From mboxrd@z Thu Jan 1 00:00:00 1970 From: jlee@suse.com (joeyli) Date: Fri, 20 Oct 2017 14:45:02 +0800 Subject: [PATCH 14/27] ACPI: Limit access to custom_method when the kernel is locked down In-Reply-To: <150842473899.7923.6590815561953001126.stgit@warthog.procyon.org.uk> References: <150842463163.7923.11081723749106843698.stgit@warthog.procyon.org.uk> <150842473899.7923.6590815561953001126.stgit@warthog.procyon.org.uk> Message-ID: <20171020064502.GV3285@linux-l9pv.suse> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org On Thu, Oct 19, 2017 at 03:52:19PM +0100, David Howells wrote: > From: Matthew Garrett > > 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 I have reviewed this patch. Please feel free to add: Reviewed-by: "Lee, Chun-Yi" Thanks! Joey Lee > 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 -- 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 at http://vger.kernel.org/majordomo-info.html