Вот пример того, как декодировать данные исполняемого файла PKCS7 (CMS).
DWORD dwEncoding, dwContentType, dwFormatType;
HCERTSTORE hStore = NULL;
HCRYPTMSG hMsg = NULL;
// Get PKCS7 data
if(1)
{
// Must be an absolute path.
const wchar_t *filePath = L"C:\\Windows\\System32\\ntdll.dll";
if(!CryptQueryObject(CERT_QUERY_OBJECT_FILE, filePath,
CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED_EMBED,
CERT_QUERY_FORMAT_FLAG_BINARY, 0, &dwEncoding,
&dwContentType, &dwFormatType, &hStore,
&hMsg, NULL))
return 1;
}
else
{
/* Or do this if you want more control:
- load exe into memory
- find the certificate directory (WIN_CERTIFICATE)
WIN_CERTIFICATE &winCert = ...
CERT_BLOB certBlob = { winCert.dwLength, winCert.bCertificate };
if(!CryptQueryObject(CERT_QUERY_OBJECT_BLOB, &certBlob,
CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED,
CERT_QUERY_FORMAT_FLAG_BINARY, 0, &dwEncoding,
&dwContentType, &dwFormatType, &hStore,
&hMsg, NULL))
return 1;
*/
}
// Get signers information
DWORD dwSignerCount = 0;
DWORD dwSignerCountSize = sizeof(dwSignerCount);
if(!CryptMsgGetParam(hMsg, CMSG_SIGNER_COUNT_PARAM, 0, &dwSignerCount, &dwSignerCountSize))
return 1;
// The signer count seems to always be 1.
// Subsequent certificates can be retrieved like this:
// https://stackoverflow.com/q/36931928/2682312
for(DWORD i = 0; i < dwSignerCount; ++i)
{
DWORD cbSignerInfo;
if(!CryptMsgGetParam(hMsg, CMSG_SIGNER_INFO_PARAM, i, NULL, &cbSignerInfo))
return 1;
PCMSG_SIGNER_INFO pSignerInfo = (PCMSG_SIGNER_INFO)malloc(cbSignerInfo);
if(!CryptMsgGetParam(hMsg, CMSG_SIGNER_INFO_PARAM, i, pSignerInfo, &cbSignerInfo))
return 1;
// Do something with pSignerInfo->SerialNumber
// Enumerate nested certificates...
free(pSignerInfo);
}
return 0;