ALSA: asihpi: fix an information leak in asihpi_hpi_ioctl()

Add missing limits to keep copied data within allocated buffer.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Eliot Blennerhassett <eliot@blennerhassett.gen.nz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/asihpi/hpi6000.c

@@ -47,7 +47,7 @@
 
 /* operational/messaging errors */
 #define HPI6000_ERROR_MSG_RESP_IDLE_TIMEOUT             901
-
+#define HPI6000_ERROR_RESP_GET_LEN                      902
 #define HPI6000_ERROR_MSG_RESP_GET_RESP_ACK             903
 #define HPI6000_ERROR_MSG_GET_ADR                       904
 #define HPI6000_ERROR_RESP_GET_ADR                      905
@@ -1365,7 +1365,10 @@ static short hpi6000_message_response_sequence(struct hpi_adapter_obj *pao,
 		length = hpi_read_word(pdo, HPI_HIF_ADDR(length));
 	} while (hpi6000_check_PCI2040_error_flag(pao, H6READ) && --timeout);
 	if (!timeout)
-		length = sizeof(struct hpi_response);
+		return HPI6000_ERROR_RESP_GET_LEN;
+
+	if (length > phr->size)
+		return HPI_ERROR_RESPONSE_BUFFER_TOO_SMALL;
 
 	/* get the response */
 	p_data = (u32 *)phr;

sound/pci/asihpi/hpioctl.c

@@ -153,6 +153,8 @@ long asihpi_hpi_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		goto out;
 	}
 
+	res_max_size = min_t(size_t, res_max_size, sizeof(*hr));
+
 	switch (hm->h.function) {
 	case HPI_SUBSYS_CREATE_ADAPTER:
 	case HPI_ADAPTER_DELETE: