linux-kernel - [PATH wpan v3] ieee802154: hwsim: Fix possible memory leaks

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Message-Id: <20230409022048.61223-1-chenaotian2@163.com>
Date:   Sun,  9 Apr 2023 10:20:48 +0800
From:   Chen Aotian <chenaotian2@....com>
To:     alex.aring@...il.com
Cc:     stefan@...enfreihafen.org, miquel.raynal@...tlin.com,
        davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        pabeni@...hat.com, linux-wpan@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org, Chen Aotian <chenaotian2@....com>,
        Alexander Aring <aahringo@...hat.com>
Subject: [PATH wpan v3] ieee802154: hwsim: Fix possible memory leaks

After replacing e->info, it is necessary to free the old einfo.

Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb")
Reviewed-by: Miquel Raynal <miquel.raynal@...tlin.com>
Reviewed-by: Alexander Aring <aahringo@...hat.com>
Signed-off-by: Chen Aotian <chenaotian2@....com>
---

V2 -> V3:
* lock_is_held() => lockdep_is_held().(thanks for Alexander)

V1 -> V2:
* Using rcu_replace_pointer() is better then rcu_dereference()
  and rcu_assign_pointer().

 drivers/net/ieee802154/mac802154_hwsim.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ieee802154/mac802154_hwsim.c b/drivers/net/ieee802154/mac802154_hwsim.c
index 8445c2189..31cba9aa7 100644
--- a/drivers/net/ieee802154/mac802154_hwsim.c
+++ b/drivers/net/ieee802154/mac802154_hwsim.c
@@ -685,7 +685,7 @@ static int hwsim_del_edge_nl(struct sk_buff *msg, struct genl_info *info)
 static int hwsim_set_edge_lqi(struct sk_buff *msg, struct genl_info *info)
 {
 	struct nlattr *edge_attrs[MAC802154_HWSIM_EDGE_ATTR_MAX + 1];
-	struct hwsim_edge_info *einfo;
+	struct hwsim_edge_info *einfo, *einfo_old;
 	struct hwsim_phy *phy_v0;
 	struct hwsim_edge *e;
 	u32 v0, v1;
@@ -723,8 +723,10 @@ static int hwsim_set_edge_lqi(struct sk_buff *msg, struct genl_info *info)
 	list_for_each_entry_rcu(e, &phy_v0->edges, list) {
 		if (e->endpoint->idx == v1) {
 			einfo->lqi = lqi;
-			rcu_assign_pointer(e->info, einfo);
+			einfo_old = rcu_replace_pointer(e->info, einfo,
+							lockdep_is_held(&hwsim_phys_lock));
 			rcu_read_unlock();
+			kfree_rcu(einfo_old, rcu);
 			mutex_unlock(&hwsim_phys_lock);
 			return 0;
 		}
-- 
2.25.1