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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Zubin Mithra <zsm@chromium.org>, stable <stable@vger.kernel.org>,
	groeck@chromium.org, Gen Zhang <blackgod016574@gmail.com>,
	Darren Hart <dvhart@infradead.org>,
	Andy Shevchenko <andy@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>
Subject: Re: 4e78921ba4dd ("efi/x86/Add missing error handling to old_memmap 1:1 mapping code")
Date: Tue, 4 Jun 2019 09:46:24 +0200	[thread overview]
Message-ID: <20190604074624.GA6840@kroah.com> (raw)
In-Reply-To: <CAKv+Gu8VioGy1h8n0zKAqj+m_PBZdRU+BmJDH7=D7=iEiKRpgw@mail.gmail.com>

On Tue, Jun 04, 2019 at 09:38:27AM +0200, Ard Biesheuvel wrote:
> On Tue, 4 Jun 2019 at 00:38, Zubin Mithra <zsm@chromium.org> wrote:
> >
> > Hello,
> >
> > CVE-2019-12380 was fixed in the upstream linux kernel with the commit :-
> > * 4e78921ba4dd ("efi/x86/Add missing error handling to old_memmap 1:1 mapping code")
> >
> > Could the patch be applied in order to v4.19.y?
> >
> > Tests run:
> > * Chrome OS tryjob
> >
> 
> Unless I am missing something, it seems to me that there is some
> inflation going on when it comes to CVE number assignments.
> 
> The code in question only affects systems that are explicitly booted
> with efi=old_map, and the memory allocation occurs so early during the
> boot sequence that even if we fail and handle it gracefully, it is
> highly unlikely that we can get to a point where the system is usable
> at all.
> 
> Does Chrome OS boot in EFI mode? Does it use efi=old_map? Is the
> kernel built with 5 level paging enabled? Did you run it on 5 level
> paging hardware?
> 
> Or is this just a tick the box exercise?
> 
> Also, I am annoyed (does it show? :-))  that nobody mentioned the CVE
> at any point when the patch was under review (not even privately)

CVEs are almost always asked for _after_ the patch is merged, as the
average fix-to-CVE request timeframe is -100 days.

Also, for the kernel, CVEs almost mean nothing, so if this really isn't
an issue, I'll not backport this.

And I really doubt that any chromeos device has 5 level page tables just
yet :)

thanks,

greg k-h

  reply	other threads:[~2019-06-04  7:46 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-03 22:38 4e78921ba4dd ("efi/x86/Add missing error handling to old_memmap 1:1 mapping code") Zubin Mithra
2019-06-04  7:38 ` Ard Biesheuvel
2019-06-04  7:46   ` Greg Kroah-Hartman [this message]
2019-06-04  8:52     ` Guenter Roeck
2019-06-04  9:03       ` Ard Biesheuvel
2019-06-04  9:09       ` Greg Kroah-Hartman
2019-06-04 12:34 ` Greg KH
2019-06-04 13:39   ` Ard Biesheuvel
2019-06-04 13:45     ` Greg KH
2019-06-04 13:47       ` Ard Biesheuvel
2019-06-04 16:38     ` Zubin Mithra

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