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From: Jordan Glover <Golden_Miller83@protonmail.ch>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: Stephen Hemminger <stephen@networkplumber.org>,
	Matthew Garrett <matthewgarrett@google.com>,
	"jmorris@namei.org" <jmorris@namei.org>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"dhowells@redhat.com" <dhowells@redhat.com>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Chun-Yi Lee <jlee@suse.com>, Kees Cook <keescook@chromium.org>,
	Andy Lutomirski <luto@amacapital.net>,
	Will Drewry <wad@chromium.org>
Subject: Re: [PATCH 23/27] bpf: Restrict kernel image access functions when the kernel is locked down
Date: Tue, 26 Mar 2019 13:54:40 +0000	[thread overview]
Message-ID: <dPp-BlyzEqZTTJfOrFzxSsFZj1eDOH4k4Lx7Qc0DGBdsRXPJHP-K5866dzAoZTvw4-GsBRHc4bfkL2zrajh8-KXWeR2B0pLIy0SIjK0-K5c=@protonmail.ch> (raw)
In-Reply-To: <1cfa7345-c807-db76-f50a-ea3ba70f07b2@iogearbox.net>

On Tuesday, March 26, 2019 12:00 AM, Daniel Borkmann <daniel@iogearbox.net> wrote:

> On 03/26/2019 12:42 AM, Stephen Hemminger wrote:
>
> > On Mon, 25 Mar 2019 15:09:50 -0700
> > Matthew Garrett matthewgarrett@google.com wrote:
> >
> > > From: David Howells dhowells@redhat.com
> > > There are some bpf functions can be used to read kernel memory:
> > > bpf_probe_read, bpf_probe_write_user and bpf_trace_printk. These allow
> > > private keys in kernel memory (e.g. the hibernation image signing key) to
> > > be read by an eBPF program and kernel memory to be altered without
> > > restriction.
>
> I'm not sure where 'kernel memory to be altered without restriction' comes
> from, but it's definitely a wrong statement.
>
> > > Completely prohibit the use of BPF when the kernel is locked down.
>
> In which scenarios will the lock-down mode be used? Mostly niche? I'm asking
> as this would otherwise break a lot of existing stuff ... I'd prefer you find
> a better solution to this than this straight -EPERM rejection.


AFAIK this change breaks IPAddressAllow/IPAddressDeny usage in systemd services
which makes them LESS secure.

https://www.freedesktop.org/software/systemd/man/systemd.resource-control.html
https://github.com/systemd/systemd/blob/04d7ca022843913fba5170c40be07acf2ab5902b/README#L96

Jordan

  reply	other threads:[~2019-03-26 13:54 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-25 22:09 [PULL REQUEST] Lockdown patches for 5.2 Matthew Garrett
2019-03-25 22:09 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-03-26  5:30   ` Matthew Garrett
2019-03-25 22:09 ` [PATCH 02/27] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-03-25 22:09 ` [PATCH 03/27] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-03-25 22:09 ` [PATCH 04/27] kexec_load: Disable at runtime if " Matthew Garrett
2019-03-25 22:09   ` Matthew Garrett
2019-03-25 22:09 ` [PATCH 05/27] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-03-25 22:09   ` Matthew Garrett
2019-03-25 22:09 ` [PATCH 06/27] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-03-25 22:09   ` Matthew Garrett
2019-03-25 22:09 ` [PATCH 07/27] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-03-25 22:09   ` Matthew Garrett
2019-03-25 22:09 ` [PATCH 08/27] hibernate: Disable when " Matthew Garrett
2019-03-25 22:09 ` [PATCH 09/27] uswsusp: " Matthew Garrett
2019-03-25 22:09 ` [PATCH 10/27] PCI: Lock down BAR access " Matthew Garrett
2019-03-25 22:09 ` [PATCH 11/27] x86: Lock down IO port " Matthew Garrett
2019-03-25 22:09 ` [PATCH 12/27] x86/msr: Restrict MSR " Matthew Garrett
2019-03-25 23:40   ` Thomas Gleixner
2019-03-25 22:09 ` [PATCH 13/27] ACPI: Limit access to custom_method " Matthew Garrett
2019-03-25 22:09 ` [PATCH 14/27] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-03-25 22:09 ` [PATCH 15/27] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-03-25 22:09   ` Matthew Garrett
2019-03-25 22:09 ` [PATCH 16/27] acpi: Disable APEI error injection " Matthew Garrett
2019-03-25 22:09 ` [PATCH 17/27] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-03-25 22:09 ` [PATCH 18/27] Lock down TIOCSSERIAL Matthew Garrett
2019-03-25 22:09 ` [PATCH 19/27] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-03-25 22:09 ` [PATCH 20/27] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-03-25 23:35   ` Steven Rostedt
2019-03-25 22:09 ` [PATCH 21/27] Lock down /proc/kcore Matthew Garrett
2019-03-25 22:09 ` [PATCH 22/27] Lock down kprobes Matthew Garrett
2019-03-26 12:29   ` Masami Hiramatsu
2019-03-26 17:41     ` Matthew Garrett
2019-03-26 22:47       ` Masami Hiramatsu
2019-03-25 22:09 ` [PATCH 23/27] bpf: Restrict kernel image access functions when the kernel is locked down Matthew Garrett
2019-03-25 23:42   ` Stephen Hemminger
2019-03-25 23:59     ` Stephen Hemminger
2019-03-26  0:00     ` Daniel Borkmann
2019-03-26 13:54       ` Jordan Glover [this message]
2019-03-26  0:10     ` Andy Lutomirski
2019-03-26 18:57       ` James Morris
2019-03-26 19:22         ` Andy Lutomirski
2019-03-28  3:15           ` James Morris
2019-03-28 18:07             ` Matthew Garrett
2019-03-28 19:23               ` James Morris
2019-03-28 20:08                 ` Matthew Garrett
2019-03-26 20:19         ` Matthew Garrett
2019-03-25 22:09 ` [PATCH 24/27] Lock down perf Matthew Garrett
2019-03-25 22:09 ` [PATCH 25/27] debugfs: Restrict debugfs when the kernel is locked down Matthew Garrett
2019-03-26  0:31   ` Greg Kroah-Hartman
2019-03-26  0:38     ` Matthew Garrett
2019-03-26  0:43       ` Greg Kroah-Hartman
2019-03-25 22:09 ` [PATCH 26/27] lockdown: Print current->comm in restriction messages Matthew Garrett
2019-03-25 22:09 ` [PATCH 27/27] kexec: Allow kexec_file() with appropriate IMA policy when locked down Matthew Garrett
2019-03-26 15:33   ` Mimi Zohar

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