From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Howells Subject: [PATCH 19/24] x86/mmiotrace: Lock down the testmmiotrace module Date: Wed, 11 Apr 2018 17:26:42 +0100 Message-ID: <152346400272.4030.10900275407737137506.stgit@warthog.procyon.org.uk> References: <152346387861.4030.4408662483445703127.stgit@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <152346387861.4030.4408662483445703127.stgit@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org To: torvalds@linux-foundation.org Cc: linux-man@vger.kernel.org, linux-api@vger.kernel.org, jmorris@namei.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-security-module@vger.kernel.org List-Id: linux-man@vger.kernel.org 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 Signed-off-by: David Howells cc: Steven Rostedt cc: Ingo Molnar cc: "H. Peter Anvin" 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");