netdev - [PATCH net 5/5] net: sched: cls_flower: Undo tcf_bind_filter if fl_set

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Date: Tue,  4 Jul 2023 12:14:56 -0300
From: Victor Nogueira <victor@...atatu.com>
To: netdev@...r.kernel.org
Cc: jhs@...atatu.com,
	xiyou.wangcong@...il.com,
	jiri@...nulli.us,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	pctammela@...atatu.com,
	kernel@...atatu.com
Subject: [PATCH net 5/5] net: sched: cls_flower: Undo tcf_bind_filter if fl_set_key fails

if TCA_FLOWER_CLASSID is specified in the netlink message, the code will
call tcf_bind_filter. However, if any error occurs after that, the code
should undo this by calling tcf_unbind_filter.

When checking for TCA_FLOWER_CLASSID attribute, the code is calling for
tcf_bind_fitler.

Fixes: 77b9900ef53a ("tc: introduce Flower classifier")

Signed-off-by: Victor Nogueira <victor@...atatu.com>
Acked-by: Jamal Hadi Salim <jhs@...atatu.com>
Reviewed-by: Pedro Tammela <pctammela@...atatu.com>
---
 net/sched/cls_flower.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 56065cc5a661..644b0097e6ae 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -2169,7 +2169,7 @@ static int fl_set_parms(struct net *net, struct tcf_proto *tp,
 			struct nlattr *est,
 			struct fl_flow_tmplt *tmplt,
 			u32 flags, u32 fl_flags,
-			struct netlink_ext_ack *extack)
+			bool *bound_to_filter, struct netlink_ext_ack *extack)
 {
 	int err;
 
@@ -2185,18 +2185,20 @@ static int fl_set_parms(struct net *net, struct tcf_proto *tp,
 		tcf_bind_filter(tp, &f->res, base);
 		if (flags & TCA_ACT_FLAGS_NO_RTNL)
 			rtnl_unlock();
+		*bound_to_filter = true;
 	}
 
 	err = fl_set_key(net, tb, &f->key, &mask->key, extack);
 	if (err)
-		return err;
+		goto unbind_filter;
 
 	fl_mask_update_range(mask);
 	fl_set_masked_key(&f->mkey, &f->key, mask);
 
 	if (!fl_mask_fits_tmplt(tmplt, mask)) {
 		NL_SET_ERR_MSG_MOD(extack, "Mask does not fit the template");
-		return -EINVAL;
+		err = -EINVAL;
+		goto unbind_filter;
 	}
 
 	/* Enable tc skb extension if filter matches on data extracted from
@@ -2208,6 +2210,17 @@ static int fl_set_parms(struct net *net, struct tcf_proto *tp,
 	}
 
 	return 0;
+
+unbind_filter:
+	if (*bound_to_filter) {
+		if (flags & TCA_ACT_FLAGS_NO_RTNL)
+			rtnl_lock();
+		tcf_unbind_filter(tp, &f->res);
+		if (flags & TCA_ACT_FLAGS_NO_RTNL)
+			rtnl_unlock();
+		*bound_to_filter = false;
+	}
+	return err;
 }
 
 static int fl_ht_insert_unique(struct cls_fl_filter *fnew,
@@ -2241,6 +2254,7 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
 	struct cls_fl_head *head = fl_head_dereference(tp);
 	bool rtnl_held = !(flags & TCA_ACT_FLAGS_NO_RTNL);
 	struct cls_fl_filter *fold = *arg;
+	bool bound_to_filter = false;
 	struct cls_fl_filter *fnew;
 	struct fl_flow_mask *mask;
 	struct nlattr **tb;
@@ -2327,7 +2341,7 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
 
 	err = fl_set_parms(net, tp, fnew, mask, base, tb, tca[TCA_RATE],
 			   tp->chain->tmplt_priv, flags, fnew->flags,
-			   extack);
+			   &bound_to_filter, extack);
 	if (err)
 		goto errout_idr;
 
@@ -2425,6 +2439,13 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
 errout_mask:
 	fl_mask_put(head, fnew->mask);
 errout_idr:
+	if (bound_to_filter) {
+		if (flags & TCA_ACT_FLAGS_NO_RTNL)
+			rtnl_lock();
+		tcf_unbind_filter(tp, &fnew->res);
+		if (flags & TCA_ACT_FLAGS_NO_RTNL)
+			rtnl_unlock();
+	}
 	if (!fold)
 		idr_remove(&head->handle_idr, fnew->handle);
 	__fl_put(fnew);
-- 
2.25.1