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>
This commit is contained in:
Scott Rifenbark 2014-06-02 10:39:00 +03:00 committed by Richard Purdie
parent e891596f93
commit a3b8282d25
1 changed files with 31 additions and 47 deletions

View File

@ -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>
@ -4009,38 +4008,34 @@ 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
@ -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>