Commit 829c5df5 authored by Brad Fitzpatrick's avatar Brad Fitzpatrick

net/url, net/http: reject control characters in URLs

This is a more conservative version of the reverted CL 99135 (which
was reverted in CL 137716)

The net/url part rejects URLs with ASCII CTLs from being parsed and
the net/http part rejects writing them if a bogus url.URL is
constructed otherwise.

Updates #27302
Updates #22907

Change-Id: I09a2212eb74c63db575223277aec363c55421ed8
Reviewed-on: https://go-review.googlesource.com/c/159157
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarFilippo Valsorda <filippo@golang.org>
parent 4edea0f0
......@@ -583,16 +583,23 @@ func TestFileServerZeroByte(t *testing.T) {
ts := httptest.NewServer(FileServer(Dir(".")))
defer ts.Close()
res, err := Get(ts.URL + "/..\x00")
c, err := net.Dial("tcp", ts.Listener.Addr().String())
if err != nil {
t.Fatal(err)
}
b, err := ioutil.ReadAll(res.Body)
defer c.Close()
_, err = fmt.Fprintf(c, "GET /..\x00 HTTP/1.0\r\n\r\n")
if err != nil {
t.Fatal(err)
}
var got bytes.Buffer
bufr := bufio.NewReader(io.TeeReader(c, &got))
res, err := ReadResponse(bufr, nil)
if err != nil {
t.Fatal("reading Body:", err)
t.Fatal("ReadResponse: ", err)
}
if res.StatusCode == 200 {
t.Errorf("got status 200; want an error. Body is:\n%s", string(b))
t.Errorf("got status 200; want an error. Body is:\n%s", got.Bytes())
}
}
......
......@@ -59,6 +59,12 @@ func isASCII(s string) bool {
return true
}
// isCTL reports whether r is an ASCII control character, including
// the Extended ASCII control characters included in Unicode.
func isCTL(r rune) bool {
return r < ' ' || 0x7f <= r && r <= 0x9f
}
func hexEscapeNonASCII(s string) string {
newLen := 0
for i := 0; i < len(s); i++ {
......
......@@ -550,7 +550,12 @@ func (r *Request) write(w io.Writer, usingProxy bool, extraHeaders Header, waitF
ruri = r.URL.Opaque
}
}
// TODO(bradfitz): escape at least newlines in ruri?
if strings.IndexFunc(ruri, isCTL) != -1 {
return errors.New("net/http: can't write control character in Request.URL")
}
// TODO: validate r.Method too? At least it's less likely to
// come from an attacker (more likely to be a constant in
// code).
// Wrap the writer in a bufio Writer if it's not already buffered.
// Don't always call NewWriter, as that forces a bytes.Buffer
......
......@@ -576,6 +576,17 @@ var reqWriteTests = []reqWriteTest{
"User-Agent: Go-http-client/1.1\r\n" +
"X-Foo: X-Bar\r\n\r\n",
},
25: {
Req: Request{
Method: "GET",
URL: &url.URL{
Host: "www.example.com",
RawQuery: "new\nline", // or any CTL
},
},
WantError: errors.New("net/http: can't write control character in Request.URL"),
},
}
func TestRequestWrite(t *testing.T) {
......
......@@ -513,6 +513,10 @@ func parse(rawurl string, viaRequest bool) (*URL, error) {
var rest string
var err error
if strings.IndexFunc(rawurl, isCTL) != -1 {
return nil, errors.New("net/url: invalid control character in URL")
}
if rawurl == "" && viaRequest {
return nil, errors.New("empty url")
}
......@@ -1134,3 +1138,9 @@ func validUserinfo(s string) bool {
}
return true
}
// isCTL reports whether r is an ASCII control character, including
// the Extended ASCII control characters included in Unicode.
func isCTL(r rune) bool {
return r < ' ' || 0x7f <= r && r <= 0x9f
}
......@@ -1738,12 +1738,27 @@ func TestNilUser(t *testing.T) {
}
func TestInvalidUserPassword(t *testing.T) {
_, err := Parse("http://us\ner:pass\nword@foo.com/")
_, err := Parse("http://user^:passwo^rd@foo.com/")
if got, wantsub := fmt.Sprint(err), "net/url: invalid userinfo"; !strings.Contains(got, wantsub) {
t.Errorf("error = %q; want substring %q", got, wantsub)
}
}
func TestRejectControlCharacters(t *testing.T) {
tests := []string{
"http://foo.com/?foo\nbar",
"http\r://foo.com/",
"http://foo\x7f.com/",
}
for _, s := range tests {
_, err := Parse(s)
const wantSub = "net/url: invalid control character in URL"
if got := fmt.Sprint(err); !strings.Contains(got, wantSub) {
t.Errorf("Parse(%q) error = %q; want substring %q", s, got, wantSub)
}
}
}
var escapeBenchmarks = []struct {
unescaped string
query string
......
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