[Freeipa-users] cannot access to freeipa client's linux share from windows
Alexander Bokovoy
abokovoy at redhat.com
Fri Dec 2 10:20:57 UTC 2016
On pe, 02 joulu 2016, Fujisan wrote:
>I'm not sure my problem is linked to this 'dedicated keytab file' with
>FILE: before the path to keytab file.
Yes, it does. Your client log below reports that the server cannot
communicate with you because _the_server_ is unable to read its keytab
when initializing GENSEC backed gssapi_krb5 and thus client switches to
SPNEGO which also fails as the server cannot work without proper keytab
using kerberos and password-based auth is not possible.
>
># smbclient -d3 -L \\10.0.21.200 -U smith
>lp_load_ex: refreshing parameters
>Initialising global parameters
>rlimit_max: increasing rlimit_max (1024) to minimum Windows limit (16384)
>Processing section "[global]"
>lp_load_ex: changing to config backend registry
>Initialising global parameters
>rlimit_max: increasing rlimit_max (1024) to minimum Windows limit (16384)
>lp_load_ex: refreshing parameters
>Initialising global parameters
>rlimit_max: increasing rlimit_max (1024) to minimum Windows limit (16384)
>Processing section "[global]"
>added interface eno1 ip=10.0.21.18 bcast=10.0.21.31 netmask=255.255.255.240
>Client started (version 4.5.1).
>Enter smith's password:
>Connecting to 10.0.21.200 at port 445
>Doing spnego session setup (blob length=74)
>got OID=1.3.6.1.4.1.311.2.2.10
>got principal=not_defined_in_RFC4178 at please_ignore
>GENSEC backend 'gssapi_spnego' registered
>GENSEC backend 'gssapi_krb5' registered
>GENSEC backend 'gssapi_krb5_sasl' registered
>GENSEC backend 'spnego' registered
>GENSEC backend 'schannel' registered
>GENSEC backend 'naclrpc_as_system' registered
>GENSEC backend 'sasl-EXTERNAL' registered
>GENSEC backend 'ntlmssp' registered
>GENSEC backend 'ntlmssp_resume_ccache' registered
>GENSEC backend 'http_basic' registered
>GENSEC backend 'http_ntlm' registered
>Got challenge flags:
>Got NTLMSSP neg_flags=0x628a8215
>NTLMSSP: Set final flags:
>Got NTLMSSP neg_flags=0x62088215
>NTLMSSP Sign/Seal - Initialising with flags:
>Got NTLMSSP neg_flags=0x62088215
>SPNEGO login failed: Logon failure
>session setup failed: NT_STATUS_LOGON_FAILURE
>
>On Fri, Dec 2, 2016 at 10:57 AM, Alexander Bokovoy <abokovoy at redhat.com>
>wrote:
>
>> On pe, 02 joulu 2016, Fujisan wrote:
>>
>>> Alexander,
>>>
>>> I have now in my conf on server A and client B
>>>
>>> dedicated keytab file = /etc/samba/samba.keytab
>>>
>>> instead of
>>>
>>> dedicated keytab file = FILE:/etc/samba/samba.keytab
>>>
>>>
>>> But unfortunately, it did not solve the problem.
>>>
>> It did solve for me. The offending commit in Samba is c2f5c30b
>>
>> $ git tag --contains c2f5c30b|grep samba
>> samba-4.5.0
>> samba-4.5.0rc1
>> samba-4.5.0rc2
>> samba-4.5.0rc3
>> samba-4.5.1
>>
>> It has following code:
>> +krb5_error_code smb_krb5_open_keytab(krb5_context context,
>> + const char *keytab_name_req,
>> + bool write_access,
>> + krb5_keytab *keytab)
>> +{
>> + if (keytab_name_req != NULL) {
>> + if (keytab_name_req[0] != '/') {
>> + return KRB5_KT_BADNAME;
>> + }
>> + }
>> +
>> + return smb_krb5_open_keytab_relative(context,
>> + keytab_name_req,
>> + write_access,
>> + keytab);
>> +}
>>
>> It is the check for keytab_name_req[0] not starting from '/' what causes
>> the break.
>>
>>
>>
>>>
>>>
>>> On Fri, Dec 2, 2016 at 10:29 AM, Alexander Bokovoy <abokovoy at redhat.com>
>>> wrote:
>>>
>>> On to, 01 joulu 2016, Fujisan wrote:
>>>>
>>>> Hello,
>>>>>
>>>>> I have upgraded a client and a freeipa server from Fedora 24 to 25
>>>>> recently.
>>>>> And I *cannot* access linux shares located on the F25 freeipa client
>>>>> from
>>>>> a
>>>>> windows desktop.
>>>>> But I can access linux shares located on the F25 freeipa server from
>>>>> that
>>>>> windows desktop.
>>>>> And I can access linux shares located on the F24 freeipa client from
>>>>> that
>>>>> windows desktop.
>>>>>
>>>>> To be clear, I have:
>>>>> A/ 1 F25 freeipa server
>>>>> B/ 1 F25 freeipa client
>>>>> C/ 1 F24 freeipa client
>>>>> D/ 1 windows desktop
>>>>>
>>>>> I can access linux shares of A from D.
>>>>> I can access linux shares of C from D.
>>>>> I *cannot* access linux shares of B from D.
>>>>>
>>>>> I get these messages on B in /var/log/samba/log.10.0.21.247 :
>>>>>
>>>>> [2016/12/01 11:42:19.218759, 1] ../source3/librpc/crypto/gse_
>>>>> krb5.c:534(fill_mem_keytab_from_dedicated_keytab)
>>>>> ../source3/librpc/crypto/gse_krb5.c:534: smb_krb5_open_keytab failed
>>>>> (Key
>>>>> table name malformed)
>>>>> [2016/12/01 11:42:19.218800, 1] ../source3/librpc/crypto/gse_
>>>>> krb5.c:627(gse_krb5_get_server_keytab)
>>>>> ../source3/librpc/crypto/gse_krb5.c:627: Error! Unable to set mem
>>>>> keytab
>>>>> - -1765328205
>>>>> [2016/12/01 11:42:19.218823, 1] ../auth/gensec/gensec_start.c:
>>>>> 698(gensec_start_mech)
>>>>> Failed to start GENSEC server mech gse_krb5: NT_STATUS_INTERNAL_ERROR
>>>>> [2016/12/01 11:42:19.261611, 1] ../source3/librpc/crypto/gse_
>>>>> krb5.c:534(fill_mem_keytab_from_dedicated_keytab)
>>>>> ../source3/librpc/crypto/gse_krb5.c:534: smb_krb5_open_keytab failed
>>>>> (Key
>>>>> table name malformed)
>>>>> [2016/12/01 11:42:19.261638, 1] ../source3/librpc/crypto/gse_
>>>>> krb5.c:627(gse_krb5_get_server_keytab)
>>>>> ../source3/librpc/crypto/gse_krb5.c:627: Error! Unable to set mem
>>>>> keytab
>>>>> - -1765328205
>>>>> [2016/12/01 11:42:19.261653, 1] ../auth/gensec/gensec_start.c:
>>>>> 698(gensec_start_mech)
>>>>> Failed to start GENSEC server mech gse_krb5: NT_STATUS_INTERNAL_ERROR
>>>>> [2016/12/01 11:42:19.263330, 2] ../source3/auth/auth.c:315(
>>>>> auth_check_ntlm_password)
>>>>> check_ntlm_password: Authentication for user [smith] -> [smith] FAILED
>>>>> with error NT_STATUS_NO_SUCH_USER
>>>>> [2016/12/01 11:42:19.263380, 2] ../auth/gensec/spnego.c:720(
>>>>> gensec_spnego_server_negTokenTarg)
>>>>> SPNEGO login failed: NT_STATUS_NO_SUCH_USER
>>>>> [2016/12/01 11:42:19.270531, 1] ../source3/librpc/crypto/gse_
>>>>> krb5.c:534(fill_mem_keytab_from_dedicated_keytab)
>>>>> ../source3/librpc/crypto/gse_krb5.c:534: smb_krb5_open_keytab failed
>>>>> (Key
>>>>> table name malformed)
>>>>> [2016/12/01 11:42:19.270562, 1] ../source3/librpc/crypto/gse_
>>>>> krb5.c:627(gse_krb5_get_server_keytab)
>>>>> ../source3/librpc/crypto/gse_krb5.c:627: Error! Unable to set mem
>>>>> keytab
>>>>> - -1765328205
>>>>> [2016/12/01 11:42:19.270586, 1] ../auth/gensec/gensec_start.c:
>>>>> 698(gensec_start_mech)
>>>>> Failed to start GENSEC server mech gse_krb5: NT_STATUS_INTERNAL_ERROR
>>>>> [2016/12/01 11:42:19.313479, 1] ../source3/librpc/crypto/gse_
>>>>> krb5.c:534(fill_mem_keytab_from_dedicated_keytab)
>>>>> ../source3/librpc/crypto/gse_krb5.c:534: smb_krb5_open_keytab failed
>>>>> (Key
>>>>> table name malformed)
>>>>> [2016/12/01 11:42:19.313506, 1] ../source3/librpc/crypto/gse_
>>>>> krb5.c:627(gse_krb5_get_server_keytab)
>>>>> ../source3/librpc/crypto/gse_krb5.c:627: Error! Unable to set mem
>>>>> keytab
>>>>> - -1765328205
>>>>> [2016/12/01 11:42:19.313523, 1] ../auth/gensec/gensec_start.c:
>>>>> 698(gensec_start_mech)
>>>>> Failed to start GENSEC server mech gse_krb5: NT_STATUS_INTERNAL_ERROR
>>>>> [2016/12/01 11:42:19.315256, 2] ../source3/auth/auth.c:315(
>>>>> auth_check_ntlm_password)
>>>>> check_ntlm_password: Authentication for user [smith] -> [smith] FAILED
>>>>> with error NT_STATUS_NO_SUCH_USER
>>>>> [2016/12/01 11:42:19.315291, 2] ../auth/gensec/spnego.c:720(
>>>>> gensec_spnego_server_negTokenTarg)
>>>>> SPNEGO login failed: NT_STATUS_NO_SUCH_USER
>>>>>
>>>>> Also from the F25 server, I have the following when I run smbclient
>>>>>
>>>>> f25server # smbclient -k -L f25desktop.mydomain
>>>>> lp_load_ex: changing to config backend registry
>>>>> session setup failed: NT_STATUS_LOGON_FAILURE
>>>>>
>>>>> But if i run it with a F24 desktop, it works:
>>>>>
>>>>> f25server # smbclient -k -L f24desktop.mydomain
>>>>> lp_load_ex: changing to config backend registry
>>>>> Domain=[MYDOMAIN] OS=[Windows 6.1] Server=[Samba 4.4.7]
>>>>>
>>>>> Sharename Type Comment
>>>>> --------- ---- -------
>>>>> IPC$ IPC IPC Service (Samba Server Version 4.4.7)
>>>>> data Disk /data on f24desktop
>>>>> data2 Disk /data2 on f24desktop
>>>>> data3 Disk /data3 on f24desktop
>>>>> backup Disk /backup on f24desktop
>>>>> [...]
>>>>>
>>>>>
>>>>> net conf list on the f25desktop gives:
>>>>>
>>>>> f25desktop # net conf list
>>>>> [global]
>>>>> workgroup = MYDOMAIN
>>>>> realm = MYDOMAIN
>>>>> netbios name = F25SERVER
>>>>> server string = Samba Server Version %v
>>>>> kerberos method = dedicated keytab
>>>>> dedicated keytab file = FILE:/etc/samba/samba.keytab
>>>>>
>>>>> There seem to be a change in Samba 4.5.0 which uses 'dedicated keytab
>>>> file' value as it is when constructing a memory keytab. As result,
>>>> libkrb5 is confused and does not know which keytab processing routine to
>>>> use (MEMORY:FILE:/etc/samba/samba.keytab is invalid).
>>>>
>>>> You can replace the value by removing FILE: right now:
>>>>
>>>> net conf setparm global 'dedicated keytab file' /etc/samba/samba.keytab
>>>>
>>>> When no prefix is used, libkrb5 will default to FILE: itself.
>>>>
>>>> We are going to look at changing the Samba code to strip the prefix from
>>>> the 'dedicated keytab file' when applying it to memory-based keytabs.
>>>>
>>>> --
>>>> / Alexander Bokovoy
>>>>
>>>>
>> --
>> / Alexander Bokovoy
>>
--
/ Alexander Bokovoy
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