1 /* $NetBSD: bounce_workaround.c,v 1.2 2017/02/14 01:16:45 christos Exp $ */ 2 3 /*++ 4 /* NAME 5 /* bounce_workaround 3 6 /* SUMMARY 7 /* Send non-delivery notification with sender override 8 /* SYNOPSIS 9 /* #include "local.h" 10 /* 11 /* int bounce_workaround(state) 12 /* LOCAL_STATE state; 13 /* DESCRIPTION 14 /* This module works around a limitation in the bounce daemon 15 /* protocol, namely, the assumption that the envelope sender 16 /* address in a queue file is the delivery status notification 17 /* address for all recipients in that queue file. The assumption 18 /* is not valid when the local(8) delivery agent overrides the 19 /* envelope sender address by an owner- alias, for one or more 20 /* recipients in the queue file. 21 /* 22 /* Sender address override is a problem only when delivering 23 /* to command or file, or when breaking a Delivered-To loop. 24 /* The local(8) delivery agent saves normal recipients to a 25 /* new queue file, together with the replacement envelope 26 /* sender address; delivery then proceeds from that new queue 27 /* file, and no workaround is needed. 28 /* 29 /* The workaround sends one non-delivery notification for each 30 /* failed delivery that has a replacement sender address. The 31 /* notifications are not aggregated, unlike notifications to 32 /* non-replaced sender addresses. In practice, a local alias 33 /* rarely has more than one file or command destination (if 34 /* only because soft error handling is problematic). 35 /* 36 /* Arguments: 37 /* .IP state 38 /* The attributes that specify the message, recipient and more. 39 /* Attributes describing alias, include or forward expansion. 40 /* A table with the results from expanding aliases or lists. 41 /* A table with delivered-to: addresses taken from the message. 42 /* The non-delivery status must be either 4.X.X or 5.X.X. 43 /* DIAGNOSTICS 44 /* Fatal errors: out of memory. The result is non-zero when 45 /* the operation should be tried again. Warnings: malformed 46 /* address. 47 /* BUGS 48 /* The proper fix is to record in the bounce logfile an error 49 /* return address for each individual recipient. This would 50 /* eliminate the need for VERP-specific bounce protocol code, 51 /* and would move complexity from the bounce client side to 52 /* the bounce server side where it more likely belongs. 53 /* LICENSE 54 /* .ad 55 /* .fi 56 /* The Secure Mailer license must be distributed with this 57 /* software. 58 /* AUTHOR(S) 59 /* Wietse Venema 60 /* IBM T.J. Watson Research 61 /* P.O. Box 704 62 /* Yorktown Heights, NY 10598, USA 63 /*--*/ 64 65 /* System library. */ 66 67 #include <sys_defs.h> 68 #include <strings.h> 69 70 /* Utility library. */ 71 72 #include <msg.h> 73 #include <mymalloc.h> 74 #include <vstring.h> 75 #include <split_at.h> 76 77 /* Global library. */ 78 79 #include <mail_params.h> 80 #include <strip_addr.h> 81 #include <stringops.h> 82 #include <bounce.h> 83 #include <defer.h> 84 #include <split_addr.h> 85 #include <canon_addr.h> 86 87 /* Application-specific. */ 88 89 #include "local.h" 90 91 int bounce_workaround(LOCAL_STATE state) 92 { 93 const char *myname = "bounce_workaround"; 94 VSTRING *canon_owner = 0; 95 int rcpt_stat; 96 97 /* 98 * Look up the substitute sender address. 99 */ 100 if (var_ownreq_special) { 101 char *stripped_recipient; 102 char *owner_alias; 103 const char *owner_expansion; 104 105 #define FIND_OWNER(lhs, rhs, addr) { \ 106 lhs = concatenate("owner-", addr, (char *) 0); \ 107 (void) split_at_right(lhs, '@'); \ 108 rhs = maps_find(alias_maps, lhs, DICT_FLAG_NONE); \ 109 } 110 111 FIND_OWNER(owner_alias, owner_expansion, state.msg_attr.rcpt.address); 112 if (alias_maps->error == 0 && owner_expansion == 0 113 && (stripped_recipient = strip_addr(state.msg_attr.rcpt.address, 114 (char **) 0, 115 var_rcpt_delim)) != 0) { 116 myfree(owner_alias); 117 FIND_OWNER(owner_alias, owner_expansion, stripped_recipient); 118 myfree(stripped_recipient); 119 } 120 if (alias_maps->error == 0 && owner_expansion != 0) { 121 canon_owner = canon_addr_internal(vstring_alloc(10), 122 var_exp_own_alias ? 123 owner_expansion : owner_alias); 124 SET_OWNER_ATTR(state.msg_attr, STR(canon_owner), state.level); 125 } 126 myfree(owner_alias); 127 if (alias_maps->error != 0) { 128 /* At this point, canon_owner == 0. */ 129 dsb_simple(state.msg_attr.why, "4.3.0", 130 "alias database unavailable"); 131 return (defer_append(BOUNCE_FLAGS(state.request), 132 BOUNCE_ATTR(state.msg_attr))); 133 } 134 } 135 136 /* 137 * Send a delivery status notification with a single recipient to the 138 * substitute sender address, before completion of the delivery request. 139 */ 140 if (canon_owner) { 141 rcpt_stat = 142 (STR(state.msg_attr.why->status)[0] == '4' ? 143 defer_one : bounce_one) 144 (BOUNCE_FLAGS(state.request), 145 BOUNCE_ONE_ATTR(state.msg_attr)); 146 vstring_free(canon_owner); 147 } 148 149 /* 150 * Send a regular delivery status notification, after completion of the 151 * delivery request. 152 */ 153 else { 154 rcpt_stat = 155 (STR(state.msg_attr.why->status)[0] == '4' ? 156 defer_append : bounce_append) 157 (BOUNCE_FLAGS(state.request), 158 BOUNCE_ATTR(state.msg_attr)); 159 } 160 return (rcpt_stat); 161 } 162