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From: Andy Lutomirski <luto@kernel.org>
To: Matthew Garrett <mjg59@google.com>
Cc: Andy Lutomirski <luto@kernel.org>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	James Morris <jmorris@namei.org>,
	linux-security@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	David Howells <dhowells@redhat.com>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Network Development <netdev@vger.kernel.org>,
	Chun-Yi Lee <jlee@suse.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	LSM List <linux-security-module@vger.kernel.org>
Subject: Re: [PATCH V33 24/30] bpf: Restrict bpf when kernel lockdown is in confidentiality mode
Date: Sat, 29 Jun 2019 16:47:52 -0700	[thread overview]
Message-ID: <CALCETrUzGfB2EO0eUpan3b4qyUPmkTZ-7dMuLqu_bmnY-ry=SA@mail.gmail.com> (raw)
In-Reply-To: <CACdnJuuy7-tkj86njAqtdJ3dUMu-2T8a2y8DC3fMKBK0z9J6ag@mail.gmail.com>

On Fri, Jun 28, 2019 at 11:47 AM Matthew Garrett <mjg59@google.com> wrote:
>
> On Thu, Jun 27, 2019 at 4:27 PM Andy Lutomirski <luto@kernel.org> wrote:
> > They're really quite similar in my mind.  Certainly some things in the
> > "integrity" category give absolutely trivial control over the kernel
> > (e.g. modules) while others make it quite challenging (ioperm), but
> > the end result is very similar.  And quite a few "confidentiality"
> > things genuinely do allow all kernel memory to be read.
> >
> > I agree that finer-grained distinctions could be useful. My concern is
> > that it's a tradeoff, and the other end of the tradeoff is an ABI
> > stability issue.  If someone decides down the road that some feature
> > that is currently "integrity" can be split into a narrow "integrity"
> > feature and a "confidentiality" feature then, if the user policy knows
> > about the individual features, there's a risk of breaking people's
> > systems.  If we keep the fine-grained control, do we have a clear
> > compatibility story?
>
> My preference right now is to retain the fine-grained aspect of things
> in the internal API, simply because it'll be more annoying to add it
> back later if we want to. I don't want to expose it via the Lockdown
> user facing API for the reasons you've described, but it's not
> impossible that another LSM would find a way to do this reasonably.
> Does it seem reasonable to punt this discussion out to the point where
> another LSM tries to do something with this information, based on the
> implementation they're attempting?

I think I can get behind this, as long as it's clear to LSM authors
that this list is only a little bit stable.  I can certainly see the
use for the fine-grained info being available for auditing.

  reply	other threads:[~2019-06-29 23:48 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-21  1:19 [PATCH V33 00/30] Lockdown as an LSM Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 01/30] security: Support early LSMs Matthew Garrett
2019-06-21  3:21   ` Kees Cook
2019-06-21 19:26     ` Matthew Garrett
2019-06-21  5:23   ` Andy Lutomirski
2019-06-21 19:27     ` Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 02/30] security: Add a "locked down" LSM hook Matthew Garrett
2019-06-21  3:23   ` Kees Cook
2019-06-21 19:29     ` Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 03/30] security: Add a static lockdown policy LSM Matthew Garrett
2019-06-21  3:44   ` Kees Cook
2019-06-21 19:37     ` Matthew Garrett
2019-06-21 21:04       ` Matthew Garrett
2019-06-21 22:31   ` Mimi Zohar
2019-06-21  1:19 ` [PATCH V33 04/30] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-06-21  3:46   ` Kees Cook
2019-06-21  1:19 ` [PATCH V33 05/30] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 06/30] kexec_load: Disable at runtime if " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 07/30] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 08/30] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 09/30] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 10/30] hibernate: Disable when " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 11/30] uswsusp: " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 12/30] PCI: Lock down BAR access " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 13/30] x86: Lock down IO port " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 14/30] x86/msr: Restrict MSR " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 15/30] ACPI: Limit access to custom_method " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 16/30] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 17/30] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 18/30] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 19/30] Lock down TIOCSSERIAL Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 20/30] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 21/30] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-06-26 12:46   ` Steven Rostedt
2019-06-21  1:19 ` [PATCH V33 22/30] Lock down /proc/kcore Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 23/30] Lock down tracing and perf kprobes when in confidentiality mode Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 24/30] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-06-21  5:22   ` Andy Lutomirski
2019-06-21 20:05     ` Matthew Garrett
2019-06-26 20:22     ` James Morris
2019-06-27  0:57       ` Andy Lutomirski
2019-06-27 14:35         ` Stephen Smalley
2019-06-27 18:06           ` James Morris
2019-06-27 20:16             ` Stephen Smalley
2019-06-27 23:16               ` Matthew Garrett
2019-06-27 23:23                 ` Andy Lutomirski
2019-06-27 23:27           ` Andy Lutomirski
2019-06-28 18:47             ` Matthew Garrett
2019-06-29 23:47               ` Andy Lutomirski [this message]
2019-06-21  1:19 ` [PATCH V33 25/30] Lock down perf when " Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 26/30] kexec: Allow kexec_file() with appropriate IMA policy when locked down Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 27/30] lockdown: Print current->comm in restriction messages Matthew Garrett
2019-06-21  4:09   ` Kees Cook
2019-06-21  1:19 ` [PATCH V33 28/30] debugfs: Restrict debugfs when the kernel is locked down Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 29/30] tracefs: Restrict tracefs " Matthew Garrett
2019-06-26 13:07   ` Steven Rostedt
2019-06-26 19:39     ` Matthew Garrett
2019-06-21  1:19 ` [PATCH V33 30/30] efi: Restrict efivar_ssdt_load " Matthew Garrett

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