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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , b.a.t.m.a.n@lists.open-mesh.org, Sven Eckelmann , stable@vger.kernel.org, Simon Wunderlich Subject: [PATCH net 05/10] batman-adv: fix skb leak when hard_iface is being released Date: Mon, 26 Oct 2026 09:53:04 +0100 Message-ID: <20261026085309.1074911-6-sw@simonwunderlich.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261026085309.1074911-1-sw@simonwunderlich.de> References: <20261026085309.1074911-1-sw@simonwunderlich.de> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Sven Eckelmann batadv_batman_skb_recv() owns the skb it is given. When the hard_iface refcount already dropped to zero, the function jumped to err_out, which only returned NET_RX_DROP and skipped the kfree_skb() under err_free. To avoid a leak, free the skb before returning in this case. Cc: stable@vger.kernel.org Fixes: 4fe56e60ac1b ("batman-adv: Check hard_iface refcnt when receiving skb") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/main.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c index 6c54a8d4be3ec..ced76942f33c5 100644 --- a/net/batman-adv/main.c +++ b/net/batman-adv/main.c @@ -484,8 +484,10 @@ int batadv_batman_skb_recv(struct sk_buff *skb, struct net_device *dev, * shut down otherwise the packet may trigger de-reference errors * further down in the receive path. */ - if (!kref_get_unless_zero(&hard_iface->refcount)) - goto err_out; + if (!kref_get_unless_zero(&hard_iface->refcount)) { + kfree_skb(skb); + return NET_RX_DROP; + } skb = skb_share_check(skb, GFP_ATOMIC); @@ -541,7 +543,6 @@ int batadv_batman_skb_recv(struct sk_buff *skb, struct net_device *dev, kfree_skb(skb); err_put: batadv_hardif_put(hard_iface); -err_out: return NET_RX_DROP; } -- 2.47.3