[PATCH AUTOSEL 5.6 290/606] Input: evdev - call input_flush_device() on release(), not flush()

Sasha Levin
2020-06-09T00:20:14Z

From: Brendan Shanks <bshanks@codeweavers.com>

[ Upstream commit 09264098ff153f60866039d60b31d39b66f55a31 ]

input_flush_device() should only be called once the struct file is being
released and no open descriptors remain, but evdev_flush() was calling
it whenever a file descriptor was closed.

This caused uploaded force-feedback effects to be erased when a process
did a dup()/close() on the event FD, called system(), etc.

Call input_flush_device() from evdev_release() instead.

Reported-by: Mathieu Maret <mathieu.maret@gmail.com>
Signed-off-by: Brendan Shanks <bshanks@codeweavers.com>
Link: https://lore.kernel.org/r/20200421231003.7935-1-bshanks@codeweavers.com
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/input/evdev.c | 19 ++++---------------
1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index cb6e3a5f509c..0d57e51b8ba1 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -326,20 +326,6 @@ static int evdev_fasync(int fd, struct file *file, int on)
return fasync_helper(fd, file, on, &client->fasync);
}

-static int evdev_flush(struct file *file, fl_owner_t id)
-{
- struct evdev_client *client = file->private_data;
- struct evdev *evdev = client->evdev;
-
- mutex_lock(&evdev->mutex);
-
- if (evdev->exist && !client->revoked)
- input_flush_device(&evdev->handle, file);
-
- mutex_unlock(&evdev->mutex);
- return 0;
-}
-
static void evdev_free(struct device *dev)
{
struct evdev *evdev = container_of(dev, struct evdev, dev);
@@ -453,6 +439,10 @@ static int evdev_release(struct inode *inode, struct file *file)
unsigned int i;

mutex_lock(&evdev->mutex);
+
+ if (evdev->exist && !client->revoked)
+ input_flush_device(&evdev->handle, file);
+
evdev_ungrab(evdev, client);
mutex_unlock(&evdev->mutex);

@@ -1310,7 +1300,6 @@ static const struct file_operations evdev_fops = {
.compat_ioctl = evdev_ioctl_compat,
#endif
.fasync = evdev_fasync,
- .flush = evdev_flush,
.llseek = no_llseek,
};

--
2.25.1