Commit 191dc7fe authored by Johan Hedberg's avatar Johan Hedberg Committed by Marcel Holtmann
Browse files

Bluetooth: Add support for LE SC numeric comparison 



After the Pairing Confirm and Random PDUs have been exchanged in LE SC
it's time to generate a numeric comparison value using a new smp_g2
cryptographic function (which also builds on AES-CMAC). This patch adds
the smp_g2 implementation and updates the Pairing Random PDU handler to
proceed with the value genration and user confirmation.

Signed-off-by: default avatarJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent dcee2b32

net/bluetooth/smp.c

+70 −1
Original line number Diff line number Diff line
@@ -175,6 +175,32 @@ static int smp_f4(struct crypto_hash *tfm_cmac, const u8 u[32], const u8 v[32], 
	return err;

}



static int smp_g2(struct crypto_hash *tfm_cmac, const u8 u[32], const u8 v[32],

		  const u8 x[16], const u8 y[16], u32 *val)

{

	u8 m[80], tmp[16];

	int err;



	BT_DBG("u %32phN", u);

	BT_DBG("v %32phN", v);

	BT_DBG("x %16phN y %16phN", x, y);



	memcpy(m, y, 16);

	memcpy(m + 16, v, 32);

	memcpy(m + 48, u, 32);



	err = aes_cmac(tfm_cmac, x, m, sizeof(m), tmp);

	if (err)

		return err;



	*val = get_unaligned_le32(tmp);

	*val %= 1000000;



	BT_DBG("val %06u", *val);



	return 0;

}



static int smp_e(struct crypto_blkcipher *tfm, const u8 *k, u8 *r)

{

	struct blkcipher_desc desc;
@@ -1270,6 +1296,10 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb) 
{

	struct l2cap_chan *chan = conn->smp;

	struct smp_chan *smp = chan->data;

	struct hci_conn *hcon = conn->hcon;

	u8 *pkax, *pkbx, *na, *nb;

	u32 passkey;

	int err;



	BT_DBG("conn %p", conn);
@@ -1279,7 +1309,46 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb) 
	memcpy(smp->rrnd, skb->data, sizeof(smp->rrnd));

	skb_pull(skb, sizeof(smp->rrnd));



	if (!test_bit(SMP_FLAG_SC, &smp->flags))

		return smp_random(smp);



	if (hcon->out) {

		u8 cfm[16];



		err = smp_f4(smp->tfm_cmac, smp->remote_pk, smp->local_pk,

			     smp->rrnd, 0, cfm);

		if (err)

			return SMP_UNSPECIFIED;



		if (memcmp(smp->pcnf, cfm, 16))

			return SMP_CONFIRM_FAILED;



		pkax = smp->local_pk;

		pkbx = smp->remote_pk;

		na   = smp->prnd;

		nb   = smp->rrnd;

	} else {

		smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(smp->prnd),

			     smp->prnd);

		SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK);



		pkax = smp->remote_pk;

		pkbx = smp->local_pk;

		na   = smp->rrnd;

		nb   = smp->prnd;

	}



	err = smp_g2(smp->tfm_cmac, pkax, pkbx, na, nb, &passkey);

	if (err)

		return SMP_UNSPECIFIED;



	err = mgmt_user_confirm_request(hcon->hdev, &hcon->dst,

					hcon->type, hcon->dst_type,

					passkey, 0);

	if (err)

		return SMP_UNSPECIFIED;



	return 0;

}



static bool smp_ltk_encrypt(struct l2cap_conn *conn, u8 sec_level)

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