CF: goto directory fix

[Jan Echternach <echter@informatik.uni-rostock.de>]

Hi,

A dungeon master could crash the server by trying to 'goto' to a
directory.

The patch fixes check_path() and also adds another check in
open_and_uncompress() that can't be fooled by race conditions.

-- 
Jan
diff -rc orig/crossfire-0.95.5-patch8/common/map.c crossfire-0.95.5/common/map.c
*** orig/crossfire-0.95.5-patch8/common/map.c	Wed Mar 22 08:56:47 2000
--- crossfire-0.95.5/common/map.c	Thu Apr 13 16:13:45 2000
***************
*** 183,189 ****
      if (i == NROF_COMPRESS_METHODS)
        return (-1);
      if (!S_ISREG (statbuf.st_mode))
! 	return (0);
  
      if (((statbuf.st_mode & S_IRGRP) && getegid() == statbuf.st_gid) ||
  	((statbuf.st_mode & S_IRUSR) && geteuid() == statbuf.st_uid) ||
--- 183,189 ----
      if (i == NROF_COMPRESS_METHODS)
        return (-1);
      if (!S_ISREG (statbuf.st_mode))
! 	return (-1);
  
      if (((statbuf.st_mode & S_IRGRP) && getegid() == statbuf.st_gid) ||
  	((statbuf.st_mode & S_IRUSR) && geteuid() == statbuf.st_uid) ||
***************
*** 504,511 ****
        }
        if ((fp = popen(buf2, "r")) != NULL)
          return fp;
!     } else if((fp=fopen(name,"r"))!=NULL)
        return fp;
    }
    LOG(llevDebug, "Can't open %s\n", name);
    return NULL;
--- 504,519 ----
        }
        if ((fp = popen(buf2, "r")) != NULL)
          return fp;
!     } else if((fp=fopen(name,"r"))!=NULL) {
!       struct stat statbuf;
!       if (fstat (fileno (fp), &statbuf) || ! S_ISREG (statbuf.st_mode)) {
!         LOG (llevDebug, "Can't open %s - not a regular file\n", name);
!         (void) fclose (fp);
!         errno = EISDIR;
!         return NULL;
!       }
        return fp;
+     }
    }
    LOG(llevDebug, "Can't open %s\n", name);
    return NULL;