Thread (146 messages) 146 messages, 15 authors, 2017-12-07

Lifecycle

  1. Posted David Howells <dhowells@redhat.com>

[PATCH 14/27] ACPI: Limit access to custom_method when the kernel is locked down

From: dhowells@redhat.com (David Howells)
Date: 2017-10-19 14:52:24
Also in: linux-efi, lkml
Subsystem: acpi, the rest · Maintainers: "Rafael J. Wysocki", Linus Torvalds

From: Matthew Garrett <redacted>

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 <redacted>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-acpi at vger.kernel.org
---

 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 c68e72414a67..b33fba70ec51 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("ACPI custom methods"))
+		return -EPERM;
+
 	if (!(*ppos)) {
 		/* parse the table header to get the table length */
 		if (count <= sizeof(struct acpi_table_header))

--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info@ http://vger.kernel.org/majordomo-info.html
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help