From: Pavel Machek <pavel@ucw.cz>
To: kernel list <linux-kernel@vger.kernel.org>,
security@kernel.org, linux-bluetooth@vger.kernel.org,
johan.hedberg@gmail.com, marcel@holtmann.org
Subject: (Small) bias in generation of random passkeys for pairing
Date: Wed, 19 Jun 2019 18:24:56 +0200 [thread overview]
Message-ID: <20190619162456.GA9096@amd> (raw)
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Hi!
There's a (small) bias in passkey generation in bluetooth:
get_random_bytes(&passkey, sizeof(passkey));
passkey %= 1000000;
put_unaligned_le32(passkey, smp->tk);
(there are at least two places doing this).
All passkeys are not of same probability, passkey "000000" is more
probable than "999999", but difference is small.
Do we care?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next reply other threads:[~2019-06-19 16:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-19 16:24 Pavel Machek [this message]
2019-06-20 12:00 ` (Small) bias in generation of random passkeys for pairing Stefan Seyfried
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