Validate level exists for TexSubImage calls.

src/libANGLE/validationES2.cpp

@@ -368,10 +368,16 @@ bool ValidateES2TexImageParameters(Context *context,
 
     if (isSubImage)
     {
+        GLenum textureFormat = texture->getFormat(target, level).asSized();
+        if (textureFormat == GL_NONE)
+        {
+            context->handleError(Error(GL_INVALID_OPERATION, "Texture level does not exist."));
+            return false;
+        }
+
         if (format != GL_NONE)
         {
-            if (gl::GetSizedInternalFormat(format, type) !=
-                texture->getFormat(target, level).asSized())
+            if (gl::GetSizedInternalFormat(format, type) != textureFormat)
             {
                 context->handleError(Error(GL_INVALID_OPERATION));
                 return false;

src/libANGLE/validationES3.cpp

@@ -168,6 +168,12 @@ bool ValidateES3TexImageParametersBase(Context *context,
     // Validate texture formats
     GLenum actualInternalFormat =
         isSubImage ? texture->getFormat(target, level).asSized() : internalformat;
+    if (isSubImage && actualInternalFormat == GL_NONE)
+    {
+        context->handleError(Error(GL_INVALID_OPERATION, "Texture level does not exist."));
+        return false;
+    }
+
     const gl::InternalFormat &actualFormatInfo = gl::GetInternalFormatInfo(actualInternalFormat);
     if (isCompressed)
     {

src/tests/gl_tests/TextureTest.cpp

@@ -1194,6 +1194,16 @@ TEST_P(Texture2DTest, NegativeAPISubImage)
     const GLubyte *pixels[20] = { 0 };
     glTexSubImage2D(GL_TEXTURE_2D, 0, 1, 1, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
     EXPECT_GL_ERROR(GL_INVALID_VALUE);
+
+    if (extensionEnabled("GL_EXT_texture_storage"))
+    {
+        // Create a 1-level immutable texture.
+        glTexStorage2DEXT(GL_TEXTURE_2D, 1, GL_RGBA8, 2, 2);
+
+        // Try calling sub image on the second level.
+        glTexSubImage2D(GL_TEXTURE_2D, 1, 1, 1, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+        EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    }
 }
 
 // Test that querying GL_TEXTURE_BINDING* doesn't cause an unexpected error.