Fix taint-handling in rDNS name construction

[user/henk/code/exim.git] / src / src / verify.c

diff --git a/src/src/verify.c b/src/src/verify.c
index 84c582cfa340dcee53ba731ee9b4c7f5c3ed50ef..fc8cd84ea91f50119f2616c50d452a3ab4bd950a 100644 (file)
--- a/src/src/verify.c
+++ b/src/src/verify.c
@@ -3396,7 +3396,7 @@ if (  (t = tree_search(dnsbl_cache, query))
 /* Previous lookup was cached */
 
   {
 /* Previous lookup was cached */
 
   {

-  HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
+  HDEBUG(D_dnsbl) debug_printf("dnslists: using result of previous lookup\n");

   }
 
 /* If not cached from a previous lookup, we must do a DNS lookup, and
   }
 
 /* If not cached from a previous lookup, we must do a DNS lookup, and


@@ -3404,7 +3404,7 @@ cache the result in permanent memory. */
 
 else
   {
 
 else
   {

-  uint ttl = 3600;
+  uint ttl = 3600;     /* max TTL for positive cache entries */

 
   store_pool = POOL_PERM;
 
 
   store_pool = POOL_PERM;
 


@@ -3439,34 +3439,58 @@ else
   addresses generated in that way as well.
 
   Mark the cache entry with the "now" plus the minimum of the address TTLs,
   addresses generated in that way as well.
 
   Mark the cache entry with the "now" plus the minimum of the address TTLs,

-  or some suitably far-future time if none were found. */
+  or the RFC 2308 negative-cache value from the SOA if none were found. */

 
 

-  if (cb->rc == DNS_SUCCEED)
+  switch (cb->rc)

     {
     {

-    dns_address ** addrp = &(cb->rhs);
-    for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
-         rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
-      if (rr->type == T_A)
-        {
-        dns_address *da = dns_address_from_rr(dnsa, rr);
-        if (da)
-          {
-          *addrp = da;
-          while (da->next) da = da->next;
-          addrp = &da->next;
+    case DNS_SUCCEED:
+      {
+      dns_address ** addrp = &cb->rhs;
+      dns_address * da;
+      for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
+          rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
+       if (rr->type == T_A && (da = dns_address_from_rr(dnsa, rr)))
+         {
+         *addrp = da;
+         while (da->next) da = da->next;
+         addrp = &da->next;

          if (ttl > rr->ttl) ttl = rr->ttl;
          if (ttl > rr->ttl) ttl = rr->ttl;

-          }
-        }
+         }
+
+      if (cb->rhs)
+       {
+       cb->expiry = time(NULL) + ttl;
+       break;
+       }
+
+      /* If we didn't find any A records, change the return code. This can
+      happen when there is a CNAME record but there are no A records for what
+      it points to. */
+
+      cb->rc = DNS_NODATA;
+      }
+      /*FALLTHROUGH*/

 
 

-    /* If we didn't find any A records, change the return code. This can
-    happen when there is a CNAME record but there are no A records for what
-    it points to. */
+    case DNS_NOMATCH:
+    case DNS_NODATA:
+      {
+      /* Although there already is a neg-cache layer maintained by
+      dns_basic_lookup(), we have a dnslist cache entry allocated and
+      tree-inserted. So we may as well use it. */

 
 

-    if (!cb->rhs) cb->rc = DNS_NODATA;
+      time_t soa_negttl = dns_expire_from_soa(dnsa, T_A);
+      cb->expiry = soa_negttl ? soa_negttl : time(NULL) + ttl;
+      break;
+      }
+
+    default:
+      cb->expiry = time(NULL) + ttl;
+      break;

     }
 
     }
 

-  cb->expiry = time(NULL)+ttl;

   store_pool = old_pool;
   store_pool = old_pool;

+  HDEBUG(D_dnsbl) debug_printf("dnslists: wrote cache entry, ttl=%d\n",
+    (int)(cb->expiry - time(NULL)));

   }
 
 /* We now have the result of the DNS lookup, either newly done, or cached
   }
 
 /* We now have the result of the DNS lookup, either newly done, or cached


@@ -3477,7 +3501,7 @@ list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
 
 if (cb->rc == DNS_SUCCEED)
   {
 
 if (cb->rc == DNS_SUCCEED)
   {

-  dns_address *da = NULL;
+  dns_address * da = NULL;

   uschar *addlist = cb->rhs->address;
 
   /* For A and AAAA records, there may be multiple addresses from multiple
   uschar *addlist = cb->rhs->address;
 
   /* For A and AAAA records, there may be multiple addresses from multiple


@@ -3714,7 +3738,7 @@ dns_init(FALSE, FALSE, FALSE);    /*XXX dnssec? */
 
 /* Loop through all the domains supplied, until something matches */
 
 
 /* Loop through all the domains supplied, until something matches */
 

-while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
+while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))

   {
   int rc;
   BOOL bitmask = FALSE;
   {
   int rc;
   BOOL bitmask = FALSE;


@@ -3724,7 +3748,7 @@ while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL
   uschar *iplist;
   uschar *key;
 
   uschar *iplist;
   uschar *key;
 

-  HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
+  HDEBUG(D_dnsbl) debug_printf("dnslists check: %s\n", domain);

 
   /* Deal with special values that change the behaviour on defer */
 
 
   /* Deal with special values that change the behaviour on defer */
 


@@ -3778,8 +3802,7 @@ while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL
   set domain_txt == domain. */
 
   domain_txt = domain;
   set domain_txt == domain. */
 
   domain_txt = domain;

-  comma = Ustrchr(domain, ',');
-  if (comma != NULL)
+  if ((comma = Ustrchr(domain, ',')))

     {
     *comma++ = 0;
     domain = comma;
     {
     *comma++ = 0;
     domain = comma;


@@ -3821,7 +3844,7 @@ while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL
          acl_wherenames[where]);
       return ERROR;
       }
          acl_wherenames[where]);
       return ERROR;
       }

-    if (sender_host_address == NULL) return FAIL;    /* can never match */
+    if (!sender_host_address) return FAIL;    /* can never match */

     if (revadd[0] == 0) invert_address(revadd, sender_host_address);
     rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
       iplist, bitmask, match_type, defer_return);
     if (revadd[0] == 0) invert_address(revadd, sender_host_address);
     rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
       iplist, bitmask, match_type, defer_return);


@@ -3843,11 +3866,9 @@ while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL
     int keysep = 0;
     BOOL defer = FALSE;
     uschar *keydomain;
     int keysep = 0;
     BOOL defer = FALSE;
     uschar *keydomain;

-    uschar keybuffer[256];

     uschar keyrevadd[128];
 
     uschar keyrevadd[128];
 

-    while ((keydomain = string_nextinlist(CUSS &key, &keysep, keybuffer,
-            sizeof(keybuffer))) != NULL)
+    while ((keydomain = string_nextinlist(CUSS &key, &keysep, NULL, 0)))

       {
       uschar *prepend = keydomain;
 
       {
       uschar *prepend = keydomain;
 


@@ -3859,7 +3880,6 @@ while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL
 
       rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
         bitmask, match_type, defer_return);
 
       rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
         bitmask, match_type, defer_return);

-

       if (rc == OK)
         {
         dnslist_domain = string_copy(domain_txt);
       if (rc == OK)
         {
         dnslist_domain = string_copy(domain_txt);