From patchwork Wed Jul 28 07:51:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Desmond Cheong Zhi Xi X-Patchwork-Id: 488892 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 641B5C4338F for ; Wed, 28 Jul 2021 07:52:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3820C60F9C for ; Wed, 28 Jul 2021 07:52:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234238AbhG1HwH (ORCPT ); Wed, 28 Jul 2021 03:52:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233407AbhG1HwG (ORCPT ); Wed, 28 Jul 2021 03:52:06 -0400 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44289C061757; Wed, 28 Jul 2021 00:52:04 -0700 (PDT) Received: by mail-pj1-x1029.google.com with SMTP id k4-20020a17090a5144b02901731c776526so8697274pjm.4; Wed, 28 Jul 2021 00:52:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=BfFfoe2qcsk90EiXHqmqBH9bAIL6WXwzwjqk2LV2VVk=; b=ppIUqaLekxhrUOEuMFOP5KxK5q8q7129j/z6DU0EJzkYRxjo62gKXr2wJvu8QG/yMm xhMyy9Wx7VIEwZV1otUjTONOQ9rx8N2PpciwEVRTLyCCo9vewTvMRfII4Ufk+BgnW9Dx M4KuDZAEKxvlcuFcsrjfKxl6s32AgBgkzlE4VGK+VBiclbMB0alcxkmPEOJqyEKa5LNv EmqYuUIQ0otQ9M2qT58HsgUtU8gcpuD/5uXEjPTLUfrdUisqhL+A12xgykRAYUIELkkr K1tR8aRtt9u9GfzLnkL1beWCueQkDX0wdd+/HFdwXt+RHY1guUH/GCMaP6SKALwqoaWF gNCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=BfFfoe2qcsk90EiXHqmqBH9bAIL6WXwzwjqk2LV2VVk=; b=c+UtA7Q1l26LK1tHfnhzqqKVZx2dk+fvaELsNIsg2yHQvr54NkfGzt1BaOlRv9fGsb iLKdNsrVlvBDg7nzemc3e3LNq/yKe8Ko4i8uz3DY8MuBDVyMNrIFFVv0jB0k9klsAvTd dOycrGmvb6BDDwjsQhgWErVLdodZAQjJXlXUH/aY/82nWOinWZl1KBOaXgiURH5Ylr8P qNpYnBfl2Jqx3LsKPmj43Aq6hURKhbALitIPT5viRfxIjjubl8/Lcy3dRok0SlFHhKvt jYYibhRGcJme+PdhvHtwlGxV+Nt/x4OT7AsB8Jw+EKvAuOSviXrLDJP4XKJPctd1Q75N fl5w== X-Gm-Message-State: AOAM532pFHG06Vh4+zRavT9cRDgGaWtChUHjIWtgLc55T/Vgmqt6eoCG uLCbY7xkkfRyQvZyzVkr4dU= X-Google-Smtp-Source: ABdhPJw42zg0Y3dEy18wgMq779F5L2gS2hIZZYw/51Zmz+CQ+5PANyu0aE6Ap5rABGFjTLBKbdm28w== X-Received: by 2002:a65:6909:: with SMTP id s9mr16014599pgq.321.1627458723697; Wed, 28 Jul 2021 00:52:03 -0700 (PDT) Received: from localhost.localdomain ([118.200.190.93]) by smtp.gmail.com with ESMTPSA id oj4sm4903482pjb.56.2021.07.28.00.52.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Jul 2021 00:52:03 -0700 (PDT) From: Desmond Cheong Zhi Xi To: marcel@holtmann.org, johan.hedberg@gmail.com, luiz.dentz@gmail.com, davem@davemloft.net, kuba@kernel.org Cc: Desmond Cheong Zhi Xi , linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, gregkh@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org, syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com Subject: [PATCH v2] Bluetooth: skip invalid hci_sync_conn_complete_evt Date: Wed, 28 Jul 2021 15:51:04 +0800 Message-Id: <20210728075105.415214-1-desmondcheongzx@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Syzbot reported a corrupted list in kobject_add_internal [1]. This happens when multiple HCI_EV_SYNC_CONN_COMPLETE event packets with status 0 are sent for the same HCI connection. This causes us to register the device more than once which corrupts the kset list. As this is forbidden behavior, we add a check for whether we're trying to process the same HCI_EV_SYNC_CONN_COMPLETE event multiple times for one connection. If that's the case, the event is invalid, so we report an error that the device is misbehaving, and ignore the packet. Link: https://syzkaller.appspot.com/bug?extid=66264bf2fd0476be7e6c [1] Reported-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com Tested-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com Signed-off-by: Desmond Cheong Zhi Xi --- v1 -> v2: - Added more comments to explain the reasoning behind the new check, and a bt_dev_err message upon detecting the invalid event. As suggested by Marcel Holtmann. net/bluetooth/hci_event.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 016b2999f219..a6df4f9d2c23 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -4373,6 +4373,22 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev, switch (ev->status) { case 0x00: + /* The synchronous connection complete event should only be + * sent once per new connection. Receiving a successful + * complete event when the connection status is already + * BT_CONNECTED means that the device is misbehaving and sent + * multiple complete event packets for the same new connection. + * + * Registering the device more than once can corrupt kernel + * memory, hence upon detecting this invalid event, we report + * an error and ignore the packet. + */ + if (conn->state == BT_CONNECTED) { + bt_dev_err(hdev, + "received multiple HCI_EV_SYNC_CONN_COMPLETE events with status 0 for conn %p", + conn); + goto unlock; + } conn->handle = __le16_to_cpu(ev->handle); conn->state = BT_CONNECTED; conn->type = ev->link_type;