[Qemu-devel] [Bug 1809252] [NEW] Password authentication in FIPS-compliant mode

[Qemu-devel] [Bug 1809252] [NEW] Password authentication in FIPS-compliant mode

[Tomasz Barański]

Public bug reported:

The documentation states, that:

"The VNC protocol has limited support for password based authentication.
(...) Password authentication is not supported when operating in FIPS
140-2 compliance mode as it requires the use of the DES cipher."

Would it be possible for qemu to use a different cipher and re-enable
password as an option in VNC console? Is there a technical reason for
not using a stronger cipher?

** Affects: qemu
     Importance: Undecided
         Status: New


** Tags: fips vnc

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Title:
  Password authentication in FIPS-compliant mode

Status in QEMU:
  New

Bug description:
  The documentation states, that:

  "The VNC protocol has limited support for password based
  authentication. (...) Password authentication is not supported when
  operating in FIPS 140-2 compliance mode as it requires the use of the
  DES cipher."

  Would it be possible for qemu to use a different cipher and re-enable
  password as an option in VNC console? Is there a technical reason for
  not using a stronger cipher?

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Re: [Qemu-devel] [Bug 1809252] [NEW] Password authentication in FIPS-compliant mode

[Eric Blake]

On 12/20/18 6:59 AM, Tomasz Barański wrote:
> Public bug reported:
> 
> The documentation states, that:
> 
> "The VNC protocol has limited support for password based authentication.
> (...) Password authentication is not supported when operating in FIPS
> 140-2 compliance mode as it requires the use of the DES cipher."
> 
> Would it be possible for qemu to use a different cipher and re-enable
> password as an option in VNC console? Is there a technical reason for
> not using a stronger cipher?

The technical reason is that there are no other VNC endpoints out there 
that support a different cipher. The VNC protocol itself declares what 
all compliant servers/clients must use - and that spec is what makes the 
non-FIPS-compliant requirement.  You wouldn't have to patch just qemu, 
but every other VNC endpoint out there that you want to interoperate 
with a patched qemu.  But it's really not worth doing that when there 
are already better solutions available.  That is, rather than trying to 
fix VNC, just use an alternative protocol that doesn't have a baked-in 
authentication limitation in the first place - namely, Spice.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

[Qemu-devel] [Bug 1809252] Re: Password authentication in FIPS-compliant mode

[Daniel Berrange]

The VNC password authentication scheme is not extensible. It is
unfixably broken by design.

QEMU provides the SASL authentication scheme for VNC which allows for
strong authentication, when combined with the VeNCrypt authentication
scheme that uses TLS.

These extensions are supported by the gtk-vnc client used by remote-
viewer, virt-viewer, virt-manager, GNOME Boxes and more.  Other VNC
clients are also known to implement VeNCrypt, though SASL support is
less wide spread.

>From a QEMU POV, there's nothing more we need todo really - any
remaining gaps are client side.

** Changed in: qemu
       Status: New => Invalid

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You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1809252

Title:
  Password authentication in FIPS-compliant mode

Status in QEMU:
  Invalid

Bug description:
  The documentation states, that:

  "The VNC protocol has limited support for password based
  authentication. (...) Password authentication is not supported when
  operating in FIPS 140-2 compliance mode as it requires the use of the
  DES cipher."

  Would it be possible for qemu to use a different cipher and re-enable
  password as an option in VNC console? Is there a technical reason for
  not using a stronger cipher?

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1809252/+subscriptions

[Qemu-devel] [Bug 1809252] Re: Password authentication in FIPS-compliant mode

[Tomasz Barański]

I understand. Thank you, guys!

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https://bugs.launchpad.net/bugs/1809252

Title:
  Password authentication in FIPS-compliant mode

Status in QEMU:
  Invalid

Bug description:
  The documentation states, that:

  "The VNC protocol has limited support for password based
  authentication. (...) Password authentication is not supported when
  operating in FIPS 140-2 compliance mode as it requires the use of the
  DES cipher."

  Would it be possible for qemu to use a different cipher and re-enable
  password as an option in VNC console? Is there a technical reason for
  not using a stronger cipher?

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1809252/+subscriptions