Re: [PATCH 2.6.32 19/38] [PATCH 19/38] pagemap: hide physical addresses from non-privileged users

From: Willy Tarreau
Date: Mon Nov 30 2015 - 07:13:48 EST


On Mon, Nov 30, 2015 at 02:49:59PM +0300, Konstantin Khlebnikov wrote:
> On 30.11.2015 14:30, Willy Tarreau wrote:
> >+ /* do not disclose physical addresses: attack vector */
> >+ pm.show_pfn = !cap_capable(current, file->f_cred, CAP_SYS_ADMIN,
> >SECURITY_CAP_AUDIT);
> >+
>
> At first sight this is confusing... but correct. It really returns zero
> for success, unlike to new file_ns_capable which returns bool true.

Yes, it trapped me as well, the first attempt I made only allowed non-root
to read the pagemap!

> The rest looks good too.

OK thank you.

Willy

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