Re: [PATCH 2/3] block: fail SCSI passthrough ioctls on partition devices

[Willy Tarreau]

On Thu, Dec 22, 2011 at 10:37:56AM -0800, Linus Torvalds wrote:
> On Thu, Dec 22, 2011 at 10:02 AM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> > Linux allows executing the SG_IO ioctl on a partition or even on an
> > LVM volume, and will pass the command to the underlying block device.
> > This is well-known, but it is also a large security problem when (via
> > Unix permissions, ACLs, SELinux or a combination thereof) a program or
> > user needs to be granted access to a particular partition or logical
> > volume but not to the full device.
> 
> So who actually *does* this in practice?

I've seen this in the past when mtools were used a lot to access FAT
partitions on dual-boot systems. I've also seen it with vmware, where
a user is allowed to boot the other OS within vmware without rebooting.
But granted this is not the most common scheme.

Willy

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