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fix(authentication): Handle null or empty string password hash #36653

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Feb 20, 2023
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fix(authentication): Handle null or empty string password hash #36653

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2 changes: 1 addition & 1 deletion lib/private/Authentication/Token/PublicKeyTokenProvider.php
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Original file line number Diff line number Diff line change
Expand Up @@ -113,7 +113,7 @@ public function generateToken(string $token,
// We need to check against one old token to see if there is a password
// hash that we can reuse for detecting outdated passwords
$randomOldToken = $this->mapper->getFirstTokenForUser($uid);
$oldTokenMatches = $randomOldToken && $this->hasher->verify(sha1($password) . $password, $randomOldToken->getPasswordHash());
$oldTokenMatches = $randomOldToken && $randomOldToken->getPasswordHash() && $this->hasher->verify(sha1($password) . $password, $randomOldToken->getPasswordHash());
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Suggested change
$oldTokenMatches = $randomOldToken && $randomOldToken->getPasswordHash() && $this->hasher->verify(sha1($password) . $password, $randomOldToken->getPasswordHash());
$oldTokenMatches = $randomOldToken && ($pwHash = $randomOldToken->getPasswordHash()) && $this->hasher->verify(sha1($password) . $password, $pwHash);

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We don't do inline assignments in Nextcloud, also it's a just replacign a local member call here, so not sure it's worth the possible confusion.

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The problem is not to avoid the local call, it’s that you cannot know that getPasswordHash will return the same thing twice, so checking it returns a non-falsy value and then calling it againg and using it as an object is dangerous.
I’m not sure how is the pretty way to write this, and I do dislike the inline assignment, I used it to show the smalest change possible to show the idea.

psalm will yell at you for doing this kind of stuff. Especially when most of the time we only know the interface used and not the class.

Suggested change
$oldTokenMatches = $randomOldToken && $randomOldToken->getPasswordHash() && $this->hasher->verify(sha1($password) . $password, $randomOldToken->getPasswordHash());
if ($randomOldToken) {
$pwHash = $randomOldToken->getPasswordHash();
$oldTokenMatches = $pwHash && $this->hasher->verify(sha1($password) . $password, $pwHash);
} else {
$oldTokenMatches = false;
}

Or if PHP>=8:

Suggested change
$oldTokenMatches = $randomOldToken && $randomOldToken->getPasswordHash() && $this->hasher->verify(sha1($password) . $password, $randomOldToken->getPasswordHash());
$pwHash = $randomOldToken?->getPasswordHash();
$oldTokenMatches = $pwHash && $this->hasher->verify(sha1($password) . $password, $pwHash);

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The problem is not to avoid the local call, it’s that you cannot know that getPasswordHash will return the same thing twice

We have code like this with all our "Entities" all the time? How could the existing object change in the meantime?


$dbToken = $this->newToken($token, $uid, $loginName, $password, $name, $type, $remember);

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