bug#36154: 26.2; read-passwd function creates a security issue

[Phil Sainty <psainty@orcon.net.nz>]

On 2019-10-10 12:25, Lars Ingebrigtsen wrote:
> I think it makes sense to allow users to do this -- this is something
> that should be up to them whether to do or not.  So I'm closing this 
> bug
> report.  If anybody disagrees with this, please feel free to reopen.

A potential solution to this would to make the low-level kill functions
respect a new `inhibit-kill-ring' variable, such that nothing would be
added to the kill ring if that was non-nil.

A user option for the password entry routine could then be added to 
control
whether or the variable was set by `read-passwd' when setting up the
minibuffer.

This facility might also have more general applicability, and perhaps
even warrant a minor mode.  I can certainly envisage `inhibit-kill-ring'
being let-bound by users for specific cases, if they consider that 
unwanted
kill ring pollution was occurring.


-Phil