[PATCH 06/13] vfio: use get_unused_fd_flags(0) instead of get_unused_fd()

Yann Droneaud
2013-07-02T16:39:30Z

Macro get_unused_fd() is used to allocate a file descriptor with
default flags. Those default flags (0) can be "unsafe":
O_CLOEXEC must be used by default to not leak file descriptor
across exec().

Instead of macro get_unused_fd(), functions anon_inode_getfd()
or get_unused_fd_flags() should be used with flags given by userspace.
If not possible, flags should be set to O_CLOEXEC to provide userspace
with a default safe behavor.

In a further patch, get_unused_fd() will be removed so that
new code start using anon_inode_getfd() or get_unused_fd_flags()
with correct flags.

This patch replaces calls to get_unused_fd() with equivalent call to
get_unused_fd_flags(0) to preserve current behavor for existing code.

The hard coded flag value (0) should be reviewed on a per-subsystem basis,
and, if possible, set to O_CLOEXEC.

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
---
drivers/vfio/vfio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index c488da5..bb4e9fd 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1126,7 +1126,7 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
* We can't use anon_inode_getfd() because we need to modify
* the f_mode flags directly to allow more than just ioctls
*/
- ret = get_unused_fd();
+ ret = get_unused_fd_flags(0);
if (ret < 0) {
device->ops->release(device->device_data);
break;
--
1.8.3.1