CODEWITHSUNDEEP
c++native
a n
a n

Reputation: 13

HEAP CORRUPTION DETECTED: after normal block... CRT detected that the application worte to memory after end of heap buffer

When I run this code, I get the error in the title, here's an exact screenshot:

enter image description here

My code is this :

string ProcessCommand(vector<unsigned char> data)
{
    try
    {
        int valread = data.size();
        unsigned char* converted = &data[0];
        char *buffer = (char *)converted;
        buffer[valread] = '\0';
        const char file[] = ">myfile.txt";
        char * newBuffer = new char[strlen(buffer) + strlen(file) + 1];
        strcpy(newBuffer, buffer);
        strcat(newBuffer, file);
        system(newBuffer);
        fstream f("myfile.txt", fstream::in);
        string str;
        getline(f, str, '\0');
        //const char * sendfile = str.c_str();
        //char * result;
        //result = const_cast<char *>(sendfile);
        f.close();
        remove("myfile.txt");
        return str;
    }
    catch (const std::exception&)
    {

    }
}

Upvotes: 0

Views: 5351

Answers (1)

Bathsheba
Bathsheba

Reputation: 234795

buffer[valread] = '\0'; is attempting to access an element of buffer that doesn't exist. The program behaviour is therefore undefined.

If you had used data.at(valread) instead then a std::exception would have been thrown (and intercepted at your catch site), as required by the C++11 standard.

Also consider using the + overload of std::string for all your concatenations. Your code will be so much more readable if you do that. Use a std::string type for newBuffer (with automatic storage duration) as well. You can always use c_str() to access the internal data buffer on a read-only basis.

Upvotes: 4

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