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