[PATCH 2/2] tpm: surface TPM event log based on EFI table

Thiebaud Weksteen
2017-09-06T14:26:13Z

Signed-off-by: Thiebaud Weksteen <tweek@google.com>
---
drivers/char/tpm/Makefile | 2 +-
drivers/char/tpm/tpm.h | 8 +++++
drivers/char/tpm/tpm1_eventlog.c | 16 +++++++---
drivers/char/tpm/tpm_efi.c | 66 ++++++++++++++++++++++++++++++++++++++++
drivers/char/tpm/tpm_eventlog.h | 1 -
drivers/firmware/efi/efi.c | 2 ++
include/linux/efi.h | 1 +
7 files changed, 90 insertions(+), 6 deletions(-)
create mode 100644 drivers/char/tpm/tpm_efi.c

diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 23681f01f95a..74182a63eef2 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -4,7 +4,7 @@
obj-$(CONFIG_TCG_TPM) += tpm.o
tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \
tpm-dev-common.o tpmrm-dev.o tpm1_eventlog.o tpm2_eventlog.o \
- tpm2-space.o
+ tpm2-space.o tpm_efi.o
tpm-$(CONFIG_ACPI) += tpm_ppi.o tpm_acpi.o
tpm-$(CONFIG_OF) += tpm_of.o
obj-$(CONFIG_TCG_TIS_CORE) += tpm_tis_core.o
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index efede7dc9340..8858b6467c0d 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -597,6 +597,14 @@ static inline int tpm_read_log_of(struct tpm_chip *chip)
return -ENODEV;
}
#endif
+#if defined(CONFIG_EFI)
+int tpm_read_log_efi(struct tpm_chip *chip);
+#else
+static inline int tpm_read_log_efi(struct tpm_chip *chip)
+{
+ return -ENODEV;
+}
+#endif

int tpm_bios_log_setup(struct tpm_chip *chip);
void tpm_bios_log_teardown(struct tpm_chip *chip);
diff --git a/drivers/char/tpm/tpm1_eventlog.c b/drivers/char/tpm/tpm1_eventlog.c
index 9a8605e500b5..c7d9b10de97f 100644
--- a/drivers/char/tpm/tpm1_eventlog.c
+++ b/drivers/char/tpm/tpm1_eventlog.c
@@ -21,6 +21,7 @@
*/

#include <linux/seq_file.h>
+#include <linux/efi.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/module.h>
@@ -368,6 +369,10 @@ static int tpm_read_log(struct tpm_chip *chip)
}

rc = tpm_read_log_acpi(chip);
+ if (rc != -ENODEV && rc != -EIO)
+ return rc;
+
+ rc = tpm_read_log_efi(chip);
if (rc != -ENODEV)
return rc;

@@ -388,11 +393,13 @@ int tpm_bios_log_setup(struct tpm_chip *chip)
{
const char *name = dev_name(&chip->dev);
unsigned int cnt;
- int rc = 0;
+ int rc = 0, log_version;
+

rc = tpm_read_log(chip);
- if (rc)
+ if (rc < 0)
return rc;
+ log_version = rc;

cnt = 0;
chip->bios_dir[cnt] = securityfs_create_dir(name, NULL);
@@ -404,14 +411,15 @@ int tpm_bios_log_setup(struct tpm_chip *chip)
cnt++;

chip->bin_log_seqops.chip = chip;
- if (chip->flags & TPM_CHIP_FLAG_TPM2)
+
+ if (log_version == EFI_TCG2_EVENT_LOG_FORMAT_TCG_2 ||
+ (!log_version && (chip->flags & TPM_CHIP_FLAG_TPM2)))
chip->bin_log_seqops.seqops =
&tpm2_binary_b_measurements_seqops;
else
chip->bin_log_seqops.seqops =
&tpm_binary_b_measurements_seqops;

-
chip->bios_dir[cnt] =
securityfs_create_file("binary_bios_measurements",
0440, chip->bios_dir[0],
diff --git a/drivers/char/tpm/tpm_efi.c b/drivers/char/tpm/tpm_efi.c
new file mode 100644
index 000000000000..0ff070e5b4df
--- /dev/null
+++ b/drivers/char/tpm/tpm_efi.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2017 Google
+ *
+ * Authors:
+ * Thiebaud Weksteen <tweek@google.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/efi.h>
+
+#include "tpm.h"
+#include "tpm_eventlog.h"
+
+
+/* read binary bios log from EFI configuration table */
+int tpm_read_log_efi(struct tpm_chip *chip)
+{
+
+ struct linux_efi_tpm_eventlog *log_tbl;
+ struct tpm_bios_log *log;
+ u32 log_size;
+ u8 tpm_log_version;
+
+ if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
+ return -ENODEV;
+
+ if (efi.tpm_log == EFI_INVALID_TABLE_ADDR)
+ return -ENODEV;
+
+ log = &chip->log;
+
+ log_tbl = ioremap(efi.tpm_log, sizeof(*log_tbl));
+ if (!log_tbl) {
+ pr_err("Could not map UEFI TPM log table !\n");
+ return -ENOMEM;
+ }
+
+ log_size = log_tbl->size;
+ iounmap(log_tbl);
+
+ log_tbl = ioremap(efi.tpm_log, sizeof(*log_tbl) + log_size);
+ if (!log_tbl) {
+ pr_err("Could not map UEFI TPM log table payload!\n");
+ return -ENOMEM;
+ }
+
+ /* malloc EventLog space */
+ log->bios_event_log = kmalloc(log_size, GFP_KERNEL);
+ if (!log->bios_event_log)
+ goto err_iounmap;
+ memcpy(log->bios_event_log, log_tbl->log, log_size);
+ log->bios_event_log_end = log->bios_event_log + log_size;
+
+ tpm_log_version = log_tbl->version;
+ iounmap(log_tbl);
+ return tpm_log_version;
+
+err_iounmap:
+ iounmap(log_tbl);
+ return -ENOMEM;
+}
diff --git a/drivers/char/tpm/tpm_eventlog.h b/drivers/char/tpm/tpm_eventlog.h
index 1009a2503985..9144a8707d70 100644
--- a/drivers/char/tpm/tpm_eventlog.h
+++ b/drivers/char/tpm/tpm_eventlog.h
@@ -117,5 +117,4 @@ struct tcg_pcr_event2 {
struct tcg_event_field event;
} __packed;

-
#endif
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index f97f272e16ee..886f67f7519e 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -52,6 +52,7 @@ struct efi __read_mostly efi = {
.properties_table = EFI_INVALID_TABLE_ADDR,
.mem_attr_table = EFI_INVALID_TABLE_ADDR,
.rng_seed = EFI_INVALID_TABLE_ADDR,
+ .tpm_log = EFI_INVALID_TABLE_ADDR
};
EXPORT_SYMBOL(efi);

@@ -444,6 +445,7 @@ static __initdata efi_config_table_type_t common_tables[] = {
{EFI_PROPERTIES_TABLE_GUID, "PROP", &efi.properties_table},
{EFI_MEMORY_ATTRIBUTES_TABLE_GUID, "MEMATTR", &efi.mem_attr_table},
{LINUX_EFI_RANDOM_SEED_TABLE_GUID, "RNG", &efi.rng_seed},
+ {LINUX_EFI_TPM_EVENT_LOG_GUID, "TPMEventLog", &efi.tpm_log},
{NULL_GUID, NULL, NULL},
};

diff --git a/include/linux/efi.h b/include/linux/efi.h
index 5eaaa68ac58a..277a2347fa34 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -930,6 +930,7 @@ extern struct efi {
unsigned long properties_table; /* properties table */
unsigned long mem_attr_table; /* memory attributes table */
unsigned long rng_seed; /* UEFI firmware random seed */
+ unsigned long tpm_log; /* TPM2 Event Log table */
efi_get_time_t *get_time;
efi_set_time_t *set_time;
efi_get_wakeup_time_t *get_wakeup_time;
--
2.14.1.581.gf28d330327-goog