From patchwork Tue Sep 22 07:56:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Archie Pusaka X-Patchwork-Id: 11791793 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 04B2F6CB for ; Tue, 22 Sep 2020 07:56:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D259E239A1 for ; Tue, 22 Sep 2020 07:56:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="AucI3MRG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726567AbgIVH4S (ORCPT ); Tue, 22 Sep 2020 03:56:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726424AbgIVH4S (ORCPT ); Tue, 22 Sep 2020 03:56:18 -0400 Received: from mail-qt1-x84a.google.com (mail-qt1-x84a.google.com [IPv6:2607:f8b0:4864:20::84a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 18BF4C0613D0 for ; Tue, 22 Sep 2020 00:56:18 -0700 (PDT) Received: by mail-qt1-x84a.google.com with SMTP id b18so15405723qto.4 for ; Tue, 22 Sep 2020 00:56:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=ClKheBsVPCjUi1w0lCfGtWlJh8qfJBEdB5PCy2ar4eQ=; b=AucI3MRGxCu1uQ3YwRyhbF9AV90VUSbzOq+E13sGK46lv3zhafkIXVxlaRdbZkMOFp uD+RQhz++rvrSt6zSCfX/jNrMzRJDUKglbhV+XnvrPhf8d5vfmHukiMUmnCgNCeVYv0d 13PDmn7qysJV03qMFOEe+mdUoYRLiowtLKjq44/u9/viZqJFz8tM9/zjxebu5IypWNw1 as2UZN+TQH0E3iuIDsafThBzdP7AFwsToQprz9uMK1YtM7n35824NKcJnf3OLaAQESqV IPhbZNrRqs/Tmj6NLv8mloisoRhBVAzbirZftx6ipmL+J3MELZiMjgu7h51BMWwg6aoq 8xFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=ClKheBsVPCjUi1w0lCfGtWlJh8qfJBEdB5PCy2ar4eQ=; b=ENkYAGAKLy62snvzdHDwjgZng8GmlD7g3QnIjSgs1qSQZRovPiyGAODCPGrKmDHO57 dTdt5UGp+2An9RHcJbjq4stEM0hG3tNL6DKHH/TXenzf5L4vbjuh1LZ39EED86iXeUvr RFSj0cnM5XvRdr7V6SB0NUcgrPUa2kvhooEGoZNsa99OuBkKjyfqe6VFaAL09aG8LZ7h n93MKiMdMPuYhYfpmqlYI3Y0IdDNksk6uQSQIbUP0je4WvlhOxUcrxboBxJWKATFrz/g ltgsWgP3YYrN5z/s1TTNYPV/lrkHGaAwsRMnufrMFZpLupMaD4wR7O++bwWEfTQwLCPb Re9Q== X-Gm-Message-State: AOAM533Ql5ap7sGIGUVzPpFJ7IQ3z2kt7EzyXWOQBrJ63NUeaeMfM9gH 3wXBfYoGxe73WQUIJf8mwrCjfS2dPOXJC4W6XIOJ3ELzckVP+SAVm3E0VUxCLTBAQ8XH2eM7zct +I+P5SiWbQzWVW2u4fKSPHsbk4N5OzQHOpMGyCZH+wWR7fyojgIZ6Nx3Qe7b3x3d3ink+TJvArH zs X-Google-Smtp-Source: ABdhPJyR9yLwG5vy6sWNnj6uUqoZ9+AuNeiZPDSyud1VBRfooMC47509/9C+6TBmwN4TjtWXTMXV0zSHSyMT Sender: "apusaka via sendgmr" X-Received: from apusaka-p920.tpe.corp.google.com ([2401:fa00:1:10:f693:9fff:fef4:2347]) (user=apusaka job=sendgmr) by 2002:ad4:57cc:: with SMTP id y12mr4563202qvx.48.1600761376969; Tue, 22 Sep 2020 00:56:16 -0700 (PDT) Date: Tue, 22 Sep 2020 15:56:11 +0800 Message-Id: <20200922155548.v3.1.I67a8b8cd4def8166970ca37109db46d731b62bb6@changeid> Mime-Version: 1.0 X-Mailer: git-send-email 2.28.0.681.g6f77f65b4e-goog Subject: [PATCH v3] Bluetooth: Check for encryption key size on connect From: Archie Pusaka To: linux-bluetooth , Marcel Holtmann Cc: CrosBT Upstreaming , Archie Pusaka , "David S. Miller" , Jakub Kicinski , Johan Hedberg , linux-kernel@vger.kernel.org, netdev@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org From: Archie Pusaka When receiving connection, we only check whether the link has been encrypted, but not the encryption key size of the link. This patch adds check for encryption key size, and reject L2CAP connection which size is below the specified threshold (default 7) with security block. Here is some btmon trace. @ MGMT Event: New Link Key (0x0009) plen 26 {0x0001} [hci0] 5.847722 Store hint: No (0x00) BR/EDR Address: 38:00:25:F7:F1:B0 (OUI 38-00-25) Key type: Unauthenticated Combination key from P-192 (0x04) Link key: 7bf2f68c81305d63a6b0ee2c5a7a34bc PIN length: 0 > HCI Event: Encryption Change (0x08) plen 4 #29 [hci0] 5.871537 Status: Success (0x00) Handle: 256 Encryption: Enabled with E0 (0x01) < HCI Command: Read Encryp... (0x05|0x0008) plen 2 #30 [hci0] 5.871609 Handle: 256 > HCI Event: Command Complete (0x0e) plen 7 #31 [hci0] 5.872524 Read Encryption Key Size (0x05|0x0008) ncmd 1 Status: Success (0x00) Handle: 256 Key size: 3 ////// WITHOUT PATCH ////// > ACL Data RX: Handle 256 flags 0x02 dlen 12 #42 [hci0] 5.895023 L2CAP: Connection Request (0x02) ident 3 len 4 PSM: 4097 (0x1001) Source CID: 64 < ACL Data TX: Handle 256 flags 0x00 dlen 16 #43 [hci0] 5.895213 L2CAP: Connection Response (0x03) ident 3 len 8 Destination CID: 64 Source CID: 64 Result: Connection successful (0x0000) Status: No further information available (0x0000) ////// WITH PATCH ////// > ACL Data RX: Handle 256 flags 0x02 dlen 12 #42 [hci0] 4.887024 L2CAP: Connection Request (0x02) ident 3 len 4 PSM: 4097 (0x1001) Source CID: 64 < ACL Data TX: Handle 256 flags 0x00 dlen 16 #43 [hci0] 4.887127 L2CAP: Connection Response (0x03) ident 3 len 8 Destination CID: 0 Source CID: 64 Result: Connection refused - security block (0x0003) Status: No further information available (0x0000) Signed-off-by: Archie Pusaka --- Changes in v3: * Move the check to hci_conn_check_link_mode() Changes in v2: * Add btmon trace to the commit message net/bluetooth/hci_conn.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 9832f8445d43..89085fac797c 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -1348,6 +1348,10 @@ int hci_conn_check_link_mode(struct hci_conn *conn) !test_bit(HCI_CONN_ENCRYPT, &conn->flags)) return 0; + if (test_bit(HCI_CONN_ENCRYPT, &conn->flags) && + conn->enc_key_size < conn->hdev->min_enc_key_size) + return 0; + return 1; }