X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=MdePkg%2FLibrary%2FUefiDevicePathLib%2FDevicePathUtilities.c;h=bb4a56398e3c92c6b249d765d90b3144f72f492c;hb=41bfaffd13094d9042110091e6c37adf20c4032c;hp=82419a4e1b2ae618aa061b5462e08a8e0b6d2030;hpb=e9fb71b29965aff2bf9e9caa1837ddcd069f2a27;p=mirror_edk2.git

diff --git a/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c b/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
index 82419a4e1b..bb4a56398e 100644
--- a/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
+++ b/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
@@ -61,16 +61,18 @@ IsDevicePathValid (
 
   ASSERT (DevicePath != NULL);
 
-  if (MaxSize == 0){
+  if (MaxSize == 0) {
     MaxSize = MAX_UINTN;
   }
 
-  Size = 0;
-  Count = 0;
+  //
+  // Validate the input size big enough to touch the first node.
+  //
+  if (MaxSize < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
+    return FALSE;
+  }
 
-  while (MaxSize >= sizeof (EFI_DEVICE_PATH_PROTOCOL) &&
-        (MaxSize - sizeof (EFI_DEVICE_PATH_PROTOCOL) >= Size) &&
-        !IsDevicePathEnd (DevicePath)) {
+  for (Count = 0, Size = 0; !IsDevicePathEnd (DevicePath); DevicePath = NextDevicePathNode (DevicePath)) {
     NodeLength = DevicePathNodeLength (DevicePath);
     if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
       return FALSE;
@@ -79,17 +81,21 @@ IsDevicePathValid (
     if (NodeLength > MAX_UINTN - Size) {
       return FALSE;
     }
-
     Size += NodeLength;
 
+    //
+    // Validate next node before touch it.
+    //
+    if (Size > MaxSize - END_DEVICE_PATH_LENGTH ) {
+      return FALSE;
+    }
+
     if (PcdGet32 (PcdMaximumDevicePathNodeCount) > 0) {
       Count++;
       if (Count >= PcdGet32 (PcdMaximumDevicePathNodeCount)) {
         return FALSE;
       }
     }
-
-    DevicePath = NextDevicePathNode (DevicePath);
   }
 
   //