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[GIT PULL 0/5] more EFI changes for v4.14

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  [GIT PULL 0/5] more EFI changes for v4.14 Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-08-25 18:00 +0200
    [PATCH 1/5] efi/libstub: Enable reset attack mitigation Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-08-25 18:00 +0200
      [tip:efi/core] efi/libstub: Enable reset attack mitigation tip-bot for Matthew Garrett <tipbot@zytor.com> - 2017-08-26 10:10 +0200
    [PATCH 2/5] efi/random: Increase size of firmware supplied randomness Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-08-25 18:10 +0200
      [tip:efi/core] efi/random: Increase size of firmware supplied  randomness tip-bot for Ard Biesheuvel <tipbot@zytor.com> - 2017-08-26 10:10 +0200
    [PATCH 4/5] efi: move efi_mem_type() to common code Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-08-25 18:10 +0200
      [tip:efi/core] efi: Move efi_mem_type() to common code tip-bot for Jan Beulich <tipbot@zytor.com> - 2017-08-26 10:10 +0200

#1720217 — [GIT PULL 0/5] more EFI changes for v4.14

The following changes since commit f1a5b53570001b1bcbf890ac6c4be1db99f8cc28:

  firmware/efi/esrt: Constify attribute_group structures (2017-08-21 09:43:51 +0200)

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 c4d2793e5a07d5e63d91715a4393fe47c8345112:

  efi: bgrt: use efi_mem_type() (2017-08-25 10:35:23 +0100)

----------------------------------------------------------------
More EFI changes for v4.14:
- add support for requesting the firmware to wipe RAM at warm reboot
- increase the size of the random seed obtained from UEFI so crng
  fast init can complete earlier
- add 'static' to local function pointer
- move efi_mem_type() to common code and replace an open coded instance
  with it in the BGRT driver

----------------------------------------------------------------
Ard Biesheuvel (1):
      efi/random: Increase size of firmware supplied randomness

Colin Ian King (1):
      efi/reboot: Make function pointer orig_pm_power_off static

Jan Beulich (2):
      efi: move efi_mem_type() to common code
      efi: bgrt: use efi_mem_type()

Matthew Garrett (1):
      efi/libstub: Enable reset attack mitigation

 arch/x86/boot/compressed/eboot.c        |  3 ++
 arch/x86/platform/efi/efi.c             | 19 -----------
 drivers/firmware/efi/Kconfig            | 10 ++++++
 drivers/firmware/efi/efi-bgrt.c         | 22 +------------
 drivers/firmware/efi/efi.c              | 40 +++++++++++++++++++----
 drivers/firmware/efi/libstub/Makefile   |  1 +
 drivers/firmware/efi/libstub/arm-stub.c |  3 ++
 drivers/firmware/efi/libstub/random.c   | 10 +++---
 drivers/firmware/efi/libstub/tpm.c      | 58 +++++++++++++++++++++++++++++++++
 drivers/firmware/efi/reboot.c           |  2 +-
 include/linux/efi.h                     |  9 +++++
 11 files changed, 123 insertions(+), 54 deletions(-)
 create mode 100644 drivers/firmware/efi/libstub/tpm.c

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#1720219 — [PATCH 1/5] efi/libstub: Enable reset attack mitigation

From: Matthew Garrett <mjg59@google.com>

If a machine is reset while secrets are present in RAM, it may be
possible for code executed after the reboot to extract those secrets
from untouched memory. The Trusted Computing Group specified a mechanism
for requesting that the firmware clear all RAM on reset before booting
another OS. This is done by setting the MemoryOverwriteRequestControl
variable at startup. If userspace can ensure that all secrets are
removed as part of a controlled shutdown, it can reset this variable to
0 before triggering a hardware reboot.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/boot/compressed/eboot.c        |  3 ++
 drivers/firmware/efi/Kconfig            | 10 ++++++
 drivers/firmware/efi/libstub/Makefile   |  1 +
 drivers/firmware/efi/libstub/arm-stub.c |  3 ++
 drivers/firmware/efi/libstub/tpm.c      | 58 +++++++++++++++++++++++++++++++++
 include/linux/efi.h                     |  7 ++++
 6 files changed, 82 insertions(+)
 create mode 100644 drivers/firmware/efi/libstub/tpm.c

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index c3e869eaef0c..a1686f3dc295 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -997,6 +997,9 @@ struct boot_params *efi_main(struct efi_config *c,
 	if (boot_params->secure_boot == efi_secureboot_mode_unset)
 		boot_params->secure_boot = efi_get_secureboot(sys_table);
 
+	/* Ask the firmware to clear memory on unclean shutdown */
+	efi_enable_reset_attack_mitigation(sys_table);
+
 	setup_graphics(boot_params);
 
 	setup_efi_pci(boot_params);
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 394db40ed374..2b4c39fdfa91 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -151,6 +151,16 @@ config APPLE_PROPERTIES
 
 	  If unsure, say Y if you have a Mac.  Otherwise N.
 
+config RESET_ATTACK_MITIGATION
+	bool "Reset memory attack mitigation"
+	depends on EFI_STUB
+	help
+	  Request that the firmware clear the contents of RAM after a reboot
+	  using the TCG Platform Reset Attack Mitigation specification. This
+	  protects against an attacker forcibly rebooting the system while it
+	  still contains secrets in RAM, booting another OS and extracting the
+	  secrets.
+
 endmenu
 
 config UEFI_CPER
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index cf81e6cf5ae8..dedf9bde44db 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -30,6 +30,7 @@ OBJECT_FILES_NON_STANDARD	:= y
 KCOV_INSTRUMENT			:= n
 
 lib-y				:= efi-stub-helper.o gop.o secureboot.o
+lib-$(CONFIG_RESET_ATTACK_MITIGATION) += tpm.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 8181ac179d14..1cb2d1c070c3 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -192,6 +192,9 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
 		goto fail_free_cmdline;
 	}
 
+	/* Ask the firmware to clear memory on unclean shutdown */
+	efi_enable_reset_attack_mitigation(sys_table);
+
 	secure_boot = efi_get_secureboot(sys_table);
 
 	/*
diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c
new file mode 100644
index 000000000000..6224cdbc9669
--- /dev/null
+++ b/drivers/firmware/efi/libstub/tpm.c
@@ -0,0 +1,58 @@
+/*
+ * TPM handling.
+ *
+ * Copyright (C) 2016 CoreOS, Inc
+ * Copyright (C) 2017 Google, Inc.
+ *     Matthew Garrett <mjg59@google.com>
+ *
+ * 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>
+
+#include "efistub.h"
+
+static const efi_char16_t efi_MemoryOverWriteRequest_name[] = {
+	'M', 'e', 'm', 'o', 'r', 'y', 'O', 'v', 'e', 'r', 'w', 'r', 'i', 't',
+	'e', 'R', 'e', 'q', 'u', 'e', 's', 't', 'C', 'o', 'n', 't', 'r', 'o',
+	'l', 0
+};
+
+#define MEMORY_ONLY_RESET_CONTROL_GUID \
+	EFI_GUID(0xe20939be, 0x32d4, 0x41be, 0xa1, 0x50, 0x89, 0x7f, 0x85, 0xd4, 0x98, 0x29)
+
+#define get_efi_var(name, vendor, ...) \
+	efi_call_runtime(get_variable, \
+			 (efi_char16_t *)(name), (efi_guid_t *)(vendor), \
+			 __VA_ARGS__)
+
+#define set_efi_var(name, vendor, ...) \
+	efi_call_runtime(set_variable, \
+			 (efi_char16_t *)(name), (efi_guid_t *)(vendor), \
+			 __VA_ARGS__)
+
+/*
+ * Enable reboot attack mitigation. This requests that the firmware clear the
+ * RAM on next reboot before proceeding with boot, ensuring that any secrets
+ * are cleared. If userland has ensured that all secrets have been removed
+ * from RAM before reboot it can simply reset this variable.
+ */
+void efi_enable_reset_attack_mitigation(efi_system_table_t *sys_table_arg)
+{
+	u8 val = 1;
+	efi_guid_t var_guid = MEMORY_ONLY_RESET_CONTROL_GUID;
+	efi_status_t status;
+	unsigned long datasize = 0;
+
+	status = get_efi_var(efi_MemoryOverWriteRequest_name, &var_guid,
+			     NULL, &datasize, NULL);
+
+	if (status == EFI_NOT_FOUND)
+		return;
+
+	set_efi_var(efi_MemoryOverWriteRequest_name, &var_guid,
+		    EFI_VARIABLE_NON_VOLATILE |
+		    EFI_VARIABLE_BOOTSERVICE_ACCESS |
+		    EFI_VARIABLE_RUNTIME_ACCESS, sizeof(val), &val);
+}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 8269bcb8ccf7..12e05118657c 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1497,6 +1497,13 @@ enum efi_secureboot_mode {
 };
 enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table);
 
+#ifdef CONFIG_RESET_ATTACK_MITIGATION
+void efi_enable_reset_attack_mitigation(efi_system_table_t *sys_table_arg);
+#else
+static inline void
+efi_enable_reset_attack_mitigation(efi_system_table_t *sys_table_arg) { }
+#endif
+
 /*
  * Arch code can implement the following three template macros, avoiding
  * reptition for the void/non-void return cases of {__,}efi_call_virt():
-- 
2.11.0

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#1720578 — [tip:efi/core] efi/libstub: Enable reset attack mitigation

Commit-ID:  ccc829ba3624beb9a703fc995d016b836d9eead8
Gitweb:     http://git.kernel.org/tip/ccc829ba3624beb9a703fc995d016b836d9eead8
Author:     Matthew Garrett <mjg59@google.com>
AuthorDate: Fri, 25 Aug 2017 16:50:15 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Sat, 26 Aug 2017 09:20:33 +0200

efi/libstub: Enable reset attack mitigation

If a machine is reset while secrets are present in RAM, it may be
possible for code executed after the reboot to extract those secrets
from untouched memory. The Trusted Computing Group specified a mechanism
for requesting that the firmware clear all RAM on reset before booting
another OS. This is done by setting the MemoryOverwriteRequestControl
variable at startup. If userspace can ensure that all secrets are
removed as part of a controlled shutdown, it can reset this variable to
0 before triggering a hardware reboot.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170825155019.6740-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/boot/compressed/eboot.c        |  3 ++
 drivers/firmware/efi/Kconfig            | 10 ++++++
 drivers/firmware/efi/libstub/Makefile   |  1 +
 drivers/firmware/efi/libstub/arm-stub.c |  3 ++
 drivers/firmware/efi/libstub/tpm.c      | 58 +++++++++++++++++++++++++++++++++
 include/linux/efi.h                     |  7 ++++
 6 files changed, 82 insertions(+)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index c3e869e..a1686f3 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -997,6 +997,9 @@ struct boot_params *efi_main(struct efi_config *c,
 	if (boot_params->secure_boot == efi_secureboot_mode_unset)
 		boot_params->secure_boot = efi_get_secureboot(sys_table);
 
+	/* Ask the firmware to clear memory on unclean shutdown */
+	efi_enable_reset_attack_mitigation(sys_table);
+
 	setup_graphics(boot_params);
 
 	setup_efi_pci(boot_params);
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 394db40..2b4c39f 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -151,6 +151,16 @@ config APPLE_PROPERTIES
 
 	  If unsure, say Y if you have a Mac.  Otherwise N.
 
+config RESET_ATTACK_MITIGATION
+	bool "Reset memory attack mitigation"
+	depends on EFI_STUB
+	help
+	  Request that the firmware clear the contents of RAM after a reboot
+	  using the TCG Platform Reset Attack Mitigation specification. This
+	  protects against an attacker forcibly rebooting the system while it
+	  still contains secrets in RAM, booting another OS and extracting the
+	  secrets.
+
 endmenu
 
 config UEFI_CPER
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index cf81e6c..dedf9bd 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -30,6 +30,7 @@ OBJECT_FILES_NON_STANDARD	:= y
 KCOV_INSTRUMENT			:= n
 
 lib-y				:= efi-stub-helper.o gop.o secureboot.o
+lib-$(CONFIG_RESET_ATTACK_MITIGATION) += tpm.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 8181ac1..1cb2d1c 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -192,6 +192,9 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
 		goto fail_free_cmdline;
 	}
 
+	/* Ask the firmware to clear memory on unclean shutdown */
+	efi_enable_reset_attack_mitigation(sys_table);
+
 	secure_boot = efi_get_secureboot(sys_table);
 
 	/*
diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c
new file mode 100644
index 0000000..6224cdb
--- /dev/null
+++ b/drivers/firmware/efi/libstub/tpm.c
@@ -0,0 +1,58 @@
+/*
+ * TPM handling.
+ *
+ * Copyright (C) 2016 CoreOS, Inc
+ * Copyright (C) 2017 Google, Inc.
+ *     Matthew Garrett <mjg59@google.com>
+ *
+ * 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>
+
+#include "efistub.h"
+
+static const efi_char16_t efi_MemoryOverWriteRequest_name[] = {
+	'M', 'e', 'm', 'o', 'r', 'y', 'O', 'v', 'e', 'r', 'w', 'r', 'i', 't',
+	'e', 'R', 'e', 'q', 'u', 'e', 's', 't', 'C', 'o', 'n', 't', 'r', 'o',
+	'l', 0
+};
+
+#define MEMORY_ONLY_RESET_CONTROL_GUID \
+	EFI_GUID(0xe20939be, 0x32d4, 0x41be, 0xa1, 0x50, 0x89, 0x7f, 0x85, 0xd4, 0x98, 0x29)
+
+#define get_efi_var(name, vendor, ...) \
+	efi_call_runtime(get_variable, \
+			 (efi_char16_t *)(name), (efi_guid_t *)(vendor), \
+			 __VA_ARGS__)
+
+#define set_efi_var(name, vendor, ...) \
+	efi_call_runtime(set_variable, \
+			 (efi_char16_t *)(name), (efi_guid_t *)(vendor), \
+			 __VA_ARGS__)
+
+/*
+ * Enable reboot attack mitigation. This requests that the firmware clear the
+ * RAM on next reboot before proceeding with boot, ensuring that any secrets
+ * are cleared. If userland has ensured that all secrets have been removed
+ * from RAM before reboot it can simply reset this variable.
+ */
+void efi_enable_reset_attack_mitigation(efi_system_table_t *sys_table_arg)
+{
+	u8 val = 1;
+	efi_guid_t var_guid = MEMORY_ONLY_RESET_CONTROL_GUID;
+	efi_status_t status;
+	unsigned long datasize = 0;
+
+	status = get_efi_var(efi_MemoryOverWriteRequest_name, &var_guid,
+			     NULL, &datasize, NULL);
+
+	if (status == EFI_NOT_FOUND)
+		return;
+
+	set_efi_var(efi_MemoryOverWriteRequest_name, &var_guid,
+		    EFI_VARIABLE_NON_VOLATILE |
+		    EFI_VARIABLE_BOOTSERVICE_ACCESS |
+		    EFI_VARIABLE_RUNTIME_ACCESS, sizeof(val), &val);
+}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 4e47f78..c241acc 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1504,6 +1504,13 @@ enum efi_secureboot_mode {
 };
 enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table);
 
+#ifdef CONFIG_RESET_ATTACK_MITIGATION
+void efi_enable_reset_attack_mitigation(efi_system_table_t *sys_table_arg);
+#else
+static inline void
+efi_enable_reset_attack_mitigation(efi_system_table_t *sys_table_arg) { }
+#endif
+
 /*
  * Arch code can implement the following three template macros, avoiding
  * reptition for the void/non-void return cases of {__,}efi_call_virt():

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#1720224 — [PATCH 2/5] efi/random: Increase size of firmware supplied randomness

The crng code requires at least 64 bytes (2 * CHACHA20_BLOCK_SIZE)
to complete the fast boot-time init, so provide that many bytes
when invoking UEFI protocols to seed the entropy pool. Also, add
a notice so we can tell from the boot log when the seeding actually
took place.

Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/firmware/efi/efi.c            |  3 ++-
 drivers/firmware/efi/libstub/random.c | 10 ++++------
 include/linux/efi.h                   |  2 ++
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 6519be44387c..9e822906adcb 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -522,6 +522,7 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz,
 			if (seed != NULL) {
 				add_device_randomness(seed->bits, seed->size);
 				early_memunmap(seed, sizeof(*seed) + size);
+				pr_notice("seeding entropy pool\n");
 			} else {
 				pr_err("Could not map UEFI random seed!\n");
 			}
@@ -867,7 +868,7 @@ static int update_efi_random_seed(struct notifier_block *nb,
 
 	seed = memremap(efi.rng_seed, sizeof(*seed), MEMREMAP_WB);
 	if (seed != NULL) {
-		size = min(seed->size, 32U);
+		size = min(seed->size, EFI_RANDOM_SEED_SIZE);
 		memunmap(seed);
 	} else {
 		pr_err("Could not map UEFI random seed!\n");
diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c
index 7e72954d5860..e0e603a89aa9 100644
--- a/drivers/firmware/efi/libstub/random.c
+++ b/drivers/firmware/efi/libstub/random.c
@@ -145,8 +145,6 @@ efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg,
 	return status;
 }
 
-#define RANDOM_SEED_SIZE	32
-
 efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg)
 {
 	efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;
@@ -162,25 +160,25 @@ efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg)
 		return status;
 
 	status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
-				sizeof(*seed) + RANDOM_SEED_SIZE,
+				sizeof(*seed) + EFI_RANDOM_SEED_SIZE,
 				(void **)&seed);
 	if (status != EFI_SUCCESS)
 		return status;
 
-	status = rng->get_rng(rng, &rng_algo_raw, RANDOM_SEED_SIZE,
+	status = rng->get_rng(rng, &rng_algo_raw, EFI_RANDOM_SEED_SIZE,
 			      seed->bits);
 	if (status == EFI_UNSUPPORTED)
 		/*
 		 * Use whatever algorithm we have available if the raw algorithm
 		 * is not implemented.
 		 */
-		status = rng->get_rng(rng, NULL, RANDOM_SEED_SIZE,
+		status = rng->get_rng(rng, NULL, EFI_RANDOM_SEED_SIZE,
 				      seed->bits);
 
 	if (status != EFI_SUCCESS)
 		goto err_freepool;
 
-	seed->size = RANDOM_SEED_SIZE;
+	seed->size = EFI_RANDOM_SEED_SIZE;
 	status = efi_call_early(install_configuration_table, &rng_table_guid,
 				seed);
 	if (status != EFI_SUCCESS)
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 12e05118657c..8dc3d94a3e3c 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1564,6 +1564,8 @@ efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table,
 				    void *priv,
 				    efi_exit_boot_map_processing priv_func);
 
+#define EFI_RANDOM_SEED_SIZE		64U
+
 struct linux_efi_random_seed {
 	u32	size;
 	u8	bits[];
-- 
2.11.0

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#1720579 — [tip:efi/core] efi/random: Increase size of firmware supplied randomness

Commit-ID:  c2ceb5fd4e921506e86208b82fca716a2c3aad59
Gitweb:     http://git.kernel.org/tip/c2ceb5fd4e921506e86208b82fca716a2c3aad59
Author:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
AuthorDate: Fri, 25 Aug 2017 16:50:16 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Sat, 26 Aug 2017 09:20:33 +0200

efi/random: Increase size of firmware supplied randomness

The crng code requires at least 64 bytes (2 * CHACHA20_BLOCK_SIZE)
to complete the fast boot-time init, so provide that many bytes
when invoking UEFI protocols to seed the entropy pool. Also, add
a notice so we can tell from the boot log when the seeding actually
took place.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170825155019.6740-3-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 drivers/firmware/efi/efi.c            |  3 ++-
 drivers/firmware/efi/libstub/random.c | 10 ++++------
 include/linux/efi.h                   |  2 ++
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index a32e146..c8a27a2 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -541,6 +541,7 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz,
 			if (seed != NULL) {
 				add_device_randomness(seed->bits, seed->size);
 				early_memunmap(seed, sizeof(*seed) + size);
+				pr_notice("seeding entropy pool\n");
 			} else {
 				pr_err("Could not map UEFI random seed!\n");
 			}
@@ -900,7 +901,7 @@ static int update_efi_random_seed(struct notifier_block *nb,
 
 	seed = memremap(efi.rng_seed, sizeof(*seed), MEMREMAP_WB);
 	if (seed != NULL) {
-		size = min(seed->size, 32U);
+		size = min(seed->size, EFI_RANDOM_SEED_SIZE);
 		memunmap(seed);
 	} else {
 		pr_err("Could not map UEFI random seed!\n");
diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c
index 7e72954..e0e603a 100644
--- a/drivers/firmware/efi/libstub/random.c
+++ b/drivers/firmware/efi/libstub/random.c
@@ -145,8 +145,6 @@ efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg,
 	return status;
 }
 
-#define RANDOM_SEED_SIZE	32
-
 efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg)
 {
 	efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;
@@ -162,25 +160,25 @@ efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg)
 		return status;
 
 	status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
-				sizeof(*seed) + RANDOM_SEED_SIZE,
+				sizeof(*seed) + EFI_RANDOM_SEED_SIZE,
 				(void **)&seed);
 	if (status != EFI_SUCCESS)
 		return status;
 
-	status = rng->get_rng(rng, &rng_algo_raw, RANDOM_SEED_SIZE,
+	status = rng->get_rng(rng, &rng_algo_raw, EFI_RANDOM_SEED_SIZE,
 			      seed->bits);
 	if (status == EFI_UNSUPPORTED)
 		/*
 		 * Use whatever algorithm we have available if the raw algorithm
 		 * is not implemented.
 		 */
-		status = rng->get_rng(rng, NULL, RANDOM_SEED_SIZE,
+		status = rng->get_rng(rng, NULL, EFI_RANDOM_SEED_SIZE,
 				      seed->bits);
 
 	if (status != EFI_SUCCESS)
 		goto err_freepool;
 
-	seed->size = RANDOM_SEED_SIZE;
+	seed->size = EFI_RANDOM_SEED_SIZE;
 	status = efi_call_early(install_configuration_table, &rng_table_guid,
 				seed);
 	if (status != EFI_SUCCESS)
diff --git a/include/linux/efi.h b/include/linux/efi.h
index c241acc..33d41df 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1571,6 +1571,8 @@ efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table,
 				    void *priv,
 				    efi_exit_boot_map_processing priv_func);
 
+#define EFI_RANDOM_SEED_SIZE		64U
+
 struct linux_efi_random_seed {
 	u32	size;
 	u8	bits[];

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#1720226 — [PATCH 4/5] efi: move efi_mem_type() to common code

From: Jan Beulich <JBeulich@suse.com>

This follows efi_mem_attributes(), as it's similarly generic. Drop
__weak from that one though (and don't introduce it for efi_mem_type()
in the first place) to make clear that other overrides to these
functions are really not intended.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/platform/efi/efi.c | 19 -------------------
 drivers/firmware/efi/efi.c  | 37 +++++++++++++++++++++++++++++++------
 2 files changed, 31 insertions(+), 25 deletions(-)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index f084d8718ac4..928b6dceeca0 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -1032,25 +1032,6 @@ void __init efi_enter_virtual_mode(void)
 	efi_dump_pagetable();
 }
 
-/*
- * Convenience functions to obtain memory types and attributes
- */
-u32 efi_mem_type(unsigned long phys_addr)
-{
-	efi_memory_desc_t *md;
-
-	if (!efi_enabled(EFI_MEMMAP))
-		return 0;
-
-	for_each_efi_memory_desc(md) {
-		if ((md->phys_addr <= phys_addr) &&
-		    (phys_addr < (md->phys_addr +
-				  (md->num_pages << EFI_PAGE_SHIFT))))
-			return md->type;
-	}
-	return 0;
-}
-
 static int __init arch_parse_efi_cmdline(char *str)
 {
 	if (!str) {
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 9e822906adcb..f97f272e16ee 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -792,19 +792,19 @@ char * __init efi_md_typeattr_format(char *buf, size_t size,
 }
 
 /*
+ * IA64 has a funky EFI memory map that doesn't work the same way as
+ * other architectures.
+ */
+#ifndef CONFIG_IA64
+/*
  * efi_mem_attributes - lookup memmap attributes for physical address
  * @phys_addr: the physical address to lookup
  *
  * Search in the EFI memory map for the region covering
  * @phys_addr. Returns the EFI memory attributes if the region
  * was found in the memory map, 0 otherwise.
- *
- * Despite being marked __weak, most architectures should *not*
- * override this function. It is __weak solely for the benefit
- * of ia64 which has a funky EFI memory map that doesn't work
- * the same way as other architectures.
  */
-u64 __weak efi_mem_attributes(unsigned long phys_addr)
+u64 efi_mem_attributes(unsigned long phys_addr)
 {
 	efi_memory_desc_t *md;
 
@@ -820,6 +820,31 @@ u64 __weak efi_mem_attributes(unsigned long phys_addr)
 	return 0;
 }
 
+/*
+ * efi_mem_type - lookup memmap type for physical address
+ * @phys_addr: the physical address to lookup
+ *
+ * Search in the EFI memory map for the region covering @phys_addr.
+ * Returns the EFI memory type if the region was found in the memory
+ * map, EFI_RESERVED_TYPE (zero) otherwise.
+ */
+u32 efi_mem_type(unsigned long phys_addr)
+{
+	const efi_memory_desc_t *md;
+
+	if (!efi_enabled(EFI_MEMMAP))
+		return 0;
+
+	for_each_efi_memory_desc(md) {
+		if ((md->phys_addr <= phys_addr) &&
+		    (phys_addr < (md->phys_addr +
+				  (md->num_pages << EFI_PAGE_SHIFT))))
+			return md->type;
+	}
+	return EFI_RESERVED_TYPE;
+}
+#endif
+
 int efi_status_to_err(efi_status_t status)
 {
 	int err;
-- 
2.11.0

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#1720572 — [tip:efi/core] efi: Move efi_mem_type() to common code

Commit-ID:  23f0571c9fd184504f7a2f27011750e0ad99bb73
Gitweb:     http://git.kernel.org/tip/23f0571c9fd184504f7a2f27011750e0ad99bb73
Author:     Jan Beulich <JBeulich@suse.com>
AuthorDate: Fri, 25 Aug 2017 16:50:18 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Sat, 26 Aug 2017 09:20:33 +0200

efi: Move efi_mem_type() to common code

This follows efi_mem_attributes(), as it's similarly generic. Drop
__weak from that one though (and don't introduce it for efi_mem_type()
in the first place) to make clear that other overrides to these
functions are really not intended.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170825155019.6740-5-ard.biesheuvel@linaro.org
[ Resolved conflict with: f99afd08a45f: (efi: Update efi_mem_type() to return an error rather than 0) ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/platform/efi/efi.c | 19 -------------------
 drivers/firmware/efi/efi.c  | 37 +++++++++++++++++++++++++++++++------
 2 files changed, 31 insertions(+), 25 deletions(-)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 6217b23..928b6dc 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -1032,25 +1032,6 @@ void __init efi_enter_virtual_mode(void)
 	efi_dump_pagetable();
 }
 
-/*
- * Convenience functions to obtain memory types and attributes
- */
-int efi_mem_type(unsigned long phys_addr)
-{
-	efi_memory_desc_t *md;
-
-	if (!efi_enabled(EFI_MEMMAP))
-		return -ENOTSUPP;
-
-	for_each_efi_memory_desc(md) {
-		if ((md->phys_addr <= phys_addr) &&
-		    (phys_addr < (md->phys_addr +
-				  (md->num_pages << EFI_PAGE_SHIFT))))
-			return md->type;
-	}
-	return -EINVAL;
-}
-
 static int __init arch_parse_efi_cmdline(char *str)
 {
 	if (!str) {
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index c8a27a2..f70febf 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -811,19 +811,19 @@ char * __init efi_md_typeattr_format(char *buf, size_t size,
 }
 
 /*
+ * IA64 has a funky EFI memory map that doesn't work the same way as
+ * other architectures.
+ */
+#ifndef CONFIG_IA64
+/*
  * efi_mem_attributes - lookup memmap attributes for physical address
  * @phys_addr: the physical address to lookup
  *
  * Search in the EFI memory map for the region covering
  * @phys_addr. Returns the EFI memory attributes if the region
  * was found in the memory map, 0 otherwise.
- *
- * Despite being marked __weak, most architectures should *not*
- * override this function. It is __weak solely for the benefit
- * of ia64 which has a funky EFI memory map that doesn't work
- * the same way as other architectures.
  */
-u64 __weak efi_mem_attributes(unsigned long phys_addr)
+u64 efi_mem_attributes(unsigned long phys_addr)
 {
 	efi_memory_desc_t *md;
 
@@ -839,6 +839,31 @@ u64 __weak efi_mem_attributes(unsigned long phys_addr)
 	return 0;
 }
 
+/*
+ * efi_mem_type - lookup memmap type for physical address
+ * @phys_addr: the physical address to lookup
+ *
+ * Search in the EFI memory map for the region covering @phys_addr.
+ * Returns the EFI memory type if the region was found in the memory
+ * map, EFI_RESERVED_TYPE (zero) otherwise.
+ */
+int efi_mem_type(unsigned long phys_addr)
+{
+	const efi_memory_desc_t *md;
+
+	if (!efi_enabled(EFI_MEMMAP))
+		return -ENOTSUPP;
+
+	for_each_efi_memory_desc(md) {
+		if ((md->phys_addr <= phys_addr) &&
+		    (phys_addr < (md->phys_addr +
+				  (md->num_pages << EFI_PAGE_SHIFT))))
+			return md->type;
+	}
+	return -EINVAL;
+}
+#endif
+
 int efi_status_to_err(efi_status_t status)
 {
 	int err;

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