diff options
Diffstat (limited to 'src/local/bounce_workaround.c')
| -rw-r--r-- | src/local/bounce_workaround.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/src/local/bounce_workaround.c b/src/local/bounce_workaround.c new file mode 100644 index 0000000..7fe4aaa --- /dev/null +++ b/src/local/bounce_workaround.c @@ -0,0 +1,159 @@ +/*++ +/* NAME +/* bounce_workaround 3 +/* SUMMARY +/* Send non-delivery notification with sender override +/* SYNOPSIS +/* #include "local.h" +/* +/* int bounce_workaround(state) +/* LOCAL_STATE state; +/* DESCRIPTION +/* This module works around a limitation in the bounce daemon +/* protocol, namely, the assumption that the envelope sender +/* address in a queue file is the delivery status notification +/* address for all recipients in that queue file. The assumption +/* is not valid when the local(8) delivery agent overrides the +/* envelope sender address by an owner- alias, for one or more +/* recipients in the queue file. +/* +/* Sender address override is a problem only when delivering +/* to command or file, or when breaking a Delivered-To loop. +/* The local(8) delivery agent saves normal recipients to a +/* new queue file, together with the replacement envelope +/* sender address; delivery then proceeds from that new queue +/* file, and no workaround is needed. +/* +/* The workaround sends one non-delivery notification for each +/* failed delivery that has a replacement sender address. The +/* notifications are not aggregated, unlike notifications to +/* non-replaced sender addresses. In practice, a local alias +/* rarely has more than one file or command destination (if +/* only because soft error handling is problematic). +/* +/* Arguments: +/* .IP state +/* The attributes that specify the message, recipient and more. +/* Attributes describing alias, include or forward expansion. +/* A table with the results from expanding aliases or lists. +/* A table with delivered-to: addresses taken from the message. +/* The non-delivery status must be either 4.X.X or 5.X.X. +/* DIAGNOSTICS +/* Fatal errors: out of memory. The result is non-zero when +/* the operation should be tried again. Warnings: malformed +/* address. +/* BUGS +/* The proper fix is to record in the bounce logfile an error +/* return address for each individual recipient. This would +/* eliminate the need for VERP-specific bounce protocol code, +/* and would move complexity from the bounce client side to +/* the bounce server side where it more likely belongs. +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this +/* software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/*--*/ + +/* System library. */ + +#include <sys_defs.h> +#include <strings.h> + +/* Utility library. */ + +#include <msg.h> +#include <mymalloc.h> +#include <vstring.h> +#include <split_at.h> + +/* Global library. */ + +#include <mail_params.h> +#include <strip_addr.h> +#include <stringops.h> +#include <bounce.h> +#include <defer.h> +#include <split_addr.h> +#include <canon_addr.h> + +/* Application-specific. */ + +#include "local.h" + +int bounce_workaround(LOCAL_STATE state) +{ + const char *myname = "bounce_workaround"; + VSTRING *canon_owner = 0; + int rcpt_stat; + + /* + * Look up the substitute sender address. + */ + if (var_ownreq_special) { + char *stripped_recipient; + char *owner_alias; + const char *owner_expansion; + +#define FIND_OWNER(lhs, rhs, addr) { \ + lhs = concatenate("owner-", addr, (char *) 0); \ + (void) split_at_right(lhs, '@'); \ + rhs = maps_find(alias_maps, lhs, DICT_FLAG_NONE); \ + } + + FIND_OWNER(owner_alias, owner_expansion, state.msg_attr.rcpt.address); + if (alias_maps->error == 0 && owner_expansion == 0 + && (stripped_recipient = strip_addr(state.msg_attr.rcpt.address, + (char **) 0, + var_rcpt_delim)) != 0) { + myfree(owner_alias); + FIND_OWNER(owner_alias, owner_expansion, stripped_recipient); + myfree(stripped_recipient); + } + if (alias_maps->error == 0 && owner_expansion != 0) { + canon_owner = canon_addr_internal(vstring_alloc(10), + var_exp_own_alias ? + owner_expansion : owner_alias); + SET_OWNER_ATTR(state.msg_attr, STR(canon_owner), state.level); + } + myfree(owner_alias); + if (alias_maps->error != 0) { + /* At this point, canon_owner == 0. */ + dsb_simple(state.msg_attr.why, "4.3.0", + "alias database unavailable"); + return (defer_append(BOUNCE_FLAGS(state.request), + BOUNCE_ATTR(state.msg_attr))); + } + } + + /* + * Send a delivery status notification with a single recipient to the + * substitute sender address, before completion of the delivery request. + */ + if (canon_owner) { + rcpt_stat = + (STR(state.msg_attr.why->status)[0] == '4' ? + defer_one : bounce_one) + (BOUNCE_FLAGS(state.request), + BOUNCE_ONE_ATTR(state.msg_attr)); + vstring_free(canon_owner); + } + + /* + * Send a regular delivery status notification, after completion of the + * delivery request. + */ + else { + rcpt_stat = + (STR(state.msg_attr.why->status)[0] == '4' ? + defer_append : bounce_append) + (BOUNCE_FLAGS(state.request), + BOUNCE_ATTR(state.msg_attr)); + } + return (rcpt_stat); +} |