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

[hyc@symas.com]

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}
>>> =3D> 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 sa=
lt, the
>>> '-T' seems to work as expected:
>>> (a) slappasswd -c 123
>>> =3D> 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 alre=
ady
>>> provided.
>> Unable to reproduce, SSHA works fine here.
>>
>> Obviously you can't use a fixed salt with SSHA, that's the point of it=
s 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 o=
utput 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 o=
mitted. This
>> is already documented in the manpage.
>=20
> 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 l=
ong time. In a
> Linux machine with internet, just copy paste this:
>=20
>     docker run --name slappasswd --rm -ti centos:7 bash
>=20
>     yum install openldap-servers -y
>=20
>     cat <<EOF >/makeSecret.py
>     import os
>     import sys
>     import hashlib
>     from base64 import urlsafe_b64encode as encode
>     from base64 import urlsafe_b64decode as decode
>=20
>     def makeSecret(password):
>     =C2=A0=C2=A0=C2=A0 salt =3D os.urandom(4)
>     =C2=A0=C2=A0=C2=A0 h =3D hashlib.sha1(password)
>     =C2=A0=C2=A0=C2=A0 h.update(salt)
>     =C2=A0=C2=A0=C2=A0 return "{SSHA}" + encode(h.digest() + salt)
>=20
>     if __name__ =3D=3D '__main__':
>     =C2=A0=C2=A0=C2=A0 print(makeSecret(sys.argv[1]))
>     EOF
>=20
>     cat <<EOF >/checkPassword.py
>     import os
>     import sys
>     import hashlib
>     from base64 import urlsafe_b64encode as encode
>     from base64 import urlsafe_b64decode as decode
>=20
>     def checkPassword(challenge_password, password):
>     =C2=A0=C2=A0=C2=A0 challenge_bytes =3D decode(challenge_password[6:=
])
>     =C2=A0=C2=A0=C2=A0 digest =3D challenge_bytes[:20]
>     =C2=A0=C2=A0=C2=A0 salt =3D challenge_bytes[20:]
>     =C2=A0=C2=A0=C2=A0 hr =3D hashlib.sha1(password)
>     =C2=A0=C2=A0=C2=A0 hr.update(salt)
>     =C2=A0=C2=A0=C2=A0 return digest =3D=3D hr.digest()
>=20
>     if __name__ =3D=3D '__main__':
>     =C2=A0=C2=A0=C2=A0 print(checkPassword(sys.argv[1], sys.argv[2]))
>     EOF
>=20
>     python /checkPassword.py $(python /makeSecret.py d) d
>=20
>     python /checkPassword.py $(slappasswd -s d) d
>=20
>     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
>     # =3D> shows no newline:
>     #Begin-d-End
>=20
> It will show you that all hash works except the part with slappasswd -T=
, and I checked the newline.

I've run your steps. Your test is still invalid. Learn how to use the ech=
o command.

####
[root@507ab0515ed6 /]# od -xc /run/secrets/rootpw
0000000    0a64
          d  \n
0000002
[root@507ab0515ed6 /]# echo -n d > /run/secrets/rootpw
[root@507ab0515ed6 /]# python /checkPassword.py $(slappasswd -T /run/secr=
ets/rootpw) d
Warning: Password file /run/secrets/rootpw is publicly readable/writeable
True
[root@507ab0515ed6 /]#
####

Closing this ITS.


>=20
>>> I saw the same issue in another openldap mail:
>>> https://www.openldap.org/lists/openldap-software/200805/msg00060.html=
 but no
>>> answer.
>>>
>>>


--=20
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/