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From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: David Howells <dhowells@redhat.com>
Cc: joeyli <jlee@suse.com>,
	linux-security-module@vger.kernel.org,
	gnomes@lxorguk.ukuu.org.uk, linux-efi@vger.kernel.org,
	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
	jforbes@redhat.com, Matthew Garrett <mjg59@google.com>
Subject: Re: [PATCH 07/27] kexec_file: Disable at runtime if securelevel has been set
Date: Mon, 30 Oct 2017 12:43:58 -0400
Message-ID: <1509381838.3583.134.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <32764.1509378584@warthog.procyon.org.uk>

On Mon, 2017-10-30 at 15:49 +0000, David Howells wrote:
> Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:
> 
> > Huh?!  With the "secure_boot" policy enabled on the boot command line,
> > IMA-appraisal would verify the kexec kernel image, firmware, kernel
> > modules, and custom IMA policy signatures.
> 
> What happens if the "secure_boot" policy isn't enabled on the boot command
> line?  Can you sum up both cases in a paragraph I can add to the patch
> description?

The other patch automatically enables "secure_boot" for lockdown mode.
So there is no need to specify "secure_boot" on the boot command line.
 Reordering the patches so that the other patch comes before any call
to is_ima_appraise_enabled() will simplify this patch description.

> > Other patches in this patch series need to be updated as well to check
> > if IMA-appraisal is enabled.
> 
> Which exactly?  I've added your "!is_ima_appraise_enabled() &&" line to
> kexec_file() and module_sig_check().  Anything else?

load_module(), which calls module_sig_check(), is called by both the
old and new kernel module syscalls.  IMA is only on the new syscall.
 Did you differentiate between the kernel module syscalls?

There doesn't seem to be any other patches affected.  That said, the
IMA "secure_boot" policy is more stringent than what you have without
it.  For example, with the "secure_boot" policy enabled, firwmware
needs to be signed as well.  At some point, we'll want to also require
the initramfs be signed as well.

Both methods work independently of each other, but there needs to be
better coordination for when both methods are enabled at the same time
(eg. are both signatures required?).

For testing purposes, you can use the same certs/signing_key to sign
the kexec image, kernel modules and firmware, by loading the
signing_key on the .ima keyring.  Using evmctl, sign the files
(eg. evmctl ima_sign -a sha256 -k certs/signing_key.pem  --imasig
/boot/<vmlinuz>).

Mimi

  reply index

Thread overview: 151+ 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 [this message]
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
2017-10-20 23:00         ` Alexei Starovoitov
2017-10-23 14:51         ` David Howells
2017-10-20 16:03       ` David Howells
2017-10-20 16:43         ` jlee
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
2017-11-15 20:46                                         ` Luis R. Rodriguez
2017-11-16  0:05                                           ` Mimi Zohar
2017-12-05 10:27                                 ` Pavel Machek
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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