/*

 * Copyright (C) the libgit2 contributors. All rights reserved.

 *

 * This file is part of libgit2, distributed under the GNU GPL v2 with

 * a Linking Exception. For full terms see the included COPYING file.

 */

#include "common.h"

#include "global.h"

#include "hash.h"

#include "hash/hash_win32.h"

#include <wincrypt.h>

#include <strsafe.h>

static struct git_hash_prov hash_prov = {0};

/* Hash initialization */

/* Initialize CNG, if available */

GIT_INLINE(int) hash_cng_prov_init(void)

{

	char dll_path[MAX_PATH];

	DWORD dll_path_len, size_len;

	/* Only use CNG on Windows 2008 / Vista SP1  or better (Windows 6.0 SP1) */

	if (!git_has_win32_version(6, 0, 1))

		return -1;

	/* Load bcrypt.dll explicitly from the system directory */

	if ((dll_path_len = GetSystemDirectory(dll_path, MAX_PATH)) == 0 ||

		dll_path_len > MAX_PATH ||

		StringCchCat(dll_path, MAX_PATH, "\\") < 0 ||

		StringCchCat(dll_path, MAX_PATH, GIT_HASH_CNG_DLL_NAME) < 0 ||

		(hash_prov.prov.cng.dll = LoadLibrary(dll_path)) == NULL)

		return -1;

	/* Load the function addresses */

	if ((hash_prov.prov.cng.open_algorithm_provider = (hash_win32_cng_open_algorithm_provider_fn)GetProcAddress(hash_prov.prov.cng.dll, "BCryptOpenAlgorithmProvider")) == NULL ||

		(hash_prov.prov.cng.get_property = (hash_win32_cng_get_property_fn)GetProcAddress(hash_prov.prov.cng.dll, "BCryptGetProperty")) == NULL ||

		(hash_prov.prov.cng.create_hash = (hash_win32_cng_create_hash_fn)GetProcAddress(hash_prov.prov.cng.dll, "BCryptCreateHash")) == NULL ||

		(hash_prov.prov.cng.finish_hash = (hash_win32_cng_finish_hash_fn)GetProcAddress(hash_prov.prov.cng.dll, "BCryptFinishHash")) == NULL ||

		(hash_prov.prov.cng.hash_data = (hash_win32_cng_hash_data_fn)GetProcAddress(hash_prov.prov.cng.dll, "BCryptHashData")) == NULL ||

		(hash_prov.prov.cng.destroy_hash = (hash_win32_cng_destroy_hash_fn)GetProcAddress(hash_prov.prov.cng.dll, "BCryptDestroyHash")) == NULL ||

		(hash_prov.prov.cng.close_algorithm_provider = (hash_win32_cng_close_algorithm_provider_fn)GetProcAddress(hash_prov.prov.cng.dll, "BCryptCloseAlgorithmProvider")) == NULL) {

		FreeLibrary(hash_prov.prov.cng.dll);

		return -1;

	}

	/* Load the SHA1 algorithm */

	if (hash_prov.prov.cng.open_algorithm_provider(&hash_prov.prov.cng.handle, GIT_HASH_CNG_HASH_TYPE, NULL, GIT_HASH_CNG_HASH_REUSABLE) < 0) {

		FreeLibrary(hash_prov.prov.cng.dll);

		return -1;

	}

	/* Get storage space for the hash object */

	if (hash_prov.prov.cng.get_property(hash_prov.prov.cng.handle, GIT_HASH_CNG_HASH_OBJECT_LEN, (PBYTE)&hash_prov.prov.cng.hash_object_size, sizeof(DWORD), &size_len, 0) < 0) {

		hash_prov.prov.cng.close_algorithm_provider(hash_prov.prov.cng.handle, 0);

		FreeLibrary(hash_prov.prov.cng.dll);

		return -1;

	}

	hash_prov.type = CNG;

	return 0;

}

GIT_INLINE(void) hash_cng_prov_shutdown(void)

{

	hash_prov.prov.cng.close_algorithm_provider(hash_prov.prov.cng.handle, 0);

	FreeLibrary(hash_prov.prov.cng.dll);

	hash_prov.type = INVALID;

}

/* Initialize CryptoAPI */

GIT_INLINE(int) hash_cryptoapi_prov_init()

{

	if (!CryptAcquireContext(&hash_prov.prov.cryptoapi.handle, NULL, 0, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))

		return -1;

	hash_prov.type = CRYPTOAPI;

	return 0;

}

GIT_INLINE(void) hash_cryptoapi_prov_shutdown(void)

{

	CryptReleaseContext(hash_prov.prov.cryptoapi.handle, 0);

	hash_prov.type = INVALID;

}

static void git_hash_global_shutdown(void)

{

	if (hash_prov.type == CNG)

		hash_cng_prov_shutdown();

	else if(hash_prov.type == CRYPTOAPI)

		hash_cryptoapi_prov_shutdown();

}

int git_hash_global_init(void)

{

	int error = 0;

	if (hash_prov.type != INVALID)

		return 0;

	if ((error = hash_cng_prov_init()) < 0)

		error = hash_cryptoapi_prov_init();

	git__on_shutdown(git_hash_global_shutdown);

	return error;

}

/* CryptoAPI: available in Windows XP and newer */

GIT_INLINE(int) hash_ctx_cryptoapi_init(git_hash_ctx *ctx)

{

	ctx->type = CRYPTOAPI;

	ctx->prov = &hash_prov;

	return git_hash_init(ctx);

}

GIT_INLINE(int) hash_cryptoapi_init(git_hash_ctx *ctx)

{

	if (ctx->ctx.cryptoapi.valid)

		CryptDestroyHash(ctx->ctx.cryptoapi.hash_handle);

	if (!CryptCreateHash(ctx->prov->prov.cryptoapi.handle, CALG_SHA1, 0, 0, &ctx->ctx.cryptoapi.hash_handle)) {

		ctx->ctx.cryptoapi.valid = 0;

		return -1;

	}

	ctx->ctx.cryptoapi.valid = 1;

	return 0;

}

GIT_INLINE(int) hash_cryptoapi_update(git_hash_ctx *ctx, const void *data, size_t len)

{

	assert(ctx->ctx.cryptoapi.valid);

	if (!CryptHashData(ctx->ctx.cryptoapi.hash_handle, (const BYTE *)data, (DWORD)len, 0))

		return -1;

	return 0;

}

GIT_INLINE(int) hash_cryptoapi_final(git_oid *out, git_hash_ctx *ctx)

{

	DWORD len = 20;

	int error = 0;

	assert(ctx->ctx.cryptoapi.valid);

	if (!CryptGetHashParam(ctx->ctx.cryptoapi.hash_handle, HP_HASHVAL, out->id, &len, 0))

		error = -1;

	CryptDestroyHash(ctx->ctx.cryptoapi.hash_handle);

	ctx->ctx.cryptoapi.valid = 0;

	return error;

}

GIT_INLINE(void) hash_ctx_cryptoapi_cleanup(git_hash_ctx *ctx)

{

	if (ctx->ctx.cryptoapi.valid)

		CryptDestroyHash(ctx->ctx.cryptoapi.hash_handle);

}

/* CNG: Available in Windows Server 2008 and newer */

GIT_INLINE(int) hash_ctx_cng_init(git_hash_ctx *ctx)

{

	if ((ctx->ctx.cng.hash_object = git__malloc(hash_prov.prov.cng.hash_object_size)) == NULL)

		return -1;

	if (hash_prov.prov.cng.create_hash(hash_prov.prov.cng.handle, &ctx->ctx.cng.hash_handle, ctx->ctx.cng.hash_object, hash_prov.prov.cng.hash_object_size, NULL, 0, 0) < 0) {

		git__free(ctx->ctx.cng.hash_object);

		return -1;

	}

	ctx->type = CNG;

	ctx->prov = &hash_prov;

	return 0;

}

GIT_INLINE(int) hash_cng_init(git_hash_ctx *ctx)

{

	BYTE hash[GIT_OID_RAWSZ];

	if (!ctx->ctx.cng.updated)

		return 0;

	/* CNG needs to be finished to restart */

	if (ctx->prov->prov.cng.finish_hash(ctx->ctx.cng.hash_handle, hash, GIT_OID_RAWSZ, 0) < 0)

		return -1;

	ctx->ctx.cng.updated = 0;

	return 0;

}

GIT_INLINE(int) hash_cng_update(git_hash_ctx *ctx, const void *data, size_t len)

{

	if (ctx->prov->prov.cng.hash_data(ctx->ctx.cng.hash_handle, (PBYTE)data, (ULONG)len, 0) < 0)

		return -1;

	return 0;

}

GIT_INLINE(int) hash_cng_final(git_oid *out, git_hash_ctx *ctx)

{

	if (ctx->prov->prov.cng.finish_hash(ctx->ctx.cng.hash_handle, out->id, GIT_OID_RAWSZ, 0) < 0)

		return -1;

	ctx->ctx.cng.updated = 0;

	return 0;

}

GIT_INLINE(void) hash_ctx_cng_cleanup(git_hash_ctx *ctx)

{

	ctx->prov->prov.cng.destroy_hash(ctx->ctx.cng.hash_handle);

	git__free(ctx->ctx.cng.hash_object);

}

/* Indirection between CryptoAPI and CNG */

int git_hash_ctx_init(git_hash_ctx *ctx)

{

	int error = 0;

	assert(ctx);

	/*

	 * When compiled with GIT_THREADS, the global hash_prov data is

	 * initialized with git_libgit2_init.  Otherwise, it must be initialized

	 * at first use.

	 */

	if (hash_prov.type == INVALID && (error = git_hash_global_init()) < 0)

		return error;

	memset(ctx, 0x0, sizeof(git_hash_ctx));

	return (hash_prov.type == CNG) ? hash_ctx_cng_init(ctx) : hash_ctx_cryptoapi_init(ctx);

}

int git_hash_init(git_hash_ctx *ctx)

{

	assert(ctx && ctx->type);

	return (ctx->type == CNG) ? hash_cng_init(ctx) : hash_cryptoapi_init(ctx);

}

int git_hash_update(git_hash_ctx *ctx, const void *data, size_t len)

{

	assert(ctx && ctx->type);

	return (ctx->type == CNG) ? hash_cng_update(ctx, data, len) : hash_cryptoapi_update(ctx, data, len);

}

int git_hash_final(git_oid *out, git_hash_ctx *ctx)

{

	assert(ctx && ctx->type);

	return (ctx->type == CNG) ? hash_cng_final(out, ctx) : hash_cryptoapi_final(out, ctx);

}

void git_hash_ctx_cleanup(git_hash_ctx *ctx)

{

	assert(ctx);

	if (ctx->type == CNG)

		hash_ctx_cng_cleanup(ctx);

	else if(ctx->type == CRYPTOAPI)

		hash_ctx_cryptoapi_cleanup(ctx);

}