misc fixes

src/fpsgame/ctf.h

@@ -713,6 +713,7 @@ struct ctfclientmode : clientmode
                 dropped = getint(p);
                 if(dropped) loopk(3) droploc[k] = getint(p)/DMF;
             }
+            if(p.overread()) break;
             if(commit && flags.inrange(i))
             {
                 flag &f = flags[i];

src/shared/tools.h

@@ -193,7 +193,7 @@ struct databuf
 
     databuf subbuf(int sz)
     {
-        sz = min(sz, maxlen-len);
+        sz = clamp(sz, 0, maxlen-len);
         len += sz;
         return databuf(&buf[len-sz], sz);
     }