Commit 60478054 authored by Johan Hedberg's avatar Johan Hedberg Committed by Marcel Holtmann

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: default avatarJohan Hedberg <>
Signed-off-by: default avatarMarcel Holtmann <>
parent 6bfdfe3c
......@@ -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])
......@@ -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 */
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