From: "Björn Töpel" <bjorn.topel@gmail.com>
To: syzbot+c82697e3043781e08802@syzkaller.appspotmail.com,
ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org
Cc: bjorn.topel@intel.com, bpf@vger.kernel.org, davem@davemloft.net,
hawk@kernel.org, jakub.kicinski@netronome.com,
john.fastabend@gmail.com, jonathan.lemon@gmail.com, kafai@fb.com,
linux-kernel@vger.kernel.org, magnus.karlsson@intel.com,
songliubraving@fb.com, syzkaller-bugs@googlegroups.com,
xdp-newbies@vger.kernel.org, yhs@fb.com, hdanton@sina.com
Subject: [PATCH bpf-next] xsk: proper socket state check in xsk_poll
Date: Tue, 20 Aug 2019 12:04:05 +0200 [thread overview]
Message-ID: <20190820100405.25564-1-bjorn.topel@gmail.com> (raw)
In-Reply-To: <0000000000009167320590823a8c@google.com>
From: Björn Töpel <bjorn.topel@intel.com>
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 <hdanton@sina.com>
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 <bjorn.topel@intel.com>
---
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
next prev parent reply other threads:[~2019-08-20 10:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-20 1:18 general protection fault in xsk_poll syzbot
2019-08-20 10:04 ` Björn Töpel [this message]
2019-08-20 14:30 ` [PATCH bpf-next] xsk: proper socket state check " Daniel Borkmann
2019-08-20 15:29 ` Björn Töpel
2019-08-20 21:24 ` Daniel Borkmann
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