From: Johan Hedberg <johan.hedberg@xxxxxxxxx>
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 <johan.hedberg@xxxxxxxxx>
---
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 */
--
1.8.5.3
--
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