[Freeipa-users] Re: kpasswd: Preauthentication failed getting initial ticket

[Alexander Bokovoy]

On ti, 03 heinä 2018, lune voo via FreeIPA-users wrote:
> Hello !
>
> I contact you because I encounter a problem when I use kpasswd using python
> popen function.
> I use freeipa 3.0 and python 2.6.6.
>
> Here is what I do in python :
>
> input_process = otp + '\n' + password + '\n' + password 
Here you
provide otp (what is this? A 2FA token value?), password and
password.

> cmd = 'kpasswd %s' % user_login
> cmd_and_args = shlex.split(cmd)
> p = Popen(cmd_and_args, stdout=PIPE, stdin=PIPE, stderr=STDOUT)
> (output, error) = p.communicate(input=input_process)
>
>
> Before doing that, I performed the following command in order to have more
> logs :
> export KRB5_TRACE=/dev/stdout
>
> And here is what I see in the logs :
> ###
> [47700] 1530630765.610794: Getting initial credentials for test_user@MYREALM
> [47700] 1530630765.610945: FAST armor ccache: FILE:/tmp/krb5cc_testuser
> [47700] 1530630765.610998: Retrieving admin@MYREALM ->
> krb5_ccache_conf_data/fast_avail/krbtgt\/MYREALM\@MYREALM@X-CACHECONF: from
> FILE:/tmp/krb5cc_testuser with result: 0/Success
> [47700] 1530630765.611003: Read config in FILE:/tmp/krb5cc_testuser for
> krbtgt/MYREALM@MYREALM: fast_avail: yes
> [47700] 1530630765.611006: Using FAST due to armor ccache negotiation result
> [47700] 1530630765.611016: Getting credentials admin@MYREALM ->
> krbtgt/MYREALM@MYREALM using ccache FILE:/tmp/krb5cc_testuser
> [47700] 1530630765.611044: Retrieving admin@MYREALM ->
> krbtgt/MYREALM@MYREALM from FILE:/tmp/krb5cc_testuser with result: 0/Success
> [47700] 1530630765.611061: Armor ccache sesion key: aes256-cts/2559
> [47700] 1530630765.611089: Creating authenticator for admin@MYREALM ->
> krbtgt/MYREALM@MYREALM, seqnum 0, subkey aes256-cts/7F39, session key
> aes256-cts/2559
> [47700] 1530630765.611168: FAST armor key: aes256-cts/79AB
> [47700] 1530630765.611179: Setting initial creds service to kadmin/changepw
> [47700] 1530630765.611184: FAST armor ccache: FILE:/tmp/krb5cc_testuser
> [47700] 1530630765.611208: Retrieving admin@MYREALM ->
> krb5_ccache_conf_data/fast_avail/krbtgt\/MYREALM\@MYREALM@X-CACHECONF: from
> FILE:/tmp/krb5cc_testuser with result: 0/Success
> [47700] 1530630765.611212: Read config in FILE:/tmp/krb5cc_testuser for
> krbtgt/MYREALM@MYREALM: fast_avail: yes
> [47700] 1530630765.611213: Using FAST due to armor ccache negotiation result
> [47700] 1530630765.611219: Getting credentials admin@MYREALM ->
> krbtgt/MYREALM@MYREALM using ccache FILE:/tmp/krb5cc_testuser
> [47700] 1530630765.611240: Retrieving admin@MYREALM ->
> krbtgt/MYREALM@MYREALM from FILE:/tmp/krb5cc_testuser with result: 0/Success
> [47700] 1530630765.611245: Armor ccache sesion key: aes256-cts/2559
> [47700] 1530630765.611256: Creating authenticator for admin@MYREALM ->
> krbtgt/MYREALM@MYREALM, seqnum 0, subkey aes256-cts/2BFD, session key
> aes256-cts/2559
> [47700] 1530630765.611288: FAST armor key: aes256-cts/62C4
> [47700] 1530630765.611299: Encoding request body and padata into FAST
> request
> [47700] 1530630765.611333: Sending request (1019 bytes) to MYREALM
> [47700] 1530630765.611418: Resolving hostname ipamasterhostname
> [47700] 1530630765.611608: Initiating TCP connection to stream
> ipamasterIP:88
> [47700] 1530630765.611769: Sending TCP request to stream ipamasterIP:88
> [47700] 1530630765.675154: Received answer from stream ipamasterIP:88
> [47700] 1530630765.675208: Response was from master KDC
> [47700] 1530630765.675238: Received error from KDC: -1765328359/Additional
> pre-authentication required
> [47700] 1530630765.675249: Decoding FAST response
> [47700] 1530630765.675311: Processing preauth types: 136, 19, 138, 133, 137
> [47700] 1530630765.675319: Received cookie: MIT
> Password for test_user@MYREALM:  
Here you are asked for a password.

> [47700] 1530630765.682884: Preauth module
> encrypted_challenge (138) (flags=1) returned: 0/Success
> [47700] 1530630765.682889: Produced preauth for next request: 133, 138
> [47700] 1530630765.682891: Encoding request body and padata into FAST
> request
> [47700] 1530630765.682951: Sending request (1118 bytes) to MYREALM
> [47700] 1530630765.682967: Resolving hostname ipamasterhostname
> [47700] 1530630765.683098: Initiating TCP connection to stream
> ipamasterIP:88
> [47700] 1530630765.683180: Sending TCP request to stream ipamasterIP:88
> [47700] 1530630765.756232: Received answer from stream ipamasterIP:88
> [47700] 1530630765.756302: Response was from master KDC
> [47700] 1530630765.756321: Received error from KDC:
> -1765328360/Preauthentication failed
> [47700] 1530630765.756325: Decoding FAST response
> [47700] 1530630765.756376: Preauth tryagain input types: 136, 19, 138, 133,
> 137
> kpasswd: Preauthentication failed getting initial ticket 
And your password (what
kpasswd uses as a password) is incorrect (to
what KDC considers you have as a password).

> )
> ###
>
> I don't understand yet why the commande kpasswd is failing ?
>
> My ticket admin is good.
> My ticket cache is used only by me.
>
> May you help me to understand what is going on please ? 
Try first to get this
working interactively.

> Is there a way to use ipa python library to perform a kpasswd instead
> of
> popen of kpasswd command ?
>
> Best regards.
>
> Lune 
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-- 
/ Alexander Bokovoy
Sr. Principal Software Engineer
Security / Identity Management Engineering
Red Hat Limited, Finland