| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2004 IBM Corporation |
| * Authors: |
| * Leendert van Doorn <leendert@watson.ibm.com> |
| * Dave Safford <safford@watson.ibm.com> |
| * Reiner Sailer <sailer@watson.ibm.com> |
| * Kylene Hall <kjhall@us.ibm.com> |
| * |
| * Copyright (C) 2013 Obsidian Research Corp |
| * Jason Gunthorpe <jgunthorpe@obsidianresearch.com> |
| * |
| * Device file system interface to the TPM |
| */ |
| #include <linux/poll.h> |
| #include <linux/slab.h> |
| #include <linux/uaccess.h> |
| #include <linux/workqueue.h> |
| #include "tpm.h" |
| #include "tpm-dev.h" |
| |
| static struct workqueue_struct *tpm_dev_wq; |
| static DEFINE_MUTEX(tpm_dev_wq_lock); |
| |
| static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space, |
| u8 *buf, size_t bufsiz) |
| { |
| struct tpm_header *header = (void *)buf; |
| ssize_t ret, len; |
| |
| ret = tpm2_prepare_space(chip, space, buf, bufsiz); |
| /* If the command is not implemented by the TPM, synthesize a |
| * response with a TPM2_RC_COMMAND_CODE return for user-space. |
| */ |
| if (ret == -EOPNOTSUPP) { |
| header->length = cpu_to_be32(sizeof(*header)); |
| header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS); |
| header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE | |
| TSS2_RESMGR_TPM_RC_LAYER); |
| ret = sizeof(*header); |
| } |
| if (ret) |
| goto out_rc; |
| |
| len = tpm_transmit(chip, buf, bufsiz); |
| if (len < 0) |
| ret = len; |
| |
| if (!ret) |
| ret = tpm2_commit_space(chip, space, buf, &len); |
| |
| out_rc: |
| return ret ? ret : len; |
| } |
| |
| static void tpm_dev_async_work(struct work_struct *work) |
| { |
| struct file_priv *priv = |
| container_of(work, struct file_priv, async_work); |
| ssize_t ret; |
| |
| mutex_lock(&priv->buffer_mutex); |
| priv->command_enqueued = false; |
| ret = tpm_try_get_ops(priv->chip); |
| if (ret) { |
| priv->response_length = ret; |
| goto out; |
| } |
| |
| ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer, |
| sizeof(priv->data_buffer)); |
| tpm_put_ops(priv->chip); |
| if (ret > 0) { |
| priv->response_length = ret; |
| mod_timer(&priv->user_read_timer, jiffies + (120 * HZ)); |
| } |
| out: |
| mutex_unlock(&priv->buffer_mutex); |
| wake_up_interruptible(&priv->async_wait); |
| } |
| |
| static void user_reader_timeout(struct timer_list *t) |
| { |
| struct file_priv *priv = from_timer(priv, t, user_read_timer); |
| |
| pr_warn("TPM user space timeout is deprecated (pid=%d)\n", |
| task_tgid_nr(current)); |
| |
| schedule_work(&priv->timeout_work); |
| } |
| |
| static void tpm_timeout_work(struct work_struct *work) |
| { |
| struct file_priv *priv = container_of(work, struct file_priv, |
| timeout_work); |
| |
| mutex_lock(&priv->buffer_mutex); |
| priv->response_read = true; |
| priv->response_length = 0; |
| memset(priv->data_buffer, 0, sizeof(priv->data_buffer)); |
| mutex_unlock(&priv->buffer_mutex); |
| wake_up_interruptible(&priv->async_wait); |
| } |
| |
| void tpm_common_open(struct file *file, struct tpm_chip *chip, |
| struct file_priv *priv, struct tpm_space *space) |
| { |
| priv->chip = chip; |
| priv->space = space; |
| priv->response_read = true; |
| |
| mutex_init(&priv->buffer_mutex); |
| timer_setup(&priv->user_read_timer, user_reader_timeout, 0); |
| INIT_WORK(&priv->timeout_work, tpm_timeout_work); |
| INIT_WORK(&priv->async_work, tpm_dev_async_work); |
| init_waitqueue_head(&priv->async_wait); |
| file->private_data = priv; |
| } |
| |
| ssize_t tpm_common_read(struct file *file, char __user *buf, |
| size_t size, loff_t *off) |
| { |
| struct file_priv *priv = file->private_data; |
| ssize_t ret_size = 0; |
| int rc; |
| |
| mutex_lock(&priv->buffer_mutex); |
| |
| if (priv->response_length) { |
| priv->response_read = true; |
| |
| ret_size = min_t(ssize_t, size, priv->response_length); |
| if (ret_size <= 0) { |
| priv->response_length = 0; |
| goto out; |
| } |
| |
| rc = copy_to_user(buf, priv->data_buffer + *off, ret_size); |
| if (rc) { |
| memset(priv->data_buffer, 0, TPM_BUFSIZE); |
| priv->response_length = 0; |
| ret_size = -EFAULT; |
| } else { |
| memset(priv->data_buffer + *off, 0, ret_size); |
| priv->response_length -= ret_size; |
| *off += ret_size; |
| } |
| } |
| |
| out: |
| if (!priv->response_length) { |
| *off = 0; |
| del_singleshot_timer_sync(&priv->user_read_timer); |
| flush_work(&priv->timeout_work); |
| } |
| mutex_unlock(&priv->buffer_mutex); |
| return ret_size; |
| } |
| |
| ssize_t tpm_common_write(struct file *file, const char __user *buf, |
| size_t size, loff_t *off) |
| { |
| struct file_priv *priv = file->private_data; |
| int ret = 0; |
| |
| if (size > TPM_BUFSIZE) |
| return -E2BIG; |
| |
| mutex_lock(&priv->buffer_mutex); |
| |
| /* Cannot perform a write until the read has cleared either via |
| * tpm_read or a user_read_timer timeout. This also prevents split |
| * buffered writes from blocking here. |
| */ |
| if ((!priv->response_read && priv->response_length) || |
| priv->command_enqueued) { |
| ret = -EBUSY; |
| goto out; |
| } |
| |
| if (copy_from_user(priv->data_buffer, buf, size)) { |
| ret = -EFAULT; |
| goto out; |
| } |
| |
| if (size < 6 || |
| size < be32_to_cpu(*((__be32 *)(priv->data_buffer + 2)))) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| /* atomic tpm command send and result receive. We only hold the ops |
| * lock during this period so that the tpm can be unregistered even if |
| * the char dev is held open. |
| */ |
| if (tpm_try_get_ops(priv->chip)) { |
| ret = -EPIPE; |
| goto out; |
| } |
| |
| priv->response_length = 0; |
| priv->response_read = false; |
| *off = 0; |
| |
| /* |
| * If in nonblocking mode schedule an async job to send |
| * the command return the size. |
| * In case of error the err code will be returned in |
| * the subsequent read call. |
| */ |
| if (file->f_flags & O_NONBLOCK) { |
| priv->command_enqueued = true; |
| queue_work(tpm_dev_wq, &priv->async_work); |
| tpm_put_ops(priv->chip); |
| mutex_unlock(&priv->buffer_mutex); |
| return size; |
| } |
| |
| ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer, |
| sizeof(priv->data_buffer)); |
| tpm_put_ops(priv->chip); |
| |
| if (ret > 0) { |
| priv->response_length = ret; |
| mod_timer(&priv->user_read_timer, jiffies + (120 * HZ)); |
| ret = size; |
| } |
| out: |
| mutex_unlock(&priv->buffer_mutex); |
| return ret; |
| } |
| |
| __poll_t tpm_common_poll(struct file *file, poll_table *wait) |
| { |
| struct file_priv *priv = file->private_data; |
| __poll_t mask = 0; |
| |
| poll_wait(file, &priv->async_wait, wait); |
| mutex_lock(&priv->buffer_mutex); |
| |
| /* |
| * The response_length indicates if there is still response |
| * (or part of it) to be consumed. Partial reads decrease it |
| * by the number of bytes read, and write resets it the zero. |
| */ |
| if (priv->response_length) |
| mask = EPOLLIN | EPOLLRDNORM; |
| else |
| mask = EPOLLOUT | EPOLLWRNORM; |
| |
| mutex_unlock(&priv->buffer_mutex); |
| return mask; |
| } |
| |
| /* |
| * Called on file close |
| */ |
| void tpm_common_release(struct file *file, struct file_priv *priv) |
| { |
| flush_work(&priv->async_work); |
| del_singleshot_timer_sync(&priv->user_read_timer); |
| flush_work(&priv->timeout_work); |
| file->private_data = NULL; |
| priv->response_length = 0; |
| } |
| |
| int __init tpm_dev_common_init(void) |
| { |
| tpm_dev_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0); |
| |
| return !tpm_dev_wq ? -ENOMEM : 0; |
| } |
| |
| void __exit tpm_dev_common_exit(void) |
| { |
| if (tpm_dev_wq) { |
| destroy_workqueue(tpm_dev_wq); |
| tpm_dev_wq = NULL; |
| } |
| } |