From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f46.google.com (mail-pj1-f46.google.com [209.85.216.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6B16A3E44ED for ; Fri, 18 Sep 2026 03:39:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789702776; cv=none; b=PXDo+VlXeOfNRmuulKKgiojIja2f1ev5qXAjhLEiDIcKUGa0AZsp/7Saj6Fvnl6mGqgvCbE06Y1sqRg2NuNFJj4JBnTEm3QBL0SzE0rMASUhDzEj+dRGEeRyvUh3qSQPH2NpJltZ9OS7XePK7xCug8/lts1DbRagU1lXGjcEWVo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789702776; c=relaxed/simple; bh=5DGBMHNqKO8hBWMRpZeiWO/8gLuazINjem6KokRy5sc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RwbIrngpd3Vau9AqPuEfEAUNdUYlFr0Oys7g7+BZ/xXffaCsmHidL8OGv33ifPYPR4HirbLjaWTsEWI5qcCfELcNCvGx/aMOe9vu//2miFlg7y9FQhdk55SmeO4Mh4E+74OinfcGQj+xiPIxCqUQjb3KtZUR00NHLXT3N9rdKA4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=UF4yTWNt; arc=none smtp.client-ip=209.85.216.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UF4yTWNt" Received: by mail-pj1-f46.google.com with SMTP id 98e67ed59e1d1-39647184c73so1234160a91.1 for ; Thu, 17 Sep 2026 20:39:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1789702774; x=1790307574; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=ILawRzLN/r3LsyBAHOfYBFFSxWw7SDBmyvoLxd7dlsc=; b=UF4yTWNtwKOCJGS79JemdwBC8mV87RSI1yYo50Km4C33BFC6mxqCfgH2FAAkSfYuIj uiULQekeWTFx1nJauvs27K1+dXsQonjayu6HIo/RgKAJ6HJNRWxz+NrflhI2Z3lkOlwz vtbKhcnsIUki2HDkYp9XX8Ier652baqPK1LRdjit1bsAmfzgaILSLfYgJWRKqqrpGoMo 0vc7zI3PDddAr6P4kZmGnLTXBAARF7eg+QIxf9EG/2ionkTsOpZCwYxaXrSw+PhtLUKP z1/1RBoKt+rL8aFv5mDNRCN2VqlX5+W13iR/3wz4clkQIp+voqvectVN2sb27t2TEnLR wmPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789702774; x=1790307574; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=ILawRzLN/r3LsyBAHOfYBFFSxWw7SDBmyvoLxd7dlsc=; b=ZOMhYN5kJDxZQYp/rhY/F43w8Qi3yf5gQTt4xGQ0TkUDJHdzOnK17bkXZjmv1hs2Jw OM0HNE+DummHwwHLRaOq+HrekKdb9y/4wfETYptqVoSIgxjdob5jwSnBvNGStpo/lvI5 xNMqIjWW7H55TLJIvn1QLcVlu+VVSgDiSwOAvv1+jAs93kt60sVz2lhn2NetJA5EaHfX s+kvILpDLjLv2qzTjwabu7nz8ITlc74D5lWZ2nynf3qThCHteucE3tG/f14017Xgh9Qk kLSeiif0sKXYFhx+o8wn1ZppA2Wj9ZOsWLMBIwjkoxiovVq1U3v6slGegguq8KRlhyDX iHPg== X-Forwarded-Encrypted: i=1; AKwUvBy9aFSyV1IrLpyJ8MgweQKawN9pVyf0b8Fgvx1DCXvNnZIYs5sCZxPSZgjbnxJt3cIh+Rg1LApSTCzUReo=@lists.linux.dev X-Gm-Message-State: AFuF++kQ7yhPSapmWZwHtOmGhVvpmzVyc3dpkNtowizc3ydJNGe0YxCC ztN/OHa8SdMd7a6j/d5LNc3lmQ9lCPrdavJHhl8Smn9i+SJnxo+rpuT6 X-Gm-Gg: AYBFou1fG0DtQCODjq6Lb1JnJ8FQ5qkKW//bi1jnTwro/nhD00zUz5XhBIwuz2Udmn6 0OT4b8bLmPKKcKEctvwDPflKt+JuJQ98V9X8BYQxyFa4ejjHYhnI8gS34VgeFCq3ts6tIUm75U9 kDnHnh99mghT/pR3JSlPb1Wlj6RuNxlzJxQjQF7Y5sgVfrYE0tDddZaY8T6ILq3XIfrm8E+Umyq /ec4V4kJ/1rrigjwLBlVUuoY125U4EnLO+3SSPZjM9sCJXOBfUhnb7kPJcuwF4lUczcaNk6BqPf 87OXC22TTHiBXZ1ZCBrTXZzcrOCbYuEELWQU3+vS6D3ibuz6jvPOGVq0TSzBFZrvWWvp+e6RvtH YKAxP7UZaivca0b4vAsUj0SjQxjVuUe8GPBQxCsEv34CiHZrOwdblwv1/NZsUcrLRgWe2XIdU+r OD0/Hr5jLTF2OCWBfye6c4ev/ycwE4bTCNh/5Izt+9Xn2qbJO8+vtk2/Kn4hoc7iPuUS/ym6ccm xZ1zvNQi0BipNupLdZOgcPhHQ+d7y3ONGSiLcI= X-Received: by 2002:a17:90b:4b11:b0:39e:4c97:ce0a with SMTP id 98e67ed59e1d1-39e4c97ceebmr3098526a91.43.1789702773711; Thu, 17 Sep 2026 20:39:33 -0700 (PDT) Received: from localhost.localdomain ([2409:8a1e:2e81:7320:79da:8b9b:16b2:8431]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-144cdfe957asm1039280c88.7.2026.09.17.20.39.28 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 17 Sep 2026 20:39:33 -0700 (PDT) From: Yuchao Zhang To: David Heidelberg Cc: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , oe-linux-nfc@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Yuchao Zhang Subject: [PATCH 1/1] nfc: llcp: reject connect() on sockets not in LLCP_CLOSED state Date: Fri, 18 Sep 2026 11:39:20 +0800 Message-ID: <20260918033920.85025-2-ndaugoing@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260918033920.85025-1-ndaugoing@gmail.com> References: <20260918033920.85025-1-ndaugoing@gmail.com> Precedence: bulk X-Mailing-List: oe-linux-nfc@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When a socket is bound via llcp_sock_bind(), its state transitions to LLCP_BOUND and it is linked into the local->sockets hlist via nfc_llcp_sock_link(). Currently, llcp_sock_connect() only checks if the socket is already connected (LLCP_CONNECTED) or in progress (LLCP_CONNECTING): if (sk->sk_state == LLCP_CONNECTED) { ret = -EISCONN; goto error; } if (sk->sk_state == LLCP_CONNECTING) { ret = -EINPROGRESS; goto error; } Crucially, it does not check for the LLCP_BOUND (or LLCP_LISTEN) state. Previous fixes addressing CVE-2020-25670 / CVE-2020-25673 added the check for LLCP_CONNECTING to prevent duplicate in-flight connection attempts from corrupting the connecting_sockets list. However, they assumed any other non-connected socket was in LLCP_CLOSED, leaving the LLCP_BOUND state window unhandled. If connect() is invoked on a socket that has already been bound: 1. llcp_sock_connect() silently overwrites llcp_sock->dev and llcp_sock->local without releasing previous references or freeing the bound service_name, leading to refcount and memory leaks. 2. The socket remains linked in local->sockets, while llcp_sock_connect() links it again into local->connecting_sockets via nfc_llcp_sock_link(). 3. When connection confirmation (CC) arrives, nfc_llcp_recv_cc() executes: nfc_llcp_sock_unlink(&local->connecting_sockets, sk); nfc_llcp_sock_link(&local->sockets, sk); Because sk was never unlinked from local->sockets, the head.first of local->sockets still points to &sk->sk_node. The second hlist_add_head() sets sk->sk_node.next = sk->sk_node, producing a self-referential loop. Subsequent traversals of local->sockets (e.g. nfc_llcp_sock_get(), nfc_llcp_socket_release()) enter an infinite loop with spinlocks held, resulting in kernel soft-lockups. 4. Furthermore, if connect() specifies a different NFC device index than bind(), the socket remains linked on device A's socket list while being assigned to device B, causing cross-device socket confusion. Fix this by ensuring that llcp_sock_connect() only accepts sockets in the LLCP_CLOSED state, returning -EBADFD otherwise, matching the state check behavior in llcp_sock_bind(). Fixes: d646960f7986 ("NFC: Initial LLCP support") Signed-off-by: Yuchao Zhang --- net/nfc/llcp_sock.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c index 5558d8a4d48b..66f12e9af2fd 100644 --- a/net/nfc/llcp_sock.c +++ b/net/nfc/llcp_sock.c @@ -689,6 +689,10 @@ static int llcp_sock_connect(struct socket *sock, struct sockaddr_unsized *_addr ret = -EINPROGRESS; goto error; } + if (sk->sk_state != LLCP_CLOSED) { + ret = -EBADFD; + goto error; + } dev = nfc_get_device(addr->dev_idx); if (dev == NULL) { -- 2.53.0