bug#28971: 24.4; Gnus TLS/SSL POP issue

[Emanuel Berg]

There was a discussion on
gmane.emacs.gnus.general about this bug or
problem. Best probably just to check it out
there. Otherwise I had it appended to a file
and made some edits to make it more clear -
here it is

Something happened to my Gnus. Or the
remote connection?

Now when I do `gnus-group-get-new-news' Gnus
hangs until I do C-g.

The broken POP processes pile up at
`list-processes'.

> Maybe confirm that POP access works from the
> command line first?
> https://unix.stackexchange.com/questions/201818/checking-pop-mail-account-using-terminal

Error according to socat, works with openssl.

test-zoho () { local server=pop.zoho.com local
port=995 socat - OPENSSL:${server}:${port} echo
"socat done" openssl s_client -quiet -connect
${server}:${port} echo "openssl done" }

$ test-zoho

2017/10/20 17:54:09 socat[29967]
E SSL_connect(): error:14090086:SSL
routines:SSL3_GET_SERVER_CERTIFICATE:certificate
verify failed socat done depth=2 C = US, O =
"thawte, Inc.", OU = Certification Services
Division, OU = "(c) 2006 thawte, Inc. - For
authorized use only", CN = thawte Primary Root
CA verify return:1 depth=1 C = US, O = "thawte,
Inc.", OU = Domain Validated SSL, CN = thawte
DV SSL CA - G2 verify return:1 depth=0 CN =
*.zoho.com verify return:1 +OK POP3
mx.zohomail.com v1.0 server ready
<10427.1508514850321@mx.zohomail.com> user XYZ
+OK pass ABC +OK quit +OK mx.zohomail.com
Service closing transmission channel openssl
done

> Error according to socat, works with openssl.
> test-zoho () { local server=pop.zoho.com local port=995 socat - 
> OPENSSL:${server}:${port} echo "socat done" openssl s_client -quiet -connect 
> ${server}:${port} echo "openssl done" }
> $ test-zoho
> 2017/10/20 17:54:09 socat[29967] E SSL_connect(): error:14090086:SSL 
> routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed socat done 
> depth=2 C = US, O = "thawte, Inc.", OU = Certification Services Division, OU 
> = "(c) 2006 thawte, Inc. - For authorized use only", CN = thawte Primary Root 
> CA verify return:1 depth=1 C = US, O = "thawte, Inc.", OU = Domain Validated 
> SSL, CN = thawte DV SSL CA - G2 verify return:1 depth=0 CN = *.zoho.com 
> verify return:1 +OK POP3 mx.zohomail.com v1.0 server ready 
> <10427.1508514850321@mx.zohomail.com> user XYZ +OK pass ABC +OK quit +OK 
> mx.zohomail.com Service closing transmission channel openssl done

Unfortunately I don't know too much about tls,
and will be of limited help here, but my guess
is there's something slightly wrong with the
pop.zoho.com certificate, something that
openssl is letting slide, but socat and gnutls
aren't happy about.

> my guess is there's something slightly wrong
> with the pop.zoho.com certificate, something
> that openssl is letting slide, but socat and
> gnutls aren't happy about.

What exactly is openssl? Can I use that instead
of gnutls?

>> my guess is there's something slightly wrong
>> with the pop.zoho.com certificate, something
>> that openssl is letting slide, but socat and
>> gnutls aren't happy about.
> What exactly is openssl? Can I use that
> instead of gnutls?

My understanding (and again, I know very little
about these things) is that the two programs
are roughly equivalent: they handle creating
and checking TLS certificates, and creating and
handling TLS-encrypted connections to
remote servers.

I actually was just assuming you are using
gnutls, you can probably check the
libgnutls-version. You can also try setting
gnutls-log-level to 3 or 4 and fetching mail,
and see if anything interesting pops up in
*Messages*.

The bad news is that I tried this:

gnutls-cli --port 995 pop.zoho.com

And it connected just fine. You might try that,
and going through with the login procedure.

> the two programs are roughly equivalent: they
> handle creating and checking TLS
> certificates, and creating and handling
> TLS-encrypted connections to remote servers.

OK, then how do I specify openssl should be
used instead? Worth a shot... A search with
`apropos-value' and "gnutls" reveals

    starttls-gnutls-program "gnutls-cli"

    tls-program ("gnutls-cli --insecure -p %p
%h" "gnutls-cli --insecure -p %p %h --protocols
ssl3" "openssl s_client -connect %h:%p -no_ssl2
-ign_eof")

Neither set by me, but can be incorrect anyway,
of course. Eheh.

> I actually was just assuming you are using
> gnutls, you can probably check the
> libgnutls-version.

If you mean ... then:

    $ gnutls-cli --version gnutls-cli 3.3.8

> You can also try setting gnutls-log-level to
> 3 or 4 and fetching mail, and see if anything
> interesting pops up in *Messages*.

This does, over and over again:

    gnutls.c: [3] ASSERT: gnutls_buffers.c:547

    gnutls.c: [3] (Emacs) retry: Resource
temporarily unavailable, try again. gnutls.c:
[1] (Emacs) non-fatal error: Resource
temporarily unavailable, try again. gnutls.c:
[3] ASSERT: gnutls_buffers.c:1104

> The bad news is that I tried this:
> gnutls-cli --port 995 pop.zoho.com
> And it connected just fine. You might try
> that, and going through with the
> login procedure.

Login procedure works, the rest seems fine (?).

>> the two programs are roughly equivalent:
>> they handle creating and checking TLS
>> certificates, and creating and handling
>> TLS-encrypted connections to remote servers.
> OK, then how do I specify openssl should be
> used instead? Worth a shot... A search with
> `apropos-value' and "gnutls" reveals

>     starttls-gnutls-program "gnutls-cli"
> tls-program ("gnutls-cli --insecure -p %p %h"
> "gnutls-cli --insecure -p %p %h --protocols
> ssl3" "openssl s_client -connect %h:%p
> -no_ssl2 -ign_eof")

Maybe change this variable so that only the
"openssl" string is in there?

> If you mean ... then:
> $ gnutls-cli --version gnutls-cli 3.3.8

I meant that if the variable libgnutls-version
was non-nil, it probably meant you were using
gnutls. But the variables you found above are
more relevant.

>> You can also try setting gnutls-log-level to
>> 3 or 4 and fetching mail, and see if
>> anything interesting pops up in *Messages*.
>
> This does, over and over again:
>
> gnutls.c: [3] ASSERT: gnutls_buffers.c:547
>
> gnutls.c: [3] (Emacs) retry: Resource
> temporarily unavailable, try again.
> gnutls.c: [1] (Emacs) non-fatal error:
> Resource temporarily unavailable, try again.
> gnutls.c: [3] ASSERT: gnutls_buffers.c:1104
> The bad news is that I tried this:
>> gnutls-cli --port 995 pop.zoho.com

>> And it connected just fine. You might try
>> that, and going through with the login
>> >procedure.
>
> Login procedure works, the rest seems fine
> (?).

Another post on the topic:

I'm gonna use this thread to dump everything
related to this issue. At least then I have it
all in one place.

I've had the issue for several years off and
on, on several computers even with slightly
different OSs (Debian and Raspbian) so it is
starting to get embarrassing.

    Mail source (pop :user XYZ :password ABC
:server pop.zoho.com :port 995 :stream ssl)
failed: (error USER XYZ not valid)

and

    gnutls.c: [0] (Emacs) fatal error: The TLS
connection was non-properly terminated.




In GNU Emacs 24.4.1 (arm-unknown-linux-gnueabihf, GTK+ Version 3.14.5)
 of 2015-03-10 on bm-wb-01, modified by Debian
System Description:     Raspbian GNU/Linux 8.0 (jessie)

Configured using:
 `configure --build arm-linux-gnueabihf
 --prefix=/usr --sharedstatedir=/var/lib
 --libexecdir=/usr/lib --localstatedir=/var/lib
 --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 
--enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.4/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.4/site-lisp:/usr/share/emacs/site-lisp
 --build arm-linux-gnueabihf --prefix=/usr
 --sharedstatedir=/var/lib
 --libexecdir=/usr/lib --localstatedir=/var/lib
 --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 
--enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.4/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.4/site-lisp:/usr/share/emacs/site-lisp
 --with-x=yes --with-x-toolkit=gtk3
 --with-toolkit-scroll-bars 'CFLAGS=-g -O2
 -fstack-protector-strong -Wformat
 -Werror=format-security -Wall'
 CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-z,relro'

Important settings:
  value of $LANG: en_GB.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Text

Minor modes in effect:
  show-paren-mode: t
  shell-dirtrack-mode: t
  erc-list-mode: t
  erc-menu-mode: t
  erc-autojoin-mode: t
  erc-ring-mode: t
  erc-networks-mode: t
  erc-pcomplete-mode: t
  erc-track-mode: t
  erc-track-minor-mode: t
  erc-match-mode: t
  erc-button-mode: t
  erc-fill-mode: t
  erc-stamp-mode: t
  erc-netsplit-mode: t
  erc-irccontrols-mode: t
  erc-noncommands-mode: t
  erc-move-to-prompt-mode: t
  erc-readonly-mode: t
  erc-scrolltobottom-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  global-font-lock-mode: t
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  auto-composition-mode: t
  auto-compression-mode: t
  auto-fill-function: do-auto-fill
  transient-mark-mode: t
  abbrev-mode: t

Recent input:
C-n C-n C-n C-n C-n C-n C-n C-n C-p C-p C-p C-p C-p 
C-p C-n C-n C-n C-n C-n C-n C-n C-p C-p RET C-p C-p 
ESC q C-n > > C-d C-d C-p ESC q C-n C-n C-n C-n C-n 
C-n C-n C-p C-p C-p C-p C-k C-n C-n C-n C-n C-n C-n 
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-n C-n C-n C-n C-n C-p C-p C-p C-p C-p C-p C-p C-p 
C-p C-p C-p C-p RET ESC q C-n C-f SPC C-b > C-p ESC 
q C-n C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f 
C-f C-n C-b C-f DEL RET RET > DEL C-n C-d C-d C-d C-p 
C-n C-d C-p > > DEL C-n C-b > SPC C-p C-b SPC C-p C-k 
RET C-p > C-n C-a ESC q C-e C-n C-n C-n C-a ESC q C-n 
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-p C-p 
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C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-n C-n C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p 
C-p C-p C-p C-p C-p C-p C-p C-p C-e RET RET A n o t 
h e r SPC p o s t SPC o n t SPC DEL DEL SPC t h e SPC 
t o p i o DEL c s DEL : C-x C-s C-o i C-o e i i SPC 
SPC C-o i C-n C-n C-n C-n C-n C-p C-p C-p C-p C-p C-p 
C-p C-p C-p C-p C-@ C-o C-k C-@ C-o k ESC w C-o i ESC 
x r e p o r t - b u g RET

Recent messages:
Starting new Ispell process [ispell::american-insane] ...
Spell-checking error-processed.txt using ispell with american-insane 
dictionary...
Personal dictionary saved.
Spell-checking error-processed.txt using ispell with american-insane 
dictionary...done
Mark set
Mark activated
C-o C-k is undefined
Mark activated
Saved text from "Something happened to my Gnus. Or the
re"

Load-path shadows:
/usr/share/emacs/24.4/site-lisp/debian-startup hides 
/usr/share/emacs/site-lisp/debian-startup
./help hides /usr/share/emacs/24.4/lisp/help
~/.emacs.d/emacs-init/misc hides /usr/share/emacs/24.4/lisp/misc
/usr/share/emacs24/site-lisp/flim/md4 hides /usr/share/emacs/24.4/lisp/md4
/usr/share/emacs24/site-lisp/flim/hex-util hides 
/usr/share/emacs/24.4/lisp/hex-util
~/.emacs.d/lisp/abbrev hides /usr/share/emacs/24.4/lisp/abbrev
~/.emacs.d/emacs-init/gnus/server hides /usr/share/emacs/24.4/lisp/server
/usr/share/emacs24/site-lisp/dictionaries-common/ispell hides 
/usr/share/emacs/24.4/lisp/textmodes/ispell
/usr/share/emacs24/site-lisp/dictionaries-common/flyspell hides 
/usr/share/emacs/24.4/lisp/textmodes/flyspell
/usr/share/emacs24/site-lisp/flim/sasl-ntlm hides 
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/usr/share/emacs24/site-lisp/flim/sasl-cram hides 
/usr/share/emacs/24.4/lisp/net/sasl-cram
/usr/share/emacs24/site-lisp/flim/ntlm hides /usr/share/emacs/24.4/lisp/net/ntlm
/usr/share/emacs24/site-lisp/flim/sasl hides /usr/share/emacs/24.4/lisp/net/sasl
/usr/share/emacs24/site-lisp/flim/hmac-def hides 
/usr/share/emacs/24.4/lisp/net/hmac-def
/usr/share/emacs24/site-lisp/flim/hmac-md5 hides 
/usr/share/emacs/24.4/lisp/net/hmac-md5
/usr/share/emacs24/site-lisp/flim/sasl-digest hides 
/usr/share/emacs/24.4/lisp/net/sasl-digest

Features:
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Memory information:
((conses 8 549625 85419)
 (symbols 24 51306 0)
 (miscs 20 815 4121)
 (strings 16 137215 11969)
 (string-bytes 1 4128153)
 (vectors 8 52408)
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 (heap 1024 39263 71394))

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