netdev - Re: [PATCH 08/17] can: add ISO 15765-2:2016 transport protocol

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Sat, 10 Oct 2020 08:44:21 -0700
From:   Jakub Kicinski <kuba@...nel.org>
To:     Oliver Hartkopp <socketcan@...tkopp.net>
Cc:     Marc Kleine-Budde <mkl@...gutronix.de>, netdev@...r.kernel.org,
        davem@...emloft.net, linux-can@...r.kernel.org,
        kernel@...gutronix.de
Subject: Re: [PATCH 08/17] can: add ISO 15765-2:2016 transport protocol

On Sat, 10 Oct 2020 16:29:06 +0200 Oliver Hartkopp wrote:
> >> diff --git a/net/can/Kconfig b/net/can/Kconfig
> >> index 25436a715db3..021fe03a8ed6 100644
> >> --- a/net/can/Kconfig
> >> +++ b/net/can/Kconfig
> >> @@ -55,6 +55,19 @@ config CAN_GW
> >>   
> >>   source "net/can/j1939/Kconfig"
> >>   
> >> +config CAN_ISOTP
> >> +	tristate "ISO 15765-2:2016 CAN transport protocol"
> >> +	default y  
> > 
> > default should not be y unless there is a very good reason.
> > I don't see such reason here. This is new functionality, users
> > can enable it if they need it.
> 
> Yes. I agree. But there is a good reason for it.
> The ISO 15765-2 protocol is used for vehicle diagnosis and is a *very* 
> common CAN bus use case.

More common than j1939? (Google uses words like 'widely used' and
'common' :)) To give you some perspective we don't enable Ethernet 
vlan support by default, vlans are pretty common, too.

> The config item only shows up when CONFIG_CAN is selected and then ISO 
> 15765-2 should be enabled too. I have implemented and maintained the 
> out-of-tree driver for ~12 years now and the people have real problems 
> using e.g. Ubuntu with signed kernel modules when they need this protocol.
> 
> Therefore the option should default to 'y' to make sure the common 
> distros (that enable CONFIG_CAN) enable ISO-TP too.

I understand the motivation, but Linus had pushed back on defaulting to
'y' many times over the years, please read this:

https://lkml.org/lkml/2012/1/6/354

This really must not pop up on his screen as default 'y' when he does
an oldconfig after pulling the networking tree..