From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6A92C43E07B; Tue, 21 Jul 2026 22:19:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784672371; cv=none; b=YtMdqtC89K99Pi+UMllY+dRmeE2eRjEU7tOV3lnX/n+s3EgcxZpIKN3Mv71bBRyYbPSw4H0pVrEDZs3waUCnWvGZ0GWsRXAQVUriTGzAA0GLYmX1nqFk+LZettduZVInSOD1YAOZoVYYq5Y4k5W6cf56LzZCVBnpaHaKBYDFqU0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784672371; c=relaxed/simple; bh=PNKo230yCdufEAwiWhkWVaGkMRq3/xsvbnNZFFvcEss=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NrvydgTuKHgy2XjOGinIfDYLpmFB/LaLN0ZlcHwUCG26aFmLU3p0vBgf3UCLdDGjTji11LoNX0WvZc2g8h4BNsUXldMuqPhkO+mBmdYC0AY190iAL14Jw9zf65JiW//xb7jcQxZ2jZiewG0rewvqIq+Wfw3jy3zozJkRdM3XKPQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Z6Ec2OA4; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Z6Ec2OA4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFCD31F00A3E; Tue, 21 Jul 2026 22:19:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784672370; bh=3GxcJQDBUKoDF8Rc3C54sMZJVCRtHG2rcPUmh9HLYD0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Z6Ec2OA4w2F6ZjqcSrrSXseKY7wlSoWgMCysWG5UoFwuRxpP9wgS5wMU22UyCO/TJ 8a5JonyBSZOOalAlYtJFuhYXH+E7WYag3BY5wzu+oL+RMHdf2YcHXZB7uouEEi1KV1 mdc2YquPDxaLcSEaWD2sguQnaPI3h3253uYKljFk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pauli Virtanen , Luiz Augusto von Dentz Subject: [PATCH 5.15 600/843] Bluetooth: SCO: hold sk properly in sco_conn_ready Date: Tue, 21 Jul 2026 17:23:55 +0200 Message-ID: <20260721152419.545576607@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pauli Virtanen commit 4e37f6452d586b95c346a9abdd2fb80b67794f39 upstream. sk deref in sco_conn_ready must be done either under conn->lock, or holding a refcount, to avoid concurrent close. conn->sk and parent sk is currently accessed without either, and without checking parent->sk_state: [Task 1] [Task 2] sco_sock_release sco_conn_ready sk = conn->sk lock_sock(sk) conn->sk = NULL lock_sock(sk) release_sock(sk) sco_sock_kill(sk) UAF on sk deref and similarly for access to sco_get_sock_listen() return value. Fix possible UAF by holding sk refcount in sco_conn_ready() and making sco_get_sock_listen() increase refcount. Also recheck after lock_sock that the socket is still valid. Adjust conn->sk locking so it's protected also by lock_sock() of the associated socket if any. Fixes: 27c24fda62b60 ("Bluetooth: switch to lock_sock in SCO") Signed-off-by: Pauli Virtanen Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/sco.c | 44 ++++++++++++++++++++++++++++++++------------ 1 file changed, 32 insertions(+), 12 deletions(-) --- a/net/bluetooth/sco.c +++ b/net/bluetooth/sco.c @@ -371,9 +371,13 @@ static struct sock *sco_get_sock_listen( sk1 = sk; } + sk = sk ? sk : sk1; + if (sk) + sock_hold(sk); + read_unlock(&sco_sk_list.lock); - return sk ? sk : sk1; + return sk; } static void sco_sock_destruct(struct sock *sk) @@ -413,11 +417,13 @@ static void sco_sock_kill(struct sock *s BT_DBG("sk %p state %d", sk, sk->sk_state); /* Sock is dead, so set conn->sk to NULL to avoid possible UAF */ + lock_sock(sk); if (sco_pi(sk)->conn) { sco_conn_lock(sco_pi(sk)->conn); sco_pi(sk)->conn->sk = NULL; sco_conn_unlock(sco_pi(sk)->conn); } + release_sock(sk); /* Kill poor orphan */ bt_sock_unlink(&sco_sk_list, sk); @@ -1114,17 +1120,28 @@ static int sco_sock_release(struct socke static void sco_conn_ready(struct sco_conn *conn) { - struct sock *parent; - struct sock *sk = conn->sk; + struct sock *parent, *sk; + + sco_conn_lock(conn); + sk = sco_sock_hold(conn); + sco_conn_unlock(conn); BT_DBG("conn %p", conn); if (sk) { lock_sock(sk); - sco_sock_clear_timer(sk); - sk->sk_state = BT_CONNECTED; - sk->sk_state_change(sk); + + /* conn->sk may have become NULL if racing with sk close, but + * due to held hdev->lock, it can't become different sk. + */ + if (conn->sk) { + sco_sock_clear_timer(sk); + sk->sk_state = BT_CONNECTED; + sk->sk_state_change(sk); + } + release_sock(sk); + sock_put(sk); } else { if (!conn->hcon) return; @@ -1139,13 +1156,15 @@ static void sco_conn_ready(struct sco_co sco_conn_lock(conn); + /* hdev->lock guarantees conn->sk == NULL still here */ + + if (parent->sk_state != BT_LISTEN) + goto release; + sk = sco_sock_alloc(sock_net(parent), NULL, BTPROTO_SCO, GFP_ATOMIC, 0); - if (!sk) { - sco_conn_unlock(conn); - release_sock(parent); - return; - } + if (!sk) + goto release; sco_sock_init(sk, parent); @@ -1163,9 +1182,10 @@ static void sco_conn_ready(struct sco_co /* Wake up parent */ parent->sk_data_ready(parent); +release: sco_conn_unlock(conn); - release_sock(parent); + sock_put(parent); } }