dev-manual: Edits to the "Making Images More Secure" section.

Fixes [YOCTO #5482]

I applied some review edits as directed by Paul Eggleton. The
main feature was to merge the information on setting root
and extra user's passwords.  Also, permanently removed the
reference to the wiki that showed the less optimal way of
setting a root password.

(From yocto-docs rev: fef0e17cd3835580abed175ef4a7baf22b9b7673)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 31 insertions, 47 deletions

diff --git a/documentation/dev-manual/dev-manual-common-tasks.xml b/documentation/dev-manual/dev-manual-common-tasks.xml
index dffba96e7d..72551fb7ab 100644
--- a/documentation/dev-manual/dev-manual-common-tasks.xml
+++ b/documentation/dev-manual/dev-manual-common-tasks.xml
@@ -3841,7 +3841,7 @@
         <title>Making Images More Secure</title>
 
         <para>
-            Security for a device is always a concern.
+            Security is of increasing concern for embedded devices.
             Consider the issues and problems discussed in just this
             sampling of work found across the Internet:
             <itemizedlist>
@@ -3872,15 +3872,14 @@ Gateways via their Web Interfaces</ulink>"</emphasis>
             image secure.
             Consequently, this section provides some guidance and suggestions
             for consideration when you want to make your image more secure.
-        </para>
-
-        <para>
-            Because the security requirements and risks are
-            different for every type of device, this section cannot
-            provide a complete reference on securing your custom OS.
-            It is strongly recommended that you also consult other sources
-            of information on embedded Linux system hardening and on
-            security.
+            <note>
+                Because the security requirements and risks are
+                different for every type of device, this section cannot
+                provide a complete reference on securing your custom OS.
+                It is strongly recommended that you also consult other sources
+                of information on embedded Linux system hardening and on
+                security.
+            </note>
         </para>
 
         <section id='general-considerations'>
@@ -3928,7 +3927,7 @@ Gateways via their Web Interfaces</ulink>"</emphasis>
                         Ensure you remove or disable debugging functionality
                         before producing the final image.
                         For information on how to do this, see the
-                        "<link linkend='considerations-specific-to-the-openembedded-build-system'>Considerations Specific to the OpenEmbedded Build System</link>
+                        "<link linkend='considerations-specific-to-the-openembedded-build-system'>Considerations Specific to the OpenEmbedded Build System</link>"
                         section.
                         </para></listitem>
                     <listitem><para>
@@ -4009,39 +4008,35 @@ Gateways via their Web Interfaces</ulink>"</emphasis>
                         during production.
                         </para></listitem>
                     <listitem><para>
-                        It is possible to set a root password for the image.
-                        When you set up root passwords for multiple images,
-                        you should not duplicate them.
-                        See the note on passwords at the end of this list.
+                        It is possible to set a root password for the image
+                        and also to set passwords for any extra users you might
+                        add (e.g. administrative or service type users).
+                        When you set up passwords for multiple images or
+                        users, you should not duplicate passwords.
                         </para>
                         <para>
-                        To set up a root password,
-                        use the <filename>extrausers</filename>
-                        class, which is the preferred method.
-                        For an example on how to set up the root password,
-                        see the
+                        To set up passwords, use the
+                        <filename>extrausers</filename> class, which is the
+                        preferred method.
+                        For an example on how to set up both root and user
+                        passwords, see the
                         "<ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-extrausers'><filename>extrausers.bbclass</filename></ulink>"
                         section.
                         <note>
-                            You can also see the the example in the
-                            <ulink url='https://wiki.yoctoproject.org/wiki/FAQ:How_do_I_set_or_change_the_root_password'>How do I set or change the root password Wiki</ulink>
-                            page as an alternative method.
+                            When adding extra user accounts or setting a
+                            root password, be cautious about setting the
+                            same password on every device.
+                            If you do this, and the password you have set
+                            is exposed, then every device is now potentially
+                            compromised.
+                            If you need this access but want to ensure
+                            security, consider setting a different,
+                            random password for each device.
+                            Typically, you do this as a separate step after
+                            you deploy the image onto the device.
                         </note>
                         </para></listitem>
                     <listitem><para>
-                        It is possible to add an additional user account
-                        for later administrative or service access.
-                        As with root passwords, be sure to not duplicate
-                        passwords for generic users (e.g. tester, qa, and
-                        so forth) across multiple devices.
-                        See the note on passwords following this list.
-                        </para>
-                        <para>
-                        As with the root password, you also use the
-                        <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-extrausers'><filename>extrausers</filename></ulink>
-                        class.
-                        </para></listitem>
-                    <listitem><para>
                         Consider enabling a Mandatory Access Control (MAC)
                         framework (such as SMACK or SELinux) and tuning it
                         appropriately for your device's usage.
@@ -4050,17 +4045,6 @@ Gateways via their Web Interfaces</ulink>"</emphasis>
             </para>
 
             <para>
-                <note><title>A Note about Passwords</title>
-                    When adding extra user accounts or deciding on root
-                    passwords for multiple devices, be cautious about setting
-                    the same passwords for multiple users or devices.
-                    If you want the device to remain secure from unauthorized
-                    access, and the password set on all devices becomes
-                    compromised, then every device becomes compromised.
-                    If you need this access but want to ensure security,
-                    consider setting a different, random passwords for each
-                    user or device.
-                </note>
             </para>
         </section>