Revert "xsk: Support redirect to any socket bound to the same umem"

This reverts commit 2863d665ea41282379f108e4da6c8a2366ba66db.

This patch introduced a potential kernel crash when multiple napi instances
redirect to the same AF_XDP socket. By removing the queue_index check, it is
possible for multiple napi instances to access the Rx ring at the same time,
which will result in a corrupted ring state which can lead to a crash when
flushing the rings in __xsk_flush(). This can happen when the linked list of
sockets to flush gets corrupted by concurrent accesses. A quick and small fix
is not possible, so let us revert this for now.

Reported-by: Yuval El-Hanany <YuvalE@radware.com>
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/xdp-newbies/8100DBDC-0B7C-49DB-9995-6027F6E63147@radware.com
Link: https://lore.kernel.org/bpf/20240604122927.29080-2-magnus.karlsson@gmail.com

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 727aa20be4bde8dc63a544a44a5cdeb19cac7dcb..7d1c0986f9bb354aa5a562f3edc72e54837b8ac5 100644 (file)
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -313,13 +313,10 @@ static bool xsk_is_bound(struct xdp_sock *xs)
 
 static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
 {
-       struct net_device *dev = xdp->rxq->dev;
-       u32 qid = xdp->rxq->queue_index;
-
        if (!xsk_is_bound(xs))
                return -ENXIO;
 
-       if (!dev->_rx[qid].pool || xs->umem != dev->_rx[qid].pool->umem)
+       if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
                return -EINVAL;
 
        if (len > xsk_pool_get_rx_frame_size(xs->pool) && !xs->sg) {