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authorZhengchao Shao <shaozhengchao@huawei.com>2023-07-10 17:40:53 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-08-23 17:52:32 +0200
commit2b05bf5dc437f7891dd409a3eaf5058459391c7a (patch)
tree27e0c9b7210785f222e53ec8e117e47edf3f757b /net
parent55ad2309205cc00c585344374c7472420e1b2c12 (diff)
downloadlinux-2b05bf5dc437f7891dd409a3eaf5058459391c7a.tar.gz
ip_vti: fix potential slab-use-after-free in decode_session6
[ Upstream commit 6018a266279b1a75143c7c0804dd08a5fc4c3e0b ]

When ip_vti device is set to the qdisc of the sfb type, the cb field
of the sent skb may be modified during enqueuing. Then,
slab-use-after-free may occur when ip_vti device sends IPv6 packets.
As commit f855691975bb ("xfrm6: Fix the nexthdr offset in
_decode_session6.") showed, xfrm_decode_session was originally intended
only for the receive path. IP6CB(skb)->nhoff is not set during
transmission. Therefore, set the cb field in the skb to 0 before
sending packets.

Fixes: f855691975bb ("xfrm6: Fix the nexthdr offset in _decode_session6.")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/ip_vti.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index 8c2bd1d9ddce..615c1dcf3a28 100644
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -287,12 +287,12 @@ static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	switch (skb->protocol) {
 	case htons(ETH_P_IP):
-		xfrm_decode_session(skb, &fl, AF_INET);
 		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
+		xfrm_decode_session(skb, &fl, AF_INET);
 		break;
 	case htons(ETH_P_IPV6):
-		xfrm_decode_session(skb, &fl, AF_INET6);
 		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
+		xfrm_decode_session(skb, &fl, AF_INET6);
 		break;
 	default:
 		goto tx_err;