[Patch 2/5]integrity: TPM internel kernel interface

From: Mimi Zohar
Date: Wed Jul 16 2008 - 16:06:35 EST

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Resubmitting integrity-tpm-internal-kernel-interface.patch, which
was previously Signed-off-by Kylene Hall.
Updated per feedback.

Adds the following support:
- make internal kernel interface to transmit TPM commands global
- adds reading a pcr value
- adds extending a pcr value
- adds lookup the tpm_chip for given chip number and type

Signed-off-by: Debora Velarde <debora@xxxxxxxxxxxxxxxxxx>

Reviewed-by: James Morris <jmorris@xxxxxxxxx>
---
Index: linux-2.6.26-git3/drivers/char/tpm/tpm.c
===================================================================
--- linux-2.6.26-git3.orig/drivers/char/tpm/tpm.c
+++ linux-2.6.26-git3/drivers/char/tpm/tpm.c
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2004 IBM Corporation
+ * Copyright (C) 2004,2007,2008 IBM Corporation
*
* Authors:
* Leendert van Doorn <leendert@xxxxxxxxxxxxxx>
@@ -29,6 +29,13 @@
#include <linux/spinlock.h>
#include <linux/smp_lock.h>

+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/crypto.h>
+#include <linux/fs.h>
+#include <linux/scatterlist.h>
+#include <asm/unaligned.h>
#include "tpm.h"

enum tpm_const {
@@ -51,6 +58,8 @@ enum tpm_duration {
static LIST_HEAD(tpm_chip_list);
static DEFINE_SPINLOCK(driver_lock);
static DECLARE_BITMAP(dev_mask, TPM_NUM_DEVICES);
+#define TPM_CHIP_NUM_MASK 0x0000ffff
+#define TPM_CHIP_TYPE_SHIFT 16

/*
* Array with one entry per ordinal defining the maximum amount
@@ -366,8 +375,7 @@ EXPORT_SYMBOL_GPL(tpm_calc_ordinal_durat
/*
* tpm_transmit - internal kernel interface to transmit TPM commands
*/
-static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
- size_t bufsiz)
+ssize_t tpm_transmit(struct tpm_chip *chip, char *buf, size_t bufsiz)
{
ssize_t rc;
u32 count, ordinal;
@@ -423,6 +431,7 @@ out:
mutex_unlock(&chip->tpm_mutex);
return rc;
}
+EXPORT_SYMBOL_GPL(tpm_transmit);

#define TPM_DIGEST_SIZE 20
#define TPM_ERROR_SIZE 10
@@ -728,6 +737,102 @@ out:
}
EXPORT_SYMBOL_GPL(tpm_show_pcrs);

+/*
+ * tpm_chip_lookup - return tpm_chip for given chip number and type
+ */
+static struct tpm_chip *tpm_chip_lookup(int chip_num, int chip_typ)
+{
+ struct tpm_chip *pos;
+
+ spin_lock(&driver_lock);
+ list_for_each_entry(pos, &tpm_chip_list, list) {
+ if ((chip_num == TPM_ANY_NUM || pos->dev_num == chip_num)
+ && (chip_typ == TPM_ANY_TYPE)) {
+ spin_unlock(&driver_lock);
+ return pos;
+ }
+ }
+
+ spin_unlock(&driver_lock);
+ return NULL;
+}
+
+/**
+ * tpm_pcr_read - read a pcr value
+ * @chip_id: tpm chip identifier
+ * Upper 2 bytes: ANY, HW_ONLY or SW_ONLY
+ * Lower 2 bytes: tpm idx # or AN&
+ * @pcr_idx: pcr idx to retrieve
+ * @res_buf: TPM_PCR value
+ * size of res_buf is 20 bytes (or NULL if you don't care)
+ */
+int tpm_pcr_read(u32 chip_id, int pcr_idx, u8 *res_buf)
+{
+ u8 data[READ_PCR_RESULT_SIZE];
+ int rc;
+ __be32 index;
+ int chip_num = chip_id & TPM_CHIP_NUM_MASK;
+ struct tpm_chip *chip;
+
+ chip = tpm_chip_lookup(chip_num, chip_id >> TPM_CHIP_TYPE_SHIFT);
+ if (chip == NULL)
+ return -ENODEV;
+ BUILD_BUG_ON(sizeof(pcrread) > READ_PCR_RESULT_SIZE);
+ memcpy(data, pcrread, sizeof(pcrread));
+ index = cpu_to_be32(pcr_idx);
+ memcpy(data + 10, &index, 4);
+ rc = tpm_transmit(chip, data, sizeof(data));
+ if (rc > 0)
+ rc = get_unaligned_be32((__be32 *) (data + 6));
+
+ if (rc == 0 && res_buf)
+ memcpy(res_buf, data + 10, TPM_DIGEST_SIZE);
+
+ return rc;
+
+}
+EXPORT_SYMBOL_GPL(tpm_pcr_read);
+
+#define EXTEND_PCR_SIZE 34
+static const u8 pcrextend[] = {
+ 0, 193, /* TPM_TAG_RQU_COMMAND */
+ 0, 0, 0, 34, /* length */
+ 0, 0, 0, 20, /* TPM_ORD_Extend */
+ 0, 0, 0, 0 /* PCR index */
+};
+
+/**
+ * tpm_pcr_extend - extend pcr value with hash
+ * @chip_id: tpm chip identifier
+ * Upper 2 bytes: ANY, HW_ONLY or SW_ONLY
+ * Lower 2 bytes: tpm idx # or AN&
+ * @pcr_idx: pcr idx to extend
+ * @hash: hash value used to extend pcr value
+ */
+int tpm_pcr_extend(u32 chip_id, int pcr_idx, const u8 *hash)
+{
+ u8 data[EXTEND_PCR_SIZE];
+ int rc;
+ __be32 index;
+ int chip_num = chip_id & TPM_CHIP_NUM_MASK;
+ struct tpm_chip *chip;
+
+ chip = tpm_chip_lookup(chip_num, chip_id >> TPM_CHIP_TYPE_SHIFT);
+ if (chip == NULL)
+ return -ENODEV;
+
+ BUILD_BUG_ON(sizeof(pcrextend) > EXTEND_PCR_SIZE);
+ memcpy(data, pcrextend, sizeof(pcrextend));
+ index = cpu_to_be32(pcr_idx);
+ memcpy(data + 10, &index, 4);
+ memcpy(data + 14, hash, TPM_DIGEST_SIZE);
+ rc = tpm_transmit(chip, data, sizeof(data));
+ if (rc > 0)
+ rc = get_unaligned_be32((__be32 *) (data + 6));
+ return rc;
+}
+EXPORT_SYMBOL_GPL(tpm_pcr_extend);
+
#define READ_PUBEK_RESULT_SIZE 314
static const u8 readpubek[] = {
0, 193, /* TPM_TAG_RQU_COMMAND */
Index: linux-2.6.26-git3/drivers/char/tpm/tpm.h
===================================================================
--- linux-2.6.26-git3.orig/drivers/char/tpm/tpm.h
+++ linux-2.6.26-git3/drivers/char/tpm/tpm.h
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2004 IBM Corporation
+ * Copyright (C) 2004, 2007 IBM Corporation
*
* Authors:
* Leendert van Doorn <leendert@xxxxxxxxxxxxxx>
@@ -26,6 +26,7 @@
#include <linux/miscdevice.h>
#include <linux/platform_device.h>
#include <linux/io.h>
+#include <linux/tpm.h>

enum tpm_timeout {
TPM_TIMEOUT = 5, /* msecs */
@@ -128,6 +129,7 @@ extern void tpm_get_timeouts(struct tpm_
extern void tpm_gen_interrupt(struct tpm_chip *);
extern void tpm_continue_selftest(struct tpm_chip *);
extern unsigned long tpm_calc_ordinal_duration(struct tpm_chip *, u32);
+ssize_t tpm_transmit(struct tpm_chip *chip, char *buf, size_t bufsiz);
extern struct tpm_chip* tpm_register_hardware(struct device *,
const struct tpm_vendor_specific *);
extern int tpm_open(struct inode *, struct file *);
Index: linux-2.6.26-git3/include/linux/tpm.h
===================================================================
--- /dev/null
+++ linux-2.6.26-git3/include/linux/tpm.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2004,2007 IBM Corporation
+ *
+ * Authors:
+ * Leendert van Doorn <leendert@xxxxxxxxxxxxxx>
+ * Dave Safford <safford@xxxxxxxxxxxxxx>
+ * Reiner Sailer <sailer@xxxxxxxxxxxxxx>
+ * Kylene Hall <kjhall@xxxxxxxxxx>
+ * Debora Velarde <dvelarde@xxxxxxxxxx>
+ *
+ * Maintained by: <tpmdd_devel@xxxxxxxxxxxxxxxxxxxxx>
+ *
+ * Device driver for TCG/TCPA TPM (trusted platform module).
+ * Specifications at www.trustedcomputinggroup.org
+ *
+ * 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, version 2 of the
+ * License.
+ *
+ */
+#ifndef __LINUX_TPM_H__
+#define __LINUX_TPM_H__
+
+#define PCI_DEVICE_ID_AMD_8111_LPC 0x7468
+
+/*
+ * Chip type is one of these values in the upper two bytes of chip_id
+ */
+enum tpm_chip_type {
+ TPM_HW_TYPE = 0x0,
+ TPM_SW_TYPE = 0x1,
+ TPM_ANY_TYPE = 0xFFFF,
+};
+
+/*
+ * Chip num is this value or a valid tpm idx in lower two bytes of chip_id
+ */
+enum tpm_chip_num {
+ TPM_ANY_NUM = 0xFFFF,
+};
+
+
+#if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
+
+extern int tpm_pcr_read(u32 chip_id, int pcr_idx, u8 *res_buf);
+extern int tpm_pcr_extend(u32 chip_id, int pcr_idx, const u8 *hash);
+#endif
+#endif

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Next message: Mimi Zohar: "[Patch 5/5]integrity: IMA as an integrity service provider"
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