wavestone-cdt-edrsandblast/EDRSandblast/Utils/HttpClient.c

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
#include <windef.h>
#include <winhttp.h>

#include "../EDRSandblast.h"
#include "HttpClient.h"


BOOL HttpsDownloadFullFile(LPCWSTR domain, LPCWSTR uri, PBYTE* output, SIZE_T* output_size) {
	///wprintf_or_not(L"Downloading https://%s%s...\n", domain, uri);
	// Get proxy configuration
	WINHTTP_CURRENT_USER_IE_PROXY_CONFIG proxyConfig;
	WinHttpGetIEProxyConfigForCurrentUser(&proxyConfig);
	BOOL proxySet = !(proxyConfig.fAutoDetect || proxyConfig.lpszAutoConfigUrl != NULL);
	DWORD proxyAccessType = proxySet ? ((proxyConfig.lpszProxy == NULL) ?
		WINHTTP_ACCESS_TYPE_NO_PROXY : WINHTTP_ACCESS_TYPE_NAMED_PROXY) : WINHTTP_ACCESS_TYPE_NO_PROXY;
	LPCWSTR proxyName = proxySet ? proxyConfig.lpszProxy : WINHTTP_NO_PROXY_NAME;
	LPCWSTR proxyBypass = proxySet ? proxyConfig.lpszProxyBypass : WINHTTP_NO_PROXY_BYPASS;

	// Initialize HTTP session and request
	HINTERNET hSession = WinHttpOpen(L"WinHTTP/1.0", proxyAccessType, proxyName, proxyBypass, 0);
	if (hSession == NULL) {
		printf_or_not("WinHttpOpen failed with error : 0x%x\n", GetLastError());
		return FALSE;
	}
	HINTERNET hConnect = WinHttpConnect(hSession, domain, INTERNET_DEFAULT_HTTPS_PORT, 0);
	if (!hConnect) {
		printf_or_not("WinHttpConnect failed with error : 0x%x\n", GetLastError());
		return FALSE;
	}
	HINTERNET hRequest = WinHttpOpenRequest(hConnect, L"GET", uri, NULL,
		WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_SECURE);
	if (!hRequest) {
		return FALSE;
	}

	// Configure proxy manually
	if (!proxySet)
	{
		WINHTTP_AUTOPROXY_OPTIONS  autoProxyOptions;
		autoProxyOptions.dwFlags = proxyConfig.lpszAutoConfigUrl != NULL ? WINHTTP_AUTOPROXY_CONFIG_URL : WINHTTP_AUTOPROXY_AUTO_DETECT;
		autoProxyOptions.dwAutoDetectFlags = WINHTTP_AUTO_DETECT_TYPE_DHCP | WINHTTP_AUTO_DETECT_TYPE_DNS_A;
		autoProxyOptions.fAutoLogonIfChallenged = TRUE;

		if (proxyConfig.lpszAutoConfigUrl != NULL)
			autoProxyOptions.lpszAutoConfigUrl = proxyConfig.lpszAutoConfigUrl;

		WCHAR szUrl[MAX_PATH] = { 0 }; 
		swprintf_s(szUrl, _countof(szUrl), L"https://%ws%ws", domain, uri);

		WINHTTP_PROXY_INFO proxyInfo;
		WinHttpGetProxyForUrl(
			hSession,
			szUrl,
			&autoProxyOptions,
			&proxyInfo);

		WinHttpSetOption(hRequest, WINHTTP_OPTION_PROXY, &proxyInfo, sizeof(proxyInfo));
		DWORD logonPolicy = WINHTTP_AUTOLOGON_SECURITY_LEVEL_LOW;
		WinHttpSetOption(hRequest, WINHTTP_OPTION_AUTOLOGON_POLICY, &logonPolicy, sizeof(logonPolicy));
	}

	// Perform request
	BOOL bRequestSent;
	do {
		bRequestSent = WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, 0);
	}  while (!bRequestSent && GetLastError() == ERROR_WINHTTP_RESEND_REQUEST);
	if (!bRequestSent) {
		return FALSE;
	}
	BOOL bResponseReceived = WinHttpReceiveResponse(hRequest, NULL);
	if (!bResponseReceived) {
		return FALSE;
	}

	// Read response
	DWORD dwAvailableSize = 0;
	DWORD dwDownloadedSize = 0;
	SIZE_T allocatedSize = 4096;
	if (!WinHttpQueryDataAvailable(hRequest, &dwAvailableSize))
	{
		return FALSE;
	}
	*output = (PBYTE) malloc(allocatedSize);
	*output_size = 0;
	while (dwAvailableSize)
	{
		while (*output_size + dwAvailableSize > allocatedSize) {
			allocatedSize *= 2;
			PBYTE new_output = (PBYTE)realloc(*output, allocatedSize);
			if (new_output == NULL)
			{
				return FALSE;
			}
			*output = new_output;
		}
		if (!WinHttpReadData(hRequest, *output + *output_size, dwAvailableSize, &dwDownloadedSize))
		{
			return FALSE;
		}
		*output_size += dwDownloadedSize;

		WinHttpQueryDataAvailable(hRequest, &dwAvailableSize);
	}
	PBYTE new_output = (PBYTE)realloc(*output, *output_size);
	if (new_output == NULL)
	{
		return FALSE;
	}
	*output = new_output;
	WinHttpCloseHandle(hRequest);
	WinHttpCloseHandle(hConnect);
	WinHttpCloseHandle(hSession);
	return TRUE;
}