????????ūSamba???????????????????????????????????????????Linux???е???????????????????????????????r????д??w??????У?x?????????????????????????????????setuid??setgid??stick bit?????λ????

????1??setuid??setgid????

??????????????????????????/etc/passwd??/usr/bin/passwd?????

[plain] view plaincopy
[root@Salve1 school]# ll /etc/passwd /usr/bin/passwd
-rw-r--r-- 1 root root  2005 Apr 23 01:25 /etc/passwd
-rwsr-xr-x 1 root root 23420 Aug 11  2010 /usr/bin/passwd
[root@Salve1 school]#

??????????￡?/etc/passwd?????? -rw-r--r-- ?????????????????????ж?д??????????????????????????в??????????????????????????????????????????root???????????????????/usr/bin/passwd   someuser???????????????/etc/passwd????????root?????????ж?/etc/passwd??д??????????????????????????????setuid??setuid????????“????и?????????????????????????????”?????????????passwd??????root?????????????????/etc/passwd??????????????????s?????????x??????????-rwsr-xr-x ????setgid???????????????????????????????????????????????????С?

????2??stick bit?????λ??

??????????????????????????/tmp?????

[plain] view plaincopy
[root@Salve1 /]# ll -d /tmp
drwxrwxrwt 13 root root 4096 Apr 23 02:06 /tmp
[root@Salve1 /]#

???????????/tmp???????????????????е?????????????????е???????????????????????????????????????????????A??????′????????????????B???????????????????????????????????????????????????stick bit?????λ??????????????????????????????????stick bit?????λ??????????μ????????????????????root???????????????/tmp???μ?stuff????????????????????????????λ?????á?

????3????????????????????

chmod u+s  xxx    # ????setuid???
chmod g+s  xxx    # ????setgid???
chmod o+t   xxx   # ????stick bit?????????
chmod  4775  xxx  # ????setuid???
chmod  2775  xxx  # ????setgid???
chmod  1775  xxx  # ????stick bit?????????

????4????????????????s??t ????????????????S??T??????????????λ????????и???x??????У???????????????????????????????Ч?????????????????x????????????s??t ??????