1/* $NetBSD: postscreen_expand.c,v 1.2 2017/02/14 01:16:47 christos Exp $ */ 2 3/*++ 4/* NAME 5/* postscreen_expand 3 6/* SUMMARY 7/* SMTP server macro expansion 8/* SYNOPSIS 9/* #include <postscreen.h> 10/* 11/* void psc_expand_init() 12/* 13/* VSTRING *psc_expand_filter; 14/* 15/* const char *psc_expand_lookup(name, unused_mode, context) 16/* const char *name; 17/* int unused_mode; 18/* char *context; 19/* DESCRIPTION 20/* This module expands session-related macros. 21/* 22/* psc_expand_init() performs one-time initialization 23/* of the psc_expand_filter buffer. 24/* 25/* The psc_expand_filter buffer contains the characters 26/* that are allowed in macro expansion, as specified with the 27/* psc_expand_filter configuration parameter. 28/* 29/* psc_expand_lookup() returns the value of the named 30/* macro or a null pointer. 31/* 32/* Arguments: 33/* .IP name 34/* Macro name. 35/* .IP context 36/* Call-back context (a PSC_STATE pointer). 37/* DIAGNOSTICS 38/* Panic: interface violations. Fatal errors: out of memory. 39/* internal protocol errors. postscreen_expand() returns the 40/* binary OR of MAC_PARSE_ERROR (syntax error) and MAC_PARSE_UNDEF 41/* (undefined macro name). 42/* LICENSE 43/* .ad 44/* .fi 45/* The Secure Mailer license must be distributed with this software. 46/* AUTHOR(S) 47/* Wietse Venema 48/* IBM T.J. Watson Research 49/* P.O. Box 704 50/* Yorktown Heights, NY 10598, USA 51/*--*/ 52 53/* System library. */ 54 55#include <sys_defs.h> 56#include <time.h> 57 58/* Utility library. */ 59 60#include <msg.h> 61#include <vstring.h> 62#include <stringops.h> 63 64/* Global library. */ 65 66#include <mail_params.h> 67#include <mail_proto.h> 68 69/* Application-specific. */ 70 71#include <postscreen.h> 72 73 /* 74 * Pre-parsed expansion filter. 75 */ 76VSTRING *psc_expand_filter; 77 78/* psc_expand_init - initialize once during process lifetime */ 79 80void psc_expand_init(void) 81{ 82 83 /* 84 * Expand the expansion filter :-) 85 */ 86 psc_expand_filter = vstring_alloc(10); 87 unescape(psc_expand_filter, var_psc_exp_filter); 88} 89 90/* psc_expand_lookup - generic SMTP attribute $name expansion */ 91 92const char *psc_expand_lookup(const char *name, int unused_mode, 93 void *context) 94{ 95 PSC_STATE *state = (PSC_STATE *) context; 96 time_t now; 97 struct tm *lt; 98 99 if (state->expand_buf == 0) 100 state->expand_buf = vstring_alloc(10); 101 102 if (msg_verbose > 1) 103 msg_info("psc_expand_lookup: ${%s}", name); 104 105#define STREQ(x,y) (*(x) == *(y) && strcmp((x), (y)) == 0) 106#define STREQN(x,y,n) (*(x) == *(y) && strncmp((x), (y), (n)) == 0) 107#define CONST_LEN(x) (sizeof(x) - 1) 108 109 /* 110 * Don't query main.cf parameters, as the result of expansion could 111 * reveal system-internal information in server replies. 112 * 113 * XXX: This said, multiple servers may be behind a single client-visible 114 * name or IP address, and each may generate its own logs. Therefore, it 115 * may be useful to expose the replying MTA id (myhostname) in the 116 * contact footer, to identify the right logs. So while we don't expose 117 * the raw configuration dictionary, we do expose "$myhostname" as 118 * expanded in var_myhostname. 119 * 120 * Return NULL only for non-existent names. 121 */ 122 if (STREQ(name, MAIL_ATTR_SERVER_NAME)) { 123 return (var_myhostname); 124 } else if (STREQ(name, MAIL_ATTR_ACT_CLIENT_ADDR)) { 125 return (state->smtp_client_addr); 126 } else if (STREQ(name, MAIL_ATTR_ACT_CLIENT_PORT)) { 127 return (state->smtp_client_port); 128 } if (STREQ(name, MAIL_ATTR_LOCALTIME)) { 129 if (time(&now) == (time_t) -1) 130 msg_fatal("time lookup failed: %m"); 131 lt = localtime(&now); 132 VSTRING_RESET(state->expand_buf); 133 do { 134 VSTRING_SPACE(state->expand_buf, 100); 135 } while (strftime(STR(state->expand_buf), 136 vstring_avail(state->expand_buf), 137 "%b %d %H:%M:%S", lt) == 0); 138 return (STR(state->expand_buf)); 139 } else { 140 msg_warn("unknown macro name \"%s\" in expansion request", name); 141 return (0); 142 } 143} 144