src/src/spf.c

   1 /* $Cambridge: exim/src/src/spf.c,v 1.3 2005/02/17 11:58:26 ph10 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 /* #include "spf.h" */
  17
  18 SPF_config_t        spfcid = NULL;
  19 SPF_dns_config_t    spfdcid_resolv = NULL;
  20 SPF_dns_config_t    spfdcid = NULL;
  21
  22
  23 /* spf_init sets up a context that can be re-used for several
  24    messages on the same SMTP connection (that come from the
  25    same host with the same HELO string) */
  26
  27 int spf_init(uschar *spf_helo_domain, uschar *spf_remote_addr) {
  28   uschar *p;
  29
  30   /* paranoia */
  31   spfcid = NULL;
  32   spfdcid_resolv = NULL;
  33   spfdcid = NULL;
  34
  35   spfcid = SPF_create_config();
  36   if ( spfcid == NULL ) {
  37     debug_printf("spf: SPF_create_config() failed.\n");
  38           return 0;
  39   }
  40
  41   /* set up resolver */
  42   spfdcid_resolv = SPF_dns_create_config_resolv(NULL, 0);
  43   spfdcid = SPF_dns_create_config_cache(spfdcid_resolv, 8, 0);
  44
  45   if (spfdcid == NULL) {
  46     debug_printf("spf: SPF_dns_create_config_cache() failed.\n");
  47     spfcid = NULL;
  48     spfdcid_resolv = NULL;
  49           return 0;
  50   }
  51
  52   if (SPF_set_ip_str(spfcid, spf_remote_addr)) {
  53     debug_printf("spf: SPF_set_ip_str() failed.\n");
  54     spfcid = NULL;
  55     spfdcid_resolv = NULL;
  56           return 0;
  57   }
  58
  59   if (SPF_set_helo_dom(spfcid, spf_helo_domain)) {
  60     debug_printf("spf: SPF_set_helo_dom() failed.\n");
  61     spfcid = NULL;
  62     spfdcid_resolv = NULL;
  63           return 0;
  64   }
  65
  66   return 1;
  67 }
  68
  69
  70 /* spf_process adds the envelope sender address to the existing
  71    context (if any), retrieves the result, sets up expansion
  72    strings and evaluates the condition outcome. */
  73
  74 int spf_process(uschar **listptr, uschar *spf_envelope_sender) {
  75   int sep = 0;
  76   uschar *list = *listptr;
  77   uschar *spf_result_id;
  78   uschar spf_result_id_buffer[128];
  79   SPF_output_t spf_output;
  80   int rc = SPF_RESULT_ERROR;
  81
  82   if (!(spfcid && spfdcid)) {
  83     /* no global context, assume temp error and skip to evaluation */
  84     rc = SPF_RESULT_ERROR;
  85     goto SPF_EVALUATE;
  86   };
  87
  88   if (SPF_set_env_from(spfcid, spf_envelope_sender)) {
  89     /* Invalid sender address. This should be a real rare occurence */
  90     rc = SPF_RESULT_ERROR;
  91     goto SPF_EVALUATE;
  92   }
  93
  94   /* get SPF result */
  95   spf_output = SPF_result(spfcid, spfdcid);
  96
  97   /* set up expansion items */
  98   spf_header_comment     = spf_output.header_comment ? (uschar *)spf_output.header_comment : NULL;
  99   spf_received           = spf_output.received_spf ? (uschar *)spf_output.received_spf : NULL;
 100   spf_result             = (uschar *)SPF_strresult(spf_output.result);
 101   spf_smtp_comment       = spf_output.smtp_comment ? (uschar *)spf_output.smtp_comment : NULL;
 102
 103   rc = spf_output.result;
 104
 105   /* We got a result. Now see if we should return OK or FAIL for it */
 106   SPF_EVALUATE:
 107   debug_printf("SPF result is %s (%d)\n", SPF_strresult(rc), rc);
 108   while ((spf_result_id = string_nextinlist(&list, &sep,
 109                                      spf_result_id_buffer,
 110                                      sizeof(spf_result_id_buffer))) != NULL) {
 111     int negate = 0;
 112     int result = 0;
 113
 114     /* Check for negation */
 115     if (spf_result_id[0] == '!') {
 116       negate = 1;
 117       spf_result_id++;
 118     };
 119
 120     /* Check the result identifier */
 121     result = Ustrcmp(spf_result_id, spf_result_id_list[rc].name);
 122     if (!negate && result==0) return OK;
 123     if (negate && result!=0) return OK;
 124   };
 125
 126   /* no match */
 127   return FAIL;
 128 }
 129
 130 #endif
 131