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From:   Dongliang Mu <mudongliangabcd@gmail.com>
To:     alex.aring@gmail.com, stefan@datenfreihafen.org,
        davem@davemloft.net, kuba@kernel.org
Cc:     linux-wpan@vger.kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, Dongliang Mu <mudongliangabcd@gmail.com>,
        syzbot+b80c9959009a9325cdff@syzkaller.appspotmail.com
Subject: [PATCH v2] ieee802154: hwsim: Fix memory leak in hwsim_add_one
Date:   Wed, 16 Jun 2021 10:09:01 +0800
Message-Id: <20210616020901.2759466-1-mudongliangabcd@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

No matter from hwsim_remove or hwsim_del_radio_nl, hwsim_del fails to
remove the entry in the edges list. Take the example below, phy0, phy1
and e0 will be deleted, resulting in e1 not freed and accessed in the
future.

              hwsim_phys
                  |
    ------------------------------
    |                            |
phy0 (edges)                 phy1 (edges)
   ----> e1 (idx = 1)             ----> e0 (idx = 0)

Fix this by deleting and freeing all the entries in the edges list
between hwsim_edge_unsubscribe_me and list_del(&phy->list).

Reported-by: syzbot+b80c9959009a9325cdff@syzkaller.appspotmail.com
Fixes: 1c9f4a3fce77 ("ieee802154: hwsim: fix rcu handling")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
v1->v2: add rcu_read_lock for the deletion operation according to Pavel Skripkin

 drivers/net/ieee802154/mac802154_hwsim.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ieee802154/mac802154_hwsim.c b/drivers/net/ieee802154/mac802154_hwsim.c
index da9135231c07..cf659361a3fb 100644
--- a/drivers/net/ieee802154/mac802154_hwsim.c
+++ b/drivers/net/ieee802154/mac802154_hwsim.c
@@ -824,12 +824,17 @@ static int hwsim_add_one(struct genl_info *info, struct device *dev,
 static void hwsim_del(struct hwsim_phy *phy)
 {
 	struct hwsim_pib *pib;
+	struct hwsim_edge *e;
 
 	hwsim_edge_unsubscribe_me(phy);
 
 	list_del(&phy->list);
 
 	rcu_read_lock();
+	list_for_each_entry_rcu(e, &phy->edges, list) {
+		list_del_rcu(&e->list);
+		hwsim_free_edge(e);
+	}
 	pib = rcu_dereference(phy->pib);
 	rcu_read_unlock();
 
-- 
2.25.1