bug#7438: 23.2; [PATCH] lisp/gnus/pop3.el fix STLS command ordering

bug#7438: 23.2; [PATCH] lisp/gnus/pop3.el fix STLS command ordering

[Yuri Karaban]

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Hi

Starttls (STLS) is not working with pop3.

There is a bug in current implementation.

Current implementation sends STLS just after opening connection.

As result connection hangs (pop3.el tries to read a greeting message
after STLS, but all POP3 servers I tried does not send anything after
successful negotiation). On other hand, ignoring server greeting leads
to mistreating server greeting (+OK <timestamp>) as successful response
to STLS command. In this case negotiation starts too early (before
reading real response to STLS).

I've attached a patch which fixes the problem. The server greeting got
read first (as with plain POP3) and only after receiving greeting STLS
issued and TLS negotiation starts.

I hope much this would be fixed in next minor release of emacs.

Thanks!


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[-- Attachment #2: pop3.el-stls-order.patch --]
[-- Type: text/x-patch, Size: 1151 bytes --]

--- pop3.el.orig	2010-04-04 01:26:09.000000000 +0300
+++ pop3.el	2010-11-19 00:21:53.106967116 +0200
@@ -261,12 +261,6 @@
 		  (setq port 110))
 	      (let ((process (starttls-open-stream "POP" (current-buffer)
 						   mailhost (or port 110))))
-		(pop3-send-command process "STLS")
-		(let ((response (pop3-read-response process t)))
-		  (if (and response (string-match "+OK" response))
-		      (starttls-negotiate process)
-		    (pop3-quit process)
-		    (error "POP server doesn't support starttls")))
 		process))
 	     (t 
 	      (open-network-stream "POP" (current-buffer) mailhost port))))
@@ -274,6 +268,13 @@
 	(setq pop3-timestamp
 	      (substring response (or (string-match "<" response) 0)
 			 (+ 1 (or (string-match ">" response) -1)))))
+      (when (eq pop3-stream-type 'starttls)
+        (pop3-send-command process "STLS")
+        (let ((response (pop3-read-response process t)))
+          (if (and response (string-match "+OK" response))
+              (starttls-negotiate process)
+            (pop3-quit process)
+            (error "POP server doesn't support starttls"))))
       process)))
 
 ;; Support functions

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-- 
Citius Altius Fortius

bug#7438: 23.2; [PATCH] lisp/gnus/pop3.el fix STLS command ordering

[Chong Yidong]

Yuri Karaban <tech@askold.net> writes:

> Starttls (STLS) is not working with pop3.
>
> There is a bug in current implementation.
>
> Current implementation sends STLS just after opening connection.
>
> As result connection hangs (pop3.el tries to read a greeting message
> after STLS, but all POP3 servers I tried does not send anything after
> successful negotiation). On other hand, ignoring server greeting leads
> to mistreating server greeting (+OK <timestamp>) as successful response
> to STLS command. In this case negotiation starts too early (before
> reading real response to STLS).
>
> I've attached a patch which fixes the problem. The server greeting got
> read first (as with plain POP3) and only after receiving greeting STLS
> issued and TLS negotiation starts.
>
> I hope much this would be fixed in next minor release of emacs.

Looks reasonable.  I've checked your patch into the emacs-23 branch.
Thanks.