linux-kernel - Re: [ 03/42] TTY: fix atime/mtime regression

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <u4k3nk6xbr.fsf@md.dent.med.uni-muenchen.de>
Date:	Tue, 30 Apr 2013 14:02:16 +0200
From:	Wolfram Gloger <wmglo@...t.med.uni-muenchen.de>
To:	linux-kernel@...r.kernel.org
CC:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	wmglo@...t.med.uni-muenchen.de
Subject: Re: [ 03/42] TTY: fix atime/mtime regression

Hi,

>To revert to the old behaviour while still preventing attackers to
>guess the password length, we update the timestamps in one-minute
>intervals by this patch.

Sorry if I miss something, but isn't this an issue that should be very
obviously fixed in user space?  Only user space knows whether the
atime/mtime updates on a device are security-sensitive or not.

The sshd process and/or the login process could easily perform randomly
timed, dummy utime() calls on the tty around and within the password
typing, making this attack unfeasible.  I faintly remember sshd _already
does this_ for the network packets anyway by exchanging dummy packets.

Regards,
Wolfram.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/