How come I, as a normal user, am able to change ownership of a file?

I have a partition that's NFS-mounted from a Netapp SAN. I can create files in that partition, and I can chown those files to another user, any user, even root. How am I able to do so? I thought the kernel would prevent such a thing. I have done this again and again today, using multiple user IDs on the file. I cannot do this in /tmp or in my home directory, which is locally-mounted. I've never seen this behaviour before. Also, I note that setcap/getcap are not found on this machine. I have checked my shell's capabilities and they are all 0's: $ echo $$ 15007 $ cat /proc/15007/task/15007/status Name: bash State: S (sleeping) SleepAVG: 98% Tgid: 15007 Pid: 15007 PPid: 14988 TracerPid: 0 Uid: 71579 71579 71579 71579 Gid: 10000 10000 10000 10000 FDSize: 256 Groups: 9000 10000 10001 10013 10018 10420 24611 36021 ... CapInh: 0000000000000000 CapPrm: 0000000000000000 CapEff: 0000000000000000 I am on a Red Hat 5.3 virtual machine: $ cat /etc/redhat-release Red Hat Enterprise Linux Server release 5.3 (Tikanga) Running an old kernel: $ uname -r 2.6.18-274.7.1.el5 The NFS mount uses defaults: $ cat /etc/fstab ... mynetapp00:/home /mnt/home nfs defaults 0 0 For user authentication, we're using Windows Active Directory with ldap on the Linux side: $ grep passwd /etc/nsswitch.conf passwd: files ldap I'm able to do anthing as sudo: User mikes may run the following commands on this host: (ALL) ALL because I'm one of the ADMINS (contents of /etc/sudoers): User_Alias ADMINS = fred, tom, mikes ADMINS ALL=(ALL) ALL ...But I don't know how that's germaine, because sudo isn't involved. In any event, I was able to create a file and give it my ownership as a user "john" who's not found in /etc/sudoers: # grep john /etc/sudoers # su - john $ touch /mnt/home/blah $ chown mikes /mnt/home/blah $ ls -l /mnt/home/blah -rwxrwxrwx 1 mikes DomainUsers 0 Oct 23 19:45 /mnt/home/blah ...and chown is not aliased (but we knew that, because if chown was an alias or some other program, then I would be able to change ownership in /tmp too): $ alias alias l.='ls -d .* --color=tty' alias ll='ls -l --color=tty' alias ls='ls --color=tty' alias vi='vim' alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde' $ which chown /bin/chown P.S. I'm not kidding: $ id uid=71579(mikes) gid=10000(DomainUsers) $ touch /mnt/home/blah $ chown john /mnt/home/blah $ ls -l /mnt/home/blah -rwxrwxrwx 1 john DomainUsers 0 Oct 23 19:04 /mnt/home/blah $ id john uid=37554(john) gid=10000(DomainUsers) $ chmod 755 /mnt/home/blah chmod: changing permissions of `/mnt/home/blah': Operation not permitted $ rm /mnt/home/blah $ ls -l /mnt/home/blah ls: /mnt/home/blah: No such file or directory $ touch /tmp/blah $ chown john /tmp/blah chown: changing ownership of `/tmp/blah': Operation not permitted