net/sched: cls_fw: Fix improper refcount update leads to use-after-free

mainline inclusion
from mainline-v6.4
commit 0323bce598eea038714f941ce2b22541c46d488f
category: bugfix
bugzilla: 189032, https://gitee.com/src-openeuler/kernel/issues/I7N3N3
CVE: CVE-2023-3776

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0323bce598eea038714f941ce2b22541c46d488f

---------------------------

In the event of a failure in tcf_change_indev(), fw_set_parms() will
immediately return an error after incrementing or decrementing
reference counter in tcf_bind_filter().  If attacker can control
reference counter to zero and make reference freed, leading to
use after free.

In order to prevent this, move the point of possible failure above the
point where the TC_FW_CLASSID is handled.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reported-by: NM A Ramdhan <ramdhan@starlabs.sg>
Signed-off-by: NM A Ramdhan <ramdhan@starlabs.sg>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: NPedro Tammela <pctammela@mojatatu.com>
Message-ID: <20230705161530.52003-1-ramdhan@starlabs.sg>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Conflict:
	net/sched/cls_fw.c
Signed-off-by: Ndongchenchen <dongchenchen2@huawei.com>

net/sched/cls_fw.c

@@ -221,11 +221,6 @@ static int fw_set_parms(struct net *net, struct tcf_proto *tp,
 	if (err < 0)
 		return err;
 
-	if (tb[TCA_FW_CLASSID]) {
-		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
-		tcf_bind_filter(tp, &f->res, base);
-	}
-
 #ifdef CONFIG_NET_CLS_IND
 	if (tb[TCA_FW_INDEV]) {
 		int ret;
@@ -244,6 +239,11 @@ static int fw_set_parms(struct net *net, struct tcf_proto *tp,
 	} else if (head->mask != 0xFFFFFFFF)
 		return err;
 
+	if (tb[TCA_FW_CLASSID]) {
+		f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]);
+		tcf_bind_filter(tp, &f->res, base);
+	}
+
 	return 0;
 }