From: zohar@linux.vnet.ibm.com (Mimi Zohar)
To: linux-security-module@vger.kernel.org
Subject: Firmware signing -- Re: [PATCH 00/27] security, efi: Add kernel lockdown
Date: Wed, 15 Nov 2017 14:56:57 -0500 [thread overview]
Message-ID: <1510775817.3711.315.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171115175246.GN729@wotan.suse.de>
On Wed, 2017-11-15 at 18:52 +0100, Luis R. Rodriguez wrote:
> On Wed, Nov 15, 2017 at 06:49:57AM -0500, Mimi Zohar wrote:
> > On Tue, 2017-11-14 at 21:50 +0100, Luis R. Rodriguez wrote:
> >
> > > Johannes made cfg80211 recently just use request_firmware() now via commit on
> > > linux-next 90a53e4432 ("cfg80211: implement regdb signature checking") [0] as
> > > he got tired of waiting firmware signing, but note he implemented a signature
> > > checking on its own so he open codes verify_pkcs7_signature() after the
> > > request_firmware() call. If we are happy to live with this, then so be it.
> > >
> > > [0] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=90a53e4432b12288316efaa5f308adafb8d304b0
> >
> > Johannes was tired of waiting? ?Commit 5a9196d "ima: add support for
> > measuring and appraising firmware" has been in the kernel since linux-
> > 3.17.
> >
> > The original firmware hook for verifying firmware signatures were
> > replaced with the common LSM pre and post kernel_read_file() hooks
> > in?linux-4.6.y.
> >
> > Even if you wanted to support firmware signature verification without
> > IMA-appraisal, it should be using the LSM hooks.
>
> request_firmware() uses kernel_read_file_from_path() underneath the hood,
> and so its used for both:
>
> /lib/firmware/regulatory.db
> /lib/firmware/regulatory.db.p7s
The firmware signature validation should occur as part of
kernel_read_file_from_path(), not as a stand alone verification.
Why not extend kernel_read_file_from_path() to pass the detached signature? ?Since the signature would only be used for the verification, there's no need to return the open file descriptor.
Or if you prefer, call kernel_read_file_from_path() for the detached signature first, and then call it again for the firmware with a pointer to the detached signature.
>
> The later only if CONFIG_CFG80211_REQUIRE_SIGNED_REGDB, which defaults
> to y anyway.
>
> What I meant was that net/wireless/reg.c now open codes firmware signature
> validation on its own rather than using a helper. IMA appraisal will still
> be used if enabled given kernel_read_file_from_path() is used.
>
> The open coding of the firmware signature check is what I wanted to highlight.
How are the keys in the CFG80211_EXTRA_REGDB_KEYDIR verified? ?The
call to key_create_or_update() with the KEY_ALLOC_BYPASS_RESTRICTION
option by-passes any requirement that the keys in this directory are
signed. ?This by-passes the concept of extending the secure boot
signature chain of trust. ?To safely validate the keys use the
restrict_link_by_builtin_trusted option.
Mimi
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next prev parent reply other threads:[~2017-11-15 19:56 UTC|newest]
Thread overview: 148+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-19 14:50 [PATCH 00/27] security, efi: Add kernel lockdown David Howells
2017-10-19 14:50 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image David Howells
2017-10-20 23:19 ` James Morris
2017-10-19 14:50 ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown David Howells
2017-10-19 17:20 ` Randy Dunlap
2017-10-19 22:12 ` David Howells
2017-11-07 17:39 ` Thiago Jung Bauermann
2017-11-07 22:56 ` David Howells
2017-10-19 14:50 ` [PATCH 03/27] Enforce module signatures if the kernel is locked down David Howells
2017-10-20 6:33 ` joeyli
2017-10-20 23:21 ` James Morris
2017-10-27 18:48 ` Mimi Zohar
2017-10-30 17:00 ` David Howells
2017-10-30 17:52 ` Mimi Zohar
2017-11-02 17:22 ` David Howells
2017-11-02 19:13 ` Mimi Zohar
2017-11-02 21:30 ` David Howells
2017-11-02 21:41 ` Mimi Zohar
2017-11-02 22:01 ` David Howells
2017-11-02 22:18 ` Mimi Zohar
2017-10-19 14:51 ` [PATCH 04/27] Restrict /dev/mem and /dev/kmem when " David Howells
2017-10-20 6:37 ` joeyli
2017-10-20 23:21 ` James Morris
2017-10-19 14:51 ` [PATCH 05/27] kexec: Disable at runtime if " David Howells
2017-10-20 6:38 ` joeyli
2017-10-20 23:22 ` James Morris
2017-10-19 14:51 ` [PATCH 06/27] Copy secure_boot flag in boot params across kexec reboot David Howells
2017-10-20 6:40 ` joeyli
2017-10-19 14:51 ` [PATCH 07/27] kexec_file: Disable at runtime if securelevel has been set David Howells
2017-10-20 23:26 ` James Morris
2017-10-23 15:54 ` Mimi Zohar
2017-10-26 7:42 ` joeyli
2017-10-26 14:17 ` Mimi Zohar
2017-10-27 19:30 ` Mimi Zohar
2017-10-27 19:32 ` Mimi Zohar
2017-10-28 8:34 ` joeyli
2017-10-29 22:26 ` Mimi Zohar
2017-10-30 9:00 ` David Howells
2017-10-30 12:01 ` Mimi Zohar
2017-10-26 15:02 ` David Howells
2017-10-26 15:46 ` Mimi Zohar
2017-10-30 15:49 ` David Howells
2017-10-30 16:43 ` Mimi Zohar
2017-11-02 17:00 ` David Howells
2017-10-26 14:51 ` David Howells
2017-11-02 17:29 ` David Howells
2017-10-19 14:51 ` [PATCH 08/27] hibernate: Disable when the kernel is locked down David Howells
2017-10-20 6:40 ` joeyli
2017-10-19 14:51 ` [PATCH 09/27] uswsusp: " David Howells
2017-10-20 6:41 ` joeyli
2017-10-20 23:29 ` James Morris
2017-10-19 14:51 ` [PATCH 10/27] PCI: Lock down BAR access " David Howells
2017-10-20 6:42 ` joeyli
2017-10-19 14:51 ` [PATCH 11/27] x86: Lock down IO port " David Howells
2017-10-20 6:43 ` joeyli
2017-10-19 14:52 ` [PATCH 12/27] x86/msr: Restrict MSR " David Howells
2017-10-20 6:43 ` joeyli
2017-10-20 18:09 ` Alan Cox
2017-10-20 20:48 ` David Howells
2017-10-21 4:39 ` joeyli
2017-10-23 14:49 ` David Howells
2017-10-25 14:03 ` joeyli
2017-10-19 14:52 ` [PATCH 13/27] asus-wmi: Restrict debugfs interface " David Howells
2017-10-20 6:44 ` joeyli
2017-10-19 14:52 ` [PATCH 14/27] ACPI: Limit access to custom_method " David Howells
2017-10-20 6:45 ` joeyli
2017-10-19 14:52 ` [PATCH 15/27] acpi: Ignore acpi_rsdp kernel param when the kernel has been " David Howells
2017-10-20 6:45 ` joeyli
2017-10-19 14:52 ` [PATCH 16/27] acpi: Disable ACPI table override if the kernel is " David Howells
2017-10-20 6:46 ` joeyli
2017-10-19 14:52 ` [PATCH 17/27] acpi: Disable APEI error injection " David Howells
2017-10-20 6:47 ` joeyli
2017-10-19 14:52 ` [PATCH 18/27] bpf: Restrict kernel image access functions when " David Howells
2017-10-19 22:18 ` Alexei Starovoitov
2017-10-20 2:47 ` joeyli
2017-10-20 8:08 ` David Howells
2017-10-20 15:57 ` jlee at suse.com
2017-10-20 16:03 ` David Howells
2017-10-20 16:43 ` jlee at suse.com
2017-10-23 14:53 ` David Howells
2017-10-25 7:07 ` joeyli
2017-10-19 22:48 ` David Howells
2017-10-19 23:31 ` Alexei Starovoitov
2017-11-09 17:15 ` David Howells
2017-10-19 14:52 ` [PATCH 19/27] scsi: Lock down the eata driver David Howells
2017-10-19 14:53 ` [PATCH 20/27] Prohibit PCMCIA CIS storage when the kernel is locked down David Howells
2017-10-19 14:53 ` [PATCH 21/27] Lock down TIOCSSERIAL David Howells
2017-10-19 14:53 ` [PATCH 22/27] Lock down module params that specify hardware parameters (eg. ioport) David Howells
2017-10-19 14:53 ` [PATCH 23/27] x86/mmiotrace: Lock down the testmmiotrace module David Howells
2017-10-19 14:53 ` [PATCH 24/27] debugfs: Disallow use of debugfs files when the kernel is locked down David Howells
2017-10-19 14:53 ` [PATCH 25/27] Lock down /proc/kcore David Howells
2017-10-21 2:11 ` James Morris
2017-10-23 14:56 ` David Howells
2017-10-19 14:53 ` [PATCH 26/27] efi: Add an EFI_SECURE_BOOT flag to indicate secure boot mode David Howells
2017-10-21 2:19 ` James Morris
2017-10-23 14:58 ` David Howells
2017-10-19 14:53 ` [PATCH 27/27] efi: Lock down the kernel if booted in " David Howells
2017-10-19 22:39 ` [PATCH 00/27] security, efi: Add kernel lockdown David Howells
2017-10-23 14:34 ` [PATCH 04/27] Restrict /dev/mem and /dev/kmem when the kernel is locked down David Howells
2017-10-24 10:48 ` Ethan Zhao
2017-10-24 14:56 ` David Howells
2017-11-02 22:01 ` [PATCH 00/27] security, efi: Add kernel lockdown Mimi Zohar
2017-11-02 22:04 ` Firmware signing -- " David Howells
2017-11-02 22:10 ` Mimi Zohar
2017-11-07 23:07 ` Luis R. Rodriguez
2017-11-08 6:15 ` AKASHI, Takahiro
2017-11-08 19:46 ` Luis R. Rodriguez
2017-11-09 1:48 ` AKASHI, Takahiro
2017-11-09 2:17 ` Mimi Zohar
2017-11-09 4:46 ` AKASHI, Takahiro
2017-11-10 13:37 ` Mimi Zohar
2017-11-11 2:32 ` Alan Cox
2017-11-13 11:49 ` Mimi Zohar
2017-11-13 17:42 ` Luis R. Rodriguez
2017-11-13 21:08 ` Alan Cox
2017-12-04 19:51 ` Luis R. Rodriguez
2017-12-07 15:32 ` Alan Cox
2017-11-13 21:44 ` David Howells
2017-11-13 22:09 ` Linus Torvalds
2017-11-14 0:20 ` Alan Cox
2017-11-14 12:21 ` Mimi Zohar
2017-11-14 12:38 ` Greg Kroah-Hartman
2017-11-14 13:17 ` Mimi Zohar
2017-11-14 17:34 ` Linus Torvalds
2017-11-14 19:58 ` Matthew Garrett
2017-11-14 20:18 ` Linus Torvalds
2017-11-14 20:31 ` Matthew Garrett
2017-11-14 20:35 ` Linus Torvalds
2017-11-14 20:37 ` Matthew Garrett
2017-11-14 20:50 ` Luis R. Rodriguez
2017-11-14 20:55 ` Matthew Garrett
2017-11-14 22:14 ` James Bottomley
2017-11-14 22:17 ` Matthew Garrett
2017-11-14 22:31 ` James Bottomley
2017-11-14 22:34 ` Matthew Garrett
2017-11-15 11:49 ` Mimi Zohar
2017-11-15 17:52 ` Luis R. Rodriguez
2017-11-15 19:56 ` Mimi Zohar [this message]
2017-11-15 20:46 ` Luis R. Rodriguez
2017-11-16 0:05 ` Mimi Zohar
[not found] ` <20171205102757.GA12982@amd>
2017-12-07 23:02 ` Luis R. Rodriguez
2017-12-08 17:11 ` Alan Cox
2017-11-10 1:46 ` Luis R. Rodriguez
2017-11-10 13:45 ` Mimi Zohar
2017-11-13 18:50 ` Luis R. Rodriguez
2017-11-13 19:08 ` Luis R. Rodriguez
2017-11-08 20:01 ` Mimi Zohar
2017-11-08 20:09 ` Luis R. Rodriguez
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