Bluetooth: Add support for Pairing features exchange

This patch implements a simple version of the SMP Pairing Features
exchange procedure (Vol. 3 Part H, Section 2.3.5.1).

For now, everything that would cause a Pairing Method different of
Just Works to be chosen is rejected.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 21d6055..ac2c5e8 100644 (file)
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -1622,6 +1622,7 @@ static inline void hci_encrypt_change_evt(struct hci_dev *hdev, struct sk_buff *
                                /* Encryption implies authentication */
                                conn->link_mode |= HCI_LM_AUTH;
                                conn->link_mode |= HCI_LM_ENCRYPT;
+                               conn->sec_level = conn->pending_sec_level;
                        } else
                                conn->link_mode &= ~HCI_LM_ENCRYPT;
                }

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index d29700d..dfd6891 100644 (file)
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -181,6 +181,18 @@ static void smp_send_cmd(struct l2cap_conn *conn, u8 code, u16 len, void *data)
        hci_send_acl(conn->hcon, skb, 0);
 }
 
+static __u8 seclevel_to_authreq(__u8 level)
+{
+       switch (level) {
+       case BT_SECURITY_HIGH:
+               /* Right now we don't support bonding */
+               return SMP_AUTH_MITM;
+
+       default:
+               return SMP_AUTH_NONE;
+       }
+}
+
 static void build_pairing_cmd(struct l2cap_conn *conn,
                                struct smp_cmd_pairing *cmd, __u8 authreq)
 {
@@ -192,7 +204,7 @@ static void build_pairing_cmd(struct l2cap_conn *conn,
        cmd->auth_req = authreq;
 }
 
-static void smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
+static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 {
        struct smp_cmd_pairing *rp = (void *) skb->data;
 
@@ -202,12 +214,11 @@ static void smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
        memcpy(&conn->preq[1], rp, sizeof(*rp));
        skb_pull(skb, sizeof(*rp));
 
-       rp->io_capability = 0x00;
-       rp->oob_flag = 0x00;
-       rp->max_key_size = 16;
-       rp->init_key_dist = 0x00;
-       rp->resp_key_dist = 0x00;
-       rp->auth_req &= (SMP_AUTH_BONDING | SMP_AUTH_MITM);
+       if (rp->oob_flag)
+               return SMP_OOB_NOT_AVAIL;
+
+       /* We didn't start the pairing, so no requirements */
+       build_pairing_cmd(conn, rp, SMP_AUTH_NONE);
 
        /* Just works */
        memset(conn->tk, 0, sizeof(conn->tk));
@@ -216,9 +227,11 @@ static void smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
        memcpy(&conn->prsp[1], rp, sizeof(*rp));
 
        smp_send_cmd(conn, SMP_CMD_PAIRING_RSP, sizeof(*rp), rp);
+
+       return 0;
 }
 
-static void smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
+static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
 {
        struct smp_cmd_pairing *rp = (void *) skb->data;
        struct smp_cmd_pairing_confirm cp;
@@ -228,29 +241,34 @@ static void smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
 
        BT_DBG("conn %p", conn);
 
+       skb_pull(skb, sizeof(*rp));
+
+       if (rp->oob_flag)
+               return SMP_OOB_NOT_AVAIL;
+
        /* Just works */
        memset(conn->tk, 0, sizeof(conn->tk));
 
        conn->prsp[0] = SMP_CMD_PAIRING_RSP;
        memcpy(&conn->prsp[1], rp, sizeof(*rp));
-       skb_pull(skb, sizeof(*rp));
 
        ret = smp_rand(conn->prnd);
        if (ret)
-               return;
+               return SMP_UNSPECIFIED;
 
        ret = smp_c1(tfm, conn->tk, conn->prnd, conn->preq, conn->prsp, 0,
                        conn->src, conn->hcon->dst_type, conn->dst, res);
        if (ret)
-               return;
+               return SMP_UNSPECIFIED;
 
        swap128(res, cp.confirm_val);
 
        smp_send_cmd(conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cp), &cp);
+
+       return 0;
 }
 
-static void smp_cmd_pairing_confirm(struct l2cap_conn *conn,
-                                                       struct sk_buff *skb)
+static u8 smp_cmd_pairing_confirm(struct l2cap_conn *conn, struct sk_buff *skb)
 {
        struct crypto_blkcipher *tfm = conn->hcon->hdev->tfm;
 
@@ -272,21 +290,23 @@ static void smp_cmd_pairing_confirm(struct l2cap_conn *conn,
 
                ret = smp_rand(conn->prnd);
                if (ret)
-                       return;
+                       return SMP_UNSPECIFIED;
 
                ret = smp_c1(tfm, conn->tk, conn->prnd, conn->preq, conn->prsp,
                                                conn->hcon->dst_type, conn->dst,
                                                0, conn->src, res);
                if (ret)
-                       return;
+                       return SMP_CONFIRM_FAILED;
 
                swap128(res, cp.confirm_val);
 
                smp_send_cmd(conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cp), &cp);
        }
+
+       return 0;
 }
 
-static void smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
+static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
 {
        struct hci_conn *hcon = conn->hcon;
        struct crypto_blkcipher *tfm = hcon->hdev->tfm;
@@ -307,19 +327,15 @@ static void smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
                                conn->hcon->dst_type, conn->dst, 0, conn->src,
                                res);
        if (ret)
-               return;
+               return SMP_UNSPECIFIED;
 
        BT_DBG("conn %p %s", conn, conn->hcon->out ? "master" : "slave");
 
        swap128(res, confirm);
 
        if (memcmp(conn->pcnf, confirm, sizeof(conn->pcnf)) != 0) {
-               struct smp_cmd_pairing_fail cp;
-
                BT_ERR("Pairing failed (confirmation values mismatch)");
-               cp.reason = SMP_CONFIRM_FAILED;
-               smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(cp), &cp);
-               return;
+               return SMP_CONFIRM_FAILED;
        }
 
        if (conn->hcon->out) {
@@ -341,9 +357,11 @@ static void smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
                smp_s1(tfm, conn->tk, conn->prnd, random, key);
                swap128(key, hcon->ltk);
        }
+
+       return 0;
 }
 
-static void smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
+static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
 {
        struct smp_cmd_security_req *rp = (void *) skb->data;
        struct smp_cmd_pairing cp;
@@ -352,17 +370,12 @@ static void smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
        BT_DBG("conn %p", conn);
 
        if (test_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend))
-               return;
+               return 0;
 
        skb_pull(skb, sizeof(*rp));
-       memset(&cp, 0, sizeof(cp));
 
-       cp.io_capability = 0x00;
-       cp.oob_flag = 0x00;
-       cp.max_key_size = 16;
-       cp.init_key_dist = 0x00;
-       cp.resp_key_dist = 0x00;
-       cp.auth_req = rp->auth_req & (SMP_AUTH_BONDING | SMP_AUTH_MITM);
+       memset(&cp, 0, sizeof(cp));
+       build_pairing_cmd(conn, &cp, rp->auth_req);
 
        conn->preq[0] = SMP_CMD_PAIRING_REQ;
        memcpy(&conn->preq[1], &cp, sizeof(cp));
@@ -370,18 +383,8 @@ static void smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
        smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp);
 
        set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend);
-}
 
-static __u8 seclevel_to_authreq(__u8 level)
-{
-       switch (level) {
-       case BT_SECURITY_HIGH:
-               /* For now we don't support bonding */
-               return SMP_AUTH_MITM;
-
-       default:
-               return SMP_AUTH_NONE;
-       }
+       return 0;
 }
 
 int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level)
@@ -407,13 +410,8 @@ int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level)
 
        if (hcon->link_mode & HCI_LM_MASTER) {
                struct smp_cmd_pairing cp;
-               cp.io_capability = 0x00;
-               cp.oob_flag = 0x00;
-               cp.max_key_size = 16;
-               cp.init_key_dist = 0x00;
-               cp.resp_key_dist = 0x00;
-               cp.auth_req = authreq;
 
+               build_pairing_cmd(conn, &cp, authreq);
                conn->preq[0] = SMP_CMD_PAIRING_REQ;
                memcpy(&conn->preq[1], &cp, sizeof(cp));
 
@@ -446,26 +444,28 @@ int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb)
 
        switch (code) {
        case SMP_CMD_PAIRING_REQ:
-               smp_cmd_pairing_req(conn, skb);
+               reason = smp_cmd_pairing_req(conn, skb);
                break;
 
        case SMP_CMD_PAIRING_FAIL:
+               reason = 0;
+               err = -EPERM;
                break;
 
        case SMP_CMD_PAIRING_RSP:
-               smp_cmd_pairing_rsp(conn, skb);
+               reason = smp_cmd_pairing_rsp(conn, skb);
                break;
 
        case SMP_CMD_SECURITY_REQ:
-               smp_cmd_security_req(conn, skb);
+               reason = smp_cmd_security_req(conn, skb);
                break;
 
        case SMP_CMD_PAIRING_CONFIRM:
-               smp_cmd_pairing_confirm(conn, skb);
+               reason = smp_cmd_pairing_confirm(conn, skb);
                break;
 
        case SMP_CMD_PAIRING_RANDOM:
-               smp_cmd_pairing_random(conn, skb);
+               reason = smp_cmd_pairing_random(conn, skb);
                break;
 
        case SMP_CMD_ENCRYPT_INFO: