From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tyler Hicks <tyhicks@canonical.com>
Subject: Re: Key derivation and passprhase wrapping
Date: Fri, 29 Jan 2016 16:57:11 -0600
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To: Wiebe Cazemier <wiebe@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
> >=20
> > I think I missed an important bit. I was looking at ecryptfs-wrap-passp=
hrase,
> > which makes you supply the FEK and FEKEK, but ecryptfs-setup-private
> > actually already uses a random passphrase:
> >=20
> > -m, --mountpass MOUNTPASS
> >     Passphrase for mounting the ecryptfs directory, default is 16 bytes=
 from
> >     /dev/urandom if omitted
> >=20
>=20
> I do see an issue though. The bash script says:
>=20
>   random_data=3D`head -c 16000 /dev/urandom | od -x` || error_testing "$t=
emp" "$(gettext 'Could not generate random data')"
>=20
> But when urandom can't be read (doesn't exist, no file handles, whatever):
>=20
>   random_data=3D`head -c 16000 /dev/urando | od -x` || echo "fail"
>   head: cannot open =E2=80=98/dev/urando=E2=80=99 for reading: No such fi=
le or directory
>=20
> Note, no 'fail' and $? =3D=3D 0. And:
>=20
>   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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