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authorThiebaud Weksteen <tweek@google.com>2017-09-20 10:13:39 +0200
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2018-01-08 12:58:35 +0200
commit33b6d03469b2206fb51ecc37f40411a857ad8fff (patch)
tree6b0c5cc3fc87cdc3e5f796b55094563fb9c1bf69 /drivers
parent4d01d29d9307d321149ff5ad66d47bee8e56c012 (diff)
efi: call get_event_log before ExitBootServices
With TPM 2.0 specification, the event logs may only be accessible by calling an EFI Boot Service. Modify the EFI stub to copy the log area to a new Linux-specific EFI configuration table so it remains accessible once booted. When calling this service, it is possible to specify the expected format of the logs: TPM 1.2 (SHA1) or TPM 2.0 ("Crypto Agile"). For now, only the first format is retrieved. Signed-off-by: Thiebaud Weksteen <tweek@google.com> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Tested-by: Javier Martinez Canillas <javierm@redhat.com> Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/firmware/efi/Makefile2
-rw-r--r--drivers/firmware/efi/efi.c4
-rw-r--r--drivers/firmware/efi/libstub/Makefile3
-rw-r--r--drivers/firmware/efi/libstub/tpm.c81
-rw-r--r--drivers/firmware/efi/tpm.c40
5 files changed, 127 insertions, 3 deletions
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index 269501dfba53..1d7226fb7d2f 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -11,7 +11,7 @@
KASAN_SANITIZE_runtime-wrappers.o := n
obj-$(CONFIG_ACPI_BGRT) += efi-bgrt.o
-obj-$(CONFIG_EFI) += efi.o vars.o reboot.o memattr.o
+obj-$(CONFIG_EFI) += efi.o vars.o reboot.o memattr.o tpm.o
obj-$(CONFIG_EFI) += capsule.o memmap.o
obj-$(CONFIG_EFI_VARS) += efivars.o
obj-$(CONFIG_EFI_ESRT) += esrt.o
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 557a47829d03..cfa6fe786ab6 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);
@@ -464,6 +465,7 @@ 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},
};
@@ -552,6 +554,8 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz,
if (efi_enabled(EFI_MEMMAP))
efi_memattr_init();
+ efi_tpm_eventlog_init();
+
/* Parse the EFI Properties table if it exists */
if (efi.properties_table != EFI_INVALID_TABLE_ADDR) {
efi_properties_table_t *tbl;
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index adaa4a964f0c..7b3ba40f0745 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -30,8 +30,7 @@ OBJECT_FILES_NON_STANDARD := y
# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
KCOV_INSTRUMENT := n
-lib-y := efi-stub-helper.o gop.o secureboot.o
-lib-$(CONFIG_RESET_ATTACK_MITIGATION) += tpm.o
+lib-y := efi-stub-helper.o gop.o secureboot.o tpm.o
# include the stub's generic dependencies from lib/ when building for ARM/arm64
arm-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c
diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c
index 6224cdbc9669..da661bf8cb96 100644
--- a/drivers/firmware/efi/libstub/tpm.c
+++ b/drivers/firmware/efi/libstub/tpm.c
@@ -4,15 +4,18 @@
* Copyright (C) 2016 CoreOS, Inc
* Copyright (C) 2017 Google, Inc.
* Matthew Garrett <mjg59@google.com>
+ * Thiebaud Weksteen <tweek@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 <linux/tpm_eventlog.h>
#include <asm/efi.h>
#include "efistub.h"
+#ifdef CONFIG_RESET_ATTACK_MITIGATION
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',
@@ -56,3 +59,81 @@ void efi_enable_reset_attack_mitigation(efi_system_table_t *sys_table_arg)
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS, sizeof(val), &val);
}
+
+#endif
+
+void efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg)
+{
+ efi_guid_t tcg2_guid = EFI_TCG2_PROTOCOL_GUID;
+ efi_guid_t linux_eventlog_guid = LINUX_EFI_TPM_EVENT_LOG_GUID;
+ efi_status_t status;
+ efi_physical_addr_t log_location, log_last_entry;
+ struct linux_efi_tpm_eventlog *log_tbl;
+ unsigned long first_entry_addr, last_entry_addr;
+ size_t log_size, last_entry_size;
+ efi_bool_t truncated;
+ void *tcg2_protocol;
+
+ status = efi_call_early(locate_protocol, &tcg2_guid, NULL,
+ &tcg2_protocol);
+ if (status != EFI_SUCCESS)
+ return;
+
+ status = efi_call_proto(efi_tcg2_protocol, get_event_log, tcg2_protocol,
+ EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2,
+ &log_location, &log_last_entry, &truncated);
+ if (status != EFI_SUCCESS)
+ return;
+
+ if (!log_location)
+ return;
+ first_entry_addr = (unsigned long) log_location;
+
+ /*
+ * We populate the EFI table even if the logs are empty.
+ */
+ if (!log_last_entry) {
+ log_size = 0;
+ } else {
+ last_entry_addr = (unsigned long) log_last_entry;
+ /*
+ * get_event_log only returns the address of the last entry.
+ * We need to calculate its size to deduce the full size of
+ * the logs.
+ */
+ last_entry_size = sizeof(struct tcpa_event) +
+ ((struct tcpa_event *) last_entry_addr)->event_size;
+ log_size = log_last_entry - log_location + last_entry_size;
+ }
+
+ /* Allocate space for the logs and copy them. */
+ status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
+ sizeof(*log_tbl) + log_size,
+ (void **) &log_tbl);
+
+ if (status != EFI_SUCCESS) {
+ efi_printk(sys_table_arg,
+ "Unable to allocate memory for event log\n");
+ return;
+ }
+
+ memset(log_tbl, 0, sizeof(*log_tbl) + log_size);
+ log_tbl->size = log_size;
+ log_tbl->version = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
+ memcpy(log_tbl->log, (void *) first_entry_addr, log_size);
+
+ status = efi_call_early(install_configuration_table,
+ &linux_eventlog_guid, log_tbl);
+ if (status != EFI_SUCCESS)
+ goto err_free;
+ return;
+
+err_free:
+ efi_call_early(free_pool, log_tbl);
+}
+
+void efi_retrieve_tpm2_eventlog(efi_system_table_t *sys_table_arg)
+{
+ /* Only try to retrieve the logs in 1.2 format. */
+ efi_retrieve_tpm2_eventlog_1_2(sys_table_arg);
+}
diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c
new file mode 100644
index 000000000000..0cbeb3d46b18
--- /dev/null
+++ b/drivers/firmware/efi/tpm.c
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2017 Google, Inc.
+ * 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 version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/efi.h>
+#include <linux/init.h>
+#include <linux/memblock.h>
+
+#include <asm/early_ioremap.h>
+
+/*
+ * Reserve the memory associated with the TPM Event Log configuration table.
+ */
+int __init efi_tpm_eventlog_init(void)
+{
+ struct linux_efi_tpm_eventlog *log_tbl;
+ unsigned int tbl_size;
+
+ if (efi.tpm_log == EFI_INVALID_TABLE_ADDR)
+ return 0;
+
+ log_tbl = early_memremap(efi.tpm_log, sizeof(*log_tbl));
+ if (!log_tbl) {
+ pr_err("Failed to map TPM Event Log table @ 0x%lx\n",
+ efi.tpm_log);
+ efi.tpm_log = EFI_INVALID_TABLE_ADDR;
+ return -ENOMEM;
+ }
+
+ tbl_size = sizeof(*log_tbl) + log_tbl->size;
+ memblock_reserve(efi.tpm_log, tbl_size);
+ early_memunmap(log_tbl, sizeof(*log_tbl));
+ return 0;
+}
+