On Mon, May 25, 2020 at 10:03:59AM +0200, Björn Töpel wrote: > From: Björn Töpel <bjorn.topel@xxxxxxxxx> > > The npgs member of struct xdp_umem is an u32 entity, and stores the > number of pages the UMEM consumes. The calculation of npgs > > npgs = size / PAGE_SIZE > > can overflow. > > To avoid overflow scenarios, the division is now first stored in a > u64, and the result is verified to fit into 32b. > > An alternative would be storing the npgs as a u64, however, this > wastes memory and is an unrealisticly large packet area. > > Link: https://lore.kernel.org/bpf/CACtPs=GGvV-_Yj6rbpzTVnopgi5nhMoCcTkSkYrJHGQHJWFZMQ@xxxxxxxxxxxxxx/ > Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt") > Reported-by: "Minh Bùi Quang" <minhquangbui99@xxxxxxxxx> > Signed-off-by: Björn Töpel <bjorn.topel@xxxxxxxxx> Acked-by: Jonathan Lemon <jonathan.lemon@xxxxxxxxx>
