Viewer blindly trusts tensor dimensions and crashes if buffer is too small

[Wumpf]

Tensors/Images take a tensor buffer. Tensor buffers have both a buffer size and a dimension. It's trivial in Rust and C++ to give a dimension that is larger than the actual buffer (it is possible, in Python if you supply tensor dimensions manually, but kinda hard). There's nothing right now that validates this.

The viewer should truncate and warn!

C++ repro case:

   std::string image_path = "rerun-logo.png";
    cv::Mat img = imread(image_path, cv::IMREAD_COLOR);
    if (img.empty()) {
        std::cout << "Could not read the image: " << image_path << std::endl;
        return 1;
    }

    // Log image to Rerun
    cv::cvtColor(img, img, cv::COLOR_BGR2RGB); // Rerun expects RGB format
    // NOTE currently we need to construct a vector to log an image, this will change in the future
    //  see https://github.com/rerun-io/rerun/issues/3794
    std::vector<uint8_t> img_vec(img.total() * img.channels());
    img_vec.assign(img.data, img.data + img.total() * img.channels());
    rec.log(
        "image",
        rerun::Image(
            {static_cast<size_t>(img.rows),
             static_cast<size_t>(img.cols),
             static_cast<size_t>(img.channels() + 1)}, // +1 makes this wrong
            std::move(img_vec)
        )
    );

Curiously enough the crash only happens once we try upload textures to the gpu (would have expected to crash earlier):

[2023-10-19T08:41:32Z ERROR wgpu::backend::direct] Handling wgpu errors as fatal by default
thread 'ThreadId(1)' panicked at 'wgpu error: Validation Error

Caused by:
    In Queue::write_texture
    Copy of 0..1048576 would end up overrunning the bounds of the Source buffer of size 786432

'
wgpu-0.17.0/src/backend/direct.rs:3056
stack backtrace:
   6: core::panicking::panic_fmt
             at core/src/panicking.rs:67:14
   7: core::ops::function::Fn::call

[Wumpf]

There should be several layers of catching this: The viewer warning and working around, the renderer failing gracefully.