SME EFI table updates/fixes

PATCH In review Tom Lendacky 2 participants 4 messages Feb 25, 2020

Subsystems (4)

Stable branch x86 x86 platform drivers EFI

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Tom Lendacky

author

2020-02-25 20:34 UTC #0 lore raw

v3 cover SME EFI table updates/fixes

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(-)

Signature · 1 line

2.17.1

Tom Lendacky

author

2020-02-25 20:34 UTC #1 lore raw

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

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 <[email protected]> # 5.4.x-

Signed-off-by Tom Lendacky <[email protected]>

---
 arch/x86/platform/efi/efi.c | 2 ++
 1 file changed, 2 insertions(+)

arch/x86/platform/efi/efi.c +2 -0

index 43b24e149312..0a8117865430 100644
@@ -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 */

Signature · 1 line

2.17.1

Tom Lendacky

author

2020-02-25 20:34 UTC #2 lore raw

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

In reply to Tom Lendacky

Signed-off-by Tom Lendacky <[email protected]>

---
 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(-)

arch/x86/platform/efi/efi.c +1 -0

index 0a8117865430..aca9bdd87bca 100644
@@ -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 */

drivers/firmware/efi/efi.c +10 -8

index 69a585106d30..1e79f77d4e6c 100644
@@ -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);
 }

include/linux/efi.h +2 -0

index 2ab33d5d6ca5..e8a08a499131 100644
@@ -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:
  */

Signature · 1 line

2.17.1

Ard Biesheuvel

maintainer

2020-02-25 20:38 UTC #3 lore raw

In reply to Tom Lendacky

Quoted 15 lines · 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")

Quoted 9 lines

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.