From: david.safford@gmail.com
To: Mimi Zohar <zohar@linux.ibm.com>,
Janne Karhunen <janne.karhunen@gmail.com>,
linux-integrity@vger.kernel.org,
linux-security-module <linux-security-module@vger.kernel.org>
Cc: Ken Goldman <kgold@linux.ibm.com>,
monty.wiseman@ge.com, Amir Goldstein <amir73il@gmail.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH v2] ima: export the measurement list when needed
Date: Wed, 12 Feb 2020 16:08:15 -0500 [thread overview]
Message-ID: <6b787049b965c8056d0e27360e2eaa8fa2f38b35.camel@gmail.com> (raw)
In-Reply-To: <1581462616.5125.69.camel@linux.ibm.com>
On Tue, 2020-02-11 at 18:10 -0500, Mimi Zohar wrote:
> On Tue, 2020-02-11 at 11:10 -0500, david.safford@gmail.com wrote:
> > <snip>
> >
> This new feature will require setting up some infrastructure for
> storing the partial measurement list(s) in order to validate a TPM
> quote. Userspace already can save partial measurement list(s) without
> any kernel changes. The entire measurement list does not need to be
> read each time. lseek can read past the last record previously read.
> The only new aspect is truncating the in kernel measurement list in
> order to free kernel memory.
This is a pretty important new feature.
A lot of people can't use IMA because of the memory issue.
Also, I really think we need to let administrators choose the tradeoffs
of keeping the list in memory, on a local file, or only on the
attestation server, as best fits their use cases.
>
> < snip>
>
> Until there is proof that the measurement list can be exported to a
> file before kexec, instead of carrying the measurement list across
> kexec, and a TPM quote can be validated after the kexec, there isn't a
> compelling reason for the kernel needing to truncate the measurement
> list.
If this approach doesn't work with all the kexec use cases, then it is
useless, and the ball is in my court to prove that it does. Fortunately
I have to test that anyway for the coming TLV support.
Working on it...
dave
> Mimi
>
next prev parent reply other threads:[~2020-02-12 21:08 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200108111743.23393-1-janne.karhunen@gmail.com>
[not found] ` <CAE=NcrZrbRinOAbB+k1rjhcae3nqfJ8snC_EnY8njMDioM7=vg@mail.gmail.com>
2020-02-06 14:13 ` [PATCH v2] ima: export the measurement list when needed Mimi Zohar
2020-02-10 8:04 ` Janne Karhunen
2020-02-10 15:26 ` Mimi Zohar
2020-02-10 18:18 ` david.safford
2020-02-10 20:24 ` Mimi Zohar
2020-02-11 8:06 ` Janne Karhunen
2020-02-11 16:10 ` david.safford
2020-02-11 23:10 ` Mimi Zohar
2020-02-12 21:08 ` david.safford [this message]
2020-02-13 1:03 ` Mimi Zohar
2020-02-13 6:41 ` Janne Karhunen
2020-02-18 15:36 ` Mimi Zohar
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