From: valis <sec@valis.email>
Commit 76e42ae831991c828cffa8c37736ebfb831ad5ec upstream.
[ Fixed small conflict as 'fnew->ifindex' assignment is not protected by
CONFIG_NET_CLS_IND on upstream since a51486266c3 ]
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 <sec@valis.email>
Reported-by: Bing-Jhong Billy Jheng <billy@xxxxxxxxxxx>
Signed-off-by: valis <sec@valis.email>
Signed-off-by: Jamal Hadi Salim <jhs@xxxxxxxxxxxx>
Reviewed-by: Victor Nogueira <victor@xxxxxxxxxxxx>
Reviewed-by: Pedro Tammela <pctammela@xxxxxxxxxxxx>
Reviewed-by: M A Ramdhan <ramdhan@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230729123202.72406-3-jhs@xxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Luiz Capitulino <luizcap@xxxxxxxxxx>
---
net/sched/cls_fw.c | 1 -
1 file changed, 1 deletion(-)
Valis, Greg,
I noticed that 4.14 is missing this fix while we backported all three fixes
from this series to all stable kernels:
https://lore.kernel.org/all/20230729123202.72406-1-jhs@xxxxxxxxxxxx
Is there a reason to have skipped 4.14 for this fix? It seems we need it.
This is only compiled-tested though, would be good to have a confirmation
from Valis that the issue is present on 4.14 before applying.
- Luiz
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 */
--
2.40.1
