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Re: [Qemu-devel] [Xen-devel] [PATCH] Do not emulate a floppy drive when
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [Xen-devel] [PATCH] Do not emulate a floppy drive when -nodefaults |
Date: |
Thu, 14 May 2015 16:44:00 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 |
On 14/05/2015 16:39, Stefano Stabellini wrote:
> On Thu, 14 May 2015, Paolo Bonzini wrote:
>> On 14/05/2015 15:25, Sander Eikelenboom wrote:
>>> I tend to kindly disagree if you look at the broader perspective, yes it's
>>> could
>>> be a storm in a tea cup, but there seems to be a pattern.
>>>
>>> From a "cmdline user" / "platform emulation" point of view i can imagine
>>> that some sort of
>>> auto configuration / bundling in platforms is necessary (to limit the
>>> length of
>>> the cmdline to be supplied).
>>>
>>> But from a library / toolstack point of view it's quite nasty if *all* more
>>> or
>>> less obscure options have to actively disabled. It's quite undoable, not to
>>> mention what
>>> happens when new ones get added.
>>
>> Where do you stop?
>
> At this stage I would be happy enough if no floppy drives were actually
> emulated when the user asks for none.
Floppy drives aren't being emulated; the controller is. Same for IDE,
so why single out the FDD controller?
> Sure, but it is harder to write a device emulator in a secure fashion
> than a brand new PV interface, that can be designed with security in
> mind from scratch. The number of VM escaping CVEs affecting Xen PV
> interfaces is extremely low, I think it was just two since the start of
> the project.
Sure; OTOH, treating hypervisor and QEMU escapes would be very silly, if
QEMU has been properly protected (through any combination of stubdoms,
LSM, seccomp, ...).
Paolo
>
>
>>> From this PoV it would be better to have to actively enable all the stuff
>>> you want.
>>>
>>> At least Xen seemed to have taken the "no-defaults" as the best option to
>>> get
>>> there so far, but that doesn't seem to
>>>
>>> It's not the first CVE that has come from this "you have to actively
>>> disable all
>>> you don't want to happen" and probably won't be the last.
>>>
>>> So a "-no-defaults-now-for-real" option/mode for libraries / toolstacks,
>>> that
>>> requires them to be very verbose, explicit and specific in what they
>>> actually
>>> want, could be valuable.
>>
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, (continued)
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Michael S. Tsirkin, 2015/05/14
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Markus Armbruster, 2015/05/14
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Paolo Bonzini, 2015/05/14
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Markus Armbruster, 2015/05/14
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Daniel P. Berrange, 2015/05/14
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Paolo Bonzini, 2015/05/14
- Re: [Qemu-devel] [Xen-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Sander Eikelenboom, 2015/05/14
- Re: [Qemu-devel] [Xen-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Daniel P. Berrange, 2015/05/14
- Re: [Qemu-devel] [Xen-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Paolo Bonzini, 2015/05/14
- Re: [Qemu-devel] [Xen-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Stefano Stabellini, 2015/05/14
- Re: [Qemu-devel] [Xen-devel] [PATCH] Do not emulate a floppy drive when -nodefaults,
Paolo Bonzini <=
- Re: [Qemu-devel] [Xen-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Stefano Stabellini, 2015/05/14
- Re: [Qemu-devel] [Xen-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Michael S. Tsirkin, 2015/05/14
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Michael S. Tsirkin, 2015/05/14
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, John Snow, 2015/05/14
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Markus Armbruster, 2015/05/15
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Paolo Bonzini, 2015/05/15
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Stefano Stabellini, 2015/05/15
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Kevin Wolf, 2015/05/18
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Michael S. Tsirkin, 2015/05/14
- Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults, Paolo Bonzini, 2015/05/14