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From: Tyler Hicks <tyhicks@canonical.com>
To: Wiebe Cazemier <wiebe@halfgaar.net>
Cc: ecryptfs@vger.kernel.org
Subject: Re: Key derivation and passprhase wrapping
Date: Fri, 29 Jan 2016 16:57:11 -0600	[thread overview]
Message-ID: <20160129225710.GD15683@boyd> (raw)
In-Reply-To: <497366096.234710.1453320193682.JavaMail.zimbra@halfgaar.net>

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On 2016-01-20 21:03:13, Wiebe Cazemier wrote:
> ----- Original Message -----
> > From: "Wiebe Cazemier" <wiebe@halfgaar.net>
> > To: "Tyler Hicks" <tyhicks@canonical.com>
> > Cc: ecryptfs@vger.kernel.org
> > Sent: Wednesday, 20 January, 2016 8:51:43 PM
> > Subject: Re: Key derivation and passprhase wrapping
> > 
> > I think I missed an important bit. I was looking at ecryptfs-wrap-passphrase,
> > which makes you supply the FEK and FEKEK, but ecryptfs-setup-private
> > actually already uses a random passphrase:
> > 
> > -m, --mountpass MOUNTPASS
> >     Passphrase for mounting the ecryptfs directory, default is 16 bytes from
> >     /dev/urandom if omitted
> > 
> 
> I do see an issue though. The bash script says:
> 
>   random_data=`head -c 16000 /dev/urandom | od -x` || error_testing "$temp" "$(gettext 'Could not generate random data')"
> 
> But when urandom can't be read (doesn't exist, no file handles, whatever):
> 
>   random_data=`head -c 16000 /dev/urando | od -x` || echo "fail"
>   head: cannot open ‘/dev/urando’ for reading: No such file or directory
> 
> Note, no 'fail' and $? == 0. And:
> 
>   echo $random_data
>   0000000

For completeness, we should mention that this is being tracked in
Launchpad:

 https://launchpad.net/bugs/1539553

Tyler

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      reply	other threads:[~2016-01-29 22:57 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <794484591.224591.1452104561446.JavaMail.zimbra@halfgaar.net>
2016-01-18 10:27 ` Key derivation and passprhase wrapping Wiebe Cazemier
2016-01-20  3:05   ` Tyler Hicks
2016-01-20 19:51     ` Wiebe Cazemier
2016-01-20 20:03       ` Wiebe Cazemier
2016-01-29 22:57         ` Tyler Hicks [this message]

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