WebGL: validations and fixes to avoid buffer/texture overflow

Source/modules/webgl/WebGLRenderingContextBase.cpp

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1607 matching lines @@
 
 void WebGLRenderingContextBase::bufferSubDataImpl(GLenum target, long long offset, GLsizeiptr size, const void* data)
 {
     WebGLBuffer* buffer = validateBufferDataTarget("bufferSubData", target);
     if (!buffer)
         return;
     if (!validateValueFitNonNegInt32("bufferSubData", "offset", offset))
         return;
     if (!data)
         return;
+    if (offset + static_cast<long long>(size) > buffer->getSize()) {
+        synthesizeGLError(GL_INVALID_VALUE, "bufferSubData", "buffer overflow");
+        return;
+    }
 
     webContext()->bufferSubData(target, static_cast<GLintptr>(offset), size, data);
 }
 
 void WebGLRenderingContextBase::bufferSubData(GLenum target, long long offset, DOMArrayBuffer* data)
 {
     if (isContextLost())
         return;
     if (!data)
         return;
@@ skipping 4252 matching lines @@
     case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT: {
         const int kBlockWidth = 4;
         const int kBlockHeight = 4;
         if ((xoffset % kBlockWidth) || (yoffset % kBlockHeight)) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "xoffset or yoffset not multiple of 4");
             return false;
         }
-        if (width - xoffset > tex->getWidth(target, level)
-            || height - yoffset > tex->getHeight(target, level)) {
-            synthesizeGLError(GL_INVALID_OPERATION, functionName, "dimensions out of range");
+        // Before checking if it is in the range, check if overflow happens first.
+        Checked<GLint, RecordOverflow> maxX = xoffset, maxY = yoffset;
+        maxX += width;
+        maxY += height;
+        if (maxX.hasOverflowed() || maxY.hasOverflowed() || maxX.unsafeGet() > tex->getWidth(target, level)
+            || maxY.unsafeGet() > tex->getHeight(target, level)) {
+            synthesizeGLError(GL_INVALID_VALUE, functionName, "dimensions out of range");
             return false;
         }
         return validateCompressedTexDimensions(functionName, TexSubImage2D, target, level, width, height, format);
     }
     case GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG:
     case GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG:
     case GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG:
     case GL_COMPRESSED_RGBA_PVRTC_2BPPV1_IMG: {
         if ((xoffset != 0) || (yoffset != 0)) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "xoffset and yoffset must be zero");
@@ skipping 808 matching lines @@
 
     return totalBytesPerPixel;
 }
 
 DrawingBuffer* WebGLRenderingContextBase::drawingBuffer() const
 {
     return m_drawingBuffer.get();
 }
 
 } // namespace blink