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Re: (ITS#8485) [PATCH] Adding support for encrypted server private keys
- To: openldap-its@OpenLDAP.org
- Subject: Re: (ITS#8485) [PATCH] Adding support for encrypted server private keys
- From: ahnolds@gmail.com
- Date: Tue, 29 Aug 2017 01:53:30 +0000
- Auto-submitted: auto-generated (OpenLDAP-ITS)
--94eb2c0477b011a5720557daad8c
Content-Type: text/plain; charset="UTF-8"
I take it that this enhancement on the client side API isn't something you
think would be useful. If that's the case, feel free to close this ticket,
and best of luck with your ongoing development!
On Wed, Feb 22, 2017 at 8:49 PM, Alec C <ahnolds@gmail.com> wrote:
> I completely agree that this doesn't add any security when running slapd.
> However, when I originally wrote this patch, I was more targeting API
> usage, and in particular, client-side API usage. My goal was to allow a
> user to present an encrypted key (stored on disk) and a password (only held
> in memory), and use these to query a secure LDAP server. The issue of how
> the password got into memory is certainly beyond the scope of OpenLDAP in
> this case, but it certainly could be done securely in a way that wouldn't
> leave it exposed to a third-party with file-system access.
>
> For example (in the use case that motivated me originally), an sysadmin
> could input the password through an online form, submit said form to a
> Python webserver over HTTPS, the Python code could pass the password to
> OpenLDAP through a Python interface like python-ldap (
> https://www.python-ldap.org/), and then use the LDAPS or STARTTLS
> connection to talk securely to some LDAP server elsewhere. All without an
> unencrypted keyfile or a password ever existing on disk, hence the added
> security.
>
> If you feel that supporting encrypted keyfiles in slapd is a bad design
> choice, I'm willing to rework the patch to drop that part and only keep the
> API-level support. Personally, I would argue that it doesn't hurt to
> support the feature, although perhaps my documentation changes could do a
> better job emphasizing the inherent security limitations. Let me know what
> you think (or if this discussion should take place on a list, let me know
> which/where).
>
>
> On Wed, Feb 22, 2017 at 1:11 PM, Howard Chu <hyc@symas.com> wrote:
>
>> ahnolds@gmail.com wrote:
>>
>>> Full_Name: Alec Cooper
>>> Version: HEAD of master branch
>>> OS: Ubuntu Linux 16.04
>>> URL: ftp://ftp.openldap.org/incoming/Alec-Cooper-160827.patch
>>> Submission from: (NULL) (73.134.243.211)
>>>
>>>
>>> Adding support for encrypted server private keys.
>>>
>>
>> Thank you for your submission. I must compliment you on providing such a
>> comprehensive and well-written contribution. Unfortunately the feature
>> itself is clearly not useful. Perhaps you should have raised this topic on
>> the openldap-devel list for discussion before spending your time writing it.
>>
>> All your feature does is embed the encryption key in the filesystem, so
>> an encrypted private key is still no more secure than an unencrypted one.
>> It still just depends on setting proper file access permissions, and the
>> current documentation already makes that point.
>>
>> Indeed, all it does is give the false illusion of enhancing security, and
>> followups like balmerpeak92@gmail.com's shows that people will easily
>> fall for such illusions.
>>
>> I regret having to reject such a well written contribution, but we cannot
>> in good conscience accept a security feature that doesn't actually improve
>> security.
>>
>>>
>>> The meat of this patch is changes to tls2.c, tls_g.c, tls_m.c, and
>>> tls_o.c to
>>> send a password to the underlying TLS library.
>>>
>>> Changes to ldap.h, init.c and ldap-int.h expose the new
>>> LDAP_OPT_X_TLS_KEYPASSWORD in the main API.
>>>
>>> Changes in the contrib/ldapc++ directory expose the corresponding
>>> TlsOptions::KEYPASSWORD option in the C++ API.
>>>
>>> Changes in the servers directory expose equivalent options for servers as
>>> configuration file entries or environment variables.
>>>
>>> Changes in the doc directory add documentation about the new options and
>>> remove
>>> statements that indicated that encrypted keyfiles are not supported.
>>>
>>> New files in the test directory are for testing TLS connections, both in
>>> general
>>> and with encrypted keyfiles. Tests pass for OpenSSL and GnuTLS using PEM
>>> formatted certs and keys, and for MozNSS using cert/key databases. The
>>> new unit
>>> test (test065-tls) has been written to detect when using NSS, and use the
>>> cert/key databases in this case. I have been unable to get a working
>>> version of
>>> libnsspem, so I cannot test MozNSS with (or without) encrypted keyfiles -
>>> testing for this case would be welcome!
>>>
>>> Notice of origin: The attached patch file is derived from OpenLDAP
>>> Software. All
>>> of the modifications to OpenLDAP Software represented in the following
>>> patch
>>> were developed by Alec Cooper ahnolds@gmail.com. I have not assigned
>>> rights
>>> and/or interest in this work to any party.
>>> Rights statement: I, Alec Cooper, hereby place the following
>>> modifications to
>>> OpenLDAP Software (and only these modifications) into the public domain.
>>> Hence,
>>> these modifications may be freely used and/or redistributed for any
>>> purpose with
>>> or without attribution and/or other notice.
>>>
>>> The patch has been uploaded to the OpenLDAP FTP server and can be found
>>> at
>>> ftp://ftp.openldap.org/incoming/Alec-Cooper-160827.patch
>>>
>>>
>>>
>>
>> --
>> -- Howard Chu
>> CTO, Symas Corp. http://www.symas.com
>> Director, Highland Sun http://highlandsun.com/hyc/
>> Chief Architect, OpenLDAP http://www.openldap.org/project/
>>
>
>
--94eb2c0477b011a5720557daad8c
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
<div dir=3D"ltr">I take it that this enhancement on the client side API isn=
't something you think would be useful. If that's the case, feel fr=
ee to close this ticket, and best of luck with your ongoing development!</d=
iv><div class=3D"gmail_extra"><br><div class=3D"gmail_quote">On Wed, Feb 22=
, 2017 at 8:49 PM, Alec C <span dir=3D"ltr"><<a href=3D"mailto:ahnolds@g=
mail.com" target=3D"_blank">ahnolds@gmail.com</a>></span> wrote:<br><blo=
ckquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #c=
cc solid;padding-left:1ex"><div dir=3D"ltr">I completely agree that this do=
esn't add any security when running slapd. However, when I originally w=
rote this patch, I was more targeting API usage, and in particular, client-=
side API usage. My goal was to allow a user to present an encrypted key (st=
ored on disk) and a password (only held in memory), and use these to query =
a secure LDAP server. The issue of how the password got into memory is cert=
ainly beyond the scope of OpenLDAP in this case, but it certainly could be =
done securely in a way that wouldn't leave it exposed to a third-party =
with file-system access.<div><br></div><div>For example (in the use case th=
at motivated me originally), an sysadmin could input the password through a=
n online form, submit said form to a Python webserver over HTTPS, the Pytho=
n code could pass the password to OpenLDAP through a Python interface like =
python-ldap (<a href=3D"https://www.python-ldap.org/"; target=3D"_blank">htt=
ps://www.python-ldap.org/</a>)<wbr>, and then use the LDAPS or STARTTLS con=
nection to talk securely to some LDAP server elsewhere. All without an unen=
crypted keyfile or a password ever existing on disk, hence the added securi=
ty.<div><br></div><div>If you feel that supporting encrypted keyfiles in sl=
apd is a bad design choice, I'm willing to rework the patch to drop tha=
t part and only keep the API-level support. Personally, I would argue that =
it doesn't hurt to support the feature, although perhaps my documentati=
on changes could do a better job emphasizing the inherent security limitati=
ons. Let me know what you think (or if this discussion should take place on=
a list, let me know which/where).=C2=A0</div></div><div><br></div></div><d=
iv class=3D"HOEnZb"><div class=3D"h5"><div class=3D"gmail_extra"><br><div c=
lass=3D"gmail_quote">On Wed, Feb 22, 2017 at 1:11 PM, Howard Chu <span dir=
=3D"ltr"><<a href=3D"mailto:hyc@symas.com"; target=3D"_blank">hyc@symas.c=
om</a>></span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"marg=
in:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><a href=3D"mailt=
o:ahnolds@gmail.com" target=3D"_blank">ahnolds@gmail.com</a> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">
Full_Name: Alec Cooper<br>
Version: HEAD of master branch<br>
OS: Ubuntu Linux 16.04<br>
URL: <a href=3D"ftp://ftp.openldap.org/incoming/Alec-Cooper-160827.patch"; r=
el=3D"noreferrer" target=3D"_blank">ftp://ftp.openldap.org/incomin<wbr>g/Al=
ec-Cooper-160827.patch</a><br>
Submission from: (NULL) (73.134.243.211)<br>
<br>
<br>
Adding support for encrypted server private keys.<br>
</blockquote>
<br>
Thank you for your submission. I must compliment you on providing such a co=
mprehensive and well-written contribution. Unfortunately the feature itself=
is clearly not useful. Perhaps you should have raised this topic on the op=
enldap-devel list for discussion before spending your time writing it.<br>
<br>
All your feature does is embed the encryption key in the filesystem, so an =
encrypted private key is still no more secure than an unencrypted one. It s=
till just depends on setting proper file access permissions, and the curren=
t documentation already makes that point.<br>
<br>
Indeed, all it does is give the false illusion of enhancing security, and f=
ollowups like <a href=3D"mailto:balmerpeak92@gmail.com"; target=3D"_blank">b=
almerpeak92@gmail.com</a>'s shows that people will easily fall for such=
illusions.<br>
<br>
I regret having to reject such a well written contribution, but we cannot i=
n good conscience accept a security feature that doesn't actually impro=
ve security.<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">
<br>
The meat of this patch is changes to tls2.c, tls_g.c, tls_m.c, and tls_o.c =
to<br>
send a password to the underlying TLS library.<br>
<br>
Changes to ldap.h, init.c and ldap-int.h expose the new<br>
LDAP_OPT_X_TLS_KEYPASSWORD in the main API.<br>
<br>
Changes in the contrib/ldapc++ directory expose the corresponding<br>
TlsOptions::KEYPASSWORD option in the C++ API.<br>
<br>
Changes in the servers directory expose equivalent options for servers as<b=
r>
configuration file entries or environment variables.<br>
<br>
Changes in the doc directory add documentation about the new options and re=
move<br>
statements that indicated that encrypted keyfiles are not supported.<br>
<br>
New files in the test directory are for testing TLS connections, both in ge=
neral<br>
and with encrypted keyfiles. Tests pass for OpenSSL and GnuTLS using PEM<br=
>
formatted certs and keys, and for MozNSS using cert/key databases. The new =
unit<br>
test (test065-tls) has been written to detect when using NSS, and use the<b=
r>
cert/key databases in this case. I have been unable to get a working versio=
n of<br>
libnsspem, so I cannot test MozNSS with (or without) encrypted keyfiles -<b=
r>
testing for this case would be welcome!<br>
<br>
Notice of origin: The attached patch file is derived from OpenLDAP Software=
. All<br>
of the modifications to OpenLDAP Software represented in the following patc=
h<br>
were developed by Alec Cooper <a href=3D"mailto:ahnolds@gmail.com"; target=
=3D"_blank">ahnolds@gmail.com</a>. I have not assigned rights<br>
and/or interest in this work to any party.<br>
Rights statement: I, Alec Cooper, hereby place the following modifications =
to<br>
OpenLDAP Software (and only these modifications) into the public domain. He=
nce,<br>
these modifications may be freely used and/or redistributed for any purpose=
with<br>
or without attribution and/or other notice.<br>
<br>
The patch has been uploaded to the OpenLDAP FTP server and can be found at<=
br>
<a href=3D"ftp://ftp.openldap.org/incoming/Alec-Cooper-160827.patch"; rel=3D=
"noreferrer" target=3D"_blank">ftp://ftp.openldap.org/incomin<wbr>g/Alec-Co=
oper-160827.patch</a><br>
<br>
<br><span class=3D"m_-1938021547848690298HOEnZb"><font color=3D"#888888">
</font></span></blockquote><span class=3D"m_-1938021547848690298HOEnZb"><fo=
nt color=3D"#888888">
<br>
<br>
-- <br>
=C2=A0 -- Howard Chu<br>
=C2=A0 CTO, Symas Corp.=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0<a href=3D"=
http://www.symas.com"; rel=3D"noreferrer" target=3D"_blank">http://www.symas=
.com</a><br>
=C2=A0 Director, Highland Sun=C2=A0 =C2=A0 =C2=A0<a href=3D"http://highland=
sun.com/hyc/" rel=3D"noreferrer" target=3D"_blank">http://highlandsun.com/h=
yc/</a><br>
=C2=A0 Chief Architect, OpenLDAP=C2=A0 <a href=3D"http://www.openldap.org/p=
roject/" rel=3D"noreferrer" target=3D"_blank">http://www.openldap.org/proje=
c<wbr>t/</a><br>
</font></span></blockquote></div><br></div>
</div></div></blockquote></div><br></div>
--94eb2c0477b011a5720557daad8c--