Dear Maintainer,

When debsigs creates its temporary directory, it just uses
"/tmp/debsigndeb.$$" where "$$" is the process ID.  Using a predictable
temporary file name can be a security issue if an attacker is able to
create the path first.  However, Since debsig uses a temporary directory,
not a file, only a denial of service attack is possible.

It would be safer to use the built-in mkdtemp() function when creating
the temporary directory, which creates a random name and will retry
as needed if the chose name already exists.

The attached fix is also in gitlab as:
https://gitlab.com/debsigs/debsigs/-/merge_requests/2

 - todd

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