src/src/spf.c

   1 /* $Cambridge: exim/src/src/spf.c,v 1.6 2005/06/27 15:28:45 tom Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* Experimental SPF support.
   8    Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004
   9    License: GPL */
  10
  11 /* Code for calling spf checks via libspf-alt. Called from acl.c. */
  12
  13 #include "exim.h"
  14 #ifdef EXPERIMENTAL_SPF
  15
  16 /* must be kept in numeric order */
  17 static spf_result_id spf_result_id_list[] = {
  18   { US"invalid", 0},
  19   { US"neutral", 1 },
  20   { US"pass", 2 },
  21   { US"fail", 3 },
  22   { US"softfail", 4 },
  23   { US"none", 5 },
  24   { US"err_temp", 6 },
  25   { US"err_perm", 7 }
  26 };
  27
  28 SPF_server_t    *spf_server = NULL;
  29 SPF_request_t   *spf_request = NULL;
  30 SPF_response_t  *spf_response = NULL;
  31 SPF_response_t  *spf_response_2mx = NULL;
  32
  33 /* spf_init sets up a context that can be re-used for several
  34    messages on the same SMTP connection (that come from the
  35    same host with the same HELO string) */
  36
  37 int spf_init(uschar *spf_helo_domain, uschar *spf_remote_addr) {
  38
  39   spf_server = SPF_server_new(SPF_DNS_CACHE, 0);
  40
  41   if ( spf_server == NULL ) {
  42     debug_printf("spf: SPF_server_new() failed.\n");
  43     return 0;
  44   }
  45
  46   spf_request = SPF_request_new(spf_server);
  47
  48   if (SPF_request_set_ipv4_str(spf_request, spf_remote_addr)) {
  49     debug_printf("spf: SPF_request_set_ipv4_str() failed.\n");
  50     spf_server = NULL;
  51     spf_request = NULL;
  52     return 0;
  53   }
  54
  55   if (SPF_request_set_helo_dom(spf_request, spf_helo_domain)) {
  56     debug_printf("spf: SPF_set_helo_dom() failed.\n");
  57     spf_server = NULL;
  58     spf_request = NULL;
  59     return 0;
  60   }
  61
  62   return 1;
  63 }
  64
  65
  66 /* spf_process adds the envelope sender address to the existing
  67    context (if any), retrieves the result, sets up expansion
  68    strings and evaluates the condition outcome. */
  69
  70 int spf_process(uschar **listptr, uschar *spf_envelope_sender) {
  71   int sep = 0;
  72   uschar *list = *listptr;
  73   uschar *spf_result_id;
  74   uschar spf_result_id_buffer[128];
  75   int rc = SPF_RESULT_PERMERROR;
  76
  77   if (!(spf_server && spf_request)) {
  78     /* no global context, assume temp error and skip to evaluation */
  79     rc = SPF_RESULT_PERMERROR;
  80     goto SPF_EVALUATE;
  81   };
  82
  83   if (SPF_request_set_env_from(spf_request, spf_envelope_sender)) {
  84     /* Invalid sender address. This should be a real rare occurence */
  85     rc = SPF_RESULT_PERMERROR;
  86     goto SPF_EVALUATE;
  87   }
  88
  89   /* get SPF result */
  90   SPF_request_query_mailfrom(spf_request, &spf_response);
  91
  92   /* set up expansion items */
  93   spf_header_comment     = (uschar *)SPF_response_get_header_comment(spf_response);
  94   spf_received           = (uschar *)SPF_response_get_received_spf(spf_response);
  95   spf_result             = (uschar *)SPF_strresult(SPF_response_result(spf_response));
  96   spf_smtp_comment       = (uschar *)SPF_response_get_smtp_comment(spf_response);
  97
  98   rc = SPF_response_result(spf_response);
  99
 100   /* We got a result. Now see if we should return OK or FAIL for it */
 101   SPF_EVALUATE:
 102   debug_printf("SPF result is %s (%d)\n", SPF_strresult(rc), rc);
 103   while ((spf_result_id = string_nextinlist(&list, &sep,
 104                                      spf_result_id_buffer,
 105                                      sizeof(spf_result_id_buffer))) != NULL) {
 106     int negate = 0;
 107     int result = 0;
 108
 109     /* Check for negation */
 110     if (spf_result_id[0] == '!') {
 111       negate = 1;
 112       spf_result_id++;
 113     };
 114
 115     /* Check the result identifier */
 116     result = Ustrcmp(spf_result_id, spf_result_id_list[rc].name);
 117     if (!negate && result==0) return OK;
 118     if (negate && result!=0) return OK;
 119   };
 120
 121   /* no match */
 122   return FAIL;
 123 }
 124
 125 #endif