src/src/spf.c

   1 /* $Cambridge: exim/src/src/spf.c,v 1.4 2005/05/24 08:15:02 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 SPF_server_t    *spf_server = NULL;
  17 SPF_request_t   *spf_request = NULL;
  18 SPF_response_t  *spf_response = NULL;
  19 SPF_response_t  *spf_response_2mx = NULL;
  20
  21 /* spf_init sets up a context that can be re-used for several
  22    messages on the same SMTP connection (that come from the
  23    same host with the same HELO string) */
  24
  25 int spf_init(uschar *spf_helo_domain, uschar *spf_remote_addr) {
  26   uschar *p;
  27
  28   spf_server = SPF_server_new(SPF_DNS_CACHE, 1);
  29
  30   if ( spf_server == NULL ) {
  31     debug_printf("spf: SPF_server_new() failed.\n");
  32     return 0;
  33   }
  34
  35   spf_request = SPF_request_new(spf_server);
  36
  37   if (SPF_request_set_ipv4_str(spf_request, spf_remote_addr)) {
  38     debug_printf("spf: SPF_request_set_ipv4_str() failed.\n");
  39     spf_server = NULL;
  40     spf_request = NULL;
  41     return 0;
  42   }
  43
  44   if (SPF_request_set_helo_dom(spf_request, spf_helo_domain)) {
  45     debug_printf("spf: SPF_set_helo_dom() failed.\n");
  46     spf_server = NULL;
  47     spf_request = NULL;
  48     return 0;
  49   }
  50
  51   return 1;
  52 }
  53
  54
  55 /* spf_process adds the envelope sender address to the existing
  56    context (if any), retrieves the result, sets up expansion
  57    strings and evaluates the condition outcome. */
  58
  59 int spf_process(uschar **listptr, uschar *spf_envelope_sender) {
  60   int sep = 0;
  61   uschar *list = *listptr;
  62   uschar *spf_result_id;
  63   uschar spf_result_id_buffer[128];
  64   int rc = SPF_RESULT_PERMERROR;
  65
  66   if (!(spf_server && spf_request)) {
  67     /* no global context, assume temp error and skip to evaluation */
  68     rc = SPF_RESULT_PERMERROR;
  69     goto SPF_EVALUATE;
  70   };
  71
  72   if (SPF_request_set_env_from(spf_request, spf_envelope_sender)) {
  73     /* Invalid sender address. This should be a real rare occurence */
  74     rc = SPF_RESULT_PERMERROR;
  75     goto SPF_EVALUATE;
  76   }
  77
  78   /* get SPF result */
  79   SPF_request_query_mailfrom(spf_request, &spf_response);
  80
  81   /* set up expansion items */
  82   spf_header_comment     = (uschar *)SPF_response_get_header_comment(spf_response);
  83   spf_received           = (uschar *)SPF_response_get_received_spf(spf_response);
  84   spf_result             = (uschar *)SPF_strresult(SPF_response_result(spf_response));
  85   spf_smtp_comment       = (uschar *)SPF_response_get_smtp_comment(spf_response);
  86
  87   rc = SPF_response_result(spf_response);
  88
  89   /* We got a result. Now see if we should return OK or FAIL for it */
  90   SPF_EVALUATE:
  91   debug_printf("SPF result is %s (%d)\n", SPF_strresult(rc), rc);
  92   while ((spf_result_id = string_nextinlist(&list, &sep,
  93                                      spf_result_id_buffer,
  94                                      sizeof(spf_result_id_buffer))) != NULL) {
  95     int negate = 0;
  96     int result = 0;
  97
  98     /* Check for negation */
  99     if (spf_result_id[0] == '!') {
 100       negate = 1;
 101       spf_result_id++;
 102     };
 103
 104     /* Check the result identifier */
 105     result = Ustrcmp(spf_result_id, spf_result_id_list[rc].name);
 106     if (!negate && result==0) return OK;
 107     if (negate && result!=0) return OK;
 108   };
 109
 110   /* no match */
 111   return FAIL;
 112 }
 113
 114 #endif
 115