[tpmdd-devel,v5,3/3] tpm: add securityfs support for TPM 2.0 firmware event log

diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 1dc2671..f185a6a5 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -3,7 +3,7 @@ 
 #
 obj-$(CONFIG_TCG_TPM) += tpm.o
 tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \
-		tpm_eventlog.o tpm_eventlog_init.o
+		tpm_eventlog.o tpm_eventlog_init.o tpm2_eventlog.o
 tpm-$(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/tpm2_eventlog.c b/drivers/char/tpm/tpm2_eventlog.c
new file mode 100644
index 0000000..865e70e
--- /dev/null
+++ b/drivers/char/tpm/tpm2_eventlog.c
@@ -0,0 +1,214 @@ 
+/*
+ * Copyright (C) 2016 IBM Corporation
+ *
+ * Authors:
+ *      Nayna Jain <nayna@linux.vnet.ibm.com>
+ *
+ * Access to TPM 2.0 event log as written by Firmware.
+ * It assumes that writer of event log has followed TCG Spec 2.0
+ * has written the event struct data in little endian. With that,
+ * it doesn't need any endian conversion for structure content.
+ *
+ * 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/seq_file.h>
+#include <linux/fs.h>
+#include <linux/security.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "tpm.h"
+#include "tpm_eventlog.h"
+
+static int calc_tpm2_event_size(struct tcg_pcr_event2 *event,
+		struct tcg_pcr_event *event_header)
+{
+	struct tcg_efi_specid_event *efispecid;
+	struct tcg_event_field *event_field;
+	void *marker, *marker_start;
+	int i, j;
+	u16 halg;
+	u32 halg_size;
+	size_t size = 0;
+
+	/*
+	 * NOTE: TPM 2.0 supports extend to multiple PCR Banks. This implies
+	 * event log also has multiple digest values, one for each PCR Bank.
+	 * This is called Crypto Agile Log Entry Format.
+	 * TCG EFI Protocol Specification defines the procedure to parse
+	 * the event log. Below code implements this procedure to parse
+	 * correctly the Crypto agile log entry format.
+	 * Example of Crypto Agile Log Digests Format :
+	 * digest_values.count = 2;
+	 * digest_values.digest[0].alg_id = sha1;
+	 * digest_values.digest[0].digest.sha1 = {20 bytes raw data};
+	 * digest_values.digest[1].alg_id = sha256;
+	 * digest_values.digest[1].digest.sha256 = {32 bytes raw data};
+	 * Offset of eventsize is sizeof(count) + sizeof(alg_id) + 20
+	 *			+ sizeof(alg_id) + 32;
+	 *
+	 * Since, offset of event_size can vary based on digests count, offset
+	 * has to be calculated at run time. void *marker is used to traverse
+	 * the dynamic structure and calculate the offset of event_size.
+	 */
+
+	marker = event;
+	marker_start = marker;
+	marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type)
+		+ sizeof(event->digests.count);
+
+	efispecid = (struct tcg_efi_specid_event *) event_header->event;
+
+	for (i = 0; (i < event->digests.count) && (i < HASH_COUNT); i++) {
+		halg_size = sizeof(event->digests.digests[i].alg_id);
+		memcpy(&halg, marker, halg_size);
+		marker = marker + halg_size;
+		for (j = 0; (j < efispecid->num_algs); j++) {
+			if (halg == efispecid->digest_sizes[j].alg_id) {
+				marker = marker +
+					efispecid->digest_sizes[j].digest_size;
+				break;
+			}
+		}
+	}
+
+	event_field = (struct tcg_event_field *) marker;
+	marker = marker + sizeof(event_field->event_size)
+		+ event_field->event_size;
+	size = marker - marker_start;
+
+	if ((event->event_type == 0) && (event_field->event_size == 0))
+		return 0;
+
+	return size;
+}
+
+static void *tpm2_bios_measurements_start(struct seq_file *m, loff_t *pos)
+{
+	struct tpm_chip *chip = m->private;
+	struct tpm_bios_log *log = &chip->log;
+	void *addr = log->bios_event_log;
+	void *limit = log->bios_event_log_end;
+	struct tcg_pcr_event *event_header;
+	struct tcg_pcr_event2 *event;
+	int i;
+	size_t size = 0;
+
+	event_header = addr;
+
+	size = sizeof(struct tcg_pcr_event) - sizeof(event_header->event)
+		+ event_header->event_size;
+
+
+	if (*pos == 0) {
+		if (addr + size < limit) {
+			if ((event_header->event_type == 0) &&
+					(event_header->event_size == 0))
+				return NULL;
+			return SEQ_START_TOKEN;
+		}
+	}
+
+	if (*pos > 0) {
+		addr += size;
+		event = addr;
+		size = calc_tpm2_event_size(event, event_header);
+		if ((addr + size >=  limit) || (size == 0))
+			return NULL;
+	}
+
+	/* read over *pos measurements */
+	for (i = 0; i < (*pos - 1); i++) {
+		event = addr;
+		size = calc_tpm2_event_size(event, event_header);
+
+		if ((addr + size >= limit) || (size == 0))
+			return NULL;
+		addr += size;
+	}
+
+	return addr;
+}
+
+static void *tpm2_bios_measurements_next(struct seq_file *m, void *v,
+		loff_t *pos)
+{
+	struct tcg_pcr_event *event_header;
+	struct tcg_pcr_event2 *event;
+	struct tpm_chip *chip = m->private;
+	struct tpm_bios_log *log = &chip->log;
+	void *limit = log->bios_event_log_end;
+	void *marker;
+	size_t event_size = 0;
+
+	event_header = log->bios_event_log;
+
+	if (v == SEQ_START_TOKEN) {
+		event_size = sizeof(struct tcg_pcr_event)
+			- sizeof(event_header->event)
+			+ event_header->event_size;
+		marker = event_header;
+	} else {
+		event = v;
+		event_size = calc_tpm2_event_size(event, event_header);
+		if (event_size == 0)
+			return NULL;
+		marker =  event;
+	}
+
+	marker = marker + event_size;
+	if (marker >= limit)
+		return NULL;
+	v = marker;
+	event = v;
+
+	event_size = calc_tpm2_event_size(event, event_header);
+	if (((v + event_size) >= limit) || (event_size == 0))
+		return NULL;
+
+	(*pos)++;
+	return v;
+}
+
+static void tpm2_bios_measurements_stop(struct seq_file *m, void *v)
+{
+}
+
+static int tpm2_binary_bios_measurements_show(struct seq_file *m, void *v)
+{
+	struct tpm_chip *chip = m->private;
+	struct tpm_bios_log *log = &chip->log;
+	struct tcg_pcr_event *event_header = log->bios_event_log;
+	struct tcg_pcr_event2 *event = v;
+	void *temp_ptr;
+	size_t size = 0;
+
+	if (v == SEQ_START_TOKEN) {
+		size = sizeof(struct tcg_pcr_event)
+			- sizeof(event_header->event)
+			+ event_header->event_size;
+
+		temp_ptr = event_header;
+
+		if (size > 0)
+			seq_write(m, temp_ptr, size);
+	} else {
+		size = calc_tpm2_event_size(event, event_header);
+		temp_ptr = event;
+		if (size > 0)
+			seq_write(m, temp_ptr, size);
+	}
+
+	return 0;
+}
+
+const struct seq_operations tpm2_binary_b_measurements_seqops = {
+	.start = tpm2_bios_measurements_start,
+	.next = tpm2_bios_measurements_next,
+	.stop = tpm2_bios_measurements_stop,
+	.show = tpm2_binary_bios_measurements_show,
+};
diff --git a/drivers/char/tpm/tpm_eventlog.h b/drivers/char/tpm/tpm_eventlog.h
index 155467d..0780f1e 100644
--- a/drivers/char/tpm/tpm_eventlog.h
+++ b/drivers/char/tpm/tpm_eventlog.h
@@ -5,6 +5,9 @@ 
 #define TCG_EVENT_NAME_LEN_MAX	255
 #define MAX_TEXT_EVENT		1000	/* Max event string length */
 #define ACPI_TCPA_SIG		"TCPA"	/* 0x41504354 /'TCPA' */
+#define HASH_COUNT		3
+#define MAX_TPM_LOG_MSG		128
+#define MAX_DIGEST_SIZE		64
 
 #ifdef CONFIG_PPC64
 #define do_endian_conversion(x) be32_to_cpu(x)
@@ -73,8 +76,74 @@  enum tcpa_pc_event_ids {
 	HOST_TABLE_OF_DEVICES,
 };
 
+/*
+ * All the structures related to TPM 2.0 Event Log are taken from TCG EFIi
+ * Protocol * Specification, Family "2.0". Document is available on link
+ * http://www.trustedcomputinggroup.org/tcg-efi-protocol-specification/
+ * Information is also available on TCG PC Client Platform Firmware Profile
+ * Specification, Family "2.0"
+ * Detailed digest structures for TPM 2.0 are defined in document
+ * Trusted Platform Module Library Part 2: Structures, Family "2.0".
+ */
+
+/* TPM 2.0 Event log header algorithm spec. */
+struct tcg_efi_specid_event_algs {
+	u16     alg_id;
+	u16     digest_size;
+} __packed;
+
+/* TPM 2.0 Event log header data. */
+struct tcg_efi_specid_event {
+	u8      signature[16];
+	u32     platform_class;
+	u8      spec_version_minor;
+	u8      spec_version_major;
+	u8      spec_errata;
+	u8      uintnsize;
+	u32     num_algs;
+	struct tcg_efi_specid_event_algs   digest_sizes[HASH_COUNT];
+	u8      vendor_info_size;
+	u8      vendor_info[0];
+} __packed;
+
+/* TPM 2.0 Event Log Header. */
+struct tcg_pcr_event {
+	u32     pcr_idx;
+	u32     event_type;
+	u8      digest[20];
+	u32     event_size;
+	u8      event[MAX_TPM_LOG_MSG];
+} __packed;
+
+/* TPM 2.0 Crypto agile algorithm and respective digest. */
+struct tpmt_ha {
+	u16     alg_id;
+	u8      digest[MAX_DIGEST_SIZE];
+} __packed;
+
+/* TPM 2.0 Crypto agile digests list. */
+struct tpml_digest_values {
+	u32     count;
+	struct tpmt_ha  digests[HASH_COUNT];
+} __packed;
+
+/* TPM 2.0 Event field structure. */
+struct tcg_event_field {
+	u32     event_size;
+	u8      event[MAX_TPM_LOG_MSG];
+} __packed;
+
+/* TPM 2.0 Crypto agile log entry format. */
+struct tcg_pcr_event2 {
+	u32     pcr_idx;
+	u32     event_type;
+	struct tpml_digest_values digests;
+	struct tcg_event_field  event;
+} __packed;
+
 extern const struct seq_operations tpm_ascii_b_measurements_seqops;
 extern const struct seq_operations tpm_binary_b_measurements_seqops;
+extern const struct seq_operations tpm2_binary_b_measurements_seqops;
 
 #if defined(CONFIG_ACPI)
 int tpm_read_log_acpi(struct tpm_chip *chip);
diff --git a/drivers/char/tpm/tpm_eventlog_init.c b/drivers/char/tpm/tpm_eventlog_init.c
index ae42f46..d1fe83e 100644
--- a/drivers/char/tpm/tpm_eventlog_init.c
+++ b/drivers/char/tpm/tpm_eventlog_init.c
@@ -121,9 +121,6 @@  int tpm_bios_log_setup(struct tpm_chip *chip)
 	unsigned int cnt;
 	int rc = 0;
 
-	if (chip->flags & TPM_CHIP_FLAG_TPM2)
-		return 0;
-
 	rc = tpm_read_log(chip);
 	if (rc)
 		return rc;
@@ -135,28 +132,36 @@  int tpm_bios_log_setup(struct tpm_chip *chip)
 	cnt++;
 
 	chip->bin_log_seqops.chip = chip;
-	chip->bin_log_seqops.seqops = &tpm_binary_b_measurements_seqops;
+	if (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],
-				   (void *)&chip->bin_log_seqops,
-				   &tpm_bios_measurements_ops);
+		securityfs_create_file("binary_bios_measurements",
+				       0440, chip->bios_dir[0],
+				       (void *)&chip->bin_log_seqops,
+				       &tpm_bios_measurements_ops);
 	if (is_bad(chip->bios_dir[cnt]))
 		goto err;
 	cnt++;
 
-	chip->ascii_log_seqops.chip = chip;
-	chip->ascii_log_seqops.seqops = &tpm_ascii_b_measurements_seqops;
-
-	chip->bios_dir[cnt] =
-	    securityfs_create_file("ascii_bios_measurements",
-				   0440, chip->bios_dir[0],
-				   (void *)&chip->ascii_log_seqops,
-				   &tpm_bios_measurements_ops);
-	if (is_bad(chip->bios_dir[cnt]))
-		goto err;
-	cnt++;
+	if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
+		chip->ascii_log_seqops.chip = chip;
+		chip->ascii_log_seqops.seqops =
+			&tpm_ascii_b_measurements_seqops;
+
+		chip->bios_dir[cnt] =
+			securityfs_create_file("ascii_bios_measurements",
+					       0440, chip->bios_dir[0],
+					       (void *)&chip->ascii_log_seqops,
+					       &tpm_bios_measurements_ops);
+		if (is_bad(chip->bios_dir[cnt]))
+			goto err;
+		cnt++;
+	}
 
 	return 0;