dirmngr: Do not use MAXDNAME.

* dirmngr/dns-stuff.c (getsrv): Replace MAXDNAME.
* dirmngr/dns-stuff.h (MAXDNAME): Remove.
(struct srventry): Use a fixed value instead of MAXDNAME.
* dirmngr/http.c (connect_server): Use DIMof instead of MAXDNAME.
Malloc a helper array.

--

Depending on the order of included headers it might be that we allocate
the array with a different size than what we test against in another
module.  To make it more robust we use the actual known size of
checking.

A better would be to use a linked list and avoid these large arrays.

Signed-off-by: Werner Koch <wk@gnupg.org>

dirmngr/dns-stuff.c

@@ -651,7 +651,7 @@ getsrv (const char *name,struct srventry **list)
         struct srventry *srv = NULL;
         struct srventry *newlist;
 
-        if (strlen (answer->rrs.srvha[count].ha.host) >= MAXDNAME)
+        if (strlen (answer->rrs.srvha[count].ha.host) >= sizeof srv->target)
           {
             log_info ("hostname in SRV record too long - skipped\n");
             continue;
@@ -747,7 +747,7 @@ getsrv (const char *name,struct srventry **list)
         /* Get the name.  2782 doesn't allow name compression, but
            dn_expand still works to pull the name out of the
            packet. */
-        rc = dn_expand(answer,emsg,pt,srv->target,MAXDNAME);
+        rc = dn_expand(answer,emsg,pt,srv->target, sizeof srv->target);
         if (rc == 1 && srv->target[0] == 0) /* "." */
           {
             xfree(*list);

dirmngr/dns-stuff.h

@@ -71,18 +71,13 @@ struct dns_addrinfo_s
 };
 
 
-
-#ifndef MAXDNAME
-#define MAXDNAME 1025
-#endif
-
 struct srventry
 {
   unsigned short priority;
   unsigned short weight;
   unsigned short port;
   int run_count;
-  char target[MAXDNAME];
+  char target[1025];
 };
 
 

dirmngr/http.c

@@ -2251,13 +2251,23 @@ connect_server (const char *server, unsigned short port,
   if (srvtag)
     {
       /* We're using SRV, so append the tags. */
-      if (1+strlen (srvtag) + 6 + strlen (server) + 1 <= MAXDNAME)
+      if (1 + strlen (srvtag) + 6 + strlen (server) + 1
+          <= DIMof (struct srventry, target))
 	{
-	  char srvname[MAXDNAME];
+	  char *srvname = xtrymalloc (DIMof (struct srventry, target));
 
-	  stpcpy (stpcpy (stpcpy (stpcpy (srvname,"_"), srvtag),
+          if (!srvname) /* Out of core */
-                           "._tcp."), server);
+            {
-	  srvcount = getsrv (srvname, &serverlist);
+              serverlist = NULL;
+              srvcount = 0;
+            }
+          else
+            {
+              stpcpy (stpcpy (stpcpy (stpcpy (srvname,"_"), srvtag),
+                              "._tcp."), server);
+              srvcount = getsrv (srvname, &serverlist);
+              xfree (srvname);
+            }
 	}
     }
 #else
@@ -2273,8 +2283,8 @@ connect_server (const char *server, unsigned short port,
       if (!serverlist)
         return -1; /* Out of core.  */
       serverlist->port = port;
-      strncpy (serverlist->target, server, MAXDNAME);
+      strncpy (serverlist->target, server, DIMof (struct srventry, target));
-      serverlist->target[MAXDNAME-1] = '\0';
+      serverlist->target[DIMof (struct srventry, target)-1] = '\0';
       srvcount = 1;
     }