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nuttx/wireless/bluetooth/bt_smp.c

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/****************************************************************************
* wireless/bluetooth/bt_smp.c
* Security Manager Protocol implementation.
*
* Copyright (C) 2018 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Ported from the Intel/Zephyr arduino101_firmware_source-v1.tar package
* where the code was released with a compatible 3-clause BSD license:
*
* Copyright (c) 2016, Intel Corporation
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stddef.h>
#include <errno.h>
#include <string.h>
#include <nuttx/wireless/bluetooth/bt_hci.h>
#include <nuttx/wireless/bluetooth/bt_core.h>
#include "bt_atomic.h"
#include "bt_hcicore.h"
#include "bt_keys.h"
#include "bt_conn.h"
#include "bt_l2cap.h"
#include "bt_smp.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define RECV_KEYS (BT_SMP_DIST_ID_KEY | BT_SMP_DIST_ENC_KEY)
#define SEND_KEYS (BT_SMP_DIST_ENC_KEY)
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
/****************************************************************************
* Private Types
****************************************************************************/
/* SMP channel specific context */
struct bt_smp_s
{
/* The connection this context is associated with */
FAR struct bt_conn_s *conn;
/* Commands that remote is allowed to send */
bt_atomic_t allowed_cmds;
/* If we're waiting for an encryption change event */
bool pending_encrypt;
/* Pairing Request PDU */
uint8_t preq[7];
/* Pairing Response PDU */
uint8_t prsp[7];
/* Pairing Confirm PDU */
uint8_t pcnf[16];
/* Local random number */
uint8_t prnd[16];
/* Remote random number */
uint8_t rrnd[16];
/* Temporary key */
uint8_t tk[16];
/* Local key distribution */
uint8_t local_dist;
/* Remote key distribution */
uint8_t remote_dist;
};
struct uint128_s
{
uint64_t a;
uint64_t b;
};
struct bt_smphandlers_s
{
CODE uint8_t(*func)(FAR struct bt_conn_s *conn, FAR struct bt_buf_s *buf);
uint8_t expect_len;
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
#ifdef CONFIG_DEBUG_WIRELESS_INFO
static const char *h(FAR const void *buf, size_t len);
#endif
static void xor_128(FAR const struct uint128_s *p,
FAR const struct uint128_s *q, FAR struct uint128_s *r);
static int le_encrypt(const uint8_t key[16], const uint8_t plaintext[16],
uint8_t enc_data[16]);
static int le_rand(FAR void *buf, size_t len);
static int smp_ah(FAR const uint8_t irk[16], FAR const uint8_t r[3],
FAR uint8_t out[3]);
static int smp_c1(FAR const uint8_t k[16], FAR const uint8_t r[16],
FAR const uint8_t preq[7], FAR const uint8_t pres[7],
FAR const bt_addr_le_t *ia, FAR const bt_addr_le_t *ra,
FAR uint8_t enc_data[16]);
static int smp_s1(const uint8_t k[16], const uint8_t r1[16],
const uint8_t r2[16], uint8_t out[16]);
static FAR struct bt_buf_s *bt_smp_create_pdu(FAR struct bt_conn_s *conn,
uint8_t op, size_t len);
static void send_err_rsp(FAR struct bt_conn_s *conn, uint8_t reason);
static int smp_init(struct bt_smp_s *smp);
static uint8_t smp_pairing_req(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf);
static uint8_t smp_pairing_rsp(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf);
static uint8_t smp_send_pairing_random(FAR struct bt_conn_s *conn);
static uint8_t smp_pairing_confirm(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf);
static uint8_t smp_pairing_random(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf);
static uint8_t smp_pairing_failed(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf);
static void bt_smp_distribute_keys(FAR struct bt_conn_s *conn);
static uint8_t smp_encrypt_info(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf);
static uint8_t smp_master_ident(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf);
static uint8_t smp_ident_info(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf);
static uint8_t smp_ident_addr_info(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf);
static uint8_t smp_security_request(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf);
static void bt_smp_receive(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf, FAR void *context,
uint16_t cid);
static void bt_smp_connected(FAR struct bt_conn_s *conn,
FAR void *context, uint16_t cid);
static void bt_smp_disconnected(FAR struct bt_conn_s *conn,
FAR void *context, uint16_t cid);
static void bt_smp_encrypt_change(FAR FAR struct bt_conn_s *conn,
FAR void *context, uint16_t cid);
#ifdef CONFIG_BLUETOOTH_SMP_SELFTEST
static void swap_buf(FAR const uint8_t *src, FAR uint8_t *dst,
uint16_t len);
static void swap_in_place(FAR uint8_t * buf, uint16_t len);
static int cmac_subkey(FAR const uint8_t *key, FAR uint8_t *k1,
FAR uint8_t *k2);
static void add_pad(FAR const uint8_t *in, FAR unsigned char *out,
int len);
static int bt_smp_aes_cmac(const uint8_t *key, const uint8_t *in,
size_t len, uint8_t *out);
static int aes_test(FAR const char *prefix, FAR const uint8_t *key,
FAR const uint8_t *m, uint16_t len,
FAR const uint8_t *mac);
static int smp_aes_cmac_test(void);
static int smp_self_test(void);
#else
# define smp_self_test() (0)
#endif
/****************************************************************************
* Private Data
****************************************************************************/
static struct bt_smp_s g_smp_pool[CONFIG_BLUETOOTH_MAX_CONN];
static const struct bt_smphandlers_s g_smp_handlers[] =
{
{
/* No op-code defined for 0x00 */
},
{
smp_pairing_req,
sizeof(struct bt_smp_pairing_s)
},
{
smp_pairing_rsp,
sizeof(struct bt_smp_pairing_s)
},
{
smp_pairing_confirm,
sizeof(struct bt_smp_pairing_confirm_s)
},
{
smp_pairing_random,
sizeof(struct bt_smp_pairing_random_s)
},
{
smp_pairing_failed,
sizeof(struct bt_smp_pairing_fail_s)
},
{
smp_encrypt_info,
sizeof(struct bt_smp_encrypt_info_s)
},
{
smp_master_ident,
sizeof(struct bt_smp_master_ident_s)
},
{
smp_ident_info,
sizeof(struct bt_smp_ident_info_s)
},
{
smp_ident_addr_info,
sizeof(struct bt_smp_ident_addr_info_s)
},
{
/* Signing Information - Not yet implemented */
},
{
smp_security_request,
sizeof(struct bt_smp_security_request_s)
}
};
#define NHANDLERS (sizeof(g_smp_handlers) / sizeof(struct bt_smphandlers_s))
#ifdef CONFIG_BLUETOOTH_SMP_SELFTEST
/* Test vectors are taken from RFC 4493
* https://tools.ietf.org/html/rfc4493
* Same mentioned in the Bluetooth Spec.
*/
static const uint8_t g_key[] =
{
0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c
};
static const uint8_t g_M[] =
{
0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10
};
static const uint8_t g_mac1[] =
{
0xbb, 0x1d, 0x69, 0x29, 0xe9, 0x59, 0x37, 0x28,
0x7f, 0xa3, 0x7d, 0x12, 0x9b, 0x75, 0x67, 0x46
};
static const uint8_t g_mac2[] =
{
0x07, 0x0a, 0x16, 0xb4, 0x6b, 0x4d, 0x41, 0x44,
0xf7, 0x9b, 0xdd, 0x9d, 0xd0, 0x4a, 0x28, 0x7c
};
static const uint8_t g_mac3[] =
{
0xdf, 0xa6, 0x67, 0x47, 0xde, 0x9a, 0xe6, 0x30,
0x30, 0xca, 0x32, 0x61, 0x14, 0x97, 0xc8, 0x27
};
static const uint8_t g_mac4[] =
{
0x51, 0xf0, 0xbe, 0xbf, 0x7e, 0x3b, 0x9d, 0x92,
0xfc, 0x49, 0x74, 0x17, 0x79, 0x36, 0x3c, 0xfe
};
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/* Helper for syslog parameters to convert from binary to hex.
* We declare multiple buffers so the helper can be used multiple times
* in a single syslog call.
*/
#ifdef CONFIG_DEBUG_WIRELESS_INFO
static const char *h(FAR const void *buf, size_t len)
{
static const char hex[] = "0123456789abcdef";
static char hexbufs[4][129];
static uint8_t curbuf;
FAR const uint8_t *b = buf;
FAR char *str;
size_t maxlen;
int i;
str = hexbufs[curbuf++];
curbuf %= ARRAY_SIZE(hexbufs);
maxlen = (sizeof(hexbufs[0]) - 1) / 2;
if (len > maxlen)
{
len = maxlen;
}
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;
}
#endif
static void xor_128(FAR const struct uint128_s *p,
FAR const struct uint128_s *q,
FAR struct uint128_s *r)
{
r->a = p->a ^ q->a;
r->b = p->b ^ q->b;
}
static int le_encrypt(const uint8_t key[16], const uint8_t plaintext[16],
uint8_t enc_data[16])
{
FAR struct bt_hci_cp_le_encrypt_s *cp;
FAR struct bt_hci_rp_le_encrypt_s *rp;
FAR struct bt_buf_s *buf, *rsp;
int err;
wlinfo("key %s plaintext %s\n", h(key, 16), h(plaintext, 16));
buf = bt_hci_cmd_create(BT_HCI_OP_LE_ENCRYPT, sizeof(*cp));
if (!buf)
{
return -ENOBUFS;
}
cp = bt_buf_extend(buf, sizeof(*cp));
memcpy(cp->key, key, sizeof(cp->key));
memcpy(cp->plaintext, plaintext, sizeof(cp->plaintext));
err = bt_hci_cmd_send_sync(BT_HCI_OP_LE_ENCRYPT, buf, &rsp);
if (err)
{
return err;
}
rp = (void *)rsp->data;
memcpy(enc_data, rp->enc_data, sizeof(rp->enc_data));
bt_buf_release(rsp);
wlinfo("enc_data %s\n", h(enc_data, 16));
return 0;
}
static int le_rand(FAR void *buf, size_t len)
{
FAR uint8_t *ptr = buf;
while (len > 0)
{
FAR struct bt_hci_rp_le_rand_s *rp;
FAR struct bt_buf_s *rsp;
size_t copy;
int err;
err = bt_hci_cmd_send_sync(BT_HCI_OP_LE_RAND, NULL, &rsp);
if (err)
{
wlerr("ERROR: HCI_LE_Random failed (%d)\n", err);
return err;
}
rp = (FAR void *)rsp->data;
copy = len;
if (copy > sizeof(rp->rand))
{
copy = sizeof(rp->rand);
}
memcpy(ptr, rp->rand, copy);
bt_buf_release(rsp);
len -= copy;
ptr += copy;
}
return 0;
}
static int smp_ah(FAR const uint8_t irk[16], FAR const uint8_t r[3],
FAR uint8_t out[3])
{
uint8_t res[16];
int err;
wlinfo("irk %s\n, r %s", h(irk, 16), h(r, 3));
/* r' = padding || r */
memcpy(res, r, 3);
memset(res + 3, 0, 13);
err = le_encrypt(irk, res, res);
if (err)
{
return err;
}
/* The output of the random address function ah is: ah(h, r) = e(k, r') mod
* 2^24 The output of the security function e is then truncated to 24 bits by
* taking the least significant 24 bits of the output of e as the result of
* ah.
*/
memcpy(out, res, 3);
return 0;
}
static int smp_c1(FAR const uint8_t k[16], FAR const uint8_t r[16],
FAR const uint8_t preq[7], FAR const uint8_t pres[7],
FAR const bt_addr_le_t *ia, FAR const bt_addr_le_t *ra,
FAR uint8_t enc_data[16])
{
uint8_t p1[16];
uint8_t p2[16];
int err;
wlinfo("k %s r %s\n", h(k, 16), h(r, 16));
wlinfo("ia %s ra %s\n", bt_addr_le_str(ia), bt_addr_le_str(ra));
wlinfo("preq %s pres %s\n", h(preq, 7), h(pres, 7));
/* pres, preq, rat and iat are concatenated to generate p1 */
p1[0] = ia->type;
p1[1] = ra->type;
memcpy(p1 + 2, preq, 7);
memcpy(p1 + 9, pres, 7);
wlinfo("p1 %s\n", h(p1, 16));
/* c1 = e(k, e(k, r XOR p1) XOR p2) */
/* Using enc_data as temporary output buffer */
xor_128((FAR struct uint128_s *)r, (FAR struct uint128_s *)p1,
(FAR struct uint128_s *)enc_data);
err = le_encrypt(k, enc_data, enc_data);
if (err)
{
return err;
}
/* ra is concatenated with ia and padding to generate p2 */
memcpy(p2, ra->val, 6);
memcpy(p2 + 6, ia->val, 6);
memset(p2 + 12, 0, 4);
wlinfo("p2 %s\n", h(p2, 16));
xor_128((FAR struct uint128_s *)enc_data, (FAR struct uint128_s *)p2, (FAR struct uint128_s *)enc_data);
return le_encrypt(k, enc_data, enc_data);
}
static int smp_s1(const uint8_t k[16], const uint8_t r1[16],
const uint8_t r2[16], uint8_t out[16])
{
/* The most significant 64-bits of r1 are discarded to generate r1' and the
* most significant 64-bits of r2 are discarded to generate r2'. r1' is
* concatenated with r2' to generate r' which is used as the 128-bit input
* parameter plaintextData to security function e: r' = r1' || r2'
*/
memcpy(out, r2, 8);
memcpy(out + 8, r1, 8);
/* s1(k, r1 , r2) = e(k, r') */
return le_encrypt(k, out, out);
}
static FAR struct bt_buf_s *bt_smp_create_pdu(FAR struct bt_conn_s *conn,
uint8_t op, size_t len)
{
FAR struct bt_smp_hdr_s *hdr;
FAR struct bt_buf_s *buf;
buf = bt_l2cap_create_pdu(conn);
if (!buf)
{
return NULL;
}
hdr = bt_buf_extend(buf, sizeof(*hdr));
hdr->code = op;
return buf;
}
static void send_err_rsp(FAR struct bt_conn_s *conn, uint8_t reason)
{
FAR struct bt_smp_pairing_fail_s *rsp;
FAR struct bt_buf_s *buf;
buf = bt_smp_create_pdu(conn, BT_SMP_CMD_PAIRING_FAIL, sizeof(*rsp));
if (!buf)
{
return;
}
rsp = bt_buf_extend(buf, sizeof(*rsp));
rsp->reason = reason;
bt_l2cap_send(conn, BT_L2CAP_CID_SMP, buf);
}
static int smp_init(struct bt_smp_s *smp)
{
/* Initialize SMP context */
memset(smp, 0, sizeof(*smp));
/* Generate local random number */
if (le_rand(smp->prnd, 16))
{
return BT_SMP_ERR_UNSPECIFIED;
}
wlinfo("prnd %s\n", h(smp->prnd, 16));
return 0;
}
static uint8_t smp_pairing_req(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf)
{
FAR struct bt_smp_pairing_s *req = (void *)buf->data;
FAR struct bt_smp_pairing_s *rsp;
FAR struct bt_buf_s *rsp_buf;
FAR struct bt_smp_s *smp = conn->smp;
uint8_t auth;
int ret;
wlinfo("\n");
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_extend(rsp_buf, sizeof(*rsp));
/* For JustWorks pairing simplify rsp parameters. TODO: needs to be reworked
* later on.
*/
auth = (req->auth_req & BT_SMP_AUTH_MASK);
auth &= ~(BT_SMP_AUTH_MITM | BT_SMP_AUTH_SC |
BT_SMP_AUTH_KEYPRESS);
rsp->auth_req = auth;
rsp->io_capability = BT_SMP_IO_NO_INPUT_OUTPUT;
rsp->oob_flag = BT_SMP_OOB_NOT_PRESENT;
rsp->max_key_size = req->max_key_size;
rsp->init_key_dist = (req->init_key_dist & RECV_KEYS);
rsp->resp_key_dist = (req->resp_key_dist & SEND_KEYS);
smp->local_dist = rsp->resp_key_dist;
smp->remote_dist = rsp->init_key_dist;
memset(smp->tk, 0, sizeof(smp->tk));
/* Store req/rsp for later use */
smp->preq[0] = BT_SMP_CMD_PAIRING_REQ;
memcpy(smp->preq + 1, req, sizeof(*req));
smp->prsp[0] = BT_SMP_CMD_PAIRING_RSP;
memcpy(smp->prsp + 1, rsp, sizeof(*rsp));
bt_l2cap_send(conn, BT_L2CAP_CID_SMP, rsp_buf);
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_PAIRING_CONFIRM);
return 0;
}
static uint8_t smp_send_pairing_confirm(FAR struct bt_conn_s *conn)
{
FAR struct bt_smp_pairing_confirm_s *req;
FAR struct bt_smp_s *smp = conn->smp;
FAR const bt_addr_le_t *ra;
FAR const bt_addr_le_t *ia;
FAR struct bt_buf_s *rsp_buf;
int err;
rsp_buf = bt_smp_create_pdu(conn, BT_SMP_CMD_PAIRING_CONFIRM, sizeof(*req));
if (!rsp_buf)
{
return BT_SMP_ERR_UNSPECIFIED;
}
req = bt_buf_extend(rsp_buf, sizeof(*req));
if (conn->role == BT_HCI_ROLE_MASTER)
{
ra = &conn->dst;
ia = &conn->src;
}
else
{
ra = &conn->src;
ia = &conn->dst;
}
err = smp_c1(smp->tk, smp->prnd, smp->preq, smp->prsp, ia, ra, req->val);
if (err)
{
bt_buf_release(rsp_buf);
return BT_SMP_ERR_UNSPECIFIED;
}
bt_l2cap_send(conn, BT_L2CAP_CID_SMP, rsp_buf);
return 0;
}
static uint8_t smp_pairing_rsp(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf)
{
struct bt_smp_pairing_s *rsp = (void *)buf->data;
struct bt_smp_s *smp = conn->smp;
wlinfo("\n");
if ((rsp->max_key_size > BT_SMP_MAX_ENC_KEY_SIZE) ||
(rsp->max_key_size < BT_SMP_MIN_ENC_KEY_SIZE))
{
return BT_SMP_ERR_ENC_KEY_SIZE;
}
smp->local_dist &= rsp->init_key_dist;
smp->remote_dist &= rsp->resp_key_dist;
/* Store rsp for later use */
smp->prsp[0] = BT_SMP_CMD_PAIRING_RSP;
memcpy(smp->prsp + 1, rsp, sizeof(*rsp));
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_PAIRING_CONFIRM);
return smp_send_pairing_confirm(conn);
}
static uint8_t smp_send_pairing_random(FAR struct bt_conn_s *conn)
{
FAR struct bt_smp_pairing_random_s *req;
FAR struct bt_buf_s *rsp_buf;
FAR struct bt_smp_s *smp = conn->smp;
rsp_buf = bt_smp_create_pdu(conn, BT_SMP_CMD_PAIRING_RANDOM, sizeof(*req));
if (!rsp_buf)
{
return BT_SMP_ERR_UNSPECIFIED;
}
req = bt_buf_extend(rsp_buf, sizeof(*req));
memcpy(req->val, smp->prnd, sizeof(req->val));
bt_l2cap_send(conn, BT_L2CAP_CID_SMP, rsp_buf);
return 0;
}
static uint8_t smp_pairing_confirm(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf)
{
struct bt_smp_pairing_confirm_s *req = (void *)buf->data;
struct bt_smp_s *smp = conn->smp;
wlinfo("\n");
memcpy(smp->pcnf, req->val, sizeof(smp->pcnf));
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_PAIRING_RANDOM);
if (conn->role == BT_HCI_ROLE_SLAVE)
{
return smp_send_pairing_confirm(conn);
}
return smp_send_pairing_random(conn);
}
static uint8_t smp_pairing_random(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf)
{
FAR struct bt_smp_pairing_random_s *req = (void *)buf->data;
FAR const bt_addr_le_t *ra;
FAR const bt_addr_le_t *ia;
FAR struct bt_smp_s *smp = conn->smp;
FAR struct bt_keys_s *keys;
uint8_t cfm[16];
int err;
wlinfo("\n");
memcpy(smp->rrnd, req->val, sizeof(smp->rrnd));
if (conn->role == BT_HCI_ROLE_MASTER)
{
ra = &conn->dst;
ia = &conn->src;
}
else
{
ra = &conn->src;
ia = &conn->dst;
}
err = smp_c1(smp->tk, smp->rrnd, smp->preq, smp->prsp, ia, ra, cfm);
if (err)
{
return BT_SMP_ERR_UNSPECIFIED;
}
wlinfo("pcnf %s cfm %s\n", h(smp->pcnf, 16), h(cfm, 16));
if (memcmp(smp->pcnf, cfm, sizeof(smp->pcnf)))
{
return BT_SMP_ERR_CONFIRM_FAILED;
}
if (conn->role == BT_HCI_ROLE_MASTER)
{
uint8_t stk[16];
/* No need to store master STK */
err = smp_s1(smp->tk, smp->rrnd, smp->prnd, stk);
if (err)
{
return BT_SMP_ERR_UNSPECIFIED;
}
/* Rand and EDiv are 0 for the STK */
if (bt_conn_le_start_encryption(conn, 0, 0, stk))
{
wlerr("ERROR: Failed to start encryption\n");
return BT_SMP_ERR_UNSPECIFIED;
}
smp->pending_encrypt = true;
return 0;
}
keys = bt_keys_get_type(BT_KEYS_SLAVE_LTK, &conn->dst);
if (keys == NULL)
{
wlerr("ERROR: Unable to create new keys\n");
return BT_SMP_ERR_UNSPECIFIED;
}
err = smp_s1(smp->tk, smp->prnd, smp->rrnd, keys->slave_ltk.val);
if (err)
{
bt_keys_clear(keys, BT_KEYS_SLAVE_LTK);
return BT_SMP_ERR_UNSPECIFIED;
}
/* Rand and EDiv are 0 for the STK */
keys->slave_ltk.rand = 0;
keys->slave_ltk.ediv = 0;
wlinfo("generated STK %s\n", h(keys->slave_ltk.val, 16));
smp->pending_encrypt = true;
smp_send_pairing_random(conn);
return 0;
}
static uint8_t smp_pairing_failed(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf)
{
struct bt_smp_pairing_fail_s *req = (void *)buf->data;
struct bt_smp_s *smp = conn->smp;
wlerr("ERROR: reason 0x%x\n", req->reason);
UNUSED(req);
bt_atomic_set(&smp->allowed_cmds, 0);
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_PAIRING_FAIL);
if (conn->role == BT_HCI_ROLE_MASTER)
{
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_SECURITY_REQUEST);
}
else
{
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_PAIRING_REQ);
}
/* return no error to avoid sending Pairing Failed in response */
return 0;
}
static void bt_smp_distribute_keys(FAR struct bt_conn_s *conn)
{
FAR struct bt_smp_s *smp = conn->smp;
FAR struct bt_keys_s *keys;
FAR struct bt_buf_s *buf;
keys = bt_keys_get_addr(&conn->dst);
if (!keys)
{
wlerr("ERROR: Unable to look up keys for %s\n", bt_addr_le_str(&conn->dst));
return;
}
if (!smp->local_dist)
{
bt_keys_clear(keys, BT_KEYS_ALL);
return;
}
if (smp->local_dist & BT_SMP_DIST_ENC_KEY)
{
struct bt_smp_encrypt_info_s *info;
struct bt_smp_master_ident_s *ident;
bt_keys_add_type(keys, BT_KEYS_SLAVE_LTK);
le_rand(keys->slave_ltk.val, sizeof(keys->slave_ltk.val));
le_rand(&keys->slave_ltk.rand, sizeof(keys->slave_ltk.rand));
le_rand(&keys->slave_ltk.ediv, sizeof(keys->slave_ltk.ediv));
buf = bt_smp_create_pdu(conn, BT_SMP_CMD_ENCRYPT_INFO,
sizeof(struct bt_smp_encrypt_info_s));
if (!buf)
{
wlerr("ERROR: Unable to allocate Encrypt Info buffer\n");
return;
}
info = bt_buf_extend(buf, sizeof(struct bt_smp_encrypt_info_s));
memcpy(info->ltk, keys->slave_ltk.val, sizeof(info->ltk));
bt_l2cap_send(conn, BT_L2CAP_CID_SMP, buf);
buf = bt_smp_create_pdu(conn, BT_SMP_CMD_MASTER_IDENT,
sizeof(struct bt_smp_master_ident_s));
if (!buf)
{
wlerr("ERROR: Unable to allocate Master Ident buffer\n");
return;
}
ident = bt_buf_extend(buf, sizeof(struct bt_smp_master_ident_s));
ident->rand = keys->slave_ltk.rand;
ident->ediv = keys->slave_ltk.ediv;
bt_l2cap_send(conn, BT_L2CAP_CID_SMP, buf);
}
}
static uint8_t smp_encrypt_info(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf)
{
FAR struct bt_smp_encrypt_info_s *req = (void *)buf->data;
FAR struct bt_smp_s *smp = conn->smp;
FAR struct bt_keys_s *keys;
wlinfo("\n");
keys = bt_keys_get_type(BT_KEYS_LTK, &conn->dst);
if (!keys)
{
wlerr("ERROR: Unable to get keys for %s\n", bt_addr_le_str(&conn->dst));
return BT_SMP_ERR_UNSPECIFIED;
}
memcpy(keys->ltk.val, req->ltk, 16);
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_MASTER_IDENT);
return 0;
}
static uint8_t smp_master_ident(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf)
{
FAR struct bt_smp_master_ident_s *req = (void *)buf->data;
FAR struct bt_smp_s *smp = conn->smp;
FAR struct bt_keys_s *keys;
wlinfo("\n");
keys = bt_keys_get_type(BT_KEYS_LTK, &conn->dst);
if (!keys)
{
wlerr("ERROR: Unable to get keys for %s\n", bt_addr_le_str(&conn->dst));
return BT_SMP_ERR_UNSPECIFIED;
}
keys->ltk.ediv = req->ediv;
keys->ltk.rand = req->rand;
if (conn->role == BT_HCI_ROLE_MASTER)
{
smp->remote_dist &= ~BT_SMP_DIST_ENC_KEY;
if (!smp->remote_dist)
{
bt_smp_distribute_keys(conn);
return 0;
}
}
if (smp->remote_dist & BT_SMP_DIST_ID_KEY)
{
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_IDENT_INFO);
}
return 0;
}
static uint8_t smp_ident_info(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf)
{
FAR struct bt_smp_ident_info_s *req = (FAR void *)buf->data;
FAR struct bt_smp_s *smp = conn->smp;
FAR struct bt_keys_s *keys;
wlinfo("\n");
keys = bt_keys_get_type(BT_KEYS_IRK, &conn->dst);
if (!keys)
{
wlerr("ERROR: Unable to get keys for %s\n", bt_addr_le_str(&conn->dst));
return BT_SMP_ERR_UNSPECIFIED;
}
memcpy(keys->irk.val, req->irk, 16);
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_IDENT_ADDR_INFO);
return 0;
}
static uint8_t smp_ident_addr_info(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf)
{
FAR struct bt_smp_ident_addr_info_s *req = (void *)buf->data;
FAR struct bt_smp_s *smp = conn->smp;
FAR struct bt_keys_s *keys;
wlinfo("identity %s\n", bt_addr_le_str(&req->addr));
if (!bt_addr_le_is_identity(&req->addr))
{
wlerr("ERROR: Invalid identity %s for %s\n",
bt_addr_le_str(&req->addr), bt_addr_le_str(&conn->dst));
return BT_SMP_ERR_INVALID_PARAMS;
}
keys = bt_keys_get_type(BT_KEYS_IRK, &conn->dst);
if (!keys)
{
wlerr("ERROR: Unable to get keys for %s\n", bt_addr_le_str(&conn->dst));
return BT_SMP_ERR_UNSPECIFIED;
}
if (bt_addr_le_is_rpa(&conn->dst))
{
bt_addr_copy(&keys->irk.rpa, (bt_addr_t *) & conn->dst.val);
bt_addr_le_copy(&keys->addr, &req->addr);
bt_addr_le_copy(&conn->dst, &req->addr);
}
if (conn->role == BT_HCI_ROLE_MASTER)
{
smp->remote_dist &= ~BT_SMP_DIST_ID_KEY;
if (!smp->remote_dist)
{
bt_smp_distribute_keys(conn);
}
}
return 0;
}
static uint8_t smp_security_request(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf)
{
FAR struct bt_smp_security_request_s *req = (FAR void *)buf->data;
FAR struct bt_keys_s *keys;
uint8_t auth;
wlinfo("\n");
keys = bt_keys_find(BT_KEYS_LTK, &conn->dst);
if (!keys)
{
goto pair;
}
auth = req->auth_req & BT_SMP_AUTH_MASK;
if (auth & (BT_SMP_AUTH_MITM | BT_SMP_AUTH_SC))
{
wlwarn("Unsupported auth requirements: 0x%x, repairing", auth);
goto pair;
}
if (bt_conn_le_start_encryption(conn, keys->ltk.rand, keys->ltk.ediv,
keys->ltk.val) < 0)
{
return BT_SMP_ERR_UNSPECIFIED;
}
return 0;
pair:
if (bt_smp_send_pairing_req(conn) < 0)
{
return BT_SMP_ERR_UNSPECIFIED;
}
return 0;
}
static void bt_smp_receive(FAR struct bt_conn_s *conn,
FAR struct bt_buf_s *buf, FAR void *context,
uint16_t cid)
{
FAR struct bt_smp_hdr_s *hdr = (FAR void *)buf->data;
FAR struct bt_smp_s *smp = conn->smp;
uint8_t err;
if (buf->len < sizeof(*hdr))
{
wlerr("ERROR: Too small SMP PDU received\n");
goto done;
}
wlinfo("Received SMP code 0x%02x len %u\n", hdr->code, buf->len);
bt_buf_consume(buf, sizeof(*hdr));
if (hdr->code >= NHANDLERS || !g_smp_handlers[hdr->code].func)
{
wlwarn("Unhandled SMP code 0x%02x\n", hdr->code);
err = BT_SMP_ERR_CMD_NOTSUPP;
}
else
{
if (!bt_atomic_testclrbit(&smp->allowed_cmds, hdr->code))
{
wlwarn("Unexpected SMP code 0x%02x\n", hdr->code);
goto done;
}
if (buf->len != g_smp_handlers[hdr->code].expect_len)
{
wlerr("ERROR: Invalid len %u for code 0x%02x\n", buf->len, hdr->code);
err = BT_SMP_ERR_INVALID_PARAMS;
}
else
{
err = g_smp_handlers[hdr->code].func(conn, buf);
}
}
if (err)
{
send_err_rsp(conn, err);
bt_atomic_set(&smp->allowed_cmds, 0);
if (conn->role == BT_HCI_ROLE_MASTER)
{
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_SECURITY_REQUEST);
}
else
{
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_PAIRING_REQ);
}
}
done:
bt_buf_release(buf);
}
static void bt_smp_connected(FAR struct bt_conn_s *conn, FAR void *context,
uint16_t cid)
{
int i;
wlinfo("conn %p handle %u\n", conn, conn->handle);
for (i = 0; i < CONFIG_BLUETOOTH_MAX_CONN; i++)
{
struct bt_smp_s *smp = &g_smp_pool[i];
if (smp->conn)
{
continue;
}
smp->conn = conn;
conn->smp = smp;
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_PAIRING_FAIL);
if (conn->role == BT_HCI_ROLE_MASTER)
{
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_SECURITY_REQUEST);
}
else
{
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_PAIRING_REQ);
}
return;
}
wlerr("ERROR: No available SMP context for conn %p\n", conn);
}
static void bt_smp_disconnected(FAR struct bt_conn_s *conn,
FAR void *context, uint16_t cid)
{
struct bt_smp_s *smp = conn->smp;
if (!smp)
{
return;
}
wlinfo("conn %p handle %u\n", conn, conn->handle);
conn->smp = NULL;
memset(smp, 0, sizeof(*smp));
}
static void bt_smp_encrypt_change(FAR FAR struct bt_conn_s *conn,
FAR void *context, uint16_t cid)
{
struct bt_smp_s *smp = conn->smp;
wlinfo("conn %p handle %u encrypt 0x%02x\n", conn, conn->handle,
conn->encrypt);
if (!smp || !conn->encrypt)
{
return;
}
if (!smp->pending_encrypt)
{
return;
}
smp->pending_encrypt = false;
if (smp->remote_dist & BT_SMP_DIST_ENC_KEY)
{
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_ENCRYPT_INFO);
}
else if (smp->remote_dist & BT_SMP_DIST_ID_KEY)
{
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_IDENT_INFO);
}
/* Slave distributes it's keys first */
if (conn->role == BT_HCI_ROLE_MASTER && smp->remote_dist)
{
return;
}
bt_smp_distribute_keys(conn);
}
#if defined(CONFIG_BLUETOOTH_SMP_SELFTEST)
/* spaw octets for LE encrypt */
static void swap_buf(FAR const uint8_t *src, FAR uint8_t *dst, uint16_t len)
{
int i;
for (i = 0; i < len; i++)
{
dst[len - 1 - i] = src[i];
}
}
static void swap_in_place(FAR uint8_t * buf, uint16_t len)
{
int i;
int j;
for (i = 0, j = len - 1; i < j; i++, j--)
{
uint8_t tmp = buf[i];
buf[i] = buf[j];
buf[j] = tmp;
}
}
/* 1 bit left shift */
static void array_shift(FAR const uint8_t *in, FAR uint8_t *out)
{
uint8_t overflow = 0;
for (int i = 15; i >= 0; i--)
{
out[i] = in[i] << 1;
/* previous byte */
out[i] |= overflow;
overflow = in[i] & 0x80 ? 1 : 0;
}
}
/* CMAC subkey generation algorithm */
static int cmac_subkey(FAR const uint8_t *key, FAR uint8_t *k1,
FAR uint8_t *k2)
{
const uint8_t rb[16] =
{
[0 ... 14] = 0x00,
[15] = 0x87,
};
uint8_t zero[16] = { 0 };
uint8_t *tmp = zero;
uint8_t l[16];
int err;
/* L := AES-128(K, const_Zero) */
err = le_encrypt(key, zero, tmp);
if (err)
{
return err;
}
swap_buf(tmp, l, 16);
wlinfo("l %s\n", h(l, 16));
/* if MSB(L) == 0 K1 = L << 1 */
if (!(l[0] & 0x80))
{
array_shift(l, k1);
/* else K1 = (L << 1) XOR rb */
}
else
{
array_shift(l, k1);
xor_128((FAR struct uint128_s *)k1, (FAR struct uint128_s *)rb, (FAR struct uint128_s *)k1);
}
/* if MSB(K1) == 0 K2 = K1 << 1 */
if (!(k1[0] & 0x80))
{
array_shift(k1, k2);
/* else K2 = (K1 << 1) XOR rb */
}
else
{
array_shift(k1, k2);
xor_128((FAR struct uint128_s *)k2, (struct uint128_s *FAR )rb, (FAR struct uint128_s *)k2);
}
return 0;
}
/* padding(x) = x || 10^i where i is 128 - 8 * r - 1 */
static void add_pad(FAR const uint8_t *in, FAR unsigned char *out, int len)
{
memset(out, 0, 16);
memcpy(out, in, len);
out[len] = 0x80;
}
/* Cypher based Message Authentication Code (CMAC) with AES 128 bit
*
* Input : key ( 128-bit key )
* : in ( message to be authenticated )
* : len ( length of the message in octets )
* Output : out ( message authentication code )
*/
static int bt_smp_aes_cmac(FAR const uint8_t *key, FAR const uint8_t *in,
size_t len, FAR uint8_t *out)
{
uint8_t k1[16];
uint8_t k2[16];
uint8_t last_block[16];
FAR uint8_t *pad_block = last_block;
uint8_t key_s[16];
FAR uint8_t *x;
FAR uint8_t *y;
uint8_t flag;
uint8_t n;
int err;
swap_buf(key, key_s, 16);
/* (K1,K2) = Generate_Subkey(K) */
err = cmac_subkey(key_s, k1, k2);
if (err)
{
return err;
}
wlinfo("key %s subkeys k1 %s k2 %s\n", h(key, 16), h(k1, 16), h(k2, 16));
/* the number of blocks, n, is calculated, the block length is 16 bytes n =
* ceil(len/const_Bsize)
*/
n = (len + 15) / 16;
/* check input length, flag indicate completed blocks */
if (n == 0)
{
/* if length is 0, the number of blocks to be processed shall be 1,and
* the flag shall be marked as not-complete-block false.
*/
n = 1;
flag = 0;
}
else
{
if ((len % 16) == 0)
{
/* complete blocks */
flag = 1;
}
else
{
/* last block is not complete */
flag = 0;
}
}
wlinfo("len %u n %u flag %u\n", len, n, flag);
/* if flag is true then M_last = M_n XOR K1 */
if (flag)
{
xor_128((FAR struct uint128_s *)&in[16 * (n - 1)],
(FAR struct uint128_s *)k1,
(FAR struct uint128_s *)last_block);
/* else M_last = padding(M_n) XOR K2 */
}
else
{
add_pad(&in[16 * (n - 1)], pad_block, len % 16);
xor_128((FAR struct uint128_s *)pad_block,
(FAR struct uint128_s *)k2,
(FAR struct uint128_s *)last_block);
}
/* Reuse k1 and k2 buffers */
x = k1;
y = k2;
/* Zeroing x */
memset(x, 0, 16);
/* Rhe basic CBC-MAC is applied to M_1,...,M_{n-1},M_last */
for (int i = 0; i < n - 1; i++)
{
/* Y = X XOR M_i */
xor_128((FAR struct uint128_s *)x,
(FAR struct uint128_s *)&in[i * 16],
(FAR struct uint128_s *) y);
swap_in_place(y, 16);
/* X = AES-128(K,Y) */
err = le_encrypt(key_s, y, x);
if (err)
{
return err;
}
swap_in_place(x, 16);
}
/* Y = M_last XOR X */
xor_128((FAR struct uint128_s *)x,
(FAR struct uint128_s *)last_block,
(FAR struct uint128_s *)y);
swap_in_place(y, 16);
/* T = AES-128(K,Y) */
err = le_encrypt(key_s, y, out);
swap_in_place(out, 16);
return err;
}
static int aes_test(const char *prefix, const uint8_t *key, const uint8_t *m,
uint16_t len, const uint8_t * mac)
{
uint8_t out[16];
wlinfo("%s: AES CMAC of message with len %u\n", prefix, len);
bt_smp_aes_cmac(key, m, len, out);
if (!memcmp(out, mac, 16))
{
wlinfo("%s: Success\n", prefix);
}
else
{
wlerr("ERROR: %s: Failed\n", prefix);
return -1;
}
return 0;
}
static int smp_aes_cmac_test(void)
{
int err;
err = aes_test("Test aes-cmac0", g_key, g_M, 0, g_mac1);
if (err)
{
return err;
}
err = aes_test("Test aes-cmac16", g_key, g_M, 16, g_mac2);
if (err)
{
return err;
}
err = aes_test("Test aes-cmac40", g_key, g_M, 40, g_mac3);
if (err)
{
return err;
}
err = aes_test("Test aes-cmac64", g_key, g_M, 64, g_mac4);
if (err)
{
return err;
}
return 0;
}
static int smp_self_test(void)
{
int err;
err = smp_aes_cmac_test();
if (err)
{
wlerr("ERROR: SMP AES-CMAC self tests failed\n");
return err;
}
return 0;
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
int bt_smp_initialize(void)
{
static struct bt_l2cap_chan_s chan =
{
.cid = BT_L2CAP_CID_SMP,
.receive = bt_smp_receive,
.connected = bt_smp_connected,
.disconnected = bt_smp_disconnected,
.encrypt_change = bt_smp_encrypt_change,
};
bt_l2cap_chan_register(&chan);
return smp_self_test();
}
int bt_smp_send_security_req(FAR struct bt_conn_s *conn)
{
struct bt_smp_security_request_s *req;
FAR struct bt_buf_s *req_buf;
wlinfo("\n");
req_buf = bt_smp_create_pdu(conn, BT_SMP_CMD_SECURITY_REQUEST,
sizeof(struct bt_smp_security_request_s));
if (!req_buf)
{
return -ENOBUFS;
}
req = bt_buf_extend(req_buf, sizeof(struct bt_smp_security_request_s));
req->auth_req = BT_SMP_AUTH_BONDING;
bt_l2cap_send(conn, BT_L2CAP_CID_SMP, req_buf);
return 0;
}
int bt_smp_send_pairing_req(FAR struct bt_conn_s *conn)
{
FAR struct bt_smp_s *smp = conn->smp;
FAR struct bt_smp_pairing_s *req;
FAR struct bt_buf_s *req_buf;
wlinfo("\n");
if (smp_init(smp))
{
return -ENOBUFS;
}
req_buf = bt_smp_create_pdu(conn, BT_SMP_CMD_PAIRING_REQ, sizeof(*req));
if (!req_buf)
{
return -ENOBUFS;
}
req = bt_buf_extend(req_buf, sizeof(*req));
/* For JustWorks pairing simplify req parameters. TODO: needs to be reworked
* later on
*/
req->auth_req = BT_SMP_AUTH_BONDING;
req->io_capability = BT_SMP_IO_NO_INPUT_OUTPUT;
req->oob_flag = BT_SMP_OOB_NOT_PRESENT;
req->max_key_size = BT_SMP_MAX_ENC_KEY_SIZE;
req->init_key_dist = SEND_KEYS;
req->resp_key_dist = RECV_KEYS;
smp->local_dist = SEND_KEYS;
smp->remote_dist = RECV_KEYS;
memset(smp->tk, 0, sizeof(smp->tk));
/* Store req for later use */
smp->preq[0] = BT_SMP_CMD_PAIRING_REQ;
memcpy(smp->preq + 1, req, sizeof(*req));
bt_l2cap_send(conn, BT_L2CAP_CID_SMP, req_buf);
bt_atomic_setbit(&smp->allowed_cmds, BT_SMP_CMD_PAIRING_RSP);
return 0;
}
bool bt_smp_irk_matches(FAR const uint8_t irk[16], FAR const bt_addr_t *addr)
{
uint8_t hash[3];
int err;
wlinfo("IRK %s bdaddr %s", h(irk, 16), bt_addr_str(addr));
err = smp_ah(irk, addr->val + 3, hash);
if (err)
{
return false;
}
return !memcmp(addr->val, hash, 3);
}
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