[PATCH v3 0/2] SME EFI table updates/fixes

[PATCH v3 0/2] SME EFI table updates/fixes

[Tom Lendacky]

This patch series adds new EFI tables to the list of tables that are
to be mapped unencrypted when SME is active

- EFI TPM log and TPM final log tables
- EFI RNG seed table

---

Patches based on
  git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git next

and commit:
  dc235d62fc60 ("efi: Bump the Linux EFI stub major version number to #1")

Changes since v2:
- Split the patch into TPM related and RNG related patches
- Account for the moving of the RNG seed EFI table from struct efi
  to a static variable

Tom Lendacky (2):
  x86/efi: Add TPM related EFI tables to unencrypted mapping checks
  x86/efi: Add RNG seed EFI table to unencrypted mapping check

 arch/x86/platform/efi/efi.c |  3 +++
 drivers/firmware/efi/efi.c  | 18 ++++++++++--------
 include/linux/efi.h         |  2 ++
 3 files changed, 15 insertions(+), 8 deletions(-)

-- 
2.17.1

[PATCH v3 1/2] x86/efi: Add TPM related EFI tables to unencrypted mapping checks

[Tom Lendacky]

When booting with SME active, EFI tables must be mapped unencrypted since
they were built by UEFI in unencrypted memory. Update the list of tables
to be checked during early_memremap() processing to account for the EFI
TPM tables.

This fixes a bug where an EFI TPM log table has been created by UEFI, but
it lives in memory that has been marked as usable rather than reserved.

Cc: <stable@vger.kernel.org> # 5.4.x-
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/platform/efi/efi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 43b24e149312..0a8117865430 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -88,6 +88,8 @@ static const unsigned long * const efi_tables[] = {
 #ifdef CONFIG_EFI_RCI2_TABLE
 	&rci2_table_phys,
 #endif
+	&efi.tpm_log,
+	&efi.tpm_final_log,
 };
 
 u64 efi_setup;		/* efi setup_data physical address */
-- 
2.17.1

[PATCH v3 2/2] x86/efi: Add RNG seed EFI table to unencrypted mapping check

[Tom Lendacky]

When booting with SME active, EFI tables must be mapped unencrypted since
they were built by UEFI in unencrypted memory. Update the list of tables
to be checked during early_memremap() processing to account for the EFI
RNG seed table.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/platform/efi/efi.c |  1 +
 drivers/firmware/efi/efi.c  | 18 ++++++++++--------
 include/linux/efi.h         |  2 ++
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 0a8117865430..aca9bdd87bca 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -90,6 +90,7 @@ static const unsigned long * const efi_tables[] = {
 #endif
 	&efi.tpm_log,
 	&efi.tpm_final_log,
+	&efi_rng_seed,
 };
 
 u64 efi_setup;		/* efi setup_data physical address */
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 69a585106d30..1e79f77d4e6c 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -45,7 +45,7 @@ struct efi __read_mostly efi = {
 };
 EXPORT_SYMBOL(efi);
 
-static unsigned long __ro_after_init rng_seed = EFI_INVALID_TABLE_ADDR;
+unsigned long __ro_after_init efi_rng_seed = EFI_INVALID_TABLE_ADDR;
 static unsigned long __initdata mem_reserve = EFI_INVALID_TABLE_ADDR;
 static unsigned long __initdata rt_prop = EFI_INVALID_TABLE_ADDR;
 
@@ -451,7 +451,7 @@ static const efi_config_table_type_t common_tables[] __initconst = {
 	{SMBIOS3_TABLE_GUID, "SMBIOS 3.0", &efi.smbios3},
 	{EFI_SYSTEM_RESOURCE_TABLE_GUID, "ESRT", &efi.esrt},
 	{EFI_MEMORY_ATTRIBUTES_TABLE_GUID, "MEMATTR", &efi_mem_attr_table},
-	{LINUX_EFI_RANDOM_SEED_TABLE_GUID, "RNG", &rng_seed},
+	{LINUX_EFI_RANDOM_SEED_TABLE_GUID, "RNG", &efi_rng_seed},
 	{LINUX_EFI_TPM_EVENT_LOG_GUID, "TPMEventLog", &efi.tpm_log},
 	{LINUX_EFI_TPM_FINAL_LOG_GUID, "TPMFinalLog", &efi.tpm_final_log},
 	{LINUX_EFI_MEMRESERVE_TABLE_GUID, "MEMRESERVE", &mem_reserve},
@@ -519,11 +519,11 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables,
 	pr_cont("\n");
 	set_bit(EFI_CONFIG_TABLES, &efi.flags);
 
-	if (rng_seed != EFI_INVALID_TABLE_ADDR) {
+	if (efi_rng_seed != EFI_INVALID_TABLE_ADDR) {
 		struct linux_efi_random_seed *seed;
 		u32 size = 0;
 
-		seed = early_memremap(rng_seed, sizeof(*seed));
+		seed = early_memremap(efi_rng_seed, sizeof(*seed));
 		if (seed != NULL) {
 			size = seed->size;
 			early_memunmap(seed, sizeof(*seed));
@@ -531,7 +531,8 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables,
 			pr_err("Could not map UEFI random seed!\n");
 		}
 		if (size > 0) {
-			seed = early_memremap(rng_seed, sizeof(*seed) + size);
+			seed = early_memremap(efi_rng_seed,
+					      sizeof(*seed) + size);
 			if (seed != NULL) {
 				pr_notice("seeding entropy pool\n");
 				add_bootloader_randomness(seed->bits, seed->size);
@@ -923,7 +924,7 @@ static int update_efi_random_seed(struct notifier_block *nb,
 	if (!kexec_in_progress)
 		return NOTIFY_DONE;
 
-	seed = memremap(rng_seed, sizeof(*seed), MEMREMAP_WB);
+	seed = memremap(efi_rng_seed, sizeof(*seed), MEMREMAP_WB);
 	if (seed != NULL) {
 		size = min(seed->size, EFI_RANDOM_SEED_SIZE);
 		memunmap(seed);
@@ -931,7 +932,8 @@ static int update_efi_random_seed(struct notifier_block *nb,
 		pr_err("Could not map UEFI random seed!\n");
 	}
 	if (size > 0) {
-		seed = memremap(rng_seed, sizeof(*seed) + size, MEMREMAP_WB);
+		seed = memremap(efi_rng_seed, sizeof(*seed) + size,
+				MEMREMAP_WB);
 		if (seed != NULL) {
 			seed->size = size;
 			get_random_bytes(seed->bits, seed->size);
@@ -949,7 +951,7 @@ static struct notifier_block efi_random_seed_nb = {
 
 static int __init register_update_efi_random_seed(void)
 {
-	if (rng_seed == EFI_INVALID_TABLE_ADDR)
+	if (efi_rng_seed == EFI_INVALID_TABLE_ADDR)
 		return 0;
 	return register_reboot_notifier(&efi_random_seed_nb);
 }
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 2ab33d5d6ca5..e8a08a499131 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -526,6 +526,8 @@ typedef struct {
 	efi_time_t time_of_revocation;
 } efi_cert_x509_sha256_t;
 
+extern unsigned long __ro_after_init efi_rng_seed;		/* RNG Seed table */
+
 /*
  * All runtime access to EFI goes through this structure:
  */
-- 
2.17.1

Re: [PATCH v3 0/2] SME EFI table updates/fixes

[Ard Biesheuvel]

On Tue, 25 Feb 2020 at 21:34, Tom Lendacky <thomas.lendacky@amd.com> wrote:
>
> This patch series adds new EFI tables to the list of tables that are
> to be mapped unencrypted when SME is active
>
> - EFI TPM log and TPM final log tables
> - EFI RNG seed table
>
> ---
>
> Patches based on
>   git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git next
>
> and commit:
>   dc235d62fc60 ("efi: Bump the Linux EFI stub major version number to #1")
>
> Changes since v2:
> - Split the patch into TPM related and RNG related patches
> - Account for the moving of the RNG seed EFI table from struct efi
>   to a static variable
>
> Tom Lendacky (2):
>   x86/efi: Add TPM related EFI tables to unencrypted mapping checks
>   x86/efi: Add RNG seed EFI table to unencrypted mapping check
>

Thanks Tom. I'll queue these up.