net/http: close resp.Body when error occurred during redirection

Fixes #19976

Change-Id: I48486467066784a9dcc24357ec94a1be85265a6f
Reviewed-on: https://go-review.googlesource.com/40940
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/net/http/client.go

@@ -524,10 +524,12 @@ func (c *Client) Do(req *Request) (*Response, error) {
 		if len(reqs) > 0 {
 			loc := resp.Header.Get("Location")
 			if loc == "" {
+				resp.closeBody()
 				return nil, uerr(fmt.Errorf("%d response missing Location header", resp.StatusCode))
 			}
 			u, err := req.URL.Parse(loc)
 			if err != nil {
+				resp.closeBody()
 				return nil, uerr(fmt.Errorf("failed to parse Location header %q: %v", loc, err))
 			}
 			ireq := reqs[0]
@@ -542,6 +544,7 @@ func (c *Client) Do(req *Request) (*Response, error) {
 			if includeBody && ireq.GetBody != nil {
 				req.Body, err = ireq.GetBody()
 				if err != nil {
+					resp.closeBody()
 					return nil, uerr(err)
 				}
 				req.ContentLength = ireq.ContentLength

src/net/http/response.go

@@ -321,3 +321,9 @@ func (r *Response) Write(w io.Writer) error {
 	// Success
 	return nil
 }
+
+func (r *Response) closeBody() {
+	if r.Body != nil {
+		r.Body.Close()
+	}
+}