From:   Tadeusz Struk <tstruk@gmail.com>
To:     jarkko@kernel.org
Cc:     Tadeusz Struk <tstruk@gmail.com>, Jason Gunthorpe <jgg@ziepe.ca>,
        linux-integrity@vger.kernel.org, stable@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] tpm: Fix error handling in async work
Date:   Mon, 20 Dec 2021 13:16:59 -0800
Message-Id: <20211220211700.5772-1-tstruk@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When an invalid (non exitsinting) 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
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 causing the userspace
code to get stack. Make sure that error conditions also contribute
to the poll mask so that 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")
Signed-off-by: Tadeusz Struk <tstruk@gmail.com>
---
 drivers/char/tpm/tpm-dev-common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index c08cbb306636..fe2679f84cb6 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -69,7 +69,7 @@ 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 != 0) {
 		priv->response_length = ret;
 		mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
 	}
-- 
2.30.2