diff options
Diffstat (limited to 'net/bluetooth/smp.c')
| -rw-r--r-- | net/bluetooth/smp.c | 702 | 
1 files changed, 702 insertions, 0 deletions
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c new file mode 100644 index 000000000000..391888b88a92 --- /dev/null +++ b/net/bluetooth/smp.c @@ -0,0 +1,702 @@ +/* +   BlueZ - Bluetooth protocol stack for Linux +   Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). + +   This program is free software; you can redistribute it and/or modify +   it under the terms of the GNU General Public License version 2 as +   published by the Free Software Foundation; + +   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS +   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. +   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY +   CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES +   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + +   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS, +   COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS +   SOFTWARE IS DISCLAIMED. +*/ + +#include <net/bluetooth/bluetooth.h> +#include <net/bluetooth/hci_core.h> +#include <net/bluetooth/l2cap.h> +#include <net/bluetooth/smp.h> +#include <linux/crypto.h> +#include <linux/scatterlist.h> +#include <crypto/b128ops.h> + +#define SMP_TIMEOUT 30000 /* 30 seconds */ + +static inline void swap128(u8 src[16], u8 dst[16]) +{ +	int i; +	for (i = 0; i < 16; i++) +		dst[15 - i] = src[i]; +} + +static inline void swap56(u8 src[7], u8 dst[7]) +{ +	int i; +	for (i = 0; i < 7; i++) +		dst[6 - i] = src[i]; +} + +static int smp_e(struct crypto_blkcipher *tfm, const u8 *k, u8 *r) +{ +	struct blkcipher_desc desc; +	struct scatterlist sg; +	int err, iv_len; +	unsigned char iv[128]; + +	if (tfm == NULL) { +		BT_ERR("tfm %p", tfm); +		return -EINVAL; +	} + +	desc.tfm = tfm; +	desc.flags = 0; + +	err = crypto_blkcipher_setkey(tfm, k, 16); +	if (err) { +		BT_ERR("cipher setkey failed: %d", err); +		return err; +	} + +	sg_init_one(&sg, r, 16); + +	iv_len = crypto_blkcipher_ivsize(tfm); +	if (iv_len) { +		memset(&iv, 0xff, iv_len); +		crypto_blkcipher_set_iv(tfm, iv, iv_len); +	} + +	err = crypto_blkcipher_encrypt(&desc, &sg, &sg, 16); +	if (err) +		BT_ERR("Encrypt data error %d", err); + +	return err; +} + +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]) +{ +	u8 p1[16], p2[16]; +	int err; + +	memset(p1, 0, 16); + +	/* p1 = pres || preq || _rat || _iat */ +	swap56(pres, p1); +	swap56(preq, p1 + 7); +	p1[14] = _rat; +	p1[15] = _iat; + +	memset(p2, 0, 16); + +	/* p2 = padding || ia || ra */ +	baswap((bdaddr_t *) (p2 + 4), ia); +	baswap((bdaddr_t *) (p2 + 10), ra); + +	/* res = r XOR p1 */ +	u128_xor((u128 *) res, (u128 *) r, (u128 *) p1); + +	/* res = e(k, res) */ +	err = smp_e(tfm, k, res); +	if (err) { +		BT_ERR("Encrypt data error"); +		return err; +	} + +	/* res = res XOR p2 */ +	u128_xor((u128 *) res, (u128 *) res, (u128 *) p2); + +	/* res = e(k, res) */ +	err = smp_e(tfm, k, res); +	if (err) +		BT_ERR("Encrypt data error"); + +	return err; +} + +static int smp_s1(struct crypto_blkcipher *tfm, u8 k[16], +			u8 r1[16], u8 r2[16], u8 _r[16]) +{ +	int err; + +	/* Just least significant octets from r1 and r2 are considered */ +	memcpy(_r, r1 + 8, 8); +	memcpy(_r + 8, r2 + 8, 8); + +	err = smp_e(tfm, k, _r); +	if (err) +		BT_ERR("Encrypt data error"); + +	return err; +} + +static int smp_rand(u8 *buf) +{ +	get_random_bytes(buf, 16); + +	return 0; +} + +static struct sk_buff *smp_build_cmd(struct l2cap_conn *conn, u8 code, +						u16 dlen, void *data) +{ +	struct sk_buff *skb; +	struct l2cap_hdr *lh; +	int len; + +	len = L2CAP_HDR_SIZE + sizeof(code) + dlen; + +	if (len > conn->mtu) +		return NULL; + +	skb = bt_skb_alloc(len, GFP_ATOMIC); +	if (!skb) +		return NULL; + +	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE); +	lh->len = cpu_to_le16(sizeof(code) + dlen); +	lh->cid = cpu_to_le16(L2CAP_CID_SMP); + +	memcpy(skb_put(skb, sizeof(code)), &code, sizeof(code)); + +	memcpy(skb_put(skb, dlen), data, dlen); + +	return skb; +} + +static void smp_send_cmd(struct l2cap_conn *conn, u8 code, u16 len, void *data) +{ +	struct sk_buff *skb = smp_build_cmd(conn, code, len, data); + +	BT_DBG("code 0x%2.2x", code); + +	if (!skb) +		return; + +	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 *req, +				struct smp_cmd_pairing *rsp, +				__u8 authreq) +{ +	u8 dist_keys; + +	dist_keys = 0; +	if (test_bit(HCI_PAIRABLE, &conn->hcon->hdev->flags)) { +		dist_keys = SMP_DIST_ENC_KEY | SMP_DIST_ID_KEY | SMP_DIST_SIGN; +		authreq |= SMP_AUTH_BONDING; +	} + +	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 = dist_keys; +		req->resp_key_dist = dist_keys; +		req->auth_req = authreq; +		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 = req->init_key_dist & dist_keys; +	rsp->resp_key_dist = req->resp_key_dist & dist_keys; +	rsp->auth_req = authreq; +} + +static u8 check_enc_key_size(struct l2cap_conn *conn, __u8 max_key_size) +{ +	if ((max_key_size > SMP_MAX_ENC_KEY_SIZE) || +			(max_key_size < SMP_MIN_ENC_KEY_SIZE)) +		return SMP_ENC_KEY_SIZE; + +	conn->smp_key_size = max_key_size; + +	return 0; +} + +static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb) +{ +	struct smp_cmd_pairing rsp, *req = (void *) skb->data; +	u8 key_size; + +	BT_DBG("conn %p", conn); + +	conn->preq[0] = SMP_CMD_PAIRING_REQ; +	memcpy(&conn->preq[1], req, sizeof(*req)); +	skb_pull(skb, sizeof(*req)); + +	if (req->oob_flag) +		return SMP_OOB_NOT_AVAIL; + +	/* We didn't start the pairing, so no requirements */ +	build_pairing_cmd(conn, req, &rsp, SMP_AUTH_NONE); + +	key_size = min(req->max_key_size, rsp.max_key_size); +	if (check_enc_key_size(conn, key_size)) +		return SMP_ENC_KEY_SIZE; + +	/* Just works */ +	memset(conn->tk, 0, sizeof(conn->tk)); + +	conn->prsp[0] = SMP_CMD_PAIRING_RSP; +	memcpy(&conn->prsp[1], &rsp, sizeof(rsp)); + +	smp_send_cmd(conn, SMP_CMD_PAIRING_RSP, sizeof(rsp), &rsp); + +	mod_timer(&conn->security_timer, jiffies + +					msecs_to_jiffies(SMP_TIMEOUT)); + +	return 0; +} + +static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb) +{ +	struct smp_cmd_pairing *req, *rsp = (void *) skb->data; +	struct smp_cmd_pairing_confirm cp; +	struct crypto_blkcipher *tfm = conn->hcon->hdev->tfm; +	int ret; +	u8 res[16], key_size; + +	BT_DBG("conn %p", conn); + +	skb_pull(skb, sizeof(*rsp)); + +	req = (void *) &conn->preq[1]; + +	key_size = min(req->max_key_size, rsp->max_key_size); +	if (check_enc_key_size(conn, key_size)) +		return SMP_ENC_KEY_SIZE; + +	if (rsp->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], rsp, sizeof(*rsp)); + +	ret = smp_rand(conn->prnd); +	if (ret) +		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 SMP_UNSPECIFIED; + +	swap128(res, cp.confirm_val); + +	smp_send_cmd(conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cp), &cp); + +	return 0; +} + +static u8 smp_cmd_pairing_confirm(struct l2cap_conn *conn, struct sk_buff *skb) +{ +	struct crypto_blkcipher *tfm = conn->hcon->hdev->tfm; + +	BT_DBG("conn %p %s", conn, conn->hcon->out ? "master" : "slave"); + +	memcpy(conn->pcnf, skb->data, sizeof(conn->pcnf)); +	skb_pull(skb, sizeof(conn->pcnf)); + +	if (conn->hcon->out) { +		u8 random[16]; + +		swap128(conn->prnd, random); +		smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(random), +								random); +	} else { +		struct smp_cmd_pairing_confirm cp; +		int ret; +		u8 res[16]; + +		ret = smp_rand(conn->prnd); +		if (ret) +			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 SMP_CONFIRM_FAILED; + +		swap128(res, cp.confirm_val); + +		smp_send_cmd(conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cp), &cp); +	} + +	mod_timer(&conn->security_timer, jiffies + +					msecs_to_jiffies(SMP_TIMEOUT)); + +	return 0; +} + +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; +	int ret; +	u8 key[16], res[16], random[16], confirm[16]; + +	swap128(skb->data, random); +	skb_pull(skb, sizeof(random)); + +	if (conn->hcon->out) +		ret = smp_c1(tfm, conn->tk, random, conn->preq, conn->prsp, 0, +				conn->src, conn->hcon->dst_type, conn->dst, +				res); +	else +		ret = smp_c1(tfm, conn->tk, random, conn->preq, conn->prsp, +				conn->hcon->dst_type, conn->dst, 0, conn->src, +				res); +	if (ret) +		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) { +		BT_ERR("Pairing failed (confirmation values mismatch)"); +		return SMP_CONFIRM_FAILED; +	} + +	if (conn->hcon->out) { +		u8 stk[16], rand[8]; +		__le16 ediv; + +		memset(rand, 0, sizeof(rand)); +		ediv = 0; + +		smp_s1(tfm, conn->tk, random, conn->prnd, key); +		swap128(key, stk); + +		memset(stk + conn->smp_key_size, 0, +				SMP_MAX_ENC_KEY_SIZE - conn->smp_key_size); + +		hci_le_start_enc(hcon, ediv, rand, stk); +		hcon->enc_key_size = conn->smp_key_size; +	} else { +		u8 stk[16], r[16], rand[8]; +		__le16 ediv; + +		memset(rand, 0, sizeof(rand)); +		ediv = 0; + +		swap128(conn->prnd, r); +		smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(r), r); + +		smp_s1(tfm, conn->tk, conn->prnd, random, key); +		swap128(key, stk); + +		memset(stk + conn->smp_key_size, 0, +				SMP_MAX_ENC_KEY_SIZE - conn->smp_key_size); + +		hci_add_ltk(conn->hcon->hdev, 0, conn->dst, conn->smp_key_size, +							ediv, rand, stk); +	} + +	return 0; +} + +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; +	struct hci_conn *hcon = conn->hcon; + +	BT_DBG("conn %p", conn); + +	if (test_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend)) +		return 0; + +	skb_pull(skb, sizeof(*rp)); + +	memset(&cp, 0, sizeof(cp)); +	build_pairing_cmd(conn, &cp, NULL, rp->auth_req); + +	conn->preq[0] = SMP_CMD_PAIRING_REQ; +	memcpy(&conn->preq[1], &cp, sizeof(cp)); + +	smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp); + +	mod_timer(&conn->security_timer, jiffies + +					msecs_to_jiffies(SMP_TIMEOUT)); + +	set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend); + +	return 0; +} + +int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level) +{ +	struct hci_conn *hcon = conn->hcon; +	__u8 authreq; + +	BT_DBG("conn %p hcon %p level 0x%2.2x", conn, hcon, sec_level); + +	if (!lmp_host_le_capable(hcon->hdev)) +		return 1; + +	if (IS_ERR(hcon->hdev->tfm)) +		return 1; + +	if (test_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend)) +		return 0; + +	if (sec_level == BT_SECURITY_LOW) +		return 1; + +	if (hcon->sec_level >= sec_level) +		return 1; + +	authreq = seclevel_to_authreq(sec_level); + +	if (hcon->link_mode & HCI_LM_MASTER) { +		struct smp_cmd_pairing cp; +		struct link_key *key; + +		key = hci_find_link_key_type(hcon->hdev, conn->dst, +							HCI_LK_SMP_LTK); +		if (key) { +			struct key_master_id *master = (void *) key->data; + +			hci_le_start_enc(hcon, master->ediv, master->rand, +								key->val); +			hcon->enc_key_size = key->pin_len; + +			goto done; +		} + +		build_pairing_cmd(conn, &cp, NULL, authreq); +		conn->preq[0] = SMP_CMD_PAIRING_REQ; +		memcpy(&conn->preq[1], &cp, sizeof(cp)); + +		mod_timer(&conn->security_timer, jiffies + +					msecs_to_jiffies(SMP_TIMEOUT)); + +		smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp); +	} else { +		struct smp_cmd_security_req cp; +		cp.auth_req = authreq; +		smp_send_cmd(conn, SMP_CMD_SECURITY_REQ, sizeof(cp), &cp); +	} + +done: +	hcon->pending_sec_level = sec_level; +	set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend); + +	return 0; +} + +static int smp_cmd_encrypt_info(struct l2cap_conn *conn, struct sk_buff *skb) +{ +	struct smp_cmd_encrypt_info *rp = (void *) skb->data; + +	skb_pull(skb, sizeof(*rp)); + +	memcpy(conn->tk, rp->ltk, sizeof(conn->tk)); + +	return 0; +} + +static int smp_cmd_master_ident(struct l2cap_conn *conn, struct sk_buff *skb) +{ +	struct smp_cmd_master_ident *rp = (void *) skb->data; + +	skb_pull(skb, sizeof(*rp)); + +	hci_add_ltk(conn->hcon->hdev, 1, conn->src, conn->smp_key_size, +						rp->ediv, rp->rand, conn->tk); + +	smp_distribute_keys(conn, 1); + +	return 0; +} + +int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb) +{ +	__u8 code = skb->data[0]; +	__u8 reason; +	int err = 0; + +	if (!lmp_host_le_capable(conn->hcon->hdev)) { +		err = -ENOTSUPP; +		reason = SMP_PAIRING_NOTSUPP; +		goto done; +	} + +	if (IS_ERR(conn->hcon->hdev->tfm)) { +		err = PTR_ERR(conn->hcon->hdev->tfm); +		reason = SMP_PAIRING_NOTSUPP; +		goto done; +	} + +	skb_pull(skb, sizeof(code)); + +	switch (code) { +	case SMP_CMD_PAIRING_REQ: +		reason = smp_cmd_pairing_req(conn, skb); +		break; + +	case SMP_CMD_PAIRING_FAIL: +		reason = 0; +		err = -EPERM; +		break; + +	case SMP_CMD_PAIRING_RSP: +		reason = smp_cmd_pairing_rsp(conn, skb); +		break; + +	case SMP_CMD_SECURITY_REQ: +		reason = smp_cmd_security_req(conn, skb); +		break; + +	case SMP_CMD_PAIRING_CONFIRM: +		reason = smp_cmd_pairing_confirm(conn, skb); +		break; + +	case SMP_CMD_PAIRING_RANDOM: +		reason = smp_cmd_pairing_random(conn, skb); +		break; + +	case SMP_CMD_ENCRYPT_INFO: +		reason = smp_cmd_encrypt_info(conn, skb); +		break; + +	case SMP_CMD_MASTER_IDENT: +		reason = smp_cmd_master_ident(conn, skb); +		break; + +	case SMP_CMD_IDENT_INFO: +	case SMP_CMD_IDENT_ADDR_INFO: +	case SMP_CMD_SIGN_INFO: +		/* Just ignored */ +		reason = 0; +		break; + +	default: +		BT_DBG("Unknown command code 0x%2.2x", code); + +		reason = SMP_CMD_NOTSUPP; +		err = -EOPNOTSUPP; +		goto done; +	} + +done: +	if (reason) +		smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason), +								&reason); + +	kfree_skb(skb); +	return err; +} + +int smp_distribute_keys(struct l2cap_conn *conn, __u8 force) +{ +	struct smp_cmd_pairing *req, *rsp; +	__u8 *keydist; + +	BT_DBG("conn %p force %d", conn, force); + +	if (IS_ERR(conn->hcon->hdev->tfm)) +		return PTR_ERR(conn->hcon->hdev->tfm); + +	rsp = (void *) &conn->prsp[1]; + +	/* The responder sends its keys first */ +	if (!force && conn->hcon->out && (rsp->resp_key_dist & 0x07)) +		return 0; + +	req = (void *) &conn->preq[1]; + +	if (conn->hcon->out) { +		keydist = &rsp->init_key_dist; +		*keydist &= req->init_key_dist; +	} else { +		keydist = &rsp->resp_key_dist; +		*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; +		__le16 ediv; + +		get_random_bytes(enc.ltk, sizeof(enc.ltk)); +		get_random_bytes(&ediv, sizeof(ediv)); +		get_random_bytes(ident.rand, sizeof(ident.rand)); + +		smp_send_cmd(conn, SMP_CMD_ENCRYPT_INFO, sizeof(enc), &enc); + +		hci_add_ltk(conn->hcon->hdev, 1, conn->dst, conn->smp_key_size, +						ediv, ident.rand, enc.ltk); + +		ident.ediv = cpu_to_le16(ediv); + +		smp_send_cmd(conn, SMP_CMD_MASTER_IDENT, sizeof(ident), &ident); + +		*keydist &= ~SMP_DIST_ENC_KEY; +	} + +	if (*keydist & SMP_DIST_ID_KEY) { +		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)); + +		smp_send_cmd(conn, SMP_CMD_IDENT_INFO, sizeof(idinfo), &idinfo); + +		/* Just public address */ +		memset(&addrinfo, 0, sizeof(addrinfo)); +		bacpy(&addrinfo.bdaddr, conn->src); + +		smp_send_cmd(conn, SMP_CMD_IDENT_ADDR_INFO, sizeof(addrinfo), +								&addrinfo); + +		*keydist &= ~SMP_DIST_ID_KEY; +	} + +	if (*keydist & SMP_DIST_SIGN) { +		struct smp_cmd_sign_info sign; + +		/* Send a dummy key */ +		get_random_bytes(sign.csrk, sizeof(sign.csrk)); + +		smp_send_cmd(conn, SMP_CMD_SIGN_INFO, sizeof(sign), &sign); + +		*keydist &= ~SMP_DIST_SIGN; +	} + +	return 0; +}  |