From b7f285e4e24247fedb94f030356fa6f291f525cc Mon Sep 17 00:00:00 2001
From: Yassine Doghri <yassine@doghri.fr>
Date: Sun, 30 Jan 2022 16:32:11 +0000
Subject: [PATCH] fix(http-signature): update SIGNATURE_PATTERN allowing
signature keys to be sent in any order
set algorithm key as optional and set defaults for both algorithm (rsa-sha256) and headers (date)
keys
---
modules/Fediverse/HttpSignature.php | 59 +++++++++++++++++++----------
1 file changed, 38 insertions(+), 21 deletions(-)
diff --git a/modules/Fediverse/HttpSignature.php b/modules/Fediverse/HttpSignature.php
index 1bd6412517..b0f489182e 100644
--- a/modules/Fediverse/HttpSignature.php
+++ b/modules/Fediverse/HttpSignature.php
@@ -28,18 +28,14 @@ class HttpSignature
/**
* @var string
*/
- private const SIGNATURE_PATTERN = '/^
- keyId="(?P<keyId>
- (https?:\/\/[\w\-\.]+[\w]+)
- (:[\d]+)?
- ([\w\-\.#\/@]+)
- )",
- algorithm="(?P<algorithm>[\w\-]+)",
- (headers="\(request-target\) (?P<headers>[\w\\-\s]+)",)?
- signature="(?P<signature>[\w+\/]+={0,2})"
+ private const SIGNATURE_PATTERN = '/
+ (?=.*(keyId="(?P<keyId>https?:\/\/[\w\-\.]+[\w]+(:[\d]+)?[\w\-\.#\/@]+)"))
+ (?=.*(signature="(?P<signature>[\w+\/]+={0,2})"))
+ (?=.*(headers="\(request-target\)(?P<headers>[\w\\-\s]+)"))?
+ (?=.*(algorithm="(?P<algorithm>[\w\-]+)"))?
/x';
- protected ?IncomingRequest $request = null;
+ protected IncomingRequest $request;
public function __construct(IncomingRequest $request = null)
{
@@ -66,7 +62,8 @@ class HttpSignature
$requestTime = Time::createFromFormat('D, d M Y H:i:s T', $dateHeader->getValue());
$diff = $requestTime->difference($currentTime);
- if ($diff->getSeconds() > 3600) {
+ $diffSeconds = $diff->getSeconds();
+ if ($diffSeconds > 3600 || $diffSeconds < 0) {
throw new Exception('Request must be made within the last hour.');
}
@@ -74,6 +71,7 @@ class HttpSignature
if (! ($digestHeader = $this->request->header('digest'))) {
throw new Exception('Request must include a digest header');
}
+
// compute body digest and compare with header digest
$bodyDigest = hash('sha256', $this->request->getBody(), true);
$digest = 'SHA-256=' . base64_encode($bodyDigest);
@@ -94,7 +92,8 @@ class HttpSignature
// set $keyId, $headers and $signature variables
$keyId = $parts['keyId'];
- $headers = $parts['headers'];
+ $algorithm = $parts['algorithm'];
+ $headers = $parts['headers'] ?? 'date';
$signature = $parts['signature'];
// Fetch the public key linked from keyId
@@ -102,19 +101,14 @@ class HttpSignature
$actorResponse = $actorRequest->get();
$actor = json_decode($actorResponse->getBody(), false, 512, JSON_THROW_ON_ERROR);
- $publicKeyPem = $actor->publicKey->publicKeyPem;
+ $publicKeyPem = (string) $actor->publicKey->publicKeyPem;
// Create a comparison string from the plaintext headers we got
// in the same order as was given in the signature header,
$data = $this->getPlainText(explode(' ', trim($headers)));
- // Verify that string using the public key and the original signature.
- $rsa = new RSA();
- $rsa->setHash('sha256');
- $rsa->setSignatureMode(RSA::SIGNATURE_PKCS1);
- $rsa->loadKey($publicKeyPem);
-
- return $rsa->verify($data, base64_decode($signature, true));
+ // Verify the data string using the public key and the original signature.
+ return $this->verifySignature($publicKeyPem, $data, $signature, $algorithm);
}
/**
@@ -124,7 +118,7 @@ class HttpSignature
*/
private function splitSignature(string $signature): array | false
{
- if (! preg_match(self::SIGNATURE_PATTERN, $signature, $matches)) {
+ if (! preg_match(self::SIGNATURE_PATTERN, $signature, $matches, PREG_UNMATCHED_AS_NULL)) {
// Signature pattern failed
return false;
}
@@ -162,4 +156,27 @@ class HttpSignature
return implode("\n", $strings);
}
+
+ /**
+ * Verifies the signature depending on the algorithm sent
+ */
+ private function verifySignature(
+ string $publicKeyPem,
+ string $data,
+ string $signature,
+ string $algorithm = 'rsa-sha256'
+ ): bool {
+ if ($algorithm === 'rsa-sha512' || $algorithm === 'rsa-sha256') {
+ $hash = substr($algorithm, strpos($algorithm, '-') + 1);
+ $rsa = new RSA();
+ $rsa->setHash($hash);
+ $rsa->setSignatureMode(RSA::SIGNATURE_PKCS1);
+ $rsa->loadKey($publicKeyPem);
+
+ return $rsa->verify($data, (string) base64_decode($signature, true));
+ }
+
+ // not implemented
+ return false;
+ }
}
--
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