bug#15648: 24.2.50; gnutls SSL connection to IMAP server causes emacs to crash completely

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Please describe exactly what actions triggered the bug, and
the precise symptoms of the bug.  If you can, give a recipe
starting from `emacs -Q':

I am using gnutls within the vm (viewmail) mail reader (vm-version
8.2.0b) to read email over IMAP-SSL under nt Emacs 24.2.50.1 in
Windows 7

Emacs gives me the following error in the message line before immediately
crashing the entire emacs process:
GnuTLS error: #<proces IMAP over SSL>, -64

The Windows crash both then gives me the following error:
Problem signature:
  Problem Event Name:   APPCRASH
  Application Name:             emacs.exe
  Application Version:  24.2.50.0
  Application Timestamp:                5037d090
  Fault Module Name:                    libgnutls-28.dll
  Fault Module Version:                 0.0.0.0
  Fault Module Timestamp:               501d8392
  Exception Code:                               c0000005
  Exception Offset:                             0000657e
  OS Version:                                   6.1.7601.2.1.0.768.3
  Locale ID:                                    1033
  Additional Information 1:             0a9e
  Additional Information 2:             0a9e372d3b4ad19135b953a78882e789
  Additional Information 3:             0a9e
  Additional Information 4:             0a9e372d3b4ad19135b953a78882e789

I do not believe this is a problem with vm (viewmail) since all works
well when I use an external program (stunnel) to create the SSL
tunnel. The problem only happens when I use the internal GNUtls
capability to create the SSL tunnel.

Even so, it is surprising to me that the entire Emacs app crashes - I
have beena heavy Emacs user since 1984 and I don't believe I have ever
had it crash! (kudos to emacs for reliability)


Debugging wasn't easy since I needed to 'catch' it right before the
crash and set a breakpoint there. It turns out that it crashes when
evaluating the declared c-function "gnutls-boot" which is an argument
to "gnutls-message-maybe" called from the function gnutls-negotiate in
gnutls.el

  (gnutls-boot process type params)
where:
                process = #<process IMAP over SSL>
                type    = gnutls-x509pki
                params = (:priority "NORMAL" :hostname "imap.mydomain.org" 
:loglevel 0 :min-prime-bits 256 :trustfiles ("/usr/ssl/certs/ca-bundle.crt") 
:crlfiles nil :keylist nil :verify-flags nil :verify-error nil 
:verify-hostname-error nil :callbacks nil)
  
  (gnutls-boot gnutls-x509pki

Here is what I got from the Emacs debugger:

* (gnutls-boot process type params)
* (setq ret (gnutls-boot process type params))
* (gnutls-message-maybe (setq ret (gnutls-boot process type params)) "boot: %s" 
params)
  (let* ((type (or type (quote gnutls-x509pki))) (trustfiles (or trustfiles 
(delq nil (mapcar (lambda (f) (and f ... f)) (if (functionp gnutls-trustfiles) 
(funcall gnutls-trustfiles) gnutls-trustfiles))))) (priority-string (or 
priority-string (cond ((eq type (quote gnutls-anon)) 
"NORMAL:+ANON-DH:!ARCFOUR-128") ((eq type (quote gnutls-x509pki)) (if 
gnutls-algorithm-priority (upcase gnutls-algorithm-priority) "NORMAL"))))) 
(min-prime-bits (or min-prime-bits gnutls-min-prime-bits)) (params (\` 
(:priority (\, priority-string) :hostname (\, hostname) :loglevel (\, 
gnutls-log-level) :min-prime-bits (\, min-prime-bits) :trustfiles (\, 
trustfiles) :crlfiles (\, crlfiles) :keylist (\, keylist) :verify-flags (\, 
:min-prime-bits (\, min-prime-bits) :trustfiles (\, trustfiles) :crlfiles (\, 
crlfiles) :keylist (\, keylist) :verify-flags (\, verify-flags) :verify-error 
(\, verify-error) :verify-hostname-error (\, verify-hostname-error) :callbacks 
nil))) ret) (edebug) (gnutls-message-maybe (setq ret (gnutls-boot process type 
params)) "boot: %s" params) (when (gnutls-errorp ret) (signal (quote 
gnutls-error) (list process ret))) process))
  (cl--block-wrapper (catch (quote --cl-block-gnutls-negotiate--) (let* ((type 
(or type (quote gnutls-x509pki))) (trustfiles (or trustfiles (delq nil (mapcar 
... ...)))) (priority-string (or priority-string (cond (... 
"NORMAL:+ANON-DH:!ARCFOUR-128") (... ...)))) (min-prime-bits (or min-prime-bits 
gnutls-min-prime-bits)) (params (\` (:priority (\, priority-string) :hostname 
(\, hostname) :loglevel (\, gnutls-log-level) :min-prime-bits (\, 
min-prime-bits) :trustfiles (\, trustfiles) :crlfiles (\, crlfiles) :keylist 
(\, keylist) :verify-flags (\, verify-flags) :verify-error (\, verify-error) 
:verify-hostname-error (\, verify-hostname-error) :callbacks nil))) ret) 
(edebug) (gnutls-message-maybe (setq ret (gnutls-boot process type params)) 
"boot: %s" params) (when (gnutls-errorp ret) (signal (quote gnutls-error) (list 
process ret))) process)))
  (cl-block gnutls-negotiate (let* ((type (or type (quote gnutls-x509pki))) 
(trustfiles (or trustfiles (delq nil (mapcar (lambda ... ...) (if ... ... 
gnutls-trustfiles))))) (priority-string (or priority-string (cond ((eq type 
...) "NORMA spec)))) (hostname (car (cdr (memq (quote :hostname) spec)))) 
(priority-string (car (cdr (memq (quote :priority-string) spec)))) (trustfiles 
(car (cdr (memq (quote :trustfiles) spec)))) (crlfiles (car (cdr (memq (quote 
:crlfiles) spec)))) (keylist (car (cdr (memq (quote :keylist) spec)))) 
(min-prime-bits (car (cdr (memq (quote :min-prime-bits) spec)))) (verify-flags 
(car (cdr (memq (quote :verify-flags) spec)))) (verify-error (car (cdr (memq 
(quote :verify-error) spec)))) (verify-hostname-error (car (cdr (memq (quote 
:verify-hostname-error) spec))))) (cl-block gnutls-negotiate (let* ((type (or  
gnutls-negotiate(:process #<process IMAP over SSL> :type gnutls-x509pki 
:hostname "imap.mydomain.org")
  open-gnutls-stream("IMAP over SSL" #<buffer trace of IMAP over SSL session to 
imap.mydomain.org at 14:12:31> "imap.mydomain.org" 993)
  funcall(open-gnutls-stream "IMAP over SSL" #<buffer trace of IMAP over SSL 
session to ko  (  (  (with-  network-stream-open-tls("IMAP over SSL" #<buffer 
trace of IMAP over SSL session to imap.mydomain.org at 14:12:31> 
"imap.mydomain.org" 993 (:type tls))
  funcall(network-stream-open-tls "IMAP over SSL" #<buffer trace of IMAP over 
SSL session   (unwind-pr  (let ((work-buffer (or buffer (generate-new-buffer " 
*stream buffer*"))) (fun (cond ((and (e  (if (and (not return-list) (or (eq  
(let ((type (plist-get parameters :type)) (return-list (plist-get parameters 
:return-list))) (if (and (not return-list) (or (eq type (quote plain)) (an  
open-network-stream("IMAP over SSL" #<buffer trace of IMAP over SSL session to 
imap.mydomain.org at 14:12:31> "  byte-code("203+L:+ANON-DH:!ARCFOUR-128") ((eq 
type ...) (if gnutls-algorithm-priority ... "NORMAL"))))) (min-prime-bits (or 
min-prime-bits gnutls-min-prime-bits)) (params (\` (:priority (\, 
priority-string) :hostname (\, hostname) :loglevel (\, gnutls-log-level) 
:min-prime-bits (\, min-prime-bits) :trustfiles (\, trustfiles) :crlfiles (\, 
crlfiles) :keylist (\, keylist) :verify-flags (\, verify-flags) :verify-error 
(\, verify-error) :verify-hostname-error (\, verify-hostname-error) :callbacks 
nil))) ret) (edebug) (gnutls-message-maybe (setq ret (gnutls-boot process type 
params)) "boot: %s" params) (when (gnutls-errorp ret) (signal (quote 
gnutls-error) (list process ret))) process))
  (let* ((process (car (cdr (memq (quote :process) spec)))) (type (car (cdr 
(memq (quote :type) verify-flags) :verify-error (\, verify-error) 
:verify-hostname-error (\, verify-hostname-error) :callbacks nil))) ret) 
(edebug) (gnutls-message-maybe (setq ret (gnutls-boot process type params)) 
"boot: %s" params) (when (gnutls-errorp ret) (signal (quote gnutls-error) (list 
process ret))) process)
  (catch (quote --cl-block-gnutls-negotiate--) (let* ((type (or type (quote 
gnutls-x509pki))) (trustfiles (or trustfiles (delq nil (mapcar (lambda ... ...) 
(if ... ... gnutls-trustfiles))))) (priority-string (or priority-string (cond 
((eq type ...) "NORMAL:+ANON-DH:!ARCFOUR-128") ((eq type ...) (if 
gnutls-algorithm-priority ... "NORMAL"))))) (min-prime-bits (or min-prime-bits 
gnutls-min-prime-bits)) (params (\` (:priority (\, priority-string) :hostname 
(\, hostname) :loglevel (\, gnutls-log-level)

----------------------------------

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file
c:/MyPrograms/Emacs/etc/DEBUG.


In GNU Emacs 24.2.50.1 (i386-mingw-nt6.1.7601)
 of 2012-08-24 on YAMALOK
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --with-gcc (4.7) --cflags -m32 -O2 -g0 -march=prescott
 -mtune=prescott -pipe -IC:/gnuwin32/emacs/include
 -IC:/gnuwin32/emacs/lib -IC:/gnuwin32/src -IC:/gnutls/include
 -IC:/gnutls/lib -IC:/gnutls/bin -IC:/libxml2/include -IC:/libxml2/lib
 -IC:/libxml2/bin --ldflags '

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1252
  default enable-multibyte-characters: t

Major mode: VM Summary

Minor modes in effect:
  display-time-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-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

Recent input:
<help-echo> <escape> x r e p <tab> o r <tab> <return> 
s t u n n e l SPC <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> SPC <backspace> <backspace> 
<down-mouse-1> <mouse-1> C-h f g n u t <tab> <tab> 
<tab> a v a i <tab> <return> <help-echo> <help-echo> 
<down-mouse-1> <mouse-2> C-h C-g <escape> x C-g <C-down-mouse-1> 
<drag-mouse-1> <escape> x v m <return> C-g C-h f v 
m <backspace> m <backspace> m - - s t <tab> u <tab> 
<tab> C-g C-h v v m - s t <tab> u <tab> p <tab> <return> 
C-p <escape> x e m a c s = r <backspace> <backspace> 
- r e p <tab> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
r e p o <tab> r t - e m <tab> <return>

Recent messages:
c:/myname/bin/qp-decode.exe exited non-zero (code 123)
Parsing BBDB... (frobnicating...done)
inbox: Checking for new mail...
Decrypting c:/myname/emacs/.authinfo.gpg...0%
Opening input file: Can't decrypt, Cancelled; Exit
Making completion list... [2 times]
Quit
Making completion list...
Type "q" in help window to restore its previous buffer.
Making completion list...

Load-path shadows:
None found.

Features:
(shadow sort pp vm-save tapestry vm-crypto vm-imap jjk-vm dired
vm-mime-display-internal-application vm-ps-print bbdb-vm vm-autoload
bbdb-snarf mail-extr bbdb-autoloads bbdb-hooks bbdb-com cl cl-lib vcard
vm-vcard vm-pine smtpmail bbdb timezone vm-rfaddons vm-menu vm-window
vm-toolbar vm-folder vm-mime vm-undo vm-virtual vm-summary-faces
vm-summary vm-mouse vm-page vm-motion vm-minibuf vm-message vm-misc
vm-macro vm-autoloads vm-vars vm-version vm find-func emacsbug message
idna format-spec rfc822 mml mml-sec mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mail-utils help-mode easymenu jjk-comments jjk-load
ps-print ps-def lpr jjk-print ibm-keymaps jjk-frames jjk-hooks
jjk-keymaps ehelp electric uniquify warnings arc-mode archive-mode
jjk-lib epa-file epa derived epg epg-config advice help-fns
advice-preload auth-source eieio byte-opt bytecomp byte-compile cconv
macroexp gnus-util mm-util mail-prsvr password-cache cygwin-mount
ange-ftp comint ansi-color ring server time time-date tooltip ediff-hook
vc-hooks lisp-float-type mwheel dos-w32 disp-table ls-lisp w32-win
w32-vars tool-bar dnd fontset image regexp-opt fringe tabulated-list
newcomment lisp-mode register page menu-bar rfn-eshadow timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham
georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese hebrew greek romanian slovak czech european ethiopic
indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple
abbrev minibuffer button faces cus-face files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process multi-tty emacs)