Commit fdc915f7 authored by James Bottomley's avatar James Bottomley Committed by Jarkko Sakkinen
Browse files

tpm: expose spaces via a device link /dev/tpmrm<n> 



Currently the tpm spaces are not exposed to userspace.  Make this
exposure via a separate device, which can now be opened multiple times
because each read/write transaction goes separately via the space.

Concurrency is protected by the chip->tpm_mutex for each read/write
transaction separately.  The TPM is cleared of all transient objects
by the time the mutex is dropped, so there should be no interference
between the kernel and userspace.

Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
Tested-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent ecb38e2f

drivers/char/tpm/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -3,7 +3,8 @@ 
#

obj-$(CONFIG_TCG_TPM) += tpm.o

tpm-y := tpm-interface.o tpm-dev.o tpm-sysfs.o tpm-chip.o tpm2-cmd.o \

	 tpm-dev-common.o tpm1_eventlog.o tpm2_eventlog.o tpm2-space.o

	 tpm-dev-common.o tpmrm-dev.o tpm1_eventlog.o tpm2_eventlog.o \

         tpm2-space.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

drivers/char/tpm/tpm-chip.c

+57 −1
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ DEFINE_IDR(dev_nums_idr); 
static DEFINE_MUTEX(idr_lock);



struct class *tpm_class;

struct class *tpmrm_class;

dev_t tpm_devt;



/**
@@ -132,6 +133,14 @@ static void tpm_dev_release(struct device *dev) 
	kfree(chip);

}



static void tpm_devs_release(struct device *dev)

{

	struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);



	/* release the master device reference */

	put_device(&chip->dev);

}



/**

 * tpm_chip_alloc() - allocate a new struct tpm_chip instance

 * @pdev: device to which the chip is associated
@@ -168,18 +177,35 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev, 
	chip->dev_num = rc;



	device_initialize(&chip->dev);

	device_initialize(&chip->devs);



	chip->dev.class = tpm_class;

	chip->dev.release = tpm_dev_release;

	chip->dev.parent = pdev;

	chip->dev.groups = chip->groups;



	chip->devs.parent = pdev;

	chip->devs.class = tpmrm_class;

	chip->devs.release = tpm_devs_release;

	/* get extra reference on main device to hold on

	 * behalf of devs.  This holds the chip structure

	 * while cdevs is in use.  The corresponding put

	 * is in the tpm_devs_release

	 */

	get_device(&chip->dev);



	if (chip->dev_num == 0)

		chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);

	else

		chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);



	chip->devs.devt =

		MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);



	rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);

	if (rc)

		goto out;

	rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num);

	if (rc)

		goto out;
@@ -187,8 +213,11 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev, 
		chip->flags |= TPM_CHIP_FLAG_VIRTUAL;



	cdev_init(&chip->cdev, &tpm_fops);

	cdev_init(&chip->cdevs, &tpmrm_fops);

	chip->cdev.owner = THIS_MODULE;

	chip->cdevs.owner = THIS_MODULE;

	chip->cdev.kobj.parent = &chip->dev.kobj;

	chip->cdevs.kobj.parent = &chip->devs.kobj;



	chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);

	if (!chip->work_space.context_buf) {
@@ -199,6 +228,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev, 
	return chip;



out:

	put_device(&chip->devs);

	put_device(&chip->dev);

	return ERR_PTR(rc);

}
@@ -243,7 +273,6 @@ static int tpm_add_char_device(struct tpm_chip *chip) 
			"unable to cdev_add() %s, major %d, minor %d, err=%d\n",

			dev_name(&chip->dev), MAJOR(chip->dev.devt),

			MINOR(chip->dev.devt), rc);



		return rc;

	}
@@ -258,6 +287,29 @@ static int tpm_add_char_device(struct tpm_chip *chip) 
		return rc;

	}



	if (chip->flags & TPM_CHIP_FLAG_TPM2)

		rc = cdev_add(&chip->cdevs, chip->devs.devt, 1);

	if (rc) {

		dev_err(&chip->dev,

			"unable to cdev_add() %s, major %d, minor %d, err=%d\n",

			dev_name(&chip->devs), MAJOR(chip->devs.devt),

			MINOR(chip->devs.devt), rc);

		tpm_del_char_device(chip, true);

		return rc;

	}



	if (chip->flags & TPM_CHIP_FLAG_TPM2)

		rc = device_add(&chip->devs);

	if (rc) {

		dev_err(&chip->dev,

			"unable to device_register() %s, major %d, minor %d, err=%d\n",

			dev_name(&chip->devs), MAJOR(chip->devs.devt),

			MINOR(chip->devs.devt), rc);

		cdev_del(&chip->cdevs);

		tpm_del_char_device(chip, true);

		return rc;

	}



	/* Make the chip available. */

	mutex_lock(&idr_lock);

	idr_replace(&dev_nums_idr, chip, chip->dev_num);
@@ -391,6 +443,10 @@ void tpm_chip_unregister(struct tpm_chip *chip) 
{

	tpm_del_legacy_sysfs(chip);

	tpm_bios_log_teardown(chip);

	if (chip->flags & TPM_CHIP_FLAG_TPM2) {

		cdev_del(&chip->cdevs);

		device_del(&chip->devs);

	}

	tpm_del_char_device(chip);

}

EXPORT_SYMBOL_GPL(tpm_chip_unregister);

drivers/char/tpm/tpm-interface.c

+11 −2
Original line number Diff line number Diff line
@@ -1262,9 +1262,17 @@ static int __init tpm_init(void) 
		return PTR_ERR(tpm_class);

	}



	rc = alloc_chrdev_region(&tpm_devt, 0, TPM_NUM_DEVICES, "tpm");

	tpmrm_class = class_create(THIS_MODULE, "tpmrm");

	if (IS_ERR(tpmrm_class)) {

		pr_err("couldn't create tpmrm class\n");

		class_destroy(tpm_class);

		return PTR_ERR(tpmrm_class);

	}



	rc = alloc_chrdev_region(&tpm_devt, 0, 2*TPM_NUM_DEVICES, "tpm");

	if (rc < 0) {

		pr_err("tpm: failed to allocate char dev region\n");

		class_destroy(tpmrm_class);

		class_destroy(tpm_class);

		return rc;

	}
@@ -1276,7 +1284,8 @@ static void __exit tpm_exit(void) 
{

	idr_destroy(&dev_nums_idr);

	class_destroy(tpm_class);

	unregister_chrdev_region(tpm_devt, TPM_NUM_DEVICES);

	class_destroy(tpmrm_class);

	unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES);

}



subsys_initcall(tpm_init);

drivers/char/tpm/tpm.h

+4 −0
Original line number Diff line number Diff line
@@ -182,7 +182,9 @@ struct tpm_chip_seqops { 


struct tpm_chip {

	struct device dev;

	struct device devs;

	struct cdev cdev;

	struct cdev cdevs;



	/* A driver callback under ops cannot be run unless ops_sem is held

	 * (sometimes implicitly, eg for the sysfs code). ops becomes null
@@ -510,8 +512,10 @@ static inline void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value) 
}



extern struct class *tpm_class;

extern struct class *tpmrm_class;

extern dev_t tpm_devt;

extern const struct file_operations tpm_fops;

extern const struct file_operations tpmrm_fops;

extern struct idr dev_nums_idr;



enum tpm_transmit_flags {

drivers/char/tpm/tpmrm-dev.c

0 → 100644
+65 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2017 James.Bottomley@HansenPartnership.com

 *

 * GPLv2

 */

#include <linux/slab.h>

#include "tpm-dev.h"



struct tpmrm_priv {

	struct file_priv priv;

	struct tpm_space space;

};



static int tpmrm_open(struct inode *inode, struct file *file)

{

	struct tpm_chip *chip;

	struct tpmrm_priv *priv;

	int rc;



	chip = container_of(inode->i_cdev, struct tpm_chip, cdevs);

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);

	if (priv == NULL)

		return -ENOMEM;



	rc = tpm2_init_space(&priv->space);

	if (rc) {

		kfree(priv);

		return -ENOMEM;

	}



	tpm_common_open(file, chip, &priv->priv);



	return 0;

}



static int tpmrm_release(struct inode *inode, struct file *file)

{

	struct file_priv *fpriv = file->private_data;

	struct tpmrm_priv *priv = container_of(fpriv, struct tpmrm_priv, priv);



	tpm_common_release(file, fpriv);

	tpm2_del_space(&priv->space);

	kfree(priv);



	return 0;

}



ssize_t tpmrm_write(struct file *file, const char __user *buf,

		   size_t size, loff_t *off)

{

	struct file_priv *fpriv = file->private_data;

	struct tpmrm_priv *priv = container_of(fpriv, struct tpmrm_priv, priv);



	return tpm_common_write(file, buf, size, off, &priv->space);

}



const struct file_operations tpmrm_fops = {

	.owner = THIS_MODULE,

	.llseek = no_llseek,

	.open = tpmrm_open,

	.read = tpm_common_read,

	.write = tpmrm_write,

	.release = tpmrm_release,

};

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