[PATCH v7 09/10] tpm: Initialize TPM and get durations and timeouts

Stefan Berger
2016-03-12T02:52:04Z

Add the retrieval of TPM 1.2 durations and timeouts. Since this requires
the startup of the TPM, do this for TPM 1.2 and TPM 2.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
CC: linux-kernel@vger.kernel.org
CC: linux-doc@vger.kernel.org
CC: linux-api@vger.kernel.org
---
drivers/char/tpm/tpm_vtpm_proxy.c | 95 +++++++++++++++++++++++++++++++++++----
1 file changed, 86 insertions(+), 9 deletions(-)

diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
index d73944e..9dedf48 100644
--- a/drivers/char/tpm/tpm_vtpm_proxy.c
+++ b/drivers/char/tpm/tpm_vtpm_proxy.c
@@ -45,8 +45,11 @@ struct proxy_dev {
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 */
};

+static struct workqueue_struct *workqueue;

static void vtpm_proxy_delete_device(struct proxy_dev *proxy_dev);

@@ -67,6 +70,15 @@ static ssize_t vtpm_proxy_fops_read(struct file *filp, char __user *buf,
size_t len;
int sig, rc;

+ mutex_lock(&proxy_dev->buf_lock);
+
+ if (!(proxy_dev->state & STATE_OPENED_FLAG)) {
+ mutex_unlock(&proxy_dev->buf_lock);
+ return -EPIPE;
+ }
+
+ mutex_unlock(&proxy_dev->buf_lock);
+
sig = wait_event_interruptible(proxy_dev->wq, proxy_dev->req_len != 0);
if (sig)
return -EINTR;
@@ -110,6 +122,11 @@ static ssize_t vtpm_proxy_fops_write(struct file *filp, const char __user *buf,

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);
@@ -154,6 +171,9 @@ static unsigned int vtpm_proxy_fops_poll(struct file *filp, poll_table *wait)
if (proxy_dev->req_len)
ret |= POLLIN | POLLRDNORM;

+ if (!(proxy_dev->state & STATE_OPENED_FLAG))
+ ret |= POLLHUP;
+
mutex_unlock(&proxy_dev->buf_lock);

return ret;
@@ -341,6 +361,55 @@ static const struct tpm_class_ops vtpm_proxy_tpm_ops = {
};

/*
+ * 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;
+
+ if (proxy_dev->flags & VTPM_PROXY_FLAG_TPM2)
+ rc = tpm2_startup(proxy_dev->chip, TPM2_SU_CLEAR);
+ else
+ rc = tpm_get_timeouts(proxy_dev->chip);
+
+ if (rc)
+ goto err;
+
+ rc = tpm_chip_register(proxy_dev->chip);
+ if (rc)
+ goto err;
+
+ return;
+
+err:
+ vtpm_proxy_fops_undo_open(proxy_dev);
+}
+
+/*
+ * 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)
@@ -355,6 +424,7 @@ static struct proxy_dev *vtpm_proxy_create_proxy_dev(void)

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)) {
@@ -425,9 +495,7 @@ static struct file *vtpm_proxy_create_device(
if (proxy_dev->flags & VTPM_PROXY_FLAG_TPM2)
proxy_dev->chip->flags |= TPM_CHIP_FLAG_TPM2;

- rc = tpm_chip_register(proxy_dev->chip);
- if (rc)
- goto err_vtpm_fput;
+ vtpm_proxy_work_start(proxy_dev);

vtpm_new_dev->fd = fd;
vtpm_new_dev->major = MAJOR(proxy_dev->chip->dev.devt);
@@ -436,12 +504,6 @@ static struct file *vtpm_proxy_create_device(

return file;

-err_vtpm_fput:
- put_unused_fd(fd);
- fput(file);
-
- return ERR_PTR(rc);
-
err_put_unused_fd:
put_unused_fd(fd);

@@ -456,6 +518,8 @@ err_delete_proxy_dev:
*/
static void vtpm_proxy_delete_device(struct proxy_dev *proxy_dev)
{
+ vtpm_proxy_work_stop(proxy_dev);
+
tpm_chip_unregister(proxy_dev->chip);

vtpm_proxy_fops_undo_open(proxy_dev);
@@ -550,11 +614,24 @@ static int __init vtpm_module_init(void)
return rc;
}

+ workqueue = create_workqueue("tpm-vtpm");
+ if (!workqueue) {
+ pr_err("couldn't create workqueue\n");
+ rc = -ENOMEM;
+ goto err_vtpmx_cleanup;
+ }
+
return 0;
+
+err_vtpmx_cleanup:
+ vtpmx_cleanup();
+
+ return rc;
}

static void __exit vtpm_module_exit(void)
{
+ destroy_workqueue(workqueue);
vtpmx_cleanup();
}

--
2.4.3