使用 Boost C++ 清理主机名

Question

我试图将主机名/ipv4/ipv6 传递给 linux 中的 ping 实用程序（以避免使用原始套接字、root），但是，我想在运行命令之前确保它是有效的。例如，如果提供了恶意域名，比如

char host[] = "google.com;cat > pwned.txt";

消毒剂应该拒绝它，因为它会允许远程代码执行

ping -c 4 google.com;cat > pwned.txt

到目前为止，我已经在下面编写了代码来检测有效的 ipv4、ipv6 和主机名。

问题

代码有异味，所以我想知道是否有更好的 Boost C++ 方法来清理用户输入？

#include <iostream>
#include <string>
#include <algorithm> 
#include <boost/asio.hpp>

int main(int argc, char* argv[])
{
    //char host[] = "google.com";
    char host[] = "google.com;cat > pwned.txt";

    std::string allowed = "1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-.";

    bool bValid = false;
    boost::asio::ip::address ipv4Addr;
    boost::asio::ip::address ipv6Addr;

    try
    {
        ipv4Addr = boost::asio::ip::address::from_string(host);
        bValid = ipv4Addr.is_v4();
    }
    catch (std::exception& e)
    {
        std::cerr << "NOT ipv4: " << e.what() << std::endl;
        bValid = false;
    }

    if (!bValid)
    {
        // not ipv4, let's try ipv6
        try
        {
            ipv6Addr = boost::asio::ip::address::from_string(host);
            bValid = ipv6Addr.is_v6();
        }
        catch (std::exception& e)
        {
            std::cerr << "NOT ipv6: " << e.what() << std::endl;
            bValid = false;
        }

        if (!bValid)
        {   
            // ipv4 and ipv6 failed, try a string
            std::string hostname = std::string(host);
            if (hostname.find_first_not_of(allowed) != std::string::npos) {
                std::cerr << "NOT valid host" << std::endl;
                return 1;
            }
        }
    }

    std::string sCommand = "ping -c 4 ";
    sCommand.append(host);
    std::cout << "Running PING command: " << sCommand << std::endl;
    int result = std::system(sCommand.c_str());
    if (result != 0) {
        std::cerr << "Command failed: " << result << std::endl;
    }

    return 0;
}

Answer 1

就像其他人说的那样，不要消毒，只是不要不安全地传递论点。您的 ping 工具已经清理完毕，并且您从未调用过 shell。

#include <boost/process.hpp>
#include <iostream>
namespace bp = boost::process;

int main(int argc, char** argv) {
    if (argc > 1) {
        std::error_code ec;
        int code = bp::system(bp::search_path("ping"), "-c", "4", argv[1], ec);
        std::cout << code << " (" << ec.message() << ")\n";
    }
}