[19.03] ssh: avoid setting flags through hostname

cli/connhelper/connhelper.go

@@ -34,7 +34,7 @@ func GetConnectionHelper(daemonURL string) (*ConnectionHelper, error) {
 		}
 		return &ConnectionHelper{
 			Dialer: func(ctx context.Context, network, addr string) (net.Conn, error) {
-				return commandconn.New(ctx, "ssh", append(sp.Args(), []string{"--", "docker", "system", "dial-stdio"}...)...)
+				return commandconn.New(ctx, "ssh", sp.Args("docker", "system", "dial-stdio")...)
 			},
 			Host: "http://docker",
 		}, nil

cli/connhelper/ssh/ssh.go

@@ -49,15 +49,16 @@ type Spec struct {
 	Port string
 }
 
-// Args returns args except "ssh" itself and "-- ..."
-func (sp *Spec) Args() []string {
+// Args returns args except "ssh" itself combined with optional additional command args
+func (sp *Spec) Args(add ...string) []string {
 	var args []string
 	if sp.User != "" {
 		args = append(args, "-l", sp.User)
 	}
 	if sp.Port != "" {
 		args = append(args, "-p", sp.Port)
 	}
-	args = append(args, sp.Host)
+	args = append(args, "--", sp.Host)
+	args = append(args, add...)
 	return args
 }

cli/connhelper/ssh/ssh_test.go

@@ -16,15 +16,15 @@ func TestParseURL(t *testing.T) {
 		{
 			url: "ssh://foo",
 			expectedArgs: []string{
-				"foo",
+				"--", "foo",
 			},
 		},
 		{
 			url: "ssh://me@foo:10022",
 			expectedArgs: []string{
 				"-l", "me",
 				"-p", "10022",
-				"foo",
+				"--", "foo",
 			},
 		},
 		{
@@ -53,12 +53,14 @@ func TestParseURL(t *testing.T) {
 		},
 	}
 	for _, tc := range testCases {
-		sp, err := ParseURL(tc.url)
-		if tc.expectedError == "" {
-			assert.NilError(t, err)
-			assert.Check(t, is.DeepEqual(tc.expectedArgs, sp.Args()))
-		} else {
-			assert.ErrorContains(t, err, tc.expectedError)
-		}
+		t.Run(tc.url, func(t *testing.T) {
+			sp, err := ParseURL(tc.url)
+			if tc.expectedError == "" {
+				assert.NilError(t, err)
+				assert.Check(t, is.DeepEqual(tc.expectedArgs, sp.Args()))
+			} else {
+				assert.ErrorContains(t, err, tc.expectedError)
+			}
+		})
 	}
 }