net: ethernet: SP7021: fix a use after free of skb->len

The netif_receive_skb() function frees "skb" so store skb->len before
it is freed.

Fixes: fd3040b9394c ("net: ethernet: Add driver for Sunplus SP7021")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YoUuy4iTjFAcSn03@kili
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/sunplus/spl2sw_int.c b/drivers/net/ethernet/sunplus/spl2sw_int.c
index 69b1e2e0271e678330e5616284a5851e8a54ed3a..a37c9a4c281f053bd8c327b7f5ed36157581976e 100644 (file)
--- a/drivers/net/ethernet/sunplus/spl2sw_int.c
+++ b/drivers/net/ethernet/sunplus/spl2sw_int.c
@@ -29,6 +29,7 @@ int spl2sw_rx_poll(struct napi_struct *napi, int budget)
        u32 mask;
        int port;
        u32 cmd;
+       u32 len;
 
        /* Process high-priority queue and then low-priority queue. */
        for (queue = 0; queue < RX_DESC_QUEUE_NUM; queue++) {
@@ -63,10 +64,11 @@ int spl2sw_rx_poll(struct napi_struct *napi, int budget)
                        skb_put(skb, pkg_len - 4); /* Minus FCS */
                        skb->ip_summed = CHECKSUM_NONE;
                        skb->protocol = eth_type_trans(skb, comm->ndev[port]);
+                       len = skb->len;
                        netif_receive_skb(skb);
 
                        stats->rx_packets++;
-                       stats->rx_bytes += skb->len;
+                       stats->rx_bytes += len;
 
                        /* Allocate a new skb for receiving. */
                        new_skb = netdev_alloc_skb(NULL, comm->rx_desc_buff_size);