Commit message: Fix one division by zero

PiperOrigin-RevId: 369474832
Change-Id: I1082858ed78d9b2e4738ce30b231955973d49e1e
CVE: CVE-2021-29528
CWE: CWE-369
Vulnerability description: TensorFlow is an end-to-end open source platform for machine learning. An attacker can trigger a division by 0 in `tf.raw_ops.QuantizedMul`. This is because the implementation(https://github.com/tensorflow/tensorflow/blob/55900e961ed4a23b438392024912154a2c2f5e85/tensorflow/core/kernels/quantized_mul_op.cc#L188-L198) does a division by a quantity that is controlled by the caller. The fix will be included in TensorFlow 2.5.0. We will also cherrypick this commit on TensorFlow 2.4.2, TensorFlow 2.3.3, TensorFlow 2.2.3 and TensorFlow 2.1.4, as these are also affected and still in supported range.

Project: tensorflow
File: quantized_mul_op.cc

  void Compute(OpKernelContext* context) override {
    const Tensor& x = context->input(0);
    const Tensor& y = context->input(1);
    const float min_x = context->input(2).flat<float>()(0);
    const float max_x = context->input(3).flat<float>()(0);
    const float min_y = context->input(4).flat<float>()(0);
    const float max_y = context->input(5).flat<float>()(0);

    BCast bcast(BCast::FromShape(x.shape()), BCast::FromShape(y.shape()));
    if (!bcast.IsValid()) {
      context->SetStatus(errors::InvalidArgument(
          "Incompatible shapes: ", x.shape().DebugString(), " vs. ",
          y.shape().DebugString()));
      return;
    }
    Tensor* z;
    OP_REQUIRES_OK(context, context->allocate_output(
                                0, BCast::ToShape(bcast.output_shape()), &z));

    // Make sure that we have valid quantization ranges for the input buffers.
    // If the difference between the min and max is negative or zero, it makes
    // it hard to do meaningful intermediate operations on the values.
    OP_REQUIRES(context, (max_x > min_x),
                errors::InvalidArgument("max_x must be larger than min_a."));
    OP_REQUIRES(context, (max_y > min_y),
                errors::InvalidArgument("max_x must be larger than min_b."));
    const int32 offset_x = FloatToQuantizedUnclamped<T>(0.0f, min_x, max_x);
    const int32 offset_y = FloatToQuantizedUnclamped<T>(0.0f, min_y, max_y);
    const T* x_data = x.flat<T>().data();
    const T* y_data = y.flat<T>().data();
    Toutput* z_data = z->flat<Toutput>().data();

    const int ndims = bcast.x_reshape().size();
    if (ndims <= 1) {
      if (x.NumElements() == 1) {
        ScalarMultiply<T, Toutput>(context, y_data, offset_y, y.NumElements(),
                                   x_data[0], offset_x, z_data);
      } else if (y.NumElements() == 1) {
        ScalarMultiply<T, Toutput>(context, x_data, offset_x, x.NumElements(),
                                   y_data[0], offset_y, z_data);
      } else {
        VectorMultiply<T, Toutput>(context, x_data, offset_x, y_data, offset_y,
                                   x.NumElements(), z_data);
      }
    } else if (ndims == 2) {
      const T* vector_data;
      int64 vector_num_elements;
      int32 vector_offset;
      const T* tensor_data;
      int64 tensor_num_elements;
      int32 tensor_offset;
      if (x.NumElements() < y.NumElements()) {
        vector_data = x_data;
        vector_num_elements = x.NumElements();
        vector_offset = offset_x;
        tensor_data = y_data;
        tensor_num_elements = y.NumElements();
        tensor_offset = offset_y;
      } else {
        vector_data = y_data;
        vector_num_elements = y.NumElements();
        vector_offset = offset_y;
        tensor_data = x_data;
        tensor_num_elements = x.NumElements();
        tensor_offset = offset_x;
      }
      VectorTensorMultiply<T, Toutput>(
          vector_data, vector_offset, vector_num_elements, tensor_data,
          tensor_offset, tensor_num_elements, z_data);
    } else {
      LOG(INFO) << "ndims=" << ndims;
      LOG(INFO) << "bcast.x_reshape()="
                << TensorShape(bcast.x_reshape()).DebugString();
      LOG(INFO) << "bcast.y_reshape()="
                << TensorShape(bcast.y_reshape()).DebugString();
      LOG(INFO) << "bcast.x_bcast()="
                << TensorShape(bcast.x_bcast()).DebugString();
      LOG(INFO) << "bcast.y_bcast()="
                << TensorShape(bcast.y_bcast()).DebugString();

      context->SetStatus(errors::Unimplemented(
          "Broadcast between ", context->input(0).shape().DebugString(),
          " and ", context->input(1).shape().DebugString(),
          " is not supported yet."));
      return;
    }

    float min_z_value;
    float max_z_value;
    QuantizationRangeForMultiplication<T, T, Toutput>(
        min_x, max_x, min_y, max_y, &min_z_value, &max_z_value);
    Tensor* z_min = nullptr;
    OP_REQUIRES_OK(context, context->allocate_output(1, {}, &z_min));
    z_min->flat<float>()(0) = min_z_value;

    Tensor* z_max = nullptr;
    OP_REQUIRES_OK(context, context->allocate_output(2, {}, &z_max));
    z_max->flat<float>()(0) = max_z_value;
  }