Review fixes: a malformed key reads as damaged, removing a location always reports it, a key from before 1.1.0 in the recovery guide

- Invalid base64 or a wrong salt/nonce length in a key gives the damaged-key error, so the recovery options are shown
- Tidying up after a removed location cannot fail the removal anymore, so the removal event is always sent
- Recovery guide: a key made before 1.1.0 counts as used and cannot make way

lib/Crypto/KeyRing.php

@@ -108,10 +108,15 @@ final class KeyRing {
 			|| $wrapped['mem'] < SODIUM_CRYPTO_PWHASH_MEMLIMIT_INTERACTIVE || $wrapped['mem'] > SODIUM_CRYPTO_PWHASH_MEMLIMIT_SENSITIVE) {
 			throw new CryptoException('Unsupported key derivation parameters (damaged or foreign key file)');
 		}
-		$kek = sodium_crypto_pwhash(SODIUM_CRYPTO_SECRETBOX_KEYBYTES, $passphrase, $b64($wrapped['salt']),
-			$wrapped['ops'], $wrapped['mem'], SODIUM_CRYPTO_PWHASH_ALG_ARGON2ID13);
-		$master = sodium_crypto_secretbox_open($b64($wrapped['key']), $b64($wrapped['nonce']), $kek);
-		sodium_memzero($kek);
+		try {
+			$kek = sodium_crypto_pwhash(SODIUM_CRYPTO_SECRETBOX_KEYBYTES, $passphrase, $b64($wrapped['salt']),
+				$wrapped['ops'], $wrapped['mem'], SODIUM_CRYPTO_PWHASH_ALG_ARGON2ID13);
+			$master = sodium_crypto_secretbox_open($b64($wrapped['key']), $b64($wrapped['nonce']), $kek);
+			sodium_memzero($kek);
+		} catch (\SodiumException|\ValueError $e) {
+			// invalid base64 or a salt/nonce of the wrong length: damaged, so the caller shows its recovery options
+			throw new CryptoException('Damaged key file: ' . $e->getMessage(), 0, $e);
+		}
 		if ($master === false) {
 			throw new CryptoException('Wrong passphrase or damaged key');
 		}