From 92cd776b04e2f43476bcc033b8468e3cd682639b Mon Sep 17 00:00:00 2001 From: Matthew Garrett Date: Wed, 5 Apr 2017 17:40:30 +0100 Subject: [PATCH] ACPI: Limit access to custom_method when the kernel is locked down custom_method effectively allows arbitrary access to system memory, making it possible for an attacker to circumvent restrictions on module loading. Disable it if the kernel is locked down. Signed-off-by: Matthew Garrett Signed-off-by: David Howells Gbp-Pq: Topic features/all/lockdown Gbp-Pq: Name 0053-ACPI-Limit-access-to-custom_method-when-the-kernel-i.patch --- drivers/acpi/custom_method.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c index c68e72414a6..e4d721c330c 100644 --- a/drivers/acpi/custom_method.c +++ b/drivers/acpi/custom_method.c @@ -29,6 +29,9 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf, struct acpi_table_header table; acpi_status status; + if (kernel_is_locked_down()) + return -EPERM; + if (!(*ppos)) { /* parse the table header to get the table length */ if (count <= sizeof(struct acpi_table_header)) -- 2.30.2