Add some security utilities

This adds some security utilities to core including:
- A library for basic crypto operations (e.g. to encrypt passwords)
- A better library for cryptographic actions which allows you to specify the charset
- A library for secure string comparisions

Remove .htaccess

Remove .htaccess

Fix typo

Add public API

Use timing constant comparision

Remove CBC constant

Adjust code

Remove confusing $this

4 files changed, 125 insertions, 0 deletions

diff --git a/lib/public/security/icrypto.php b/lib/public/security/icrypto.php
new file mode 100644
index 00000000000..e55eea8dd66
--- /dev/null
+++ b/lib/public/security/icrypto.php
@@ -0,0 +1,46 @@
+<?php
+/**
+ * Copyright (c) 2014 Lukas Reschke <lukas@owncloud.com>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+
+namespace OCP\Security;
+
+/**
+ * Class Crypto provides a high-level encryption layer using AES-CBC. If no key has been provided
+ * it will use the secret defined in config.php as key. Additionally the message will be HMAC'd.
+ *
+ * Usage:
+ * $encryptWithDefaultPassword = \OC::$server->getCrypto()->encrypt('EncryptedText');
+ * $encryptWithCustomPassword = \OC::$server->getCrypto()->encrypt('EncryptedText', 'password');
+ *
+ * @package OCP\Security
+ */
+interface ICrypto {
+
+	/**
+	 * @param string $message The message to authenticate
+	 * @param string $password Password to use (defaults to `secret` in config.php)
+	 * @return string Calculated HMAC
+	 */
+	public function calculateHMAC($message, $password = '');
+
+	/**
+	 * Encrypts a value and adds an HMAC (Encrypt-Then-MAC)
+	 * @param string $plaintext
+	 * @param string $password Password to encrypt, if not specified the secret from config.php will be taken
+	 * @return string Authenticated ciphertext
+	 */
+	public function encrypt($plaintext, $password = '');
+
+	/**
+	 * Decrypts a value and verifies the HMAC (Encrypt-Then-Mac)
+	 * @param string $authenticatedCiphertext
+	 * @param string $password Password to encrypt, if not specified the secret from config.php will be taken
+	 * @return string plaintext
+	 * @throws \Exception If the HMAC does not match
+	 */
+	public function decrypt($authenticatedCiphertext, $password = '');
+}
diff --git a/lib/public/security/isecurerandom.php b/lib/public/security/isecurerandom.php
new file mode 100644
index 00000000000..ae6e1d58451
--- /dev/null
+++ b/lib/public/security/isecurerandom.php
@@ -0,0 +1,53 @@
+<?php
+/**
+ * Copyright (c) 2014 Lukas Reschke <lukas@owncloud.com>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+
+namespace OCP\Security;
+
+/**
+ * Class SecureRandom provides a layer around RandomLib to generate
+ * secure random numbers.
+ *
+ * Usage:
+ * $rng = new \OC\Security\SecureRandom();
+ * $randomString = $rng->getMediumStrengthGenerator()->generateString(30);
+ *
+ * @package OCP\Security
+ */
+interface ISecureRandom {
+
+	/**
+	 * Convenience method to get a low strength random number generator.
+	 *
+	 * Low Strength should be used anywhere that random strings are needed
+	 * in a non-cryptographical setting. They are not strong enough to be
+	 * used as keys or salts. They are however useful for one-time use tokens.
+	 *
+	 * @return $this
+	 */
+	public function getLowStrengthGenerator();
+
+	/**
+	 * Convenience method to get a medium strength random number generator.
+	 *
+	 * Medium Strength should be used for most needs of a cryptographic nature.
+	 * They are strong enough to be used as keys and salts. However, they do
+	 * take some time and resources to generate, so they should not be over-used
+	 *
+	 * @return $this
+	 */
+	public function getMediumStrengthGenerator();
+
+	/**
+	 * Generate a random string of specified length.
+	 * @param string $length The length of the generated string
+	 * @param string $characters An optional list of characters to use
+	 * @return string
+	 * @throws \Exception
+	 */
+	public function generate($length, $characters = '');
+}
diff --git a/lib/public/security/stringutils.php b/lib/public/security/stringutils.php
new file mode 100644
index 00000000000..8e7b132724e
--- /dev/null
+++ b/lib/public/security/stringutils.php
@@ -0,0 +1,25 @@
+<?php
+/**
+ * Copyright (c) 2014 Lukas Reschke <lukas@owncloud.com>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+
+
+namespace OCP\Security;
+
+class StringUtils {
+	/**
+	 * Compares whether two strings are equal. To prevent guessing of the string
+	 * length this is done by comparing two hashes against each other and afterwards
+	 * a comparison of the real string to prevent against the unlikely chance of
+	 * collisions.
+	 * @param string $expected The expected value
+	 * @param string $input The input to compare against
+	 * @return bool True if the two strings are equal, otherwise false.
+	 */
+	public static function equals($expected, $input) {
+		return \OC\Security\StringUtils::equals($expected, $input);
+	}
+}
diff --git a/lib/public/util.php b/lib/public/util.php
index 87b7a4f19db..83a6155685b 100644
--- a/lib/public/util.php
+++ b/lib/public/util.php
@@ -505,6 +505,7 @@ class Util {
 	 * Generates a cryptographic secure pseudo-random string
 	 * @param int $length of the random string
 	 * @return string
+	 * @deprecated Use \OC::$server->getSecureRandom()->getMediumStrengthGenerator()->generate($length); instead
 	 */
 	public static function generateRandomBytes($length = 30) {
 		return \OC_Util::generateRandomBytes($length);