Bugzilla: N/A
Upstream-status: Fedora mustard. Replaced by securelevels, but that was nak'd
From 0fc411ee00c81b8a18b1417d31f2736fad155d89 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Fri, 9 Aug 2013 17:58:15 -0400
Subject: [PATCH 01/14] 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 05f2447..de97e77 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -515,6 +515,8 @@ 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. */
@@ -625,6 +627,11 @@ 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 dc58274..81206c1 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3860,3 +3860,13 @@ 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(secure_modules);
--
1.8.3.1
From b94942e55b519e70366e970cea3665c464d1b7da Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Thu, 8 Mar 2012 10:10:38 -0500
Subject: [PATCH 02/14] 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 d8eb880..a851ad6 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 */
@@ -644,6 +645,9 @@ 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) {
@@ -950,6 +954,9 @@ 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;
@@ -1057,6 +1064,9 @@ 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 36f34509fe52cc49e1b1f6815a3f235040f64a03 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Thu, 8 Mar 2012 10:35:59 -0500
Subject: [PATCH 03/14] 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 67d9800dcf60467e076587b0aac67bcdc516cfe2 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Fri, 9 Mar 2012 08:39:37 -0500
Subject: [PATCH 04/14] 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 | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c
index 12b62f2..50647b3 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 (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 bdf3761573167c20c72b151c1088b24fd24869ac Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Fri, 9 Mar 2012 08:46:50 -0500
Subject: [PATCH 05/14] 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 65d88af5a2c6bb6d01da17819d8ba782bd208837 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Fri, 9 Mar 2012 09:28:15 -0500
Subject: [PATCH 06/14] 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 4aa42b7fa5d7f79eb1d179e728ffa561fd9cf354 Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer@redhat.com>
Date: Mon, 25 Jun 2012 19:57:30 -0400
Subject: [PATCH 07/14] 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 e5f416c..9311c00 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>
@@ -249,7 +250,7 @@ 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 c9e62c2ce588d98a774a3853e56d95e48b9df98c Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Fri, 9 Aug 2013 03:33:56 -0400
Subject: [PATCH 08/14] 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 | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 2a74f30..13601e3 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>
@@ -943,6 +944,13 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
return -EPERM;
/*
+ * kexec can be used to circumvent module loading restrictions, so
+ * prevent loading in that case
+ */
+ if (secure_modules())
+ return -EPERM;
+
+ /*
* Verify we have a legal set of flags
* This leaves us room for future extensions.
*/
--
1.8.3.1
From d0e3cb2c13dc9634849ddacf75b6f0d94147516a Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Tue, 3 Sep 2013 11:23:29 -0400
Subject: [PATCH 09/14] uswsusp: Disable when module loading is restricted
uswsusp allows a user process to dump and then restore kernel state, which
makes it possible to avoid module loading restrictions. Prevent this when
any restrictions have been imposed on loading modules.
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
---
kernel/power/user.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 957f061..e570609d 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -24,6 +24,7 @@
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/freezer.h>
+#include <linux/module.h>
#include <asm/uaccess.h>
@@ -49,6 +50,9 @@ static int snapshot_open(struct inode *inode, struct file *filp)
struct snapshot_data *data;
int error;
+ if (secure_modules())
+ return -EPERM;
+
lock_system_sleep();
if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
--
1.8.3.1
From b238417ed3c5a0b21bbfcac84f6c70011b8977c0 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Fri, 8 Feb 2013 11:12:13 -0800
Subject: [PATCH 10/14] 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 05266b5..e2bd647 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(®s, uregs, sizeof regs)) {
err = -EFAULT;
break;
--
1.8.3.1
From c3a9afb3b580b4f721d245fc5d13e378b99b9cd8 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthew.garrett@nebula.com>
Date: Fri, 9 Aug 2013 18:36:30 -0400
Subject: [PATCH 11/14] 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>
---
Documentation/x86/zero-page.txt | 2 ++
arch/x86/Kconfig | 10 ++++++++++
arch/x86/boot/compressed/eboot.c | 36 +++++++++++++++++++++++++++++++++++
arch/x86/include/uapi/asm/bootparam.h | 3 ++-
arch/x86/kernel/setup.c | 6 ++++++
include/linux/module.h | 6 ++++++
kernel/module.c | 7 +++++++
7 files changed, 69 insertions(+), 1 deletion(-)
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 725e157..fe212ef 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1604,6 +1604,16 @@ config EFI_STUB
See Documentation/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 a7677ba..4e172e9 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -12,6 +12,7 @@
#include <asm/efi.h>
#include <asm/setup.h>
#include <asm/desc.h>
+#include <asm/bootparam_utils.h>
#undef memcpy /* Use memcpy from misc.c */
@@ -741,6 +742,37 @@ free_mem_map:
}
+static int get_secure_boot(void)
+{
+ 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;
+}
+
+
/*
* On success we return a pointer to a boot_params structure, and NULL
* on failure.
@@ -760,6 +792,10 @@ struct boot_params *efi_main(void *handle, efi_system_table_t *_table,
if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
goto fail;
+ sanitize_boot_params(boot_params);
+
+ boot_params->secure_boot = get_secure_boot();
+
setup_graphics(boot_params);
setup_efi_pci(boot_params);
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index 9c3733c..a7ba210 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]; /* 0x1ed */
/*
* 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 918d489..fe429c1 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1127,6 +1127,12 @@ 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 de97e77..d69fe19 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -190,6 +190,12 @@ 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 81206c1..e1428f0 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3861,6 +3861,13 @@ 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
From 27a1aa77c7fbaaae8c6a776190a38dcbf3c3d6d2 Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer@redhat.com>
Date: Tue, 5 Feb 2013 19:25:05 -0500
Subject: [PATCH 12/14] efi: Disable secure boot if shim is in insecure mode
A user can manually tell the shim boot loader to disable validation of
images it loads. When a user does this, it creates a UEFI variable called
MokSBState that does not have the runtime attribute set. Given that the
user explicitly disabled validation, we can honor that and not enable
secure boot mode if that variable is set.
Signed-off-by: Josh Boyer <jwboyer@redhat.com>
---
arch/x86/boot/compressed/eboot.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 4e172e9..4905f4d 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -744,8 +744,9 @@ free_mem_map:
static int get_secure_boot(void)
{
- u8 sb, setup;
+ u8 sb, setup, moksbstate;
unsigned long datasize = sizeof(sb);
+ u32 attr;
efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
efi_status_t status;
@@ -769,6 +770,23 @@ static int get_secure_boot(void)
if (setup == 1)
return 0;
+ /* See if a user has put shim into insecure_mode. If so, and the variable
+ * doesn't have the runtime attribute set, we might as well honor that.
+ */
+ var_guid = EFI_SHIM_LOCK_GUID;
+ status = efi_call_phys5(sys_table->runtime->get_variable,
+ L"MokSBState", &var_guid, &attr, &datasize,
+ &moksbstate);
+
+ /* If it fails, we don't care why. Default to secure */
+ if (status != EFI_SUCCESS)
+ return 1;
+
+ if (!(attr & EFI_VARIABLE_RUNTIME_ACCESS)) {
+ if (moksbstate == 1)
+ return 0;
+ }
+
return 1;
}
--
1.8.3.1
From 2a445ca2c187da4497ef5f68f111574fd2b0d419 Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer@fedoraproject.org>
Date: Tue, 27 Aug 2013 13:28:43 -0400
Subject: [PATCH 13/14] efi: Make EFI_SECURE_BOOT_SIG_ENFORCE depend on EFI
The functionality of the config option is dependent upon the platform being
UEFI based. Reflect this in the config deps.
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
---
arch/x86/Kconfig | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fe212ef..bf83fd3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1605,7 +1605,8 @@ config EFI_STUB
See Documentation/efi-stub.txt for more information.
config EFI_SECURE_BOOT_SIG_ENFORCE
- def_bool n
+ def_bool n
+ depends on EFI
prompt "Force module signing when UEFI Secure Boot is enabled"
---help---
UEFI Secure Boot provides a mechanism for ensuring that the
--
1.8.3.1
From b1c533cc1d1ca7a03497cc4f2e1b029bde95633c Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer@fedoraproject.org>
Date: Tue, 27 Aug 2013 13:33:03 -0400
Subject: [PATCH 14/14] efi: Add EFI_SECURE_BOOT bit
UEFI machines can be booted in Secure Boot mode. Add a EFI_SECURE_BOOT bit
for use with efi_enabled.
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
---
arch/x86/kernel/setup.c | 2 ++
include/linux/efi.h | 1 +
2 files changed, 3 insertions(+)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index fe429c1..469fbf0 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1129,7 +1129,9 @@ void __init setup_arch(char **cmdline_p)
#ifdef CONFIG_EFI_SECURE_BOOT_SIG_ENFORCE
if (boot_params.secure_boot) {
+ set_bit(EFI_SECURE_BOOT, &x86_efi_facility);
enforce_signed_modules();
+ pr_info("Secure boot enabled\n");
}
#endif
diff --git a/include/linux/efi.h b/include/linux/efi.h
index bc5687d..b010a2e 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -653,6 +653,7 @@ extern int __init efi_setup_pcdp_console(char *);
#define EFI_RUNTIME_SERVICES 3 /* Can we use runtime services? */
#define EFI_MEMMAP 4 /* Can we use EFI memory map? */
#define EFI_64BIT 5 /* Is the firmware 64-bit? */
+#define EFI_SECURE_BOOT 6 /* Are we in Secure Boot mode? */
#ifdef CONFIG_EFI
# ifdef CONFIG_X86
--
1.8.3.1