version: use crypt32 instead of go x509 for cn extraction for file size

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 24 insertions, 15 deletions

diff --git a/version/wintrust/certificate_windows.go b/version/wintrust/certificate_windows.go
index cf254e4f..8c933f11 100644
--- a/version/wintrust/certificate_windows.go
+++ b/version/wintrust/certificate_windows.go
@@ -6,7 +6,6 @@
 package wintrust
 
 import (
-	"crypto/x509"
 	"syscall"
 	"unsafe"
 
@@ -14,26 +13,28 @@ import (
 )
 
 const (
-	CERT_QUERY_OBJECT_FILE                     = 1
-	CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED_EMBED = 1024
-	CERT_QUERY_FORMAT_FLAG_ALL                 = 14
+	_CERT_QUERY_OBJECT_FILE                     = 1
+	_CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED_EMBED = 1024
+	_CERT_QUERY_FORMAT_FLAG_ALL                 = 14
+	_CERT_NAME_SIMPLE_DISPLAY_TYPE              = 4
 )
 
-//sys	CryptQueryObject(objectType uint32, object uintptr, expectedContentTypeFlags uint32, expectedFormatTypeFlags uint32, flags uint32, msgAndCertEncodingType *uint32, contentType *uint32, formatType *uint32, certStore *windows.Handle, msg *windows.Handle, context *uintptr) (err error) = crypt32.CryptQueryObject
+//sys	cryptQueryObject(objectType uint32, object uintptr, expectedContentTypeFlags uint32, expectedFormatTypeFlags uint32, flags uint32, msgAndCertEncodingType *uint32, contentType *uint32, formatType *uint32, certStore *windows.Handle, msg *windows.Handle, context *uintptr) (err error) = crypt32.CryptQueryObject
+//sys	certGetNameString(certContext *windows.CertContext, nameType uint32, flags uint32, typePara uintptr, name *uint16, size uint32) (chars uint32) = crypt32.CertGetNameStringW
 
-func ExtractCertificates(path string) ([]x509.Certificate, error) {
+func ExtractCertificateNames(path string) ([]string, error) {
 	path16, err := windows.UTF16PtrFromString(path)
 	if err != nil {
 		return nil, err
 	}
 	var certStore windows.Handle
-	err = CryptQueryObject(CERT_QUERY_OBJECT_FILE, uintptr(unsafe.Pointer(path16)), CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED_EMBED, CERT_QUERY_FORMAT_FLAG_ALL, 0, nil, nil, nil, &certStore, nil, nil)
+	err = cryptQueryObject(_CERT_QUERY_OBJECT_FILE, uintptr(unsafe.Pointer(path16)), _CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED_EMBED, _CERT_QUERY_FORMAT_FLAG_ALL, 0, nil, nil, nil, &certStore, nil, nil)
 	if err != nil {
 		return nil, err
 	}
 	defer windows.CertCloseStore(certStore, 0)
-	var certs []x509.Certificate
 	var cert *windows.CertContext
+	var names []string
 	for {
 		cert, err = windows.CertEnumCertificatesInStore(certStore, cert)
 		if err != nil {
@@ -47,13 +48,21 @@ func ExtractCertificates(path string) ([]x509.Certificate, error) {
 		if cert == nil {
 			break
 		}
-		buf := make([]byte, cert.Length)
-		copy(buf, (*[1 << 20]byte)(unsafe.Pointer(cert.EncodedCert))[:])
-		if c, err := x509.ParseCertificate(buf); err == nil {
-			certs = append(certs, *c)
-		} else {
-			return nil, err
+		nameLen := certGetNameString(cert, _CERT_NAME_SIMPLE_DISPLAY_TYPE, 0, 0, nil, 0)
+		if nameLen == 0 {
+			continue
+		}
+		name16 := make([]uint16, nameLen)
+		if certGetNameString(cert, _CERT_NAME_SIMPLE_DISPLAY_TYPE, 0, 0, &name16[0], nameLen) != nameLen {
+			continue
 		}
+		if name16[0] == 0 {
+			continue
+		}
+		names = append(names, windows.UTF16ToString(name16))
+	}
+	if names == nil {
+		return nil, syscall.Errno(windows.CRYPT_E_NOT_FOUND)
 	}
-	return certs, nil
+	return names, nil
 }