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authorJohan Hedberg <johan.hedberg@intel.com>2014-02-18 10:19:31 +0200
committerMarcel Holtmann <marcel@holtmann.org>2014-02-18 00:47:02 -0800
commit60478054a6af7aa8cceb8218d29d27f165f1c9d3 (patch)
treecf713df16202dade0f90d6c00fd6eb8dd2d24592 /net/bluetooth/smp.c
parent6bfdfe3cd68d5a797e0ebfb57068fe7f9c20c93a (diff)
downloadlinux-60478054a6af7aa8cceb8218d29d27f165f1c9d3.tar.bz2
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 <johan.hedberg@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Diffstat (limited to 'net/bluetooth/smp.c')
-rw-r--r--net/bluetooth/smp.c46
1 files changed, 46 insertions, 0 deletions
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])