Re: [PATCH net] packet: packet_getname_spkt: make sure string is always 0-terminated

[Ben Hutchings <bhutchings@solarflare.com>]

On Thu, 2013-06-13 at 18:05 +0100, Ben Hutchings wrote:
> On Thu, 2013-06-13 at 01:38 -0700, David Miller wrote:
> > From: Daniel Borkmann <dborkman@redhat.com>
> > Date: Wed, 12 Jun 2013 16:02:27 +0200
> > 
> > > uaddr->sa_data is exactly of size 14, which is hard-coded here and
> > > passed as a size argument to strncpy(). A device name can be of size
> > > IFNAMSIZ (== 16), meaning we might leave the destination string
> > > unterminated. Thus, use strlcpy() and also sizeof() while we're
> > > at it. We need to memset the data area beforehand, since strlcpy
> > > does not padd the remaining buffer with zeroes for user space, so
> > > that we do not possibly leak anything.
> > > 
> > > Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
> > 
> > Applied, and queued up for -stable, thanks.
> 
> I don't think this should be applied anywhere.  Dropping support for
> 14-character device names is a regression.

...not that this actually prevents binding to 14-character device names;
it just means the name is then not reported back correctly.  Whatever,
it is a regression.  The fact that a 14-character name is not null-
terminated should be documented instead (I'm not sure where).

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.