%general-entities; ]> shadow &shadow-version;

&shadow-url;

Shadow If you would like to enforce the use of strong passwords, refer to for installing CrackLib prior to building Shadow. Then add --with-libcrack to the configure command below. Disable the installation of the groups program and its man pages, as Coreutils provides a better version. Also, prevent the installation of manual pages that were already installed in : sed -i 's/groups$(EXEEXT) //' src/Makefile.in find man -name Makefile.in -exec sed -i 's/groups\.1 / /' {} \; find man -name Makefile.in -exec sed -i 's/getspnam\.3 / /' {} \; find man -name Makefile.in -exec sed -i 's/passwd\.5 / /' {} \; Instead of using the default crypt method, use the much more secure YESCRYPT method of password encryption, which also allows passwords longer than 8 characters. It is also necessary to change the obsolete /var/spool/mail location for user mailboxes that Shadow uses by default to the /var/mail location used currently. And, remove /bin and /sbin from the PATH, since they are simply symlinks to their counterparts in /usr. If you wish to include /bin and/or /sbin in the PATH for some reason, modify the PATH in .bashrc after LFS has been built. sed -e 's:#ENCRYPT_METHOD DES:ENCRYPT_METHOD YESCRYPT:' \ -e 's:/var/spool/mail:/var/mail:' \ -e '/PATH=/{s@/sbin:@@;s@/bin:@@}' \ -i etc/login.defs If you chose to build Shadow with Cracklib support, issue this command: sed -i 's:DICTPATH.*:DICTPATH\t/lib/cracklib/pw_dict:' etc/login.defs Prepare Shadow for compilation: touch /usr/bin/passwd ./configure --sysconfdir=/etc \ --disable-static \ --with-{b,yes}crypt \ --without-libbsd \ --with-group-name-max-length=32 touch /usr/bin/passwd The file /usr/bin/passwd needs to exist because its location is hardcoded in some programs; if it does not already exist, the installation script will create it in the wrong place. --with-{b,yes}crypt The shell expands this to two switches, --with-bcrypt and --with-yescrypt. They allow shadow to use the Bcrypt and Yescrypt algorithms implemented by Libxcrypt for hashing passwords. These algorithms are more secure (in particular, much more resistant to GPU-based attacks) than the traditional SHA algorithms. --with-group-name-max-length=32 The longest permissible user name is 32 characters. Make the maximum length of a group name the same. --without-libbsd Do not use the readpassphrase function from libbsd which is not in LFS. Use the internal copy instead. Compile the package: make This package does not come with a test suite. Install the package: make exec_prefix=/usr install make -C man install-man Shadow configuring This package contains utilities to add, modify, and delete users and groups; set and change their passwords; and perform other administrative tasks. For a full explanation of what password shadowing means, see the doc/HOWTO file within the unpacked source tree. If you use Shadow support, keep in mind that programs which need to verify passwords (display managers, FTP programs, pop3 daemons, etc.) must be Shadow-compliant. That is, they must be able to work with shadowed passwords. To enable shadowed passwords, run the following command: pwconv To enable shadowed group passwords, run: grpconv Shadow's default configuration for the useradd utility needs some explanation. First, the default action for the useradd utility is to create the user and a group with the same name as the user. By default the user ID (UID) and group ID (GID) numbers will begin at 1000. This means if you don't pass extra parameters to useradd, each user will be a member of a unique group on the system. If this behavior is undesirable, you'll need to pass either the -g or -N parameter to useradd, or else change the setting of USERGROUPS_ENAB in /etc/login.defs. See useradd(8) for more information. Second, to change the default parameters, the file /etc/default/useradd must be created and tailored to suit your particular needs. Create it with: mkdir -p /etc/default useradd -D --gid 999 GROUP=999 This parameter sets the beginning of the group numbers used in the /etc/group file. The particular value 999 comes from the --gid parameter above. You may set it to any desired value. Note that useradd will never reuse a UID or GID. If the number identified in this parameter is used, it will use the next available number. Note also that if you don't have a group with an ID equal to this number on your system, then the first time you use useradd without the -g parameter, an error message will be generated—useradd: unknown GID 999, even though the account has been created correctly. That is why we created the group users with this group ID in . CREATE_MAIL_SPOOL=yes This parameter causes useradd to create a mailbox file for each new user. useradd will assign the group ownership of this file to the mail group with 0660 permissions. If you would rather not create these files, issue the following command: sed -i '/MAIL/s/yes/no/' /etc/default/useradd Choose a password for user root and set it by running: passwd root Installed programs Installed directories Installed libraries chage, chfn, chgpasswd, chpasswd, chsh, expiry, faillog, getsubids, gpasswd, groupadd, groupdel, groupmems, groupmod, grpck, grpconv, grpunconv, login, logoutd, newgidmap, newgrp, newuidmap, newusers, nologin, passwd, pwck, pwconv, pwunconv, sg (link to newgrp), su, useradd, userdel, usermod, vigr (link to vipw), and vipw /etc/default and /usr/include/shadow libsubid.so Short Descriptions chage Used to change the maximum number of days between obligatory password changes chage chfn Used to change a user's full name and other information chfn chgpasswd Used to update group passwords in batch mode chgpasswd chpasswd Used to update user passwords in batch mode chpasswd chsh Used to change a user's default login shell chsh expiry Checks and enforces the current password expiration policy expiry faillog Is used to examine the log of login failures, to set a maximum number of failures before an account is blocked, and to reset the failure count faillog getsubids Is used to list the subordinate id ranges for a user getsubids gpasswd Is used to add and delete members and administrators to groups gpasswd groupadd Creates a group with the given name groupadd groupdel Deletes the group with the given name groupdel groupmems Allows a user to administer his/her own group membership list without the requirement of super user privileges. groupmems groupmod Is used to modify the given group's name or GID groupmod grpck Verifies the integrity of the group files /etc/group and /etc/gshadow grpck grpconv Creates or updates the shadow group file from the normal group file grpconv grpunconv Updates /etc/group from /etc/gshadow and then deletes the latter grpunconv login Is used by the system to let users sign on login logoutd Is a daemon used to enforce restrictions on log-on time and ports logoutd newgidmap Is used to set the gid mapping of a user namespace newgidmap newgrp Is used to change the current GID during a login session newgrp newuidmap Is used to set the uid mapping of a user namespace newuidmap newusers Is used to create or update an entire series of user accounts newusers nologin Displays a message saying an account is not available; it is designed to be used as the default shell for disabled accounts nologin passwd Is used to change the password for a user or group account passwd pwck Verifies the integrity of the password files /etc/passwd and /etc/shadow pwck pwconv Creates or updates the shadow password file from the normal password file pwconv pwunconv Updates /etc/passwd from /etc/shadow and then deletes the latter pwunconv sg Executes a given command while the user's GID is set to that of the given group sg su Runs a shell with substitute user and group IDs su useradd Creates a new user with the given name, or updates the default new-user information useradd userdel Deletes the specified user account userdel usermod Is used to modify the given user's login name, user identification (UID), shell, initial group, home directory, etc. usermod vigr Edits the /etc/group or /etc/gshadow files vigr vipw Edits the /etc/passwd or /etc/shadow files vipw libsubid library to handle subordinate id ranges for users and groups libsubid