From: Jessica Yu <jeyu@kernel.org>
To: Matthew Garrett <mjg59@google.com>
Cc: James Morris <jmorris@namei.org>,
LSM List <linux-security-module@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
David Howells <dhowells@redhat.com>,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH V37 04/29] Enforce module signatures if the kernel is locked down
Date: Thu, 8 Aug 2019 12:01:00 +0200 [thread overview]
Message-ID: <20190808100059.GA30260@linux-8ccs> (raw)
In-Reply-To: <CACdnJusD_9W9tFqwKptDTA8fZU8HrSvsEQhKo0WS9QxLpgz5tA@mail.gmail.com>
+++ Matthew Garrett [01/08/19 13:42 -0700]:
>On Thu, Aug 1, 2019 at 7:22 AM Jessica Yu <jeyu@kernel.org> wrote:
>> Apologies if this was addressed in another patch in your series (I've
>> only skimmed the first few), but what should happen if the kernel is
>> locked down, but CONFIG_MODULE_SIG=n? Or shouldn't CONFIG_SECURITY_LOCKDOWN_LSM
>> depend on CONFIG_MODULE_SIG? Otherwise I think we'll end up calling
>> the empty !CONFIG_MODULE_SIG module_sig_check() stub even though
>> lockdown is enabled.
>
>Hm. Someone could certainly configure their kernel in that way. I'm
>not sure that tying CONFIG_SECURITY_LOCKDOWN_LSM to CONFIG_MODULE_SIG
>is the right solution, since the new LSM approach means that any other
>LSM could also impose the same policy. Perhaps we should just document
>this?
Hi Matthew,
If you're confident that a hard dependency is not the right approach,
then perhaps we could add a comment in the Kconfig (You could take a
look at the comment under MODULE_SIG_ALL in init/Kconfig for an
example)? If someone is configuring the kernel on their own then it'd
be nice to let them know, otherwise having a lockdown kernel without
module signatures would defeat the purpose of lockdown no? :-)
Thank you,
Jessica
next prev parent reply other threads:[~2019-08-08 10:01 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-31 22:15 [PATCH V37 00/29] security: Add support for locking down the kernel Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 01/29] security: Support early LSMs Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 02/29] security: Add a "locked down" LSM hook Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 03/29] security: Add a static lockdown policy LSM Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 04/29] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-08-01 14:21 ` Jessica Yu
2019-08-01 20:42 ` Matthew Garrett
2019-08-08 10:01 ` Jessica Yu [this message]
2019-08-08 18:31 ` Matthew Garrett
2019-08-08 22:43 ` James Morris
2019-08-09 20:59 ` [PATCH V39] " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 05/29] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 06/29] kexec_load: Disable at runtime if " Matthew Garrett
2019-07-31 22:15 ` Matthew Garrett
2019-07-31 22:15 ` Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 07/29] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-07-31 22:15 ` Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 08/29] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-07-31 22:15 ` Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 09/29] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-07-31 22:15 ` Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 10/29] hibernate: Disable when " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 11/29] PCI: Lock down BAR access " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 12/29] x86: Lock down IO port " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 13/29] x86/msr: Restrict MSR " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 14/29] ACPI: Limit access to custom_method " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 15/29] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 16/29] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-07-31 22:16 ` Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 17/29] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 18/29] Lock down TIOCSSERIAL Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 19/29] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-08-01 16:19 ` Jessica Yu
2019-08-01 20:44 ` Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 20/29] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 21/29] Lock down /proc/kcore Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 22/29] Lock down tracing and perf kprobes when in confidentiality mode Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 23/29] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 24/29] Lock down perf when " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 25/29] kexec: Allow kexec_file() with appropriate IMA policy when locked down Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 26/29] debugfs: Restrict debugfs when the kernel is " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 27/29] tracefs: Restrict tracefs " Matthew Garrett
2019-08-13 6:10 ` Marek Szyprowski
2019-08-13 7:21 ` Marek Szyprowski
2019-08-14 6:12 ` [PATCH] tracefs: Fix NULL pointer dereference when no lockdown is used Marek Szyprowski
2019-07-31 22:16 ` [PATCH V37 28/29] efi: Restrict efivar_ssdt_load when the kernel is locked down Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 29/29] lockdown: Print current->comm in restriction messages Matthew Garrett
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