crypto/x509: skip SHA2 system verify test if not supported.

Windows XP SP2 and Windows 2003 do not support SHA2.

Change-Id: Ica5faed040e9ced8b79fe78d512586e0e8788b3f
Reviewed-on: https://go-review.googlesource.com/8167
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/crypto/x509/sha2_windows_test.go

@@ -0,0 +1,15 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package x509
+
+import "internal/syscall/windows"
+
+func init() {
+	if major, _ := windows.GetVersion(); major < 6 {
+		// Windows XP SP2 and Windows 2003 do not support SHA2.
+		// http://blogs.technet.com/b/pki/archive/2010/09/30/sha2-and-windows.aspx
+		supportSHA2 = false
+	}
+}

src/crypto/x509/verify_test.go

@@ -14,6 +14,8 @@ import (
 	"time"
 )
 
+var supportSHA2 = true
+
 type verifyTest struct {
 	leaf                 string
 	intermediates        []string
@@ -23,6 +25,7 @@ type verifyTest struct {
 	systemSkip           bool
 	keyUsages            []ExtKeyUsage
 	testSystemRootsError bool
+	sha2                 bool
 
 	errorCallback  func(*testing.T, int, error) bool
 	expectedChains [][]string
@@ -218,6 +221,7 @@ var verifyTests = []verifyTest{
 		currentTime:   1397502195,
 		dnsName:       "api.moip.com.br",
 
+		sha2: true,
 		expectedChains: [][]string{
 			{
 				"api.moip.com.br",
@@ -297,6 +301,9 @@ func testVerify(t *testing.T, useSystemRoots bool) {
 		if runtime.GOOS == "windows" && test.testSystemRootsError {
 			continue
 		}
+		if useSystemRoots && !supportSHA2 && test.sha2 {
+			continue
+		}
 
 		opts := VerifyOptions{
 			Intermediates: NewCertPool(),

src/internal/syscall/windows/syscall_windows.go

@@ -97,6 +97,7 @@ const (
 //sys GetAdaptersAddresses(family uint32, flags uint32, reserved uintptr, adapterAddresses *IpAdapterAddresses, sizeOfPointer *uint32) (errcode error) = iphlpapi.GetAdaptersAddresses
 
 //sys	GetComputerNameEx(nameformat uint32, buf *uint16, n *uint32) (err error) = GetComputerNameExW
+//sys	getVersion() (v uint32) = GetVersion
 
 const (
 	ComputerNameNetBIOS                   = 0
@@ -109,3 +110,8 @@ const (
 	ComputerNamePhysicalDnsFullyQualified = 7
 	ComputerNameMax                       = 8
 )
+
+func GetVersion() (major, minor byte) {
+	low := uint16(getVersion())
+	return byte(low), byte(low >> 8)
+}

src/internal/syscall/windows/zsyscall_windows.go

@@ -13,6 +13,7 @@ var (
 
 	procGetAdaptersAddresses = modiphlpapi.NewProc("GetAdaptersAddresses")
 	procGetComputerNameExW   = modkernel32.NewProc("GetComputerNameExW")
+	procGetVersion           = modkernel32.NewProc("GetVersion")
 )
 
 func GetAdaptersAddresses(family uint32, flags uint32, reserved uintptr, adapterAddresses *IpAdapterAddresses, sizeOfPointer *uint32) (errcode error) {
@@ -34,3 +35,9 @@ func GetComputerNameEx(nameformat uint32, buf *uint16, n *uint32) (err error) {
 	}
 	return
 }
+
+func getVersion() (v uint32) {
+	r0, _, _ := syscall.Syscall(procGetVersion.Addr(), 0, 0, 0, 0)
+	v = uint32(r0)
+	return
+}