// curl_http2_tunnel_mixup.c - Simulated libcurl handling CONNECT over HTTP/2
#include <stdio.h>
void handle_http2_stream(int stream_id) {
    // Vulnerability: after CONNECT, the proxy mixes streams with the tunneled data
    if (stream_id == 0) {
        printf("CONNECT to target\n");
    } else {
        // Data from another stream may leak into the tunnel
        printf("Stream %d data crosses tunnel boundary\n", stream_id);
    }
}
int main() {
    handle_http2_stream(0);
    handle_http2_stream(1);  // should be isolated
    return 0;
}

gcc -o curl_http2_tunnel curl_http2_tunnel_mixup.c
./curl_http2_tunnel