[sudo-users] sudo su fails with sudo: setreuid(ROOT_UID, user_uid): Operation not permitted

[ben thielsen]

>> sudo su
> sudo: setreuid(ROOT_UID, user_uid): Operation not permitted

some additional information:

for the sake of testing, i've tried a few different variations of  
compiling sudo from source, with the following results:

./configure (with no options):
sudo: setresuid(user_uid, user_uid, ROOT_UID): Operation not permitted

./configure --disable-setresuid:
sudo: setreuid(ROOT_UID, user_uid): Operation not permitted

./configure --disable-setresuid --disable-setreuid
sudo: seteuid(ROOT_UID): Operation not permitted

also:
 >uname -r
2.6.30-1-686

-ben