Bluetooth: Use kzfree instead of kfree in security manager

Within the security manager, it makes sense to use kzfree instead of
kfree for all data structures. This ensures that no key material leaks
by accident.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

net/bluetooth/smp.c

@@ -681,9 +681,9 @@ static void smp_chan_destroy(struct l2cap_conn *conn)
 	complete = test_bit(SMP_FLAG_COMPLETE, &smp->flags);
 	mgmt_smp_complete(hcon, complete);
 
-	kfree(smp->csrk);
-	kfree(smp->slave_csrk);
-	kfree(smp->link_key);
+	kzfree(smp->csrk);
+	kzfree(smp->slave_csrk);
+	kzfree(smp->link_key);
 
 	crypto_free_blkcipher(smp->tfm_aes);
 	crypto_free_hash(smp->tfm_cmac);
@@ -717,7 +717,7 @@ static void smp_chan_destroy(struct l2cap_conn *conn)
 	}
 
 	chan->data = NULL;
-	kfree(smp);
+	kzfree(smp);
 	hci_conn_drop(hcon);
 }
 
@@ -1097,13 +1097,13 @@ static void sc_generate_link_key(struct smp_chan *smp)
 		return;
 
 	if (smp_h6(smp->tfm_cmac, smp->tk, tmp1, smp->link_key)) {
-		kfree(smp->link_key);
+		kzfree(smp->link_key);
 		smp->link_key = NULL;
 		return;
 	}
 
 	if (smp_h6(smp->tfm_cmac, smp->link_key, lebr, smp->link_key)) {
-		kfree(smp->link_key);
+		kzfree(smp->link_key);
 		smp->link_key = NULL;
 		return;
 	}
@@ -1300,7 +1300,7 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
 	smp->tfm_aes = crypto_alloc_blkcipher("ecb(aes)", 0, CRYPTO_ALG_ASYNC);
 	if (IS_ERR(smp->tfm_aes)) {
 		BT_ERR("Unable to create ECB crypto context");
-		kfree(smp);
+		kzfree(smp);
 		return NULL;
 	}
 
@@ -1308,7 +1308,7 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
 	if (IS_ERR(smp->tfm_cmac)) {
 		BT_ERR("Unable to create CMAC crypto context");
 		crypto_free_blkcipher(smp->tfm_aes);
-		kfree(smp);
+		kzfree(smp);
 		return NULL;
 	}