net: make protocol-specific WriteTo, WriteMsg methods return error instead of crash
R=golang-dev, dave, rsc, adg, bradfitz
CC=golang-dev
https://golang.org/cl/11809043
diff --git a/src/pkg/net/udpsock_plan9.go b/src/pkg/net/udpsock_plan9.go
index 12a3483..7362170 100644
--- a/src/pkg/net/udpsock_plan9.go
+++ b/src/pkg/net/udpsock_plan9.go
@@ -73,6 +73,9 @@
if !c.ok() || c.fd.data == nil {
return 0, syscall.EINVAL
}
+ if addr == nil {
+ return 0, &OpError{Op: "write", Net: c.fd.dir, Addr: nil, Err: errMissingAddress}
+ }
h := new(udpHeader)
h.raddr = addr.IP.To16()
h.laddr = c.fd.laddr.(*UDPAddr).IP.To16()
