doc: update the minimum support Windows version

Also, remove some test code that was trying to work on XP and fix up
some comments referencing XP.

Fixes #26191
Updates #23380

Change-Id: I0b7319fe1954afddb22d396e5ec91d8c960268d8
Reviewed-on: https://go-review.googlesource.com/123415
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

doc/install.html

@@ -50,7 +50,7 @@ If your OS or architecture is not on the list, you may be able to
 <tr><td>FreeBSD 10.3 or later</td> <td>amd64, 386</td> <td>Debian GNU/kFreeBSD not supported</td></tr>
 <tr valign='top'><td>Linux 2.6.23 or later with glibc</td> <td>amd64, 386, arm, arm64,<br>s390x, ppc64le</td> <td>CentOS/RHEL 5.x not supported.<br>Install from source for other libc.</td></tr>
 <tr><td>macOS 10.10 or later</td> <td>amd64</td> <td>use the clang or gcc<sup>&#8224;</sup> that comes with Xcode<sup>&#8225;</sup> for <code>cgo</code> support</td></tr>
-<tr><td>Windows XP SP2 or later</td> <td>amd64, 386</td> <td>use MinGW gcc<sup>&#8224;</sup>. No need for cygwin or msys.</td></tr>
+<tr><td>Windows 7, Server 2008R2 or later</td> <td>amd64, 386</td> <td>use MinGW gcc<sup>&#8224;</sup>. No need for cygwin or msys.</td></tr>
 </table>
 
 <p>

src/crypto/x509/sha2_windows_test.go

-// 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 "syscall"
-
-func init() {
-	v, err := syscall.GetVersion()
-	if err != nil {
-		return
-	}
-	if major := byte(v); major < 6 {
-		// Windows XP SP2 and Windows 2003 do not support SHA2.
-		// https://blogs.technet.com/b/pki/archive/2010/09/30/sha2-and-windows.aspx
-		supportSHA2 = false
-	}
-}

src/crypto/x509/verify_test.go

@@ -15,8 +15,6 @@ import (
 	"time"
 )
 
-var supportSHA2 = true
-
 type verifyTest struct {
 	leaf                 string
 	intermediates        []string
@@ -427,9 +425,6 @@ 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/poll/fd_windows.go

@@ -34,12 +34,11 @@ var (
 
 var canCancelIO bool // determines if CancelIoEx API is present
 
-// This package uses SetFileCompletionNotificationModes Windows API
-// to skip calling GetQueuedCompletionStatus if an IO operation completes
-// synchronously. Unfortuently SetFileCompletionNotificationModes is not
-// available on Windows XP. Also there is a known bug where
-// SetFileCompletionNotificationModes crashes on some systems
-// (see https://support.microsoft.com/kb/2568167 for details).
+// This package uses the SetFileCompletionNotificationModes Windows
+// API to skip calling GetQueuedCompletionStatus if an IO operation
+// completes synchronously. There is a known bug where
+// SetFileCompletionNotificationModes crashes on some systems (see
+// https://support.microsoft.com/kb/2568167 for details).
 
 var useSetFileCompletionNotificationModes bool // determines is SetFileCompletionNotificationModes is present and safe to use
 

src/net/interface_windows.go

@@ -65,9 +65,8 @@ func interfaceTable(ifindex int) ([]Interface, error) {
 			}
 			// For now we need to infer link-layer service
 			// capabilities from media types.
-			// We will be able to use
-			// MIB_IF_ROW2.AccessType once we drop support
-			// for Windows XP.
+			// TODO: use MIB_IF_ROW2.AccessType now that we no longer support
+			// Windows XP.
 			switch aa.IfType {
 			case windows.IF_TYPE_ETHERNET_CSMACD, windows.IF_TYPE_ISO88025_TOKENRING, windows.IF_TYPE_IEEE80211, windows.IF_TYPE_IEEE1394:
 				ifi.Flags |= FlagBroadcast | FlagMulticast

src/runtime/syscall_windows.go

@@ -107,11 +107,12 @@ func syscall_loadsystemlibrary(filename *uint16) (handle, err uintptr) {
 		}{filename, 0, _LOAD_LIBRARY_SEARCH_SYSTEM32}
 		c.args = uintptr(noescape(unsafe.Pointer(&args)))
 	} else {
-		// User is on Windows XP or something ancient.
-		// The caller wanted to only load the filename DLL
-		// from the System32 directory but that facility
-		// doesn't exist, so just load it the normal way. This
-		// is a potential security risk, but so is Windows XP.
+		// User doesn't have KB2533623 installed. The caller
+		// wanted to only load the filename DLL from the
+		// System32 directory but that facility doesn't exist,
+		// so just load it the normal way. This is a potential
+		// security risk, but so is not installing security
+		// updates.
 		c.fn = getLoadLibrary()
 		c.n = 1
 		c.args = uintptr(noescape(unsafe.Pointer(&filename)))