[GIT PULL 0/7] EFI updates for v4.11 part 2

[GIT PULL 0/7] EFI updates for v4.11 part 2

[Ard Biesheuvel]

These are patches that were still being discussed when I sent the first pull
request last week, but we feel they are now in shape to be merged.

Please pull.

The following changes since commit a21a300289bb5a582cc96be23446fa35236a6a9a:

  efi: libstub: Preserve .debug sections after absolute relocation check (2017-01-31 11:47:39 +0000)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git tags/efi-next

for you to fetch changes up to dfe7b0e7e1ab9dc02d754c7dd11e465be0944603:

  efi: libstub: Make file I/O chunking x86-specific (2017-02-03 17:01:06 +0000)

----------------------------------------------------------------
Some more EFI changes we've queued up for v4.11:
* Changes to the EFI init code to infer from various EFI and shim variables
  whether secure boot authentication was performed at boot time. (Note that
  this is the uncontroversial part: I expect some fierce debate about future
  patches that impose or relax certain restrictions based on this information,
  but collecting it is useful in itself.)
* Disable a x86 specific file I/O chunking workaround on ARM so it does not
  spuriously trigger build time checks in the ARM decompressor.

----------------------------------------------------------------
Ard Biesheuvel (1):
      efi: libstub: Make file I/O chunking x86-specific

David Howells (5):
      x86/efi: Allow invocation of arbitrary runtime services
      arm/efi: Allow invocation of arbitrary runtime services
      efi: Add SHIM and image security database GUID definitions
      efi: Get the secure boot status
      efi: Print the secure boot status in x86 setup_arch()

Josh Boyer (1):
      efi: Disable secure boot if shim is in insecure mode

 Documentation/x86/zero-page.txt                |  2 +
 arch/arm/include/asm/efi.h                     |  1 +
 arch/arm64/include/asm/efi.h                   |  1 +
 arch/x86/boot/compressed/eboot.c               |  8 +++
 arch/x86/boot/compressed/head_32.S             |  6 +-
 arch/x86/boot/compressed/head_64.S             |  8 +--
 arch/x86/include/asm/efi.h                     |  5 ++
 arch/x86/include/uapi/asm/bootparam.h          |  3 +-
 arch/x86/kernel/asm-offsets.c                  |  1 +
 arch/x86/kernel/setup.c                        | 14 +++++
 drivers/firmware/efi/libstub/Makefile          |  2 +-
 drivers/firmware/efi/libstub/arm-stub.c        | 63 ++-----------------
 drivers/firmware/efi/libstub/efi-stub-helper.c | 12 +++-
 drivers/firmware/efi/libstub/secureboot.c      | 86 ++++++++++++++++++++++++++
 include/linux/efi.h                            | 11 ++++
 15 files changed, 156 insertions(+), 67 deletions(-)
 create mode 100644 drivers/firmware/efi/libstub/secureboot.c

[PATCH 1/7] x86/efi: Allow invocation of arbitrary runtime services

[Ard Biesheuvel]

From: David Howells <dhowells@redhat.com>

Provide the ability to perform mixed-mode runtime service calls for x86 in
the same way that commit 0a637ee61247bd4bed9b2a07568ef7a1cfc76187
("x86/efi: Allow invocation of arbitrary boot services") provides the
ability to invoke arbitrary boot services.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/boot/compressed/eboot.c   | 1 +
 arch/x86/boot/compressed/head_32.S | 6 +++---
 arch/x86/boot/compressed/head_64.S | 8 ++++----
 arch/x86/include/asm/efi.h         | 5 +++++
 4 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 6d3aeabbce68..f99978db6b6f 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -32,6 +32,7 @@ static void setup_boot_services##bits(struct efi_config *c)		\
 									\
 	table = (typeof(table))sys_table;				\
 									\
+	c->runtime_services = table->runtime;				\
 	c->boot_services = table->boottime;				\
 	c->text_output = table->con_out;				\
 }
diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index fd0b6a272dd5..d85b9625e836 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -82,7 +82,7 @@ ENTRY(efi_pe_entry)
 
 	/* Relocate efi_config->call() */
 	leal	efi32_config(%esi), %eax
-	add	%esi, 32(%eax)
+	add	%esi, 40(%eax)
 	pushl	%eax
 
 	call	make_boot_params
@@ -108,7 +108,7 @@ ENTRY(efi32_stub_entry)
 
 	/* Relocate efi_config->call() */
 	leal	efi32_config(%esi), %eax
-	add	%esi, 32(%eax)
+	add	%esi, 40(%eax)
 	pushl	%eax
 2:
 	call	efi_main
@@ -264,7 +264,7 @@ relocated:
 #ifdef CONFIG_EFI_STUB
 	.data
 efi32_config:
-	.fill 4,8,0
+	.fill 5,8,0
 	.long efi_call_phys
 	.long 0
 	.byte 0
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 4d85e600db78..d2ae1f821e0c 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -264,7 +264,7 @@ ENTRY(efi_pe_entry)
 	/*
 	 * Relocate efi_config->call().
 	 */
-	addq	%rbp, efi64_config+32(%rip)
+	addq	%rbp, efi64_config+40(%rip)
 
 	movq	%rax, %rdi
 	call	make_boot_params
@@ -284,7 +284,7 @@ handover_entry:
 	 * Relocate efi_config->call().
 	 */
 	movq	efi_config(%rip), %rax
-	addq	%rbp, 32(%rax)
+	addq	%rbp, 40(%rax)
 2:
 	movq	efi_config(%rip), %rdi
 	call	efi_main
@@ -456,14 +456,14 @@ efi_config:
 #ifdef CONFIG_EFI_MIXED
 	.global efi32_config
 efi32_config:
-	.fill	4,8,0
+	.fill	5,8,0
 	.quad	efi64_thunk
 	.byte	0
 #endif
 
 	.global efi64_config
 efi64_config:
-	.fill	4,8,0
+	.fill	5,8,0
 	.quad	efi_call
 	.byte	1
 #endif /* CONFIG_EFI_STUB */
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index e99675b9c861..2f77bcefe6b4 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -191,6 +191,7 @@ static inline efi_status_t efi_thunk_set_virtual_address_map(
 struct efi_config {
 	u64 image_handle;
 	u64 table;
+	u64 runtime_services;
 	u64 boot_services;
 	u64 text_output;
 	efi_status_t (*call)(unsigned long, ...);
@@ -226,6 +227,10 @@ static inline bool efi_is_64bit(void)
 #define __efi_call_early(f, ...)					\
 	__efi_early()->call((unsigned long)f, __VA_ARGS__);
 
+#define efi_call_runtime(f, ...)					\
+	__efi_early()->call(efi_table_attr(efi_runtime_services, f,	\
+		__efi_early()->runtime_services), __VA_ARGS__)
+
 extern bool efi_reboot_required(void);
 
 #else
-- 
2.7.4

[PATCH 3/7] efi: Add SHIM and image security database GUID definitions

[Ard Biesheuvel]

From: David Howells <dhowells@redhat.com>

Add the definitions for shim and image security database, both of which
are used widely in various Linux distros.

Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 include/linux/efi.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/efi.h b/include/linux/efi.h
index 8c6e007a5408..52c87de3e50d 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -611,6 +611,9 @@ void efi_native_runtime_setup(void);
 #define EFI_CONSOLE_OUT_DEVICE_GUID		EFI_GUID(0xd3b36f2c, 0xd551, 0x11d4,  0x9a, 0x46, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d)
 #define APPLE_PROPERTIES_PROTOCOL_GUID		EFI_GUID(0x91bd12fe, 0xf6c3, 0x44fb,  0xa5, 0xb7, 0x51, 0x22, 0xab, 0x30, 0x3a, 0xe0)
 
+#define EFI_IMAGE_SECURITY_DATABASE_GUID	EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596,  0xa3, 0xbc, 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f)
+#define EFI_SHIM_LOCK_GUID			EFI_GUID(0x605dab50, 0xe046, 0x4300,  0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23)
+
 /*
  * This GUID is used to pass to the kernel proper the struct screen_info
  * structure that was populated by the stub based on the GOP protocol instance
-- 
2.7.4

Re: [PATCH 3/7] efi: Add SHIM and image security database GUID definitions

[Ingo Molnar]

* Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:

> From: David Howells <dhowells@redhat.com>
> 
> Add the definitions for shim and image security database, both of which
> are used widely in various Linux distros.
> 
> Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
> Signed-off-by: David Howells <dhowells@redhat.com>
> Cc: Matt Fleming <matt@codeblueprint.co.uk>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

That's not a valid SOB chain: the SOB of the author of the patch (David Howells) 
must come first.

I changed it to:

  Signed-off-by: David Howells <dhowells@redhat.com>
  Acked-by: Josh Boyer <jwboyer@fedoraproject.org>
  Cc: Matt Fleming <matt@codeblueprint.co.uk>
  Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Please holler if that's not OK.

Thanks,

	Ingo

Re: [PATCH 3/7] efi: Add SHIM and image security database GUID definitions

[Ard Biesheuvel]

On 7 February 2017 at 07:52, Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
>
> * Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
>
>> From: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>>
>> Add the definitions for shim and image security database, both of which
>> are used widely in various Linux distros.
>>
>> Signed-off-by: Josh Boyer <jwboyer-rxtnV0ftBwyoClj4AeEUq9i2O/JbrIOy@public.gmane.org>
>> Signed-off-by: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>> Cc: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>
> That's not a valid SOB chain: the SOB of the author of the patch (David Howells)
> must come first.
>
> I changed it to:
>
>   Signed-off-by: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>   Acked-by: Josh Boyer <jwboyer-rxtnV0ftBwyoClj4AeEUq9i2O/JbrIOy@public.gmane.org>
>   Cc: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
>   Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>
> Please holler if that's not OK.
>

Ah yes, thanks for spotting that.

OK with me

Re: [PATCH 3/7] efi: Add SHIM and image security database GUID definitions

[David Howells]

Ingo Molnar <mingo@kernel.org> wrote:

> That's not a valid SOB chain: the SOB of the author of the patch (David Howells) 
> must come first.
> 
> I changed it to:
> 
>   Signed-off-by: David Howells <dhowells@redhat.com>
>   Acked-by: Josh Boyer <jwboyer@fedoraproject.org>
>   Cc: Matt Fleming <matt@codeblueprint.co.uk>
>   Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> 
> Please holler if that's not OK.

Actually, it should be authored by Josh Boyer.  Somehow the authorship got
lost.

David

Re: [PATCH 3/7] efi: Add SHIM and image security database GUID definitions

[Ingo Molnar]

* David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:

> Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
> 
> > That's not a valid SOB chain: the SOB of the author of the patch (David Howells) 
> > must come first.
> > 
> > I changed it to:
> > 
> >   Signed-off-by: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> >   Acked-by: Josh Boyer <jwboyer-rxtnV0ftBwyoClj4AeEUq9i2O/JbrIOy@public.gmane.org>
> >   Cc: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
> >   Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> > 
> > Please holler if that's not OK.
> 
> Actually, it should be authored by Josh Boyer.  Somehow the authorship got
> lost.

Ok, I have fixed it accordingly.

Thanks,

	Ingo

[PATCH 2/7] arm/efi: Allow invocation of arbitrary runtime services

[Ard Biesheuvel]

From: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

efi_call_runtime() is provided for x86 to be able abstract mixed mode
support.  Provide this for ARM also so that common code work in mixed mode
also.

Suggested-by: Lukas Wunner <lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
Cc: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
Signed-off-by: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 arch/arm/include/asm/efi.h   | 1 +
 arch/arm64/include/asm/efi.h | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h
index 0b06f5341b45..e4e6a9d6a825 100644
--- a/arch/arm/include/asm/efi.h
+++ b/arch/arm/include/asm/efi.h
@@ -55,6 +55,7 @@ void efi_virtmap_unload(void);
 
 #define efi_call_early(f, ...)		sys_table_arg->boottime->f(__VA_ARGS__)
 #define __efi_call_early(f, ...)	f(__VA_ARGS__)
+#define efi_call_runtime(f, ...)	sys_table_arg->runtime->f(__VA_ARGS__)
 #define efi_is_64bit()			(false)
 
 #define efi_call_proto(protocol, f, instance, ...)			\
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index 0b6b1633017f..e7445281e534 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -50,6 +50,7 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
 
 #define efi_call_early(f, ...)		sys_table_arg->boottime->f(__VA_ARGS__)
 #define __efi_call_early(f, ...)	f(__VA_ARGS__)
+#define efi_call_runtime(f, ...)	sys_table_arg->runtime->f(__VA_ARGS__)
 #define efi_is_64bit()			(true)
 
 #define efi_call_proto(protocol, f, instance, ...)			\
-- 
2.7.4

[PATCH 4/7] efi: Get the secure boot status

[Ard Biesheuvel]

From: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

Get the firmware's secure-boot status in the kernel boot wrapper and stash
it somewhere that the main kernel image can find.

The efi_get_secureboot() function is extracted from the arm stub and (a)
generalised so that it can be called from x86 and (b) made to use
efi_call_runtime() so that it can be run in mixed-mode.

For x86, it is stored in boot_params and can be overridden by the boot
loader or kexec.  This allows secure-boot mode to be passed on to a new
kernel.

Suggested-by: Lukas Wunner <lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
Signed-off-by: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 Documentation/x86/zero-page.txt           |  2 +
 arch/x86/boot/compressed/eboot.c          |  7 ++++
 arch/x86/include/uapi/asm/bootparam.h     |  3 +-
 arch/x86/kernel/asm-offsets.c             |  1 +
 drivers/firmware/efi/libstub/Makefile     |  2 +-
 drivers/firmware/efi/libstub/arm-stub.c   | 63 +++----------------------------
 drivers/firmware/efi/libstub/secureboot.c | 63 +++++++++++++++++++++++++++++++
 include/linux/efi.h                       |  8 ++++
 8 files changed, 90 insertions(+), 59 deletions(-)
 create mode 100644 drivers/firmware/efi/libstub/secureboot.c

diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt
index 95a4d34af3fd..b8527c6b7646 100644
--- a/Documentation/x86/zero-page.txt
+++ b/Documentation/x86/zero-page.txt
@@ -31,6 +31,8 @@ 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/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index f99978db6b6f..801c7a158e55 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -988,6 +988,13 @@ struct boot_params *efi_main(struct efi_config *c,
 	else
 		setup_boot_services32(efi_early);
 
+	/*
+	 * If the boot loader gave us a value for secure_boot then we use that,
+	 * otherwise we ask the BIOS.
+	 */
+	if (boot_params->secure_boot == efi_secureboot_mode_unset)
+		boot_params->secure_boot = efi_get_secureboot(sys_table);
+
 	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 b10bf319ed20..5138dacf8bb8 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -135,7 +135,8 @@ 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/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index c62e015b126c..de827d6ac8c2 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -81,6 +81,7 @@ void common(void) {
 
 	BLANK();
 	OFFSET(BP_scratch, boot_params, scratch);
+	OFFSET(BP_secure_boot, boot_params, secure_boot);
 	OFFSET(BP_loadflags, boot_params, hdr.loadflags);
 	OFFSET(BP_hardware_subarch, boot_params, hdr.hardware_subarch);
 	OFFSET(BP_version, boot_params, hdr.version);
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 33e0e2f1a730..f7425960f6a5 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -28,7 +28,7 @@ OBJECT_FILES_NON_STANDARD	:= y
 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
 KCOV_INSTRUMENT			:= n
 
-lib-y				:= efi-stub-helper.o gop.o
+lib-y				:= efi-stub-helper.o gop.o secureboot.o
 
 # include the stub's generic dependencies from lib/ when building for ARM/arm64
 arm-deps := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c sort.c
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
index 6fca48c9e054..d4056c6be1ec 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -20,52 +20,6 @@
 
 bool __nokaslr;
 
-static int efi_get_secureboot(efi_system_table_t *sys_table_arg)
-{
-	static efi_char16_t const sb_var_name[] = {
-		'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
-	static efi_char16_t const sm_var_name[] = {
-		'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 };
-
-	efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
-	efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
-	u8 val;
-	unsigned long size = sizeof(val);
-	efi_status_t status;
-
-	status = f_getvar((efi_char16_t *)sb_var_name, (efi_guid_t *)&var_guid,
-			  NULL, &size, &val);
-
-	if (status != EFI_SUCCESS)
-		goto out_efi_err;
-
-	if (val == 0)
-		return 0;
-
-	status = f_getvar((efi_char16_t *)sm_var_name, (efi_guid_t *)&var_guid,
-			  NULL, &size, &val);
-
-	if (status != EFI_SUCCESS)
-		goto out_efi_err;
-
-	if (val == 1)
-		return 0;
-
-	return 1;
-
-out_efi_err:
-	switch (status) {
-	case EFI_NOT_FOUND:
-		return 0;
-	case EFI_DEVICE_ERROR:
-		return -EIO;
-	case EFI_SECURITY_VIOLATION:
-		return -EACCES;
-	default:
-		return -EINVAL;
-	}
-}
-
 efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
 			     void *__image, void **__fh)
 {
@@ -157,7 +111,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
 	efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
 	unsigned long reserve_addr = 0;
 	unsigned long reserve_size = 0;
-	int secure_boot = 0;
+	enum efi_secureboot_mode secure_boot;
 	struct screen_info *si;
 
 	/* Check if we were booted by the EFI firmware */
@@ -227,19 +181,14 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
 		pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");
 
 	secure_boot = efi_get_secureboot(sys_table);
-	if (secure_boot > 0)
-		pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
-
-	if (secure_boot < 0) {
-		pr_efi_err(sys_table,
-			"could not determine UEFI Secure Boot status.\n");
-	}
 
 	/*
-	 * Unauthenticated device tree data is a security hazard, so
-	 * ignore 'dtb=' unless UEFI Secure Boot is disabled.
+	 * Unauthenticated device tree data is a security hazard, so ignore
+	 * 'dtb=' unless UEFI Secure Boot is disabled.  We assume that secure
+	 * boot is enabled if we can't determine its state.
 	 */
-	if (secure_boot != 0 && strstr(cmdline_ptr, "dtb=")) {
+	if (secure_boot != efi_secureboot_mode_disabled &&
+	    strstr(cmdline_ptr, "dtb=")) {
 		pr_efi(sys_table, "Ignoring DTB from command line.\n");
 	} else {
 		status = handle_cmdline_files(sys_table, image, cmdline_ptr,
diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c
new file mode 100644
index 000000000000..62d6904da800
--- /dev/null
+++ b/drivers/firmware/efi/libstub/secureboot.c
@@ -0,0 +1,63 @@
+/*
+ * Secure boot handling.
+ *
+ * Copyright (C) 2013,2014 Linaro Limited
+ *     Roy Franz <roy.franz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org
+ * Copyright (C) 2013 Red Hat, Inc.
+ *     Mark Salter <msalter-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
+ *
+ * This file is part of the Linux kernel, and is made available under the
+ * terms of the GNU General Public License version 2.
+ *
+ */
+
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+/* BIOS variables */
+static const efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
+static const efi_char16_t const efi_SecureBoot_name[] = {
+	'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0
+};
+static const efi_char16_t const efi_SetupMode_name[] = {
+	'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0
+};
+
+#define get_efi_var(name, vendor, ...) \
+	efi_call_runtime(get_variable, \
+			 (efi_char16_t *)(name), (efi_guid_t *)(vendor), \
+			 __VA_ARGS__);
+
+/*
+ * Determine whether we're in secure boot mode.
+ */
+enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg)
+{
+	u8 secboot, setupmode;
+	unsigned long size;
+	efi_status_t status;
+
+	size = sizeof(secboot);
+	status = get_efi_var(efi_SecureBoot_name, &efi_variable_guid,
+			     NULL, &size, &secboot);
+	if (status != EFI_SUCCESS)
+		goto out_efi_err;
+
+	size = sizeof(setupmode);
+	status = get_efi_var(efi_SetupMode_name, &efi_variable_guid,
+			     NULL, &size, &setupmode);
+	if (status != EFI_SUCCESS)
+		goto out_efi_err;
+
+	if (secboot == 0 || setupmode == 1)
+		return efi_secureboot_mode_disabled;
+
+	pr_efi(sys_table_arg, "UEFI Secure Boot is enabled.\n");
+	return efi_secureboot_mode_enabled;
+
+out_efi_err:
+	pr_efi_err(sys_table_arg, "Could not determine UEFI Secure Boot status.\n");
+	if (status == EFI_NOT_FOUND)
+		return efi_secureboot_mode_disabled;
+	return efi_secureboot_mode_unknown;
+}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 52c87de3e50d..729ee6a2579b 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1480,6 +1480,14 @@ efi_status_t efi_setup_gop(efi_system_table_t *sys_table_arg,
 bool efi_runtime_disabled(void);
 extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
 
+enum efi_secureboot_mode {
+	efi_secureboot_mode_unset,
+	efi_secureboot_mode_unknown,
+	efi_secureboot_mode_disabled,
+	efi_secureboot_mode_enabled,
+};
+enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table);
+
 /*
  * Arch code can implement the following three template macros, avoiding
  * reptition for the void/non-void return cases of {__,}efi_call_virt():
-- 
2.7.4

[PATCH 7/7] efi: libstub: Make file I/O chunking x86-specific

[Ard Biesheuvel]

The ARM decompressor is finicky when it comes to uninitialized variables
with local linkage, the reason being that it may relocate .text and .bss
independently when executing from ROM. This is only possible if all
references into .bss from .text are absolute, and this happens to be the
case for references emitted under -fpic to symbols with external linkage,
and so all .bss references must involve symbols with external linkage.

When building the ARM stub using clang, the initialized local variable
__chunk_size is optimized into a zero-initialized flag that indicates
whether chunking is in effect or not. This flag is therefore emitted into
.bss, which triggers the ARM decompressor's diagnostics, resulting in a
failed build.

Under UEFI, we never execute the decompressor from ROM, so the diagnostic
makes little sense here. But we can easily work around the issue by making
__chunk_size global instead.

However, given that the file I/O chunking that is controlled by the
__chunk_size variable is intended to work around known bugs on various
x86 implementations of UEFI, we can simply make the chunking an x86
specific feature. This is an improvement by itself, and also removes the
need to parse the efi= options in the stub entirely.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Tested-by: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
Reviewed-by: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
---
 drivers/firmware/efi/libstub/efi-stub-helper.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 6ee9164251a9..2a07b867bec7 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -414,6 +414,14 @@ efi_status_t efi_parse_options(char *cmdline)
 	char *str;
 
 	/*
+	 * Currently, the only efi= option we look for is 'nochunk', which
+	 * is intended to work around known issues on certain x86 UEFI
+	 * versions. So ignore for now on other architectures.
+	 */
+	if (!IS_ENABLED(CONFIG_X86))
+		return EFI_SUCCESS;
+
+	/*
 	 * If no EFI parameters were specified on the cmdline we've got
 	 * nothing to do.
 	 */
@@ -586,7 +594,9 @@ efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 			size = files[j].size;
 			while (size) {
 				unsigned long chunksize;
-				if (size > __chunk_size)
+
+				if (IS_ENABLED(CONFIG_X86) &&
+				    size > __chunk_size)
 					chunksize = __chunk_size;
 				else
 					chunksize = size;
-- 
2.7.4

[PATCH 5/7] efi: Disable secure boot if shim is in insecure mode

[Ard Biesheuvel]

From: Josh Boyer <jwboyer@fedoraproject.org>

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>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/firmware/efi/libstub/secureboot.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c
index 62d6904da800..766ac06dac84 100644
--- a/drivers/firmware/efi/libstub/secureboot.c
+++ b/drivers/firmware/efi/libstub/secureboot.c
@@ -23,6 +23,12 @@ static const efi_char16_t const efi_SetupMode_name[] = {
 	'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0
 };
 
+/* SHIM variables */
+static const efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID;
+static efi_char16_t const shim_MokSBState_name[] = {
+	'M', 'o', 'k', 'S', 'B', 'S', 't', 'a', 't', 'e', 0
+};
+
 #define get_efi_var(name, vendor, ...) \
 	efi_call_runtime(get_variable, \
 			 (efi_char16_t *)(name), (efi_guid_t *)(vendor), \
@@ -33,7 +39,8 @@ static const efi_char16_t const efi_SetupMode_name[] = {
  */
 enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg)
 {
-	u8 secboot, setupmode;
+	u32 attr;
+	u8 secboot, setupmode, moksbstate;
 	unsigned long size;
 	efi_status_t status;
 
@@ -52,6 +59,22 @@ enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg)
 	if (secboot == 0 || setupmode == 1)
 		return efi_secureboot_mode_disabled;
 
+	/*
+	 * See if a user has put shim into insecure mode. If so, and if the
+	 * variable doesn't have the runtime attribute set, we might as well
+	 * honor that.
+	 */
+	size = sizeof(moksbstate);
+	status = get_efi_var(shim_MokSBState_name, &shim_guid,
+			     &attr, &size, &moksbstate);
+
+	/* If it fails, we don't care why.  Default to secure */
+	if (status != EFI_SUCCESS)
+		goto secure_boot_enabled;
+	if (!(attr & EFI_VARIABLE_RUNTIME_ACCESS) && moksbstate == 1)
+		return efi_secureboot_mode_disabled;
+
+secure_boot_enabled:
 	pr_efi(sys_table_arg, "UEFI Secure Boot is enabled.\n");
 	return efi_secureboot_mode_enabled;
 
-- 
2.7.4

[PATCH 6/7] efi: Print the secure boot status in x86 setup_arch()

[Ard Biesheuvel]

From: David Howells <dhowells@redhat.com>

Print the secure boot status in the x86 setup_arch() but otherwise do
nothing more for now. More functionality will be added later, but this at
least allows for testing.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
[ardb: use efi_enabled() instead of IS_ENABLED(CONFIG_EFI)]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/kernel/setup.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 4cfba947d774..69780edf0dde 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1176,6 +1176,20 @@ void __init setup_arch(char **cmdline_p)
 	/* Allocate bigger log buffer */
 	setup_log_buf(1);
 
+	if (efi_enabled(EFI_BOOT)) {
+		switch (boot_params.secure_boot) {
+		case efi_secureboot_mode_disabled:
+			pr_info("Secure boot disabled\n");
+			break;
+		case efi_secureboot_mode_enabled:
+			pr_info("Secure boot enabled\n");
+			break;
+		default:
+			pr_info("Secure boot could not be determined\n");
+			break;
+		}
+	}
+
 	reserve_initrd();
 
 	acpi_table_upgrade();
-- 
2.7.4