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@xxxxxxxxxxxxx>
---
include/net/bluetooth/smp.h | 17 ++++++
net/bluetooth/hci_event.c | 1 +
net/bluetooth/smp.c | 118 ++++++++++++++++++++++--------------------
3 files changed, 80 insertions(+), 56 deletions(-)
diff --git a/include/net/bluetooth/smp.h b/include/net/bluetooth/smp.h
index 36bdd6e..111853a 100644
--- a/include/net/bluetooth/smp.h
+++ b/include/net/bluetooth/smp.h
@@ -38,6 +38,23 @@ struct smp_cmd_pairing {
__u8 resp_key_dist;
} __packed;
+#define SMP_IO_DISPLAY_ONLY 0x00
+#define SMP_IO_DISPLAY_YESNO 0x01
+#define SMP_IO_KEYBOARD_ONLY 0x02
+#define SMP_IO_NO_INPUT_OUTPUT 0x03
+#define SMP_IO_KEYBOARD_DISPLAY 0x04
+
+#define SMP_OOB_NOT_PRESENT 0x00
+#define SMP_OOB_PRESENT 0x01
+
+#define SMP_DIST_ENC_KEY 0x01
+#define SMP_DIST_ID_KEY 0x02
+#define SMP_DIST_SIGN 0x04
+
+#define SMP_AUTH_NONE 0x00
+#define SMP_AUTH_BONDING 0x01
+#define SMP_AUTH_MITM 0x04
+
#define SMP_CMD_PAIRING_CONFIRM 0x03
struct smp_cmd_pairing_confirm {
__u8 confirm_val[16];
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index fece2ee..99c75f4 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -1509,6 +1509,7 @@ 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 35ceba6..ddd8783 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -186,7 +186,31 @@ static void smp_send_cmd(struct l2cap_conn *conn, u8 code, u16 len, void *data)
hci_send_acl(conn->hcon, skb, 0);
}
-static void smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
+static __u8 seclevel_to_authreq(__u8 level)
+{
+ switch (level) {
+ case BT_SECURITY_MEDIUM:
+ return SMP_AUTH_BONDING;
+
+ case BT_SECURITY_HIGH:
+ return SMP_AUTH_BONDING | SMP_AUTH_MITM;
+
+ default:
+ return SMP_AUTH_NONE;
+ }
+}
+
+static void build_pairing_cmd(struct l2cap_conn *conn, struct smp_cmd_pairing *cmd, __u8 authreq)
+{
+ cmd->io_capability = SMP_IO_NO_INPUT_OUTPUT;
+ cmd->oob_flag = SMP_OOB_NOT_PRESENT;
+ cmd->max_key_size = 16;
+ cmd->init_key_dist = 0x00;
+ cmd->resp_key_dist = 0x00;
+ cmd->auth_req = authreq;
+}
+
+static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
{
struct smp_cmd_pairing *rp = (void *) skb->data;
@@ -196,12 +220,11 @@ 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 &= 0x05;
+ 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));
@@ -210,9 +233,11 @@ static void smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
memcpy(&conn->pres[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;
@@ -222,28 +247,31 @@ static void smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
BT_DBG("conn %p", conn);
+ skb_pull(skb, sizeof(*rp));
+
/* Just works */
memset(conn->tk, 0, sizeof(conn->tk));
conn->pres[0] = SMP_CMD_PAIRING_RSP;
memcpy(&conn->pres[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->pres, 0,
conn->src, 0, 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;
@@ -264,20 +292,22 @@ static void smp_cmd_pairing_confirm(struct l2cap_conn *conn, struct sk_buff *skb
ret = smp_rand(conn->prnd);
if (ret)
- return;
+ return SMP_UNSPECIFIED;
ret = smp_c1(tfm, conn->tk, conn->prnd, conn->preq, conn->pres,
0, 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;
@@ -296,19 +326,15 @@ static void smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
ret = smp_c1(tfm, conn->tk, random, conn->preq, conn->pres, 0,
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, 16) != 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) {
@@ -331,9 +357,11 @@ static void smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
hex_dump_to_buffer(key, sizeof(key), 16, 1, buf, sizeof(buf), 0);
BT_DBG("key %s", buf);
}
+
+ 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;
@@ -342,17 +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 & 0x05;
+ 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));
@@ -360,22 +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 seclevel)
-{
- switch (seclevel) {
- case BT_SECURITY_MEDIUM:
- /* Encrypted, no MITM protection */
- return HCI_AT_NO_BONDING_MITM;
-
- case BT_SECURITY_HIGH:
- /* Bonding, MITM protection */
- return HCI_AT_GENERAL_BONDING_MITM;
- default:
- return HCI_AT_NO_BONDING;
- }
+ return 0;
}
int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level)
@@ -401,13 +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));
@@ -440,26 +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:
--
1.7.4
--
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