OpenE2K
/
linux
6
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

ACPI: configfs: Disallow loading ACPI tables when locked down 

commit 75b0cea7bf upstream.

Like other vectors already patched, this one here allows the root
user to load ACPI tables, which enables arbitrary physical address
writes, which in turn makes it possible to disable lockdown.

Prevents this by checking the lockdown status before allowing a new
ACPI table to be installed. The link in the trailer shows a PoC of
how this might be used.

Link: https://git.zx2c4.com/american-unsigned-language/tree/american-unsigned-language-2.sh
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jason A. Donenfeld 2020-06-15 04:43:32 -06:00 committed by Sasha Levin
parent 3c4f9a5541
commit 824d0b6225
1 changed files with 5 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/acpi/acpi_configfs.c
View File

@ -11,6 +11,7 @@
#include <linux/module.h>
#include <linux/configfs.h>
#include <linux/acpi.h>
#include <linux/security.h>
#include "acpica/accommon.h"
#include "acpica/actables.h"
@ -28,7 +29,10 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
{
const struct acpi_table_header *header = data;
struct acpi_table *table;
int ret;
int ret = security_locked_down(LOCKDOWN_ACPI_TABLES);
if (ret)
return ret;
table = container_of(cfg, struct acpi_table, cfg);