nfc: st21nfca: fix memory leaks in EVT_TRANSACTION handling

Error paths do not free previously allocated memory. Add devm_kfree() to
those failure paths.

Fixes: 26fc6c7f ("NFC: st21nfca: Add HCI transaction event support")
Fixes: 4fbcc1a4 ("nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Faltesek <mfaltesek@google.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/nfc/st21nfca/se.c

@@ -326,22 +326,29 @@ int st21nfca_connectivity_event_received(struct nfc_hci_dev *hdev, u8 host,
 		transaction->aid_len = skb->data[1];
 
 		/* Checking if the length of the AID is valid */
-		if (transaction->aid_len > sizeof(transaction->aid))
+		if (transaction->aid_len > sizeof(transaction->aid)) {
+			devm_kfree(dev, transaction);
 			return -EINVAL;
+		}
 
 		memcpy(transaction->aid, &skb->data[2],
 		       transaction->aid_len);
 
 		/* Check next byte is PARAMETERS tag (82) */
 		if (skb->data[transaction->aid_len + 2] !=
-		    NFC_EVT_TRANSACTION_PARAMS_TAG)
+		    NFC_EVT_TRANSACTION_PARAMS_TAG) {
+			devm_kfree(dev, transaction);
 			return -EPROTO;
+		}
 
 		transaction->params_len = skb->data[transaction->aid_len + 3];
 
 		/* Total size is allocated (skb->len - 2) minus fixed array members */
-		if (transaction->params_len > ((skb->len - 2) - sizeof(struct nfc_evt_transaction)))
+		if (transaction->params_len > ((skb->len - 2) -
+		    sizeof(struct nfc_evt_transaction))) {
+			devm_kfree(dev, transaction);
 			return -EINVAL;
+		}
 
 		memcpy(transaction->params, skb->data +
 		       transaction->aid_len + 4, transaction->params_len);