[openwrt/openwrt] kernel: fix crashes in bridge offload code

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch openwrt-22.03:
https://git.openwrt.org/8e9eaef70a444348fd8f90fbe26a07e1ad564972

commit 8e9eaef70a444348fd8f90fbe26a07e1ad564972
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Tue May 31 14:01:21 2022 +0200

    kernel: fix crashes in bridge offload code
    
    - fix an issues when accessing the port pointer of an expired/invalid fdb entry
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
    (cherry picked from commit 38a5b593ef9e94deedefb627f1952b3bb881df56)
---
 target/linux/generic/hack-5.10/600-bridge_offload.patch | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/target/linux/generic/hack-5.10/600-bridge_offload.patch b/target/linux/generic/hack-5.10/600-bridge_offload.patch
index 586353816c..7e1b852bf3 100644
--- a/target/linux/generic/hack-5.10/600-bridge_offload.patch
+++ b/target/linux/generic/hack-5.10/600-bridge_offload.patch
@@ -434,13 +434,13 @@
 +	vg = nbp_vlan_group_rcu(inp);
 +	vlan = cb->input_vlan_present ? cb->input_vlan_tag : br_get_pvid(vg);
 +	fdb_in = br_fdb_find_rcu(p->br, eth_hdr(skb)->h_source, vlan);
-+	if (!fdb_in)
++	if (!fdb_in || !fdb_in->dst)
 +		goto out;
 +
 +	vg = nbp_vlan_group_rcu(p);
 +	vlan = skb_vlan_tag_present(skb) ? skb_vlan_tag_get_id(skb) : br_get_pvid(vg);
 +	fdb_out = br_fdb_find_rcu(p->br, eth_hdr(skb)->h_dest, vlan);
-+	if (!fdb_out)
++	if (!fdb_out || !fdb_out->dst)
 +		goto out;
 +
 +	br_offload_prepare_key(p, &key, skb);
@@ -450,7 +450,7 @@
 +#endif
 +
 +	flow = kmem_cache_alloc(offload_cache, GFP_ATOMIC);
-+	flow->port = fdb_in->dst;
++	flow->port = inp;
 +	memcpy(&flow->key, &key, sizeof(key));
 +
 +#ifdef CONFIG_BRIDGE_VLAN_FILTERING
@@ -465,7 +465,7 @@
 +	spin_lock_bh(&offload_lock);
 +	if (!o->enabled ||
 +	    atomic_read(&p->offload.rht.nelems) >= p->br->offload_cache_size ||
-+	    rhashtable_insert_fast(&flow->port->offload.rht, &flow->node, flow_params)) {
++	    rhashtable_insert_fast(&inp->offload.rht, &flow->node, flow_params)) {
 +		kmem_cache_free(offload_cache, flow);
 +		goto out_unlock;
 +	}
@@ -511,8 +511,8 @@
 +#ifdef CONFIG_BRIDGE_VLAN_FILTERING
 +		cb->input_vlan_present = key.vlan_present != 0;
 +		cb->input_vlan_tag = key.vlan_tag;
-+		cb->input_ifindex = p->dev->ifindex;
 +#endif
++		cb->input_ifindex = p->dev->ifindex;
 +		goto out;
 +	}
 +