X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/53ef3d8498e76615b531f2f61604334e9884ba03..3c90bbcdc7cf73298156f7bcd5f5e750e7814e72:/src/src/spf.c

diff --git a/src/src/spf.c b/src/src/spf.c
index 7671551bc..48f26f315 100644
--- a/src/src/spf.c
+++ b/src/src/spf.c
@@ -72,6 +72,17 @@ int dns_rc;
 
 DEBUG(D_receive) debug_printf("SPF_dns_exim_lookup '%s'\n", domain);
 
+/* Shortcircuit SPF RR lookups by returning NO_DATA.  They were obsoleted by
+RFC 6686/7208 years ago. see bug #1294 */
+
+if (rr_type == T_SPF)
+  {
+  HDEBUG(D_host_lookup) debug_printf("faking NO_DATA for SPF RR(99) lookup\n");
+  srr.herrno = NO_DATA;
+  SPF_dns_rr_dup(&spfrr, &srr);
+  return spfrr;
+  }
+
 switch (dns_rc = dns_lookup(dnsa, US domain, rr_type, NULL))
   {
   case DNS_SUCCEED:	srr.herrno = NETDB_SUCCESS;	break;
@@ -80,7 +91,7 @@ switch (dns_rc = dns_lookup(dnsa, US domain, rr_type, NULL))
   case DNS_NODATA:	srr.herrno = NO_DATA;		break;
   case DNS_FAIL:
   default:		srr.herrno = NO_RECOVERY;	break;
-  } 
+  }
 
 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
      rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
@@ -152,7 +163,12 @@ for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
     srr.rr[found++] = (void *) s;
     }
 
-srr.num_rr = found;
+/* Did we filter out all TXT RRs? Return NO_DATA instead of SUCCESS with
+empty ANSWER section. */
+
+if (!(srr.num_rr = found))
+  srr.herrno = NO_DATA;
+
 /* spfrr->rr must have been malloc()d for this */
 SPF_dns_rr_dup(&spfrr, &srr);
 return spfrr;
@@ -202,6 +218,7 @@ spf_init(void)
 {
 SPF_dns_server_t * dc;
 int debug = 0;
+const uschar *s;
 
 DEBUG(D_receive) debug = 1;
 
@@ -224,11 +241,16 @@ if (!(spf_server = SPF_server_new_dns(dc, debug)))
   DEBUG(D_receive) debug_printf("spf: SPF_server_new() failed.\n");
   return FALSE;
   }
-  /* Quick hack to override the outdated explanation URL.
-  See https://www.mail-archive.com/mailop@mailop.org/msg08019.html */
-  SPF_server_set_explanation(spf_server, "Please%_see%_http://www.open-spf.org/Why?id=%{S}&ip=%{C}&receiver=%{R}", &spf_response);
-  if (SPF_response_errcode(spf_response) != SPF_E_SUCCESS)
-    log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", SPF_strerror(SPF_response_errcode(spf_response)));
+  /* Override the outdated explanation URL.
+  See https://www.mail-archive.com/mailop@mailop.org/msg08019.html
+  Used to work as "Please%_see%_http://www.open-spf.org/Why?id=%{S}&ip=%{C}&receiver=%{R}",
+  but is broken now (May 18th, 2020) */
+if (!(s = expand_string(spf_smtp_comment_template)))
+  log_write(0, LOG_MAIN|LOG_PANIC_DIE, "expansion of spf_smtp_comment_template failed");
+
+SPF_server_set_explanation(spf_server, CCS s, &spf_response);
+if (SPF_response_errcode(spf_response) != SPF_E_SUCCESS)
+  log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", SPF_strerror(SPF_response_errcode(spf_response)));
 
 return TRUE;
 }