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Re: [PATCH] usb-storage: don't call utsname()
- From: Greg KH <greg at kroah dot com>
- To: Christoph Hellwig <hch at infradead dot org>
- Cc: Alan Stern <stern at rowland dot harvard dot edu>, Matthew Dharm <mdharm-usb at one-eyed-alien dot net>, "Frank Ch. Eigler" <fche at redhat dot com>, Adrian Bunk <bunk at kernel dot org>, USB Storage list <usb-storage at lists dot one-eyed-alien dot net>, Kernel development list <linux-kernel at vger dot kernel dot org>, "David S. Miller" <davem at sunset dot davemloft dot net>, systemtap at sources dot redhat dot com, Andrew Morton <akpm at linux-foundation dot org>, linux-cifs-client at lists dot samba dot org, linux-nfs at vger dot kernel dot org
- Date: Wed, 21 May 2008 12:35:17 -0700
- Subject: Re: [PATCH] usb-storage: don't call utsname()
- References: <20080521123700.GA8770@infradead.org> <Pine.LNX.4.44L0.0805211349480.3409-100000@iolanthe.rowland.org> <20080521180957.GA17598@kroah.com> <20080521185251.GA783@infradead.org>
On Wed, May 21, 2008 at 02:52:51PM -0400, Christoph Hellwig wrote:
> On Wed, May 21, 2008 at 11:09:57AM -0700, Greg KH wrote:
> > Why? With this change, if you change the version number, the file will
> > have to be rebuilt. Without the change, the file will not need to be
> > rebuilt, right?
>
> Because thanks to the container patches it utsname fields other than
> hostname can actually change at runtime now and you'll get races looking
> at them. And probably not the output you want if someone in your
> container changes the kernel version to trick applications.
So, do we now go and rip out all usages of utsname()->release and put
back the #define just because of the loonacy of containers?
No kernel should have to change it's version number to trick an
application, why would an application care about the version number to
start with? In the "enterprise kernel" world, version numbers have
little to no relevance on the functionality or features of the kernel,
so any check of something like this is sure to be wrong to start with.
thanks,
greg k-h