From faa91b839b09b15d6f9655fc866fa433bb65454c Mon Sep 17 00:00:00 2001
From: Tirthendu Sarkar <tirthendu.sarkar@intel.com>
Date: Wed, 19 Jul 2023 15:24:01 +0200
Subject: [PATCH] xsk: move xdp_buff's data length check to xsk_rcv_check
If the data in xdp_buff exceeds the xsk frame length, the packet needs
to be dropped. This check is currently being done in __xsk_rcv(). Move
the described logic to xsk_rcv_check() so that such a xdp_buff will
only be dropped if the application does not support multi-buffer
(absence of XDP_USE_SG bind flag). This is applicable for all cases:
copy mode, zero copy mode as well as skb mode.
Signed-off-by: Tirthendu Sarkar <tirthendu.sarkar@intel.com>
Link: https://lore.kernel.org/r/20230719132421.584801-5-maciej.fijalkowski@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
net/xdp/xsk.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 029a092582da4..a968ac506f4a1 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -177,18 +177,11 @@ static void xsk_copy_xdp(struct xdp_buff *to, struct xdp_buff *from, u32 len)
memcpy(to_buf, from_buf, len + metalen);
}
-static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
+static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
{
struct xdp_buff_xsk *xskb;
struct xdp_buff *xsk_xdp;
int err;
- u32 len;
-
- len = xdp->data_end - xdp->data;
- if (len > xsk_pool_get_rx_frame_size(xs->pool)) {
- xs->rx_dropped++;
- return -ENOSPC;
- }
xsk_xdp = xsk_buff_alloc(xs->pool);
if (!xsk_xdp) {
@@ -224,7 +217,7 @@ static bool xsk_is_bound(struct xdp_sock *xs)
return false;
}
-static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp)
+static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
{
if (!xsk_is_bound(xs))
return -ENXIO;
@@ -232,6 +225,11 @@ static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp)
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->rx_dropped++;
+ return -ENOSPC;
+ }
+
sk_mark_napi_id_once_xdp(&xs->sk, xdp);
return 0;
}
@@ -245,12 +243,13 @@ static void xsk_flush(struct xdp_sock *xs)
int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
{
+ u32 len = xdp_get_buff_len(xdp);
int err;
spin_lock_bh(&xs->rx_lock);
- err = xsk_rcv_check(xs, xdp);
+ err = xsk_rcv_check(xs, xdp, len);
if (!err) {
- err = __xsk_rcv(xs, xdp);
+ err = __xsk_rcv(xs, xdp, len);
xsk_flush(xs);
}
spin_unlock_bh(&xs->rx_lock);
@@ -259,10 +258,10 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
{
+ u32 len = xdp_get_buff_len(xdp);
int err;
- u32 len;
- err = xsk_rcv_check(xs, xdp);
+ err = xsk_rcv_check(xs, xdp, len);
if (err)
return err;
@@ -271,7 +270,7 @@ static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
return xsk_rcv_zc(xs, xdp, len);
}
- err = __xsk_rcv(xs, xdp);
+ err = __xsk_rcv(xs, xdp, len);
if (!err)
xdp_return_buff(xdp);
return err;