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Commit e3098be4 authored by Johan Hedberg's avatar Johan Hedberg Committed by Marcel Holtmann
Browse files

Bluetooth: Delay LTK encryption to let remote receive all keys 



Some devices may refuse to re-encrypt with the LTK if they haven't
received all our keys yet. This patch adds a 250ms delay before
attempting re-encryption with the LTK.

Signed-off-by: default avatarJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 38ccdc93

net/bluetooth/smp.c

+19 −3
Original line number Diff line number Diff line
@@ -549,6 +549,20 @@ static void random_work(struct work_struct *work) 
	smp_failure(conn, reason);

}



static void smp_reencrypt(struct work_struct *work)

{

	struct smp_chan *smp = container_of(work, struct smp_chan,

					    reencrypt.work);

	struct l2cap_conn *conn = smp->conn;

	struct hci_conn *hcon = conn->hcon;

	struct smp_ltk *ltk = smp->ltk;



	BT_DBG("");



	hci_le_start_enc(hcon, ltk->ediv, ltk->rand, ltk->val);

	hcon->enc_key_size = ltk->enc_size;

}



static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)

{

	struct smp_chan *smp;
@@ -559,6 +573,7 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn) 


	INIT_WORK(&smp->confirm, confirm_work);

	INIT_WORK(&smp->random, random_work);

	INIT_DELAYED_WORK(&smp->reencrypt, smp_reencrypt);



	smp->conn = conn;

	conn->smp_chan = smp;
@@ -576,6 +591,8 @@ void smp_chan_destroy(struct l2cap_conn *conn) 


	BUG_ON(!smp);



	cancel_delayed_work_sync(&smp->reencrypt);



	complete = test_bit(SMP_FLAG_COMPLETE, &smp->smp_flags);

	mgmt_smp_complete(conn->hcon, complete);
@@ -1287,9 +1304,8 @@ int smp_distribute_keys(struct l2cap_conn *conn) 


	/* Re-encrypt the link with LTK if possible */

	if (ltk_encrypt && hcon->out) {

		struct smp_ltk *ltk = smp->ltk;

		hci_le_start_enc(hcon, ltk->ediv, ltk->rand, ltk->val);

		hcon->enc_key_size = ltk->enc_size;

		queue_delayed_work(hdev->req_workqueue, &smp->reencrypt,

				   SMP_REENCRYPT_TIMEOUT);

	} else {

		clear_bit(HCI_CONN_LE_SMP_PEND, &hcon->flags);

		cancel_delayed_work_sync(&conn->security_timer);

net/bluetooth/smp.h

+3 −0
Original line number Diff line number Diff line
@@ -121,6 +121,8 @@ struct smp_cmd_security_req { 
#define SMP_FLAG_LTK_ENCRYPT	4

#define SMP_FLAG_COMPLETE	5



#define SMP_REENCRYPT_TIMEOUT	msecs_to_jiffies(250)



struct smp_chan {

	struct l2cap_conn *conn;

	u8		preq[7]; /* SMP Pairing Request */
@@ -140,6 +142,7 @@ struct smp_chan { 
	unsigned long	smp_flags;

	struct work_struct confirm;

	struct work_struct random;

	struct delayed_work reencrypt;

};



/* SMP Commands */