5 ms·

Ok added to the todo list

• wutwot 14y ago
  You don't filter out CPP macro's. I would skip that and only allow C code. Or run this thing in a proper jail because at the moment: - doing an include #include "/dev/random" will block the thread. - including "/etc/passwd" is also possible although I don't see a direct way to turn this into password disclosure. Seriously; even if it's a weekend project, letting people run all kinds of potentially bad code on your machine is never a good idea. Even though you don't run the binaries yourself there's so many ways to mess around with a compiler. You just don't know what's going to happen.
  • __alexs 14y ago
    chroot would probably be sufficient. Barring some sort of code execution vuln in the compiler you can only load stuff off of the filesystem. Having the actual CPP available is nice because some bits of libc are only macros.
  • ynh 14y ago
    I have now added some basic macro detection
    • yonilevy 14y ago
      #define x "/etc/passwd" #include x
      • ynh 14y ago
        I have now fixed it. But I think there must be an other way to make it safe. Maybe a sandbox
        • espes 14y ago
          If it's a server used for other things, definitely a sandbox. gcc's not exactly security hardend. Best one (novel solution, though the code's old and shit) I've come across: https://pts-mini-gpl.googlecode.com/svn/trunk/uevalrun/doc/uevalrun.html https://pts-mini-gpl.googlecode.com/svn/trunk/uevalrun/doc/u...
        • dzorz 14y ago
          This is part of your /etc/shadow file: root:censored We can still read /etc/ssh/ssh_host_rsa_key, etc. Edit: removed hash, sorry
          • daeken 14y ago
            Saying "you can read /etc/shadow by doing X, Y, and Z" is okay -- it's a permanent record there was a flaw. Saying "here's your root password hash" is not ok; even once the flaw is fixed, that hash is still floating around out there. I'd take advantage of the edit period and remove that from your comment; it's just not cool. The OP should definitely change the root password on the box regardless.
          • ynh 14y ago
            No problem I think I could fix it. Can you show us how you read the content of the file. Just want to learn more
          • wulczer 14y ago
            Well one easy way to increase security would for this to stop running as root. Please, don't ever run your application code as root. Less so when it's facing the Internet.
        • ynh 14y ago
          I have now used a the wrapper by gcc-explorer https://github.com/mattgodbolt/gcc-explorer/blob/master/c-preload/preload.c https://github.com/mattgodbolt/gcc-explorer/blob/master/c-pr...
      • deleted 14y ago
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