dnsdb tlsa lookup

[exim.git] / src / src / lookups / dnsdb.c

diff --git a/src/src/lookups/dnsdb.c b/src/src/lookups/dnsdb.c
index de62defa780f269585f1d2d27c698952b32ed283..beba0950801af6722305a1c24bd72f9f20060ef0 100644 (file)
--- a/src/src/lookups/dnsdb.c
+++ b/src/src/lookups/dnsdb.c
@@ -1,15 +1,12 @@
-/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.15 2005/12/06 10:25:59 ph10 Exp $ */
-

 /*************************************************
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 
 /*************************************************
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 

-/* Copyright (c) University of Cambridge 1995 - 2005 */
+/* Copyright (c) University of Cambridge 1995 - 2012 */

 /* See the file NOTICE for conditions of use and distribution. */
 
 #include "../exim.h"
 #include "lf_functions.h"
 /* See the file NOTICE for conditions of use and distribution. */
 
 #include "../exim.h"
 #include "lf_functions.h"

-#include "dnsdb.h"

 
 
 
 
 
 


@@ -20,11 +17,22 @@ header files. */
 #define T_TXT 16
 #endif
 
 #define T_TXT 16
 #endif
 

+/* Many systems do not have T_SPF. */
+#ifndef T_SPF
+#define T_SPF 99
+#endif
+
+/* New TLSA record for DANE */
+#ifndef T_TLSA
+#define T_TLSA 52
+#endif
+

 /* Table of recognized DNS record types and their integer values. */
 
 /* Table of recognized DNS record types and their integer values. */
 

-static char *type_names[] = {
+static const char *type_names[] = {

   "a",
 #if HAVE_IPV6
   "a",
 #if HAVE_IPV6

+  "a+",

   "aaaa",
   #ifdef SUPPORT_A6
   "a6",
   "aaaa",
   #ifdef SUPPORT_A6
   "a6",


@@ -36,7 +44,9 @@ static char *type_names[] = {
   "mxh",
   "ns",
   "ptr",
   "mxh",
   "ns",
   "ptr",

+  "spf",

   "srv",
   "srv",

+  "tlsa",

   "txt",
   "zns"
 };
   "txt",
   "zns"
 };


@@ -44,6 +54,7 @@ static char *type_names[] = {
 static int type_values[] = {
   T_A,
 #if HAVE_IPV6
 static int type_values[] = {
   T_A,
 #if HAVE_IPV6

+  T_APL,     /* Private type for AAAA + A */

   T_AAAA,
   #ifdef SUPPORT_A6
   T_A6,
   T_AAAA,
   #ifdef SUPPORT_A6
   T_A6,


@@ -55,7 +66,9 @@ static int type_values[] = {
   T_MXH,     /* Private type for "MX hostnames" */
   T_NS,
   T_PTR,
   T_MXH,     /* Private type for "MX hostnames" */
   T_NS,
   T_PTR,

+  T_SPF,

   T_SRV,
   T_SRV,

+  T_TLSA,

   T_TXT,
   T_ZNS      /* Private type for "zone nameservers" */
 };
   T_TXT,
   T_ZNS      /* Private type for "zone nameservers" */
 };


@@ -67,7 +80,7 @@ static int type_values[] = {
 
 /* See local README for interface description. */
 
 
 /* See local README for interface description. */
 

-void *
+static void *

 dnsdb_open(uschar *filename, uschar **errmsg)
 {
 filename = filename;   /* Keep picky compilers happy */
 dnsdb_open(uschar *filename, uschar **errmsg)
 {
 filename = filename;   /* Keep picky compilers happy */


@@ -88,21 +101,28 @@ consist of a number of parts.
 separator character that is used when multiple records are found. The default
 separator is newline.
 
 separator character that is used when multiple records are found. The default
 separator is newline.
 

-(b) If the next sequence of characters is 'defer_FOO' followed by a comma,
+(b) If the next character is ',' then the next character is the separator
+character used for multiple items of text in "TXT" records. Alternatively,
+if the next character is ';' then these multiple items are concatenated with
+no separator. With neither of these options specified, only the first item
+is output.  Similarly for "SPF" records, but the default for joining multiple
+items in one SPF record is the empty string, for direct concatenation.
+
+(c) If the next sequence of characters is 'defer_FOO' followed by a comma,

 the defer behaviour is set to FOO. The possible behaviours are: 'strict', where
 any defer causes the whole lookup to defer; 'lax', where a defer causes the
 whole lookup to defer only if none of the DNS queries succeeds; and 'never',
 where all defers are as if the lookup failed. The default is 'lax'.
 
 the defer behaviour is set to FOO. The possible behaviours are: 'strict', where
 any defer causes the whole lookup to defer; 'lax', where a defer causes the
 whole lookup to defer only if none of the DNS queries succeeds; and 'never',
 where all defers are as if the lookup failed. The default is 'lax'.
 

-(c) If the next sequence of characters is a sequence of letters and digits
+(d) If the next sequence of characters is a sequence of letters and digits

 followed by '=', it is interpreted as the name of the DNS record type. The
 default is "TXT".
 
 followed by '=', it is interpreted as the name of the DNS record type. The
 default is "TXT".
 

-(d) Then there follows list of domain names. This is a generalized Exim list,
+(e) Then there follows list of domain names. This is a generalized Exim list,

 which may start with '<' in order to set a specific separator. The default
 separator, as always, is colon. */
 
 which may start with '<' in order to set a specific separator. The default
 separator, as always, is colon. */
 

-int
+static int

 dnsdb_find(void *handle, uschar *filename, uschar *keystring, int length,
   uschar **result, uschar **errmsg, BOOL *do_cache)
 {
 dnsdb_find(void *handle, uschar *filename, uschar *keystring, int length,
   uschar **result, uschar **errmsg, BOOL *do_cache)
 {


@@ -111,9 +131,10 @@ int size = 256;
 int ptr = 0;
 int sep = 0;
 int defer_mode = PASS;
 int ptr = 0;
 int sep = 0;
 int defer_mode = PASS;

-int type = T_TXT;
+int type;

 int failrc = FAIL;
 uschar *outsep = US"\n";
 int failrc = FAIL;
 uschar *outsep = US"\n";

+uschar *outsep2 = NULL;

 uschar *equals, *domain, *found;
 uschar buffer[256];
 
 uschar *equals, *domain, *found;
 uschar buffer[256];
 


@@ -131,13 +152,24 @@ filename = filename;
 length = length;
 do_cache = do_cache;
 
 length = length;
 do_cache = do_cache;
 

-/* If the string starts with '>' we change the output separator */
+/* If the string starts with '>' we change the output separator.
+If it's followed by ';' or ',' we set the TXT output separator. */

 
 while (isspace(*keystring)) keystring++;
 if (*keystring == '>')
   {
   outsep = keystring + 1;
   keystring += 2;
 
 while (isspace(*keystring)) keystring++;
 if (*keystring == '>')
   {
   outsep = keystring + 1;
   keystring += 2;

+  if (*keystring == ',')
+    {
+    outsep2 = keystring + 1;
+    keystring += 2;
+    }
+  else if (*keystring == ';')
+    {
+    outsep2 = US"";
+    keystring++;
+    }

   while (isspace(*keystring)) keystring++;
   }
 
   while (isspace(*keystring)) keystring++;
   }
 


@@ -175,8 +207,10 @@ if (strncmpic(keystring, US"defer_", 6) == 0)
   while (isspace(*keystring)) keystring++;
   }
 
   while (isspace(*keystring)) keystring++;
   }
 

-/* If the keystring contains an = this must be preceded by a valid type name. */
+/* Figure out the "type" value if it is not T_TXT.
+If the keystring contains an = this must be preceded by a valid type name. */

 
 

+type = T_TXT;

 if ((equals = Ustrchr(keystring, '=')) != NULL)
   {
   int i, len;
 if ((equals = Ustrchr(keystring, '=')) != NULL)
   {
   int i, len;


@@ -224,6 +258,14 @@ if (type == T_PTR && keystring[0] != '<' &&
     string_is_ip_address(keystring, NULL) != 0)
   sep = -1;
 
     string_is_ip_address(keystring, NULL) != 0)
   sep = -1;
 

+/* SPF strings should be concatenated without a separator, thus make
+it the default if not defined (see RFC 4408 section 3.1.3).
+Multiple SPF records are forbidden (section 3.1.2) but are currently
+not handled specially, thus they are concatenated with \n by default. */
+
+if (type == T_SPF && outsep2 == NULL)
+  outsep2 = US"";
+

 /* Now scan the list and do a lookup for each item */
 
 while ((domain = string_nextinlist(&keystring, &sep, buffer, sizeof(buffer)))
 /* Now scan the list and do a lookup for each item */
 
 while ((domain = string_nextinlist(&keystring, &sep, buffer, sizeof(buffer)))


@@ -247,139 +289,203 @@ while ((domain = string_nextinlist(&keystring, &sep, buffer, sizeof(buffer)))
     domain = rbuffer;
     }
 
     domain = rbuffer;
     }
 

-  DEBUG(D_lookup) debug_printf("dnsdb key: %s\n", domain);
-
-  /* Do the lookup and sort out the result. There are three special types that
-  are handled specially: T_CSA, T_ZNS and T_MXH. The former two are handled in
-  a special lookup function so that the facility could be used from other
-  parts of the Exim code. The latter affects only what happens later on in
-  this function, but for tidiness it is handled in a similar way. If the
-  lookup fails, continue with the next domain. In the case of DEFER, adjust
-  the final "nothing found" result, but carry on to the next domain. */
-
-  found = domain;
-  rc = dns_special_lookup(&dnsa, domain, type, &found);
-
-  if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue;
-  if (rc != DNS_SUCCEED)
+  do

     {
     {

-    if (defer_mode == DEFER) return DEFER;          /* always defer */
-      else if (defer_mode == PASS) failrc = DEFER;  /* defer only if all do */
-    continue;                                       /* treat defer as fail */
-    }
-
-  /* Search the returned records */
+    DEBUG(D_lookup) debug_printf("dnsdb key: %s\n", domain);
+
+    /* Do the lookup and sort out the result. There are four special types that
+    are handled specially: T_CSA, T_ZNS, T_APL and T_MXH.
+    The first two are handled in a special lookup function so that the facility
+    could be used from other parts of the Exim code. T_APL is handled by looping
+    over the types of A lookup.  T_MXH affects only what happens later on in
+    this function, but for tidiness it is handled by the "special". If the
+    lookup fails, continue with the next domain. In the case of DEFER, adjust
+    the final "nothing found" result, but carry on to the next domain. */
+
+    found = domain;
+#if HAVE_IPV6
+    if (type == T_APL)         /* NB cannot happen unless HAVE_IPV6 */
+      {
+      if (searchtype == T_APL)
+# if defined(SUPPORT_A6)
+                                     searchtype = T_A6;
+# else
+                                     searchtype = T_AAAA;
+# endif
+      else if (searchtype == T_A6)   searchtype = T_AAAA;
+      else if (searchtype == T_AAAA) searchtype = T_A;
+      rc = dns_special_lookup(&dnsa, domain, searchtype, &found);
+      }
+    else
+#endif
+      rc = dns_special_lookup(&dnsa, domain, type, &found);

 
 

-  for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
-       rr != NULL;
-       rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
-    {
-    if (rr->type != searchtype) continue;
+    if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue;
+    if (rc != DNS_SUCCEED)
+      {
+      if (defer_mode == DEFER) return DEFER;          /* always defer */
+      if (defer_mode == PASS) failrc = DEFER;         /* defer only if all do */
+      continue;                                       /* treat defer as fail */
+      }

 
 

-    /* There may be several addresses from an A6 record. Put the configured
-    separator between them, just as for between several records. However, A6
-    support is not normally configured these days. */
+    /* Search the returned records */

 
 

-    if (type == T_A ||
-        #ifdef SUPPORT_A6
-        type == T_A6 ||
-        #endif
-        type == T_AAAA)
+    for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
+         rr != NULL;
+         rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))

       {
       {

-      dns_address *da;
-      for (da = dns_address_from_rr(&dnsa, rr); da != NULL; da = da->next)
+      if (rr->type != searchtype) continue;
+
+      /* There may be several addresses from an A6 record. Put the configured
+      separator between them, just as for between several records. However, A6
+      support is not normally configured these days. */
+
+      if (type == T_A ||
+          #ifdef SUPPORT_A6
+          type == T_A6 ||
+          #endif
+          type == T_AAAA ||
+         type == T_APL)

         {
         {

-        if (ptr != 0) yield = string_cat(yield, &size, &ptr, outsep, 1);
-        yield = string_cat(yield, &size, &ptr, da->address,
-          Ustrlen(da->address));
+        dns_address *da;
+        for (da = dns_address_from_rr(&dnsa, rr); da != NULL; da = da->next)
+          {
+          if (ptr != 0) yield = string_cat(yield, &size, &ptr, outsep, 1);
+          yield = string_cat(yield, &size, &ptr, da->address,
+            Ustrlen(da->address));
+          }
+        continue;

         }
         }

-      continue;
-      }

 
 

-    /* Other kinds of record just have one piece of data each, but there may be
-    several of them, of course. */
+      /* Other kinds of record just have one piece of data each, but there may be
+      several of them, of course. */

 
 

-    if (ptr != 0) yield = string_cat(yield, &size, &ptr, outsep, 1);
+      if (ptr != 0) yield = string_cat(yield, &size, &ptr, outsep, 1);

 
 

-    if (type == T_TXT)
-      {
-      yield = string_cat(yield, &size, &ptr, (uschar *)(rr->data+1),
-        (rr->data)[0]);
-      }
-    else   /* T_CNAME, T_CSA, T_MX, T_MXH, T_NS, T_PTR, T_SRV */
-      {
-      int priority, weight, port;
-      uschar s[264];
-      uschar *p = (uschar *)(rr->data);
-
-      if (type == T_MXH)
+      if (type == T_TXT || type == T_SPF)

         {
         {

-        /* mxh ignores the priority number and includes only the hostnames */
-        GETSHORT(priority, p);
-        }
-      else if (type == T_MX)
-        {
-        GETSHORT(priority, p);
-        sprintf(CS s, "%d ", priority);
-        yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
+        if (outsep2 == NULL)
+          {
+          /* output only the first item of data */
+          yield = string_cat(yield, &size, &ptr, (uschar *)(rr->data+1),
+            (rr->data)[0]);
+          }
+        else
+          {
+          /* output all items */
+          int data_offset = 0;
+          while (data_offset < rr->size)
+            {
+            uschar chunk_len = (rr->data)[data_offset++];
+            if (outsep2[0] != '\0' && data_offset != 1)
+              yield = string_cat(yield, &size, &ptr, outsep2, 1);
+            yield = string_cat(yield, &size, &ptr,
+                             (uschar *)((rr->data)+data_offset), chunk_len);
+            data_offset += chunk_len;
+            }
+          }

         }
         }

-      else if (type == T_SRV)
+      else if (type == T_TLSA)

         {
         {

-        GETSHORT(priority, p);
-        GETSHORT(weight, p);
-        GETSHORT(port, p);
-        sprintf(CS s, "%d %d %d ", priority, weight, port);
+        uint8_t usage, selector, matching_type;
+        uint16_t i, payload_length;
+        uschar s[MAX_TLSA_EXPANDED_SIZE];
+       uschar * sp = s;
+        uschar *p = (uschar *)(rr->data);
+
+        usage = *p++;
+        selector = *p++;
+        matching_type = *p++;
+        /* What's left after removing the first 3 bytes above */
+        payload_length = rr->size - 3;
+        sp += sprintf(CS s, "%d %d %d ", usage, selector, matching_type);
+        /* Now append the cert/identifier, one hex char at a time */
+        for (i=0;
+             i < payload_length && sp-s < (MAX_TLSA_EXPANDED_SIZE - 4);
+             i++)
+          {
+          sp += sprintf(CS sp, "%02x", (unsigned char)p[i]);
+          }

         yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
         }
         yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
         }

-      else if (type == T_CSA)
+      else   /* T_CNAME, T_CSA, T_MX, T_MXH, T_NS, T_PTR, T_SRV */

         {
         {

-        /* See acl_verify_csa() for more comments about CSA. */
-
-        GETSHORT(priority, p);
-        GETSHORT(weight, p);
-        GETSHORT(port, p);
-
-        if (priority != 1) continue;      /* CSA version must be 1 */
+        int priority, weight, port;
+        uschar s[264];
+        uschar *p = (uschar *)(rr->data);

 
 

-        /* If the CSA record we found is not the one we asked for, analyse
-        the subdomain assertions in the port field, else analyse the direct
-        authorization status in the weight field. */
-
-        if (found != domain)
+        if (type == T_MXH)

           {
           {

-          if (port & 1) *s = 'X';         /* explicit authorization required */
-          else *s = '?';                  /* no subdomain assertions here */
+          /* mxh ignores the priority number and includes only the hostnames */
+          GETSHORT(priority, p);

           }
           }

-        else
+        else if (type == T_MX)

           {
           {

-          if (weight < 2) *s = 'N';       /* not authorized */
-          else if (weight == 2) *s = 'Y'; /* authorized */
-          else if (weight == 3) *s = '?'; /* unauthorizable */
-          else continue;                  /* invalid */
+          GETSHORT(priority, p);
+          sprintf(CS s, "%d ", priority);
+          yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
+          }
+        else if (type == T_SRV)
+          {
+          GETSHORT(priority, p);
+          GETSHORT(weight, p);
+          GETSHORT(port, p);
+          sprintf(CS s, "%d %d %d ", priority, weight, port);
+          yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
+          }
+        else if (type == T_CSA)
+          {
+          /* See acl_verify_csa() for more comments about CSA. */
+
+          GETSHORT(priority, p);
+          GETSHORT(weight, p);
+          GETSHORT(port, p);
+
+          if (priority != 1) continue;      /* CSA version must be 1 */
+
+          /* If the CSA record we found is not the one we asked for, analyse
+          the subdomain assertions in the port field, else analyse the direct
+          authorization status in the weight field. */
+
+          if (found != domain)
+            {
+            if (port & 1) *s = 'X';         /* explicit authorization required */
+            else *s = '?';                  /* no subdomain assertions here */
+            }
+          else
+            {
+            if (weight < 2) *s = 'N';       /* not authorized */
+            else if (weight == 2) *s = 'Y'; /* authorized */
+            else if (weight == 3) *s = '?'; /* unauthorizable */
+            else continue;                  /* invalid */
+            }
+
+          s[1] = ' ';
+          yield = string_cat(yield, &size, &ptr, s, 2);

           }
 
           }
 

-        s[1] = ' ';
-        yield = string_cat(yield, &size, &ptr, s, 2);
-        }
-
-      /* GETSHORT() has advanced the pointer to the target domain. */
+        /* GETSHORT() has advanced the pointer to the target domain. */

 
 

-      rc = dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, p,
-        (DN_EXPAND_ARG4_TYPE)(s), sizeof(s));
+        rc = dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, p,
+          (DN_EXPAND_ARG4_TYPE)(s), sizeof(s));

 
 

-      /* If an overlong response was received, the data will have been
-      truncated and dn_expand may fail. */
+        /* If an overlong response was received, the data will have been
+        truncated and dn_expand may fail. */

 
 

-      if (rc < 0)
-        {
-        log_write(0, LOG_MAIN, "host name alias list truncated: type=%s "
-          "domain=%s", dns_text_type(type), domain);
-        break;
+        if (rc < 0)
+          {
+          log_write(0, LOG_MAIN, "host name alias list truncated: type=%s "
+            "domain=%s", dns_text_type(type), domain);
+          break;
+          }
+        else yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));

         }
         }

-      else yield = string_cat(yield, &size, &ptr, s, Ustrlen(s));
-      }
-    }    /* Loop for list of returned records */
-  }      /* Loop for list of domains */
+      }    /* Loop for list of returned records */
+
+           /* Loop for set of A-lookupu types */
+    } while (type == T_APL && searchtype != T_A);
+
+  }        /* Loop for list of domains */

 
 /* Reclaim unused memory */
 
 
 /* Reclaim unused memory */
 


@@ -394,4 +500,42 @@ yield[ptr] = 0;
 return OK;
 }
 
 return OK;
 }
 

+
+
+/*************************************************
+*         Version reporting entry point          *
+*************************************************/
+
+/* See local README for interface description. */
+
+#include "../version.h"
+
+void
+dnsdb_version_report(FILE *f)
+{
+#ifdef DYNLOOKUP
+fprintf(f, "Library version: DNSDB: Exim version %s\n", EXIM_VERSION_STR);
+#endif
+}
+
+
+static lookup_info _lookup_info = {
+  US"dnsdb",                     /* lookup name */
+  lookup_querystyle,             /* query style */
+  dnsdb_open,                    /* open function */
+  NULL,                          /* check function */
+  dnsdb_find,                    /* find function */
+  NULL,                          /* no close function */
+  NULL,                          /* no tidy function */
+  NULL,                          /* no quoting function */
+  dnsdb_version_report           /* version reporting */
+};
+
+#ifdef DYNLOOKUP
+#define dnsdb_lookup_module_info _lookup_module_info
+#endif
+
+static lookup_info *_lookup_list[] = { &_lookup_info };
+lookup_module_info dnsdb_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
+

 /* End of lookups/dnsdb.c */
 /* End of lookups/dnsdb.c */