From nobody Fri Jun 19 03:15:00 2026 Received: from azure-sdnproxy.icoremail.net (azure-sdnproxy.icoremail.net [13.76.78.106]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AA4DD1DF261; Sun, 14 Jun 2026 09:52:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.76.78.106 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781430772; cv=none; b=QF+rGOMgxdC6rC22XQcu2o1LCgktFJ8YdgQzjTOD49mMrazrwWHVCXI69/K6VSIGio2Su2LMQVyKcNwtwVLFYrryR+7tLbHkann44026ZsCFNpa3oFwGjvmp0S2+Hwaf3ravLa3AG2YRj0ptJOwfac+3KlAGVra4rLd+0hXpPqo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781430772; c=relaxed/simple; bh=7R2oMCXF7yh/HRb0bDxpLZMyKUeXkdWi85S30PhRtdU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=g6Yoj01LXoPGhKYPe8HNo97x++yqS45sk/+0cthHRe9lV1ZkLMd0R/+sH/mIm/63uV5nVfOgHEn7MxeFLH4XbEeIEqdLA7AbHizOWhqyI7ViibT/pWOA03PlshFLuDGSjMDjmAYTlUuFEJ9+fa5gnwgVHTYUVzEuia5dPiOOP4I= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mails.tsinghua.edu.cn; spf=pass smtp.mailfrom=mails.tsinghua.edu.cn; dkim=pass (1024-bit key) header.d=mails.tsinghua.edu.cn header.i=@mails.tsinghua.edu.cn header.b=I02DqksV; arc=none smtp.client-ip=13.76.78.106 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mails.tsinghua.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mails.tsinghua.edu.cn Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mails.tsinghua.edu.cn header.i=@mails.tsinghua.edu.cn header.b="I02DqksV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mails.tsinghua.edu.cn; s=dkim; h=Received:From:To:Cc:Subject: Date:Message-ID:MIME-Version:Content-Transfer-Encoding; bh=BfaiD FDk6S0iO2/wHu18Qvg1fwOvjyP5iFL/n/7N7JQ=; b=I02DqksVS+6/ByU2zNzw0 jJ26tatLyebxqHbEdTdjA5YyjiS/MEUS9HDmg52wSxMsAaRlhrebpznqAvZgZRoP nQiiUL9P2qiPOqcj60b84strOe5nFfk0pp0Oguq2EnFn5CfNb7LLWjlVkbydSRYc fUiT6QoWBmoMZDKuotlyCg= Received: from DESKTOP-35NLEVI (unknown [166.111.239.35]) by web3 (Coremail) with SMTP id ygQGZQC3A5HleS5qdZhtAg--.40976S2; Sun, 14 Jun 2026 17:52:37 +0800 (CST) From: Yizhou Zhao To: netdev@vger.kernel.org Cc: Yizhou Zhao , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Kees Cook , Kito Xu , linux-kernel@vger.kernel.org, Yuxiang Yang , Ao Wang , Xuewei Feng , Qi Li , Ke Xu , stable@vger.kernel.org Subject: [PATCH net] appletalk: Hold socket reference in atalk_rcv() Date: Sun, 14 Jun 2026 17:52:24 +0800 Message-ID: <20260614095226.1210-1-zhaoyz24@mails.tsinghua.edu.cn> X-Mailer: git-send-email 2.53.0.windows.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: ygQGZQC3A5HleS5qdZhtAg--.40976S2 X-Coremail-Antispam: 1UD129KBjvJXoW7tw48Jw1kurWDCF47Kr1xZrb_yoW8KF4kpF WrCF4jkFyUt34j9rn5Ja17Ar17CF4kKrW3G34rC342vFn8Wa4Fqr10vw4F9rZ0krZ5GFWj qrZ7GFWjyr1UZrDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUP014x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1lnxkEFVAIw20F6cxK64vIFxWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xv F2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r 4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I 648v4I1lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2AFwI0_Jw0_GFylc2xSY4AK67 AK6r4fMxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAF wI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc4 0Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AK xVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr 1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUjWxR3UU UUU== X-CM-SenderInfo: 52kd05r2suqzpdlo2hxwvl0wxkxdhvlgxou0/1tbiAQESAWot2C-jUAABsR Content-Type: text/plain; charset="utf-8" atalk_search_socket() walks the global atalk_sockets list while holding atalk_sockets_lock, but it returns the matching socket after dropping the lock without taking a reference. atalk_rcv() then passes that pointer to sock_queue_rcv_skb(). That leaves a race with close(). A concurrent atalk_release() can orphan the socket, remove it from atalk_sockets, and drop the final reference via atalk_destroy_socket(), freeing the socket before atalk_rcv() queues the incoming skb. On a KASAN-enabled kernel this can be reproduced by racing AppleTalk DDP delivery on loopback against close/rebind of the destination DGRAM socket: BUG: KASAN: slab-use-after-free in selinux_socket_sock_rcv_skb() sk_filter_trim_cap() sock_queue_rcv_skb_reason() atalk_rcv() snap_rcv() llc_rcv() Take a reference on the selected socket before dropping atalk_sockets_lock, and put it after sock_queue_rcv_skb() has finished. This keeps the socket alive for the receive path without changing socket lookup semantics. A malformed or racing receive still drops the skb on queueing failure as before. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reported-by: Yizhou Zhao Reported-by: Yuxiang Yang Reported-by: Ao Wang Reported-by: Xuewei Feng Reported-by: Qi Li Reported-by: Ke Xu Assisted-by: GLM:GLM-5.1 Signed-off-by: Yizhou Zhao --- net/appletalk/ddp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c index 30a6dc06291c..61ec5c569dc3 100644 --- a/net/appletalk/ddp.c +++ b/net/appletalk/ddp.c @@ -131,6 +131,8 @@ static struct sock *atalk_search_socket(struct sockaddr= _at *to, } s =3D def_socket; found: + if (s) + sock_hold(s); read_unlock_bh(&atalk_sockets_lock); return s; } @@ -1474,9 +1476,12 @@ static int atalk_rcv(struct sk_buff *skb, struct net= _device *dev, goto drop; =20 /* Queue packet (standard) */ - if (sock_queue_rcv_skb(sock, skb) < 0) + if (sock_queue_rcv_skb(sock, skb) < 0) { + sock_put(sock); goto drop; + } =20 + sock_put(sock); return NET_RX_SUCCESS; =20 drop: --=20 2.43.0