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

[Kees Cook]

On Fri, Jun 22, 2012 at 12:55 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, 22 Jun 2012 12:24:13 -0700
> Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
>> The value
>> of suid_dumpable=2 is now historic, and attempting to set this sysctl
>> value returns -EINVAL.
>
> This sounds a bit harsh - will it not cause existing configurations to
> immediately break?  If so, would it not be better to retain the =2 mode
> for a while, and emit a nice warning when it is set?

I view it as a security vulnerability, so I'd rather see it
eliminated. I see "=1" as a security vulnerability too, but at least
that's well-known to be a bad idea. The "=2" mode has been assumed to
be safe, but it isn't.

-Kees

-- 
Kees Cook
Chrome OS Security
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