2 * Copyright (C) 2015, 2016 IBM Corporation
3 * Copyright (C) 2016 Intel Corporation
5 * Author: Stefan Berger <stefanb@us.ibm.com>
7 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
9 * Device driver for vTPM (vTPM proxy driver)
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License as
13 * published by the Free Software Foundation, version 2 of the
18 #include <linux/types.h>
19 #include <linux/spinlock.h>
20 #include <linux/uaccess.h>
21 #include <linux/wait.h>
22 #include <linux/miscdevice.h>
23 #include <linux/vtpm_proxy.h>
24 #include <linux/file.h>
25 #include <linux/anon_inodes.h>
26 #include <linux/poll.h>
27 #include <linux/compat.h>
31 #define VTPM_PROXY_REQ_COMPLETE_FLAG BIT(0)
34 struct tpm_chip *chip;
36 u32 flags; /* public API flags */
40 struct mutex buf_lock; /* protect buffer and flags */
42 long state; /* internal state */
43 #define STATE_OPENED_FLAG BIT(0)
44 #define STATE_WAIT_RESPONSE_FLAG BIT(1) /* waiting for emulator response */
45 #define STATE_REGISTERED_FLAG BIT(2)
47 size_t req_len; /* length of queued TPM request */
48 size_t resp_len; /* length of queued TPM response */
49 u8 buffer[TPM_BUFSIZE]; /* request/response buffer */
51 struct work_struct work; /* task that retrieves TPM timeouts */
54 /* all supported flags */
55 #define VTPM_PROXY_FLAGS_ALL (VTPM_PROXY_FLAG_TPM2)
57 static struct workqueue_struct *workqueue;
59 static void vtpm_proxy_delete_device(struct proxy_dev *proxy_dev);
62 * Functions related to 'server side'
66 * vtpm_proxy_fops_read - Read TPM commands on 'server side'
70 * @count: number of bytes to read
74 * Number of bytes read or negative error code
76 static ssize_t vtpm_proxy_fops_read(struct file *filp, char __user *buf,
77 size_t count, loff_t *off)
79 struct proxy_dev *proxy_dev = filp->private_data;
83 sig = wait_event_interruptible(proxy_dev->wq,
84 proxy_dev->req_len != 0 ||
85 !(proxy_dev->state & STATE_OPENED_FLAG));
89 mutex_lock(&proxy_dev->buf_lock);
91 if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
92 mutex_unlock(&proxy_dev->buf_lock);
96 len = proxy_dev->req_len;
99 mutex_unlock(&proxy_dev->buf_lock);
100 pr_debug("Invalid size in recv: count=%zd, req_len=%zd\n",
105 rc = copy_to_user(buf, proxy_dev->buffer, len);
106 memset(proxy_dev->buffer, 0, len);
107 proxy_dev->req_len = 0;
110 proxy_dev->state |= STATE_WAIT_RESPONSE_FLAG;
112 mutex_unlock(&proxy_dev->buf_lock);
121 * vtpm_proxy_fops_write - Write TPM responses on 'server side'
123 * @filp: file pointer
125 * @count: number of bytes to write
129 * Number of bytes read or negative error value
131 static ssize_t vtpm_proxy_fops_write(struct file *filp, const char __user *buf,
132 size_t count, loff_t *off)
134 struct proxy_dev *proxy_dev = filp->private_data;
136 mutex_lock(&proxy_dev->buf_lock);
138 if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
139 mutex_unlock(&proxy_dev->buf_lock);
143 if (count > sizeof(proxy_dev->buffer) ||
144 !(proxy_dev->state & STATE_WAIT_RESPONSE_FLAG)) {
145 mutex_unlock(&proxy_dev->buf_lock);
149 proxy_dev->state &= ~STATE_WAIT_RESPONSE_FLAG;
151 proxy_dev->req_len = 0;
153 if (copy_from_user(proxy_dev->buffer, buf, count)) {
154 mutex_unlock(&proxy_dev->buf_lock);
158 proxy_dev->resp_len = count;
160 mutex_unlock(&proxy_dev->buf_lock);
162 wake_up_interruptible(&proxy_dev->wq);
168 * vtpm_proxy_fops_poll - Poll status on 'server side'
170 * @filp: file pointer
175 static unsigned int vtpm_proxy_fops_poll(struct file *filp, poll_table *wait)
177 struct proxy_dev *proxy_dev = filp->private_data;
180 poll_wait(filp, &proxy_dev->wq, wait);
184 mutex_lock(&proxy_dev->buf_lock);
186 if (proxy_dev->req_len)
187 ret |= POLLIN | POLLRDNORM;
189 if (!(proxy_dev->state & STATE_OPENED_FLAG))
192 mutex_unlock(&proxy_dev->buf_lock);
198 * vtpm_proxy_fops_open - Open vTPM device on 'server side'
200 * @filp: file pointer
202 * Called when setting up the anonymous file descriptor
204 static void vtpm_proxy_fops_open(struct file *filp)
206 struct proxy_dev *proxy_dev = filp->private_data;
208 proxy_dev->state |= STATE_OPENED_FLAG;
212 * vtpm_proxy_fops_undo_open - counter-part to vtpm_fops_open
213 * Call to undo vtpm_proxy_fops_open
215 *@proxy_dev: tpm proxy device
217 static void vtpm_proxy_fops_undo_open(struct proxy_dev *proxy_dev)
219 mutex_lock(&proxy_dev->buf_lock);
221 proxy_dev->state &= ~STATE_OPENED_FLAG;
223 mutex_unlock(&proxy_dev->buf_lock);
225 /* no more TPM responses -- wake up anyone waiting for them */
226 wake_up_interruptible(&proxy_dev->wq);
230 * vtpm_proxy_fops_release - Close 'server side'
233 * @filp: file pointer
237 static int vtpm_proxy_fops_release(struct inode *inode, struct file *filp)
239 struct proxy_dev *proxy_dev = filp->private_data;
241 filp->private_data = NULL;
243 vtpm_proxy_delete_device(proxy_dev);
248 static const struct file_operations vtpm_proxy_fops = {
249 .owner = THIS_MODULE,
251 .read = vtpm_proxy_fops_read,
252 .write = vtpm_proxy_fops_write,
253 .poll = vtpm_proxy_fops_poll,
254 .release = vtpm_proxy_fops_release,
258 * Functions invoked by the core TPM driver to send TPM commands to
259 * 'server side' and receive responses from there.
263 * Called when core TPM driver reads TPM responses from 'server side'
265 * @chip: tpm chip to use
266 * @buf: receive buffer
267 * @count: bytes to read
269 * Number of TPM response bytes read, negative error value otherwise
271 static int vtpm_proxy_tpm_op_recv(struct tpm_chip *chip, u8 *buf, size_t count)
273 struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
277 mutex_lock(&proxy_dev->buf_lock);
279 if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
280 mutex_unlock(&proxy_dev->buf_lock);
284 len = proxy_dev->resp_len;
287 "Invalid size in recv: count=%zd, resp_len=%zd\n",
293 memcpy(buf, proxy_dev->buffer, len);
294 proxy_dev->resp_len = 0;
297 mutex_unlock(&proxy_dev->buf_lock);
303 * Called when core TPM driver forwards TPM requests to 'server side'.
305 * @chip: tpm chip to use
307 * @count: bytes to send
310 * 0 in case of success, negative error value otherwise.
312 static int vtpm_proxy_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t count)
314 struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
317 if (count > sizeof(proxy_dev->buffer)) {
319 "Invalid size in send: count=%zd, buffer size=%zd\n",
320 count, sizeof(proxy_dev->buffer));
324 mutex_lock(&proxy_dev->buf_lock);
326 if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
327 mutex_unlock(&proxy_dev->buf_lock);
331 proxy_dev->resp_len = 0;
333 proxy_dev->req_len = count;
334 memcpy(proxy_dev->buffer, buf, count);
336 proxy_dev->state &= ~STATE_WAIT_RESPONSE_FLAG;
338 mutex_unlock(&proxy_dev->buf_lock);
340 wake_up_interruptible(&proxy_dev->wq);
345 static void vtpm_proxy_tpm_op_cancel(struct tpm_chip *chip)
350 static u8 vtpm_proxy_tpm_op_status(struct tpm_chip *chip)
352 struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
354 if (proxy_dev->resp_len)
355 return VTPM_PROXY_REQ_COMPLETE_FLAG;
360 static bool vtpm_proxy_tpm_req_canceled(struct tpm_chip *chip, u8 status)
362 struct proxy_dev *proxy_dev = dev_get_drvdata(&chip->dev);
365 mutex_lock(&proxy_dev->buf_lock);
367 ret = !(proxy_dev->state & STATE_OPENED_FLAG);
369 mutex_unlock(&proxy_dev->buf_lock);
374 static const struct tpm_class_ops vtpm_proxy_tpm_ops = {
375 .flags = TPM_OPS_AUTO_STARTUP,
376 .recv = vtpm_proxy_tpm_op_recv,
377 .send = vtpm_proxy_tpm_op_send,
378 .cancel = vtpm_proxy_tpm_op_cancel,
379 .status = vtpm_proxy_tpm_op_status,
380 .req_complete_mask = VTPM_PROXY_REQ_COMPLETE_FLAG,
381 .req_complete_val = VTPM_PROXY_REQ_COMPLETE_FLAG,
382 .req_canceled = vtpm_proxy_tpm_req_canceled,
386 * Code related to the startup of the TPM 2 and startup of TPM 1.2 +
387 * retrieval of timeouts and durations.
390 static void vtpm_proxy_work(struct work_struct *work)
392 struct proxy_dev *proxy_dev = container_of(work, struct proxy_dev,
396 rc = tpm_chip_register(proxy_dev->chip);
398 vtpm_proxy_fops_undo_open(proxy_dev);
400 proxy_dev->state |= STATE_REGISTERED_FLAG;
404 * vtpm_proxy_work_stop: make sure the work has finished
406 * This function is useful when user space closed the fd
407 * while the driver still determines timeouts.
409 static void vtpm_proxy_work_stop(struct proxy_dev *proxy_dev)
411 vtpm_proxy_fops_undo_open(proxy_dev);
412 flush_work(&proxy_dev->work);
416 * vtpm_proxy_work_start: Schedule the work for TPM 1.2 & 2 initialization
418 static inline void vtpm_proxy_work_start(struct proxy_dev *proxy_dev)
420 queue_work(workqueue, &proxy_dev->work);
424 * Code related to creation and deletion of device pairs
426 static struct proxy_dev *vtpm_proxy_create_proxy_dev(void)
428 struct proxy_dev *proxy_dev;
429 struct tpm_chip *chip;
432 proxy_dev = kzalloc(sizeof(*proxy_dev), GFP_KERNEL);
433 if (proxy_dev == NULL)
434 return ERR_PTR(-ENOMEM);
436 init_waitqueue_head(&proxy_dev->wq);
437 mutex_init(&proxy_dev->buf_lock);
438 INIT_WORK(&proxy_dev->work, vtpm_proxy_work);
440 chip = tpm_chip_alloc(NULL, &vtpm_proxy_tpm_ops);
443 goto err_proxy_dev_free;
445 dev_set_drvdata(&chip->dev, proxy_dev);
447 proxy_dev->chip = chip;
458 * Undo what has been done in vtpm_create_proxy_dev
460 static inline void vtpm_proxy_delete_proxy_dev(struct proxy_dev *proxy_dev)
462 put_device(&proxy_dev->chip->dev); /* frees chip */
467 * Create a /dev/tpm%d and 'server side' file descriptor pair
470 * Returns file pointer on success, an error value otherwise
472 static struct file *vtpm_proxy_create_device(
473 struct vtpm_proxy_new_dev *vtpm_new_dev)
475 struct proxy_dev *proxy_dev;
479 if (vtpm_new_dev->flags & ~VTPM_PROXY_FLAGS_ALL)
480 return ERR_PTR(-EOPNOTSUPP);
482 proxy_dev = vtpm_proxy_create_proxy_dev();
483 if (IS_ERR(proxy_dev))
484 return ERR_CAST(proxy_dev);
486 proxy_dev->flags = vtpm_new_dev->flags;
488 /* setup an anonymous file for the server-side */
489 fd = get_unused_fd_flags(O_RDWR);
492 goto err_delete_proxy_dev;
495 file = anon_inode_getfile("[vtpms]", &vtpm_proxy_fops, proxy_dev,
499 goto err_put_unused_fd;
502 /* from now on we can unwind with put_unused_fd() + fput() */
503 /* simulate an open() on the server side */
504 vtpm_proxy_fops_open(file);
506 if (proxy_dev->flags & VTPM_PROXY_FLAG_TPM2)
507 proxy_dev->chip->flags |= TPM_CHIP_FLAG_TPM2;
509 vtpm_proxy_work_start(proxy_dev);
511 vtpm_new_dev->fd = fd;
512 vtpm_new_dev->major = MAJOR(proxy_dev->chip->dev.devt);
513 vtpm_new_dev->minor = MINOR(proxy_dev->chip->dev.devt);
514 vtpm_new_dev->tpm_num = proxy_dev->chip->dev_num;
521 err_delete_proxy_dev:
522 vtpm_proxy_delete_proxy_dev(proxy_dev);
528 * Counter part to vtpm_create_device.
530 static void vtpm_proxy_delete_device(struct proxy_dev *proxy_dev)
532 vtpm_proxy_work_stop(proxy_dev);
535 * A client may hold the 'ops' lock, so let it know that the server
536 * side shuts down before we try to grab the 'ops' lock when
537 * unregistering the chip.
539 vtpm_proxy_fops_undo_open(proxy_dev);
541 if (proxy_dev->state & STATE_REGISTERED_FLAG)
542 tpm_chip_unregister(proxy_dev->chip);
544 vtpm_proxy_delete_proxy_dev(proxy_dev);
548 * Code related to the control device /dev/vtpmx
552 * vtpmx_ioc_new_dev - handler for the %VTPM_PROXY_IOC_NEW_DEV ioctl
554 * @ioctl: the ioctl number
555 * @arg: pointer to the struct vtpmx_proxy_new_dev
557 * Creates an anonymous file that is used by the process acting as a TPM to
558 * communicate with the client processes. The function will also add a new TPM
559 * device through which data is proxied to this TPM acting process. The caller
560 * will be provided with a file descriptor to communicate with the clients and
561 * major and minor numbers for the TPM device.
563 static long vtpmx_ioc_new_dev(struct file *file, unsigned int ioctl,
566 void __user *argp = (void __user *)arg;
567 struct vtpm_proxy_new_dev __user *vtpm_new_dev_p;
568 struct vtpm_proxy_new_dev vtpm_new_dev;
569 struct file *vtpm_file;
571 if (!capable(CAP_SYS_ADMIN))
574 vtpm_new_dev_p = argp;
576 if (copy_from_user(&vtpm_new_dev, vtpm_new_dev_p,
577 sizeof(vtpm_new_dev)))
580 vtpm_file = vtpm_proxy_create_device(&vtpm_new_dev);
581 if (IS_ERR(vtpm_file))
582 return PTR_ERR(vtpm_file);
584 if (copy_to_user(vtpm_new_dev_p, &vtpm_new_dev,
585 sizeof(vtpm_new_dev))) {
586 put_unused_fd(vtpm_new_dev.fd);
591 fd_install(vtpm_new_dev.fd, vtpm_file);
596 * vtpmx_fops_ioctl: ioctl on /dev/vtpmx
599 * Returns 0 on success, a negative error code otherwise.
601 static long vtpmx_fops_ioctl(struct file *f, unsigned int ioctl,
605 case VTPM_PROXY_IOC_NEW_DEV:
606 return vtpmx_ioc_new_dev(f, ioctl, arg);
613 static long vtpmx_fops_compat_ioctl(struct file *f, unsigned int ioctl,
616 return vtpmx_fops_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
620 static const struct file_operations vtpmx_fops = {
621 .owner = THIS_MODULE,
622 .unlocked_ioctl = vtpmx_fops_ioctl,
624 .compat_ioctl = vtpmx_fops_compat_ioctl,
626 .llseek = noop_llseek,
629 static struct miscdevice vtpmx_miscdev = {
630 .minor = MISC_DYNAMIC_MINOR,
635 static int vtpmx_init(void)
637 return misc_register(&vtpmx_miscdev);
640 static void vtpmx_cleanup(void)
642 misc_deregister(&vtpmx_miscdev);
645 static int __init vtpm_module_init(void)
651 pr_err("couldn't create vtpmx device\n");
655 workqueue = create_workqueue("tpm-vtpm");
657 pr_err("couldn't create workqueue\n");
659 goto err_vtpmx_cleanup;
670 static void __exit vtpm_module_exit(void)
672 destroy_workqueue(workqueue);
676 module_init(vtpm_module_init);
677 module_exit(vtpm_module_exit);
679 MODULE_AUTHOR("Stefan Berger (stefanb@us.ibm.com)");
680 MODULE_DESCRIPTION("vTPM Driver");
681 MODULE_VERSION("0.1");
682 MODULE_LICENSE("GPL");