diff options
Diffstat (limited to 'net/bluetooth/smp.c')
-rw-r--r-- | net/bluetooth/smp.c | 418 |
1 files changed, 352 insertions, 66 deletions
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c index 45007362683b..f886bcae1b7e 100644 --- a/net/bluetooth/smp.c +++ b/net/bluetooth/smp.c @@ -78,6 +78,70 @@ static int smp_e(struct crypto_blkcipher *tfm, const u8 *k, u8 *r) return err; } +static int smp_ah(struct crypto_blkcipher *tfm, u8 irk[16], u8 r[3], u8 res[3]) +{ + u8 _res[16], k[16]; + int err; + + /* r' = padding || r */ + memset(_res, 0, 13); + _res[13] = r[2]; + _res[14] = r[1]; + _res[15] = r[0]; + + swap128(irk, k); + err = smp_e(tfm, k, _res); + if (err) { + BT_ERR("Encrypt error"); + 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. + */ + res[0] = _res[15]; + res[1] = _res[14]; + res[2] = _res[13]; + + return 0; +} + +bool smp_irk_matches(struct crypto_blkcipher *tfm, u8 irk[16], + bdaddr_t *bdaddr) +{ + u8 hash[3]; + int err; + + BT_DBG("RPA %pMR IRK %*phN", bdaddr, 16, irk); + + err = smp_ah(tfm, irk, &bdaddr->b[3], hash); + if (err) + return false; + + return !memcmp(bdaddr->b, hash, 3); +} + +int smp_generate_rpa(struct crypto_blkcipher *tfm, u8 irk[16], bdaddr_t *rpa) +{ + int err; + + get_random_bytes(&rpa->b[3], 3); + + rpa->b[5] &= 0x3f; /* Clear two most significant bits */ + rpa->b[5] |= 0x40; /* Set second most significant bit */ + + err = smp_ah(tfm, irk, &rpa->b[3], rpa->b); + if (err < 0) + return err; + + BT_DBG("RPA %pMR", rpa); + + return 0; +} + static int smp_c1(struct crypto_blkcipher *tfm, u8 k[16], u8 r[16], u8 preq[7], u8 pres[7], u8 _iat, bdaddr_t *ia, u8 _rat, bdaddr_t *ra, u8 res[16]) @@ -203,31 +267,45 @@ static void build_pairing_cmd(struct l2cap_conn *conn, struct smp_cmd_pairing *req, struct smp_cmd_pairing *rsp, __u8 authreq) { - u8 dist_keys = 0; + struct smp_chan *smp = conn->smp_chan; + struct hci_conn *hcon = conn->hcon; + struct hci_dev *hdev = hcon->hdev; + u8 local_dist = 0, remote_dist = 0; if (test_bit(HCI_PAIRABLE, &conn->hcon->hdev->dev_flags)) { - dist_keys = SMP_DIST_ENC_KEY; + local_dist = SMP_DIST_ENC_KEY; + remote_dist = SMP_DIST_ENC_KEY; authreq |= SMP_AUTH_BONDING; } else { authreq &= ~SMP_AUTH_BONDING; } + if (test_bit(HCI_RPA_RESOLVING, &hdev->dev_flags)) + remote_dist |= SMP_DIST_ID_KEY; + + if (test_bit(HCI_PRIVACY, &hdev->dev_flags)) + local_dist |= SMP_DIST_ID_KEY; + 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 = 0; - req->resp_key_dist = dist_keys; + req->init_key_dist = local_dist; + req->resp_key_dist = remote_dist; req->auth_req = (authreq & AUTH_REQ_MASK); + + smp->remote_key_dist = remote_dist; 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 = 0; - rsp->resp_key_dist = req->resp_key_dist & dist_keys; + rsp->init_key_dist = req->init_key_dist & remote_dist; + rsp->resp_key_dist = req->resp_key_dist & local_dist; rsp->auth_req = (authreq & AUTH_REQ_MASK); + + smp->remote_key_dist = rsp->init_key_dist; } static u8 check_enc_key_size(struct l2cap_conn *conn, __u8 max_key_size) @@ -356,29 +434,23 @@ static void confirm_work(struct work_struct *work) { struct smp_chan *smp = container_of(work, struct smp_chan, confirm); struct l2cap_conn *conn = smp->conn; - struct crypto_blkcipher *tfm; + struct hci_dev *hdev = conn->hcon->hdev; + struct crypto_blkcipher *tfm = hdev->tfm_aes; struct smp_cmd_pairing_confirm cp; int ret; u8 res[16], reason; BT_DBG("conn %p", conn); - tfm = crypto_alloc_blkcipher("ecb(aes)", 0, CRYPTO_ALG_ASYNC); - if (IS_ERR(tfm)) { - reason = SMP_UNSPECIFIED; - goto error; - } + /* Prevent mutual access to hdev->tfm_aes */ + hci_dev_lock(hdev); - smp->tfm = tfm; + ret = smp_c1(tfm, smp->tk, smp->prnd, smp->preq, smp->prsp, + conn->hcon->init_addr_type, &conn->hcon->init_addr, + conn->hcon->resp_addr_type, &conn->hcon->resp_addr, res); + + hci_dev_unlock(hdev); - if (conn->hcon->out) - ret = smp_c1(tfm, smp->tk, smp->prnd, smp->preq, smp->prsp, - conn->hcon->src_type, &conn->hcon->src, - conn->hcon->dst_type, &conn->hcon->dst, res); - else - ret = smp_c1(tfm, smp->tk, smp->prnd, smp->preq, smp->prsp, - conn->hcon->dst_type, &conn->hcon->dst, - conn->hcon->src_type, &conn->hcon->src, res); if (ret) { reason = SMP_UNSPECIFIED; goto error; @@ -400,7 +472,8 @@ static void random_work(struct work_struct *work) struct smp_chan *smp = container_of(work, struct smp_chan, random); struct l2cap_conn *conn = smp->conn; struct hci_conn *hcon = conn->hcon; - struct crypto_blkcipher *tfm = smp->tfm; + struct hci_dev *hdev = hcon->hdev; + struct crypto_blkcipher *tfm = hdev->tfm_aes; u8 reason, confirm[16], res[16], key[16]; int ret; @@ -411,14 +484,15 @@ static void random_work(struct work_struct *work) BT_DBG("conn %p %s", conn, conn->hcon->out ? "master" : "slave"); - if (hcon->out) - ret = smp_c1(tfm, smp->tk, smp->rrnd, smp->preq, smp->prsp, - hcon->src_type, &hcon->src, - hcon->dst_type, &hcon->dst, res); - else - ret = smp_c1(tfm, smp->tk, smp->rrnd, smp->preq, smp->prsp, - hcon->dst_type, &hcon->dst, - hcon->src_type, &hcon->src, res); + /* Prevent mutual access to hdev->tfm_aes */ + hci_dev_lock(hdev); + + ret = smp_c1(tfm, smp->tk, smp->rrnd, smp->preq, smp->prsp, + hcon->init_addr_type, &hcon->init_addr, + hcon->resp_addr_type, &hcon->resp_addr, res); + + hci_dev_unlock(hdev); + if (ret) { reason = SMP_UNSPECIFIED; goto error; @@ -433,11 +507,9 @@ static void random_work(struct work_struct *work) } if (hcon->out) { - u8 stk[16], rand[8]; - __le16 ediv; - - memset(rand, 0, sizeof(rand)); - ediv = 0; + u8 stk[16]; + __le64 rand = 0; + __le16 ediv = 0; smp_s1(tfm, smp->tk, smp->rrnd, smp->prnd, key); swap128(key, stk); @@ -453,11 +525,9 @@ static void random_work(struct work_struct *work) hci_le_start_enc(hcon, ediv, rand, stk); hcon->enc_key_size = smp->enc_key_size; } else { - u8 stk[16], r[16], rand[8]; - __le16 ediv; - - memset(rand, 0, sizeof(rand)); - ediv = 0; + u8 stk[16], r[16]; + __le64 rand = 0; + __le16 ediv = 0; swap128(smp->prnd, r); smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(r), r); @@ -469,7 +539,7 @@ static void random_work(struct work_struct *work) SMP_MAX_ENC_KEY_SIZE - smp->enc_key_size); hci_add_ltk(hcon->hdev, &hcon->dst, hcon->dst_type, - HCI_SMP_STK_SLAVE, 0, 0, stk, smp->enc_key_size, + HCI_SMP_STK_SLAVE, 0, stk, smp->enc_key_size, ediv, rand); } @@ -479,6 +549,20 @@ error: smp_failure(conn, reason); } +static void smp_reencrypt(struct work_struct *work) +{ + struct smp_chan *smp = container_of(work, struct smp_chan, + reencrypt.work); + struct l2cap_conn *conn = smp->conn; + struct hci_conn *hcon = conn->hcon; + struct smp_ltk *ltk = smp->ltk; + + BT_DBG(""); + + hci_le_start_enc(hcon, ltk->ediv, ltk->rand, ltk->val); + hcon->enc_key_size = ltk->enc_size; +} + static struct smp_chan *smp_chan_create(struct l2cap_conn *conn) { struct smp_chan *smp; @@ -489,6 +573,7 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn) INIT_WORK(&smp->confirm, confirm_work); INIT_WORK(&smp->random, random_work); + INIT_DELAYED_WORK(&smp->reencrypt, smp_reencrypt); smp->conn = conn; conn->smp_chan = smp; @@ -502,11 +587,32 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn) void smp_chan_destroy(struct l2cap_conn *conn) { struct smp_chan *smp = conn->smp_chan; + bool complete; BUG_ON(!smp); - if (smp->tfm) - crypto_free_blkcipher(smp->tfm); + cancel_delayed_work_sync(&smp->reencrypt); + + complete = test_bit(SMP_FLAG_COMPLETE, &smp->smp_flags); + mgmt_smp_complete(conn->hcon, complete); + + /* If pairing failed clean up any keys we might have */ + if (!complete) { + if (smp->ltk) { + list_del(&smp->ltk->list); + kfree(smp->ltk); + } + + if (smp->slave_ltk) { + list_del(&smp->slave_ltk->list); + kfree(smp->slave_ltk); + } + + if (smp->remote_irk) { + list_del(&smp->remote_irk->list); + kfree(smp->remote_irk); + } + } kfree(smp); conn->smp_chan = NULL; @@ -565,6 +671,9 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb) BT_DBG("conn %p", conn); + if (skb->len < sizeof(*req)) + return SMP_UNSPECIFIED; + if (conn->hcon->link_mode & HCI_LM_MASTER) return SMP_CMD_NOTSUPP; @@ -617,6 +726,9 @@ static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb) BT_DBG("conn %p", conn); + if (skb->len < sizeof(*rsp)) + return SMP_UNSPECIFIED; + if (!(conn->hcon->link_mode & HCI_LM_MASTER)) return SMP_CMD_NOTSUPP; @@ -661,6 +773,9 @@ static u8 smp_cmd_pairing_confirm(struct l2cap_conn *conn, struct sk_buff *skb) BT_DBG("conn %p %s", conn, conn->hcon->out ? "master" : "slave"); + if (skb->len < sizeof(smp->pcnf)) + return SMP_UNSPECIFIED; + memcpy(smp->pcnf, skb->data, sizeof(smp->pcnf)); skb_pull(skb, sizeof(smp->pcnf)); @@ -686,6 +801,9 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb) BT_DBG("conn %p", conn); + if (skb->len < sizeof(smp->rrnd)) + return SMP_UNSPECIFIED; + swap128(skb->data, smp->rrnd); skb_pull(skb, sizeof(smp->rrnd)); @@ -699,7 +817,8 @@ static u8 smp_ltk_encrypt(struct l2cap_conn *conn, u8 sec_level) struct smp_ltk *key; struct hci_conn *hcon = conn->hcon; - key = hci_find_ltk_by_addr(hcon->hdev, &hcon->dst, hcon->dst_type); + key = hci_find_ltk_by_addr(hcon->hdev, &hcon->dst, hcon->dst_type, + hcon->out); if (!key) return 0; @@ -724,6 +843,9 @@ static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb) BT_DBG("conn %p", conn); + if (skb->len < sizeof(*rp)) + return SMP_UNSPECIFIED; + if (!(conn->hcon->link_mode & HCI_LM_MASTER)) return SMP_CMD_NOTSUPP; @@ -813,6 +935,15 @@ static int smp_cmd_encrypt_info(struct l2cap_conn *conn, struct sk_buff *skb) struct smp_cmd_encrypt_info *rp = (void *) skb->data; struct smp_chan *smp = conn->smp_chan; + BT_DBG("conn %p", conn); + + if (skb->len < sizeof(*rp)) + return SMP_UNSPECIFIED; + + /* Ignore this PDU if it wasn't requested */ + if (!(smp->remote_key_dist & SMP_DIST_ENC_KEY)) + return 0; + skb_pull(skb, sizeof(*rp)); memcpy(smp->tk, rp->ltk, sizeof(smp->tk)); @@ -826,21 +957,114 @@ static int smp_cmd_master_ident(struct l2cap_conn *conn, struct sk_buff *skb) struct smp_chan *smp = conn->smp_chan; struct hci_dev *hdev = conn->hcon->hdev; struct hci_conn *hcon = conn->hcon; + struct smp_ltk *ltk; u8 authenticated; + BT_DBG("conn %p", conn); + + if (skb->len < sizeof(*rp)) + return SMP_UNSPECIFIED; + + /* Ignore this PDU if it wasn't requested */ + if (!(smp->remote_key_dist & SMP_DIST_ENC_KEY)) + return 0; + + /* Mark the information as received */ + smp->remote_key_dist &= ~SMP_DIST_ENC_KEY; + skb_pull(skb, sizeof(*rp)); hci_dev_lock(hdev); authenticated = (hcon->sec_level == BT_SECURITY_HIGH); - hci_add_ltk(hdev, &hcon->dst, hcon->dst_type, HCI_SMP_LTK, 1, - authenticated, smp->tk, smp->enc_key_size, - rp->ediv, rp->rand); - smp_distribute_keys(conn, 1); + ltk = hci_add_ltk(hdev, &hcon->dst, hcon->dst_type, HCI_SMP_LTK, + authenticated, smp->tk, smp->enc_key_size, + rp->ediv, rp->rand); + smp->ltk = ltk; + if (!(smp->remote_key_dist & SMP_DIST_ID_KEY)) + smp_distribute_keys(conn); hci_dev_unlock(hdev); return 0; } +static int smp_cmd_ident_info(struct l2cap_conn *conn, struct sk_buff *skb) +{ + struct smp_cmd_ident_info *info = (void *) skb->data; + struct smp_chan *smp = conn->smp_chan; + + BT_DBG(""); + + if (skb->len < sizeof(*info)) + return SMP_UNSPECIFIED; + + /* Ignore this PDU if it wasn't requested */ + if (!(smp->remote_key_dist & SMP_DIST_ID_KEY)) + return 0; + + skb_pull(skb, sizeof(*info)); + + memcpy(smp->irk, info->irk, 16); + + return 0; +} + +static int smp_cmd_ident_addr_info(struct l2cap_conn *conn, + struct sk_buff *skb) +{ + struct smp_cmd_ident_addr_info *info = (void *) skb->data; + struct smp_chan *smp = conn->smp_chan; + struct hci_conn *hcon = conn->hcon; + bdaddr_t rpa; + + BT_DBG(""); + + if (skb->len < sizeof(*info)) + return SMP_UNSPECIFIED; + + /* Ignore this PDU if it wasn't requested */ + if (!(smp->remote_key_dist & SMP_DIST_ID_KEY)) + return 0; + + /* Mark the information as received */ + smp->remote_key_dist &= ~SMP_DIST_ID_KEY; + + skb_pull(skb, sizeof(*info)); + + /* Strictly speaking the Core Specification (4.1) allows sending + * an empty address which would force us to rely on just the IRK + * as "identity information". However, since such + * implementations are not known of and in order to not over + * complicate our implementation, simply pretend that we never + * received an IRK for such a device. + */ + if (!bacmp(&info->bdaddr, BDADDR_ANY)) { + BT_ERR("Ignoring IRK with no identity address"); + smp_distribute_keys(conn); + return 0; + } + + bacpy(&smp->id_addr, &info->bdaddr); + smp->id_addr_type = info->addr_type; + + if (hci_bdaddr_is_rpa(&hcon->dst, hcon->dst_type)) + bacpy(&rpa, &hcon->dst); + else + bacpy(&rpa, BDADDR_ANY); + + smp->remote_irk = hci_add_irk(conn->hcon->hdev, &smp->id_addr, + smp->id_addr_type, smp->irk, &rpa); + + /* Track the connection based on the Identity Address from now on */ + bacpy(&hcon->dst, &smp->id_addr); + hcon->dst_type = smp->id_addr_type; + + l2cap_conn_update_id_addr(hcon); + + smp_distribute_keys(conn); + + return 0; +} + int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb) { struct hci_conn *hcon = conn->hcon; @@ -915,7 +1139,13 @@ int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb) break; case SMP_CMD_IDENT_INFO: + reason = smp_cmd_ident_info(conn, skb); + break; + case SMP_CMD_IDENT_ADDR_INFO: + reason = smp_cmd_ident_addr_info(conn, skb); + break; + case SMP_CMD_SIGN_INFO: /* Just ignored */ reason = 0; @@ -937,26 +1167,51 @@ done: return err; } -int smp_distribute_keys(struct l2cap_conn *conn, __u8 force) +static void smp_notify_keys(struct l2cap_conn *conn) +{ + struct smp_chan *smp = conn->smp_chan; + struct hci_conn *hcon = conn->hcon; + struct hci_dev *hdev = hcon->hdev; + + if (smp->remote_irk) + mgmt_new_irk(hdev, smp->remote_irk); + + if (smp->ltk) { + smp->ltk->bdaddr_type = hcon->dst_type; + bacpy(&smp->ltk->bdaddr, &hcon->dst); + mgmt_new_ltk(hdev, smp->ltk); + } + + if (smp->slave_ltk) { + smp->slave_ltk->bdaddr_type = hcon->dst_type; + bacpy(&smp->slave_ltk->bdaddr, &hcon->dst); + mgmt_new_ltk(hdev, smp->slave_ltk); + } +} + +int smp_distribute_keys(struct l2cap_conn *conn) { struct smp_cmd_pairing *req, *rsp; struct smp_chan *smp = conn->smp_chan; + struct hci_conn *hcon = conn->hcon; + struct hci_dev *hdev = hcon->hdev; + bool ltk_encrypt; __u8 *keydist; - BT_DBG("conn %p force %d", conn, force); + BT_DBG("conn %p", conn); - if (!test_bit(HCI_CONN_LE_SMP_PEND, &conn->hcon->flags)) + if (!test_bit(HCI_CONN_LE_SMP_PEND, &hcon->flags)) return 0; rsp = (void *) &smp->prsp[1]; /* The responder sends its keys first */ - if (!force && conn->hcon->out && (rsp->resp_key_dist & 0x07)) + if (hcon->out && (smp->remote_key_dist & 0x07)) return 0; req = (void *) &smp->preq[1]; - if (conn->hcon->out) { + if (hcon->out) { keydist = &rsp->init_key_dist; *keydist &= req->init_key_dist; } else { @@ -964,28 +1219,30 @@ int smp_distribute_keys(struct l2cap_conn *conn, __u8 force) *keydist &= req->resp_key_dist; } - BT_DBG("keydist 0x%x", *keydist); if (*keydist & SMP_DIST_ENC_KEY) { struct smp_cmd_encrypt_info enc; struct smp_cmd_master_ident ident; - struct hci_conn *hcon = conn->hcon; + struct smp_ltk *ltk; u8 authenticated; __le16 ediv; + __le64 rand; get_random_bytes(enc.ltk, sizeof(enc.ltk)); get_random_bytes(&ediv, sizeof(ediv)); - get_random_bytes(ident.rand, sizeof(ident.rand)); + get_random_bytes(&rand, sizeof(rand)); smp_send_cmd(conn, SMP_CMD_ENCRYPT_INFO, sizeof(enc), &enc); authenticated = hcon->sec_level == BT_SECURITY_HIGH; - hci_add_ltk(hcon->hdev, &hcon->dst, hcon->dst_type, - HCI_SMP_LTK_SLAVE, 1, authenticated, - enc.ltk, smp->enc_key_size, ediv, ident.rand); + ltk = hci_add_ltk(hdev, &hcon->dst, hcon->dst_type, + HCI_SMP_LTK_SLAVE, authenticated, enc.ltk, + smp->enc_key_size, ediv, rand); + smp->slave_ltk = ltk; ident.ediv = ediv; + ident.rand = rand; smp_send_cmd(conn, SMP_CMD_MASTER_IDENT, sizeof(ident), &ident); @@ -996,14 +1253,18 @@ int smp_distribute_keys(struct l2cap_conn *conn, __u8 force) struct smp_cmd_ident_addr_info addrinfo; struct smp_cmd_ident_info idinfo; - /* Send a dummy key */ - get_random_bytes(idinfo.irk, sizeof(idinfo.irk)); + memcpy(idinfo.irk, hdev->irk, sizeof(idinfo.irk)); smp_send_cmd(conn, SMP_CMD_IDENT_INFO, sizeof(idinfo), &idinfo); - /* Just public address */ - memset(&addrinfo, 0, sizeof(addrinfo)); - bacpy(&addrinfo.bdaddr, &conn->hcon->src); + /* The hci_conn contains the local identity address + * after the connection has been established. + * + * This is true even when the connection has been + * established using a resolvable random address. + */ + bacpy(&addrinfo.bdaddr, &hcon->src); + addrinfo.addr_type = hcon->src_type; smp_send_cmd(conn, SMP_CMD_IDENT_ADDR_INFO, sizeof(addrinfo), &addrinfo); @@ -1022,9 +1283,34 @@ int smp_distribute_keys(struct l2cap_conn *conn, __u8 force) *keydist &= ~SMP_DIST_SIGN; } - if (conn->hcon->out || force) { - clear_bit(HCI_CONN_LE_SMP_PEND, &conn->hcon->flags); + /* If there are still keys to be received wait for them */ + if ((smp->remote_key_dist & 0x07)) + return 0; + + /* Check if we should try to re-encrypt the link with the LTK. + * SMP_FLAG_LTK_ENCRYPT flag is used to track whether we've + * already tried this (in which case we shouldn't try again). + * + * The request will trigger an encryption key refresh event + * which will cause a call to auth_cfm and eventually lead to + * l2cap_core.c calling this smp_distribute_keys function again + * and thereby completing the process. + */ + if (smp->ltk) + ltk_encrypt = !test_and_set_bit(SMP_FLAG_LTK_ENCRYPT, + &smp->smp_flags); + else + ltk_encrypt = false; + + /* Re-encrypt the link with LTK if possible */ + if (ltk_encrypt && hcon->out) { + queue_delayed_work(hdev->req_workqueue, &smp->reencrypt, + SMP_REENCRYPT_TIMEOUT); + } else { + clear_bit(HCI_CONN_LE_SMP_PEND, &hcon->flags); cancel_delayed_work_sync(&conn->security_timer); + set_bit(SMP_FLAG_COMPLETE, &smp->smp_flags); + smp_notify_keys(conn); smp_chan_destroy(conn); } |