[RFC][Patch 6/6] integrity: TPM internal kernel interface

[Mimi Zohar <zohar@linux.vnet.ibm.com>]

Index: linux-2.6.21-rc3-mm2/drivers/char/tpm/tpm.c
===================================================================
--- linux-2.6.21-rc3-mm2.orig/drivers/char/tpm/tpm.c
+++ linux-2.6.21-rc3-mm2/drivers/char/tpm/tpm.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2004 IBM Corporation
+ * Copyright (C) 2004,2007 IBM Corporation
  *
  * Authors:
  * Leendert van Doorn <leendert@watson.ibm.com>
@@ -25,6 +25,12 @@
 
 #include <linux/poll.h>
 #include <linux/spinlock.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/crypto.h>
+#include <linux/fs.h>
+#include <asm/scatterlist.h>
 #include "tpm.h"
 
 enum tpm_const {
@@ -47,6 +53,8 @@ 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
@@ -363,7 +371,7 @@ EXPORT_SYMBOL_GPL(tpm_calc_ordinal_durat
 /*
  * Internal kernel interface to transmit TPM commands
  */
-static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
+ssize_t tpm_transmit(struct tpm_chip *chip, char *buf,
 			    size_t bufsiz)
 {
 	ssize_t rc;
@@ -422,6 +430,7 @@ out:
 	up(&chip->tpm_mutex);
 	return rc;
 }
+EXPORT_SYMBOL_GPL(tpm_transmit);
 
 #define TPM_DIGEST_SIZE 20
 #define TPM_ERROR_SIZE 10
@@ -665,6 +674,7 @@ ssize_t tpm_show_temp_deactivated(struct
 }
 EXPORT_SYMBOL_GPL(tpm_show_temp_deactivated);
 
+#define READ_PCR_RESULT_SIZE 30
 static const u8 pcrread[] = {
 	0, 193,			/* TPM_TAG_RQU_COMMAND */
 	0, 0, 0, 14,		/* length */
@@ -713,6 +723,93 @@ out:
 }
 EXPORT_SYMBOL_GPL(tpm_show_pcrs);
 
+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;
+}
+
+/*
+ * Return 0 on success.  On error pass along error code.
+ * chip_id Upper 2 bytes equal ANY, HW_ONLY or SW_ONLY
+ * Lower 2 bytes equal tpm idx # or AN&
+ * res_buf must fit a TPM_PCR (20 bytes) or NULL if you don't care
+ */
+int tpm_pcr_read( u32 chip_id, int pcr_idx, u8* res_buf, int res_buf_size )
+{
+        u8 data[READ_PCR_RESULT_SIZE];
+        int rc;
+        __be32 index;
+        int chip_num = chip_id & TPM_CHIP_NUM_MASK;
+        struct tpm_chip* chip;
+
+        if ( res_buf && res_buf_size < TPM_DIGEST_SIZE )
+                return -ENOSPC;
+
+        if ( (chip = tpm_chip_lookup( chip_num,
+                                chip_id >> TPM_CHIP_TYPE_SHIFT ) ) == NULL )
+                return -ENODEV;
+
+        memcpy(data, pcrread, sizeof(pcrread));
+        index = cpu_to_be32(pcr_idx);
+        memcpy(data + 10, &index, 4);
+        if ((rc = tpm_transmit(chip, data, sizeof(data))) > 0 )
+                rc = be32_to_cpu(*((u32*)(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 */
+};
+
+/*
+ * Return 0 on success.  On error pass along error code.
+ * chip_id Upper 2 bytes equal ANY, HW_ONLY or SW_ONLY
+ * Lower 2 bytes equal tpm idx # or ANY
+ */
+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;
+
+        if ( (chip = tpm_chip_lookup( chip_num,
+                        chip_id >> TPM_CHIP_TYPE_SHIFT )) == NULL )
+                return -ENODEV;
+
+        memcpy(data, pcrextend, sizeof(pcrextend));
+        index = cpu_to_be32(pcr_idx);
+        memcpy(data + 10, &index, 4);
+        memcpy( data + 14, hash, TPM_DIGEST_SIZE );
+        if ((rc = tpm_transmit(chip, data, sizeof(data))) > 0 )
+                rc = be32_to_cpu(*((u32*)(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 */
@@ -944,13 +1041,13 @@ int tpm_release(struct inode *inode, str
 
 	spin_lock(&driver_lock);
 	file->private_data = NULL;
+	spin_unlock(&driver_lock);
 	chip->num_opens--;
 	del_singleshot_timer_sync(&chip->user_read_timer);
 	flush_scheduled_work();
 	atomic_set(&chip->data_pending, 0);
 	put_device(chip->dev);
 	kfree(chip->data_buffer);
-	spin_unlock(&driver_lock);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(tpm_release);
Index: linux-2.6.21-rc3-mm2/drivers/char/tpm/tpm.h
===================================================================
--- linux-2.6.21-rc3-mm2.orig/drivers/char/tpm/tpm.h
+++ linux-2.6.21-rc3-mm2/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@watson.ibm.com>
@@ -25,6 +25,7 @@
 #include <linux/miscdevice.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
+#include <linux/tpm.h>
 
 enum tpm_timeout {
 	TPM_TIMEOUT = 5,	/* msecs */
Index: linux-2.6.21-rc3-mm2/include/linux/tpm.h
===================================================================
--- /dev/null
+++ linux-2.6.21-rc3-mm2/include/linux/tpm.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2004,2007 IBM Corporation
+ *
+ * Authors:
+ * Leendert van Doorn <leendert@watson.ibm.com>
+ * Dave Safford <safford@watson.ibm.com>
+ * Reiner Sailer <sailer@watson.ibm.com>
+ * Kylene Hall <kjhall@us.ibm.com>
+ *
+ * Maintained by: <tpmdd_devel@lists.sourceforge.net>
+ *
+ * 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 CONFIG_TCG_TPM 1
+#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,
+};
+
+
+#ifdef CONFIG_TCG_TPM
+extern int tpm_pcr_read(u32 chip_id, int pcr_idx, u8* res_buf, int res_buf_size);
+extern int tpm_pcr_extend(u32 chip_id, int pcr_idx, const u8* hash);
+#else
+static inline int tpm_pcr_read(u32 chip_id, int pcr_idx, u8* res_buf,
+				int res_buf_size)
+{
+	return -1;
+}
+
+static inline int tpm_pcr_extend(u32 chip_id, int pcr_idx, const u8* hash)
+{
+	return -1;
+}
+#endif
+#endif
+