| Message ID | 1599037569-26690-1-git-send-email-magnus.karlsson@intel.com |
|---|---|
| State | Accepted |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [bpf-next] xsk: fix possible segfault at xskmap entry insertion | expand |
On 9/2/20 11:06 AM, Magnus Karlsson wrote: > Fix possible segfault when entry is inserted into xskmap. This can > happen if the socket is in a state where the umem has been set up, the > Rx ring created but it has yet to be bound to a device. In this case > the pool has not yet been created and we cannot reference it for the > existence of the fill ring. Fix this by removing the whole > xsk_is_setup_for_bpf_map function. Once upon a time, it was used to > make sure that the Rx and fill rings where set up before the driver > could call xsk_rcv, since there are no tests for the existence of > these rings in the data path. But these days, we have a state variable > that we test instead. When it is XSK_BOUND, everything has been set up > correctly and the socket has been bound. So no reason to have the > xsk_is_setup_for_bpf_map function anymore. > > Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> > Reported-by: syzbot+febe51d44243fbc564ee@syzkaller.appspotmail.com > Fixes: 7361f9c3d719 ("xsk: move fill and completion rings to buffer pool") Applied & corrected Fixes tag, thanks!
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 5eb6662..07c3227 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -33,12 +33,6 @@ static DEFINE_PER_CPU(struct list_head, xskmap_flush_list); -bool xsk_is_setup_for_bpf_map(struct xdp_sock *xs) -{ - return READ_ONCE(xs->rx) && READ_ONCE(xs->umem) && - (xs->pool->fq || READ_ONCE(xs->fq_tmp)); -} - void xsk_set_rx_need_wakeup(struct xsk_buff_pool *pool) { if (pool->cached_need_wakeup & XDP_WAKEUP_RX) diff --git a/net/xdp/xsk.h b/net/xdp/xsk.h index da1f73e..b9e896c 100644 --- a/net/xdp/xsk.h +++ b/net/xdp/xsk.h @@ -39,7 +39,6 @@ static inline struct xdp_sock *xdp_sk(struct sock *sk) return (struct xdp_sock *)sk; } -bool xsk_is_setup_for_bpf_map(struct xdp_sock *xs); void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs, struct xdp_sock **map_entry); int xsk_map_inc(struct xsk_map *map); diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c index 2a4fd66..0c5df59 100644 --- a/net/xdp/xskmap.c +++ b/net/xdp/xskmap.c @@ -185,11 +185,6 @@ static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value, xs = (struct xdp_sock *)sock->sk; - if (!xsk_is_setup_for_bpf_map(xs)) { - sockfd_put(sock); - return -EOPNOTSUPP; - } - map_entry = &m->xsk_map[i]; node = xsk_map_node_alloc(m, map_entry); if (IS_ERR(node)) {
Fix possible segfault when entry is inserted into xskmap. This can happen if the socket is in a state where the umem has been set up, the Rx ring created but it has yet to be bound to a device. In this case the pool has not yet been created and we cannot reference it for the existence of the fill ring. Fix this by removing the whole xsk_is_setup_for_bpf_map function. Once upon a time, it was used to make sure that the Rx and fill rings where set up before the driver could call xsk_rcv, since there are no tests for the existence of these rings in the data path. But these days, we have a state variable that we test instead. When it is XSK_BOUND, everything has been set up correctly and the socket has been bound. So no reason to have the xsk_is_setup_for_bpf_map function anymore. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Reported-by: syzbot+febe51d44243fbc564ee@syzkaller.appspotmail.com Fixes: 7361f9c3d719 ("xsk: move fill and completion rings to buffer pool") --- net/xdp/xsk.c | 6 ------ net/xdp/xsk.h | 1 - net/xdp/xskmap.c | 5 ----- 3 files changed, 12 deletions(-)