Message-ID: <20170125133208.c7cgpl6ycwidhjy4@intel.com>
Date:   Wed, 25 Jan 2017 15:32:08 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Nayna <nayna@...ux.vnet.ibm.com>
Cc:     tpmdd-devel@...ts.sourceforge.net, peterhuewe@....de,
        tpmdd@...horst.net, jgunthorpe@...idianresearch.com,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v9 2/2] tpm: add securityfs support for TPM 2.0 firmware
 event log

On Tue, Jan 24, 2017 at 03:41:22PM +0530, Nayna wrote:
> 
> 
> On 01/23/2017 08:43 PM, Jarkko Sakkinen wrote:
> > On Mon, Jan 23, 2017 at 02:26:27AM -0500, Nayna Jain wrote:
> > > Unlike the device driver support for TPM 1.2, the TPM 2.0 does
> > > not support the securityfs pseudo files for displaying the
> > > firmware event log.
> > > 
> > > This patch enables support for providing the TPM 2.0 event log in
> > > binary form. TPM 2.0 event log supports a crypto agile format that
> > > records multiple digests, which is different from TPM 1.2. This
> > > patch enables the tpm_bios_log_setup for TPM 2.0  and adds the
> > > event log parser which understand the TPM 2.0 crypto agile format.
> > > 
> > > Signed-off-by: Nayna Jain <nayna@...ux.vnet.ibm.com>
> > > ---
> > >   drivers/char/tpm/Makefile                          |   2 +-
> > >   .../char/tpm/{tpm_eventlog.c => tpm1_eventlog.c}   |  35 ++--
> > >   drivers/char/tpm/tpm2_eventlog.c                   | 203 +++++++++++++++++++++
> > >   drivers/char/tpm/tpm_acpi.c                        |   3 +
> > >   drivers/char/tpm/tpm_eventlog.h                    |  59 ++++++
> > >   5 files changed, 287 insertions(+), 15 deletions(-)
> > >   rename drivers/char/tpm/{tpm_eventlog.c => tpm1_eventlog.c} (95%)
> > >   create mode 100644 drivers/char/tpm/tpm2_eventlog.c
> > > 
> > > diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
> > > index a05b1eb..3d386a8 100644
> > > --- a/drivers/char/tpm/Makefile
> > > +++ b/drivers/char/tpm/Makefile
> > > @@ -3,7 +3,7 @@
> > >   #
> > >   obj-$(CONFIG_TCG_TPM) += tpm.o
> > >   tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \
> > > -		tpm_eventlog.o
> > > +		tpm1_eventlog.o tpm2_eventlog.o
> > >   tpm-$(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/tpm_eventlog.c b/drivers/char/tpm/tpm1_eventlog.c
> > > similarity index 95%
> > > rename from drivers/char/tpm/tpm_eventlog.c
> > > rename to drivers/char/tpm/tpm1_eventlog.c
> > > index 11bb113..9a8605e 100644
> > > --- a/drivers/char/tpm/tpm_eventlog.c
> > > +++ b/drivers/char/tpm/tpm1_eventlog.c
> > > @@ -390,9 +390,6 @@ 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;
> > > @@ -407,7 +404,13 @@ 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",
> > > @@ -418,17 +421,21 @@ int tpm_bios_log_setup(struct tpm_chip *chip)
> > >   		goto err;
> > >   	cnt++;
> > > 
> > > -	chip->ascii_log_seqops.chip = chip;
> > > -	chip->ascii_log_seqops.seqops = &tpm_ascii_b_measurements_seqops;
> > > +	if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
> > > 
> > > -	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_ERR(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_ERR(chip->bios_dir[cnt]))
> > > +			goto err;
> > > +		cnt++;
> > > +	}
> > > 
> > >   	return 0;
> > > 
> > > diff --git a/drivers/char/tpm/tpm2_eventlog.c b/drivers/char/tpm/tpm2_eventlog.c
> > > new file mode 100644
> > > index 0000000..513897c
> > > --- /dev/null
> > > +++ b/drivers/char/tpm/tpm2_eventlog.c
> > > @@ -0,0 +1,203 @@
> > > +/*
> > > + * Copyright (C) 2016 IBM Corporation
> > > + *
> > > + * Authors:
> > > + *      Nayna Jain <nayna@...ux.vnet.ibm.com>
> > > + *
> > > + * Access to TPM 2.0 event log as written by Firmware.
> > > + * It assumes that writer of event log has followed TCG Specification
> > > + * for Family "2.0" and written the event 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"
> > > +
> > > +/*
> > > + * calc_tpm2_event_size() - calculate the event size, where event
> > > + * is an entry in the TPM 2.0 event log. The event is of type Crypto
> > > + * Agile Log Entry Format as defined in TCG EFI Protocol Specification
> > > + * Family "2.0".
> > > +
> > > + * @event: event whose size is to be calculated.
> > > + * @event_header: the first event in the event log.
> > > + *
> > > + * Returns size of the event. If it is an invalid event, returns 0.
> > > + */
> > > +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;
> > > +	void *marker_start;
> > > +	u32 halg_size;
> > > +	size_t size;
> > > +	u16 halg;
> > > +	int i;
> > > +	int j;
> > > +
> > > +	marker = event;
> > > +	marker_start = marker;
> > > +	marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type)
> > > +		+ sizeof(event->count);
> > > +
> > > +	efispecid = (struct tcg_efi_specid_event *)event_header->event;
> > > +
> > > +	for (i = 0; (i < event->count) && (i < TPM2_ACTIVE_PCR_BANKS);
> > > +	     i++) {
> > > +		halg_size = sizeof(event->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;
> > > +	size_t size;
> > > +	int i;
> > > +
> > > +	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;
> > > +	}
> > > +
> > > +	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;
> > > +	size_t event_size;
> > > +	void *marker;
> > > +
> > > +	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;
> > > +
> > > +	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_acpi.c b/drivers/char/tpm/tpm_acpi.c
> > > index b7718c9..169edf3 100644
> > > --- a/drivers/char/tpm/tpm_acpi.c
> > > +++ b/drivers/char/tpm/tpm_acpi.c
> > > @@ -54,6 +54,9 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
> > >   	u64 len, start;
> > >   	struct tpm_bios_log *log;
> > > 
> > > +	if (chip->flags & TPM_CHIP_FLAG_TPM2)
> > > +		return -ENODEV;
> > > +
> > >   	log = &chip->log;
> > > 
> > >   	/* Unfortuntely ACPI does not associate the event log with a specific
> > > diff --git a/drivers/char/tpm/tpm_eventlog.h b/drivers/char/tpm/tpm_eventlog.h
> > > index 1660d74..8d43328 100644
> > > --- a/drivers/char/tpm/tpm_eventlog.h
> > > +++ b/drivers/char/tpm/tpm_eventlog.h
> > > @@ -2,9 +2,12 @@
> > >   #ifndef __TPM_EVENTLOG_H__
> > >   #define __TPM_EVENTLOG_H__
> > > 
> > > +#include <crypto/hash_info.h>
> > > +
> > >   #define TCG_EVENT_NAME_LEN_MAX	255
> > >   #define MAX_TEXT_EVENT		1000	/* Max event string length */
> > >   #define ACPI_TCPA_SIG		"TCPA"	/* 0x41504354 /'TCPA' */
> > > +#define TPM2_ACTIVE_PCR_BANKS	3
> > > 
> > >   #ifdef CONFIG_PPC64
> > >   #define do_endian_conversion(x) be32_to_cpu(x)
> > > @@ -73,6 +76,62 @@ enum tcpa_pc_event_ids {
> > >   	HOST_TABLE_OF_DEVICES,
> > >   };
> > > 
> > > +/*
> > > + * All the structures related to TPM 2.0 Event Log are taken from TCG EFI
> > > + * 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".
> > > + */
> > 
> > I think I asked you remove this comment before. Only useful part is the
> > link. Everything else in it serves no purpose of any kind.
> > 
> > If you really want to comment in some way this is a version that
> > contains the useful information from above:
> > 
> > /* Even Log structures:
> >   * http://www.trustedcomputinggroup.org/tcg-efi-protocol-specification/
> >   */
> > 
> > Because of this you don't need to send anything. I'm just complaining
> > because it is still there :-)
> 
> Yeah..Sure.. Sorry, I guess I understood part of your previous comment. I
> have removed only the single line comments but kept this.
> 
> Thanks!!
> 
> Thanks & Regards,
>    -  Nayna
> 
> > 
> > > +
> > > +struct tcg_efi_specid_event_algs {
> > > +	u16 alg_id;
> > > +	u16 digest_size;
> > > +} __packed;
> > > +
> > > +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[TPM2_ACTIVE_PCR_BANKS];
> > > +	u8 vendor_info_size;
> > > +	u8 vendor_info[0];
> > > +} __packed;
> > > +
> > > +struct tcg_pcr_event {
> > > +	u32 pcr_idx;
> > > +	u32 event_type;
> > > +	u8 digest[20];
> > > +	u32 event_size;
> > > +	u8 event[0];
> > > +} __packed;
> > > +
> > > +struct tpm2_digest {
> > > +	u16 alg_id;
> > > +	u8 digest[SHA512_DIGEST_SIZE];
> > > +} __packed;
> > > +
> > > +struct tcg_event_field {
> > > +	u32 event_size;
> > > +	u8 event[0];
> > > +} __packed;
> > > +
> > > +struct tcg_pcr_event2 {
> > > +	u32 pcr_idx;
> > > +	u32 event_type;
> > > +	u32 count;
> > > +	struct tpm2_digest digests[TPM2_ACTIVE_PCR_BANKS];
> > > +	struct tcg_event_field event;
> > > +} __packed;
> > > +
> > > +extern const struct seq_operations tpm2_binary_b_measurements_seqops;
> > > +
> > >   #if defined(CONFIG_ACPI)
> > >   int tpm_read_log_acpi(struct tpm_chip *chip);
> > >   #else
> > > --
> > > 2.5.0
> > > 
> > 
> > I guess that this is OK but since the code isn't peer tested I cannot
> > apply.
> > 
> > /Jarkko
> >

You do not need to send a new patch set version as long as this
one gets peer tested. And it needs to be tested without hacks
like plumbing TCPA with TPM 2.0 in QEMU. OF code paths needs to
be peer tested to be more specific.

For me the code itself looks good but I simply cannot take it in
in the current situation.

/Jarkko

Powered by blists - more mailing lists