Merge branch 'net-sched-bind-logic-fixes-for-cls_fw-cls_u32-and-cls_r…

…oute'

valis says:

====================
net/sched Bind logic fixes for cls_fw, cls_u32 and cls_route

Three classifiers (cls_fw, cls_u32 and cls_route) always copy
tcf_result struct into the new instance of the filter on update.

This causes a problem when updating a filter bound to a class,
as tcf_unbind_filter() is always called on the old instance in the
success path, decreasing filter_cnt of the still referenced class
and allowing it to be deleted, leading to a use-after-free.

This patch set fixes this issue in all affected classifiers by no longer
copying the tcf_result struct from the old filter.
====================

Link: https://lore.kernel.org/r/20230729123202.72406-1-jhs@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/sched/cls_fw.c

@@ -267,7 +267,6 @@ static int fw_change(struct net *net, struct sk_buff *in_skb,
 			return -ENOBUFS;
 
 		fnew->id = f->id;
-		fnew->res = f->res;
 		fnew->ifindex = f->ifindex;
 		fnew->tp = f->tp;
 

net/sched/cls_route.c

@@ -513,7 +513,6 @@ static int route4_change(struct net *net, struct sk_buff *in_skb,
 	if (fold) {
 		f->id = fold->id;
 		f->iif = fold->iif;
-		f->res = fold->res;
 		f->handle = fold->handle;
 
 		f->tp = fold->tp;

net/sched/cls_u32.c

@@ -826,7 +826,6 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp,
 
 	new->ifindex = n->ifindex;
 	new->fshift = n->fshift;
-	new->res = n->res;
 	new->flags = n->flags;
 	RCU_INIT_POINTER(new->ht_down, ht);