From: valis <sec@valis.email> stable inclusion from stable-v5.10.190 commit b4256c99a7116c9514224847e8aaee2ecf110a0a category: bugfix issue: #I7ZATQ CVE: CVE-2023-4208 Signed-off-by: wanxiaoqing <wanxiaoqing@huawei.com> --------------------------------------- [ 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 <sec@valis.email> Reported-by: M A Ramdhan <ramdhan@starlabs.sg> Signed-off-by: valis <sec@valis.email> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Reviewed-by: Victor Nogueira <victor@mojatatu.com> Reviewed-by: Pedro Tammela <pctammela@mojatatu.com> Reviewed-by: M A Ramdhan <ramdhan@starlabs.sg> Link: https://lore.kernel.org/r/20230729123202.72406-2-jhs@mojatatu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: wanxiaoqing <wanxiaoqing@huawei.com> --- 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