From: David Howells <dhowells@redhat.com>
To: keyrings@vger.kernel.org
Cc: dhowells@redhat.com, matthew.garrett@nebula.com,
linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 04/16] efi: Lock down the kernel if booted in secure boot mode
Date: Wed, 16 Nov 2016 21:47:45 +0000 [thread overview]
Message-ID: <147933286579.19316.5236862894522647474.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk>
UEFI Secure Boot provides a mechanism for ensuring that the firmware will
only load signed bootloaders and kernels. Certain use cases may also
require that all kernel modules also be signed. Add a configuration option
that to lock down the kernel - which includes requiring validly signed
modules - if the kernel is secure-booted.
Signed-off-by: David Howells <dhowells@redhat.com>
---
arch/x86/Kconfig | 12 ++++++++++++
arch/x86/kernel/setup.c | 7 +++++++
kernel/module.c | 2 +-
3 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index bada636d1065..5b19997d88d0 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1786,6 +1786,18 @@ config EFI_MIXED
If unsure, say N.
+config EFI_SECURE_BOOT_LOCK_DOWN
+ def_bool n
+ depends on EFI
+ prompt "Lock down the kernel when UEFI Secure Boot is enabled"
+ ---help---
+ UEFI Secure Boot provides a mechanism for ensuring that the firmware
+ will only load signed bootloaders and kernels. Certain use cases may
+ also require that all kernel modules also be signed and that
+ userspace is prevented from directly changing the running kernel
+ image. Say Y here to automatically lock down the kernel when a
+ system boots with UEFI Secure Boot enabled.
+
config SECCOMP
def_bool y
prompt "Enable seccomp to safely compute untrusted bytecode"
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 9c337b0e8ba7..9521acce8378 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -69,6 +69,7 @@
#include <linux/crash_dump.h>
#include <linux/tboot.h>
#include <linux/jiffies.h>
+#include <linux/security.h>
#include <video/edid.h>
@@ -1160,6 +1161,12 @@ void __init setup_arch(char **cmdline_p)
io_delay_init();
+ if (boot_params.secure_boot &&
+ IS_ENABLED(CONFIG_EFI_SECURE_BOOT_LOCK_DOWN)) {
+ lock_kernel_down();
+ pr_info("Secure boot enabled\n");
+ }
+
/*
* Parse the ACPI tables for possible boot-time SMP configuration.
*/
diff --git a/kernel/module.c b/kernel/module.c
index f57dd63186e6..2a021c340efd 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2744,7 +2744,7 @@ static int module_sig_check(struct load_info *info, int flags)
}
/* Not having a signature is only an error if we're strict. */
- if (err == -ENOKEY && !sig_enforce)
+ if (err == -ENOKEY && !sig_enforce && !kernel_is_locked_down())
err = 0;
return err;
next prev parent reply other threads:[~2016-11-16 21:48 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-16 21:47 [PATCH 00/16] Kernel lockdown David Howells
2016-11-16 21:47 ` [PATCH 01/16] Add the ability to lock down access to the running kernel image David Howells
2016-11-16 22:20 ` Borislav Petkov
2016-11-16 22:40 ` David Howells
2016-12-25 21:20 ` Pavel Machek
2016-12-25 21:44 ` David Howells
2016-11-16 21:47 ` [PATCH 02/16] efi: Get the secure boot status David Howells
2016-11-17 12:37 ` Lukas Wunner
2016-11-22 0:31 ` [PATCH 1/6] x86/efi: Allow invocation of arbitrary runtime services David Howells
2016-11-22 10:20 ` Lukas Wunner
2016-11-22 14:17 ` David Howells
2016-11-22 14:58 ` Joe Perches
2016-11-22 15:52 ` David Howells
2016-11-22 16:25 ` Joe Perches
2016-11-22 16:40 ` David Howells
2016-11-22 16:51 ` Joe Perches
2016-11-22 0:31 ` [PATCH 2/6] arm/efi: " David Howells
2016-11-22 0:31 ` [PATCH 3/6] efi: Add SHIM and image security database GUID definitions David Howells
2016-11-22 0:32 ` [PATCH 4/6] efi: Get the secure boot status David Howells
2016-11-22 10:44 ` Lukas Wunner
2016-11-22 10:49 ` Ard Biesheuvel
2016-11-22 14:47 ` David Howells
2016-11-22 20:30 ` Lukas Wunner
2016-11-23 0:02 ` David Howells
2016-11-22 14:52 ` David Howells
2016-11-22 20:36 ` Lukas Wunner
2016-11-22 14:57 ` David Howells
2016-11-22 0:32 ` [PATCH 5/6] efi: Disable secure boot if shim is in insecure mode David Howells
2016-11-22 13:03 ` Lukas Wunner
2016-11-22 0:32 ` [PATCH 6/6] efi: Add EFI_SECURE_BOOT bit David Howells
2016-11-22 13:04 ` Lukas Wunner
2016-11-21 11:42 ` [PATCH 02/16] efi: Get the secure boot status David Howells
2016-11-21 11:52 ` Ard Biesheuvel
2016-11-21 12:41 ` David Howells
2016-11-21 13:14 ` Ard Biesheuvel
2016-11-21 15:17 ` Lukas Wunner
2016-11-21 15:25 ` Ard Biesheuvel
2016-11-21 11:46 ` David Howells
2016-11-21 19:58 ` Lukas Wunner
2016-11-16 21:47 ` [PATCH 03/16] efi: Disable secure boot if shim is in insecure mode David Howells
2016-11-16 21:47 ` David Howells [this message]
2016-11-16 21:47 ` [PATCH 05/16] efi: Add EFI_SECURE_BOOT bit David Howells
2016-11-17 21:58 ` Ard Biesheuvel
2016-11-18 11:58 ` Josh Boyer
2016-11-18 12:10 ` Ard Biesheuvel
2016-11-18 17:28 ` David Howells
2016-11-16 21:48 ` [PATCH 06/16] Add a sysrq option to exit secure boot mode David Howells
2016-11-16 21:48 ` [PATCH 07/16] kexec: Disable at runtime if the kernel is locked down David Howells
2016-11-16 21:48 ` [PATCH 08/16] Copy secure_boot flag in boot params across kexec reboot David Howells
2016-11-16 21:48 ` [PATCH 09/16] hibernate: Disable when the kernel is locked down David Howells
2016-11-16 21:48 ` [PATCH 10/16] PCI: Lock down BAR access " David Howells
2016-11-16 21:48 ` [PATCH 11/16] x86: Lock down IO port " David Howells
2016-11-16 21:48 ` [PATCH 12/16] ACPI: Limit access to custom_method " David Howells
2016-11-16 21:48 ` [PATCH 13/16] asus-wmi: Restrict debugfs interface " David Howells
2016-11-16 21:48 ` [PATCH 14/16] Restrict /dev/mem and /dev/kmem " David Howells
2016-11-16 21:49 ` [PATCH 15/16] acpi: Ignore acpi_rsdp kernel param when the kernel has been " David Howells
2016-11-16 21:49 ` [PATCH 16/16] x86: Restrict MSR access when the kernel is " David Howells
2016-11-16 22:27 ` [PATCH 00/16] Kernel lockdown One Thousand Gnomes
2016-11-21 19:53 ` Ard Biesheuvel
2016-11-30 14:27 ` One Thousand Gnomes
2016-11-16 22:28 ` Justin Forbes
2016-11-21 23:10 ` [PATCH] Lock down drivers that can have io ports, io mem, irqs and dma changed David Howells
2016-11-22 6:12 ` Dominik Brodowski
2016-11-23 12:58 ` David Howells
2016-11-23 19:21 ` Dominik Brodowski
2016-11-24 17:34 ` David Howells
2016-11-24 20:19 ` Dominik Brodowski
2016-11-25 14:49 ` David Howells
2016-11-28 22:32 ` Corey Minyard
2016-11-29 0:11 ` David Howells
2016-11-29 0:23 ` Corey Minyard
2016-11-29 14:03 ` David Howells
2016-11-29 14:35 ` Corey Minyard
2016-11-30 14:41 ` One Thousand Gnomes
2016-11-30 16:25 ` David Howells
2016-11-29 10:40 ` David Howells
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