From 3c7af10dc5281fbef68a2febb4af5e7ff88fd816 Mon Sep 17 00:00:00 2001 From: Matthew Garrett Date: Mon, 9 Sep 2013 15:49:40 -0700 Subject: [PATCH] acpi: Limit access to custom_method if securelevel is set Orabug: 21539498 custom_method effectively allows arbitrary access to system memory, making it possible for an attacker to modify the kernel at runtime. Prevent this if securelevel has been set. Signed-off-by: Matthew Garrett Signed-off-by: Santosh Shilimkar --- drivers/acpi/custom_method.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c index c68e72414a67a..359f45d54543a 100644 --- a/drivers/acpi/custom_method.c +++ b/drivers/acpi/custom_method.c @@ -8,6 +8,7 @@ #include #include #include +#include #include "internal.h" @@ -29,6 +30,9 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf, struct acpi_table_header table; acpi_status status; + if (get_securelevel() > 0) + return -EPERM; + if (!(*ppos)) { /* parse the table header to get the table length */ if (count <= sizeof(struct acpi_table_header)) -- 2.50.1