Irvine( http://hp.vector.co.jp/authors/VA024591/ )でオレオレSSL(証明書エラーが出る)なサーバからファイルを引っ張ってくるためのWinInet.dllハック http://www.chiyoclone.net/ からlistexp2.exe拾ってきて、Win32のWinInet.dllラッパを作り、HttpOpenRequestAとHttpSendRequestAの処理を上書きする。

_ininet_ssl_f.c

#include <stdio.h>
#include <windows.h>
#include <WinInet.h>
#include "_ininet.h"

#define HINTERNET void*

EXTERN_C HINTERNET STDAPICALLTYPE d_HttpOpenRequestA(
    __in HINTERNET hConnect,
    __in_opt LPCSTR lpszVerb,
    __in_opt LPCSTR lpszObjectName,
    __in_opt LPCSTR lpszVersion,
    __in_opt LPCSTR lpszReferrer,
    __in_z_opt LPCSTR FAR * lplpszAcceptTypes,
    __in DWORD dwFlags,
    __in_opt DWORD_PTR dwContext
    )
{
  if(dwFlags & INTERNET_FLAG_SECURE){
		dwFlags |= INTERNET_FLAG_IGNORE_CERT_DATE_INVALID | INTERNET_FLAG_IGNORE_CERT_CN_INVALID;
	}

	return HttpOpenRequestA(hConnect,lpszVerb,lpszObjectName,lpszVersion,lpszReferrer,lplpszAcceptTypes,
		dwFlags,dwContext);
}

EXTERN_C BOOL STDAPICALLTYPE d_HttpSendRequestA(
  _In_  HINTERNET hRequest,
  _In_  LPCTSTR lpszHeaders,
  _In_  DWORD dwHeadersLength,
  _In_  LPVOID lpOptional,
  _In_  DWORD dwOptionalLength
)
{
	DWORD dwError;
	if(HttpSendRequest(hRequest,lpszHeaders,dwHeadersLength,lpOptional,dwOptionalLength))
		return TRUE;

	dwError = GetLastError();
	if(dwError == ERROR_INTERNET_INVALID_CA){
		DWORD dwFlags;
		DWORD dwBuffLen = sizeof(dwFlags);

		InternetQueryOption (hRequest, INTERNET_OPTION_SECURITY_FLAGS,(LPVOID)&dwFlags, &dwBuffLen);
		dwFlags |= SECURITY_FLAG_IGNORE_UNKNOWN_CA;
		InternetSetOption   (hRequest, INTERNET_OPTION_SECURITY_FLAGS,&dwFlags, sizeof (dwFlags) );
		return HttpSendRequest(hRequest,lpszHeaders,dwHeadersLength,lpOptional,dwOptionalLength);
	}

	return FALSE;
}