Validator import password flag (#2228)

## Issue Addressed

#2224

## Proposed Changes

Add a `--password-file` option to the `lighthouse account validator import` command. The flag requires `--reuse-password` and will copy the password over to the `validator_definitions.yml` file. I used #2070 as a guide for validating the password as UTF-8 and stripping newlines.

## Additional Info



Co-authored-by: realbigsean <seananderson33@gmail.com>

account_manager/src/validator/import.rs

@@ -1,4 +1,4 @@
-use crate::wallet::create::STDIN_INPUTS_FLAG;
+use crate::wallet::create::{PASSWORD_FLAG, STDIN_INPUTS_FLAG};
 use account_utils::{
     eth2_keystore::Keystore,
     read_password_from_user,
@@ -65,6 +65,19 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                 .long(REUSE_PASSWORD_FLAG)
                 .help("If present, the same password will be used for all imported keystores."),
         )
+        .arg(
+            Arg::with_name(PASSWORD_FLAG)
+                .long(PASSWORD_FLAG)
+                .value_name("KEYSTORE_PASSWORD_PATH")
+                .requires(REUSE_PASSWORD_FLAG)
+                .help(
+                    "The path to the file containing the password which will unlock all \
+                    keystores being imported. This flag must be used with `--reuse-password`. \
+                    The password will be copied to the `validator_definitions.yml` file, so after \
+                    import we strongly recommend you delete the file at KEYSTORE_PASSWORD_PATH.",
+                )
+                .takes_value(true),
+        )
 }
 
 pub fn cli_run(matches: &ArgMatches, validator_dir: PathBuf) -> Result<(), String> {
@@ -72,6 +85,8 @@ pub fn cli_run(matches: &ArgMatches, validator_dir: PathBuf) -> Result<(), Strin
     let keystores_dir: Option<PathBuf> = clap_utils::parse_optional(matches, DIR_FLAG)?;
     let stdin_inputs = matches.is_present(STDIN_INPUTS_FLAG);
     let reuse_password = matches.is_present(REUSE_PASSWORD_FLAG);
+    let keystore_password_path: Option<PathBuf> =
+        clap_utils::parse_optional(matches, PASSWORD_FLAG)?;
 
     let mut defs = ValidatorDefinitions::open_or_create(&validator_dir)
         .map_err(|e| format!("Unable to open {}: {:?}", CONFIG_FILENAME, e))?;
@@ -131,6 +146,7 @@ pub fn cli_run(matches: &ArgMatches, validator_dir: PathBuf) -> Result<(), Strin
     // Reuses the same password for all keystores if the `REUSE_PASSWORD_FLAG` flag is set.
     let mut num_imported_keystores = 0;
     let mut previous_password: Option<ZeroizeString> = None;
+
     for src_keystore in &keystore_paths {
         let keystore = Keystore::from_json_file(src_keystore)
             .map_err(|e| format!("Unable to read keystore JSON {:?}: {:?}", src_keystore, e))?;
@@ -155,13 +171,23 @@ pub fn cli_run(matches: &ArgMatches, validator_dir: PathBuf) -> Result<(), Strin
             eprintln!();
             eprintln!("{}", PASSWORD_PROMPT);
 
-            let password = read_password_from_user(stdin_inputs)?;
-
-            if password.as_ref().is_empty() {
-                eprintln!("Continuing without password.");
-                sleep(Duration::from_secs(1)); // Provides nicer UX.
-                break None;
-            }
+            let password = match keystore_password_path.as_ref() {
+                Some(path) => {
+                    let password_from_file: ZeroizeString = fs::read_to_string(&path)
+                        .map_err(|e| format!("Unable to read {:?}: {:?}", path, e))?
+                        .into();
+                    password_from_file.without_newlines()
+                }
+                None => {
+                    let password_from_user = read_password_from_user(stdin_inputs)?;
+                    if password_from_user.as_ref().is_empty() {
+                        eprintln!("Continuing without password.");
+                        sleep(Duration::from_secs(1)); // Provides nicer UX.
+                        break None;
+                    }
+                    password_from_user
+                }
+            };
 
             match keystore.decrypt_keypair(password.as_ref()) {
                 Ok(_) => {

common/account_utils/src/lib.rs

@@ -188,6 +188,12 @@ impl ZeroizeString {
     pub fn as_str(&self) -> &str {
         &self.0
     }
+
+    /// Remove any number of newline or carriage returns from the end of a vector of bytes.
+    pub fn without_newlines(&self) -> ZeroizeString {
+        let stripped_string = self.0.trim_end_matches(|c| c == '\r' || c == '\n').into();
+        Self(stripped_string)
+    }
 }
 
 impl AsRef<[u8]> for ZeroizeString {
@@ -200,6 +206,54 @@ impl AsRef<[u8]> for ZeroizeString {
 mod test {
     use super::*;
 
+    #[test]
+    fn test_zeroize_strip_off() {
+        let expected = "hello world";
+
+        assert_eq!(
+            ZeroizeString::from("hello world\n".to_string())
+                .without_newlines()
+                .as_str(),
+            expected
+        );
+        assert_eq!(
+            ZeroizeString::from("hello world\n\n\n\n".to_string())
+                .without_newlines()
+                .as_str(),
+            expected
+        );
+        assert_eq!(
+            ZeroizeString::from("hello world\r".to_string())
+                .without_newlines()
+                .as_str(),
+            expected
+        );
+        assert_eq!(
+            ZeroizeString::from("hello world\r\r\r\r\r".to_string())
+                .without_newlines()
+                .as_str(),
+            expected
+        );
+        assert_eq!(
+            ZeroizeString::from("hello world\r\n".to_string())
+                .without_newlines()
+                .as_str(),
+            expected
+        );
+        assert_eq!(
+            ZeroizeString::from("hello world\r\n\r\n".to_string())
+                .without_newlines()
+                .as_str(),
+            expected
+        );
+        assert_eq!(
+            ZeroizeString::from("hello world".to_string())
+                .without_newlines()
+                .as_str(),
+            expected
+        );
+    }
+
     #[test]
     fn test_strip_off() {
         let expected = b"hello world".to_vec();

lighthouse/tests/account_manager.rs

@@ -497,6 +497,103 @@ fn validator_import_launchpad() {
     );
 }
 
+#[test]
+fn validator_import_launchpad_password_file() {
+    const PASSWORD: &str = "cats";
+    const PASSWORD_FILE_NAME: &str = "pw_is_cats.txt";
+    const KEYSTORE_NAME: &str = "keystore-m_12381_3600_0_0_0-1595406747.json";
+    const NOT_KEYSTORE_NAME: &str = "keystore-m_12381_3600_0_0-1595406747.json";
+
+    let src_dir = tempdir().unwrap();
+    let dst_dir = tempdir().unwrap();
+
+    let keypair = Keypair::random();
+    let keystore = KeystoreBuilder::new(&keypair, PASSWORD.as_bytes(), "".into())
+        .unwrap()
+        .build()
+        .unwrap();
+
+    let dst_keystore_dir = dst_dir.path().join(format!("0x{}", keystore.pubkey()));
+
+    // Create a keystore in the src dir.
+    File::create(src_dir.path().join(KEYSTORE_NAME))
+        .map(|mut file| keystore.to_json_writer(&mut file).unwrap())
+        .unwrap();
+
+    // Create a not-keystore file in the src dir.
+    File::create(src_dir.path().join(NOT_KEYSTORE_NAME)).unwrap();
+
+    // Create a password file in the src dir.
+    File::create(src_dir.path().join(PASSWORD_FILE_NAME))
+        .map(|mut file| file.write(PASSWORD.as_ref()))
+        .unwrap()
+        .unwrap();
+
+    let mut child = validator_cmd()
+        .arg(format!("--{}", VALIDATOR_DIR_FLAG))
+        .arg(dst_dir.path().as_os_str())
+        .arg(IMPORT_CMD)
+        .arg(format!("--{}", import::DIR_FLAG))
+        .arg(src_dir.path().as_os_str())
+        .arg(format!("--{}", import::REUSE_PASSWORD_FLAG))
+        .arg(format!("--{}", PASSWORD_FLAG))
+        .arg(src_dir.path().join(PASSWORD_FILE_NAME).as_os_str())
+        .spawn()
+        .unwrap();
+
+    child.wait().unwrap();
+
+    assert!(
+        src_dir.path().join(KEYSTORE_NAME).exists(),
+        "keystore should not be removed from src dir"
+    );
+    assert!(
+        src_dir.path().join(NOT_KEYSTORE_NAME).exists(),
+        "not-keystore should not be removed from src dir."
+    );
+    assert!(
+        src_dir.path().join(PASSWORD_FILE_NAME).exists(),
+        "password file should not be removed from src dir."
+    );
+
+    let voting_keystore_path = dst_keystore_dir.join(KEYSTORE_NAME);
+
+    assert!(
+        voting_keystore_path.exists(),
+        "keystore should be present in dst dir"
+    );
+    assert!(
+        !dst_dir.path().join(NOT_KEYSTORE_NAME).exists(),
+        "not-keystore should not be present in dst dir"
+    );
+    assert!(
+        !dst_dir.path().join(PASSWORD_FILE_NAME).exists(),
+        "password file should not be present in dst dir"
+    );
+
+    // Validator should be registered with slashing protection.
+    check_slashing_protection(&dst_dir, std::iter::once(keystore.public_key().unwrap()));
+
+    let defs = ValidatorDefinitions::open(&dst_dir).unwrap();
+
+    let expected_def = ValidatorDefinition {
+        enabled: true,
+        description: "".into(),
+        voting_public_key: keystore.public_key().unwrap(),
+        graffiti: None,
+        signing_definition: SigningDefinition::LocalKeystore {
+            voting_keystore_path,
+            voting_keystore_password_path: None,
+            voting_keystore_password: Some(ZeroizeString::from(PASSWORD.to_string())),
+        },
+    };
+
+    assert!(
+        defs.as_slice() == &[expected_def],
+        "validator defs file should be accurate"
+    );
+}
+
 /// Check that all of the given pubkeys have been registered with slashing protection.
 fn check_slashing_protection(validator_dir: &TempDir, pubkeys: impl Iterator<Item = PublicKey>) {
     let slashing_db_path = validator_dir.path().join(SLASHING_PROTECTION_FILENAME);