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Commit 300acfde authored by Marcel Holtmann's avatar Marcel Holtmann
Browse files

Bluetooth: Introduce force_bredr_smp debugfs option for testing 



Testing cross-transport pairing that starts on BR/EDR is only valid when
using a controller with BR/EDR Secure Connections. Devices will indicate
this by providing BR/EDR SMP fixed channel over L2CAP. To allow testing
of this feature on Bluetooth 4.0 controller or controllers without the
BR/EDR Secure Connections features, introduce a force_bredr_smp debugfs
option that allows faking the required AES connection.

Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: default avatarJohan Hedberg <johan.hedberg@intel.com>
parent e8768f97

include/net/bluetooth/hci.h

+1 −0
Original line number Diff line number Diff line
@@ -174,6 +174,7 @@ enum { 
	HCI_DUT_MODE,

	HCI_FORCE_SC,

	HCI_FORCE_LESC,

	HCI_FORCE_BREDR_SMP,

	HCI_FORCE_STATIC_ADDR,

};

net/bluetooth/l2cap_core.c

+1 −1
Original line number Diff line number Diff line
@@ -6968,7 +6968,7 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon) 


	if (test_bit(HCI_LE_ENABLED, &hcon->hdev->dev_flags) &&

	    (bredr_sc_enabled(hcon->hdev) ||

	     test_bit(HCI_FORCE_LESC, &hcon->hdev->dbg_flags)))

	     test_bit(HCI_FORCE_BREDR_SMP, &hcon->hdev->dbg_flags)))

		conn->local_fixed_chan |= L2CAP_FC_SMP_BREDR;



	mutex_init(&conn->ident_lock);

net/bluetooth/smp.c

+74 −4
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
   SOFTWARE IS DISCLAIMED.

*/



#include <linux/debugfs.h>

#include <linux/crypto.h>

#include <linux/scatterlist.h>

#include <crypto/b128ops.h>
@@ -1675,7 +1676,7 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb) 
	if (conn->hcon->type == ACL_LINK) {

		/* We must have a BR/EDR SC link */

		if (!test_bit(HCI_CONN_AES_CCM, &conn->hcon->flags) &&

		    !test_bit(HCI_FORCE_LESC, &hdev->dbg_flags))

		    !test_bit(HCI_FORCE_BREDR_SMP, &hdev->dbg_flags))

			return SMP_CROSS_TRANSP_NOT_ALLOWED;



		set_bit(SMP_FLAG_SC, &smp->flags);
@@ -2738,7 +2739,7 @@ static void bredr_pairing(struct l2cap_chan *chan) 


	/* BR/EDR must use Secure Connections for SMP */

	if (!test_bit(HCI_CONN_AES_CCM, &hcon->flags) &&

	    !test_bit(HCI_FORCE_LESC, &hdev->dbg_flags))

	    !test_bit(HCI_FORCE_BREDR_SMP, &hdev->dbg_flags))

		return;



	/* If our LE support is not enabled don't do anything */
@@ -2976,6 +2977,66 @@ static void smp_del_chan(struct l2cap_chan *chan) 
	l2cap_chan_put(chan);

}



static ssize_t force_bredr_smp_read(struct file *file,

				    char __user *user_buf,

				    size_t count, loff_t *ppos)

{

	struct hci_dev *hdev = file->private_data;

	char buf[3];



	buf[0] = test_bit(HCI_FORCE_BREDR_SMP, &hdev->dbg_flags) ? 'Y': 'N';

	buf[1] = '\n';

	buf[2] = '\0';

	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);

}



static ssize_t force_bredr_smp_write(struct file *file,

				     const char __user *user_buf,

				     size_t count, loff_t *ppos)

{

	struct hci_dev *hdev = file->private_data;

	char buf[32];

	size_t buf_size = min(count, (sizeof(buf)-1));

	bool enable;



	if (copy_from_user(buf, user_buf, buf_size))

		return -EFAULT;



	buf[buf_size] = '\0';

	if (strtobool(buf, &enable))

		return -EINVAL;



	if (enable == test_bit(HCI_FORCE_BREDR_SMP, &hdev->dbg_flags))

		return -EALREADY;



	if (enable) {

		struct l2cap_chan *chan;



		chan = smp_add_cid(hdev, L2CAP_CID_SMP_BREDR);

		if (IS_ERR(chan))

			return PTR_ERR(chan);



		hdev->smp_bredr_data = chan;

	} else {

		struct l2cap_chan *chan;



		chan = hdev->smp_bredr_data;

		hdev->smp_bredr_data = NULL;

		smp_del_chan(chan);

	}



	change_bit(HCI_FORCE_BREDR_SMP, &hdev->dbg_flags);



	return count;

}



static const struct file_operations force_bredr_smp_fops = {

	.open		= simple_open,

	.read		= force_bredr_smp_read,

	.write		= force_bredr_smp_write,

	.llseek		= default_llseek,

};



int smp_register(struct hci_dev *hdev)

{

	struct l2cap_chan *chan;
@@ -2988,9 +3049,18 @@ int smp_register(struct hci_dev *hdev) 


	hdev->smp_data = chan;



	if (!lmp_sc_capable(hdev) &&

	    !test_bit(HCI_FORCE_LESC, &hdev->dbg_flags))

	/* If the controller does not support BR/EDR Secure Connections

	 * feature, then the BR/EDR SMP channel shall not be present.

	 *

	 * To test this with Bluetooth 4.0 controllers, create a debugfs

	 * switch that allows forcing BR/EDR SMP support and accepting

	 * cross-transport pairing on non-AES encrypted connections.

	 */

	if (!lmp_sc_capable(hdev)) {

		debugfs_create_file("force_bredr_smp", 0644, hdev->debugfs,

				    hdev, &force_bredr_smp_fops);

		return 0;

	}



	chan = smp_add_cid(hdev, L2CAP_CID_SMP_BREDR);

	if (IS_ERR(chan)) {