
+#endif /* !_NC_CRYPTO_H */