From: valis
stable inclusion
from stable-v5.10.190
commit b4256c99a7116c9514224847e8aaee2ecf110a0a
category: bugfix
issue: #I7ZATQ
CVE: CVE-2023-4208
Signed-off-by: wanxiaoqing
---------------------------------------
[ Upstream commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81 ]
When u32_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: de5df63228fc ("net: sched: cls_u32 changes to knode must appear atomic to readers")
Reported-by: valis
Reported-by: M A Ramdhan
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/20230729123202.72406-2-jhs@mojatatu.com
Signed-off-by: Jakub Kicinski
Signed-off-by: Sasha Levin
Signed-off-by: wanxiaoqing
---
net/sched/cls_u32.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 1ac8ff445a6d..b8c44ead0c16 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -812,7 +812,6 @@ 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);
--
2.25.1
