From 60478054a6af7aa8cceb8218d29d27f165f1c9d3 Mon Sep 17 00:00:00 2001 From: Johan Hedberg Date: Tue, 18 Feb 2014 10:19:31 +0200 Subject: [PATCH] Bluetooth: Add smp_irk_matches helper function This patch adds a helper function to check whether a given IRK matches a given Resolvable Private Address (RPA). The function will be needed for implementing the rest of address resolving support. Signed-off-by: Johan Hedberg Signed-off-by: Marcel Holtmann --- net/bluetooth/smp.c | 46 +++++++++++++++++++++++++++++++++++++++++++++ net/bluetooth/smp.h | 3 +++ 2 files changed, 49 insertions(+) diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c index ae487e17380e..5f500b479f45 100644 --- a/net/bluetooth/smp.c +++ b/net/bluetooth/smp.c @@ -78,6 +78,52 @@ 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); +} + 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]) diff --git a/net/bluetooth/smp.h b/net/bluetooth/smp.h index 777ee93a6c9b..950d039c2ea2 100644 --- a/net/bluetooth/smp.h +++ b/net/bluetooth/smp.h @@ -143,4 +143,7 @@ int smp_user_confirm_reply(struct hci_conn *conn, u16 mgmt_op, __le32 passkey); void smp_chan_destroy(struct l2cap_conn *conn); +bool smp_irk_matches(struct crypto_blkcipher *tfm, u8 irk[16], + bdaddr_t *bdaddr); + #endif /* __SMP_H */ -- 2.30.2