From: cuiweixie <cuiweixie@gmail.com>
Date: Mon, 26 Sep 2022 14:49:08 +0000 (+0800)
Subject: syscall: check if to is nil to prevent panic from WSASendto
X-Git-Tag: go1.20rc1~934
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=52f9c6fdb0e5748406134e093e9fb791af14d300;p=gostls13.git

syscall: check if to is nil to prevent panic from WSASendto

to is an optional pointer to sockaddr, as written in the doc:
https://learn.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-wsasendto

For #55845

Change-Id: Ia685cec8d9bc9ff313f598db9d2213a1f409757a
Reviewed-on: https://go-review.googlesource.com/c/go/+/434535
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: xie cui <523516579@qq.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
---

diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index 420fd9e4bb..9547ae0720 100644
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -916,9 +916,13 @@ func Shutdown(fd Handle, how int) (err error) {
 }
 
 func WSASendto(s Handle, bufs *WSABuf, bufcnt uint32, sent *uint32, flags uint32, to Sockaddr, overlapped *Overlapped, croutine *byte) (err error) {
-	rsa, len, err := to.sockaddr()
-	if err != nil {
-		return err
+	var rsa unsafe.Pointer
+	var len int32
+	if to != nil {
+		rsa, len, err = to.sockaddr()
+		if err != nil {
+			return err
+		}
 	}
 	r1, _, e1 := Syscall9(procWSASendTo.Addr(), 9, uintptr(s), uintptr(unsafe.Pointer(bufs)), uintptr(bufcnt), uintptr(unsafe.Pointer(sent)), uintptr(flags), uintptr(unsafe.Pointer(rsa)), uintptr(len), uintptr(unsafe.Pointer(overlapped)), uintptr(unsafe.Pointer(croutine)))
 	if r1 == socket_error {