Merge pull request #20924 from nextcloud/backport/20915/stable18

[stable18] Use random_bytes

1 files changed, 13 insertions, 7 deletions

diff --git a/lib/private/Security/Crypto.php b/lib/private/Security/Crypto.php
index ca17b6e2b8a..664e652bfc0 100644
--- a/lib/private/Security/Crypto.php
+++ b/lib/private/Security/Crypto.php
@@ -51,17 +51,14 @@ class Crypto implements ICrypto {
 	private $ivLength = 16;
 	/** @var IConfig */
 	private $config;
-	/** @var ISecureRandom */
-	private $random;
 
 	/**
 	 * @param IConfig $config
 	 * @param ISecureRandom $random
 	 */
-	public function __construct(IConfig $config, ISecureRandom $random) {
+	public function __construct(IConfig $config) {
 		$this->cipher = new AES();
 		$this->config = $config;
-		$this->random = $random;
 	}
 
 	/**
@@ -94,13 +91,14 @@ class Crypto implements ICrypto {
 		}
 		$this->cipher->setPassword($password);
 
-		$iv = $this->random->generate($this->ivLength);
+		$iv = \random_bytes($this->ivLength);
 		$this->cipher->setIV($iv);
 
 		$ciphertext = bin2hex($this->cipher->encrypt($plaintext));
+		$iv = bin2hex($iv);
 		$hmac = bin2hex($this->calculateHMAC($ciphertext.$iv, $password));
 
-		return $ciphertext.'|'.$iv.'|'.$hmac;
+		return $ciphertext.'|'.$iv.'|'.$hmac.'|2';
 	}
 
 	/**
@@ -118,7 +116,8 @@ class Crypto implements ICrypto {
 		$this->cipher->setPassword($password);
 
 		$parts = explode('|', $authenticatedCiphertext);
-		if (\count($parts) !== 3) {
+		$partCount = \count($parts);
+		if ($partCount < 3 || $partCount > 4) {
 			throw new \Exception('Authenticated ciphertext could not be decoded.');
 		}
 
@@ -126,6 +125,13 @@ class Crypto implements ICrypto {
 		$iv = $parts[1];
 		$hmac = hex2bin($parts[2]);
 
+		if ($partCount === 4) {
+			$version = $parts[3];
+			if ($version === '2') {
+				$iv = hex2bin($iv);
+			}
+		}
+
 		$this->cipher->setIV($iv);
 
 		if (!hash_equals($this->calculateHMAC($parts[0] . $parts[1], $password), $hmac)) {