From: Oles' Hnatkevych (no email)
Date: Wed Jan 02 2002 - 04:29:54 EST
Hello,
My mail is intended mainly for postfix developers/hackers.
There's a simple way to make separate message size limit
depending on the sender/recipient address. I've made some
changes to the smtpd daemon sources, and it works for me.
However I do not know are they correct or not, and
if it is a good idea, I believe many postfix users would
want to make use of this feature when it will be included
in the main source tree properly and correctly. And I would
like to know your comments about the feature and the way
I've implemented it.
Looking a bit through the sources I found that the best
way to do it is by implementing new rule to the access
tables, so with "OK" and "RELAY" (which is the same to smtpd)
we have a new records with "SIZE=xxx", where xxx is the
size in kylobytes. The changes to the smtpd sources are:
File smtpd.h contains a definition of the record SMTPD_STATE,
and idea is to use a new field "state->var_message_limit"
in the record instead of the global "var_message_limit".
It defaults to the global variable, and is initialized
by smtpd_state_init() function, and is updated when
the search is made in function check_table_result() in
smtpd_check.c.
However there are some caveats about that. The RCPT command
is processed after MAIL command. So the SIZE=xxx for recipient
address will override the size for the sender address. More,
to use the restriction on recipient addresses,
"smtpd_delay_reject = no" has to be present in main.cf.
... are there any other MTA's that can make mail size restrictions
depending on sender/recipient?
The summary patch follows:
----------------------//-------------------------
*** smtpd.c Thu Nov 15 16:52:50 2001
--- /home/gnut/posfix-patch/smtpd.c Wed Jan 2 11:19:52 2002
***************
*** 439,447 ****
state->protocol = "ESMTP";
smtpd_chat_reply(state, "250-%s", var_myhostname);
smtpd_chat_reply(state, "250-PIPELINING");
! if (var_message_limit)
smtpd_chat_reply(state, "250-SIZE %lu",
! (unsigned long) var_message_limit); /* XXX */
else
smtpd_chat_reply(state, "250-SIZE");
smtpd_chat_reply(state, "250-ETRN");
--- 439,447 ----
state->protocol = "ESMTP";
smtpd_chat_reply(state, "250-%s", var_myhostname);
smtpd_chat_reply(state, "250-PIPELINING");
! if (state->var_message_limit)
smtpd_chat_reply(state, "250-SIZE %lu",
! (unsigned long) state->var_message_limit); /* XXX */
else
smtpd_chat_reply(state, "250-SIZE");
smtpd_chat_reply(state, "250-ETRN");
***************
*** 791,796 ****
--- 791,802 ----
return (-1);
}
}
+ if ((SMTPD_STAND_ALONE(state) || var_smtpd_delay_reject == 0)
+ && (err = smtpd_check_size(state, state->msg_size)) != 0) {
+ smtpd_chat_reply(state, "%s", err);
+ return (-1);
+ }
+
/*
* Store the recipient. Remember the first one.
*** smtpd.h Wed Jan 2 11:20:11 2002
--- /home/gnut/posfix-patch/smtpd.h Wed Jan 2 11:19:52 2002
***************
*** 66,71 ****
--- 66,72 ----
char *where;
int recursion;
off_t msg_size;
+ off_t var_message_limit;
int junk_cmds;
#ifdef USE_SASL_AUTH
char *sasl_mechanism_list;
*** smtpd_check.c Tue Jul 31 17:26:41 2001
--- /home/gnut/posfix-patch/smtpd_check.c Wed Jan 2 11:19:52 2002
***************
*** 1290,1295 ****
--- 1290,1306 ----
if (strcasecmp(value, "OK") == 0 || strcasecmp(value, "RELAY") == 0)
return (SMTPD_CHECK_OK);
+ if (strncasecmp(value, "SIZE=",5) == 0) {
+ char * value_size = mystrdup(value+5);
+ if ((state->var_message_limit = off_cvt_string(value + 5)) < 0) {
+ state->var_message_limit = var_message_limit;
+ } else {
+ state->var_message_limit *= 1024;
+ }
+ return (SMTPD_CHECK_OK);
+ }
+
/*
* Unfortunately, maps must be declared ahead of time so they can be
* opened before we go to jail. We could insist that the RHS can only
***************
*** 2161,2167 ****
*/
#define BLOCKS(x) ((x) / fsbuf.block_size)
! if (var_message_limit > 0 && size > var_message_limit) {
(void) smtpd_check_reject(state, MAIL_ERROR_POLICY,
"552 Message size exceeds fixed limit");
return (STR(error_text));
--- 2172,2178 ----
*/
#define BLOCKS(x) ((x) / fsbuf.block_size)
! if (state->var_message_limit > 0 && size > state->var_message_limit) {
(void) smtpd_check_reject(state, MAIL_ERROR_POLICY,
"552 Message size exceeds fixed limit");
return (STR(error_text));
*** smtpd_state.c Sat Nov 25 03:03:09 2000
--- /home/gnut/posfix-patch/smtpd_state.c Wed Jan 2 11:19:52 2002
***************
*** 90,95 ****
--- 90,96 ----
state->where = SMTPD_AFTER_CONNECT;
state->recursion = 0;
state->msg_size = 0;
+ state->var_message_limit = var_message_limit;
state->junk_cmds = 0;
#ifdef USE_SASL_AUTH
----------------------//-------------------------
With best wishes, Oles' Hnatkevych, http://gnut.kiev.ua,
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