From patchwork Sat Aug 28 16:18:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takashi Iwai X-Patchwork-Id: 503812 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B254BC432BE for ; Sat, 28 Aug 2021 16:18:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7BD6D600D1 for ; Sat, 28 Aug 2021 16:18:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234449AbhH1QTQ (ORCPT ); Sat, 28 Aug 2021 12:19:16 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:47556 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229465AbhH1QTN (ORCPT ); Sat, 28 Aug 2021 12:19:13 -0400 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 48C142216D; Sat, 28 Aug 2021 16:18:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1630167502; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=7NrJ+Jhr63Y03bd2F44uKUO8GeWKhPO5AxFymYb2r/Y=; b=QFGFJAzTU9QMlsLhfBkgnewcQrt7Y5lLid8CoeSLHXRfYp4HnsTWL5Uwe2oArxxlXXU1Tf 0Qu1iNS1M+fufqLQ4cwZ6lX59eekJkwo0Q9i2ZgjACNqXaTPJOlAFEOSQ8TUh+XbtYE8YW YNPUlxCHqadOg3emwWoEILOEKbIrBno= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1630167502; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=7NrJ+Jhr63Y03bd2F44uKUO8GeWKhPO5AxFymYb2r/Y=; b=0pA5JPxTwbSi82qoLUOigRp7QS6I6qVGlSgTHqE+7BYixdOJSzpaO4jxHY2gfJItV+iyfL GCuk5aL/ACqHlpDA== Received: from alsa1.nue.suse.com (alsa1.suse.de [10.160.4.42]) by relay2.suse.de (Postfix) with ESMTP id 30AF0A3B9D; Sat, 28 Aug 2021 16:18:22 +0000 (UTC) From: Takashi Iwai To: Luiz Augusto von Dentz Cc: Marcel Holtmann , Johan Hedberg , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] Bluetooth: sco: Fix lock_sock() blockage by memcpy_from_msg() Date: Sat, 28 Aug 2021 18:18:18 +0200 Message-Id: <20210828161818.31141-1-tiwai@suse.de> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org The sco_send_frame() also takes lock_sock() during memcpy_from_msg() call that may be endlessly blocked by a task with userfaultd technique, and this will result in a hung task watchdog trigger. Just like the similar fix for hci_sock_sendmsg() in commit 92c685dc5de0 ("Bluetooth: reorganize functions..."), this patch moves the memcpy_from_msg() out of lock_sock() for addressing the hang. This should be the last piece for fixing CVE-2021-3640 after a few already queued fixes. Signed-off-by: Takashi Iwai --- net/bluetooth/sco.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c index 98a881586512..687e05718aad 100644 --- a/net/bluetooth/sco.c +++ b/net/bluetooth/sco.c @@ -280,7 +280,8 @@ static int sco_connect(struct hci_dev *hdev, struct sock *sk) return err; } -static int sco_send_frame(struct sock *sk, struct msghdr *msg, int len) +static int sco_send_frame(struct sock *sk, void *buf, int len, + unsigned int msg_flags) { struct sco_conn *conn = sco_pi(sk)->conn; struct sk_buff *skb; @@ -292,15 +293,11 @@ static int sco_send_frame(struct sock *sk, struct msghdr *msg, int len) BT_DBG("sk %p len %d", sk, len); - skb = bt_skb_send_alloc(sk, len, msg->msg_flags & MSG_DONTWAIT, &err); + skb = bt_skb_send_alloc(sk, len, msg_flags & MSG_DONTWAIT, &err); if (!skb) return err; - if (memcpy_from_msg(skb_put(skb, len), msg, len)) { - kfree_skb(skb); - return -EFAULT; - } - + memcpy(skb_put(skb, len), buf, len); hci_send_sco(conn->hcon, skb); return len; @@ -725,6 +722,7 @@ static int sco_sock_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) { struct sock *sk = sock->sk; + void *buf; int err; BT_DBG("sock %p, sk %p", sock, sk); @@ -736,14 +734,23 @@ static int sco_sock_sendmsg(struct socket *sock, struct msghdr *msg, if (msg->msg_flags & MSG_OOB) return -EOPNOTSUPP; + buf = kmalloc(len, GFP_KERNEL); + if (!buf) + return -ENOMEM; + if (memcpy_from_msg(buf, msg, len)) { + kfree(buf); + return -EFAULT; + } + lock_sock(sk); if (sk->sk_state == BT_CONNECTED) - err = sco_send_frame(sk, msg, len); + err = sco_send_frame(sk, buf, len, msg->msg_flags); else err = -ENOTCONN; release_sock(sk); + kfree(buf); return err; }