bug#51327: 28.0.60; emacsclient warns about XDG_RUNTIME_DIR when starting daemon on-demand

[Paul Eggert]

On 12/7/21 22:57, Jim Porter wrote:
> Doing that by default opens a loophole for all emacsclient users, but 
> what about a command-line flag like `emacsclient 
> --allow-tmpdir-loophole' and/or an environment variable like 
> `EMACS_ALLOW_TMPDIR_LOOPHOLE=1 emacsclient' (with a better name, of 
> course)? Then, the default behavior would be free of loopholes[2], but 
> Ulrich's case could be achieved by passing that flag when calling 
> emacsclient. It might even be possible for Gentoo to enable that for the 
> user in the appropriate cases...

Yes, I think something like this would be OK. The command-line flag 
would be easier to audit.

Not sure whether a last-minute change like this should go into Emacs 28, 
though, even though it's security-relevant. Eli would be a better judge 
of that.