Dnssec observability: add variable $lookup_dnssec_authenticated

9 files changed, 43 insertions, 3 deletions

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 4370aa0b5..0e6a38bd9 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -6981,6 +6981,8 @@ ${lookup dnsdb{a=one.host.com:two.host.com}}
 Thus, in the default case, as long as at least one of the DNS lookups
 yields some data, the lookup succeeds.
 
+.new
+.cindex "DNSSEC" "dns lookup"
 Use of &(DNSSEC)& is controlled by a dnssec modifier.
 The possible keywords are
 &"dnssec_strict"&, &"dnssec_lax"&, and &"dnssec_never"&.
@@ -6991,6 +6993,9 @@ is not labelled as authenticated data
 is treated as equivalent to a temporary DNS error.
 The default is &"never"&.
 
+See also the &$lookup_dnssec_authenticated$& variable.
+.wen
+
 
 
 
@@ -11448,6 +11453,16 @@ ability to find the amount of free space (only true for experimental systems),
 the space value is -1. See also the &%check_log_space%& option.
 
 
+.new
+.vitem &$lookup_dnssec_authenticated$&
+.vindex "&$lookup_dnssec_authenticated$&"
+This variable is set after a DNS lookup done by
+either a dnslookup router or a dnsdb lookup expansion.
+It will be empty if &(DNSSEC)& was not requested,
+&"no"& if the result was not labelled as authenticated data
+and &"yes"& if it was.
+.wen
+
 .vitem &$mailstore_basename$&
 .vindex "&$mailstore_basename$&"
 This variable is set only when doing deliveries in &"mailstore"& format in the
@@ -17649,6 +17664,7 @@ when there is a DNS lookup error.
 
 
 
+.new
 .option dnssec_request_domains dnslookup "domain list&!!" unset
 .cindex "MX record" "security"
 .cindex "DNSSEC" "MX lookup"
@@ -17658,8 +17674,12 @@ DNS lookups for domains matching &%dnssec_request_domains%& will be done with
 the dnssec request bit set.
 This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
 
+See also the &$lookup_dnssec_authenticated$& variable.
+.wen
+
 
 
+.new
 .option dnssec_require_domains dnslookup "domain list&!!" unset
 .cindex "MX record" "security"
 .cindex "DNSSEC" "MX lookup"
@@ -17669,6 +17689,7 @@ DNS lookups for domains matching &%dnssec_request_domains%& will be done with
 the dnssec request bit set.  Any returns not having the Authenticated Data bit
 (AD bit) set wil be ignored and logged as a host-lookup failure.
 This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
+.wen
 
 
 
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 8bf42d537..ddbd91135 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -92,6 +92,7 @@ TL/08 Bugzilla 1453: New LDAP "SERVERS=" option allows admin to override list
       Schlichting.
 
 JH/18 New options dnssec_lax, dnssec_strict on dnsdb lookups.
+      New variable $lookup_dnssec_authenticated for observability.
 
 TL/09 Bugzilla 609: Add -C option to exiqgrep, specify which exim.conf to use.
       Patch submitted by Lars Timman.
diff --git a/src/src/acl.c b/src/src/acl.c
index 9d0842c1d..270a2f2c0 100644
--- a/src/src/acl.c
+++ b/src/src/acl.c
@@ -1614,6 +1614,7 @@ else
 DNS_LOOKUP_AGAIN:
 #endif
 
+lookup_dnssec_authenticated = NULL;
 switch (dns_lookup(&dnsa, target, type, NULL))
   {
   /* If something bad happened (most commonly DNS_AGAIN), defer. */
diff --git a/src/src/dkim.c b/src/src/dkim.c
index cb7fc7065..171fcccdb 100644
--- a/src/src/dkim.c
+++ b/src/src/dkim.c
@@ -23,6 +23,7 @@ int dkim_exim_query_dns_txt(char *name, char *answer) {
   dns_scan   dnss;
   dns_record *rr;
 
+  lookup_dnssec_authenticated = NULL;
   if (dns_lookup(&dnsa, (uschar *)name, T_TXT, NULL) != DNS_SUCCEED) return PDKIM_FAIL;
 
   /* Search for TXT record */
diff --git a/src/src/expand.c b/src/src/expand.c
index fd4f65abb..54b3abc54 100644
--- a/src/src/expand.c
+++ b/src/src/expand.c
@@ -510,6 +510,7 @@ static var_entry var_table[] = {
   { "localhost_number",    vtype_int,         &host_number },
   { "log_inodes",          vtype_pinodes,     (void *)FALSE },
   { "log_space",           vtype_pspace,      (void *)FALSE },
+  { "lookup_dnssec_authenticated",vtype_stringptr,&lookup_dnssec_authenticated},
   { "mailstore_basename",  vtype_stringptr,   &mailstore_basename },
 #ifdef WITH_CONTENT_SCAN
   { "malware_name",        vtype_stringptr,   &malware_name },
diff --git a/src/src/globals.c b/src/src/globals.c
index fbc3787f9..cb014fbe8 100644
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -837,6 +837,7 @@ BOOL    log_testing_mode       = FALSE;
 BOOL    log_timezone           = FALSE;
 unsigned int log_write_selector= L_default;
 uschar *login_sender_address   = NULL;
+uschar *lookup_dnssec_authenticated = NULL;
 int     lookup_open_max        = 25;
 uschar *lookup_value           = NULL;
 
diff --git a/src/src/globals.h b/src/src/globals.h
index e18bddc01..cfa6d2bff 100644
--- a/src/src/globals.h
+++ b/src/src/globals.h
@@ -503,6 +503,7 @@ extern unsigned int log_write_selector;/* Bit map of logging options for log_wri
 extern uschar *login_sender_address;   /* The actual sender address */
 extern lookup_info **lookup_list;      /* Array of pointers to available lookups */
 extern int     lookup_list_count;      /* Number of entries in the list */
+extern uschar *lookup_dnssec_authenticated; /* AD status of dns lookup */
 extern int     lookup_open_max;        /* Max lookup files to cache */
 extern uschar *lookup_value;           /* Value looked up from file */
 
diff --git a/src/src/host.c b/src/src/host.c
index 495a44d58..05bcbe8c7 100644
--- a/src/src/host.c
+++ b/src/src/host.c
@@ -220,6 +220,8 @@ else
   int rc = dns_lookup(&dnsa, lname, type, NULL);
   int count = 0;
 
+  lookup_dnssec_authenticated = NULL;
+
   switch(rc)
     {
     case DNS_SUCCEED: break;
@@ -2207,7 +2209,7 @@ Returns:       HOST_FIND_FAILED     couldn't find A record
 static int
 set_address_from_dns(host_item *host, host_item **lastptr,
   uschar *ignore_target_hosts, BOOL allow_ip, uschar **fully_qualified_name,
-  BOOL dnssec_require)
+  BOOL dnssec_requested, BOOL dnssec_require)
 {
 dns_record *rr;
 host_item *thishostlast = NULL;    /* Indicates not yet filled in anything */
@@ -2268,6 +2270,8 @@ for (; i >= 0; i--)
   dns_scan dnss;
 
   int rc = dns_lookup(&dnsa, host->name, type, fully_qualified_name);
+  lookup_dnssec_authenticated = !dnssec_requested ? NULL
+    : dns_is_secure(&dnsa) ? US"yes" : US"no";
 
   /* We want to return HOST_FIND_AGAIN if one of the A, A6, or AAAA lookups
   fails or times out, but not if another one succeeds. (In the early
@@ -2506,6 +2510,9 @@ if ((whichrrs & HOST_FIND_BY_SRV) != 0)
   magic. */
 
   rc = dns_lookup(&dnsa, buffer, ind_type, &temp_fully_qualified_name);
+  lookup_dnssec_authenticated = !dnssec_request ? NULL
+    : dns_is_secure(&dnsa) ? US"yes" : US"no";
+
   if (temp_fully_qualified_name != buffer && fully_qualified_name != NULL)
     *fully_qualified_name = temp_fully_qualified_name + prefix_length;
 
@@ -2541,6 +2548,9 @@ if (rc != DNS_SUCCEED && (whichrrs & HOST_FIND_BY_MX) != 0)
   {
   ind_type = T_MX;
   rc = dns_lookup(&dnsa, host->name, ind_type, fully_qualified_name);
+  lookup_dnssec_authenticated = !dnssec_request ? NULL
+    : dns_is_secure(&dnsa) ? US"yes" : US"no";
+
   switch (rc)
     {
     case DNS_NOMATCH:
@@ -2584,7 +2594,7 @@ if (rc != DNS_SUCCEED)
   host->mx = MX_NONE;
   host->port = PORT_NONE;
   rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE,
-    fully_qualified_name, dnssec_require);
+    fully_qualified_name, dnssec_request, dnssec_require);
 
   /* If one or more address records have been found, check that none of them
   are local. Since we know the host items all have their IP addresses
@@ -2914,7 +2924,7 @@ for (h = host; h != last->next; h = h->next)
   {
   if (h->address != NULL) continue;  /* Inserted by a multihomed host */
   rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip,
-    NULL, dnssec_require);
+    NULL, dnssec_request, dnssec_require);
   if (rc != HOST_FOUND)
     {
     h->status = hstatus_unusable;
diff --git a/src/src/lookups/dnsdb.c b/src/src/lookups/dnsdb.c
index b7e50588b..ef3376505 100644
--- a/src/src/lookups/dnsdb.c
+++ b/src/src/lookups/dnsdb.c
@@ -354,6 +354,9 @@ while ((domain = string_nextinlist(&keystring, &sep, buffer, sizeof(buffer)))
 #endif
       rc = dns_special_lookup(&dnsa, domain, type, &found);
 
+    lookup_dnssec_authenticated = dnssec_mode==OK ? NULL
+      : dns_is_secure(&dnsa) ? US"yes" : US"no";
+
     if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue;
     if (rc != DNS_SUCCEED)
       {