phacility/phabricator · error · PhabricatorAuthSSHPrivateKeyFormatException

This private key is not formatted correctly. Check that you

Error message

This private key is not formatted correctly. Check that you have provided the complete text of a valid private key.

What it means

After all conclusive tests fail, PhabricatorAuthSSHPrivateKey matches ssh-keygen's stderr against known patterns. If the diagnostics match the 'format' pattern (ssh-keygen saying the key material is invalid), PhabricatorAuthSSHPrivateKeyFormatException is thrown: the key text itself is malformed, not a passphrase problem.

Source

Thrown at src/applications/auth/sshkey/PhabricatorAuthSSHPrivateKey.php:163

    $reason = 'unknown';
    foreach ($patterns as $pattern => $pattern_reason) {
      $ok = preg_match($pattern, $stderr);

      if ($ok === false) {
        throw new Exception(
          pht(
            'Pattern "%s" is not valid.',
            $pattern));
      }

      if ($ok) {
        $reason = $pattern_reason;
        break;
      }
    }

    if ($reason === $reason_format) {
      throw new PhabricatorAuthSSHPrivateKeyFormatException(
        pht(
          'This private key is not formatted correctly. Check that you '.
          'have provided the complete text of a valid private key.'));
    }

    if ($reason === $reason_passphrase) {
      if ($passphrase) {
        throw new PhabricatorAuthSSHPrivateKeyIncorrectPassphraseException(
          pht(
            'This private key requires a passphrase, but the wrong '.
            'passphrase was provided. Check that you supplied the correct '.
            'key and passphrase.'));
      } else {
        throw new PhabricatorAuthSSHPrivateKeyIncorrectPassphraseException(
          pht(
            'This private key requires a passphrase, but no passphrase was '.
            'provided. Check that you supplied the correct key, or provide '.
            'the passphrase.'));

View on GitHub (pinned to 5720a38cfe)

Solutions

1. Re-copy the entire key file including the '-----BEGIN ... PRIVATE KEY-----' and '-----END ... PRIVATE KEY-----' lines
2. If the key is a PuTTY .ppk, convert it first: puttygen key.ppk -O private-openssh -o key
3. Test locally with 'ssh-keygen -y -f keyfile' - if that fails on your machine, the key text is the problem
4. Upgrade openssh-client if it is ancient and the key uses a newer format

// Quick local sanity check before handing the key to Phabricator:
$body = trim($raw_key_text);
if (!preg_match('/-----BEGIN [A-Z0-9 ]*PRIVATE KEY-----/', $body) ||
    !preg_match('/-----END [A-Z0-9 ]*PRIVATE KEY-----/', $body)) {
  // Reject before import: key text is incomplete.
  return pht('Key must include complete BEGIN/END lines.');
}

try {
  $bare = $private_key->newBarePrivateKey($passphrase);
} catch (PhabricatorAuthSSHPrivateKeyFormatException $ex) {
  // Re-prompt: the key text itself is malformed, passphrase is irrelevant.
  $needs_reupload = true;
} catch (PhabricatorAuthSSHPrivateKeyException $ex) {
  throw $ex;
}

When it happens

Trigger: newBarePrivateKey() on a truncated or corrupted private key: missing BEGIN/END lines, partial base64 body from a copy/paste, Windows mangling, a PuTTY .ppk file, or a key format the installed ssh-keygen is too old to parse.

Common situations: Terminal/editor copy that dropped lines of the key; PuTTY users pasting .ppk directly; clipboard tools truncating long keys; very old openssh-client builds facing newer key formats.

Related errors

• A passphrase was provided for this private key, but it does
• This private key requires a passphrase, but the wrong passph
• This private key requires a passphrase, but no passphrase wa
• This private key could not be opened with the provided passp
• This private key could not be opened. This might mean that t

AI-assisted analysis of phacility/phabricator@5720a38cfe (2026-08-21). Data as JSON: /api/errors/f2708858428ffcd1. Report an issue: GitHub.