[PATCH 5.15.y] net: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode

[PATCH 5.15.y] net: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode

[Miguel Gazquez (Schneider Electric)]

From: Victor Nogueira <victor@mojatatu.com>

[ Upstream commit 9cb36faedeafb9720ac236aeae2ea57091d90a09 ]

When u32_replace_hw_knode fails, we need to undo the tcf_bind_filter
operation done at u32_set_parms.

Fixes: d34e3e181395 ("net: cls_u32: Add support for skip-sw flag to tc u32 classifier.")
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Pedro Tammela <pctammela@mojatatu.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Miguel Gazquez (Schneider Electric) <miguel.gazquez@bootlin.com>
---
 net/sched/cls_u32.c | 38 +++++++++++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 23f9e2b5f3b6..b36eced10ff4 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -709,8 +709,23 @@ static const struct nla_policy u32_policy[TCA_U32_MAX + 1] = {
 	[TCA_U32_FLAGS]		= { .type = NLA_U32 },
 };
 
+static void u32_unbind_filter(struct tcf_proto *tp, struct tc_u_knode *n,
+			      struct nlattr **tb)
+{
+	if (tb[TCA_U32_CLASSID])
+		tcf_unbind_filter(tp, &n->res);
+}
+
+static void u32_bind_filter(struct tcf_proto *tp, struct tc_u_knode *n,
+			    unsigned long base, struct nlattr **tb)
+{
+	if (tb[TCA_U32_CLASSID]) {
+		n->res.classid = nla_get_u32(tb[TCA_U32_CLASSID]);
+		tcf_bind_filter(tp, &n->res, base);
+	}
+}
+
 static int u32_set_parms(struct net *net, struct tcf_proto *tp,
-			 unsigned long base,
 			 struct tc_u_knode *n, struct nlattr **tb,
 			 struct nlattr *est, u32 flags,
 			 struct netlink_ext_ack *extack)
@@ -756,10 +771,6 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp,
 		if (ht_old)
 			ht_old->refcnt--;
 	}
-	if (tb[TCA_U32_CLASSID]) {
-		n->res.classid = nla_get_u32(tb[TCA_U32_CLASSID]);
-		tcf_bind_filter(tp, &n->res, base);
-	}
 
 	if (ifindex >= 0)
 		n->ifindex = ifindex;
@@ -898,7 +909,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		if (!new)
 			return -ENOMEM;
 
-		err = u32_set_parms(net, tp, base, new, tb,
+		err = u32_set_parms(net, tp, new, tb,
 				    tca[TCA_RATE], flags, extack);
 
 		if (err) {
@@ -906,8 +917,12 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 			return err;
 		}
 
+		u32_bind_filter(tp, new, base, tb);
+
 		err = u32_replace_hw_knode(tp, new, flags, extack);
 		if (err) {
+			u32_unbind_filter(tp, new, tb);
+
 			__u32_destroy_key(new);
 			return err;
 		}
@@ -1108,15 +1123,18 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 	}
 #endif
 
-	err = u32_set_parms(net, tp, base, n, tb, tca[TCA_RATE], flags,
+	err = u32_set_parms(net, tp, n, tb, tca[TCA_RATE], flags,
 			    extack);
+
+	u32_bind_filter(tp, n, base, tb);
+
 	if (err == 0) {
 		struct tc_u_knode __rcu **ins;
 		struct tc_u_knode *pins;
 
 		err = u32_replace_hw_knode(tp, n, flags, extack);
 		if (err)
-			goto errhw;
+			goto errunbind;
 
 		if (!tc_in_hw(n->flags))
 			n->flags |= TCA_CLS_FLAGS_NOT_IN_HW;
@@ -1134,7 +1152,9 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		return 0;
 	}
 
-errhw:
+errunbind:
+	u32_unbind_filter(tp, n, tb);
+
 #ifdef CONFIG_CLS_U32_MARK
 	free_percpu(n->pcpu_success);
 #endif

---
base-commit: a051a4bf909f76f470ccb3761ee0cf6e2395616e
change-id: 20261005-cve-2023-53733-5-15-0994b6e82c3b

Best regards,
--  
Miguel Gazquez (Schneider Electric) <miguel.gazquez@bootlin.com>

Re: [PATCH 5.15.y] net: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode

[netdev-bot+sinfo]

Hi!

This is an automated message. This series looks like a fix, but its
commit messages seem to be missing some information:

 - How the issue was discovered, e.g. hit in production, hit during
   development, syzbot report, manual code inspection, LLM or static
   analysis tool scan.

 - Whether the issue was actually triggered, or is only theoretical
   (e.g. found by code inspection). If it was triggered please include
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Please do not repost the series just to address the above. Instead,
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