"Daniel P. Berrange" <berra...@redhat.com> writes: > On Tue, Jul 31, 2012 at 02:52:07PM -0500, Anthony Liguori wrote: >> Paul Moore <pmo...@redhat.com> writes: >> >> > On Friday, June 08, 2012 05:38:12 PM Paul Moore wrote: >> >> FIPS 140-2 requires disabling certain ciphers, including DES, which is >> >> used >> >> by VNC to obscure passwords when they are sent over the network. The >> >> solution for FIPS users is to disable the use of VNC password auth when >> >> the >> >> host system is operating in FIPS mode. >> >> >> >> This patch causes QEMU to emit a message to stderr when the host system is >> >> running in FIPS mode and a VNC password was specified on the commend line. >> >> If the system is not running in FIPS mode, or is running in FIPS mode but >> >> VNC password authentication was not requested, QEMU operates normally. >> >> >> >> Signed-off-by: Paul Moore <pmo...@redhat.com> >> > >> > Hi Anthony, >> > >> > Any word on this patch? Other than Daniel Berrange's reviewed-by tag, the >> > discussion of the v4 patch has been quiet and I think we addressed all the >> > other remaining issues in the discussion attached to the v2 patch >> > posting. >> >> I asked for the specific language in FIPS mandating this. I don't see >> any other VNC server implementing a check like this. I would rather do >> this in a more user friendly fashion like make it a config file option >> that a user can set while in fips mode. > > The FIPS standard doesn't refer to particular applications like VNC. > As Paul says earlier, FIP 140-2 requires that DES (and certain other > ciphers) not be used in any applications which are running in a FIPS > compliant environment. Since VNC auth uses DES, this auth scheme > cannot be permitted in a FIPS environment.
OpenSSL requires an explicit function call to enable fips mode--FIPS_mode_set(). It's not something that happens unconditionally behind the scenes. From talking to some folks here, it seems like an -enable-fips option would meet the requirements of FIPS. > The reason no other VNC server does this is almost certainly because > none of their developers have ever tried to have their code work in > a FIPS environment, so I don't think that's a relevant comparison. > > I'm not really sure what addding more configuration options gains > us here. The choice of auth mode is already configurable. This patch > is about ensuring that the user is not allowed to configure it, if > FIPS mode is in effect (as indicated by the kernels syfs tunable). > So in fact adding config params doesn't really address this. Disabling options unconditionally based on a magic kernel parameter is fundamentally wrong. If a user wants QEMU to participate in FIPS, it should explicitly ask QEMU to. Since OpenSSL also does this, there seems to be ample precedence for it. > The proposed patch is already very straightforward, is using the > official interface exposed by the upstream kernel to userspace & > has negligable maintenence burden IMHO. It's not QEMU's role to enforce security policy. Unconditionally disabling features goes against a very basic architectural assumption in QEMU. >From what I'm told, there's nothing in FIPS that prevents us from masking this behavior behind a command line option. And I think that's the right thing to do. Regards, Anthony Liguori > > Regards, > Daniel > -- > |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| > |: http://libvirt.org -o- http://virt-manager.org :| > |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| > |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
