[21/27] x86/mmiotrace: Lock down the testmmiotrace module

Message ID	20190228231203.212359-21-matthewgarrett@google.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-security-module-owner@kernel.org> Date: Thu, 28 Feb 2019 15:11:57 -0800 In-Reply-To: <20190228231203.212359-1-matthewgarrett@google.com> Message-Id: <20190228231203.212359-21-matthewgarrett@google.com> Mime-Version: 1.0 References: <CACdnJuvW47m3JvEcuEX1bsr+L2Ht9LDn_iCuPbHLOoaohOFW4Q@mail.gmail.com> <20190228231203.212359-1-matthewgarrett@google.com> Subject: [PATCH 21/27] x86/mmiotrace: Lock down the testmmiotrace module From: Matthew Garrett <matthewgarrett@google.com> To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk
Series	[PULL,REQUEST] Lock down patches \| expand [PULL,REQUEST] Lock down patches [02/27] Add a SysRq option to lift kernel lockdown [03/27] Enforce module signatures if the kernel is locked down [04/27] Restrict /dev/{mem,kmem,port} when the kernel is locked down [05/27] kexec_load: Disable at runtime if the kernel is locked down [06/27] Copy secure_boot flag in boot params across kexec reboot [07/27] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE [08/27] kexec_file: Restrict at runtime if the kernel is locked down [09/27] hibernate: Disable when the kernel is locked down [10/27] uswsusp: Disable when the kernel is locked down [11/27] PCI: Lock down BAR access when the kernel is locked down [12/27] x86: Lock down IO port access when the kernel is locked down [13/27] x86/msr: Restrict MSR access when the kernel is locked down [14/27] ACPI: Limit access to custom_method when the kernel is locked down [15/27] acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down [16/27] acpi: Disable ACPI table override if the kernel is locked down [17/27] acpi: Disable APEI error injection if the kernel is locked down [18/27] Prohibit PCMCIA CIS storage when the kernel is locked down [19/27] Lock down TIOCSSERIAL [20/27] Lock down module params that specify hardware parameters (eg. ioport) [21/27] x86/mmiotrace: Lock down the testmmiotrace module [22/27] Lock down /proc/kcore [23/27] Lock down kprobes [24/27] bpf: Restrict kernel image access functions when the kernel is locked down [25/27] Lock down perf [26/27] debugfs: Restrict debugfs when the kernel is locked down [27/27] lockdown: Print current->comm in restriction messages

Message ID

20190228231203.212359-21-matthewgarrett@google.com (mailing list archive)

State

New, archived

Headers

Date: Thu, 28 Feb 2019 15:11:57 -0800
In-Reply-To: <20190228231203.212359-1-matthewgarrett@google.com>
Message-Id: <20190228231203.212359-21-matthewgarrett@google.com>
Mime-Version: 1.0
References: 
 <CACdnJuvW47m3JvEcuEX1bsr+L2Ht9LDn_iCuPbHLOoaohOFW4Q@mail.gmail.com>
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Subject: [PATCH 21/27] x86/mmiotrace: Lock down the testmmiotrace module
From: Matthew Garrett <matthewgarrett@google.com>
To: jmorris@namei.org
Cc: linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, dhowells@redhat.com
Content-Type: text/plain; charset="UTF-8"
Sender: owner-linux-security-module@vger.kernel.org
Precedence: bulk

Series

[PULL,REQUEST] Lock down patches | expand

Commit Message

Matthew Garrett Feb. 28, 2019, 11:11 p.m. UTC

From: David Howells <dhowells@redhat.com>

The testmmiotrace module shouldn't be permitted when the kernel is locked
down as it can be used to arbitrarily read and write MMIO space.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Howells <dhowells@redhat.com
cc: Thomas Gleixner <tglx@linutronix.de>
cc: Steven Rostedt <rostedt@goodmis.org>
cc: Ingo Molnar <mingo@kernel.org>
cc: "H. Peter Anvin" <hpa@zytor.com>
cc: x86@kernel.org
---
 arch/x86/mm/testmmiotrace.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/mm/testmmiotrace.c b/arch/x86/mm/testmmiotrace.c
index f6ae6830b341..bbaad357f5d7 100644
--- a/arch/x86/mm/testmmiotrace.c
+++ b/arch/x86/mm/testmmiotrace.c
@@ -115,6 +115,9 @@  static int __init init(void)
 {
 	unsigned long size = (read_far) ? (8 << 20) : (16 << 10);
 
+	if (kernel_is_locked_down("MMIO trace testing"))
+		return -EPERM;
+
 	if (mmio_address == 0) {
 		pr_err("you have to use the module argument mmio_address.\n");
 		pr_err("DO NOT LOAD THIS MODULE UNLESS YOU REALLY KNOW WHAT YOU ARE DOING!\n");

[21/27] x86/mmiotrace: Lock down the testmmiotrace module

Commit Message

Patch