Doc-patch: PAM authentication fails for local UNIX users

On Tue, Dec 18, 2007 at 12:41:56PM +0530, Dhanaraj M wrote:

Hi all,

This is the continuation to the discussion that we had in the hacker's
list.
http://archives.postgresql.org/pgsql-hackers/2007-08/msg00684.php

Here, I like to add some details in 20.2.6. PAM authentication section.
http://www.postgresql.org/docs/8.2/interactive/auth-methods.html#AUTH-PAM

Can someone review and make changes, if required? Thanks.

Eh, those extensions are only valid if you use PAM with a shadow password
file, no? You shouldn't need root if you use say PAM-with-LDAP?

//Magnus

Magnus Hagander wrote:

On Tue, Dec 18, 2007 at 12:41:56PM +0530, Dhanaraj M wrote:

Hi all,

This is the continuation to the discussion that we had in the hacker's
list.
http://archives.postgresql.org/pgsql-hackers/2007-08/msg00684.php

Here, I like to add some details in 20.2.6. PAM authentication section.
http://www.postgresql.org/docs/8.2/interactive/auth-methods.html#AUTH-PAM

Can someone review and make changes, if required? Thanks.

Eh, those extensions are only valid if you use PAM with a shadow password
file, no? You shouldn't need root if you use say PAM-with-LDAP?

Also, it strikes me that granting the postgres user read access to the
shadow file is probably very poor security practice, and not something I
would want to recommend without considerable thought. What we should
say, rather, is that PAM auth is likely to fail if your PAM is set up to
use the shadow file rather than an auth source such as LDAP which does
not require privileged file access.

cheers

andrew

This is the continuation to the discussion that we had in the
hacker's list.
http://archives.postgresql.org/pgsql-hackers/2007-08/msg00684.php

Here, I like to add some details in 20.2.6. PAM authentication section.
http://www.postgresql.org/docs/8.2/interactive/auth-methods.html#AUTH-PAM

Can someone review and make changes, if required? Thanks.

Eh, those extensions are only valid if you use PAM with a shadow
password
file, no? You shouldn't need root if you use say PAM-with-LDAP?

Also, it strikes me that granting the postgres user read access to the
shadow file is probably very poor security practice, and not something
I would want to recommend without considerable thought. What we should
say, rather, is that PAM auth is likely to fail if your PAM is set up
to use the shadow file rather than an auth source such as LDAP which
does not require privileged file access.

Is this change Ok?

*** client-auth.sgml.orig       Tue Aug 21 16:52:45 2007
--- client-auth.sgml    Tue Aug 21 17:02:52 2007
***************
*** 987,992 ****
--- 987,1001 ----
    and the <ulink url="http://www.sun.com/software/solaris/pam/">
    <systemitem class="osname">Solaris</> PAM Page</ulink>.
   </para>
+
+    <note>
+     <para>
+      If your PAM is set up to use the shadow file, the PAM authentication
+      is likely to fail for local UNIX users because the postgresql server
+      is started by a non-root user. However, this is not an issue
+      when LDAP or other authentication mechanism is used.
+     </para>
+    </note>
  </sect2>
 </sect1>

I have updated the documentation to read:

If PAM is set up to read <filename>/etc/shadow</>, authentication
will fail because the PostgreSQL server is started by a non-root
user. However, this is not an issue with LDAP or other authentication
methods.

Thanks.

---------------------------------------------------------------------------

Dhanaraj M wrote:

This is the continuation to the discussion that we had in the
hacker's list.
http://archives.postgresql.org/pgsql-hackers/2007-08/msg00684.php

Here, I like to add some details in 20.2.6. PAM authentication section.
http://www.postgresql.org/docs/8.2/interactive/auth-methods.html#AUTH-PAM

Can someone review and make changes, if required? Thanks.

Eh, those extensions are only valid if you use PAM with a shadow
password
file, no? You shouldn't need root if you use say PAM-with-LDAP?

Also, it strikes me that granting the postgres user read access to the
shadow file is probably very poor security practice, and not something
I would want to recommend without considerable thought. What we should
say, rather, is that PAM auth is likely to fail if your PAM is set up
to use the shadow file rather than an auth source such as LDAP which
does not require privileged file access.

Is this change Ok?

*** client-auth.sgml.orig       Tue Aug 21 16:52:45 2007
--- client-auth.sgml    Tue Aug 21 17:02:52 2007
***************
*** 987,992 ****
--- 987,1001 ----
and the <ulink url="http://www.sun.com/software/solaris/pam/">
<systemitem class="osname">Solaris</> PAM Page</ulink>.
</para>
+
+    <note>
+     <para>
+      If your PAM is set up to use the shadow file, the PAM authentication
+      is likely to fail for local UNIX users because the postgresql server
+      is started by a non-root user. However, this is not an issue
+      when LDAP or other authentication mechanism is used.
+     </para>
+    </note>
</sect2>
</sect1>

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