[Qemu-devel] qemu-img do not verify encrytption

[Qemu-devel] qemu-img do not verify encrytption

[yue-kvm]

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i create qcow2 format image with -o encryption, and assign password.

but when i qemu-img info encryt.qcow2 ,  it display encryt.qcow2 info no master  what i input, even just hit enter.
the 'Password Authentication ' of qemu-img may be invalid.


thanks.




my steps:
--------
Create an encrypted disk

#qemu-img create -e -f qcow2 image.qcow2 10G

If you pass the option -e or -o encryption when you create an image, the resulting image will be encrypted, with an empty (blank) password – there is no option to set a password in a single step at the time of creation.

To set a password, again use qemu-img , but this time with the convert option

#qemu-img convert -e -O qcow2 image.qcow2 encrypted.qcow2

You will be asked to give a password twice. At the first prompt hit enter (as the password is blank), at the second prompt you will set the password for your resulting encrypted disk.

------------ 


[root@kvm images]# qemu-img info  encryped.qcow2
Disk image 'encryped.qcow2' is encrypted.
password: 
image: encryped.qcow2
file format: qcow2
virtual size: 8.0G (8589934592 bytes)
disk size: 136K
encrypted: yes
cluster_size: 65536



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Re: [Qemu-devel] qemu-img do not verify encrytption

[Stefan Hajnoczi]

On Thu, Mar 07, 2013 at 02:49:30PM +0800, yue-kvm wrote:
> i create qcow2 format image with -o encryption, and assign password.
> 
> but when i qemu-img info encryt.qcow2 ,  it display encryt.qcow2 info no master  what i input, even just hit enter.
> the 'Password Authentication ' of qemu-img may be invalid.

Don't worry, your data is encrypted.  The qemu-img info password check
is unnecessary because qcow2 metadata is unencrypted.

I didn't get a password prompt from qemu-img info on an encrypted qcow2
file using qemu.git/master.

Which version of qemu-img are you using?  Perhaps the unnecessary prompt
has been fixed in a later version.

Stefan

Re: [Qemu-devel] qemu-img do not verify encrytption

[yue-kvm]

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hi stefan:


[root@kvm ~]# qemu-img -V
qemu-img version 0.12.1, Copyright (c) 2004-2008 Fabrice Bellard


OS centos 6.3
thanks








At 2013-03-07 17:56:50,"Stefan Hajnoczi" <stefanha@gmail.com> wrote:
>On Thu, Mar 07, 2013 at 02:49:30PM +0800, yue-kvm wrote:
>> i create qcow2 format image with -o encryption, and assign password.
>> 
>> but when i qemu-img info encryt.qcow2 ,  it display encryt.qcow2 info no master  what i input, even just hit enter.
>> the 'Password Authentication ' of qemu-img may be invalid.
>
>Don't worry, your data is encrypted.  The qemu-img info password check
>is unnecessary because qcow2 metadata is unencrypted.
>
>I didn't get a password prompt from qemu-img info on an encrypted qcow2
>file using qemu.git/master.
>
>Which version of qemu-img are you using?  Perhaps the unnecessary prompt
>has been fixed in a later version.
>
>Stefan
>

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Re: [Qemu-devel] qemu-img do not verify encrytption

[陳韋任 (Wei-Ren Chen)]

On Thu, Mar 07, 2013 at 06:57:19PM +0800, yue-kvm wrote:
> hi stefan:
> 
> [root@kvm ~]# qemu-img -V
> qemu-img version 0.12.1, Copyright (c) 2004-2008 Fabrice Bellard

  Hrm..., 0.12 is too old, why don't you use newer version?

Regards,
chenwj

-- 
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj