Re: /lib/ld-2.2.4.so

From: Birger Toedtmann (birgerat_private)
Date: Mon Apr 22 2002 - 23:37:34 PDT

  • Next message: Michal Podsedník: "Re: /lib/ld-2.2.4.so"

    Sabau Daniel schrieb am Mon, Apr 22, 2002 at 09:43:32AM +0300:
    > or:
    > lrwxrwxrwx    1 root     root           11 Apr 15 12:01 /lib/ld-linux.so.2 
    > -> ld-2.2.4.so
    > 
    > 	This file gives users the ability of running binaries on witch the 
    > user doesn't have the permission to execute, it is enough to have read 
    > ability on the file in order to execute it:
    > 
    > -rwxr-xr--    1 root     root        45948 Aug  9  2001 /bin/ls
    > 
    > but using the /lib/ld-2.2.4.so file i can execute the ls command:
    > 
    > [08:51:36][draven@Zero:~]:$/lib/ld-2.2.4.so /bin/ls /
    > bin   bzImage   bzImage3  bzImage5  dev  home    lib   mnt  proc  sbin  
    > usr
    > boot  bzImage2  bzImage4  bzImage6  etc  initrd  misc  opt  root  tmp   
    > var
    > 
    > i do not have root preveleges on this account:
    > 
    > [08:51:38][draven@Zero:~]:$id
    > uid=1000(draven) gid=10(wheel) groups=10(wheel),16(trust)
    
    
    I cannot reproduce this behaviour:
    
      # id
      uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel)
    
      # ls -l /bin/ls
      -rwxr-x---    2 root     root        45948 Aug  9  2001 /bin/ls
    
      # exit
      $ id
      uid=500(birger) gid=500(birger) groups=500(birger)
    
      $ ls
      bash: /bin/ls: Permission denied
    
      $ /lib/ld-2.2.4.so /bin/ls
      /bin/ls: error while loading shared libraries: /bin/ls: cannot open shared object file: Permission denied
    
      $ uname -r
      2.4.18
    
      $ cat /etc/redhat-release 
      Red Hat Linux release 7.2 (Enigma)
    
    
    So it has either something to do with the groups you're in (wheel?)
    or grsececurity is doing something weird to your kernel - or its
    both ;-)   - which means, no, I don't have grsecurity in my kernel
    setup.  And be sure /lib/ld-2.2.4.so has no "s" bit set somewhere,
    the default is 755.
    
    
    Regards,
    
    Birger
    



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