mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-26 06:04:14 +08:00
tpm: fix an invalid condition in tpm_common_poll
The poll condition should only check response_length,
because reads should only be issued if there is data to read.
The response_read flag only prevents double writes.
The problem was that the write set the response_read to false,
enqued a tpm job, and returned. Then application called poll
which checked the response_read flag and returned EPOLLIN.
Then the application called read, but got nothing.
After all that the async_work kicked in.
Added also mutex_lock around the poll check to prevent
other possible race conditions.
Fixes: 9488585b21
("tpm: add support for partial reads")
Reported-by: Mantas Mikulėnas <grawity@gmail.com>
Tested-by: Mantas Mikulėnas <grawity@gmail.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
This commit is contained in:
parent
e891db1a18
commit
7110629263
@ -233,12 +233,19 @@ __poll_t tpm_common_poll(struct file *file, poll_table *wait)
|
|||||||
__poll_t mask = 0;
|
__poll_t mask = 0;
|
||||||
|
|
||||||
poll_wait(file, &priv->async_wait, wait);
|
poll_wait(file, &priv->async_wait, wait);
|
||||||
|
mutex_lock(&priv->buffer_mutex);
|
||||||
|
|
||||||
if (!priv->response_read || priv->response_length)
|
/*
|
||||||
|
* The response_length indicates if there is still response
|
||||||
|
* (or part of it) to be consumed. Partial reads decrease it
|
||||||
|
* by the number of bytes read, and write resets it the zero.
|
||||||
|
*/
|
||||||
|
if (priv->response_length)
|
||||||
mask = EPOLLIN | EPOLLRDNORM;
|
mask = EPOLLIN | EPOLLRDNORM;
|
||||||
else
|
else
|
||||||
mask = EPOLLOUT | EPOLLWRNORM;
|
mask = EPOLLOUT | EPOLLWRNORM;
|
||||||
|
|
||||||
|
mutex_unlock(&priv->buffer_mutex);
|
||||||
return mask;
|
return mask;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
Loading…
Reference in New Issue
Block a user