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path: root/drivers/char/tpm/tpm_vtpm_proxy.c
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-rw-r--r--drivers/char/tpm/tpm_vtpm_proxy.c717
1 files changed, 717 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
new file mode 100644
index 000000000..30e953988
--- /dev/null
+++ b/drivers/char/tpm/tpm_vtpm_proxy.c
@@ -0,0 +1,717 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015, 2016 IBM Corporation
+ * Copyright (C) 2016 Intel Corporation
+ *
+ * Author: Stefan Berger <stefanb@us.ibm.com>
+ *
+ * Maintained by: <tpmdd-devel@lists.sourceforge.net>
+ *
+ * Device driver for vTPM (vTPM proxy driver)
+ */
+
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+#include <linux/miscdevice.h>
+#include <linux/vtpm_proxy.h>
+#include <linux/file.h>
+#include <linux/anon_inodes.h>
+#include <linux/poll.h>
+#include <linux/compat.h>
+
+#include "tpm.h"
+
+#define VTPM_PROXY_REQ_COMPLETE_FLAG BIT(0)
+
+struct proxy_dev {
+ struct tpm_chip *chip;
+
+ u32 flags; /* public API flags */
+
+ wait_queue_head_t wq;
+
+ struct mutex buf_lock; /* protect buffer and flags */
+
+ long state; /* internal state */
+#define STATE_OPENED_FLAG BIT(0)
+#define STATE_WAIT_RESPONSE_FLAG BIT(1) /* waiting for emulator response */
+#define STATE_REGISTERED_FLAG BIT(2)
+#define STATE_DRIVER_COMMAND BIT(3) /* sending a driver specific command */
+
+ size_t req_len; /* length of queued TPM request */
+ size_t resp_len; /* length of queued TPM response */
+ u8 buffer[TPM_BUFSIZE]; /* request/response buffer */
+
+ struct work_struct work; /* task that retrieves TPM timeouts */
+};
+
+/* all supported flags */
+#define VTPM_PROXY_FLAGS_ALL (VTPM_PROXY_FLAG_TPM2)
+
+static struct workqueue_struct *workqueue;
+
+static void vtpm_proxy_delete_device(struct proxy_dev *proxy_dev);
+
+/*
+ * Functions related to 'server side'
+ */
+
+/**
+ * vtpm_proxy_fops_read - Read TPM commands on 'server side'
+ *
+ * @filp: file pointer
+ * @buf: read buffer
+ * @count: number of bytes to read
+ * @off: offset
+ *
+ * Return:
+ * Number of bytes read or negative error code
+ */
+static ssize_t vtpm_proxy_fops_read(struct file *filp, char __user *buf,
+ size_t count, loff_t *off)
+{
+ struct proxy_dev *proxy_dev = filp->private_data;
+ size_t len;
+ int sig, rc;
+
+ sig = wait_event_interruptible(proxy_dev->wq,
+ proxy_dev->req_len != 0 ||
+ !(proxy_dev->state & STATE_OPENED_FLAG));
+ if (sig)
+ return -EINTR;
+
+ mutex_lock(&proxy_dev->buf_lock);
+
+ if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
+ mutex_unlock(&proxy_dev->buf_lock);
+ return -EPIPE;
+ }
+
+ len = proxy_dev->req_len;
+
+ if (count < len || len > sizeof(proxy_dev->buffer)) {
+ mutex_unlock(&proxy_dev->buf_lock);
+ pr_debug("Invalid size in recv: count=%zd, req_len=%zd\n",
+ count, len);
+ return -EIO;
+ }
+
+ rc = copy_to_user(buf, proxy_dev->buffer, len);
+ memset(proxy_dev->buffer, 0, len);
+ proxy_dev->req_len = 0;
+
+ if (!rc)
+ proxy_dev->state |= STATE_WAIT_RESPONSE_FLAG;
+
+ mutex_unlock(&proxy_dev->buf_lock);
+
+ if (rc)
+ return -EFAULT;
+
+ return len;
+}
+
+/**
+ * vtpm_proxy_fops_write - Write TPM responses on 'server side'
+ *
+ * @filp: file pointer
+ * @buf: write buffer
+ * @count: number of bytes to write
+ * @off: offset
+ *
+ * Return:
+ * Number of bytes read or negative error value
+ */
+static ssize_t vtpm_proxy_fops_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *off)
+{
+ struct proxy_dev *proxy_dev = filp->private_data;
+
+ mutex_lock(&proxy_dev->buf_lock);
+
+ if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
+ mutex_unlock(&proxy_dev->buf_lock);
+ return -EPIPE;
+ }
+
+ if (count > sizeof(proxy_dev->buffer) ||
+ !(proxy_dev->state & STATE_WAIT_RESPONSE_FLAG)) {
+ mutex_unlock(&proxy_dev->buf_lock);
+ return -EIO;
+ }
+
+ proxy_dev->state &= ~STATE_WAIT_RESPONSE_FLAG;
+
+ proxy_dev->req_len = 0;
+
+ if (copy_from_user(proxy_dev->buffer, buf, count)) {
+ mutex_unlock(&proxy_dev->buf_lock);
+ return -EFAULT;
+ }
+
+ proxy_dev->resp_len = count;
+
+ mutex_unlock(&proxy_dev->buf_lock);
+
+ wake_up_interruptible(&proxy_dev->wq);
+
+ return count;
+}
+
+/*
+ * vtpm_proxy_fops_poll - Poll status on 'server side'
+ *
+ * @filp: file pointer
+ * @wait: poll table
+ *
+ * Return: Poll flags
+ */
+static __poll_t vtpm_proxy_fops_poll(struct file *filp, poll_table *wait)
+{
+ struct proxy_dev *proxy_dev = filp->private_data;
+ __poll_t ret;
+
+ poll_wait(filp, &proxy_dev->wq, wait);
+
+ ret = EPOLLOUT;
+
+ mutex_lock(&proxy_dev->buf_lock);
+
+ if (proxy_dev->req_len)
+ ret |= EPOLLIN | EPOLLRDNORM;
+
+ if (!(proxy_dev->state & STATE_OPENED_FLAG))
+ ret |= EPOLLHUP;
+
+ mutex_unlock(&proxy_dev->buf_lock);
+
+ return ret;
+}
+
+/*
+ * vtpm_proxy_fops_open - Open vTPM device on 'server side'
+ *
+ * @filp: file pointer
+ *
+ * Called when setting up the anonymous file descriptor
+ */
+static void vtpm_proxy_fops_open(struct file *filp)
+{
+ struct proxy_dev *proxy_dev = filp->private_data;
+
+ proxy_dev->state |= STATE_OPENED_FLAG;
+}
+
+/**
+ * vtpm_proxy_fops_undo_open - counter-part to vtpm_fops_open
+ * Call to undo vtpm_proxy_fops_open
+ *
+ *@proxy_dev: tpm proxy device
+ */
+static void vtpm_proxy_fops_undo_open(struct proxy_dev *proxy_dev)
+{
+ mutex_lock(&proxy_dev->buf_lock);
+
+ proxy_dev->state &= ~STATE_OPENED_FLAG;
+
+ mutex_unlock(&proxy_dev->buf_lock);
+
+ /* no more TPM responses -- wake up anyone waiting for them */
+ wake_up_interruptible(&proxy_dev->wq);
+}
+
+/*
+ * vtpm_proxy_fops_release - Close 'server side'
+ *
+ * @inode: inode
+ * @filp: file pointer
+ * Return:
+ * Always returns 0.
+ */
+static int vtpm_proxy_fops_release(struct inode *inode, struct file *filp)
+{
+ struct proxy_dev *proxy_dev = filp->private_data;
+
+ filp->private_data = NULL;
+
+ vtpm_proxy_delete_device(proxy_dev);
+
+ return 0;
+}
+
+static const struct file_operations vtpm_proxy_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .read = vtpm_proxy_fops_read,
+ .write = vtpm_proxy_fops_write,
+ .poll = vtpm_proxy_fops_poll,
+ .release = vtpm_proxy_fops_release,
+};
+
+/*
+ * Functions invoked by the core TPM driver to send TPM commands to
+ * 'server side' and receive responses from there.
+ */
+
+/*
+ * Called when core TPM driver reads TPM responses from 'server side'
+ *
+ * @chip: tpm chip to use
+ * @buf: receive buffer
+ * @count: bytes to read
+ * Return:
+ * Number of TPM response bytes read, negative error value otherwise
+ */
+static int vtpm_proxy_tpm_op_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+ struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
+ size_t len;
+
+ /* process gone ? */
+ mutex_lock(&proxy_dev->buf_lock);
+
+ if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
+ mutex_unlock(&proxy_dev->buf_lock);
+ return -EPIPE;
+ }
+
+ len = proxy_dev->resp_len;
+ if (count < len) {
+ dev_err(&chip->dev,
+ "Invalid size in recv: count=%zd, resp_len=%zd\n",
+ count, len);
+ len = -EIO;
+ goto out;
+ }
+
+ memcpy(buf, proxy_dev->buffer, len);
+ proxy_dev->resp_len = 0;
+
+out:
+ mutex_unlock(&proxy_dev->buf_lock);
+
+ return len;
+}
+
+static int vtpm_proxy_is_driver_command(struct tpm_chip *chip,
+ u8 *buf, size_t count)
+{
+ struct tpm_header *hdr = (struct tpm_header *)buf;
+
+ if (count < sizeof(struct tpm_header))
+ return 0;
+
+ if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+ switch (be32_to_cpu(hdr->ordinal)) {
+ case TPM2_CC_SET_LOCALITY:
+ return 1;
+ }
+ } else {
+ switch (be32_to_cpu(hdr->ordinal)) {
+ case TPM_ORD_SET_LOCALITY:
+ return 1;
+ }
+ }
+ return 0;
+}
+
+/*
+ * Called when core TPM driver forwards TPM requests to 'server side'.
+ *
+ * @chip: tpm chip to use
+ * @buf: send buffer
+ * @count: bytes to send
+ *
+ * Return:
+ * 0 in case of success, negative error value otherwise.
+ */
+static int vtpm_proxy_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+ struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
+
+ if (count > sizeof(proxy_dev->buffer)) {
+ dev_err(&chip->dev,
+ "Invalid size in send: count=%zd, buffer size=%zd\n",
+ count, sizeof(proxy_dev->buffer));
+ return -EIO;
+ }
+
+ if (!(proxy_dev->state & STATE_DRIVER_COMMAND) &&
+ vtpm_proxy_is_driver_command(chip, buf, count))
+ return -EFAULT;
+
+ mutex_lock(&proxy_dev->buf_lock);
+
+ if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
+ mutex_unlock(&proxy_dev->buf_lock);
+ return -EPIPE;
+ }
+
+ proxy_dev->resp_len = 0;
+
+ proxy_dev->req_len = count;
+ memcpy(proxy_dev->buffer, buf, count);
+
+ proxy_dev->state &= ~STATE_WAIT_RESPONSE_FLAG;
+
+ mutex_unlock(&proxy_dev->buf_lock);
+
+ wake_up_interruptible(&proxy_dev->wq);
+
+ return 0;
+}
+
+static void vtpm_proxy_tpm_op_cancel(struct tpm_chip *chip)
+{
+ /* not supported */
+}
+
+static u8 vtpm_proxy_tpm_op_status(struct tpm_chip *chip)
+{
+ struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
+
+ if (proxy_dev->resp_len)
+ return VTPM_PROXY_REQ_COMPLETE_FLAG;
+
+ return 0;
+}
+
+static bool vtpm_proxy_tpm_req_canceled(struct tpm_chip *chip, u8 status)
+{
+ struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
+ bool ret;
+
+ mutex_lock(&proxy_dev->buf_lock);
+
+ ret = !(proxy_dev->state & STATE_OPENED_FLAG);
+
+ mutex_unlock(&proxy_dev->buf_lock);
+
+ return ret;
+}
+
+static int vtpm_proxy_request_locality(struct tpm_chip *chip, int locality)
+{
+ struct tpm_buf buf;
+ int rc;
+ const struct tpm_header *header;
+ struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
+
+ if (chip->flags & TPM_CHIP_FLAG_TPM2)
+ rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS,
+ TPM2_CC_SET_LOCALITY);
+ else
+ rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND,
+ TPM_ORD_SET_LOCALITY);
+ if (rc)
+ return rc;
+ tpm_buf_append_u8(&buf, locality);
+
+ proxy_dev->state |= STATE_DRIVER_COMMAND;
+
+ rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to set locality");
+
+ proxy_dev->state &= ~STATE_DRIVER_COMMAND;
+
+ if (rc < 0) {
+ locality = rc;
+ goto out;
+ }
+
+ header = (const struct tpm_header *)buf.data;
+ rc = be32_to_cpu(header->return_code);
+ if (rc)
+ locality = -1;
+
+out:
+ tpm_buf_destroy(&buf);
+
+ return locality;
+}
+
+static const struct tpm_class_ops vtpm_proxy_tpm_ops = {
+ .flags = TPM_OPS_AUTO_STARTUP,
+ .recv = vtpm_proxy_tpm_op_recv,
+ .send = vtpm_proxy_tpm_op_send,
+ .cancel = vtpm_proxy_tpm_op_cancel,
+ .status = vtpm_proxy_tpm_op_status,
+ .req_complete_mask = VTPM_PROXY_REQ_COMPLETE_FLAG,
+ .req_complete_val = VTPM_PROXY_REQ_COMPLETE_FLAG,
+ .req_canceled = vtpm_proxy_tpm_req_canceled,
+ .request_locality = vtpm_proxy_request_locality,
+};
+
+/*
+ * Code related to the startup of the TPM 2 and startup of TPM 1.2 +
+ * retrieval of timeouts and durations.
+ */
+
+static void vtpm_proxy_work(struct work_struct *work)
+{
+ struct proxy_dev *proxy_dev = container_of(work, struct proxy_dev,
+ work);
+ int rc;
+
+ rc = tpm_chip_register(proxy_dev->chip);
+ if (rc)
+ vtpm_proxy_fops_undo_open(proxy_dev);
+ else
+ proxy_dev->state |= STATE_REGISTERED_FLAG;
+}
+
+/*
+ * vtpm_proxy_work_stop: make sure the work has finished
+ *
+ * This function is useful when user space closed the fd
+ * while the driver still determines timeouts.
+ */
+static void vtpm_proxy_work_stop(struct proxy_dev *proxy_dev)
+{
+ vtpm_proxy_fops_undo_open(proxy_dev);
+ flush_work(&proxy_dev->work);
+}
+
+/*
+ * vtpm_proxy_work_start: Schedule the work for TPM 1.2 & 2 initialization
+ */
+static inline void vtpm_proxy_work_start(struct proxy_dev *proxy_dev)
+{
+ queue_work(workqueue, &proxy_dev->work);
+}
+
+/*
+ * Code related to creation and deletion of device pairs
+ */
+static struct proxy_dev *vtpm_proxy_create_proxy_dev(void)
+{
+ struct proxy_dev *proxy_dev;
+ struct tpm_chip *chip;
+ int err;
+
+ proxy_dev = kzalloc(sizeof(*proxy_dev), GFP_KERNEL);
+ if (proxy_dev == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ init_waitqueue_head(&proxy_dev->wq);
+ mutex_init(&proxy_dev->buf_lock);
+ INIT_WORK(&proxy_dev->work, vtpm_proxy_work);
+
+ chip = tpm_chip_alloc(NULL, &vtpm_proxy_tpm_ops);
+ if (IS_ERR(chip)) {
+ err = PTR_ERR(chip);
+ goto err_proxy_dev_free;
+ }
+ dev_set_drvdata(&chip->dev, proxy_dev);
+
+ proxy_dev->chip = chip;
+
+ return proxy_dev;
+
+err_proxy_dev_free:
+ kfree(proxy_dev);
+
+ return ERR_PTR(err);
+}
+
+/*
+ * Undo what has been done in vtpm_create_proxy_dev
+ */
+static inline void vtpm_proxy_delete_proxy_dev(struct proxy_dev *proxy_dev)
+{
+ put_device(&proxy_dev->chip->dev); /* frees chip */
+ kfree(proxy_dev);
+}
+
+/*
+ * Create a /dev/tpm%d and 'server side' file descriptor pair
+ *
+ * Return:
+ * Returns file pointer on success, an error value otherwise
+ */
+static struct file *vtpm_proxy_create_device(
+ struct vtpm_proxy_new_dev *vtpm_new_dev)
+{
+ struct proxy_dev *proxy_dev;
+ int rc, fd;
+ struct file *file;
+
+ if (vtpm_new_dev->flags & ~VTPM_PROXY_FLAGS_ALL)
+ return ERR_PTR(-EOPNOTSUPP);
+
+ proxy_dev = vtpm_proxy_create_proxy_dev();
+ if (IS_ERR(proxy_dev))
+ return ERR_CAST(proxy_dev);
+
+ proxy_dev->flags = vtpm_new_dev->flags;
+
+ /* setup an anonymous file for the server-side */
+ fd = get_unused_fd_flags(O_RDWR);
+ if (fd < 0) {
+ rc = fd;
+ goto err_delete_proxy_dev;
+ }
+
+ file = anon_inode_getfile("[vtpms]", &vtpm_proxy_fops, proxy_dev,
+ O_RDWR);
+ if (IS_ERR(file)) {
+ rc = PTR_ERR(file);
+ goto err_put_unused_fd;
+ }
+
+ /* from now on we can unwind with put_unused_fd() + fput() */
+ /* simulate an open() on the server side */
+ vtpm_proxy_fops_open(file);
+
+ if (proxy_dev->flags & VTPM_PROXY_FLAG_TPM2)
+ proxy_dev->chip->flags |= TPM_CHIP_FLAG_TPM2;
+
+ vtpm_proxy_work_start(proxy_dev);
+
+ vtpm_new_dev->fd = fd;
+ vtpm_new_dev->major = MAJOR(proxy_dev->chip->dev.devt);
+ vtpm_new_dev->minor = MINOR(proxy_dev->chip->dev.devt);
+ vtpm_new_dev->tpm_num = proxy_dev->chip->dev_num;
+
+ return file;
+
+err_put_unused_fd:
+ put_unused_fd(fd);
+
+err_delete_proxy_dev:
+ vtpm_proxy_delete_proxy_dev(proxy_dev);
+
+ return ERR_PTR(rc);
+}
+
+/*
+ * Counter part to vtpm_create_device.
+ */
+static void vtpm_proxy_delete_device(struct proxy_dev *proxy_dev)
+{
+ vtpm_proxy_work_stop(proxy_dev);
+
+ /*
+ * A client may hold the 'ops' lock, so let it know that the server
+ * side shuts down before we try to grab the 'ops' lock when
+ * unregistering the chip.
+ */
+ vtpm_proxy_fops_undo_open(proxy_dev);
+
+ if (proxy_dev->state & STATE_REGISTERED_FLAG)
+ tpm_chip_unregister(proxy_dev->chip);
+
+ vtpm_proxy_delete_proxy_dev(proxy_dev);
+}
+
+/*
+ * Code related to the control device /dev/vtpmx
+ */
+
+/**
+ * vtpmx_ioc_new_dev - handler for the %VTPM_PROXY_IOC_NEW_DEV ioctl
+ * @file: /dev/vtpmx
+ * @ioctl: the ioctl number
+ * @arg: pointer to the struct vtpmx_proxy_new_dev
+ *
+ * Creates an anonymous file that is used by the process acting as a TPM to
+ * communicate with the client processes. The function will also add a new TPM
+ * device through which data is proxied to this TPM acting process. The caller
+ * will be provided with a file descriptor to communicate with the clients and
+ * major and minor numbers for the TPM device.
+ */
+static long vtpmx_ioc_new_dev(struct file *file, unsigned int ioctl,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ struct vtpm_proxy_new_dev __user *vtpm_new_dev_p;
+ struct vtpm_proxy_new_dev vtpm_new_dev;
+ struct file *vtpm_file;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ vtpm_new_dev_p = argp;
+
+ if (copy_from_user(&vtpm_new_dev, vtpm_new_dev_p,
+ sizeof(vtpm_new_dev)))
+ return -EFAULT;
+
+ vtpm_file = vtpm_proxy_create_device(&vtpm_new_dev);
+ if (IS_ERR(vtpm_file))
+ return PTR_ERR(vtpm_file);
+
+ if (copy_to_user(vtpm_new_dev_p, &vtpm_new_dev,
+ sizeof(vtpm_new_dev))) {
+ put_unused_fd(vtpm_new_dev.fd);
+ fput(vtpm_file);
+ return -EFAULT;
+ }
+
+ fd_install(vtpm_new_dev.fd, vtpm_file);
+ return 0;
+}
+
+/*
+ * vtpmx_fops_ioctl: ioctl on /dev/vtpmx
+ *
+ * Return:
+ * Returns 0 on success, a negative error code otherwise.
+ */
+static long vtpmx_fops_ioctl(struct file *f, unsigned int ioctl,
+ unsigned long arg)
+{
+ switch (ioctl) {
+ case VTPM_PROXY_IOC_NEW_DEV:
+ return vtpmx_ioc_new_dev(f, ioctl, arg);
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+
+static const struct file_operations vtpmx_fops = {
+ .owner = THIS_MODULE,
+ .unlocked_ioctl = vtpmx_fops_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+ .llseek = noop_llseek,
+};
+
+static struct miscdevice vtpmx_miscdev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "vtpmx",
+ .fops = &vtpmx_fops,
+};
+
+static int __init vtpm_module_init(void)
+{
+ int rc;
+
+ workqueue = create_workqueue("tpm-vtpm");
+ if (!workqueue) {
+ pr_err("couldn't create workqueue\n");
+ return -ENOMEM;
+ }
+
+ rc = misc_register(&vtpmx_miscdev);
+ if (rc) {
+ pr_err("couldn't create vtpmx device\n");
+ destroy_workqueue(workqueue);
+ }
+
+ return rc;
+}
+
+static void __exit vtpm_module_exit(void)
+{
+ destroy_workqueue(workqueue);
+ misc_deregister(&vtpmx_miscdev);
+}
+
+module_init(vtpm_module_init);
+module_exit(vtpm_module_exit);
+
+MODULE_AUTHOR("Stefan Berger (stefanb@us.ibm.com)");
+MODULE_DESCRIPTION("vTPM Driver");
+MODULE_VERSION("0.1");
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-12 23:49:36 +0000