Re: [PATCH] decnet: fix shutdown parameter checking

[Steven Whitehouse]

Hi,

On Fri, 2012-08-31 at 15:57 -0400, David Miller wrote:
> From: Steven Whitehouse <swhiteho@xxxxxxxxxx>
> Date: Mon, 27 Aug 2012 10:16:41 +0100
> 
> > On Sun, 2012-08-26 at 22:37 -0400, Xi Wang wrote:
> >> The allowed value of "how" is SHUT_RD/SHUT_WR/SHUT_RDWR (0/1/2),
> >> rather than SHUTDOWN_MASK (3).
> >> 
> >> Signed-off-by: Xi Wang <xi.wang@xxxxxxxxx>
> > Acked-by: Steven Whitehouse <swhiteho@xxxxxxxxxx>
> 
> Applied to net-next.
> 
> > Although it could be argued that we should also continue to accept the
> > value 3 just in case there is any userland software out there which
> > sends that value,
> 
> True, but this is a rather standard BSD socket interface with a very
> specific small set of legitimate input parameters.  Allowing
> deviation, even for compatability for specific protocols, is largely
> unwise.

Yes, I'd agree on the whole, and certainly if this was a recent
addition. However since this code has been around for somewhere close to
16 years now, I'd say that means that either (a) nobody calls shutdown
for DECnet or (b) existing users are buggy too.

We do have a precedent for this kind of compatibility, such as the AX.25
use of SOCK_SEQPACKET.

However, I'm not overly worried and we'll soon know if it will cause any
problems or not,

Steve.



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