usb-mtp: Add some NULL checks for issues pointed out by coverity

CID 1390578: In usb_mtp_write_metadata, parent can never be NULL but
just in case, add an assert
CID 1390592: Check for o->format only if o !=NULL
CID 1390604: Check s->data_out != NULL in usb_mtp_handle_data

Signed-off-by: Bandan Das <bsd@redhat.com>
Message-id: 20180503192028.14353-2-bsd@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
index 6ecf70a..24cff64 100644 (file)
--- a/hw/usb/dev-mtp.c
+++ b/hw/usb/dev-mtp.c
@@ -1446,8 +1446,7 @@ static void usb_mtp_command(MTPState *s, MTPControl *c)
             if (o == NULL) {
                 usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE, c->trans,
                                      0, 0, 0, 0);
-            }
-            if (o->format != FMT_ASSOCIATION) {
+            } else if (o->format != FMT_ASSOCIATION) {
                 usb_mtp_queue_result(s, RES_INVALID_PARENT_OBJECT, c->trans,
                                      0, 0, 0, 0);
             }
@@ -1660,6 +1659,7 @@ static void usb_mtp_write_metadata(MTPState *s)
     uint32_t next_handle = s->next_handle;
 
     assert(!s->write_pending);
+    assert(p != NULL);
 
     utf16_to_str(dataset->length, dataset->filename, filename);
 
@@ -1838,7 +1838,7 @@ static void usb_mtp_handle_data(USBDevice *dev, USBPacket *p)
             p->status = USB_RET_STALL;
             return;
         }
-        if (s->data_out && !s->data_out->first) {
+        if ((s->data_out != NULL) && !s->data_out->first) {
             container_type = TYPE_DATA;
         } else {
             usb_packet_copy(p, &container, sizeof(container));