Re: emacs-29 3c1693d08b0: Fix Elisp code injection vulnerability in emacsclient-mail.desktop

[Robert Pluim <rpluim@gmail.com>]

>>>>> On Wed, 8 Mar 2023 10:54:08 -0800, Jim Porter <jporterbugs@gmail.com> said:

    Jim> 'set-arg' is probably simple enough that we could expect users to
    Jim> write it themselves. '--apply' is a bit tricky (for emacsclient at
    Jim> least), since we'd need to properly escape strings. I guess the
    Jim> complexity of doing this would depend on how we did the escaping
    Jim> though.

Iʼm not sure what escaping is needed. We take each command line
argument and pass it to emacs wrapped in "" so itʼs treated as a
string.

    Jim> For reference for this thread, the conclusion we came to in bug#57752
    Jim> was an interface like this:

    Jim>   emacs --apply func1 arg1 arg2 -- --apply func2 arg3 arg4

    Jim> (Ditto for emacsclient.)

Thatʼs not that easy to do with our current usage of getopt. For
emacsclient, OTOH, the following is pretty easy to support without any
changes to server.el

    emacsclient --apply func arg1 arg2

since --apply can (ab)use --eval internally.

Robert
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