Fix ssh config must specify HostKeyCallback

Fixes: #5001

builder/alicloud/ecs/ssh_helper.go

@@ -49,6 +49,7 @@ func SSHConfig(useAgent bool, username, password string) func(multistep.StateBag
 				Auth: []ssh.AuthMethod{
 					ssh.PublicKeysCallback(agent.NewClient(sshAgent).Signers),
 				},
+				HostKeyCallback: ssh.InsecureIgnoreHostKey(),
 			}, nil
 		}
 
@@ -64,6 +65,7 @@ func SSHConfig(useAgent bool, username, password string) func(multistep.StateBag
 				Auth: []ssh.AuthMethod{
 					ssh.PublicKeys(signer),
 				},
+				HostKeyCallback: ssh.InsecureIgnoreHostKey(),
 			}, nil
 
 		} else {
@@ -73,7 +75,9 @@ func SSHConfig(useAgent bool, username, password string) func(multistep.StateBag
 					ssh.Password(password),
 					ssh.KeyboardInteractive(
 						packerssh.PasswordKeyboardInteractive(password)),
-				}}, nil
+				},
+				HostKeyCallback: ssh.InsecureIgnoreHostKey(),
+			}, nil
 		}
 	}
 }