[PATCH bpf-next] xsk: proper socket state check in xsk_poll
From: Björn Töpel <hidden>
Date: 2019-08-20 10:05:02
Also in:
bpf, lkml
Subsystem:
networking [general], the rest, xdp sockets (af_xdp) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Magnus Karlsson, Maciej Fijalkowski
From: Björn Töpel <redacted>
The poll() implementation for AF_XDP sockets did not perform the
proper state checks, prior accessing the socket umem. This patch fixes
that by performing a xsk_is_bound() check.
Suggested-by: Hillf Danton <redacted>
Reported-by: syzbot+c82697e3043781e08802@syzkaller.appspotmail.com
Fixes: 77cd0d7b3f25 ("xsk: add support for need_wakeup flag in AF_XDP rings")
Signed-off-by: Björn Töpel <redacted>
---
net/xdp/xsk.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index ee4428a892fa..08bed5e92af4 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c@@ -356,13 +356,20 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m, return err; } +static bool xsk_is_bound(struct xdp_sock *xs) +{ + struct net_device *dev = READ_ONCE(xs->dev); + + return dev && xs->state == XSK_BOUND; +} + static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) { bool need_wait = !(m->msg_flags & MSG_DONTWAIT); struct sock *sk = sock->sk; struct xdp_sock *xs = xdp_sk(sk); - if (unlikely(!xs->dev)) + if (unlikely(!xsk_is_bound(xs))) return -ENXIO; if (unlikely(!(xs->dev->flags & IFF_UP))) return -ENETDOWN;
@@ -383,6 +390,9 @@ static unsigned int xsk_poll(struct file *file, struct socket *sock, struct net_device *dev = xs->dev; struct xdp_umem *umem = xs->umem; + if (unlikely(!xsk_is_bound(xs))) + return mask; + if (umem->need_wakeup) dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id, umem->need_wakeup);
@@ -417,7 +427,7 @@ static void xsk_unbind_dev(struct xdp_sock *xs) { struct net_device *dev = xs->dev; - if (!dev || xs->state != XSK_BOUND) + if (!xsk_is_bound(xs)) return; xs->state = XSK_UNBOUND;
--
2.20.1