diff options
| -rw-r--r-- | src/net/http/request.go | 23 | ||||
| -rw-r--r-- | src/net/http/request_test.go | 17 |
2 files changed, 34 insertions, 6 deletions
diff --git a/src/net/http/request.go b/src/net/http/request.go index 3100037386..91cb8a66b9 100644 --- a/src/net/http/request.go +++ b/src/net/http/request.go @@ -582,8 +582,29 @@ func (r *Request) write(w io.Writer, usingProxy bool, extraHeaders Header, waitF if err != nil { return err } + // Validate that the Host header is a valid header in general, + // but don't validate the host itself. This is sufficient to avoid + // header or request smuggling via the Host field. + // The server can (and will, if it's a net/http server) reject + // the request if it doesn't consider the host valid. if !httpguts.ValidHostHeader(host) { - return errors.New("http: invalid Host header") + // Historically, we would truncate the Host header after '/' or ' '. + // Some users have relied on this truncation to convert a network + // address such as Unix domain socket path into a valid, ignored + // Host header (see https://go.dev/issue/61431). + // + // We don't preserve the truncation, because sending an altered + // header field opens a smuggling vector. Instead, zero out the + // Host header entirely if it isn't valid. (An empty Host is valid; + // see RFC 9112 Section 3.2.) + // + // Return an error if we're sending to a proxy, since the proxy + // probably can't do anything useful with an empty Host header. + if !usingProxy { + host = "" + } else { + return errors.New("http: invalid Host header") + } } // According to RFC 6874, an HTTP client, proxy, or other diff --git a/src/net/http/request_test.go b/src/net/http/request_test.go index fddc85d6a9..dd1e2dc2a1 100644 --- a/src/net/http/request_test.go +++ b/src/net/http/request_test.go @@ -770,16 +770,23 @@ func TestRequestWriteBufferedWriter(t *testing.T) { } } -func TestRequestBadHost(t *testing.T) { +func TestRequestBadHostHeader(t *testing.T) { got := []string{} req, err := NewRequest("GET", "http://foo/after", nil) if err != nil { t.Fatal(err) } - req.Host = "foo.com with spaces" - req.URL.Host = "foo.com with spaces" - if err := req.Write(logWrites{t, &got}); err == nil { - t.Errorf("Writing request with invalid Host: succeded, want error") + req.Host = "foo.com\nnewline" + req.URL.Host = "foo.com\nnewline" + req.Write(logWrites{t, &got}) + want := []string{ + "GET /after HTTP/1.1\r\n", + "Host: \r\n", + "User-Agent: " + DefaultUserAgent + "\r\n", + "\r\n", + } + if !reflect.DeepEqual(got, want) { + t.Errorf("Writes = %q\n Want = %q", got, want) } } |