[Samba] SIGSEGV with pam_winbind kerberos authentication

[Prunk Dump]

Hello,

I can't get Kerberos authentication works with my Linux clients.

Server : samba 4.1.4 (compiled from source)
Client : Debian Wheezy with sernet-samba 4.0.17-8

Without Kerberos authentication, everything works :

-> the domain users can log with pam_winbind (with ssh, gdm ....).
-> "kinit myuser at MYREALM" works fine.
-> "wbinfo -K MYDOM\\myuser" works.
-> all the others winbind related commands works (wbinfo, id, getent ....).
-> If I do a standard pam_winbind login followed by the kinit command,
the user can access to all the kerberized services.

But with krb5_auth. If I log as a domain user through SSH or GDM, the
kerberos ticket is created in /tmp/ but I get the following error :

(/var/log/syslog)
[2014/04/26 10:07:16.362838,  0] ../lib/util/fault.c:72(fault_report)
===============================================================
[2014/04/26 10:07:16.362981,  0] ../lib/util/fault.c:73(fault_report)
INTERNAL ERROR: Signal 11 in pid 3354 (4.0.17-SerNet-Debian-8.wheezy)
Please read the Trouble-Shooting section of the Samba HOWTO
[2014/04/26 10:07:16.363061,  0] ../lib/util/fault.c:75(fault_report)
===============================================================
[2014/04/26 10:07:16.363113,  0] ../source3/lib/util.c:810(smb_panic_s3)
PANIC (pid 3354): internal error
[2014/04/26 10:07:16.363588,  0] ../source3/lib/util.c:921(log_stack_trace)
BACKTRACE: 25 stack frames:
#0 /usr/lib/x86_64-linux-gnu/samba/libsmbconf.so.0(log_stack_trace+0x2d)
[0x7f4b0d47667b]
#1 /usr/lib/x86_64-linux-gnu/samba/libsmbconf.so.0(smb_panic_s3+0x69)
[0x7f4b0d4767a5]
#2 /usr/lib/x86_64-linux-gnu/samba/libsamba-util.so.0(smb_panic+0x2d)
[0x7f4b1266c451]
#3 /usr/lib/x86_64-linux-gnu/samba/libsamba-util.so.0(+0x1b77e) [0x7f4b1266c77e]
#4 /lib/x86_64-linux-gnu/libpthread.so.0(+0xf030) [0x7f4b12a9e030]
#5 /usr/lib/x86_64-linux-gnu/samba/libkrb5-samba4.so.26(krb5_storage_free+0x18)
[0x7f4b0ff3043b]
#6 /usr/lib/x86_64-linux-gnu/samba/libkrb5-samba4.so.26(+0x41ccd)
[0x7f4b0ff18ccd]
#7 /usr/lib/x86_64-linux-gnu/samba/libkrb5-samba4.so.26(krb5_kt_end_seq_get+0x3a)
[0x7f4b0ff1817e]
#8 /usr/lib/x86_64-linux-gnu/samba/libgse.so(+0x9b04) [0x7f4b0e224b04]
#9 /usr/lib/x86_64-linux-gnu/samba/libgse.so(gse_krb5_get_server_keytab+0x3e8)
[0x7f4b0e224f3d]
#10 /usr/lib/x86_64-linux-gnu/samba/libgse.so(+0xba82) [0x7f4b0e226a82]
#11 /usr/lib/x86_64-linux-gnu/samba/libgensec.so.0(gensec_start_mech+0x11e)
[0x7f4b0f27b3f8]
#12 /usr/lib/x86_64-linux-gnu/samba/libgensec.so.0(gensec_start_mech_by_oid+0xe1)
[0x7f4b0f27b79e]
#13 /usr/sbin/winbindd(kerberos_return_pac+0x62d) [0x7f4b12efb98d]
#14 /usr/sbin/winbindd(winbindd_dual_pam_auth+0x70b) [0x7f4b12f0f7e7]
#15 /usr/sbin/winbindd(+0x5b370) [0x7f4b12f28370]
#16 /usr/sbin/winbindd(+0x5b60d) [0x7f4b12f2860d]
#17 /usr/lib/x86_64-linux-gnu/samba/libtevent.so.0(+0x4f3b) [0x7f4b11e07f3b]
#18 /usr/lib/x86_64-linux-gnu/samba/libtevent.so.0(tevent_common_loop_immediate+0x133)
[0x7f4b11e07dca]
#19 /usr/lib/x86_64-linux-gnu/samba/libsmbconf.so.0(run_events_poll+0x52)
[0x7f4b0d497e6b]
#20 /usr/lib/x86_64-linux-gnu/samba/libsmbconf.so.0(+0x4a1e9) [0x7f4b0d4981e9]
#21 /usr/lib/x86_64-linux-gnu/samba/libtevent.so.0(_tevent_loop_once+0x91)
[0x7f4b11e0723b]
#22 /usr/sbin/winbindd(main+0xd11) [0x7f4b12efed36]
#23 /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xfd) [0x7f4b0bd45ead]
#24 /usr/sbin/winbindd(+0x251d9) [0x7f4b12ef21d9]
[2014/04/26 10:07:16.364233,  0] ../source3/lib/dumpcore.c:312(dump_core)
   unable to change to /var/log/samba/cores/winbindd
   refusing to dump core


(/var/log/auth.log)
pam_winbind(sshd:auth): getting password (0x00000190)
pam_winbind(sshd:auth): pam_get_item returned a password
pam_winbind(sshd:auth): request wbcLogonUser failed:
WBC_ERR_AUTH_ERROR, PAM error: PAM_SYSTEM_ERR (4), NTSTATUS:
NT_STATUS_CONNECTION_DISCONNECTED, Error message was:
NT_STATUS_CONNECTION_DISCONNECTED
pam_winbind(sshd:auth): internal module error (retval =
PAM_SYSTEM_ERR(4), user = 'myuser')



Any idea how can I fix this problem ?

Baptiste.