From: valis Date: Sat, 29 Jul 2023 12:32:01 +0000 (-0400) Subject: net/sched: cls_fw: No longer copy tcf_result on update to avoid use-after-free X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=76e42ae831991c828cffa8c37736ebfb831ad5ec;p=linux.git net/sched: cls_fw: No longer copy tcf_result on update to avoid use-after-free 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 --- diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c index 8641f80593179..c49d6af0e0480 100644 --- a/net/sched/cls_fw.c +++ b/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;