C setgid():不允许操作
我的任务是为系统上的所有用户列出用户所属的所有组。其想法是通过C setgid():不允许操作,c,unix,C,Unix,我的任务是为系统上的所有用户列出用户所属的所有组。其想法是通过/etc/passwd为每个用户打印其组 [编辑]这成功了: if( getgrouplist(passwd->pw_name, passwd->pw_gid, groups, &ngroups) < 0) error_fatal ("getgrouplist ()"); 代码: while((passwd=getpwent())!=NULL){ uid=pass
/etc/passwd
为每个用户打印其组
[编辑]这成功了:
if( getgrouplist(passwd->pw_name, passwd->pw_gid,
groups, &ngroups) < 0)
error_fatal ("getgrouplist ()");
代码:
while((passwd=getpwent())!=NULL){
uid=passwd->pw\u uid;
gid=passwd->pw_gid;
if(setgid(gid)<0)
错误_致命(“setgid()”);
if(setuid(uid)<0)
错误\致命(“setuid()”);
if((ngroups=getgroups(0,NULL))<0)
错误\致命(“getgroups()”);
如果((组=(gid_t*)malloc(sizeof(gid_t)*ngroups))<0
致命错误(“malloc()”);
if(getgroups(ngroups,groups)<0)
错误\致命(“getgroups()”);
printf(“用户%s是:”,passwd->pw_name)的成员);
对于(i=0;i组名称);
}
putchar('\n');
}
有什么想法吗?一旦您的程序调用
setuid()
切换到root
以外的其他用户,您的程序就放弃了切换用户的权限,因此后续调用将失败。一旦您的程序调用setuid()
切换到root
以外的其他用户,您的程序已放弃切换用户的权限,因此后续调用将失败。可能重复的可能重复的哦..所以我知道这不是一个好方法。多谢各位!哦……我明白了,这不是一个好办法。多谢各位!
User root is a member of: root
User daemon is a member of: root
setgid(): Operation not permitted
while ((passwd = getpwent ()) != NULL) {
uid = passwd->pw_uid;
gid = passwd->pw_gid;
if (setgid(gid) < 0)
error_fatal ("setgid()");
if (setuid(uid) < 0)
error_fatal ("setuid()");
if((ngroups = getgroups (0, NULL)) < 0)
error_fatal ("getgroups ()");
if((groups = (gid_t *) malloc (sizeof (gid_t) * ngroups)) < 0)
error_fatal ("malloc ()");
if (getgroups (ngroups, groups) < 0)
error_fatal ("getgroups ()");
printf ("User %s is a member of: ", passwd->pw_name);
for (i = 0; i < ngroups; i++) {
gid = groups[i];
if((group = getgrgid (gid)) == NULL)
error_fatal ("getgrgid ()");
printf ("%s ", group->gr_name);
}
putchar ('\n');
}