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#include
#include
uid_t getuid(void);
uid_t geteuid(void);
gid_t getgid (void);
gid_t getegid (void);
int setuid (uid_t UID);
int setruid (uid_t RUID);
int seteuid (uid_t EUID);
int setreuid (uid_t RUID,uid_t EUID);
int setgid (gid_t GID);
int setrgid (gid_t RGID);
int setegid (git_t EGID);
int setregid (gid_t RGID, gid_t EGID);
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SUID/SGID :
¼ÙÈçÄãÓÐÎļþa.txt
#ls -l a.txt
-rwxrwxrwx
#chmod 4777 a.txt
-rwsrwxrwx ======>×¢ÒâsλÖÃ
#chmod 2777 a.txt
-rwxrwsrwx ======>×¢ÒâsλÖÃ
#chmod 7777 a.txt
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ÏÖÔÚÔÙ¿´Ç°ÃæÉèÖà SUID/SGID×÷ÓÃ:
#cd /sbin
#./lsusb
...
#su aaa(ÆÕͨÓû§)
$./lsusb
...
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$su
#chmod 4755 lsusb
#su aaa
$./lsusb
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Why we need suid,how do we use suid?
r -- ¶Á·ÃÎÊ
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#ls -l /etc/passwd
-rw-r--r-- 1 root root 2520 Jul 12 18:25 passwd
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[root@sgrid5 bin]# ls -l passwd
-r-s--s--x 1 root root 16336 Feb 14 2003 passwd
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[root@sgrid5 bin]#chmod u-s /bin/ping
[root@sgrid5 bin]# ls -l ping
-rwxr-xr-x 1 root root 28628 Jan 25 2003 ping
[root@sgrid5 bin]#su test
[test@sgrid5 bin]$ ping byhh.net
ping: icmp open socket: Operation not permitted
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