linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Daniel Borkmann <daniel@iogearbox.net>
To: Stephen Hemminger <stephen@networkplumber.org>,
	Matthew Garrett <matthewgarrett@google.com>
Cc: jmorris@namei.org, linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org, dhowells@redhat.com,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	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 01:00:29 +0100	[thread overview]
Message-ID: <1cfa7345-c807-db76-f50a-ea3ba70f07b2@iogearbox.net> (raw)
In-Reply-To: <20190325164221.5d8687bd@shemminger-XPS-13-9360>

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.

>> Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
>> Signed-off-by: David Howells <dhowells@redhat.com>
>> cc: netdev@vger.kernel.org
>> cc: Chun-Yi Lee <jlee@suse.com>
>> cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
>> Cc: Daniel Borkmann <daniel@iogearbox.net>
>> Signed-off-by: Matthew Garrett <matthewgarrett@google.com>
> 
> Wouldn't this mean that Seccomp won't work in locked down mode?
> 


  parent reply	other threads:[~2019-03-26  0:00 UTC|newest]

Thread overview: 50+ 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 ` [PATCH 05/27] Copy secure_boot flag in boot params across kexec reboot 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 ` [PATCH 07/27] kexec_file: Restrict at runtime if the kernel is locked down 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 ` [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 [this message]
2019-03-26 13:54       ` Jordan Glover
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1cfa7345-c807-db76-f50a-ea3ba70f07b2@iogearbox.net \
    --to=daniel@iogearbox.net \
    --cc=alexei.starovoitov@gmail.com \
    --cc=dhowells@redhat.com \
    --cc=jlee@suse.com \
    --cc=jmorris@namei.org \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=luto@amacapital.net \
    --cc=matthewgarrett@google.com \
    --cc=netdev@vger.kernel.org \
    --cc=stephen@networkplumber.org \
    --cc=wad@chromium.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).