From 9040adc38cf6bfbb77034d558ac2c52f70d840ac Mon Sep 17 00:00:00 2001 From: Zhang Shurong Date: Fri, 23 Jun 2023 13:39:35 +0800 Subject: [PATCH] firewire: net: fix use after free in fwnet_finish_incoming_packet() [ Upstream commit 3ff256751a2853e1ffaa36958ff933ccc98c6cb5 ] The netif_rx() function frees the skb so we can't dereference it to save the skb->len. Signed-off-by: Zhang Shurong Link: https://lore.kernel.org/r/tencent_3B3D24B66ED66A6BB73CC0E63C6A14E45109@qq.com Signed-off-by: Takashi Sakamoto Signed-off-by: Sasha Levin --- drivers/firewire/net.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c index af22be8..a53eace 100644 --- a/drivers/firewire/net.c +++ b/drivers/firewire/net.c @@ -479,7 +479,7 @@ static int fwnet_finish_incoming_packet(struct net_device *net, struct sk_buff *skb, u16 source_node_id, bool is_broadcast, u16 ether_type) { - int status; + int status, len; switch (ether_type) { case ETH_P_ARP: @@ -533,13 +533,15 @@ static int fwnet_finish_incoming_packet(struct net_device *net, } skb->protocol = protocol; } + + len = skb->len; status = netif_rx(skb); if (status == NET_RX_DROP) { net->stats.rx_errors++; net->stats.rx_dropped++; } else { net->stats.rx_packets++; - net->stats.rx_bytes += skb->len; + net->stats.rx_bytes += len; } return 0; -- 2.7.4