From 2e8e4c8f6673247e22efc7985ce5497accd16f88 Mon Sep 17 00:00:00 2001
From: Tadeusz Struk <tstruk@gmail.com>
Date: Sat, 15 Jan 2022 17:26:26 -0800
Subject: [PATCH] tpm: Fix error handling in async work
Git-commit: 2e8e4c8f6673247e22efc7985ce5497accd16f88
Patch-mainline: v5.18-rc1
References: git-fixes

When an invalid (non existing) handle is used in a TPM command,
that uses the resource manager interface (/dev/tpmrm0) the resource
manager tries to load it from its internal cache, but fails and
the tpm_dev_transmit returns an -EINVAL error to the caller.
The existing async handler doesn't handle these error cases
currently and the condition in the poll handler never returns
mask with EPOLLIN set.
The result is that the poll call blocks and the application gets stuck
until the user_read_timer wakes it up after 120 sec.
Change the tpm_dev_async_work function to handle error conditions
returned from tpm_dev_transmit they are also reflected in the poll mask
and a correct error code could passed back to the caller.

Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: <linux-integrity@vger.kernel.org>
Cc: <stable@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>

Fixes: 9e1b74a63f77 ("tpm: add support for nonblocking operation")
Tested-by: Jarkko Sakkinen<jarkko@kernel.org>
Signed-off-by: Tadeusz Struk <tstruk@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/char/tpm/tpm-dev-common.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index c08cbb306636..dc4c0a0a5129 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -69,7 +69,13 @@ static void tpm_dev_async_work(struct work_struct *work)
 	ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
 			       sizeof(priv->data_buffer));
 	tpm_put_ops(priv->chip);
-	if (ret > 0) {
+
+	/*
+	 * If ret is > 0 then tpm_dev_transmit returned the size of the
+	 * response. If ret is < 0 then tpm_dev_transmit failed and
+	 * returned an error code.
+	 */
+	if (ret != 0) {
 		priv->response_length = ret;
 		mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
 	}
-- 
2.31.1