Bugzilla: N/A
Upstream-status: Fedora mustard. Replaced by securelevels, but that was nak'd
From 3b083aa4b42c6f2e814742b24e1948aced3a5e3f 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 f520a767c86c..fc9b54eb779e 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 81e727cf6df9..fc14f48915dd 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3843,3 +3843,13 @@ 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);
--
1.9.3
From 5c9708ebd7a52bf432745dc9b739c54666f2789d 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 9ff0a901ecf7..8d0d5d92b8d9 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -30,6 +30,7 @@
#include <linux/vgaarb.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
+#include <linux/module.h>
#include "pci.h"
static int sysfs_initialized; /* = 0 */
@@ -704,6 +705,9 @@ static ssize_t 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) {
@@ -998,6 +1002,9 @@ static int 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;
@@ -1099,6 +1106,9 @@ static ssize_t 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 3f155e78513f..4265ea07e3b0 100644
--- a/drivers/pci/proc.c
+++ b/drivers/pci/proc.c
@@ -116,6 +116,9 @@ static ssize_t proc_bus_pci_write(struct file *file, const char __user *buf,
int size = dev->cfg_size;
int cnt;
+ if (secure_modules())
+ return -EPERM;
+
if (pos >= size)
return 0;
if (nbytes >= size)
@@ -195,6 +198,9 @@ 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);
@@ -233,7 +239,7 @@ 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 b91c4da68365..98f5637304d1 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);
--
1.9.3
From c5f35519151d28b1a3c3dee5cb67fd67befa7fb6 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 4ddaf66ea35f..00b440307419 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 917403fe10da..cdf839f9defe 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -27,6 +27,7 @@
#include <linux/export.h>
#include <linux/io.h>
#include <linux/aio.h>
+#include <linux/module.h>
#include <asm/uaccess.h>
@@ -568,6 +569,9 @@ 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) {
--
1.9.3
From 24b607adc80fdebbc3497efc4b997a62edc06280 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 c68e72414a67..4277938af700 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))
--
1.9.3
From 215559c7708671e85ceb42f6e25445b9b27f6c38 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 3c6ccedc82b6..960c46536c65 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -1592,6 +1592,9 @@ 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)
@@ -1608,6 +1611,9 @@ 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);
@@ -1632,6 +1638,9 @@ 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);
--
1.9.3
From b709a5110b728b526063c6814413a8c0f0d01203 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 cdf839f9defe..c63cf93b00eb 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -164,6 +164,9 @@ static ssize_t write_mem(struct file *file, const char __user *buf,
if (p != *ppos)
return -EFBIG;
+ if (secure_modules())
+ return -EPERM;
+
if (!valid_phys_addr_range(p, count))
return -EFAULT;
@@ -502,6 +505,9 @@ 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);
--
1.9.3
From 2896018a1c991e19691ab203a9e9010e898587e7 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 bad25b070fe0..0606585e8b93 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -44,6 +44,7 @@
#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
--
1.9.3
From a9c7c2c5e39d3e687b3e90845a753673144a754b 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 6748688813d0..d4d88984bf45 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -33,6 +33,7 @@
#include <linux/swap.h>
#include <linux/syscore_ops.h>
#include <linux/compiler.h>
+#include <linux/module.h>
#include <asm/page.h>
#include <asm/uaccess.h>
@@ -946,6 +947,13 @@ 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.
*/
--
1.9.3
From 4ce6023b9f02d5397156976568b3aad88b2f5b95 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 09/14] 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 c9603ac80de5..8bef43fc3f40 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;
--
1.9.3
From c95290110f65724e58b7506281759c0bac59b9f5 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 10/14] 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 199f453cb4de..ec38acf00b40 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 a8f749ef0fdc..35bfd8259993 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1556,6 +1556,16 @@ config EFI_MIXED
If unsure, say N.
+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 0331d765c2bb..85defaf5a27c 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 */
@@ -809,6 +810,37 @@ out:
return status;
}
+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_early->call((unsigned long)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_early->call((unsigned long)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;
+}
+
+
/*
* See if we have Graphics Output Protocol
*/
@@ -1372,6 +1404,10 @@ struct boot_params *efi_main(struct efi_config *c,
else
setup_boot_services32(efi_early);
+ 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 225b0988043a..90dbfb73e11f 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -133,7 +133,8 @@ 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 78a0e6298922..8ecfec85e527 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1142,6 +1142,12 @@ 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 fc9b54eb779e..7377bc851461 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -188,6 +188,12 @@ 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 fc14f48915dd..2d68d276f3b6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3844,6 +3844,13 @@ 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
--
1.9.3
From f0baa6f34da3f151c059ca3043945837db0ca8d1 Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer@fedoraproject.org>
Date: Tue, 5 Feb 2013 19:25:05 -0500
Subject: [PATCH 11/14] 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@fedoraproject.org>
---
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 85defaf5a27c..b4013a4ba005 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -812,8 +812,9 @@ out:
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;
@@ -837,6 +838,23 @@ 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_early->call((unsigned long)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;
}
--
1.9.3
From 6bc90bfd4c13fd6cc4a536630807406c16395bf5 Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer@fedoraproject.org>
Date: Tue, 27 Aug 2013 13:28:43 -0400
Subject: [PATCH 12/14] 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 35bfd8259993..746b1b63da8c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1557,7 +1557,8 @@ config EFI_MIXED
If unsure, say N.
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
--
1.9.3
From 292f6faa86f44fe261c8da58cc2c7f65aa0acad6 Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer@fedoraproject.org>
Date: Tue, 27 Aug 2013 13:33:03 -0400
Subject: [PATCH 13/14] 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 8ecfec85e527..5ce785fc9f05 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1144,7 +1144,9 @@ void __init setup_arch(char **cmdline_p)
#ifdef CONFIG_EFI_SECURE_BOOT_SIG_ENFORCE
if (boot_params.secure_boot) {
+ set_bit(EFI_SECURE_BOOT, &efi.flags);
enforce_signed_modules();
+ pr_info("Secure boot enabled\n");
}
#endif
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 41bbf8ba4ba8..e73f391fd3c8 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -917,6 +917,7 @@ extern int __init efi_setup_pcdp_console(char *);
#define EFI_MEMMAP 4 /* Can we use EFI memory map? */
#define EFI_64BIT 5 /* Is the firmware 64-bit? */
#define EFI_ARCH_1 6 /* First arch-specific bit */
+#define EFI_SECURE_BOOT 7 /* Are we in Secure Boot mode? */
#ifdef CONFIG_EFI
/*
--
1.9.3
From 594e605ee9589150919aa113e3e01163168ad041 Mon Sep 17 00:00:00 2001
From: Josh Boyer <jwboyer@fedoraproject.org>
Date: Fri, 20 Jun 2014 08:53:24 -0400
Subject: [PATCH 14/14] hibernate: Disable in a signed modules environment
There is currently no way to verify the resume image when returning
from hibernate. This might compromise the signed modules trust model,
so until we can work with signed hibernate images we disable it in
a secure modules environment.
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
---
kernel/power/hibernate.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index fcc2611d3f14..61711801a9c4 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -28,6 +28,7 @@
#include <linux/syscore_ops.h>
#include <linux/ctype.h>
#include <linux/genhd.h>
+#include <linux/module.h>
#include <trace/events/power.h>
#include "power.h"
@@ -65,7 +66,7 @@ static const struct platform_hibernation_ops *hibernation_ops;
bool hibernation_available(void)
{
- return (nohibernate == 0);
+ return ((nohibernate == 0) && !secure_modules());
}
/**
--
1.9.3