From patchwork Wed May 3 13:39:36 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ruihan Li X-Patchwork-Id: 13230191 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 9D31EC77B78 for ; Wed, 3 May 2023 13:40:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230208AbjECNkQ (ORCPT ); Wed, 3 May 2023 09:40:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230197AbjECNkP (ORCPT ); Wed, 3 May 2023 09:40:15 -0400 Received: from pku.edu.cn (mx18.pku.edu.cn [162.105.129.181]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 5AB4A5272 for ; Wed, 3 May 2023 06:40:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pku.edu.cn; s=dkim; h=Received:From:To:Cc:Subject:Date: Message-Id:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=1Cvfce/pAbE/ytwHNkPKg1BpVNhU/77VV8 IYSuC/d+8=; b=MlcHB396PxMOm1swVGwF8y5KasBrCkJwKC9T7SfSb68K5wFCbl ticdz6QO0oBWKywP9Cza8UwfyzR8eYmpcD1rDHx2LrvrIR9qZOFy7cKxsXrdSW4q ru0B3eqCiUDoejA/i7ak68W9oLM07CY8XUVe26TcqZmkhegkc4Jmh3e4E= Received: from localhost.localdomain (unknown [10.7.101.92]) by front02 (Coremail) with SMTP id 54FpogDn7k4iZFJkTkloEg--.11342S4; Wed, 03 May 2023 21:40:05 +0800 (CST) From: Ruihan Li To: linux-bluetooth@vger.kernel.org Cc: Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , Ruihan Li , syzbot+8bb72f86fc823817bc5d@syzkaller.appspotmail.com, Luiz Augusto von Dentz Subject: [PATCH v4 3/4] Bluetooth: Fix UAF in hci_conn_hash_flush again Date: Wed, 3 May 2023 21:39:36 +0800 Message-Id: <20230503133937.169647-3-lrh2000@pku.edu.cn> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230503133937.169647-1-lrh2000@pku.edu.cn> References: <20230503133937.169647-1-lrh2000@pku.edu.cn> MIME-Version: 1.0 X-CM-TRANSID: 54FpogDn7k4iZFJkTkloEg--.11342S4 X-Coremail-Antispam: 1UD129KBjvJXoWxXFyDWFW3Cry5Gr15Cr45ZFb_yoWrury8pa y5Wa45ur4kJrn3ZF1jyw4kAFn0qr1kZFy3KrW8J345J3yYyr4kArs0yryUtw45ArWkJF4U ZF4jqryxKFyUJ37anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9j1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AE w4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2 IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2 z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2vYz4IE04k24V AvwVAKI4IrM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xf McIj6xIIjxv20xvE14v26r126r1DMcIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7 v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxkIecxEwVCm -wCF04k20xvY0x0EwIxGrwCF04k20xvE74AGY7Cv6cx26w4UJr1UMxC20s026xCaFVCjc4 AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE 17CEb7AF67AKxVWUAVWUtwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMI IF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4l IxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvf C2KfnxnUUI43ZEXa7VUbX18DUUUUU== X-CM-SenderInfo: yssqiiarrvmko6sn3hxhgxhubq/1tbiAgEABVPy77yBwwAAs2 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org 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 Co-developed-by: Luiz Augusto von Dentz 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 a6c8aee2f..8baf34639 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 44d0643fc..ce588359b 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); } }