From 54790f73a3ec87c181e4d6e5eb6963de3d50ebd7 Mon Sep 17 00:00:00 2001 From: Vinicius Costa Gomes Date: Thu, 7 Jul 2011 18:59:38 -0300 Subject: [PATCH] Bluetooth: Fix SM pairing parameters negotiation Before implementing SM key distribution, the pairing features exchange must be better negotiated, taking into account some features of the host and connection requirements. If we are in the "not pairable" state, it makes no sense to exchange any key. This allows for simplification of the key negociation method. Signed-off-by: Vinicius Costa Gomes Signed-off-by: Gustavo F. Padovan --- net/bluetooth/smp.c | 40 ++++++++++++++++++++++++++++++---------- 1 file changed, 30 insertions(+), 10 deletions(-) diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c index 82443b95f24e..ffbfdd9e5738 100644 --- a/net/bluetooth/smp.c +++ b/net/bluetooth/smp.c @@ -197,14 +197,34 @@ static __u8 seclevel_to_authreq(__u8 level) } static void build_pairing_cmd(struct l2cap_conn *conn, - struct smp_cmd_pairing *cmd, __u8 authreq) + struct smp_cmd_pairing *req, + struct smp_cmd_pairing *rsp, + __u8 authreq) { - cmd->io_capability = conn->hcon->io_capability; - cmd->oob_flag = SMP_OOB_NOT_PRESENT; - cmd->max_key_size = SMP_MAX_ENC_KEY_SIZE; - cmd->init_key_dist = SMP_DIST_ENC_KEY | SMP_DIST_ID_KEY | SMP_DIST_SIGN; - cmd->resp_key_dist = SMP_DIST_ENC_KEY | SMP_DIST_ID_KEY | SMP_DIST_SIGN; - cmd->auth_req = authreq; + u8 dist_keys; + + dist_keys = 0; + if (test_bit(HCI_PAIRABLE, &conn->hcon->hdev->flags)) { + dist_keys = SMP_DIST_ENC_KEY | SMP_DIST_ID_KEY | SMP_DIST_SIGN; + authreq |= SMP_AUTH_BONDING; + } + + if (rsp == NULL) { + req->io_capability = conn->hcon->io_capability; + req->oob_flag = SMP_OOB_NOT_PRESENT; + req->max_key_size = SMP_MAX_ENC_KEY_SIZE; + req->init_key_dist = dist_keys; + req->resp_key_dist = dist_keys; + req->auth_req = authreq; + return; + } + + rsp->io_capability = conn->hcon->io_capability; + rsp->oob_flag = SMP_OOB_NOT_PRESENT; + rsp->max_key_size = SMP_MAX_ENC_KEY_SIZE; + rsp->init_key_dist = req->init_key_dist & dist_keys; + rsp->resp_key_dist = req->resp_key_dist & dist_keys; + rsp->auth_req = authreq; } static u8 check_enc_key_size(struct l2cap_conn *conn, __u8 max_key_size) @@ -233,7 +253,7 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb) return SMP_OOB_NOT_AVAIL; /* We didn't start the pairing, so no requirements */ - build_pairing_cmd(conn, &rsp, SMP_AUTH_NONE); + build_pairing_cmd(conn, req, &rsp, SMP_AUTH_NONE); key_size = min(req->max_key_size, rsp.max_key_size); if (check_enc_key_size(conn, key_size)) @@ -412,7 +432,7 @@ static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb) skb_pull(skb, sizeof(*rp)); memset(&cp, 0, sizeof(cp)); - build_pairing_cmd(conn, &cp, rp->auth_req); + build_pairing_cmd(conn, &cp, NULL, rp->auth_req); conn->preq[0] = SMP_CMD_PAIRING_REQ; memcpy(&conn->preq[1], &cp, sizeof(cp)); @@ -454,7 +474,7 @@ int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level) if (hcon->link_mode & HCI_LM_MASTER) { struct smp_cmd_pairing cp; - build_pairing_cmd(conn, &cp, authreq); + build_pairing_cmd(conn, &cp, NULL, authreq); conn->preq[0] = SMP_CMD_PAIRING_REQ; memcpy(&conn->preq[1], &cp, sizeof(cp)); -- 2.20.1