From: Matthew Garrett Date: Wed, 8 Nov 2017 15:11:34 +0000 Subject: [14/29] asus-wmi: Restrict debugfs interface when the kernel is locked down Origin: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit?id=2e6d31b3176ee27d216bb92a3b108f6b19d4719a 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 Reviewed-by: "Lee, Chun-Yi" cc: acpi4asus-user@lists.sourceforge.net cc: platform-driver-x86@vger.kernel.org --- drivers/platform/x86/asus-wmi.c | 9 +++++++++ 1 file changed, 9 insertions(+) Index: linux/drivers/platform/x86/asus-wmi.c =================================================================== --- linux.orig/drivers/platform/x86/asus-wmi.c +++ linux/drivers/platform/x86/asus-wmi.c @@ -2002,6 +2002,9 @@ static int show_dsts(struct seq_file *m, int err; u32 retval = -1; + if (kernel_is_locked_down("Asus WMI")) + return -EPERM; + err = asus_wmi_get_devstate(asus, asus->debug.dev_id, &retval); if (err < 0) @@ -2018,6 +2021,9 @@ static int show_devs(struct seq_file *m, int err; u32 retval = -1; + if (kernel_is_locked_down("Asus WMI")) + return -EPERM; + err = asus_wmi_set_devstate(asus->debug.dev_id, asus->debug.ctrl_param, &retval); @@ -2042,6 +2048,9 @@ static int show_call(struct seq_file *m, union acpi_object *obj; acpi_status status; + if (kernel_is_locked_down("Asus WMI")) + return -EPERM; + status = wmi_evaluate_method(ASUS_WMI_MGMT_GUID, 0, asus->debug.method_id, &input, &output);