Fixed a regression related to HID report descriptors. (#210)

Author: fdesbiens

common/usbx_host_classes/src/ux_host_class_hid_report_descriptor_get.c

@@ -112,15 +112,15 @@ UINT                    status;
     /* Check for correct transfer and entire descriptor returned.  */
     if ((status == UX_SUCCESS) && (transfer_request -> ux_transfer_request_actual_length == length))
     {
-
+        UINT analysis_failure;
         /* Parse the report descriptor and build the report items.  */
         while (length)
         {
-
+            /* Get one item from the report and analyze it.  */
             /* Make sure this descriptor has at least the minimum length.  */
-            if(length < 3)
+            analysis_failure = _ux_host_class_hid_report_item_analyse(descriptor, &item);
+            if (analysis_failure)
             {
-
               /* Error trap. */
               _ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_DESCRIPTOR_CORRUPTED);
 
@@ -130,10 +130,7 @@ UINT                    status;
               /* Return error status.  */
               status = (UX_DESCRIPTOR_CORRUPTED);
             }
-
-            /* Get one item from the report and analyze it.  */
-            _ux_host_class_hid_report_item_analyse(descriptor, &item);
-
+            
             /* Point the descriptor right after the item identifier.  */
             descriptor +=  item.ux_host_class_hid_item_report_format;
 

common/usbx_host_classes/src/ux_host_class_hid_report_item_analyse.c

@@ -73,7 +73,7 @@ UINT  _ux_host_class_hid_report_item_analyse(UCHAR *descriptor, UX_HOST_CLASS_HI
 {
 
 UCHAR       item_byte;
-    
+UINT        result = UX_SUCCESS;    
 
     /* Get the first byte from the descriptor.  */
     item_byte =  *descriptor;
@@ -89,11 +89,19 @@ UCHAR       item_byte;
         /* Set the type.  */
         item -> ux_host_class_hid_item_report_type =  (item_byte >> 2) & 3;
 
-        /* Get its length (byte 1).  */
-        item -> ux_host_class_hid_item_report_length =  (USHORT) *(descriptor + 1);
+        /* Make sure descriptor has minimal length.*/
+        if (sizeof(descriptor) >= 3)
+        {
+            /* Get its length (byte 1).  */
+            item -> ux_host_class_hid_item_report_length =  (USHORT) *(descriptor + 1);
 
-        /* Then the tag (byte 2).  */
-        item -> ux_host_class_hid_item_report_tag =  *(descriptor + 2);
+            /* Then the tag (byte 2).  */
+            item -> ux_host_class_hid_item_report_tag =  *(descriptor + 2);
+        }
+        else 
+        {
+            result = UX_DESCRIPTOR_CORRUPTED;
+        }
     }
     else
     {
@@ -124,6 +132,6 @@ UCHAR       item_byte;
     }
 
     /* Return successful completion.  */
-    return(UX_SUCCESS);
+    return(result);
 }