3 files changed, 31 insertions, 4 deletions
diff --git a/lib/private/Security/Crypto.php b/lib/private/Security/Crypto.php
index e9ef4417925..aeeafcc271c 100644
--- a/lib/private/Security/Crypto.php
+++ b/lib/private/Security/Crypto.php
@@ -122,9 +122,22 @@ class Crypto implements ICrypto {
 	 * @throws Exception If the decryption failed
 	 */
 	public function decrypt(string $authenticatedCiphertext, string $password = ''): string {
-		if ($password === '') {
-			$password = $this->config->getSystemValue('secret');
+		$secret = $this->config->getSystemValue('secret');
+		try {
+			if ($password === '') {
+				return $this->decryptWithoutSecret($authenticatedCiphertext, $secret);
+			}
+			return $this->decryptWithoutSecret($authenticatedCiphertext, $password);
+		} catch (Exception $e) {
+			if ($password === '') {
+				// Retry with empty secret as a fallback for instances where the secret might not have been set by accident
+				return $this->decryptWithoutSecret($authenticatedCiphertext, '');
+			}
+			throw $e;
 		}
+	}
+
+	private function decryptWithoutSecret(string $authenticatedCiphertext, string $password = ''): string {
 		$hmacKey = $encryptionKey = $password;
 
 		$parts = explode('|', $authenticatedCiphertext);
diff --git a/lib/private/Security/Hasher.php b/lib/private/Security/Hasher.php
index 5b3fc2b47a9..4731ba96bd3 100644
--- a/lib/private/Security/Hasher.php
+++ b/lib/private/Security/Hasher.php
@@ -137,6 +137,15 @@ class Hasher implements IHasher {
 			return true;
 		}
 
+		// Verify whether it matches a legacy PHPass or SHA1 string
+		// Retry with empty passwordsalt for cases where it was not set
+		$hashLength = \strlen($hash);
+		if (($hashLength === 60 && password_verify($message, $hash)) ||
+			($hashLength === 40 && hash_equals($hash, sha1($message)))) {
+			$newHash = $this->hash($message);
+			return true;
+		}
+
 		return false;
 	}
 
diff --git a/lib/private/Security/VerificationToken/VerificationToken.php b/lib/private/Security/VerificationToken/VerificationToken.php
index c85e0e7b5a1..2d3f902b622 100644
--- a/lib/private/Security/VerificationToken/VerificationToken.php
+++ b/lib/private/Security/VerificationToken/VerificationToken.php
@@ -84,10 +84,15 @@ class VerificationToken implements IVerificationToken {
 		try {
 			$decryptedToken = $this->crypto->decrypt($encryptedToken, $passwordPrefix.$this->config->getSystemValue('secret'));
 		} catch (\Exception $e) {
-			$this->throwInvalidTokenException(InvalidTokenException::TOKEN_DECRYPTION_ERROR);
+			// Retry with empty secret as a fallback for instances where the secret might not have been set by accident
+			try {
+				$decryptedToken = $this->crypto->decrypt($encryptedToken, $passwordPrefix);
+			} catch (\Exception $e2) {
+				$this->throwInvalidTokenException(InvalidTokenException::TOKEN_DECRYPTION_ERROR);
+			}
 		}
 
-		$splitToken = explode(':', $decryptedToken ?? '');
+		$splitToken = explode(':', $decryptedToken);
 		if (count($splitToken) !== 2) {
 			$this->throwInvalidTokenException(InvalidTokenException::TOKEN_INVALID_FORMAT);
 		}