[PATCH 14/27] ACPI: Limit access to custom_method when the kernel is locked down
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From: jlee@suse.com (joeyli)
Date: 2017-10-20 06:45:17
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On Thu, Oct 19, 2017 at 03:52:19PM +0100, David Howells wrote:
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>
I have reviewed this patch. Please feel free to add: Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com> Thanks! Joey Lee
quoted hunk ↗ jump to hunk
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-efi" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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