On Tue, Feb 21, 2017 at 05:39:12PM +0000, Daniel P. Berrange wrote: > On Tue, Feb 21, 2017 at 05:21:46PM +0000, Ketan Nilangekar wrote: > > > > > > On 2/21/17, 5:59 AM, "Stefan Hajnoczi" <stefa...@gmail.com> wrote: > > > > On Mon, Feb 20, 2017 at 03:34:57AM -0800, ashish mittal wrote: > > > On Mon, Feb 20, 2017 at 3:02 AM, Stefan Hajnoczi <stefa...@gmail.com> > > wrote: > > > > On Sat, Feb 18, 2017 at 12:30:31AM +0000, Ketan Nilangekar wrote: > > > >> On 2/17/17, 1:42 PM, "Jeff Cody" <jc...@redhat.com> wrote: > > > >> > > > >> On Thu, Feb 16, 2017 at 02:24:19PM -0800, ashish mittal wrote: > > > >> > Hi, > > > >> > > > > >> > I am getting the following error with checkpatch.pl > > > >> > > > > >> > ERROR: externs should be avoided in .c files > > > >> > #78: FILE: block/vxhs.c:28: > > > >> > +QemuUUID qemu_uuid __attribute__ ((weak)); > > > >> > > > > >> > Is there any way to get around this, or does it mean that I > > would have > > > >> > to add a vxhs.h just for this one entry? > > > >> > > > > >> > > > >> I remain skeptical on the use of the qemu_uuid as a way to > > select the TLS > > > >> cert. > > > >> > > > >> [ketan] > > > >> Is there another identity that can be used for uniquely > > identifying instances? > > > >> The requirement was to enforce vdisk access to owner instances. > > > > > > > > The qemu_uuid weak attribute looks suspect. What is going to > > provide a > > > > strong qemu_uuid symbol? > > > > > > > > Why aren't configuration parameters like the UUID coming from the > > QEMU > > > > command-line? > > > > > > > > Stefan > > > > > > UUID will in fact come from the QEMU command line. VxHS is not doing > > > anything special here. It will just use the value already available to > > > qemu-kvm process. > > > > > > QemuUUID qemu_uuid; > > > bool qemu_uuid_set; > > > > > > Both the above are defined in vl.c. vl.c will provide the strong > > > symbol when available. There are certain binaries that do not get > > > linked with vl.c (e.g. qemu-img). The weak symbol will come into > > > affect for such binaries, and in this case, the default VXHS UUID will > > > get picked up. I had, in a previous email, explained how we plan to > > > use the default UUID. In the regular case, the VxHS controller will > > > not allow access to the default UUID (non qemu-kvm) binaries, but it > > > may choose to grant temporary access to specific vdisks for these > > > binaries depending on the workflow. > > > > That idea sounds like a security problem. During this time window > > anyone could use the default UUID to access the data? > > > > Just make the UUID (or TLS client certificate file) a command-line > > parameter that qemu-system, qemu-img, and other tools accept (e.g. > > qemu-img via the --image-opts/--object syntax). > > > > [Ketan] > > Sounds fair. Would it be ok to take this up after the driver is > > merged for the upcoming QEMU release? > > I don't think we can merge code with known security flaws, particularly > if fixing these flaws will involve adding and/or changing command line > parameters for the block driver. >
We do support some protocols, such as gluster, that do not have robust authentication frameworks over tcp/ip. Of course, these protocols have been in as a driver for several years (and, gluster does support unix sockets). We seem to be establishing a rule for QEMU, that is "no new protocol drivers without secure authentication". That is a good thing. The existence of current protocol drivers that don't meet that criteria is potentially confusing for new contributors, however. (As a side note to myself -- this is probably a good thing to add to the wiki, if it is not there already). I think a non-secure scheme is worse than no scheme at all, because it becomes relied upon and promises something it cannot deliver. In that vein, would you object to a vxhs protocol driver that did no authentication at all (similar to gluster), or do you think the above rule is a new hard rule for protocol drivers? Jeff