Patch "netfilter: flowtable: validate vlan header" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    netfilter: flowtable: validate vlan header

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     netfilter-flowtable-validate-vlan-header.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 012b16bb9ae8f2e096bc8e2beea85b34ad3ebb4c
Author: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Date:   Tue Aug 13 12:39:46 2024 +0200

    netfilter: flowtable: validate vlan header
    
    [ Upstream commit 6ea14ccb60c8ab829349979b22b58a941ec4a3ee ]
    
    Ensure there is sufficient room to access the protocol field of the
    VLAN header, validate it once before the flowtable lookup.
    
    =====================================================
    BUG: KMSAN: uninit-value in nf_flow_offload_inet_hook+0x45a/0x5f0 net/netfilter/nf_flow_table_inet.c:32
     nf_flow_offload_inet_hook+0x45a/0x5f0 net/netfilter/nf_flow_table_inet.c:32
     nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
     nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626
     nf_hook_ingress include/linux/netfilter_netdev.h:34 [inline]
     nf_ingress net/core/dev.c:5440 [inline]
    
    Fixes: 4cd91f7c290f ("netfilter: flowtable: add vlan support")
    Reported-by: syzbot+8407d9bb88cd4c6bf61a@xxxxxxxxxxxxxxxxxxxxxxxxx
    Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/netfilter/nf_flow_table_inet.c b/net/netfilter/nf_flow_table_inet.c
index 6eef15648b7b0..b0f1991719324 100644
--- a/net/netfilter/nf_flow_table_inet.c
+++ b/net/netfilter/nf_flow_table_inet.c
@@ -17,6 +17,9 @@ nf_flow_offload_inet_hook(void *priv, struct sk_buff *skb,
 
 	switch (skb->protocol) {
 	case htons(ETH_P_8021Q):
+		if (!pskb_may_pull(skb, skb_mac_offset(skb) + sizeof(*veth)))
+			return NF_ACCEPT;
+
 		veth = (struct vlan_ethhdr *)skb_mac_header(skb);
 		proto = veth->h_vlan_encapsulated_proto;
 		break;
diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index 5383bed3d3e00..846fa2ad7c858 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -281,6 +281,9 @@ static bool nf_flow_skb_encap_protocol(struct sk_buff *skb, __be16 proto,
 
 	switch (skb->protocol) {
 	case htons(ETH_P_8021Q):
+		if (!pskb_may_pull(skb, skb_mac_offset(skb) + sizeof(*veth)))
+			return false;
+
 		veth = (struct vlan_ethhdr *)skb_mac_header(skb);
 		if (veth->h_vlan_encapsulated_proto == proto) {
 			*offset += VLAN_HLEN;