From: Arno Wagner <arno@wagner.name>
To: dm-crypt@saout.de
Subject: Re: [dm-crypt] Exhaustive key reading seems to silently stop on error
Date: Fri, 11 Dec 2009 05:06:19 +0100 [thread overview]
Message-ID: <20091211040619.GA6979@tansi.org> (raw)
In-Reply-To: <4B2023F1.6050306@gmx.net>
Hmm. This seems to indeed be a bug.
I gather there is no code later that distinguishes
EOF and error and deals with the second possibility?
Arno
On Wed, Dec 09, 2009 at 11:25:53PM +0100, Nico R. wrote:
> Hello!
>
> Just a minute ago, I have subscribed to this list in order to let you
> know about what I have found in the cryptsetup code and which seems to
> be a bug to me.
>
> In lib/utils.c (line 450f. in cryptsetup-1.0.7; line 490f. in current
> SVN revision, r132, equal to r152), we see the following code:
>
> if(read(fd, pass + i, 1) != 1 || (newline_stop && pass[i] == '\n'))
> break;
>
> If I interpret that snipped (and its surroundings) correctly, the code
> will read until EOF *or* until an error occurs.
>
> If my interpretation is true, that code causes a problem: imagine a
> hardware failure while reading the key the first two times (for
> luksFormat/luksOpen). The read function returns -1 and sets errno to
> EIO. cryptsetup continues with a truncated key, it seems. On a later
> attempt to read the key (for luksOpen), the hardware failure is gone,
> and the key can be read completely. cryptsetup will not be able to open
> the encrypted partition anymore.
>
> Please correct me if I got the code wrong?????? :-)
>
> Thanks
> --
> Nico
>
> _______________________________________________
> dm-crypt mailing list
> dm-crypt@saout.de
> http://www.saout.de/mailman/listinfo/dm-crypt
--
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name
GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans
If it's in the news, don't worry about it. The very definition of
"news" is "something that hardly ever happens." -- Bruce Schneier
next prev parent reply other threads:[~2009-12-11 4:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-09 22:25 [dm-crypt] Exhaustive key reading seems to silently stop on error Nico R.
2009-12-11 4:06 ` Arno Wagner [this message]
2009-12-11 10:57 ` Nico R.
2009-12-11 11:59 ` Milan Broz
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