The Shadow package contains programs for handling passwords in a secure way. &buildtime; &shadow-time; &diskspace; &shadow-compsize; &aa-shadow-down; &aa-shadow-dep;   Shadow hard-wires the path to the passwd binary within the binary itself, but does this the wrong way. If a passwd binary is not present before installing Shadow, the package incorrectly assumes it is going to be located at /bin/passwd, but then installs it in /usr/bin/passwd. This will lead to errors about not finding /bin/passwd. To work around this bug, create a dummy passwd file, so that it gets hard-wired properly: touch /usr/bin/passwd Now prepare Shadow for compilation: ./configure --libdir=/usr/lib --enable-shared Work around a problem that prevents Shadow's internationalization from working: echo '#define HAVE_SETLOCALE 1' >> config.h Compile the package: make And install it: make install Shadow uses two files to configure authentication settings for the system. Install these two config files: cp etc/{limits,login.access} /etc We want to change the password method to enable MD5 passwords which are theoretically more secure than the default crypt method and also allow password lengths greater than 8 characters. We also need to change the old /var/spool/mail location for user mailboxes to the current location at /var/mail. We do this by changing the relevant configuration file while copying it to its destination: sed -e 's%/var/spool/mail%/var/mail%' \     -e 's%#MD5_CRYPT_ENAB.no%MD5_CRYPT_ENAB yes%' \     etc/login.defs.linux > /etc/login.defs Be extra careful when typing all of the above. It is probably safer to cut-and-paste it rather than try and type it all in. Move some misplaced symlinks to their proper locations: mv /bin/sg /usr/bin mv /bin/vigr /usr/sbin And move Shadow's dynamic libraries to a more appropriate location: mv /usr/lib/lib{shadow,misc}.so.0* /lib As some packages expect to find the just-moved libraries in /usr/lib, create the following symlinks: ln -sf ../../lib/libshadow.so.0 /usr/lib/libshadow.so ln -sf ../../lib/libmisc.so.0 /usr/lib/libmisc.so The -D option of the useradd program requires this directory for it to work properly: mkdir /etc/default Coreutils has already installed a better groups program in /usr/bin. Remove the one installed by Shadow: rm /bin/groups   This package contains utilities to modify users' passwords, add or delete users and groups, and the like. We're not going to explain what 'password shadowing' means. A full explanation can be found in the doc/HOWTO file within the unpacked Shadow source tree. There's one thing to keep in mind if you decide to use Shadow support: programs that need to verify passwords (for example xdm, ftp daemons, pop3 daemons) need to be 'shadow-compliant', that is they need to be able to work with shadowed passwords. To enable shadowed passwords, run the following command: /usr/sbin/pwconv And to enable shadowed group passwords, run the following command: /usr/sbin/grpconv Under normal circumstances, you won't have created any passwords yet. However, if returning to this section to enable shadowing, you should reset any current user passwords with the passwd command or any group passwords with the gpasswd command. Choose a password for user root and set it via: passwd root &aa-shadow-shortdesc; &aa-shadow-desc;