$符号导致程序崩溃

Question

Here is my program:

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <iostream>
int main()
{
    std::string hash = crypt("asd123","$2a$13$IP4FT4gf123I5bT6o4123123123123nbEXFqo.Oa123");
    std::cout << hash;
}

Running this causes the error

terminate called after throwing an instance of 'std::logic_error' what(): basic_string::_M_construct null not valid Aborted (core dumped)

but if I remove the $ from the salt it runs fine.

Answer 1

The error message tells you that crypt returns a nullpointer for the given arguments. Most likely that's its way to signal failure. You need to check for that.

You can find out more about crypt by (1) finding documentation of the function, and (2) reading it.

For example, you can google “unistd crypt”.

And it so happens that the documentation specifies the valid set of characters you can use, in a nice table.