181 lines
6.2 KiB
Diff
181 lines
6.2 KiB
Diff
From a357d15e9ee36a1232ae071d9968c4cf10a672b4 Mon Sep 17 00:00:00 2001
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From: Brad Fitzpatrick <bradfitz@golang.org>
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Date: Mon, 18 Jul 2016 06:05:24 +0000
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Subject: [PATCH] [release-branch.go1.6] net/http, net/http/cgi: fix for CGI +
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HTTP_PROXY security issue
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Because,
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* The CGI spec defines that incoming request header "Foo: Bar" maps to
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environment variable HTTP_FOO == "Bar". (see RFC 3875 4.1.18)
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* The HTTP_PROXY environment variable is conventionally used to configure
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the HTTP proxy for HTTP clients (and is respected by default for
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Go's net/http.Client and Transport)
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That means Go programs running in a CGI environment (as a child
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process under a CGI host) are vulnerable to an incoming request
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containing "Proxy: attacker.com:1234", setting HTTP_PROXY, and
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changing where Go by default proxies all outbound HTTP requests.
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This is CVE-2016-5386, aka https://httpoxy.org/
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Fixes #16405
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Change-Id: I6f68ade85421b4807785799f6d98a8b077e871f0
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Reviewed-on: https://go-review.googlesource.com/25010
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Run-TryBot: Chris Broadfoot <cbro@golang.org>
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TryBot-Result: Gobot Gobot <gobot@golang.org>
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Reviewed-by: Chris Broadfoot <cbro@golang.org>
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Reviewed-on: https://go-review.googlesource.com/25012
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---
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src/net/http/cgi/host.go | 4 ++++
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src/net/http/cgi/host_test.go | 37 ++++++++++++++++++++++++++++++++++---
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src/net/http/transport.go | 3 +++
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src/net/http/transport_test.go | 14 +++++++++++++-
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4 files changed, 54 insertions(+), 4 deletions(-)
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diff --git a/src/net/http/cgi/host.go b/src/net/http/cgi/host.go
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index 9b4d875..3f1600b 100644
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--- a/src/net/http/cgi/host.go
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+++ b/src/net/http/cgi/host.go
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@@ -145,6 +145,10 @@ func (h *Handler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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for k, v := range req.Header {
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k = strings.Map(upperCaseAndUnderscore, k)
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+ if k == "PROXY" {
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+ // See Issue 16405
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+ continue
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+ }
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joinStr := ", "
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if k == "COOKIE" {
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joinStr = "; "
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diff --git a/src/net/http/cgi/host_test.go b/src/net/http/cgi/host_test.go
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index 3327764..2783fe1 100644
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--- a/src/net/http/cgi/host_test.go
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+++ b/src/net/http/cgi/host_test.go
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@@ -34,15 +34,18 @@ func newRequest(httpreq string) *http.Request {
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return req
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}
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-func runCgiTest(t *testing.T, h *Handler, httpreq string, expectedMap map[string]string) *httptest.ResponseRecorder {
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+func runCgiTest(t *testing.T, h *Handler,
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+ httpreq string,
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+ expectedMap map[string]string, checks ...func(reqInfo map[string]string)) *httptest.ResponseRecorder {
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rw := httptest.NewRecorder()
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req := newRequest(httpreq)
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h.ServeHTTP(rw, req)
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- runResponseChecks(t, rw, expectedMap)
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+ runResponseChecks(t, rw, expectedMap, checks...)
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return rw
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}
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-func runResponseChecks(t *testing.T, rw *httptest.ResponseRecorder, expectedMap map[string]string) {
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+func runResponseChecks(t *testing.T, rw *httptest.ResponseRecorder,
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+ expectedMap map[string]string, checks ...func(reqInfo map[string]string)) {
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// Make a map to hold the test map that the CGI returns.
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m := make(map[string]string)
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m["_body"] = rw.Body.String()
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@@ -80,6 +83,9 @@ readlines:
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t.Errorf("for key %q got %q; expected %q", key, got, expected)
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}
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}
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+ for _, check := range checks {
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+ check(m)
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+ }
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}
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var cgiTested, cgiWorks bool
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@@ -235,6 +241,31 @@ func TestDupHeaders(t *testing.T) {
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expectedMap)
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}
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+// Issue 16405: CGI+http.Transport differing uses of HTTP_PROXY.
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+// Verify we don't set the HTTP_PROXY environment variable.
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+// Hope nobody was depending on it. It's not a known header, though.
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+func TestDropProxyHeader(t *testing.T) {
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+ check(t)
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+ h := &Handler{
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+ Path: "testdata/test.cgi",
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+ }
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+ expectedMap := map[string]string{
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+ "env-REQUEST_URI": "/myscript/bar?a=b",
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+ "env-SCRIPT_FILENAME": "testdata/test.cgi",
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+ "env-HTTP_X_FOO": "a",
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+ }
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+ runCgiTest(t, h, "GET /myscript/bar?a=b HTTP/1.0\n"+
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+ "X-Foo: a\n"+
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+ "Proxy: should_be_stripped\n"+
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+ "Host: example.com\n\n",
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+ expectedMap,
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+ func(reqInfo map[string]string) {
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+ if v, ok := reqInfo["env-HTTP_PROXY"]; ok {
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+ t.Errorf("HTTP_PROXY = %q; should be absent", v)
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+ }
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+ })
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+}
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+
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func TestPathInfoNoRoot(t *testing.T) {
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check(t)
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h := &Handler{
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diff --git a/src/net/http/transport.go b/src/net/http/transport.go
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index 1e3ea11..794b786 100644
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--- a/src/net/http/transport.go
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+++ b/src/net/http/transport.go
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@@ -216,6 +216,9 @@ func ProxyFromEnvironment(req *Request) (*url.URL, error) {
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}
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if proxy == "" {
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proxy = httpProxyEnv.Get()
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+ if proxy != "" && os.Getenv("REQUEST_METHOD") != "" {
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+ return nil, errors.New("net/http: refusing to use HTTP_PROXY value in CGI environment; see golang.org/s/cgihttpproxy")
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+ }
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}
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if proxy == "" {
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return nil, nil
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diff --git a/src/net/http/transport_test.go b/src/net/http/transport_test.go
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index d9da078..381432e 100644
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--- a/src/net/http/transport_test.go
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+++ b/src/net/http/transport_test.go
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@@ -1985,7 +1985,8 @@ type proxyFromEnvTest struct {
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env string // HTTP_PROXY
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httpsenv string // HTTPS_PROXY
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- noenv string // NO_RPXY
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+ noenv string // NO_PROXY
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+ reqmeth string // REQUEST_METHOD
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want string
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wanterr error
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@@ -2009,6 +2010,10 @@ func (t proxyFromEnvTest) String() string {
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space()
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fmt.Fprintf(&buf, "no_proxy=%q", t.noenv)
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}
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+ if t.reqmeth != "" {
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+ space()
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+ fmt.Fprintf(&buf, "request_method=%q", t.reqmeth)
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+ }
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req := "http://example.com"
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if t.req != "" {
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req = t.req
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@@ -2032,6 +2037,12 @@ var proxyFromEnvTests = []proxyFromEnvTest{
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{req: "https://secure.tld/", env: "http.proxy.tld", httpsenv: "secure.proxy.tld", want: "http://secure.proxy.tld"},
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{req: "https://secure.tld/", env: "http.proxy.tld", httpsenv: "https://secure.proxy.tld", want: "https://secure.proxy.tld"},
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+ // Issue 16405: don't use HTTP_PROXY in a CGI environment,
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+ // where HTTP_PROXY can be attacker-controlled.
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+ {env: "http://10.1.2.3:8080", reqmeth: "POST",
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+ want: "<nil>",
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+ wanterr: errors.New("net/http: refusing to use HTTP_PROXY value in CGI environment; see golang.org/s/cgihttpproxy")},
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+
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{want: "<nil>"},
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{noenv: "example.com", req: "http://example.com/", env: "proxy", want: "<nil>"},
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@@ -2047,6 +2058,7 @@ func TestProxyFromEnvironment(t *testing.T) {
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os.Setenv("HTTP_PROXY", tt.env)
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os.Setenv("HTTPS_PROXY", tt.httpsenv)
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os.Setenv("NO_PROXY", tt.noenv)
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+ os.Setenv("REQUEST_METHOD", tt.reqmeth)
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ResetCachedEnvironment()
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reqURL := tt.req
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if reqURL == "" {
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