michaelh/zephyr
1
0
Fork 0
Code Releases Activity

Bluetooth: SMP: Add local random number generation support

Browse source 
The SMP procedures require us to establish a local random number. Use
the HCI_LE_Rand command to generate the necessary 16 bytes (the
command needs to be called twice since it only returns 8 bytes at a
time). Store this number in the SMP context.

To help debugging with various crypto related values add a local h()
helper function for printk/BT_DBG to do hexadecimal conversion.

Change-Id: Id3e8793a77ac635023b3cc3a94e8679170455870
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This commit is contained in:
Johan Hedberg 2015-05-19 21:12:30 +03:00 • committed by Anas Nashif
commit a648bbe9a1
3 changed files with 101 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

6
include/bluetooth/hci.h
View file

@ -238,6 +238,12 @@ struct bt_hci_rp_le_encrypt {
uint8_t enc_data[16];
} PACK_STRUCT;
#define BT_HCI_OP_LE_RAND BT_OP(BT_OGF_LE, 0x0018)
struct bt_hci_rp_le_rand {
uint8_t status;
uint8_t rand[8];
} PACK_STRUCT;
/* Event definitions */
#define BT_HCI_EVT_DISCONN_COMPLETE 0x05

2
net/bluetooth/conn.h
View file

@ -49,6 +49,8 @@ struct bt_conn_att {
/* SMP channel specific context */
struct bt_conn_smp {
/* Local random number */
uint8_t prnd[16];
};
struct bt_conn {

99
net/bluetooth/smp.c
View file

@ -35,6 +35,9 @@
#include <nanokernel.h>
#include <stddef.h>
#include <errno.h>
#include <string.h>
#include <misc/util.h>
#include <bluetooth/hci.h>
#include <bluetooth/bluetooth.h>
@ -44,11 +47,71 @@
#include "l2cap.h"
#include "smp.h"
#if !defined(CONFIG_BLUETOOTH_DEBUG_SMP)
#if defined(CONFIG_BLUETOOTH_DEBUG_SMP)
/* Helper for printk parameters to convert from binary to hex.
* We declare multiple buffers so the helper can be used multiple times
* in a single printk call.
*/
static const char *h(const void *buf, size_t len)
{
static const char hex[] = "0123456789abcdef";
static char hexbufs[4][129];
static uint8_t curbuf;
const uint8_t *b = buf;
char *str;
int i;
str = hexbufs[curbuf++];
curbuf %= ARRAY_SIZE(hexbufs);
len = min(len, (sizeof(hexbufs[0]) - 1) / 2);
for (i = 0; i < len; i++) {
str[i * 2] = hex[b[i] >> 4];
str[i * 2 + 1] = hex[b[i] & 0xf];
}
str[i * 2] = '\0';
return str;
}
#else
#undef BT_DBG
#define BT_DBG(fmt, ...)
#endif
static int le_rand(uint8_t rand[16])
{
struct bt_hci_rp_le_rand *rp;
struct bt_buf *rsp;
int err;
/* First 8 bytes */
err = bt_hci_cmd_send_sync(BT_HCI_OP_LE_RAND, NULL, &rsp);
if (err) {
return err;
}
rp = (void *)rsp->data;
memcpy(rand, rp->rand, 8);
bt_buf_put(rsp);
/* Second 8 bytes */
err = bt_hci_cmd_send_sync(BT_HCI_OP_LE_RAND, NULL, &rsp);
if (err) {
return err;
}
rp = (void *)rsp->data;
memcpy(rand + 8, rp->rand, 8);
bt_buf_put(rsp);
BT_DBG("rand %s\n", h(rand, 16));
return 0;
}
struct bt_buf *bt_smp_create_pdu(struct bt_conn *conn, uint8_t op, size_t len)
{
struct bt_smp_hdr *hdr;
@ -79,26 +142,50 @@ static void send_err_rsp(struct bt_conn *conn, uint8_t reason)
bt_conn_send(conn, buf);
}
static int smp_init(struct bt_conn_smp *smp)
{
/* Initialize SMP context */
memset(smp, 0, sizeof(*smp));
/* Generate local random number */
if (le_rand(smp->prnd)) {
return BT_SMP_ERR_UNSPECIFIED;
}
BT_DBG("prnd %s\n", h(smp->prnd, 16));
return 0;
}
static int smp_pairing_req(struct bt_conn *conn, struct bt_buf *buf)
{
struct bt_smp_pairing *req = (void *)buf->data;
struct bt_smp_pairing *rsp;
struct bt_buf *rsp_buf;
struct bt_conn_smp *smp = &conn->smp;
int ret;
BT_DBG("\n");
if (buf->len != sizeof(*req))
if (buf->len != sizeof(*req)) {
return BT_SMP_ERR_INVALID_PARAMS;
rsp_buf = bt_smp_create_pdu(conn, BT_SMP_CMD_PAIRING_RSP, sizeof(*rsp));
if (!rsp_buf)
return BT_SMP_ERR_UNSPECIFIED;
}
if ((req->max_key_size > BT_SMP_MAX_ENC_KEY_SIZE) ||
(req->max_key_size < BT_SMP_MIN_ENC_KEY_SIZE)) {
return BT_SMP_ERR_ENC_KEY_SIZE;
}
ret = smp_init(smp);
if (ret) {
return ret;
}
rsp_buf = bt_smp_create_pdu(conn, BT_SMP_CMD_PAIRING_RSP, sizeof(*rsp));
if (!rsp_buf) {
return BT_SMP_ERR_UNSPECIFIED;
}
rsp = bt_buf_add(rsp_buf, sizeof(*rsp));
/* For JustWorks pairing simplify rsp parameters.