From: Dave Cheney <dave@cheney.net>
Date: Tue, 28 Aug 2012 23:05:30 +0000 (+1000)
Subject: net/http/httputil: fix race in DumpRequestOut
X-Git-Tag: go1.1rc2~2576
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=f8d4bb884fdb7dc98ee9fb12a9847cb1f322ecbc;p=gostls13.git

net/http/httputil: fix race in DumpRequestOut

Fixes #3892.

Swapping the order of the writers inside the MultiWriter ensures
the request will be written to buf before http.ReadRequest completes.

The fencedBuffer is not required to make the test pass on
any machine that I have access too, but as the buf is shared
across goroutines, I think it is necessary for correctness.

R=bradfitz, fullung, franciscossouza
CC=golang-dev
https://golang.org/cl/6483061
---

diff --git a/src/pkg/net/http/httputil/dump.go b/src/pkg/net/http/httputil/dump.go
index 5a95eb8cc2..0b00356616 100644
--- a/src/pkg/net/http/httputil/dump.go
+++ b/src/pkg/net/http/httputil/dump.go
@@ -89,7 +89,7 @@ func DumpRequestOut(req *http.Request, body bool) ([]byte, error) {
 
 	t := &http.Transport{
 		Dial: func(net, addr string) (net.Conn, error) {
-			return &dumpConn{io.MultiWriter(pw, &buf), dr}, nil
+			return &dumpConn{io.MultiWriter(&buf, pw), dr}, nil
 		},
 	}