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authorMagnus Karlsson <magnus.karlsson@intel.com>2019-10-02 08:31:59 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2019-10-03 16:34:27 +0200
commitdf551058f7a303bd3a17a4cef001349974962ce8 (patch)
tree360e624c558bbb4f5a8c419c410d6aff8e61c557 /net/xdp
parentsamples/bpf: Fix build for task_fd_query_user.c (diff)
downloadlinux-dev-df551058f7a303bd3a17a4cef001349974962ce8.tar.xz
linux-dev-df551058f7a303bd3a17a4cef001349974962ce8.zip
xsk: Fix crash in poll when device does not support ndo_xsk_wakeup
Fixes a crash in poll() when an AF_XDP socket is opened in copy mode and the bound device does not have ndo_xsk_wakeup defined. Avoid trying to call the non-existing ndo and instead call the internal xsk sendmsg function to send packets in the same way (from the application's point of view) as calling sendmsg() in any mode or poll() in zero-copy mode would have done. The application should behave in the same way independent on if zero-copy mode or copy mode is used. Fixes: 77cd0d7b3f25 ("xsk: add support for need_wakeup flag in AF_XDP rings") Reported-by: syzbot+a5765ed8cdb1cca4d249@syzkaller.appspotmail.com Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/1569997919-11541-1-git-send-email-magnus.karlsson@intel.com
Diffstat (limited to 'net/xdp')
-rw-r--r--net/xdp/xsk.c42
1 files changed, 27 insertions, 15 deletions
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index fa8fbb8fa3c8..9044073fbf22 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -305,9 +305,8 @@ out:
}
EXPORT_SYMBOL(xsk_umem_consume_tx);
-static int xsk_zc_xmit(struct sock *sk)
+static int xsk_zc_xmit(struct xdp_sock *xs)
{
- struct xdp_sock *xs = xdp_sk(sk);
struct net_device *dev = xs->dev;
return dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id,
@@ -327,11 +326,10 @@ static void xsk_destruct_skb(struct sk_buff *skb)
sock_wfree(skb);
}
-static int xsk_generic_xmit(struct sock *sk, struct msghdr *m,
- size_t total_len)
+static int xsk_generic_xmit(struct sock *sk)
{
- u32 max_batch = TX_BATCH_SIZE;
struct xdp_sock *xs = xdp_sk(sk);
+ u32 max_batch = TX_BATCH_SIZE;
bool sent_frame = false;
struct xdp_desc desc;
struct sk_buff *skb;
@@ -394,6 +392,18 @@ out:
return err;
}
+static int __xsk_sendmsg(struct sock *sk)
+{
+ struct xdp_sock *xs = xdp_sk(sk);
+
+ if (unlikely(!(xs->dev->flags & IFF_UP)))
+ return -ENETDOWN;
+ if (unlikely(!xs->tx))
+ return -ENOBUFS;
+
+ return xs->zc ? xsk_zc_xmit(xs) : xsk_generic_xmit(sk);
+}
+
static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
{
bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
@@ -402,21 +412,18 @@ static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
if (unlikely(!xsk_is_bound(xs)))
return -ENXIO;
- if (unlikely(!(xs->dev->flags & IFF_UP)))
- return -ENETDOWN;
- if (unlikely(!xs->tx))
- return -ENOBUFS;
- if (need_wait)
+ if (unlikely(need_wait))
return -EOPNOTSUPP;
- return (xs->zc) ? xsk_zc_xmit(sk) : xsk_generic_xmit(sk, m, total_len);
+ return __xsk_sendmsg(sk);
}
static unsigned int xsk_poll(struct file *file, struct socket *sock,
struct poll_table_struct *wait)
{
unsigned int mask = datagram_poll(file, sock, wait);
- struct xdp_sock *xs = xdp_sk(sock->sk);
+ struct sock *sk = sock->sk;
+ struct xdp_sock *xs = xdp_sk(sk);
struct net_device *dev;
struct xdp_umem *umem;
@@ -426,9 +433,14 @@ static unsigned int xsk_poll(struct file *file, struct socket *sock,
dev = xs->dev;
umem = xs->umem;
- if (umem->need_wakeup)
- dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id,
- umem->need_wakeup);
+ if (umem->need_wakeup) {
+ if (dev->netdev_ops->ndo_xsk_wakeup)
+ dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id,
+ umem->need_wakeup);
+ else
+ /* Poll needs to drive Tx also in copy mode */
+ __xsk_sendmsg(sk);
+ }
if (xs->rx && !xskq_empty_desc(xs->rx))
mask |= POLLIN | POLLRDNORM;