tpm: Fix error handling in async work

commit 2e8e4c8f6673247e22efc7985ce5497accd16f88 upstream.

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>
Cc: Tadeusz Struk <tadeusz.struk@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index 1784530b8387bb46bec8694a49ddb5385833be80..b99e1941c52c98359863ed1bfb9c785ed22ceabe 100644 (file)
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -70,7 +70,13 @@ 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));
        }