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-rw-r--r--src/crypto/impl/bcrypt.c263
1 files changed, 263 insertions, 0 deletions
diff --git a/src/crypto/impl/bcrypt.c b/src/crypto/impl/bcrypt.c
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+/*
+* 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"
+#include "hkdf.h"
+
+#define IF_BC_FAIL(x) if(!BCRYPT_SUCCESS(x))
+#define BC_FAIL(x) if(!BCRYPT_SUCCESS(x)) return CSTATUS_FAIL;
+
+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 update object buffer. By setting
+ * the update 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 update 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
+
+ cstatus_t _bcrypt_hkdf_update(void* ctx, const cspan_t* data)
+ {
+ DEBUG_ASSERT(ctx != NULL)
+
+ BC_FAIL(_bcHashData((struct _bcrypt_ctx*)ctx, data))
+ return CSTATUS_OK;
+ }
+
+ cstatus_t _bcrypt_hkdf_finish(void* ctx, sha256_t hmacOut32)
+ {
+ DEBUG_ASSERT(ctx != NULL)
+
+ BC_FAIL(_bcFinishHash((struct _bcrypt_ctx*)ctx, hmacOut32))
+ return CSTATUS_OK;
+ }
+
+ _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;
+ struct nc_hkdf_fn_cb_struct handler;
+
+ handler.update = _bcrypt_hkdf_update;
+ handler.finish = _bcrypt_hkdf_finish;
+
+ /* Init bcrypt */
+ BC_FAIL(_bcInitSha256(&ctx, BCRYPT_ALG_HANDLE_HMAC_FLAG))
+
+ BC_FAIL(_bcCreateHmac(&ctx, prk))
+
+ /*
+ * NOTE! Hmac reusable flag must be set to allow for multiple
+ * calls to the finish function without losing the context.
+ */
+
+ result = hkdfExpandProcess(&handler, &ctx, info, okm);
+
+ _bcDestroyCtx(&ctx);
+
+ return result;
+ }
+
+#endif /* !_IMPL_CRYPTO_SHA256_HKDF_EXPAND */
+
+#endif /* _NC_IS_WINDOWS */ \ No newline at end of file