[PATCH 6.0 063/124] net: hsr: Fix potential use-after-free

Greg Kroah-Hartman
2022-12-05T19:26:47Z

From: YueHaibing <yuehaibing@huawei.com>

[ Upstream commit 7e177d32442b7ed08a9fa61b61724abc548cb248 ]

The skb is delivered to netif_rx() which may free it, after calling this,
dereferencing skb may trigger use-after-free.

Fixes: f421436a591d ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20221125075724.27912-1-yuehaibing@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/hsr/hsr_forward.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/hsr/hsr_forward.c b/net/hsr/hsr_forward.c
index a50429a62f74..56bb27d67a2e 100644
--- a/net/hsr/hsr_forward.c
+++ b/net/hsr/hsr_forward.c
@@ -351,17 +351,18 @@ static void hsr_deliver_master(struct sk_buff *skb, struct net_device *dev,
struct hsr_node *node_src)
{
bool was_multicast_frame;
- int res;
+ int res, recv_len;

was_multicast_frame = (skb->pkt_type == PACKET_MULTICAST);
hsr_addr_subst_source(node_src, skb);
skb_pull(skb, ETH_HLEN);
+ recv_len = skb->len;
res = netif_rx(skb);
if (res == NET_RX_DROP) {
dev->stats.rx_dropped++;
} else {
dev->stats.rx_packets++;
- dev->stats.rx_bytes += skb->len;
+ dev->stats.rx_bytes += recv_len;
if (was_multicast_frame)
dev->stats.multicast++;
}
--
2.35.1