Merge pull request #5564 from ipfs/fix/5369

don't use the domain name as a filename in /ipns/a.com

Author: Stebalien

core/corehttp/gateway_handler.go

@@ -268,7 +268,7 @@ func (i *gatewayHandler) getOrHeadHandler(ctx context.Context, w http.ResponseWr
 			w.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename*=UTF-8''%s", url.PathEscape(urlFilename)))
 			name = urlFilename
 		} else {
-			name = gopath.Base(urlPath)
+			name = getFilename(urlPath)
 		}
 		i.serveFile(w, r, name, modtime, dr)
 		return
@@ -626,3 +626,11 @@ func webErrorWithCode(w http.ResponseWriter, message string, err error, code int
 func internalWebError(w http.ResponseWriter, err error) {
 	webErrorWithCode(w, "internalWebError", err, http.StatusInternalServerError)
 }
+
+func getFilename(s string) string {
+	if (strings.HasPrefix(s, ipfsPathPrefix) || strings.HasPrefix(s, ipnsPathPrefix)) && strings.Count(gopath.Clean(s), "/") <= 2 {
+		// Don't want to treat ipfs.io in /ipns/ipfs.io as a filename.
+		return ""
+	}
+	return gopath.Base(s)
+}

core/corehttp/gateway_test.go

@@ -153,6 +153,14 @@ func TestGatewayGet(t *testing.T) {
 	ns["/ipns/double.example.com"] = path.FromString("/ipns/working.example.com")
 	ns["/ipns/triple.example.com"] = path.FromString("/ipns/double.example.com")
 	ns["/ipns/broken.example.com"] = path.FromString("/ipns/" + k)
+	// We picked .man because:
+	// 1. It's a valid TLD.
+	// 2. Go treats it as the file extension for "man" files (even though
+	//    nobody actually *uses* this extension, AFAIK).
+	//
+	// Unfortunately, this may not work on all platforms as file type
+	// detection is platform dependent.
+	ns["/ipns/example.man"] = path.FromString("/ipfs/" + k)
 
 	t.Log(ts.URL)
 	for _, test := range []struct {
@@ -175,6 +183,8 @@ func TestGatewayGet(t *testing.T) {
 		{"working.example.com", "/ipfs/" + k, http.StatusNotFound, "ipfs resolve -r /ipns/working.example.com/ipfs/" + k + ": no link by that name\n"},
 		{"broken.example.com", "/", http.StatusNotFound, "ipfs resolve -r /ipns/broken.example.com/: " + namesys.ErrResolveFailed.Error() + "\n"},
 		{"broken.example.com", "/ipfs/" + k, http.StatusNotFound, "ipfs resolve -r /ipns/broken.example.com/ipfs/" + k + ": " + namesys.ErrResolveFailed.Error() + "\n"},
+		// This test case ensures we don't treat the TLD as a file extension.
+		{"example.man", "/", http.StatusOK, "fnord"},
 	} {
 		var c http.Client
 		r, err := http.NewRequest("GET", ts.URL+test.path, nil)
@@ -190,6 +200,10 @@ func TestGatewayGet(t *testing.T) {
 			continue
 		}
 		defer resp.Body.Close()
+		contentType := resp.Header.Get("Content-Type")
+		if contentType != "text/plain; charset=utf-8" {
+			t.Errorf("expected content type to be text/plain, got %s", contentType)
+		}
 		if resp.StatusCode != test.status {
 			t.Errorf("got %d, expected %d from %s", resp.StatusCode, test.status, urlstr)
 			continue