X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/6372d4c990f39ba6ad84a91af0a3a61a63bd50a3..3510ce5f0447a13ee2a5e882cee2a9ce9d1280af:/src/src/dmarc.c

diff --git a/src/src/dmarc.c b/src/src/dmarc.c
index 956c16b4e..2e43f846d 100644
--- a/src/src/dmarc.c
+++ b/src/src/dmarc.c
@@ -1,8 +1,9 @@
 /*************************************************
 *     Exim - an Internet mail transport agent    *
 *************************************************/
-/* Experimental DMARC support.
+/* DMARC support.
    Copyright (c) Todd Lyons <tlyons@exim.org> 2012 - 2014
+   Copyright (c) The Exim Maintainers 2019
    License: GPL */
 
 /* Portions Copyright (c) 2012, 2013, The Trusted Domain Project;
@@ -11,7 +12,7 @@
 /* Code for calling dmarc checks via libopendmarc. Called from acl.c. */
 
 #include "exim.h"
-#ifdef EXPERIMENTAL_DMARC
+#ifdef SUPPORT_DMARC
 # if !defined SUPPORT_SPF
 #  error SPF must also be enabled for DMARC
 # elif defined DISABLE_DKIM
@@ -91,13 +92,13 @@ dmarc_status       = US"none";
 dmarc_abort        = FALSE;
 dmarc_pass_fail    = US"skipped";
 dmarc_used_domain  = US"";
-dmarc_has_been_checked = FALSE;
+f.dmarc_has_been_checked = FALSE;
 header_from_sender = NULL;
 spf_sender_domain  = NULL;
 spf_human_readable = NULL;
 
 /* ACLs have "control=dmarc_disable_verify" */
-if (dmarc_disable_verify == TRUE)
+if (f.dmarc_disable_verify == TRUE)
   return OK;
 
 (void) memset(&dmarc_ctx, '\0', sizeof dmarc_ctx);
@@ -109,15 +110,15 @@ if (libdm_status != DMARC_PARSE_OKAY)
 		       opendmarc_policy_status_to_str(libdm_status));
   dmarc_abort = TRUE;
   }
-if (!dmarc_tld_file)
+if (!dmarc_tld_file || !*dmarc_tld_file)
   {
   DEBUG(D_receive) debug_printf("DMARC: no dmarc_tld_file\n");
   dmarc_abort = TRUE;
   }
-else if (opendmarc_tld_read_file(dmarc_tld_file, NULL, NULL, NULL))
+else if (opendmarc_tld_read_file(CS dmarc_tld_file, NULL, NULL, NULL))
   {
-  log_write(0, LOG_MAIN|LOG_PANIC, "DMARC failure to load tld list %s: %d",
-		       dmarc_tld_file, errno);
+  log_write(0, LOG_MAIN|LOG_PANIC, "DMARC failure to load tld list '%s': %s",
+		       dmarc_tld_file, strerror(errno));
   dmarc_abort = TRUE;
   }
 if (!sender_host_address)
@@ -148,7 +149,7 @@ int
 dmarc_store_data(header_line *hdr)
 {
 /* No debug output because would change every test debug output */
-if (!dmarc_disable_verify)
+if (!f.dmarc_disable_verify)
   from_header = hdr;
 return OK;
 }
@@ -157,14 +158,13 @@ return OK;
 static void
 dmarc_send_forensic_report(u_char **ruf)
 {
-int   c;
 uschar *recipient, *save_sender;
 BOOL  send_status = FALSE;
 error_block *eblock = NULL;
 FILE *message_file = NULL;
 
 /* Earlier ACL does not have *required* control=dmarc_enable_forensic */
-if (!dmarc_enable_forensic)
+if (!f.dmarc_enable_forensic)
   return;
 
 if (  dmarc_policy == DMARC_POLICY_REJECT     && action == DMARC_RESULT_REJECT
@@ -178,15 +178,12 @@ if (  dmarc_policy == DMARC_POLICY_REJECT     && action == DMARC_RESULT_REJECT
     eblock = add_to_eblock(eblock, US"Sender IP Address", sender_host_address);
     eblock = add_to_eblock(eblock, US"Received Date", tod_stamp(tod_full));
     eblock = add_to_eblock(eblock, US"SPF Alignment",
-			   (sa==DMARC_POLICY_SPF_ALIGNMENT_PASS) ?US"yes":US"no");
+		     sa == DMARC_POLICY_SPF_ALIGNMENT_PASS ? US"yes" : US"no");
     eblock = add_to_eblock(eblock, US"DKIM Alignment",
-			   (da==DMARC_POLICY_DKIM_ALIGNMENT_PASS)?US"yes":US"no");
+		     da == DMARC_POLICY_DKIM_ALIGNMENT_PASS ? US"yes" : US"no");
     eblock = add_to_eblock(eblock, US"DMARC Results", dmarc_status_text);
-    /* Set a sane default envelope sender */
-    dsn_from = dmarc_forensic_sender ? dmarc_forensic_sender :
-	       dsn_from ? dsn_from :
-	       string_sprintf("do-not-reply@%s",primary_hostname);
-    for (c = 0; ruf[c]; c++)
+
+    for (int c = 0; ruf[c]; c++)
       {
       recipient = string_copylc(ruf[c]);
       if (Ustrncmp(recipient, "mailto:",7))
@@ -195,22 +192,37 @@ if (  dmarc_policy == DMARC_POLICY_REJECT     && action == DMARC_RESULT_REJECT
       recipient += 7;
       DEBUG(D_receive)
 	debug_printf("DMARC forensic report to %s%s\n", recipient,
-	     (host_checking || running_in_test_harness) ? " (not really)" : "");
-      if (host_checking || running_in_test_harness)
+	     (host_checking || f.running_in_test_harness) ? " (not really)" : "");
+      if (host_checking || f.running_in_test_harness)
 	continue;
 
-      save_sender = sender_address;
-      sender_address = recipient;
-      send_status = moan_to_sender(ERRMESS_DMARC_FORENSIC, eblock,
-				   header_list, message_file, FALSE);
-      sender_address = save_sender;
-      if (!send_status)
+      if (!moan_send_message(recipient, ERRMESS_DMARC_FORENSIC, eblock,
+			    header_list, message_file, NULL))
 	log_write(0, LOG_MAIN|LOG_PANIC,
 	  "failure to send DMARC forensic report to %s", recipient);
       }
     }
 }
 
+
+/* Look up a DNS dmarc record for the given domain.  Return it or NULL */
+
+static uschar *
+dmarc_dns_lookup(uschar * dom)
+{
+dns_answer * dnsa = store_get_dns_answer();
+dns_scan dnss;
+int rc = dns_lookup(dnsa, string_sprintf("_dmarc.%s", dom), T_TXT, NULL);
+
+if (rc == DNS_SUCCEED)
+  for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
+       rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
+    if (rr->type == T_TXT && rr->size > 3)
+      return string_copyn(US rr->data, rr->size);
+return NULL;
+}
+
+
 /* dmarc_process adds the envelope sender address to the existing
 context (if any), retrieves the result, sets up expansion
 strings and evaluates the condition outcome. */
@@ -222,11 +234,12 @@ int sr, origin;             /* used in SPF section */
 int dmarc_spf_result  = 0;  /* stores spf into dmarc conn ctx */
 int tmp_ans, c;
 pdkim_signature * sig = dkim_signatures;
+uschar * rr;
 BOOL has_dmarc_record = TRUE;
 u_char **ruf; /* forensic report addressees, if called for */
 
 /* ACLs have "control=dmarc_disable_verify" */
-if (dmarc_disable_verify)
+if (f.dmarc_disable_verify)
   return OK;
 
 /* Store the header From: sender domain for this part of DMARC.
@@ -247,7 +260,7 @@ else if (!dmarc_abort)
   uschar * p;
   uschar saveend;
 
-  parse_allow_group = TRUE;
+  f.parse_allow_group = TRUE;
   p = parse_find_address_end(from_header->text, FALSE);
   saveend = *p; *p = '\0';
   if ((header_from_sender = parse_extract_address(from_header->text, &errormsg,
@@ -366,7 +379,15 @@ if (!dmarc_abort && !sender_host_authenticated)
 					 sig->domain, dkim_ares_result);
     sig = sig->next;
     }
-  libdm_status = opendmarc_policy_query_dmarc(dmarc_pctx, US"");
+
+  /* Look up DMARC policy record in DNS.  We do this explicitly, rather than
+  letting the dmarc library do it with opendmarc_policy_query_dmarc(), so that
+  our dns access path is used for debug tracing and for the testsuite
+  diversion. */
+
+  libdm_status = (rr = dmarc_dns_lookup(header_from_sender))
+    ? opendmarc_policy_store_dmarc(dmarc_pctx, rr, header_from_sender, NULL)
+    : DMARC_DNS_ERROR_NO_RECORD;
   switch (libdm_status)
     {
     case DMARC_DNS_ERROR_NXDOMAIN:
@@ -406,11 +427,11 @@ if (!dmarc_abort && !sender_host_authenticated)
   /* Can't use exim's string manipulation functions so allocate memory
   for libopendmarc using its max hostname length definition. */
 
-  dmarc_domain = US calloc(DMARC_MAXHOSTNAMELEN, sizeof(uschar));
+  dmarc_domain = store_get(DMARC_MAXHOSTNAMELEN, TRUE);
   libdm_status = opendmarc_policy_fetch_utilized_domain(dmarc_pctx,
     dmarc_domain, DMARC_MAXHOSTNAMELEN-1);
-  dmarc_used_domain = string_copy(dmarc_domain);
-  free(dmarc_domain);
+  store_release_above(dmarc_domain + Ustrlen(dmarc_domain)+1);
+  dmarc_used_domain = dmarc_domain;
 
   if (libdm_status != DMARC_PARSE_OKAY)
     log_write(0, LOG_MAIN|LOG_PANIC,
@@ -487,7 +508,7 @@ if (!dmarc_abort && !sender_host_authenticated)
 /* shut down libopendmarc */
 if (dmarc_pctx)
   (void) opendmarc_policy_connect_shutdown(dmarc_pctx);
-if (!dmarc_disable_verify)
+if (!f.dmarc_disable_verify)
   (void) opendmarc_policy_library_shutdown(&dmarc_ctx);
 
 return OK;
@@ -558,8 +579,8 @@ history_buffer = string_sprintf(
 /* Write the contents to the history file */
 DEBUG(D_receive)
   debug_printf("DMARC logging history data for opendmarc reporting%s\n",
-	     (host_checking || running_in_test_harness) ? " (not really)" : "");
-if (host_checking || running_in_test_harness)
+	     (host_checking || f.running_in_test_harness) ? " (not really)" : "");
+if (host_checking || f.running_in_test_harness)
   {
   DEBUG(D_receive)
     debug_printf("DMARC history data for debugging:\n%s", history_buffer);
@@ -584,7 +605,7 @@ return DMARC_HIST_OK;
 uschar *
 dmarc_exim_expand_query(int what)
 {
-if (dmarc_disable_verify || !dmarc_pctx)
+if (f.dmarc_disable_verify || !dmarc_pctx)
   return dmarc_exim_expand_defaults(what);
 
 if (what == DMARC_VERIFY_STATUS)
@@ -596,7 +617,7 @@ uschar *
 dmarc_exim_expand_defaults(int what)
 {
 if (what == DMARC_VERIFY_STATUS)
-  return dmarc_disable_verify ?  US"off" : US"none";
+  return f.dmarc_disable_verify ?  US"off" : US"none";
 return US"";
 }
 
@@ -604,7 +625,7 @@ return US"";
 gstring *
 authres_dmarc(gstring * g)
 {
-if (dmarc_has_been_checked)
+if (f.dmarc_has_been_checked)
   {
   g = string_append(g, 2, US";\n\tdmarc=", dmarc_pass_fail);
   if (header_from_sender)
@@ -614,6 +635,6 @@ return g;
 }
 
 # endif /* SUPPORT_SPF */
-#endif /* EXPERIMENTAL_DMARC */
+#endif /* SUPPORT_DMARC */
 /* vi: aw ai sw=2
  */