linux-kernel - Re: [PATCH 1/2] efi+tpm: Don't access event->count when it isn't mapped.

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20190827110344.4uvjppmkkaeex3mk@linux.intel.com>
Date:   Tue, 27 Aug 2019 14:03:44 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Matthew Garrett <mjg59@...gle.com>
Cc:     Peter Jones <pjones@...hat.com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Roberto Sassu <roberto.sassu@...wei.com>,
        Bartosz Szczepanek <bsz@...ihalf.com>,
        Lyude Paul <lyude@...hat.com>,
        linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] efi+tpm: Don't access event->count when it isn't
 mapped.

On Mon, Aug 26, 2019 at 10:44:31AM -0700, Matthew Garrett wrote:
> On Mon, Aug 26, 2019 at 9:28 AM Jarkko Sakkinen
> <jarkko.sakkinen@...ux.intel.com> wrote:
> >
> > On Mon, Aug 26, 2019 at 11:30:27AM -0400, Peter Jones wrote:
> > > Some machines generate a lot of event log entries.  When we're
> > > iterating over them, the code removes the old mapping and adds a
> > > new one, so once we cross the page boundary we're unmapping the page
> > > with the count on it.  Hilarity ensues.
> > >
> > > This patch keeps the info from the header in local variables so we don't
> > > need to access that page again or keep track of if it's mapped.
> > >
> > > Signed-off-by: Peter Jones <pjones@...hat.com>
> > > Tested-by: Lyude Paul <lyude@...hat.com>
> >
> > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> Acked-by: Matthew Garrett <mjg59@...gle.com>
> 
> Jarkko, these two should probably go to 5.3 if possible - I
> independently had a report of a system hitting this issue last week
> (Intel apparently put a surprising amount of data in the event logs on
> the NUCs).

OK, I can try to push them. I'll do PR today.

/Jarkko