From 530a85ea747965b7c275fa44a364916e0ec2efaa Mon Sep 17 00:00:00 2001 From: valis Date: Sat, 29 Jul 2023 08:32:01 -0400 Subject: [PATCH] net/sched: cls_fw: No longer copy tcf_result on update to avoid use-after-free commit 76e42ae831991c828cffa8c37736ebfb831ad5ec upstream. When fw_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. 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. Fix this by no longer copying the tcf_result struct from the old filter. Fixes: e35a8ee5993b ("net: sched: fw use RCU") Reported-by: valis Reported-by: Bing-Jhong Billy Jheng Signed-off-by: valis Signed-off-by: Jamal Hadi Salim Reviewed-by: Victor Nogueira Reviewed-by: Pedro Tammela Reviewed-by: M A Ramdhan Link: https://lore.kernel.org/r/20230729123202.72406-3-jhs@mojatatu.com Signed-off-by: Jakub Kicinski [ Fixed small conflict as 'fnew->ifindex' assignment is not protected by CONFIG_NET_CLS_IND on upstream since a51486266c3 ] Signed-off-by: Luiz Capitulino Signed-off-by: Greg Kroah-Hartman --- net/sched/cls_fw.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c index e63f9c2e37e5..7b04b315b2bd 100644 --- a/net/sched/cls_fw.c +++ b/net/sched/cls_fw.c @@ -281,7 +281,6 @@ static int fw_change(struct net *net, struct sk_buff *in_skb, return -ENOBUFS; fnew->id = f->id; - fnew->res = f->res; #ifdef CONFIG_NET_CLS_IND fnew->ifindex = f->ifindex; #endif /* CONFIG_NET_CLS_IND */