Re: [PATCH v3] fs: introduce pipe-only dump mode suid_dumpable=3

[Kees Cook]

On Fri, Jun 22, 2012 at 3:20 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, 22 Jun 2012 15:07:45 -0700
> Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
>> mode=2 to disk _should_ break, is my point.
>
> And my point is that we should at least tell people that we broke it.
> I don't believe that returning an EINVAL from the write() is
> sufficient.  Because it introduces a high risk that people will run
> misconfigured systems for lengthy periods and it will cause them to
> have to do a *lot* of work once they discover that their system is
> misbehaving.
>
> So if we really really must instabreak back-compatibility, we should
> shout loudly into syslog about it: tell people that their system is
> broken and tell them what to do about it.
>
> And we should explain and justify this extraordinary action in the
> patch changelog.

Okay, sounds good. Should mode 3 added with mode 2 removed, or just
drop the dangerous behavior from mode 2? I will be loud in either
situation (e.g. with mode 3, setting mode 2 shouts, or when attempt to
write to disk in mode 2, shout).

-Kees

-- 
Kees Cook
Chrome OS Security
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