From 5981a8821b774ada0be512fd9bad7c241e17657e Mon Sep 17 00:00:00 2001 From: Claudio Takahasi Date: Thu, 25 Jul 2013 16:34:24 -0300 Subject: Bluetooth: Fix removing Long Term Key This patch fixes authentication failure on LE link re-connection when BlueZ acts as slave (peripheral). LTK is removed from the internal list after its first use causing PIN or Key missing reply when re-connecting the link. The LE Long Term Key Request event indicates that the master is attempting to encrypt or re-encrypt the link. Pre-condition: BlueZ host paired and running as slave. How to reproduce(master): 1) Establish an ACL LE encrypted link 2) Disconnect the link 3) Try to re-establish the ACL LE encrypted link (fails) > HCI Event: LE Meta Event (0x3e) plen 19 LE Connection Complete (0x01) Status: Success (0x00) Handle: 64 Role: Slave (0x01) ... @ Device Connected: 00:02:72:DC:29:C9 (1) flags 0x0000 > HCI Event: LE Meta Event (0x3e) plen 13 LE Long Term Key Request (0x05) Handle: 64 Random number: 875be18439d9aa37 Encryption diversifier: 0x76ed < HCI Command: LE Long Term Key Request Reply (0x08|0x001a) plen 18 Handle: 64 Long term key: 2aa531db2fce9f00a0569c7d23d17409 > HCI Event: Command Complete (0x0e) plen 6 LE Long Term Key Request Reply (0x08|0x001a) ncmd 1 Status: Success (0x00) Handle: 64 > HCI Event: Encryption Change (0x08) plen 4 Status: Success (0x00) Handle: 64 Encryption: Enabled with AES-CCM (0x01) ... @ Device Disconnected: 00:02:72:DC:29:C9 (1) reason 3 < HCI Command: LE Set Advertise Enable (0x08|0x000a) plen 1 Advertising: Enabled (0x01) > HCI Event: Command Complete (0x0e) plen 4 LE Set Advertise Enable (0x08|0x000a) ncmd 1 Status: Success (0x00) > HCI Event: LE Meta Event (0x3e) plen 19 LE Connection Complete (0x01) Status: Success (0x00) Handle: 64 Role: Slave (0x01) ... @ Device Connected: 00:02:72:DC:29:C9 (1) flags 0x0000 > HCI Event: LE Meta Event (0x3e) plen 13 LE Long Term Key Request (0x05) Handle: 64 Random number: 875be18439d9aa37 Encryption diversifier: 0x76ed < HCI Command: LE Long Term Key Request Neg Reply (0x08|0x001b) plen 2 Handle: 64 > HCI Event: Command Complete (0x0e) plen 6 LE Long Term Key Request Neg Reply (0x08|0x001b) ncmd 1 Status: Success (0x00) Handle: 64 > HCI Event: Disconnect Complete (0x05) plen 4 Status: Success (0x00) Handle: 64 Reason: Authentication Failure (0x05) @ Device Disconnected: 00:02:72:DC:29:C9 (1) reason 0 Signed-off-by: Claudio Takahasi Cc: stable@vger.kernel.org Signed-off-by: Johan Hedberg --- net/bluetooth/hci_event.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index c3b0a08f5ab4..128e65ac60ae 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -3961,7 +3961,13 @@ static void hci_le_ltk_request_evt(struct hci_dev *hdev, struct sk_buff *skb) hci_send_cmd(hdev, HCI_OP_LE_LTK_REPLY, sizeof(cp), &cp); - if (ltk->type & HCI_SMP_STK) { + /* Ref. Bluetooth Core SPEC pages 1975 and 2004. STK is a + * temporary key used to encrypt a connection following + * pairing. It is used during the Encrypted Session Setup to + * distribute the keys. Later, security can be re-established + * using a distributed LTK. + */ + if (ltk->type == HCI_SMP_STK_SLAVE) { list_del(<k->list); kfree(ltk); } -- cgit v1.2.3