From 191dc7fe2d3a8dde70b37a1fd086a32c1f4e1dcf Mon Sep 17 00:00:00 2001 From: Johan Hedberg Date: Fri, 6 Jun 2014 11:39:49 +0300 Subject: [PATCH] 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: Johan Hedberg Signed-off-by: Marcel Holtmann --- net/bluetooth/smp.c | 71 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 70 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c index 6207f32d1c6b..103f05aff7e9 100644 --- a/net/bluetooth/smp.c +++ b/net/bluetooth/smp.c @@ -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)); - return smp_random(smp); + 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) -- 2.20.1