From 17832506ee9b52bc8e00c2ec89b49257998171ed Mon Sep 17 00:00:00 2001

From: Matthew Garrett <matthew.garrett@nebula.com>

Date: Mon, 19 Aug 2013 13:26:02 -0400

Subject: [PATCH 01/13] Add secure_modules() call

Provide a single call to allow kernel code to determine whether the system

has been configured to either disable module loading entirely or to load

only modules signed with a trusted key.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

---

 include/linux/module.h |  7 +++++++

 kernel/module.c        | 10 ++++++++++

 2 files changed, 17 insertions(+)

diff --git a/include/linux/module.h b/include/linux/module.h

index 46f1ea0..0c266b2 100644

--- a/include/linux/module.h

+++ b/include/linux/module.h

@@ -509,6 +509,8 @@ int unregister_module_notifier(struct notifier_block * nb);

 extern void print_modules(void);

+extern bool secure_modules(void);

+

 #else /* !CONFIG_MODULES... */

 /* Given an address, look for it in the exception tables. */

@@ -619,6 +621,11 @@ static inline int unregister_module_notifier(struct notifier_block * nb)

 static inline void print_modules(void)

 {

 }

+

+static inline bool secure_modules(void)

+{

+	return false;

+}

 #endif /* CONFIG_MODULES */

 #ifdef CONFIG_SYSFS

diff --git a/kernel/module.c b/kernel/module.c

index 2069158..499ee57 100644

--- a/kernel/module.c

+++ b/kernel/module.c

@@ -3852,3 +3852,13 @@ void module_layout(struct module *mod,

 }

 EXPORT_SYMBOL(module_layout);

 #endif

+

+bool secure_modules(void)

+{

+#ifdef CONFIG_MODULE_SIG

+	return (sig_enforce || modules_disabled);

+#else

+	return modules_disabled;

+#endif

+}

+EXPORT_SYMBOL_GPL(secure_modules);

-- 

1.8.3.1

From e347503648ace6a4b71dfb566365f1aa19657746 Mon Sep 17 00:00:00 2001

From: Matthew Garrett <matthew.garrett@nebula.com>

Date: Mon, 19 Aug 2013 13:26:03 -0400

Subject: [PATCH 02/13] PCI: Lock down BAR access when module security is

 enabled

Any hardware that can potentially generate DMA has to be locked down from

userspace in order to avoid it being possible for an attacker to modify

kernel code, allowing them to circumvent disabled module loading or module

signing. Default to paranoid - in future we can potentially relax this for

sufficiently IOMMU-isolated devices.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

---

 drivers/pci/pci-sysfs.c | 10 ++++++++++

 drivers/pci/proc.c      |  8 +++++++-

 drivers/pci/syscall.c   |  3 ++-

 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c

index c0dbe1f..cd4e35f 100644

--- a/drivers/pci/pci-sysfs.c

+++ b/drivers/pci/pci-sysfs.c

@@ -29,6 +29,7 @@

 #include <linux/slab.h>

 #include <linux/vgaarb.h>

 #include <linux/pm_runtime.h>

+#include <linux/module.h>

 #include "pci.h"

 static int sysfs_initialized;	/* = 0 */

@@ -624,6 +625,9 @@ pci_write_config(struct file* filp, struct kobject *kobj,

 	loff_t init_off = off;

 	u8 *data = (u8*) buf;

+	if (secure_modules())

+		return -EPERM;

+

 	if (off > dev->cfg_size)

 		return 0;

 	if (off + count > dev->cfg_size) {

@@ -930,6 +934,9 @@ pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr,

 	resource_size_t start, end;

 	int i;

+	if (secure_modules())

+		return -EPERM;

+

 	for (i = 0; i < PCI_ROM_RESOURCE; i++)

 		if (res == &pdev->resource[i])

 			break;

@@ -1037,6 +1044,9 @@ pci_write_resource_io(struct file *filp, struct kobject *kobj,

 		      struct bin_attribute *attr, char *buf,

 		      loff_t off, size_t count)

 {

+	if (secure_modules())

+		return -EPERM;

+

 	return pci_resource_io(filp, kobj, attr, buf, off, count, true);

 }

diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c

index cdc7836..e3d498b 100644

--- a/drivers/pci/proc.c

+++ b/drivers/pci/proc.c

@@ -117,6 +117,9 @@ proc_bus_pci_write(struct file *file, const char __user *buf, size_t nbytes, lof

 	int size = dev->cfg_size;

 	int cnt;

+	if (secure_modules())

+		return -EPERM;

+

 	if (pos >= size)

 		return 0;

 	if (nbytes >= size)

@@ -196,6 +199,9 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd,

 #endif /* HAVE_PCI_MMAP */

 	int ret = 0;

+	if (secure_modules())

+		return -EPERM;

+

 	switch (cmd) {

 	case PCIIOC_CONTROLLER:

 		ret = pci_domain_nr(dev->bus);

@@ -234,7 +240,7 @@ static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct *vma)

 	struct pci_filp_private *fpriv = file->private_data;

 	int i, ret;

-	if (!capable(CAP_SYS_RAWIO))

+	if (!capable(CAP_SYS_RAWIO) || secure_modules())

 		return -EPERM;

 	/* Make sure the caller is mapping a real resource for this device */

diff --git a/drivers/pci/syscall.c b/drivers/pci/syscall.c

index e1c1ec5..bffbf71 100644

--- a/drivers/pci/syscall.c

+++ b/drivers/pci/syscall.c

@@ -10,6 +10,7 @@

 #include <linux/errno.h>

 #include <linux/pci.h>

 #include <linux/syscalls.h>

+#include <linux/module.h>

 #include <asm/uaccess.h>

 #include "pci.h"

@@ -92,7 +93,7 @@ SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn,

 	u32 dword;

 	int err = 0;

-	if (!capable(CAP_SYS_ADMIN))

+	if (!capable(CAP_SYS_ADMIN) || secure_modules())

 		return -EPERM;

 	dev = pci_get_bus_and_slot(bus, dfn);

-- 

1.8.3.1

From b846e3958d3f4ff875ec958efba8b681ccbae04e Mon Sep 17 00:00:00 2001

From: Matthew Garrett <matthew.garrett@nebula.com>

Date: Mon, 19 Aug 2013 13:26:04 -0400

Subject: [PATCH 03/13] x86: Lock down IO port access when module security is

 enabled

IO port access would permit users to gain access to PCI configuration

registers, which in turn (on a lot of hardware) give access to MMIO register

space. This would potentially permit root to trigger arbitrary DMA, so lock

it down by default.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

---

 arch/x86/kernel/ioport.c | 5 +++--

 drivers/char/mem.c       | 4 ++++

 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c

index 4ddaf66..00b4403 100644

--- a/arch/x86/kernel/ioport.c

+++ b/arch/x86/kernel/ioport.c

@@ -15,6 +15,7 @@

 #include <linux/thread_info.h>

 #include <linux/syscalls.h>

 #include <linux/bitmap.h>

+#include <linux/module.h>

 #include <asm/syscalls.h>

 /*

@@ -28,7 +29,7 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)

 	if ((from + num <= from) || (from + num > IO_BITMAP_BITS))

 		return -EINVAL;

-	if (turn_on && !capable(CAP_SYS_RAWIO))

+	if (turn_on && (!capable(CAP_SYS_RAWIO) || secure_modules()))

 		return -EPERM;

 	/*

@@ -103,7 +104,7 @@ SYSCALL_DEFINE1(iopl, unsigned int, level)

 		return -EINVAL;

 	/* Trying to gain more privileges? */

 	if (level > old) {

-		if (!capable(CAP_SYS_RAWIO))

+		if (!capable(CAP_SYS_RAWIO) || secure_modules())

 			return -EPERM;

 	}

 	regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | (level << 12);

diff --git a/drivers/char/mem.c b/drivers/char/mem.c

index f895a8c..1af8664 100644

--- a/drivers/char/mem.c

+++ b/drivers/char/mem.c

@@ -28,6 +28,7 @@

 #include <linux/export.h>

 #include <linux/io.h>

 #include <linux/aio.h>

+#include <linux/module.h>

 #include <asm/uaccess.h>

@@ -563,6 +564,9 @@ static ssize_t write_port(struct file *file, const char __user *buf,

 	unsigned long i = *ppos;

 	const char __user *tmp = buf;

+	if (secure_modules())

+		return -EPERM;

+

 	if (!access_ok(VERIFY_READ, buf, count))

 		return -EFAULT;

 	while (count-- > 0 && i < 65536) {

-- 

1.8.3.1

From 8c11e2cc989eece2d4978cfbc83f9b898f3cd1aa Mon Sep 17 00:00:00 2001

From: Matthew Garrett <matthew.garrett@nebula.com>

Date: Mon, 19 Aug 2013 13:26:05 -0400

Subject: [PATCH 04/13] ACPI: Limit access to custom_method

custom_method effectively allows arbitrary access to system memory, making

it possible for an attacker to circumvent restrictions on module loading.

Disable it if any such restrictions have been enabled.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

---

 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 12b62f2..55a013f 100644

--- a/drivers/acpi/custom_method.c

+++ b/drivers/acpi/custom_method.c

@@ -7,6 +7,7 @@

 #include <linux/kernel.h>

 #include <linux/uaccess.h>

 #include <linux/debugfs.h>

+#include <linux/module.h>

 #include <acpi/acpi_drivers.h>

 #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 (secure_modules())

+		return -EPERM;

+

 	if (!(*ppos)) {

 		/* parse the table header to get the table length */

 		if (count <= sizeof(struct acpi_table_header))

-- 

1.8.3.1

From 968ccfb32df5d5c9673c57641ebf90b25c0df880 Mon Sep 17 00:00:00 2001

From: Matthew Garrett <matthew.garrett@nebula.com>

Date: Mon, 19 Aug 2013 13:26:06 -0400

Subject: [PATCH 05/13] asus-wmi: Restrict debugfs interface when module

 loading is restricted

We have no way of validating what all of the Asus WMI methods do on a

given machine, and there's a risk that some will allow hardware state to

be manipulated in such a way that arbitrary code can be executed in the

kernel, circumventing module loading restrictions. Prevent that if any of

these features are enabled.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

---

 drivers/platform/x86/asus-wmi.c | 9 +++++++++

 1 file changed, 9 insertions(+)

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c

index 19c313b..db18ef66 100644

--- a/drivers/platform/x86/asus-wmi.c

+++ b/drivers/platform/x86/asus-wmi.c

@@ -1618,6 +1618,9 @@ static int show_dsts(struct seq_file *m, void *data)

 	int err;

 	u32 retval = -1;

+	if (secure_modules())

+		return -EPERM;

+

 	err = asus_wmi_get_devstate(asus, asus->debug.dev_id, &retval);

 	if (err < 0)

@@ -1634,6 +1637,9 @@ static int show_devs(struct seq_file *m, void *data)

 	int err;

 	u32 retval = -1;

+	if (secure_modules())

+		return -EPERM;

+

 	err = asus_wmi_set_devstate(asus->debug.dev_id, asus->debug.ctrl_param,

 				    &retval);

@@ -1658,6 +1664,9 @@ static int show_call(struct seq_file *m, void *data)

 	union acpi_object *obj;

 	acpi_status status;

+	if (secure_modules())

+		return -EPERM;

+

 	status = wmi_evaluate_method(ASUS_WMI_MGMT_GUID,

 				     1, asus->debug.method_id,

 				     &input, &output);

-- 

1.8.3.1

From e492d0a80bb591c34391757f97fc5aa8eb198e4f Mon Sep 17 00:00:00 2001

From: Matthew Garrett <matthew.garrett@nebula.com>

Date: Mon, 19 Aug 2013 13:26:07 -0400

Subject: [PATCH 06/13] Restrict /dev/mem and /dev/kmem when module loading is

 restricted

Allowing users to write to address space makes it possible for the kernel

to be subverted, avoiding module loading restrictions. Prevent this when

any restrictions have been imposed on loading modules.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

---

 drivers/char/mem.c | 6 ++++++

 1 file changed, 6 insertions(+)

diff --git a/drivers/char/mem.c b/drivers/char/mem.c

index 1af8664..61406c8 100644

--- a/drivers/char/mem.c

+++ b/drivers/char/mem.c

@@ -159,6 +159,9 @@ static ssize_t write_mem(struct file *file, const char __user *buf,

 	unsigned long copied;

 	void *ptr;

+	if (secure_modules())

+		return -EPERM;

+

 	if (!valid_phys_addr_range(p, count))

 		return -EFAULT;

@@ -497,6 +500,9 @@ static ssize_t write_kmem(struct file *file, const char __user *buf,

 	char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */

 	int err = 0;

+	if (secure_modules())

+		return -EPERM;

+

 	if (p < (unsigned long) high_memory) {

 		unsigned long to_write = min_t(unsigned long, count,

 					       (unsigned long)high_memory - p);

-- 

1.8.3.1

From 145913d656bfe8216032b38a576ac150699521e5 Mon Sep 17 00:00:00 2001

From: Josh Boyer <jwboyer@redhat.com>

Date: Mon, 19 Aug 2013 13:26:08 -0400

Subject: [PATCH 07/13] acpi: Ignore acpi_rsdp kernel parameter when module

 loading is restricted

This option allows userspace to pass the RSDP address to the kernel, which

makes it possible for a user to circumvent any restrictions imposed on

loading modules. Disable it in that case.

Signed-off-by: Josh Boyer <jwboyer@redhat.com>

---

 drivers/acpi/osl.c | 3 ++-

 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c

index 6ab2c35..e4c4410 100644

--- a/drivers/acpi/osl.c

+++ b/drivers/acpi/osl.c

@@ -45,6 +45,7 @@

 #include <linux/list.h>

 #include <linux/jiffies.h>

 #include <linux/semaphore.h>

+#include <linux/module.h>

 #include <asm/io.h>

 #include <asm/uaccess.h>

@@ -245,7 +246,7 @@ early_param("acpi_rsdp", setup_acpi_rsdp);

 acpi_physical_address __init acpi_os_get_root_pointer(void)

 {

 #ifdef CONFIG_KEXEC

-	if (acpi_rsdp)

+	if (acpi_rsdp && !secure_modules())

 		return acpi_rsdp;

 #endif

-- 

1.8.3.1

From 012ac79f54ab746114d8276d8858a3df18b10e22 Mon Sep 17 00:00:00 2001

From: Matthew Garrett <matthew.garrett@nebula.com>

Date: Mon, 19 Aug 2013 13:26:10 -0400

Subject: [PATCH 08/13] x86: Restrict MSR access when module loading is

 restricted

Writing to MSRs should not be allowed if module loading is restricted,

since it could lead to execution of arbitrary code in kernel mode. Based

on a patch by Kees Cook.

Cc: Kees Cook <keescook@chromium.org>

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

---

 arch/x86/kernel/msr.c | 7 +++++++

 1 file changed, 7 insertions(+)

diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c

index 88458fa..d08f7e3 100644

--- a/arch/x86/kernel/msr.c

+++ b/arch/x86/kernel/msr.c

@@ -103,6 +103,9 @@ static ssize_t msr_write(struct file *file, const char __user *buf,

 	int err = 0;

 	ssize_t bytes = 0;

+	if (secure_modules())

+		return -EPERM;

+

 	if (count % 8)

 		return -EINVAL;	/* Invalid chunk size */

@@ -150,6 +153,10 @@ static long msr_ioctl(struct file *file, unsigned int ioc, unsigned long arg)

 			err = -EBADF;

 			break;

 		}

+		if (secure_modules()) {

+			err = -EPERM;

+			break;

+		}

 		if (copy_from_user(&regs, uregs, sizeof regs)) {

 			err = -EFAULT;

 			break;

-- 

1.8.3.1

From a44d2968968fd667c8cbeba7c043f674d17e7ce7 Mon Sep 17 00:00:00 2001

From: Matthew Garrett <matthew.garrett@nebula.com>

Date: Mon, 19 Aug 2013 13:26:09 -0400

Subject: [PATCH 09/13] kexec: Disable at runtime if the kernel enforces module

 loading restrictions

kexec permits the loading and execution of arbitrary code in ring 0, which

is something that module signing enforcement is meant to prevent. It makes

sense to disable kexec in this situation.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

---

 kernel/kexec.c | 4 ++++

 1 file changed, 4 insertions(+)

diff --git a/kernel/kexec.c b/kernel/kexec.c

index 59f7b55..1a7690f 100644

--- a/kernel/kexec.c

+++ b/kernel/kexec.c

@@ -32,6 +32,7 @@

 #include <linux/vmalloc.h>

 #include <linux/swap.h>

 #include <linux/syscore_ops.h>

+#include <linux/module.h>

 #include <asm/page.h>

 #include <asm/uaccess.h>

@@ -1645,6 +1646,9 @@ int kernel_kexec(void)

 		goto Unlock;

 	}

+	if (secure_modules())

+		return -EPERM;

+

 #ifdef CONFIG_KEXEC_JUMP

 	if (kexec_image->preserve_context) {

 		lock_system_sleep();

-- 

1.8.3.1

From f8f879da5dcc060a990a3b660aa5f340429cc4ed Mon Sep 17 00:00:00 2001

From: Matthew Garrett <matthew.garrett@nebula.com>

Date: Mon, 19 Aug 2013 13:26:11 -0400

Subject: [PATCH 10/13] Add option to automatically enforce module signatures

 when in Secure Boot mode

UEFI Secure Boot provides a mechanism for ensuring that the firmware will

only load signed bootloaders and kernels. Certain use cases may also

require that all kernel modules also be signed. Add a configuration option

that enforces this automatically when enabled.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>

---

 Documentation/x86/zero-page.txt        |  2 ++

 arch/x86/Kconfig                       | 10 ++++++++++

 arch/x86/boot/compressed/eboot.c       | 33 +++++++++++++++++++++++++++++++++

 arch/x86/include/asm/bootparam_utils.h |  8 ++++++--

 arch/x86/include/uapi/asm/bootparam.h  |  3 ++-

 arch/x86/kernel/setup.c                |  6 ++++++

 include/linux/module.h                 |  6 ++++++

 kernel/module.c                        |  7 +++++++

 8 files changed, 72 insertions(+), 3 deletions(-)

diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt

index 199f453..ec38acf 100644

--- a/Documentation/x86/zero-page.txt

+++ b/Documentation/x86/zero-page.txt

@@ -30,6 +30,8 @@ Offset	Proto	Name		Meaning

 1E9/001	ALL	eddbuf_entries	Number of entries in eddbuf (below)

 1EA/001	ALL	edd_mbr_sig_buf_entries	Number of entries in edd_mbr_sig_buffer

 				(below)

+1EB/001	ALL     kbd_status      Numlock is enabled

+1EC/001	ALL     secure_boot	Secure boot is enabled in the firmware

 1EF/001	ALL	sentinel	Used to detect broken bootloaders

 290/040	ALL	edd_mbr_sig_buffer EDD MBR signatures

 2D0/A00	ALL	e820_map	E820 memory map table

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig

index b32ebf9..6a6c19b 100644

--- a/arch/x86/Kconfig

+++ b/arch/x86/Kconfig

@@ -1581,6 +1581,16 @@ config EFI_STUB

 	  See Documentation/x86/efi-stub.txt for more information.

+config EFI_SECURE_BOOT_SIG_ENFORCE

+        def_bool n

+	prompt "Force module signing when UEFI Secure Boot is enabled"

+	---help---

+	  UEFI Secure Boot provides a mechanism for ensuring that the

+	  firmware will only load signed bootloaders and kernels. Certain

+	  use cases may also require that all kernel modules also be signed.

+	  Say Y here to automatically enable module signature enforcement

+	  when a system boots with UEFI Secure Boot enabled.

+

 config SECCOMP

 	def_bool y

 	prompt "Enable seccomp to safely compute untrusted bytecode"

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c

index b7388a4..145294d 100644

--- a/arch/x86/boot/compressed/eboot.c

+++ b/arch/x86/boot/compressed/eboot.c

@@ -861,6 +861,37 @@ fail:

 	return status;

 }

+static int get_secure_boot(efi_system_table_t *_table)

+{

+	u8 sb, setup;

+	unsigned long datasize = sizeof(sb);

+	efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;

+	efi_status_t status;

+

+	status = efi_call_phys5(sys_table->runtime->get_variable,

+				L"SecureBoot", &var_guid, NULL, &datasize, &sb);

+

+	if (status != EFI_SUCCESS)

+		return 0;

+

+	if (sb == 0)

+		return 0;

+

+

+	status = efi_call_phys5(sys_table->runtime->get_variable,

+				L"SetupMode", &var_guid, NULL, &datasize,

+				&setup);

+

+	if (status != EFI_SUCCESS)

+		return 0;

+

+	if (setup == 1)

+		return 0;

+

+	return 1;

+}

+

+

 /*

  * Because the x86 boot code expects to be passed a boot_params we

  * need to create one ourselves (usually the bootloader would create

@@ -1169,6 +1200,8 @@ struct boot_params *efi_main(void *handle, efi_system_table_t *_table,

 	if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)

 		goto fail;

+	boot_params->secure_boot = get_secure_boot(sys_table);

+

 	setup_graphics(boot_params);

 	setup_efi_pci(boot_params);

diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h

index 4a8cb8d..25f9cf1 100644

--- a/arch/x86/include/asm/bootparam_utils.h

+++ b/arch/x86/include/asm/bootparam_utils.h

@@ -38,9 +38,13 @@ static void sanitize_boot_params(struct boot_params *boot_params)

 		memset(&boot_params->ext_ramdisk_image, 0,

 		       (char *)&boot_params->efi_info -

 			(char *)&boot_params->ext_ramdisk_image);

-		memset(&boot_params->kbd_status, 0,

+		memset(&boot_params->kbd_status, 0, sizeof(boot_params->kbd_status));

+		/* don't clear boot_params->secure_boot.  we set that ourselves

+		 * earlier.

+		 */

+		memset(&boot_params->_pad5[0], 0,

 		       (char *)&boot_params->hdr -

-		       (char *)&boot_params->kbd_status);

+		       (char *)&boot_params->_pad5[0]);

 		memset(&boot_params->_pad7[0], 0,

 		       (char *)&boot_params->edd_mbr_sig_buffer[0] -

 			(char *)&boot_params->_pad7[0]);

diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h

index c15ddaf..d35da96 100644

--- a/arch/x86/include/uapi/asm/bootparam.h

+++ b/arch/x86/include/uapi/asm/bootparam.h

@@ -131,7 +131,8 @@ struct boot_params {

 	__u8  eddbuf_entries;				/* 0x1e9 */

 	__u8  edd_mbr_sig_buf_entries;			/* 0x1ea */

 	__u8  kbd_status;				/* 0x1eb */

-	__u8  _pad5[3];					/* 0x1ec */

+	__u8  secure_boot;				/* 0x1ec */

+	__u8  _pad5[2];					/* 0x1ec */

 	/*

 	 * The sentinel is set to a nonzero value (0xff) in header.S.

 	 *

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c

index f8ec578..deeb7bc 100644

--- a/arch/x86/kernel/setup.c

+++ b/arch/x86/kernel/setup.c

@@ -1129,6 +1129,12 @@ void __init setup_arch(char **cmdline_p)

 	io_delay_init();

+#ifdef CONFIG_EFI_SECURE_BOOT_SIG_ENFORCE

+	if (boot_params.secure_boot) {

+		enforce_signed_modules();

+	}

+#endif

+

 	/*

 	 * Parse the ACPI tables for possible boot-time SMP configuration.

 	 */

diff --git a/include/linux/module.h b/include/linux/module.h

index 0c266b2..5a6374a 100644

--- a/include/linux/module.h

+++ b/include/linux/module.h

@@ -184,6 +184,12 @@ const struct exception_table_entry *search_exception_tables(unsigned long add);

 struct notifier_block;

+#ifdef CONFIG_MODULE_SIG

+extern void enforce_signed_modules(void);

+#else

+static inline void enforce_signed_modules(void) {};

+#endif

+

 #ifdef CONFIG_MODULES

 extern int modules_disabled; /* for sysctl */

diff --git a/kernel/module.c b/kernel/module.c

index 499ee57..bc7c987 100644

--- a/kernel/module.c

+++ b/kernel/module.c

@@ -3853,6 +3853,13 @@ void module_layout(struct module *mod,

 EXPORT_SYMBOL(module_layout);

 #endif

+#ifdef CONFIG_MODULE_SIG

+void enforce_signed_modules(void)

+{

+	sig_enforce = true;

+}

+#endif

+

 bool secure_modules(void)

 {

 #ifdef CONFIG_MODULE_SIG

-- 

1.8.3.1