Re: [bluetooth-next 04/15] Bluetooth: Add support for using the crypto subsystem

["Gustavo F. Padovan" <padovan@profusion.mobi>]

Hi Vinicius,

* Vinicius Costa Gomes <vinicius.gomes@openbossa.org> [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 <vinicius.gomes@openbossa.org>
> Signed-off-by: Anderson Briglia <anderson.briglia@openbossa.org>
> ---
>  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 <linux/notifier.h>
>  #include <linux/rfkill.h>
>  #include <linux/timer.h>
> +#include <linux/crypto.h>
>  #include <net/sock.h>
>  
>  #include <asm/system.h>
> @@ -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

Regards,

-- 
Gustavo F. Padovan
http://profusion.mobi