Thread (9 messages) 9 messages, 3 authors, 2020-06-25

Re: [PATCH v5 1/2] acpi: Extend TPM2 ACPI table with missing log fields

From: Jarkko Sakkinen <hidden>
Date: 2020-06-25 00:00:31
Also in: linux-acpi, linux-security-module, lkml

On Tue, Jun 23, 2020 at 08:06:35AM -0400, Stefan Berger wrote:
From: Stefan Berger <stefanb@linux.ibm.com>

Recent extensions of the TPM2 ACPI table added 3 more fields
including 12 bytes of start method specific parameters and Log Area
Minimum Length (u32) and Log Area Start Address (u64). So, we extend
the existing structure with these fields to allow non-UEFI systems
to access the TPM2's log.

The specification that has the new fields is the following:
  TCG ACPI Specification
  Family "1.2" and "2.0"
  Version 1.2, Revision 8

Adapt all existing table size calculations to use
offsetof(struct acpi_table_tpm2, start_method_specific)
[where start_method_specific is a newly added field]
rather than sizeof(struct acpi_table_tpm2) so that the addition
of the new fields does not affect current systems that may not
have them.
I found at least one regression from this patch. Please remove my
reviewed-by comment form the next version.

Should have:

  Link: https://trustedcomputinggroup.org/wp-content/uploads/TCG_ACPIGeneralSpecification_v1.20_r8.pdf

Please, add this.
quoted hunk ↗ jump to hunk
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Cc: linux-acpi@vger.kernel.org
Acked-by: Rafael J. Wysocki <redacted>
Reviewed-by: Jarkko Sakkinen <redacted>
---
 drivers/char/tpm/tpm_crb.c | 13 ++++++++++---
 drivers/char/tpm/tpm_tis.c |  4 +++-
 include/acpi/actbl3.h      |  5 +++--
 3 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index a9dcf31eadd2..0565aa5482f9 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -669,7 +669,9 @@ static int crb_acpi_add(struct acpi_device *device)
 
 	status = acpi_get_table(ACPI_SIG_TPM2, 1,
 				(struct acpi_table_header **) &buf);
-	if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
+	if (ACPI_FAILURE(status) || buf->header.length <
+			offsetof(struct acpi_table_tpm2,
+				 start_method_specific)) {
 		dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
 		return -EINVAL;
 	}
@@ -684,14 +686,19 @@ static int crb_acpi_add(struct acpi_device *device)
 		return -ENOMEM;
 
 	if (sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC) {
-		if (buf->header.length < (sizeof(*buf) + sizeof(*crb_smc))) {
+		if (buf->header.length <
+			(offsetof(struct acpi_table_tpm2,
+				  start_method_specific) +
Should be

  offsetof(struct acpti_table_tpm2, log_area_minimum_length)
quoted hunk ↗ jump to hunk
+			 sizeof(*crb_smc))) {
 			dev_err(dev,
 				FW_BUG "TPM2 ACPI table has wrong size %u for start method type %d\n",
 				buf->header.length,
 				ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC);
 			return -EINVAL;
 		}
-		crb_smc = ACPI_ADD_PTR(struct tpm2_crb_smc, buf, sizeof(*buf));
+		crb_smc = ACPI_ADD_PTR(struct tpm2_crb_smc, buf,
+			   offsetof(struct acpi_table_tpm2,
+				    start_method_specific));
 		priv->smc_func_id = crb_smc->smc_func_id;
 	}
 
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index e7df342a317d..a80f36860bac 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -111,7 +111,9 @@ static int check_acpi_tpm2(struct device *dev)
 	 */
 	st =
 	    acpi_get_table(ACPI_SIG_TPM2, 1, (struct acpi_table_header **)&tbl);
-	if (ACPI_FAILURE(st) || tbl->header.length < sizeof(*tbl)) {
+	if (ACPI_FAILURE(st) || tbl->header.length <
+			offsetof(struct acpi_table_tpm2,
+				 start_method_specific)) {
 		dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
 		return -EINVAL;
 	}
diff --git a/include/acpi/actbl3.h b/include/acpi/actbl3.h
index b0b163b9efc6..8b55426bbcf6 100644
--- a/include/acpi/actbl3.h
+++ b/include/acpi/actbl3.h
@@ -411,8 +411,9 @@ struct acpi_table_tpm2 {
 	u16 reserved;
 	u64 control_address;
 	u32 start_method;
-
-	/* Platform-specific data follows */
+	u8  start_method_specific[12];
+	u32 log_area_minimum_length;		/* optional */
+	u64 log_area_start_address;		/* optional */
'start_method_specific' is also optional. Please remove the optional
comments altogether as platform-specific data is by definition optional.
 };
 
 /* Values for start_method above */
-- 
2.26.2
Please add this to the next version since we do not want to break ARM
side:

  Cc: Jiandi An [off-list ref]

/Jarkko
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