vfio: use get_unused_fd_flags(0) instead of get_unused_fd()

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>
Link: http://lkml.kernel.org/r/cover.1376327678.git.ydroneaud@opteya.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Yann Droneaud 2013-08-22 10:20:05 -06:00 committed by Alex Williamson
parent 6cdd978213
commit a5d550703d

View File

@ -1109,7 +1109,7 @@ 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;