diff options
Diffstat (limited to 'man/passwd.1.xml')
| -rw-r--r-- | man/passwd.1.xml | 73 |
1 files changed, 52 insertions, 21 deletions
diff --git a/man/passwd.1.xml b/man/passwd.1.xml index 52b8637..506b134 100644 --- a/man/passwd.1.xml +++ b/man/passwd.1.xml @@ -6,6 +6,7 @@ --> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ +<!ENTITY BCRYPT_MIN_ROUNDS SYSTEM "login.defs.d/BCRYPT_MIN_ROUNDS.xml"> <!ENTITY ENCRYPT_METHOD SYSTEM "login.defs.d/ENCRYPT_METHOD.xml"> <!ENTITY MD5_CRYPT_ENAB SYSTEM "login.defs.d/MD5_CRYPT_ENAB.xml"> <!ENTITY OBSCURE_CHECKS_ENAB SYSTEM "login.defs.d/OBSCURE_CHECKS_ENAB.xml"> @@ -13,6 +14,7 @@ <!ENTITY PASS_CHANGE_TRIES SYSTEM "login.defs.d/PASS_CHANGE_TRIES.xml"> <!ENTITY PASS_MAX_LEN SYSTEM "login.defs.d/PASS_MAX_LEN.xml"> <!ENTITY SHA_CRYPT_MIN_ROUNDS SYSTEM "login.defs.d/SHA_CRYPT_MIN_ROUNDS.xml"> +<!ENTITY YESCRYPT_COST_FACTOR SYSTEM "login.defs.d/YESCRYPT_COST_FACTOR.xml"> <!-- SHADOW-CONFIG-HERE --> ]> <refentry id='passwd.1'> @@ -94,27 +96,10 @@ </para> <para> - Then, the password is tested for complexity. As a general guideline, - passwords should consist of 6 to 8 characters including one or more - characters from each of the following sets: - </para> - - <itemizedlist mark='bullet'> - <listitem> - <para>lower case alphabetics</para> - </listitem> - <listitem> - <para>digits 0 thru 9</para> - </listitem> - <listitem> - <para>punctuation marks</para> - </listitem> - </itemizedlist> - - <para> - Care must be taken not to include the system default erase or kill - characters. <command>passwd</command> will reject any password which - is not suitably complex. + Then, the password is tested for complexity. + <command>passwd</command> will reject any password which is not + suitably complex. Care must be taken not to include the system + default erase or kill characters. </para> </refsect2> @@ -140,6 +125,17 @@ </para> <para> + As a general guideline, passwords should be long and random. It's + fine to use simple character sets, such as passwords consisting + only of lowercase letters, if that helps memorizing longer + passwords. For a password consisting only of lowercase English + letters randomly chosen, and a length of 32, there are 26^32 + (approximately 2^150) different possible combinations. Being an + exponential equation, it's apparent that the exponent (the length) + is more important than the base (the size of the character set). + </para> + + <para> You can find advice on how to choose a strong password on http://en.wikipedia.org/wiki/Password_strength </para> @@ -288,6 +284,21 @@ </varlistentry> <varlistentry> <term> + <option>-P</option>, <option>--prefix</option> <replaceable>PREFIX_DIR</replaceable> + </term> + <listitem> + <para> + Apply changes to configuration files under the root filesystem + found under the directory <replaceable>PREFIX_DIR</replaceable>. + This option does not chroot and is intended for preparing a cross-compilation + target. Some limitations: NIS and LDAP users/groups are + not verified. PAM authentication is using the host files. + No SELINUX support. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> <option>-S</option>, <option>--status</option> </term> <listitem> @@ -347,6 +358,17 @@ </para> </listitem> </varlistentry> + <varlistentry> + <term> + <option>-s</option>, <option>--stdin</option> + </term> + <listitem> + <para> + This option is used to indicate that passwd should read the new password from standard + input, which can be a pipe. + </para> + </listitem> + </varlistentry> </variablelist> </refsect1> @@ -474,6 +496,9 @@ <refentrytitle>chpasswd</refentrytitle><manvolnum>8</manvolnum> </citerefentry>, <citerefentry> + <refentrytitle>makepasswd</refentrytitle><manvolnum>1</manvolnum> + </citerefentry>, + <citerefentry> <refentrytitle>passwd</refentrytitle><manvolnum>5</manvolnum> </citerefentry>, <citerefentry> @@ -488,5 +513,11 @@ <refentrytitle>usermod</refentrytitle><manvolnum>8</manvolnum> </citerefentry>. </para> + + <para> + The following web page comically (yet correctly) compares the + strength of two different methods for choosing a password: + "https://xkcd.com/936/" + </para> </refsect1> </refentry> |