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 07/16] kexec: Disable at runtime if the kernel is locked down
Date: Wed, 16 Nov 2016 21:48:07 +0000 [thread overview]
Message-ID: <147933288742.19316.17308231278815492742.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk>
From: Matthew Garrett <matthew.garrett@nebula.com>
kexec permits the loading and execution of arbitrary code in ring 0, which
is something that lock-down is meant to prevent. It makes sense to disable
kexec in this situation.
This does not affect kexec_file_load() which can check for a signature on the
image to be booted.
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
kernel/kexec.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 980936a90ee6..c6aa4620d1bf 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -12,6 +12,7 @@
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/kexec.h>
+#include <linux/security.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/syscalls.h>
@@ -194,6 +195,13 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
return -EPERM;
/*
+ * kexec can be used to circumvent module loading restrictions, so
+ * prevent loading in that case
+ */
+ if (kernel_is_locked_down())
+ return -EPERM;
+
+ /*
* Verify we have a legal set of flags
* This leaves us room for future extensions.
*/
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 ` [PATCH 04/16] efi: Lock down the kernel if booted in secure boot mode David Howells
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 ` David Howells [this message]
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
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=147933288742.19316.17308231278815492742.stgit@warthog.procyon.org.uk \
--to=dhowells@redhat.com \
--cc=keyrings@vger.kernel.org \
--cc=linux-efi@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=matthew.garrett@nebula.com \
/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).