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 <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 82443b9..ffbfdd9 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -197,14 +197,34 @@
}
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 @@
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 @@
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 @@
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));