Messages in this thread |  | | Date | Thu, 26 Apr 2001 15:17:54 -0400 (EDT) | From | Alexander Viro <> | Subject | Re: [PATCH] SMP race in ext2 - metadata corruption. |
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On Thu, 26 Apr 2001, I wrote:
> On Thu, 26 Apr 2001, Linus Torvalds wrote: > > > I see the race, but I don't see how you can actually trigger it. > > > > Exactly _who_ does the "read from device" part? Somebody doing a > > "fsck" while the filesystem is mounted read-write and actively written > > to? Yeah, you'd get disk corruption that way, but you'll get it regardless > > of this bug.
OK, I think I've a better explanation now:
Suppose /dev/hda1 is owned by root.disks and permissions are 640. It is mounted read-write.
Process foo belongs to pfy.staff. PFY is included into disks, but doesn't have root. I claim that he should be unable to cause fs corruption on /dev/hda1.
Currently foo _can_ cause such corruption, even though it has nothing resembling write permissions for device in question.
IMO it is wrong. I'm not saying that it's a real security problem. I'm not saying that PFY is not idiot or that his actions make any sense. However, I think that situation when he can do that without write access to device is just plain wrong.
Does the above make sense? Al
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