net/http: ignore extra space between response version and status code

Reading a response with a status line like "HTTP/1.0  401 Unauthorized"
(with two spaces after the version) has been returning an error. Now the
extra space will be ignored.

Fixes #19989

Change-Id: I0c88a6ef7562ba80e2e2635be2070dd1b5b671a7
Reviewed-on: https://go-review.googlesource.com/40933Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/net/http/response.go

@@ -153,23 +153,23 @@ func ReadResponse(r *bufio.Reader, req *Request) (*Response, error) {
 		}
 		return nil, err
 	}
-	f := strings.SplitN(line, " ", 3)
-	if len(f) < 2 {
+	if i := strings.IndexByte(line, ' '); i == -1 {
 		return nil, &badStringError{"malformed HTTP response", line}
+	} else {
+		resp.Proto = line[:i]
+		resp.Status = strings.TrimLeft(line[i+1:], " ")
 	}
-	reasonPhrase := ""
-	if len(f) > 2 {
-		reasonPhrase = f[2]
+	statusCode := resp.Status
+	if i := strings.IndexByte(resp.Status, ' '); i != -1 {
+		statusCode = resp.Status[:i]
 	}
-	if len(f[1]) != 3 {
-		return nil, &badStringError{"malformed HTTP status code", f[1]}
+	if len(statusCode) != 3 {
+		return nil, &badStringError{"malformed HTTP status code", statusCode}
 	}
-	resp.StatusCode, err = strconv.Atoi(f[1])
+	resp.StatusCode, err = strconv.Atoi(statusCode)
 	if err != nil || resp.StatusCode < 0 {
-		return nil, &badStringError{"malformed HTTP status code", f[1]}
+		return nil, &badStringError{"malformed HTTP status code", statusCode}
 	}
-	resp.Status = f[1] + " " + reasonPhrase
-	resp.Proto = f[0]
 	var ok bool
 	if resp.ProtoMajor, resp.ProtoMinor, ok = ParseHTTPVersion(resp.Proto); !ok {
 		return nil, &badStringError{"malformed HTTP version", resp.Proto}

src/net/http/response_test.go

@@ -318,7 +318,7 @@ var respTests = []respTest{
 	{
 		"HTTP/1.0 303\r\n\r\n",
 		Response{
-			Status:        "303 ",
+			Status:        "303",
 			StatusCode:    303,
 			Proto:         "HTTP/1.0",
 			ProtoMajor:    1,
@@ -532,6 +532,29 @@ some body`,
 		},
 		"\x1f\x8b\b\x00\x00\x00\x00\x00\x00\x00s\xf3\xf7\a\x00\xab'\xd4\x1a\x03\x00\x00\x00",
 	},
+
+	// Issue 19989: two spaces between HTTP version and status.
+	{
+		"HTTP/1.0  401 Unauthorized\r\n" +
+			"Content-type: text/html\r\n" +
+			"WWW-Authenticate: Basic realm=\"\"\r\n\r\n" +
+			"Your Authentication failed.\r\n",
+		Response{
+			Status:     "401 Unauthorized",
+			StatusCode: 401,
+			Proto:      "HTTP/1.0",
+			ProtoMajor: 1,
+			ProtoMinor: 0,
+			Request:    dummyReq("GET"),
+			Header: Header{
+				"Content-Type":     {"text/html"},
+				"Www-Authenticate": {`Basic realm=""`},
+			},
+			Close:         true,
+			ContentLength: -1,
+		},
+		"Your Authentication failed.\r\n",
+	},
 }
 
 // tests successful calls to ReadResponse, and inspects the returned Response.