Re: (ITS#9137) slappasswd generate wrong SSHA from file - openldap-bugs

12 Dec 2019


      This is a multi-part message in MIME format.
--------------618A3E9CC74C1DE7FC603227
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
I also tried with '-n' for slappasswd, in the test below, for '-T' and 
'-s' cases. It changed nothing.
On 12/12/2019 14:59, Antoine Tran wrote:
...
On 12/12/2019 14:02, Howard Chu wrote:
...
antoine.tran@thales-services.fr  wrote:
...
Full_Name: Antoine TRAN
Version: openldap-servers-2.4.44-21.el7_6.x86_64
OS: CentOS Linux release 7.7.1908 (Core)
URL:ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (213.190.88.94)
I use slappasswd to generate SSHA password. The issue is it behavior is
different whether I submit the password - in stdin or in command-line '-s' - and
from a secret file '-T'. Command:
slappasswd -h {SSHA}
=> write 'd' twice as password
slappasswd -h {SSHA} -s d
provides working SSHA.
But:
echo d >/run/secrets/rootpw
slappasswd -h {SSHA} -T /run/secrets/rootpw
provides a valid SSHA, but that does not match the password.
My multiple test are done by replacing rootpw in /etc/openldap/slapd.conf,
regenerating with:
systemctl stop slapd
sed -i -e "s,rootpw .*$,rootpw ${ROOTPW_HASH},g" /etc/openldap/slapd.conf
slapcat -n 0 -f /etc/openldap/slapd.conf -F /etc/openldap/slapd.d
systemctl start slapd
ldapsearch -D "${ROOTDN}" -w "${ROOTPW}"
The content of the secret file can be "d" or "d\n", it does not make a
difference. Also, if I change the schema from SSHA to just a fixed salt, the
'-T' seems to work as expected:
(a) slappasswd -c 123
=> write d twice
(b) slappasswd -c 123 -s 123
(c) slappasswd -c 123 -T /run/secrets/rootpw
(a), (b) and (c) gives the exact same hash. But I cannot put a fixed salt and
use SSHA, slappasswd prevents me from that, with an error schema already
provided.
Unable to reproduce, SSHA works fine here.
Obviously you can't use a fixed salt with SSHA, that's the point of its salt is to
be random and different every time.
I wanted to override the salt as a test, to check if we have the same 
output with a file and in command-line. But I found another way to test.
...
When using a password in a file you must ensure the trailing '\n' is omitted. This
is already documented in the manpage.
I did read and checked this point. I have written that I did not have 
a newline. But here is a simple and reproducible test, that took me 
some long time. In a Linux machine with internet, just copy paste this:
docker run --name slappasswd --rm -ti centos:7 bash

yum install openldap-servers -y

cat <<EOF >/makeSecret.py
import os
import sys
import hashlib
from base64 import urlsafe_b64encode as encode
from base64 import urlsafe_b64decode as decode

def makeSecret(password):
    salt = os.urandom(4)
    h = hashlib.sha1(password)
    h.update(salt)
    return "{SSHA}" + encode(h.digest() + salt)

if __name__ == '__main__':
    print(makeSecret(sys.argv[1]))
EOF

cat <<EOF >/checkPassword.py
import os
import sys
import hashlib
from base64 import urlsafe_b64encode as encode
from base64 import urlsafe_b64decode as decode

def checkPassword(challenge_password, password):
    challenge_bytes = decode(challenge_password[6:])
    digest = challenge_bytes[:20]
    salt = challenge_bytes[20:]
    hr = hashlib.sha1(password)
    hr.update(salt)
    return digest == hr.digest()

if __name__ == '__main__':
    print(checkPassword(sys.argv[1], sys.argv[2]))
EOF

python /checkPassword.py $(python /makeSecret.py d) d

python /checkPassword.py $(slappasswd -s d) d

mkdir -p /run/secrets/
echo d>/run/secrets/rootpw
python /checkPassword.py $(slappasswd -T /run/secrets/rootpw) d
echo Begin-$(cat /run/secrets/rootpw)-End
# => shows no newline:
#Begin-d-End


It will show you that all hash works except the part with slappasswd 
-T, and I checked the newline.
...
...
I saw the same issue in another openldap mail:
https://www.openldap.org/lists/openldap-software/200805/msg00060.html  but no
answer.
--------------618A3E9CC74C1DE7FC603227
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: 8bit
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  </head>
  <body text="#000000" bgcolor="#FFFFFF">
    <p>I also tried with '-n' for slappasswd, in the test below, for
      '-T' and '-s' cases. It changed nothing.<br>
    </p>
    <p>On 12/12/2019 14:59, Antoine Tran wrote:</p>
    <blockquote type="cite"
      cite="mid:948b761f-cb48-024a-dbb2-970493a9def2@thales-services.fr">
      <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
      On 12/12/2019 14:02, Howard Chu wrote:<br>
      <blockquote type="cite"
        cite="mid:c5070626-b60e-28f5-38a3-7871c8a0cbec@symas.com">
        <pre class="moz-quote-pre" wrap=""><a class="moz-txt-link-abbreviated" href="mailto:antoine.tran@thales-services.fr" moz-do-not-send="true">antoine.tran@thales-services.fr</a> wrote:
</pre>
        <blockquote type="cite">
          <pre class="moz-quote-pre" wrap="">Full_Name: Antoine TRAN
Version: openldap-servers-2.4.44-21.el7_6.x86_64
OS: CentOS Linux release 7.7.1908 (Core)
URL: <a class="moz-txt-link-freetext" href="ftp://ftp.openldap.org/incoming/" moz-do-not-send="true">ftp://ftp.openldap.org/incoming/</a>
Submission from: (NULL) (213.190.88.94)
I use slappasswd to generate SSHA password. The issue is it behavior is
different whether I submit the password - in stdin or in command-line '-s' - and
from a secret file '-T'. Command:
slappasswd -h {SSHA}
=&gt; write 'd' twice as password
slappasswd -h {SSHA} -s d
provides working SSHA.
But:
echo d &gt;/run/secrets/rootpw
slappasswd -h {SSHA} -T /run/secrets/rootpw
provides a valid SSHA, but that does not match the password.
My multiple test are done by replacing rootpw in /etc/openldap/slapd.conf,
regenerating with:
systemctl stop slapd
sed -i -e "s,rootpw .*$,rootpw ${ROOTPW_HASH},g" /etc/openldap/slapd.conf
slapcat -n 0 -f /etc/openldap/slapd.conf -F /etc/openldap/slapd.d
systemctl start slapd
ldapsearch -D "${ROOTDN}" -w "${ROOTPW}"
The content of the secret file can be "d" or "d\n", it does not make a
difference. Also, if I change the schema from SSHA to just a fixed salt, the
'-T' seems to work as expected:
(a) slappasswd -c 123
=&gt; write d twice
(b) slappasswd -c 123 -s 123
(c) slappasswd -c 123 -T /run/secrets/rootpw
(a), (b) and (c) gives the exact same hash. But I cannot put a fixed salt and
use SSHA, slappasswd prevents me from that, with an error schema already
provided.
</pre>
        </blockquote>
        <pre class="moz-quote-pre" wrap="">Unable to reproduce, SSHA works fine here.
Obviously you can't use a fixed salt with SSHA, that's the point of its salt is to
be random and different every time.</pre>
      </blockquote>
      I wanted to override the salt as a test, to check if we have the
      same output with a file and in command-line. But I found another
      way to test.<br>
      <blockquote type="cite"
        cite="mid:c5070626-b60e-28f5-38a3-7871c8a0cbec@symas.com">
        <pre class="moz-quote-pre" wrap="">When using a password in a file you must ensure the trailing '\n' is omitted. This
is already documented in the manpage.</pre>
      </blockquote>
      <p>I did read and checked this point. I have written that I did
        not have a newline. But here is a simple and reproducible test,
        that took me some long time. In a Linux machine with internet,
        just copy paste this:</p>
      <blockquote>
        <p>docker run --name slappasswd --rm -ti centos:7 bash<br>
          <br>
          yum install openldap-servers -y<br>
          <br>
          cat &lt;&lt;EOF &gt;/makeSecret.py<br>
          import os<br>
          import sys<br>
          import hashlib<br>
          from base64 import urlsafe_b64encode as encode<br>
          from base64 import urlsafe_b64decode as decode<br>
          <br>
          def makeSecret(password):<br>
              salt = os.urandom(4)<br>
              h = hashlib.sha1(password)<br>
              h.update(salt)<br>
              return "{SSHA}" + encode(h.digest() + salt)<br>
          <br>
          if __name__ == '__main__':<br>
              print(makeSecret(sys.argv[1]))<br>
          EOF<br>
          <br>
          cat &lt;&lt;EOF &gt;/checkPassword.py<br>
          import os<br>
          import sys<br>
          import hashlib<br>
          from base64 import urlsafe_b64encode as encode<br>
          from base64 import urlsafe_b64decode as decode<br>
          <br>
          def checkPassword(challenge_password, password):<br>
              challenge_bytes = decode(challenge_password[6:])<br>
              digest = challenge_bytes[:20]<br>
              salt = challenge_bytes[20:]<br>
              hr = hashlib.sha1(password)<br>
              hr.update(salt)<br>
              return digest == hr.digest()<br>
          <br>
          if __name__ == '__main__':<br>
              print(checkPassword(sys.argv[1], sys.argv[2]))<br>
          EOF<br>
          <br>
          python /checkPassword.py $(python /makeSecret.py d) d<br>
          <br>
          python /checkPassword.py $(slappasswd -s d) d<br>
          <br>
          mkdir -p /run/secrets/<br>
          echo d&gt;/run/secrets/rootpw<br>
          python /checkPassword.py $(slappasswd -T /run/secrets/rootpw)
          d<br>
          echo Begin-$(cat /run/secrets/rootpw)-End<br>
          # =&gt; shows no newline:<br>
          #Begin-d-End<br>
        </p>
      </blockquote>
      <p>It will show you that all hash works except the part with
        slappasswd -T, and I checked the newline.<br>
        <br>
      </p>
      <blockquote type="cite"
        cite="mid:c5070626-b60e-28f5-38a3-7871c8a0cbec@symas.com">
        <blockquote type="cite">
          <pre class="moz-quote-pre" wrap="">I saw the same issue in another openldap mail:
<a class="moz-txt-link-freetext" href="https://www.openldap.org/lists/openldap-software/200805/msg00060.html" moz-do-not-send="true">https://www.openldap.org/lists/openldap-software/200805/msg00060.html</a> but no
answer.
</pre>
        </blockquote>
      </blockquote>
    </blockquote>
  </body>
</html>
--------------618A3E9CC74C1DE7FC603227--