bug#45413: Password exposure on SSH login

[Pedro J. V. Mendes]

Within <M-x shell>, on SSH login (e.g.) to sigma.ist.utl.pt, the 
password was
visible during typing and recorded to history (accessible through M-p).


In GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.20, 
cairo version 1.16.0)
 of 2020-11-30 built on lcy01-amd64-021
Repository revision: b65eeac9613c62aaa0e4408dba8d795c07ea1f11
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12008000
System Description: Ubuntu 20.04.1 LTS

Recent messages:
C-x *  (Type ? for a list of Calc options)
Welcome to the GNU Emacs Calculator!  Press ‘?’ or ‘h’ for help, ‘q’ to quit
C-c M-p is undefined
ESC M-p is undefined
History item: 8
History item: 17 [3 times]
History item: 23
History item: 105
Mark saved where search started
~/Programs.dev
Quit
Configured using:
 'configure --prefix=/snap/emacs/current/usr --with-x-toolkit=gtk3
 --without-xaw3d --with-modules --with-cairo
 'CFLAGS=-isystem/build/emacs/parts/emacs/install/usr/include -O2'
 CPPFLAGS=-isystem/build/emacs/parts/emacs/install/usr/include
 'LDFLAGS=-L/build/emacs/parts/emacs/install/lib
 -L/build/emacs/parts/emacs/install/usr/lib
 -L/build/emacs/parts/emacs/install/lib/x86_64-linux-gnu
 -L/build/emacs/parts/emacs/install/usr/lib/x86_64-linux-gnu''

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB NOTIFY
INOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF
ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD
JSON PDUMPER LCMS2 GMP

Important settings:
  value of $LC_CTYPE: pt_PT.UTF-8
  value of $LC_MONETARY: pt_PT.UTF-8
  value of $LC_NUMERIC: pt_PT.UTF-8
  value of $LC_TIME: pt_PT.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Shell

Minor modes in effect:
  shell-dirtrack-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
format-spec rfc822 mml mml-sec password-cache epa derived epg epg-config
gnus-util rmail rmail-loaddefs text-property-search mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils misearch
multi-isearch shell pcomplete comint ansi-color ring calc-misc calc-menu
calc calc-loaddefs calc-macs cl-seq cl-extra help-mode seq byte-opt gv
bytecomp byte-compile cconv mule-util jka-compr info easymenu desktop
frameset time-date subr-x cl-loaddefs cl-lib tooltip eldoc electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame minibuffer cl-generic cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms
cp51932 hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese composite charscript charprop case-table epa-hook
jka-cmpr-hook help simple abbrev obarray cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads dbusbind inotify lcms2 dynamic-setting
system-font-setting font-render-setting cairo move-toolbar gtk x-toolkit
x multi-tty make-network-process emacs)

Memory information:
((conses 16 78891 11520)
 (symbols 48 8571 1)
 (strings 32 24487 1987)
 (string-bytes 1 741438)
 (vectors 16 13491)
 (vector-slots 8 177087 12800)
 (floats 8 51 33)
 (intervals 56 970 0)
 (buffers 1000 17))