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: James Bottomley <James.Bottomley@HansenPartnership.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
This commit is contained in:
James Bottomley 2017-01-03 09:07:32 -08:00 committed by Jarkko Sakkinen
parent ecb38e2f52
commit fdc915f7f7
5 changed files with 139 additions and 4 deletions

View file

@ -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

View file

@ -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);

View file

@ -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);

View file

@ -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 {

View file

@ -0,0 +1,65 @@
/*
* 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,
};