tpm-dev: Require response to be read only if there actually is a response
diff mbox series

Message ID 20181206175801.23048-1-Alexander.Steffen@infineon.com
State New
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Series
  • tpm-dev: Require response to be read only if there actually is a response
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Commit Message

Alexander Steffen Dec. 6, 2018, 5:58 p.m. UTC
If the tpm_transmit call in tpm_common_write fails for any reason, there is
no response that could be read. Therefore, do not require the application
to issue a read call before sending further commands. This restores the
behavior from before support for partial reads was introduced.

Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
---
Feel free to merge this into Tadeusz' original commit.

 drivers/char/tpm/tpm-dev-common.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Jarkko Sakkinen Dec. 12, 2018, 5:53 p.m. UTC | #1
On Thu, Dec 06, 2018 at 06:58:01PM +0100, Alexander Steffen wrote:
> If the tpm_transmit call in tpm_common_write fails for any reason, there is
> no response that could be read. Therefore, do not require the application
> to issue a read call before sending further commands. This restores the
> behavior from before support for partial reads was introduced.
> 
> Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
> ---
> Feel free to merge this into Tadeusz' original commit.

Thank you, good catch.

My PR is a bit late becuse just came from Oregon back to Finland so
I'll follow your advice and squash this. Thanks again.

/Jarkko

Patch
diff mbox series

diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index 344739223451..5eecad233ea1 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -140,7 +140,8 @@  ssize_t tpm_common_write(struct file *file, const char __user *buf,
 	 * tpm_read or a user_read_timer timeout. This also prevents split
 	 * buffered writes from blocking here.
 	 */
-	if (!priv->response_read || priv->command_enqueued) {
+	if ((!priv->response_read && priv->response_length) ||
+	    priv->command_enqueued) {
 		ret = -EBUSY;
 		goto out;
 	}