#------------------------------------------------------------------------------
# Who:
#   Richard Nelson <cowboy@{cavein,debian}.org>
# What:
#	1) New macro ${client_helo} containing the EHLO/HELO text (or null)
#	2) New ruleset check_helo called after the EHLO/HELO and before the
#		milter callout.  This ruleset invocation and handling are modeled
#		after the existing check_* rulesets
# Why:
#	0) $s is transient, and not set until MAIL FROM: is seen - I want the
#		ability to check the EHLO/HELO string elsewere (like check_vrfy).
#		${client_helo} is set upon seeing the EHLO/HELO command and 
#		remains valid forever.
#	1) There is an IBM internal system check routine for AIX and Linux that 
#		I'm thinking will soon be a requirement to pass its audit...  Like
#		all such tools, it is limited - it requires that vrfy,expn are
#		disabled...  well, I don't do that... if you can relay through the
#		box, then you can query it.  If you can't relay, you get 5.7.1 !
#		using the new macro - I can specifically deny the scanner - even
#		though other traffic is unaffected.
#	2) It can provide the same function as -DPICKY_HELO_CHECK, dynamically
#		by making those checks in the new check_helo ruleset - as outlined
#		below (NOT RECOMMENDED)
#	3) It can be passed to the milters, if they choose (like mimedefang)
#		to apparently not support the helo callout
#	4) I was bored stiff being in the bowels of a COBOL compiler and
#		needed a sanity break :)
# Design questions:
# Testing:
#	1) Running on three boxes, two of which make use of the macro and
#		ruleset to block.  The new function works great - and no ill
#		affects seen on any of the boxes.
# Documentation:
#	See below for the new macro and ruleset
# TODO:
#	add to milter macro specifications
# Changes:
#	1) deliver.c -- remove client_helo from the envelope like all the
#		other client_* macros
#	2) srvrsmtp.c
#		A) A new boolean variable indicating that the helo string is valid
#			gothelo is not sufficient here... the new scope is very small...
#		B) A new character pointer holding the helo string address
#		C) After obtaining a valid helo string, or accepting an invalid
#			one, create a copy of the string for permanence
#		D) Update the client_helo macro variable with the helo string
#------------------------------------------------------------------------------
#5.2.  D -- Define Macro
# ...
# ${client_helo}
#           The string specified by the SMTP client on the EHLO/HELO
#           command, or null if no EHLO/HELO was seen.  Defined in the
#           SMTP server only.  Unlike the $s macro, which is transient
#           and not available in all rulesets, the {client_helo} macro
#           is available to all rulesets after the EHLO/HELO greeting.
# ...
#------------------------------------------------------------------------------
#5.1.4.?.  check_helo
#
#                 The check_helo ruleset is passed the address  
#            or name parameter of the SMTP EHLO/HELO command.  It can
#            accept or reject the address.  Note that rejecting mail
#            based upon this check is a violation of the standards!
#
#            One could impliment an improved -PICKY_HELO_CHECK test
#            here by checking the values of {client_name}, {client_addr},
#            against {client_helo} and {daemon_addr}.
#------------------------------------------------------------------------------
diff -c 'deliver.orig' 'deliver.c'
Index: ./deliver.orig
Prereq:  8.986
*** ./sendmail-8.13.4/sendmail/deliver.c	Tue Aug 10 17:50:11 2004
--- ./deliver.c	Tue Aug 10 17:44:04 2004
***************
*** 1363,1368 ****
--- 1363,1369 ----
  		macdefine(&e->e_macro, A_PERM, macid("{client_addr}"), "");
  		macdefine(&e->e_macro, A_PERM, macid("{client_port}"), "");
  		macdefine(&e->e_macro, A_PERM, macid("{client_resolve}"), "");
+ 		macdefine(&e->e_macro, A_PERM, macid("{client_helo}"), "");
  	}
  
  	SM_TRY
diff -c 'srvrsmtp.orig' 'srvrsmtp.c'
Index: ./srvrsmtp.orig
Prereq:  8.906
*** ./sendmail-8.13.4/sendmail/srvrsmtp.c	Tue Aug 10 17:50:23 2004
--- ./srvrsmtp.c	Tue Aug 10 17:42:54 2004
***************
*** 444,449 ****
--- 444,451 ----
  	char *volatile protocol;	/* sending protocol */
  	char *volatile sendinghost;	/* sending hostname */
  	char *volatile peerhostname;	/* name of SMTP peer or "localhost" */
+ 	char *volatile helo_name;	/* client_helo string */
+ 	bool helo_accept = false;	/* helo/ehlo command accepted */
  	auto char *delimptr;
  	char *id;
  	volatile unsigned int n_badcmds = 0;	/* count of bad commands */
***************
*** 1976,1981 ****
--- 1978,1987 ----
  			{
  				q = "pleased to meet you";
  				sendinghost = sm_strdup_x(p);
+ 				helo_accept = true;
+ 				helo_name = sm_strdup_x(p);
+ 				macdefine(&e->e_macro, A_PERM, macid("{client_helo}"),
+ 					helo_name);
  			}
  			else if (!AllowBogusHELO)
  			{
***************
*** 1989,1994 ****
--- 1995,2004 ----
  			else
  			{
  				q = "accepting invalid domain name";
+ 				helo_accept = true;
+ 				helo_name = sm_strdup_x(p);
+ 				macdefine(&e->e_macro, A_PERM, macid("{client_helo}"),
+ 					helo_name);
  			}
  
  			if (gothelo)
***************
*** 1996,2001 ****
--- 2006,2028 ----
  				CLEAR_STATE(cmdbuf);
  			}
  
+ 			if (helo_accept) {
+ 				if (rscheck("check_helo", helo_name,
+ 						NULL, e, RSF_RMCOMM|RSF_COUNT, 3,
+ 						NULL, e->e_id) != EX_OK ||
+ 					Errors > 0)
+ 					sm_exc_raisenew_x(&EtypeQuickAbort, 1);
+ 
+ 				if (MaxMessageSize > 0 &&
+ 					(e->e_msgsize > MaxMessageSize ||
+ 					 e->e_msgsize < 0))
+ 					{
+ 						usrerr("552 5.2.3 Message size exceeds fixed maximum message size (%ld)",
+ 							MaxMessageSize);
+ 						sm_exc_raisenew_x(&EtypeQuickAbort, 1);
+ 					}
+ 				}
+ 
  #if MILTER
  			if (smtp.sm_milterlist && smtp.sm_milterize &&
  			    !bitset(EF_DISCARD, e->e_flags))