Skip to content

refactor(push): make encryption/signing more robust #2619

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
wants to merge 7 commits into
base: master
Choose a base branch
from
Draft

refactor(push): make encryption/signing more robust #2619

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
ecc7ed6
refactor(push): make encryption/signing more robust
joshtrichards Nov 1, 2025
a173f17
Add PushSigningException class for notifications
joshtrichards Nov 1, 2025
6323254
chore: fix namespace for PushSigningException
joshtrichards Nov 1, 2025
db30703
fix: catch sig exception and skip device
joshtrichards Nov 1, 2025
23d3a62
chore: make pushDeleteToDevice consistent with pushToDevice
joshtrichards Nov 1, 2025
2bc74ae
chore: tidy up
joshtrichards Nov 1, 2025
c6cf1a5
chore: Add tests for push to device signing errors
joshtrichards Nov 1, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions lib/Exceptions/PushSigningException.php
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,13 @@
<?php

declare(strict_types=1);

/**
* SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
* SPDX-License-Identifier: AGPL-3.0-or-later
*/

namespace OCA\Notifications\Exceptions;

class PushSigningException extends \RuntimeException {
}
196 changes: 145 additions & 51 deletions lib/Push.php
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
use OC\Security\IdentityProof\Key;
use OC\Security\IdentityProof\Manager;
use OCA\Notifications\AppInfo\Application;
use OCA\Notifications\Exceptions\PushSigningException;
use OCP\AppFramework\Http;
use OCP\AppFramework\Utility\ITimeFactory;
use OCP\Authentication\Exceptions\InvalidTokenException;
Expand Down Expand Up @@ -287,21 +288,29 @@
continue;
}

$proxyServer = rtrim($device['proxyserver'], '/');
if (!isset($this->payloadsToSend[$proxyServer])) {
$this->payloadsToSend[$proxyServer] = [];
}

// Encrypt and sign payload
try {
$payload = json_encode($this->encryptAndSign($userKey, $device, $id, $notification, $isTalkNotification), JSON_THROW_ON_ERROR);

$proxyServer = rtrim($device['proxyserver'], '/');
if (!isset($this->payloadsToSend[$proxyServer])) {
$this->payloadsToSend[$proxyServer] = [];
}
$this->payloadsToSend[$proxyServer][] = $payload;
} catch (\JsonException $e) {
$this->log->error('JSON error while encoding push notification: ' . $e->getMessage(), ['exception' => $e]);
// TODO: throw? continue?
} catch (\InvalidArgumentException) {
// Failed to encrypt message for device: public key is invalid
$this->deletePushToken($device['token']);
} catch (PushSigningException $e) {
// Server-side key problem: log already done; skip this device.
continue;
}

// All good!
$this->payloadsToSend[$proxyServer][] = $payload;

Check failure on line 311 in lib/Push.php

View workflow job for this annotation

GitHub Actions / static-psalm-analysis

PossiblyUndefinedVariable 

lib/Push.php:311:44: PossiblyUndefinedVariable: Possibly undefined variable $payload defined in try block (see https://psalm.dev/018)
}

$this->printInfo('');

if (!$this->deferPayloads) {
Expand All @@ -316,6 +325,7 @@
*/
public function pushDeleteToDevice(string $userId, ?array $notificationIds, string $app = ''): void {
if (!$this->config->getSystemValueBool('has_internet_connection', true)) {
$this->printInfo('<error>Internet connectivity is disabled in configuration file - no push delete notifications will be sent</error>');
return;
}

Expand Down Expand Up @@ -364,49 +374,62 @@
$devices = $this->filterDeviceList($devices, $app);
}
if (empty($devices)) {
$this->printInfo('<comment>No devices found / left for user</comment>');
return;
}

// We don't push to devices that are older than 60 days
$maxAge = time() - 60 * 24 * 60 * 60;

$userKey = $this->keyManager->getKey($user);

$this->printInfo('Private user key size: ' . strlen($userKey->getPrivate()));
$this->printInfo('Public user key size: ' . strlen($userKey->getPublic()));

$this->printInfo('');
$this->printInfo('Found ' . count($devices) . ' devices registered for push delete notifications');

foreach ($devices as $device) {
$device['token'] = (int)$device['token'];
$this->printInfo('');
$this->printInfo('Device token: ' . $device['token']);

if (!$this->validateToken($device['token'], $maxAge)) {
// Token does not exist anymore
continue;
}

$proxyServer = rtrim($device['proxyserver'], '/');
if (!isset($this->payloadsToSend[$proxyServer])) {
$this->payloadsToSend[$proxyServer] = [];
}

try {
$proxyServer = rtrim($device['proxyserver'], '/');
if (!isset($this->payloadsToSend[$proxyServer])) {
$this->payloadsToSend[$proxyServer] = [];
}

if ($deleteAll) {
$data = $this->encryptAndSignDelete($userKey, $device, null);
try {
$this->payloadsToSend[$proxyServer][] = json_encode($data['payload'], JSON_THROW_ON_ERROR);
} catch (\JsonException $e) {
$this->log->error('JSON error while encoding push notification: ' . $e->getMessage(), ['exception' => $e]);
}
$payload = json_encode($data['payload'], JSON_THROW_ON_ERROR);
// All good!
$this->payloadsToSend[$proxyServer][] = $payload;
} else {
$temp = $notificationIds;

while (!empty($temp)) {
$data = $this->encryptAndSignDelete($userKey, $device, $temp);
$temp = $data['remaining'];
try {
$this->payloadsToSend[$proxyServer][] = json_encode($data['payload'], JSON_THROW_ON_ERROR);
} catch (\JsonException $e) {
$this->log->error('JSON error while encoding push notification: ' . $e->getMessage(), ['exception' => $e]);
}
$queue = $notificationIds;
while (!empty($queue)) {
$data = $this->encryptAndSignDelete($userKey, $device, $queue);
$payload = json_encode($data['payload'], JSON_THROW_ON_ERROR);
// All good!
$this->payloadsToSend[$proxyServer][] = $payload;
$queue = $data['remaining'];
}
}
} catch (\JsonException $e) {
$this->log->error('JSON error while encoding push notification: ' . $e->getMessage(), ['exception' => $e]);
// TODO: throw? continue?
} catch (\InvalidArgumentException) {
// Failed to encrypt message for device: public key is invalid
$this->deletePushToken($device['token']);
} catch (PushSigningException $e) {
// Server-side key problem: log already done; skip this device.
// TODO: Confirm remaining/queue is handled properly here (not a factor in pushToDevice())
continue;
}
}

Expand Down Expand Up @@ -603,22 +626,47 @@
* @psalm-return array{deviceIdentifier: string, pushTokenHash: string, subject: string, signature: string, priority: string, type: string}
* @throws InvalidTokenException
* @throws \InvalidArgumentException
* @throws \JsonException
* @throws PushSigningException
*/
protected function encryptAndSign(Key $userKey, array $device, int $id, INotification $notification, bool $isTalkNotification): array {

if (empty($device['devicepublickey']) || empty($userKey->getPrivate())) {
throw new \InvalidArgumentException('Missing device public key or user private key');
}

$data = [
'nid' => $id,
'app' => $notification->getApp(),
'subject' => '',
'subject' => '', // will get populated
'type' => $notification->getObjectType(),
'id' => $notification->getObjectId(),
];

// Max length of encryption is ~240, so we need to make sure the subject is shorter.
// Also, subtract two for encapsulating quotes will be added.
$maxDataLength = 200 - strlen(json_encode($data)) - 2;
$data['subject'] = Util::shortenMultibyteString($notification->getParsedSubject(), $maxDataLength);
if ($notification->getParsedSubject() !== $data['subject']) {
$data['subject'] .= '…';
// Calculate maximum plaintext data length
// Assume a gross maximum data length of 245 - i.e. the minimum potential RSA public key modulus length of 256 bytes (2048 bits) minus 11 bytes for PKCS#1 v1.5 padding
$maxPlain = 256 - 11 - 2; // adjust if modulus length and/or padding changes

// Calculate encoded base data length and maximum subject length
$encodedBaseData = json_encode($data, JSON_THROW_ON_ERROR);
$encodedBaseDataBytes = strlen($encodedBaseData); // length of encoded data before populating subject
$maxSubjectBytes = max(0, $maxPlain - $encodedBaseDataBytes - 2); // subtract two for quotes

// Use proposed subject as-is if it's length is compliant otherwise truncate
$subject = $notification->getParsedSubject();
$originalBytes = strlen($subject);
if ($originalBytes <= $maxSubjectBytes) {
$data['subject'] = $subject;
} else {
$availableForText = max(0, $maxSubjectBytes - 3); // subtract three for ellipsis
$data['subject'] = Util::shortenMultibyteString($subject, $availableForText) . '…';
$this->log->debug('Truncated push notification subject to fit RSA size limit', [
'app' => 'notifications',
'user' => $notification->getUser(),
'deviceIdentifier' => $device['deviceidentifier'] ?? null,
'original_bytes' => $originalBytes,
'truncated_bytes' => strlen($data['subject']),
]);
}

if ($isTalkNotification) {
Expand All @@ -632,29 +680,44 @@
$type = 'alert';
}

$encodedData = json_encode($data, JSON_THROW_ON_ERROR);

$this->printInfo('Device public key size: ' . strlen($device['devicepublickey']));
$this->printInfo('Data to encrypt is: ' . json_encode($data));
$this->printInfo('Data to encrypt is: ' . $encodedData);

if (!openssl_public_encrypt(json_encode($data), $encryptedSubject, $device['devicepublickey'], OPENSSL_PKCS1_PADDING)) {
// Encrypt
if (openssl_public_encrypt($encodedData, $encryptedSubject, $device['devicepublickey'], OPENSSL_PKCS1_PADDING)) {
$this->printInfo('Encrypted push subject successfully');
} else {
$error = openssl_error_string();
$this->log->error($error, ['app' => 'notifications']);
$this->printInfo('<error>Error while encrypting data: "' . $error . '"</error>');
throw new \InvalidArgumentException('Failed to encrypt message for device');
$this->log->error('Error while encrypting push message: ' . $error, [
'app' => 'notifications',
'deviceIdentifier' => $device['deviceidentifier'] ?? null,
'uid' => $device['uid'] ?? null,
]);
$this->printInfo('<error>Error while encrypting push message: "' . $error . '"</error>');
throw new \InvalidArgumentException('Failed to encrypt push message for device');
}

// Sign
if (openssl_sign($encryptedSubject, $signature, $userKey->getPrivate(), OPENSSL_ALGO_SHA512)) {
$this->printInfo('Signed encrypted push subject');
} else {
$this->printInfo('<error>Failed to signed encrypted push subject</error>');
$error = openssl_error_string();
$this->log->error('Error while signing push message subject: ' . $error, [
'app' => 'notifications',
'deviceIdentifier' => $device['deviceidentifier'] ?? null,
'uid' => $device['uid'] ?? null,
]);
$this->printInfo('<error>Error while signing encrypted push subject</error>');
throw new PushSigningException('Failed to sign push message for device');
}
$base64EncryptedSubject = base64_encode($encryptedSubject);
$base64Signature = base64_encode($signature);

return [
'deviceIdentifier' => $device['deviceidentifier'],
'pushTokenHash' => $device['pushtokenhash'],
'subject' => $base64EncryptedSubject,
'signature' => $base64Signature,
'subject' => base64_encode($encryptedSubject),
'signature' => base64_encode($signature),
'priority' => $priority,
'type' => $type,
];
Expand All @@ -668,8 +731,15 @@
* @psalm-return array{remaining: list<int>, payload: array{deviceIdentifier: string, pushTokenHash: string, subject: string, signature: string, priority: string, type: string}}
* @throws InvalidTokenException
* @throws \InvalidArgumentException
* @throws \JsonException
* @throws PushSigningException
*/
protected function encryptAndSignDelete(Key $userKey, array $device, ?array $ids): array {

if (empty($device['devicepublickey']) || empty($userKey->getPrivate())) {
throw new \InvalidArgumentException('Missing device public key or user private key');
}

$remainingIds = [];
if ($ids === null) {
$data = [
Expand All @@ -688,22 +758,46 @@
];
}

if (!openssl_public_encrypt(json_encode($data), $encryptedSubject, $device['devicepublickey'], OPENSSL_PKCS1_PADDING)) {
$this->log->error(openssl_error_string(), ['app' => 'notifications']);
throw new \InvalidArgumentException('Failed to encrypt message for device');
$encodedData = json_encode($data, JSON_THROW_ON_ERROR);

$this->printInfo('Device public key size: ' . strlen($device['devicepublickey']));
$this->printInfo('Data to encrypt is: ' . $encodedData);

// Encrypt
if (openssl_public_encrypt($encodedData, $encryptedSubject, $device['devicepublickey'], OPENSSL_PKCS1_PADDING)) {
$this->printInfo('Encrypted push delete subject successfully');
} else {
$error = openssl_error_string();
$this->log->error('Error while encrypting push delete message: ' . $error, [
'app' => 'notifications',
'deviceIdentifier' => $device['deviceidentifier'] ?? null,
'uid' => $device['uid'] ?? null,
]);
$this->printInfo('<error>Error while encrypting push delete message: "' . $error . '"</error>');
throw new \InvalidArgumentException('Failed to encrypt push delete message for device');
}

openssl_sign($encryptedSubject, $signature, $userKey->getPrivate(), OPENSSL_ALGO_SHA512);
$base64EncryptedSubject = base64_encode($encryptedSubject);
$base64Signature = base64_encode($signature);
// Sign
if (openssl_sign($encryptedSubject, $signature, $userKey->getPrivate(), OPENSSL_ALGO_SHA512)) {
$this->printInfo('Signed encrypted push delete subject successfully');
} else {
$error = openssl_error_string();
$this->log->error('Error while signing encrypted push delete message subject: ' . $error, [
'app' => 'notifications',
'deviceIdentifier' => $device['deviceidentifier'] ?? null,
'uid' => $device['uid'] ?? null,
]);
$this->printInfo('<error>Error while signing encrypted push delete message</error>');
throw new PushSigningException('Failed to sign push delete message for device');
}

return [
'remaining' => $remainingIds,
'payload' => [
'deviceIdentifier' => $device['deviceidentifier'],
'pushTokenHash' => $device['pushtokenhash'],
'subject' => $base64EncryptedSubject,
'signature' => $base64Signature,
'subject' => base64_encode($encryptedSubject),
'signature' => base64_encode($signature),
'priority' => 'normal',
'type' => 'background',
]
Expand Down
Loading
Loading