0001-SECURITY-Always-use-a-unique-nonce-IV-for-AES-CTR-en.patch
Bawolff (Brian Wolff)
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	Bawolff
	Sep 10 2022, 12:26 AM

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0001-SECURITY-Always-use-a-unique-nonce-IV-for-AES-CTR-en.patch
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	From 3fe0074c04755caedef4f04d4cf65b093d9a45ab Mon Sep 17 00:00:00 2001
	From: Brian Wolff <bawolff+wn@gmail.com>
	Date: Fri, 9 Sep 2022 17:22:11 -0700
	Subject: [PATCH] SECURITY: Always use a unique nonce/IV for AES-CTR
	encryption.

	AES-CTR encryption catastrophically fails if 2 different messages
	are encrypted under the same key with the same nonce.

	This patch generates a new random nonce everytime a new encrypted
	token is generated.

	Bug: T315123
	---
	src/TokenManager.php \| 15 ++++++++-------
	1 file changed, 8 insertions(+), 7 deletions(-)

	diff --git a/src/TokenManager.php b/src/TokenManager.php
	index 1aee2d59..ba7d93db 100644
	--- a/src/TokenManager.php
	+++ b/src/TokenManager.php
	@@ -38,13 +38,15 @@ class TokenManager {
	*/
	public function encode( Session $session, array $data ): string {
	$key = $this->getSessionKey( $session );
	+ $iv = $this->getInitializationVector();
	return JWT::encode(
	[
	// Expiration Time https://tools.ietf.org/html/rfc7519#section-4.1.4
	// 24 hours from now
	'exp' => \MWTimestamp::time() + 86400,
	+ 'iv' => base64_encode( $iv ),
	// Encrypt the form data to prevent it from being leaked.
	- 'data' => $this->encrypt( $data, $this->getInitializationVector( $key ) ),
	+ 'data' => $this->encrypt( $data, $iv ),
	],
	$this->getSigningKey( $key ),
	self::SIGNING_ALGO
	@@ -85,7 +87,7 @@ class TokenManager {

	return $this->decrypt(
	$payload->data,
	- $this->getInitializationVector( $key )
	+ base64_decode( $payload->iv )
	);
	}

	@@ -115,14 +117,13 @@ class TokenManager {
	/**
	* Get the initialization vector.
	*
	- * This must be consistent between encryption and decryption
	- * and must be no more than 16 bytes in length.
	+ * This must be consistent between encryption and decryption,
	+ * must be no more than 16 bytes in length and never repeat.
	*
	- * @param string $sessionKey
	* @return string
	*/
	- private function getInitializationVector( string $sessionKey ): string {
	- return hash_hmac( 'md5', $sessionKey, $this->secret, true );
	+ private function getInitializationVector(): string {
	+ return random_bytes( 16 );
	}

	/**
	--
	2.30.2

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0001-SECURITY-Always-use-a-unique-nonce-IV-for-AES-CTR-en.patch
Bawolff (Brian Wolff)
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0001-SECURITY-Always-use-a-unique-nonce-IV-for-AES-CTR-en.patch
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