How to generate random file name for socket under Linux?

Question

I want to make a small program which use local namespace socket and I will need to use temporary file name as address of the socket.

So how to generate random file name under Linux?

+ I'm using the C programming language under Debian Linux.
+ Acoording to the GNU C Library Reference,tmpname is not safe.But the safe ones tmpfile and mkstemp create and open the generated file.Is there any safe and non-create-open to this.In other words, the function should forbidden any other request to create the generated file name under specific directory.

thanks.

Answer 1

If you're doing this in C, use mkdtemp to create a directory, and put your socket inside this directory.

Other functions such as tmpnam or mktemp are insecure; since they don't create and open the temp file for you, it's easy to be vulnerable to following a pre-existing symlink (placed by an attacker who guessed your temp filename) to some important file (like /etc/passwd), overwriting it.

Note that there's no way to 'lock' a path - all you can do is create something there. If you need to put a socket there eventually, using a directory as a placeholder is your best bet.