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Create V2 signatures if the minimum target NC is 19 

The v2 signature is also reproducable in other languages. As the hashes
are just stored as a single string that is signed. This is then also
verified.

To be backwards compatible such v2 signatures should only be generated
for apps that have a minimum version of NC19

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>
This commit is contained in:
Roeland Jago Douma 2019-12-18 20:55:21 +01:00
parent 20ce9e89c1
commit ac27507f0f
No known key found for this signature in database
GPG Key ID: F941078878347C0C
2 changed files with 67 additions and 13 deletions
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74
lib/private/IntegrityCheck/Checker.php
View File

@ -215,19 +215,28 @@ class Checker {
*/
private function createSignatureData(array $hashes,
X509 $certificate,
RSA $privateKey): array {
RSA $privateKey,
int $version): array {
ksort($hashes);
$privateKey->setSignatureMode(RSA::SIGNATURE_PSS);
$privateKey->setMGFHash('sha512');
// See https://tools.ietf.org/html/rfc3447#page-38
$privateKey->setSaltLength(0);
$signature = $privateKey->sign(json_encode($hashes));
$encodedHashed = json_encode($hashes);
$signature = $privateKey->sign($encodedHashed);
$hashesOutput = $hashes;
if ($version === 2) {
$hashesOutput = $encodedHashed;
}
return [
'hashes' => $hashes,
'hashes' => $hashesOutput,
'signature' => base64_encode($signature),
'certificate' => $certificate->saveX509($certificate->currentCert),
'version' => 2,
];
}
@ -239,16 +248,18 @@ class Checker {
* @param RSA $privateKey
* @throws \Exception
*/
public function writeAppSignature($path,
public function writeAppSignature(string $path,
X509 $certificate,
RSA $privateKey) {
$appInfoDir = $path . '/appinfo';
try {
$this->fileAccessHelper->assertDirectoryExists($appInfoDir);
$version = $this->maxSignatureVersion($appInfoDir . '/info.xml');
$iterator = $this->getFolderIterator($path);
$hashes = $this->generateHashes($iterator, $path);
$signature = $this->createSignatureData($hashes, $certificate, $privateKey);
$signature = $this->createSignatureData($hashes, $certificate, $privateKey, $version);
$this->fileAccessHelper->file_put_contents(
$appInfoDir . '/signature.json',
json_encode($signature, JSON_PRETTY_PRINT)
@ -261,6 +272,34 @@ class Checker {
}
}
/**
* Checkl if we can sign the app with the v2 signature
*/
private function maxSignatureVersion(string $appInfoPath): int {
if (!file_exists($appInfoPath)) {
return 1;
}
$content = file_get_contents($appInfoPath);
try {
$xml = new \SimpleXMLElement($content);
$minNextcloudVersion = $xml->dependencies->nextcloud['min-version'];
if ($minNextcloudVersion === NULL) {
return 1;
}
if ((int)$minNextcloudVersion >= 19) {
return 2;
}
} catch (\Exception $e) {
return 1;
}
return 2;
}
/**
* Write the signature of core
*
@ -271,14 +310,14 @@ class Checker {
*/
public function writeCoreSignature(X509 $certificate,
RSA $rsa,
$path) {
string $path) {
$coreDir = $path . '/core';
try {
$this->fileAccessHelper->assertDirectoryExists($coreDir);
$iterator = $this->getFolderIterator($path, $path);
$hashes = $this->generateHashes($iterator, $path);
$signatureData = $this->createSignatureData($hashes, $certificate, $rsa);
$signatureData = $this->createSignatureData($hashes, $certificate, $rsa, 2);
$this->fileAccessHelper->file_put_contents(
$coreDir . '/signature.json',
json_encode($signatureData, JSON_PRETTY_PRINT)
@ -316,8 +355,6 @@ class Checker {
throw new InvalidSignatureException('Signature data not found.');
}
$expectedHashes = $signatureData['hashes'];
ksort($expectedHashes);
$signature = base64_decode($signatureData['signature']);
$certificate = $signatureData['certificate'];
@ -343,10 +380,27 @@ class Checker {
$rsa->setMGFHash('sha512');
// See https://tools.ietf.org/html/rfc3447#page-38
$rsa->setSaltLength(0);
if(!$rsa->verify(json_encode($expectedHashes), $signature)) {
$version = 1;
if (isset($signatureData['version'])) {
$version = $signatureData['version'];
}
if ($version === 1) {
$expectedHashes = $signatureData['hashes'];
ksort($expectedHashes);
$expectedHashes = json_encode($expectedHashes);
}
if ($version === 2) {
$expectedHashes = $signatureData['hashes'];
}
if(!$rsa->verify($expectedHashes, $signature)) {
throw new InvalidSignatureException('Signature could not get verified.');
}
$expectedHashes = json_decode($expectedHashes, true);
// Fixes for the updater as shipped with ownCloud 9.0.x: The updater is
// replaced after the code integrity check is performed.
//