From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 28 Feb 2011 14:28:01 -0300 From: "Gustavo F. Padovan" To: Vinicius Gomes Cc: linux-bluetooth@vger.kernel.org, Anderson Briglia Subject: Re: [bluetooth-next 04/15] Bluetooth: Add support for using the crypto subsystem Message-ID: <20110228172801.GB2165@joana> References: <02fa778ab4292dffba1330e829b0d4029517a21e.1298307667.git.vinicius.gomes@openbossa.org> <20110227202041.GG2166@joana> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Vinicius, * Vinicius Gomes [2011-02-27 21:49:39 -0300]: > Hi Gustavo, > > On Sun, Feb 27, 2011 at 5:20 PM, Gustavo F. Padovan > wrote: > > Hi Vinicius, > > > > * Vinicius Costa Gomes [2011-02-21 14:23:51 -0300]: > > > >> This will allow using the crypto subsystem for encrypting data. As SMP > >> (Security Manager Protocol) is implemented almost entirely on the host > >> side and the crypto module already implements the needed methods > >> (AES-128), it makes sense to use it. > >> > >> This patch also adds a new Kconfig option to toggle the SMP support. > >> > >> Signed-off-by: Vinicius Costa Gomes > >> Signed-off-by: Anderson Briglia > >> --- > >>  include/net/bluetooth/hci_core.h |    2 ++ > >>  net/bluetooth/Kconfig            |    6 ++++++ > >>  net/bluetooth/hci_core.c         |   22 ++++++++++++++++++++++ > >>  net/bluetooth/smp.c              |   17 +++++++++++++++-- > >>  4 files changed, 45 insertions(+), 2 deletions(-) > >> > >> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h > >> index d5d8454..e8dbde8 100644 > >> --- a/include/net/bluetooth/hci_core.h > >> +++ b/include/net/bluetooth/hci_core.h > >> @@ -161,6 +161,8 @@ struct hci_dev { > >> > >>       __u16                   init_last_cmd; > >> > >> +     struct crypto_blkcipher *tfm; > >> + > >>       struct inquiry_cache    inq_cache; > >>       struct hci_conn_hash    conn_hash; > >>       struct list_head        blacklist; > >> diff --git a/net/bluetooth/Kconfig b/net/bluetooth/Kconfig > >> index c6f9c2f..e9f40af 100644 > >> --- a/net/bluetooth/Kconfig > >> +++ b/net/bluetooth/Kconfig > >> @@ -22,6 +22,7 @@ menuconfig BT > >>            BNEP Module (Bluetooth Network Encapsulation Protocol) > >>            CMTP Module (CAPI Message Transport Protocol) > >>            HIDP Module (Human Interface Device Protocol) > >> +          SMP Module (Security Manager Protocol) > >> > >>         Say Y here to compile Bluetooth support into the kernel or say M to > >>         compile it as module (bluetooth). > >> @@ -35,11 +36,16 @@ config BT_L2CAP > >>       bool "L2CAP protocol support" > >>       depends on BT > >>       select CRC16 > >> +     select CRYPTO_BLKCIPHER > >> +     select CRYPTO_AES > >>       help > >>         L2CAP (Logical Link Control and Adaptation Protocol) provides > >>         connection oriented and connection-less data transport.  L2CAP > >>         support is required for most Bluetooth applications. > >> > >> +       Also included is support for SMP (Security Manager Protocol) which > >> +       is the security layer on top of LE (Low Energy) links. > >> + > >>  config BT_SCO > >>       bool "SCO links support" > >>       depends on BT > >> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c > >> index b372fb8..ff67843 100644 > >> --- a/net/bluetooth/hci_core.c > >> +++ b/net/bluetooth/hci_core.c > >> @@ -42,6 +42,7 @@ > >>  #include > >>  #include > >>  #include > >> +#include > >>  #include > >> > >>  #include > >> @@ -60,6 +61,8 @@ static void hci_notify(struct hci_dev *hdev, int event); > >> > >>  static DEFINE_RWLOCK(hci_task_lock); > >> > >> +static int enable_smp; > >> + > >>  /* HCI device list */ > >>  LIST_HEAD(hci_dev_list); > >>  DEFINE_RWLOCK(hci_dev_list_lock); > >> @@ -1077,6 +1080,14 @@ static void hci_cmd_timer(unsigned long arg) > >>       tasklet_schedule(&hdev->cmd_task); > >>  } > >> > >> +static struct crypto_blkcipher *alloc_cypher(void) > >> +{ > >> +     if (enable_smp) > >> +             return crypto_alloc_blkcipher("ecb(aes)", 0, CRYPTO_ALG_ASYNC); > >> + > >> +     return ERR_PTR(-ENOTSUPP); > >> +} > >> + > >>  /* Register HCI device */ > >>  int hci_register_dev(struct hci_dev *hdev) > >>  { > >> @@ -1155,6 +1166,11 @@ int hci_register_dev(struct hci_dev *hdev) > >>       if (!hdev->workqueue) > >>               goto nomem; > >> > >> +     hdev->tfm = alloc_cypher(); > >> +     if (IS_ERR(hdev->tfm)) > >> +             BT_INFO("Failed to load transform for ecb(aes): %ld", > >> +                                                     PTR_ERR(hdev->tfm)); > >> + > >>       hci_register_sysfs(hdev); > >> > >>       hdev->rfkill = rfkill_alloc(hdev->name, &hdev->dev, > >> @@ -1203,6 +1219,9 @@ int hci_unregister_dev(struct hci_dev *hdev) > >>                                       !test_bit(HCI_SETUP, &hdev->flags)) > >>               mgmt_index_removed(hdev->id); > >> > >> +     if (!IS_ERR(hdev->tfm)) > >> +             crypto_free_blkcipher(hdev->tfm); > >> + > >>       hci_notify(hdev, HCI_DEV_UNREG); > >> > >>       if (hdev->rfkill) { > >> @@ -2037,3 +2056,6 @@ static void hci_cmd_task(unsigned long arg) > >>               } > >>       } > >>  } > >> + > >> +module_param(enable_smp, bool, 0644); > >> +MODULE_PARM_DESC(enable_smp, "Enable SMP support (LE only)"); > > > > This all should be obviously inside smp.c > > I have a couple of points against it: > > 1. it's only used for one purpose, it says whether to try or not to > allocate the block cypher, which is done during the adapter > registration; > > 2. If the current way is ok, it would mean that I would need to export > another method from smp.c, that was something that I tried to > minimize; > > 3. and my weakest argument, seems that there are other similar uses, > for example enable_mgmt. A similar example here is enable_ertm inside l2cap_core.c. It's a L2CAP related option and should reside inside L2CAP code. > > But if you think the code will be clearer moving that to smp.c, will > be glad to change. I don't see the point on have it on hci code. SMP and Block cypher has not much to do with HCI. I prefer it on smp.c -- Gustavo F. Padovan http://profusion.mobi