System Information

OpenCV version: 4.6.0
Operating System / Platform: Ubuntu 22.04
Compiler & compiler version: gcc-11.3.0

Detailed description

We find an infinite loop when calling the function "cv::dnn::readNetFromTensorflow(input_file)". When the function read our input_file, it hangs and cannot terminate. We found that it stuck in a loop (located in cv::dnn::dnn4_v20220524::RemoveIdentityOps line 833-840 ). The vulnerable code is listed as follows:

                while (true)
                {
                    IdentityOpsMap::iterator nextIt = identity_ops.find(it->second);
                    if (nextIt != identity_ops.end())
                        it = nextIt;
                    else
                        break;
                }

By our debug, the iterator "nextIt" displayed as "nextIt = {first = "", second = ""}" as the loop execution, namely "first = second" in the map iterator. Once the map identity_ops.find(it->second) executed, "nextIt" will cyclically assigned by "", by which the loop cannot terminate.

Steps to reproduce

To reproduce the bug, only need to call the function readNetFromTensorflow(repo) by our reproduce file . The reproduce file repro. We triggered the bug by the following simple code:

#include <opencv2/dnn/dnn.hpp>

using namespace cv;
using namespace dnn;

int main(int argc, char* argv[]){
  try {
    readNetFromTensorflow((const char*)argv[1]);
  } catch (std::exception &e) {}
return 1;
}

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files (videos, images, onnx, etc)