From patchwork Tue May 2 21:25:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luiz Augusto von Dentz X-Patchwork-Id: 678455 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 96686C7EE21 for ; Tue, 2 May 2023 21:25:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229883AbjEBVZh (ORCPT ); Tue, 2 May 2023 17:25:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33162 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229732AbjEBVZg (ORCPT ); Tue, 2 May 2023 17:25:36 -0400 Received: from mail-pf1-x434.google.com (mail-pf1-x434.google.com [IPv6:2607:f8b0:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 881DA1734 for ; Tue, 2 May 2023 14:25:34 -0700 (PDT) Received: by mail-pf1-x434.google.com with SMTP id d2e1a72fcca58-63b7096e2e4so3468016b3a.2 for ; Tue, 02 May 2023 14:25:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1683062733; x=1685654733; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:from:to:cc:subject:date:message-id :reply-to; bh=70Rh+2ZpfORm90qgVv/tSVn6I2FZ1MSGL8nzIsbeT5Y=; b=Z9+useJO9jwOsY01+7O0Irpjf0WH81hCihJL1b944/gFubDyorF5OFGCByb1WmRSG0 /cUWH+BzrOtpdmt0ijDwQ0l8iAE6svAoXit0DN84Sz31rb43pxIGyNM4fUnxcsJbYICG lc/h3nP5K0bp2AjL0VJt+rOFdoGPfO2AzC2+htkAEoqZJcVs6IbivJaXs4oKadrxH1M3 bmp00SJWNTSbtd5CE4ztBaBNE17ooIh0unUyACOjB8YyvAhsjQtOjreCw0DVZDBH9dW2 gcfinAK1ji6qDwOYrLJaXshMABw0jokWpaLf0NOsH64/GrQlSldFQTec15ltbTK2yKz5 MVxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683062733; x=1685654733; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=70Rh+2ZpfORm90qgVv/tSVn6I2FZ1MSGL8nzIsbeT5Y=; b=E94RBu4/GVG1RdSJxtsTgbu904tR032AzGtSiWWcG+13IkvFa0FRKA9kX1A7pdWF/j AQ8JxfQpyjx0Txs4cM283puGbJcJVKY6vltJ6sFriowlbUp95dxVh+lyHDLE17sK8Mjd NfXQgdxqUxQC7x37nHqpxg+MPbrcY00uARm7hsIeTp/KrJ7Scetz2u4p0WcIU+bA+NJI KqMDw+PvhnCAI7Srl7jjbU2ibqnuGQmF9dEf92Ob2aWHwN9xkQ+NfF0G7vWFDLIwa0vg Ul6oAZSmOy462NbRCssaW2xcvkJhtBCMMjogSFKiwQ9USL5YAb1yo5cePl1o/lEZjmLH VdDw== X-Gm-Message-State: AC+VfDyVlUi9jU6KjXRVcSvnWxPFXhMjs2rPs5d5zhljH7FXuSHYCJkx +J40YGHhff0irl/bOTFPb3y28tXMBHg= X-Google-Smtp-Source: ACHHUZ7rlKYxiXD44KxoPTKjJesUoZWP0R7nxPTnp29DwJ/VeIjKHGgoCnD1tn07lyjQRCk5lwArVw== X-Received: by 2002:aa7:8890:0:b0:63b:85a0:142a with SMTP id z16-20020aa78890000000b0063b85a0142amr28384407pfe.3.1683062733086; Tue, 02 May 2023 14:25:33 -0700 (PDT) Received: from lvondent-mobl4.. (c-71-59-129-171.hsd1.or.comcast.net. [71.59.129.171]) by smtp.gmail.com with ESMTPSA id j9-20020a056a00234900b0063d3d776910sm22232459pfj.138.2023.05.02.14.25.31 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 May 2023 14:25:31 -0700 (PDT) From: Luiz Augusto von Dentz To: linux-bluetooth@vger.kernel.org Subject: [PATCH v3 3/4] Bluetooth: Fix UAF in hci_conn_hash_flush again Date: Tue, 2 May 2023 14:25:26 -0700 Message-Id: <20230502212527.1662896-3-luiz.dentz@gmail.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230502212527.1662896-1-luiz.dentz@gmail.com> References: <20230502212527.1662896-1-luiz.dentz@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org From: Ruihan Li Commit 06149746e720 ("Bluetooth: hci_conn: Add support for linking multiple hcon") reintroduced a previously fixed bug [1] ("KASAN: slab-use-after-free Read in hci_conn_hash_flush"). This bug was originally fixed by commit 5dc7d23e167e ("Bluetooth: hci_conn: Fix possible UAF"). The hci_conn_unlink function was added to avoid invalidating the link traversal caused by successive hci_conn_del operations releasing extra connections. However, currently hci_conn_unlink itself also releases extra connections, resulted in the reintroduced bug. This patch follows a more robust solution for cleaning up all connections, by repeatedly removing the first connection until there are none left. This approach does not rely on the inner workings of hci_conn_del and ensures proper cleanup of all connections. Meanwhile, we need to make sure that hci_conn_del never fails. Indeed it doesn't, as it now always returns zero. To make this a bit clearer, this patch also changes its return type to void. Reported-by: syzbot+8bb72f86fc823817bc5d@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-bluetooth/000000000000aa920505f60d25ad@google.com/ Fixes: 06149746e720 ("Bluetooth: hci_conn: Add support for linking multiple hcon") Signed-off-by: Ruihan Li Signed-off-by: Luiz Augusto von Dentz --- include/net/bluetooth/hci_core.h | 2 +- net/bluetooth/hci_conn.c | 33 +++++++++++++++++++++----------- 2 files changed, 23 insertions(+), 12 deletions(-) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index a6c8aee2f256..8baf34639939 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -1327,7 +1327,7 @@ int hci_le_create_cis(struct hci_conn *conn); struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst, u8 role); -int hci_conn_del(struct hci_conn *conn); +void hci_conn_del(struct hci_conn *conn); void hci_conn_hash_flush(struct hci_dev *hdev); void hci_conn_check_pending(struct hci_dev *hdev); diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 44d0643fc681..ce588359b290 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -1088,6 +1088,14 @@ static void hci_conn_unlink(struct hci_conn *conn) hci_conn_unlink(child); + /* If hdev is down it means + * hci_dev_close_sync/hci_conn_hash_flush is in progress + * and links don't need to be cleanup as all connections + * would be cleanup. + */ + if (!test_bit(HCI_UP, &hdev->flags)) + continue; + /* Due to race, SCO connection might be not established * yet at this point. Delete it now, otherwise it is * possible for it to be stuck and can't be deleted. @@ -1112,7 +1120,7 @@ static void hci_conn_unlink(struct hci_conn *conn) conn->link = NULL; } -int hci_conn_del(struct hci_conn *conn) +void hci_conn_del(struct hci_conn *conn) { struct hci_dev *hdev = conn->hdev; @@ -1163,8 +1171,6 @@ int hci_conn_del(struct hci_conn *conn) * rest of hci_conn_del. */ hci_conn_cleanup(conn); - - return 0; } struct hci_dev *hci_get_route(bdaddr_t *dst, bdaddr_t *src, uint8_t src_type) @@ -2465,22 +2471,27 @@ void hci_conn_enter_active_mode(struct hci_conn *conn, __u8 force_active) /* Drop all connection on the device */ void hci_conn_hash_flush(struct hci_dev *hdev) { - struct hci_conn_hash *h = &hdev->conn_hash; - struct hci_conn *c, *n; + struct list_head *head = &hdev->conn_hash.list; + struct hci_conn *conn; BT_DBG("hdev %s", hdev->name); - list_for_each_entry_safe(c, n, &h->list, list) { - c->state = BT_CLOSED; - - hci_disconn_cfm(c, HCI_ERROR_LOCAL_HOST_TERM); + /* We should not traverse the list here, because hci_conn_del + * can remove extra links, which may cause the list traversal + * to hit items that have already been released. + */ + while ((conn = list_first_entry_or_null(head, + struct hci_conn, + list)) != NULL) { + conn->state = BT_CLOSED; + hci_disconn_cfm(conn, HCI_ERROR_LOCAL_HOST_TERM); /* Unlink before deleting otherwise it is possible that * hci_conn_del removes the link which may cause the list to * contain items already freed. */ - hci_conn_unlink(c); - hci_conn_del(c); + hci_conn_unlink(conn); + hci_conn_del(conn); } }