DO NOT USE THE PACKAGES IN THIS SECTION, THEY HAVE SECURITY PROBLEMS
The original Shadow Suite was written by John F. Haugh II.
There are several versions that have been used on Linux systems:
shadow-3.3.1 is the original.shadow-3.3.1-2 is Linux specific patch made by
Florian La Roche <flla@stud.uni-sb.de> and contains some further
enhancements.shadow-mk was specifically packaged for Linux.The shadow-mk package contains the shadow-3.3.1 package
distributed by John F. Haugh II with the shadow-3.3.1-2 patch
installed, a few fixes made by
Mohan Kokal <magnus@texas.net>
that make installation a lot easier, a patch by Joseph R.M. Zbiciak
for login1.c (login.secure) that eliminates the -f, -h security
holes in /bin/login, and some other miscellaneous patches.
The shadow.mk package was the previously recommended
package, but should be replaced due to a security problem with the
login program.
There are security problems with Shadow versions 3.3.1, 3.3.1-2,
and shadow-mk involving the login program. This login bug
involves not checking the length of a login name. This causes the buffer to
overflow causing crashes or worse. It has been rumored that this buffer
overflow can allow someone with an account on the system to use this bug and
the shared libraries to gain root access. I won't discuss exactly
how this is possible because there are a lot of Linux systems that are
affected, but systems with these Shadow Suites installed, and
most pre-ELF distributions without the Shadow Suite
are vulnerable!
For more information on this and other Linux security issues, see the Linux Security home page (Shared Libraries and login Program Vulnerability)
目前建议 Shadow Suite 版本目前还是 BETA 测试版，然后，最近版本在生产环境
是安全的且没有包含易受攻击的 签入(login) 程序。
该套件(package)使用惯例命名为：
shadow-YYMMDD.tar.gz
YYMMDD 是Suite 的发行日期。
目前 BETA 测试版本是 Version 3.3.3 ，且由 Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl> 维护。
还可以从该处得到： shadow-current.tar.gz.
下列网站也可以找到相关信息：
你应该可以获得目前最新的版本。
你应该不要是用比 shadow-960129 更旧版本，因为它们有 签入
的安全问题。
于参考资料方面，我用 shadow-960129 档进行安装介绍。
如果你之前使用 shadow-mk ，你应该更信这个版本且重建编译。
Shadow Suite 包括对下列功能之替代程序：
su, login, passwd, newgrp, chfn, chsh, and id
该套件还包括新程序：
chage, newusers, dpasswd, gpasswd, useradd, userdel, usermod, groupadd,
groupdel, groupmod, groups, pwck, grpck, lastlog, pwconv, and pwunconv
除此之外，函式库： libshadow.a 也包括需要存取使用者密码之写和编译程序。
程序之操作手册也包含在其中。
也有对签入程序的 configuration file ，它将被安装在 /etc/login.defs 档。