From: Neil Horman <nhorman@tuxdriver.com>
To: Daniel Borkmann <dborkman@redhat.com>
Cc: davem@davemloft.net, linux-sctp@vger.kernel.org,
netdev@vger.kernel.org, Vlad Yasevich <vyasevich@gmail.com>
Subject: Re: [PATCH net 2/3] net: sctp: fix panic on duplicate ASCONF chunks
Date: Tue, 14 Oct 2014 22:58:34 -0400 [thread overview]
Message-ID: <20141015025833.GA6493@localhost.localdomain> (raw)
In-Reply-To: <543B0DD7.7000900@redhat.com>
On Mon, Oct 13, 2014 at 01:25:11AM +0200, Daniel Borkmann wrote:
> On 10/12/2014 03:42 AM, Neil Horman wrote:
> >On Sat, Oct 11, 2014 at 12:02:31AM +0200, Daniel Borkmann wrote:
> >>On 10/10/2014 05:39 PM, Neil Horman wrote:
> >>...
> >>>Is it worth adding a WARN_ON, to indicate that two ASCONF chunks have been
> >>>received with duplicate serials?
> >>
> >>Don't think so, as this would be triggerable from outside.
> >>
> >WARN_ON_ONCE then, per serial number?
>
> Sorry, but no. If someone seriously runs that in production and it
> triggers a WARN() from outside, admins will start sending us bug
> reports that apparently something with the kernel code is wrong.
>
> WARN() should only be used if we have some *internal* unexpected bug,
> but can still fail gracefully. This would neither be an actual code bug
> nor would it be an internally triggered one, plus we add unnecessary
> complexity to the code. Similarly, for those reasons we don't WARN()
> and throw a stack trace when we receive, say, an skb of invalid length
> elsewhere.
>
> I'd also like to avoid any additional pr_debug().
>
> I don't think people enable them in production, and if they really do,
> it's too late anyway as we already have received this chunk. If anything,
> I'd rather like to see debugging code further removed as we have already
> different facilities in the kernel for runtime debugging that are much
> more powerful.
What do you suggest then? It seems like this is a protocol error that an
administrator will want to be made aware of. I'm open to other options, but
just saying "no" isn't sufficient for me.
Neil
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next prev parent reply other threads:[~2014-10-15 2:58 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-09 20:55 [PATCH net 0/3] SCTP fixes Daniel Borkmann
2014-10-09 20:55 ` [PATCH net 1/3] net: sctp: fix skb_over_panic when receiving malformed ASCONF chunks Daniel Borkmann
2014-10-10 10:04 ` Joshua Kinard
2014-10-10 22:06 ` Daniel Borkmann
2014-10-10 14:48 ` Neil Horman
2014-10-09 20:55 ` [PATCH net 2/3] net: sctp: fix panic on duplicate " Daniel Borkmann
2014-10-10 15:39 ` Neil Horman
2014-10-10 22:02 ` Daniel Borkmann
2014-10-12 1:42 ` Neil Horman
2014-10-12 7:15 ` Vladislav Yasevich
2014-10-12 23:25 ` Daniel Borkmann
2014-10-15 2:58 ` Neil Horman [this message]
2014-10-15 23:13 ` Daniel Borkmann
2014-10-15 7:51 ` Vlad Yasevich
2014-10-09 20:55 ` [PATCH net 3/3] net: sctp: fix remote memory pressure from excessive queueing Daniel Borkmann
2014-10-14 16:46 ` [PATCH net 0/3] SCTP fixes David Miller
2014-10-15 3:06 ` Neil Horman
2014-10-15 4:21 ` David Miller
2014-10-15 20:20 ` Neil Horman
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