From fdc915f7f71939ad5a3dda3389b8d2d7a7c5ee66 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Tue, 3 Jan 2017 09:07:32 -0800 Subject: [PATCH] tpm: expose spaces via a device link /dev/tpmrm 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 Tested-by: Jarkko Sakkinen Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/Makefile | 3 +- drivers/char/tpm/tpm-chip.c | 58 +++++++++++++++++++++++++++- drivers/char/tpm/tpm-interface.c | 13 ++++++- drivers/char/tpm/tpm.h | 4 ++ drivers/char/tpm/tpmrm-dev.c | 65 ++++++++++++++++++++++++++++++++ 5 files changed, 139 insertions(+), 4 deletions(-) create mode 100644 drivers/char/tpm/tpmrm-dev.c diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile index 10e5827445fc..23681f01f95a 100644 --- a/drivers/char/tpm/Makefile +++ b/drivers/char/tpm/Makefile @@ -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 diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 993b9ae42876..187ec04ce9c3 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -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); diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index d09cf26365c3..16abbf9cb53a 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -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); diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index 023fc02ad0f6..16dd207a4542 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -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 { diff --git a/drivers/char/tpm/tpmrm-dev.c b/drivers/char/tpm/tpmrm-dev.c new file mode 100644 index 000000000000..630bddce65a8 --- /dev/null +++ b/drivers/char/tpm/tpmrm-dev.c @@ -0,0 +1,65 @@ +/* + * Copyright (C) 2017 James.Bottomley@HansenPartnership.com + * + * GPLv2 + */ +#include +#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, +}; + -- 2.45.2