From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Howells Subject: [PATCH 13/16] asus-wmi: Restrict debugfs interface when the kernel is locked down Date: Wed, 16 Nov 2016 21:48:50 +0000 Message-ID: <147933293066.19316.11104613433360959201.stgit@warthog.procyon.org.uk> References: <147933283664.19316.12454053022687659937.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: <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-efi@vger.kernel.org From: Matthew Garrett We have no way of validating what all of the Asus WMI methods do on a given machine - and there's a risk that some will allow hardware state to be manipulated in such a way that arbitrary code can be executed in the kernel, circumventing module loading restrictions. Prevent that if the kernel is locked down. Signed-off-by: Matthew Garrett Signed-off-by: David Howells --- drivers/platform/x86/asus-wmi.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c index ce6ca31a2d09..d860017f5240 100644 --- a/drivers/platform/x86/asus-wmi.c +++ b/drivers/platform/x86/asus-wmi.c @@ -1872,6 +1872,9 @@ static int show_dsts(struct seq_file *m, void *data) int err; u32 retval = -1; + if (kernel_is_locked_down()) + return -EPERM; + err = asus_wmi_get_devstate(asus, asus->debug.dev_id, &retval); if (err < 0) @@ -1888,6 +1891,9 @@ static int show_devs(struct seq_file *m, void *data) int err; u32 retval = -1; + if (kernel_is_locked_down()) + return -EPERM; + err = asus_wmi_set_devstate(asus->debug.dev_id, asus->debug.ctrl_param, &retval); @@ -1912,6 +1918,9 @@ static int show_call(struct seq_file *m, void *data) union acpi_object *obj; acpi_status status; + if (kernel_is_locked_down()) + return -EPERM; + status = wmi_evaluate_method(ASUS_WMI_MGMT_GUID, 1, asus->debug.method_id, &input, &output);