On Tue, Jun 06, 2023 at 11:28:31AM -0700, Samuel Mendoza-Jonas wrote: > From: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > > commit fb4554c2232e44d595920f4d5c66cf8f7d13f9bc upstream. > > Descriptor table is a shared resource; two fget() on the same descriptor > may return different struct file references. get_tap_ptr_ring() is > called after we'd found (and pinned) the socket we'll be using and it > tries to find the private tun/tap data structures associated with it. > Redoing the lookup by the same file descriptor we'd used to get the > socket is racy - we need to same struct file. > > Thanks to Jason for spotting a braino in the original variant of patch - > I'd missed the use of fd == -1 for disabling backend, and in that case > we can end up with sock == NULL and sock != oldsock. > > Cc: stable@xxxxxxxxxx > Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> > Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> I did not sign off on this patch, where did that come from? Please be more careful. thanks, greg k-h
