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Chad William Seys

2017-Feb-08 22:29 UTC

[Samba] cifs-utils: regression in (mulituser?) mounting 'CIFS VFS: Send error in SessSetup = -126'

Hello,
   On Debian 9 (stretch prerelease) I am able to mount with the following
command with root using the following command:
mount -t cifs //smb.physics.wisc.edu/smb /smb
-osec=krb5,multiuser,username=smbadmin at PHYSICS.WISC.EDU --verbose

   root can also access files as expected
   However, when cifs-utils 6.6-5 is installed, a different user cannot
access as expected:
ls /smb
ls: cannot access '/smb': Permission denied

   But when cifs-utils 6.4-1 is installed (from jessie) the different
user can access as expect.  AFAIK there are no other differences besides
the cifs-utils version.

   The first difference in syslog is "kernel: [223018.425633] CIFS VFS:
Send error in SessSetup = -126".  I'll paste the working
and non-working logs below.  The "different user" mentioned above has
UID 1494 which appears in the logs.

Thanks for your time!
C.

WORKING:
cifs-utils v 6.4-1
Feb  8 09:51:46 trog cifs.upcall: key description:
cifs.spnego;0;0;39010000;ver=0x2;host=smb.physics.wisc.edu;ip4=128.104.160.17;sec=krb5;uid0x0;creduid=0x0;user=smbadmin
at PHYSICS.WISC.EDU;pid=0x6bd0
Feb  8 09:51:46 trog cifs.upcall: ver=2
Feb  8 09:51:46 trog cifs.upcall: host=smb.physics.wisc.edu
Feb  8 09:51:46 trog cifs.upcall: ip=128.104.160.17
Feb  8 09:51:46 trog cifs.upcall: sec=1
Feb  8 09:51:46 trog cifs.upcall: uid=0
Feb  8 09:51:46 trog cifs.upcall: creduid=0
Feb  8 09:51:46 trog cifs.upcall: user=smbadmin at PHYSICS.WISC.EDU
Feb  8 09:51:46 trog cifs.upcall: pid=27600
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: scandir error on
directory '/run/user/0': No such file or directory
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: considering /tmp/krb5cc_0
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: FILE:/tmp/krb5cc_0 is
valid ccache
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: considering
/tmp/krb5cc_1494_sM11PG
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: /tmp/krb5cc_1494_sM11PG
is owned by 1494, not 0
Feb  8 09:51:46 trog cifs.upcall: handle_krb5_mech: getting service
ticket for smb.physics.wisc.edu
Feb  8 09:51:46 trog cifs.upcall: handle_krb5_mech: obtained service ticket
Feb  8 09:51:46 trog cifs.upcall: Exit status 0
Feb  8 09:51:46 trog cifs.upcall: key description:
cifs.spnego;0;0;39010000;ver=0x2;host=smb.physics.wisc.edu;ip4=128.104.160.17;sec=krb5;uid=0x0;creduid=0x0;user=smbadmin
at PHYSICS.WISC.EDU;pid=0x6bd0
Feb  8 09:51:46 trog cifs.upcall: ver=2
Feb  8 09:51:46 trog cifs.upcall: host=smb.physics.wisc.edu
Feb  8 09:51:46 trog cifs.upcall: ip=128.104.160.17
Feb  8 09:51:46 trog cifs.upcall: sec=1
Feb  8 09:51:46 trog cifs.upcall: uid=0
Feb  8 09:51:46 trog cifs.upcall: creduid=0
Feb  8 09:51:46 trog cifs.upcall: user=smbadmin at PHYSICS.WISC.EDU
Feb  8 09:51:46 trog cifs.upcall: pid=27600
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: scandir error on
directory '/run/user/0': No such file or directory
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: considering /tmp/krb5cc_0
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: FILE:/tmp/krb5cc_0 is
valid ccache
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: considering
/tmp/krb5cc_1494_sM11PG
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: /tmp/krb5cc_1494_sM11PG
is owned by 1494, not 0
Feb  8 09:51:46 trog cifs.upcall: handle_krb5_mech: getting service
ticket for smb.physics.wisc.edu
Feb  8 09:51:46 trog cifs.upcall: handle_krb5_mech: obtained service ticket
Feb  8 09:51:46 trog cifs.upcall: Exit status 0
Feb  8 09:51:46 trog cifs.upcall: key description:
cifs.spnego;0;0;39010000;ver=0x2;host=smb.physics.wisc.edu;ip4=128.104.160.17;sec=krb5;uid=0x5d6;creduid=0x5d6;pid=0x6725
Feb  8 09:51:46 trog cifs.upcall: ver=2
Feb  8 09:51:46 trog cifs.upcall: host=smb.physics.wisc.edu
Feb  8 09:51:46 trog cifs.upcall: ip=128.104.160.17
Feb  8 09:51:46 trog cifs.upcall: sec=1
Feb  8 09:51:46 trog cifs.upcall: uid=1494
Feb  8 09:51:46 trog cifs.upcall: creduid=1494
Feb  8 09:51:46 trog cifs.upcall: pid=26405
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: considering /tmp/krb5cc_0
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: /tmp/krb5cc_0 is owned
by 0, not 1494
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc: considering
/tmp/krb5cc_1494_sM11PG
Feb  8 09:51:46 trog cifs.upcall: find_krb5_cc:
FILE:/tmp/krb5cc_1494_sM11PG is valid ccache
Feb  8 09:51:46 trog cifs.upcall: handle_krb5_mech: getting service
ticket for smb.physics.wisc.edu
Feb  8 09:51:46 trog cifs.upcall: handle_krb5_mech: obtained service ticket
Feb  8 09:51:46 trog cifs.upcall: Exit status 0


NON-WORKING
cifs-utils v 6.6-5
eb  8 09:48:14 trog cifs.upcall: key description:
cifs.spnego;0;0;39010000;ver=0x2;host=smb.physics.wisc.edu;ip4=128.104.160.17;sec=krb5;uid=0x0;creduid=0x0;user=smbadmin
at PHYSICS.WISC.EDU;pid=0x67d2
Feb  8 09:48:14 trog cifs.upcall: ver=2
Feb  8 09:48:14 trog cifs.upcall: host=smb.physics.wisc.edu
Feb  8 09:48:14 trog cifs.upcall: ip=128.104.160.17
Feb  8 09:48:14 trog cifs.upcall: sec=1
Feb  8 09:48:14 trog cifs.upcall: uid=0
Feb  8 09:48:14 trog cifs.upcall: creduid=0
Feb  8 09:48:14 trog cifs.upcall: user=smbadmin at PHYSICS.WISC.EDU
Feb  8 09:48:14 trog cifs.upcall: pid=26578
Feb  8 09:48:14 trog cifs.upcall: get_tgt_time: unable to get principal
Feb  8 09:48:14 trog cifs.upcall: handle_krb5_mech: getting service
ticket for smb.physics.wisc.edu
Feb  8 09:48:14 trog cifs.upcall: handle_krb5_mech: obtained service ticket
Feb  8 09:48:14 trog cifs.upcall: Exit status 0
Feb  8 09:48:14 trog cifs.upcall: key description:
cifs.spnego;0;0;39010000;ver=0x2;host=smb.physics.wisc.edu;ip4=128.104.160.17;sec=krb5;uid=0x0;creduid=0x0;user=smbadmin
at PHYSICS.WISC.EDU;pid=0x67d2
Feb  8 09:48:14 trog cifs.upcall: ver=2
Feb  8 09:48:14 trog cifs.upcall: host=smb.physics.wisc.edu
Feb  8 09:48:14 trog cifs.upcall: ip=128.104.160.17
Feb  8 09:48:14 trog cifs.upcall: sec=1
Feb  8 09:48:14 trog cifs.upcall: uid=0
Feb  8 09:48:14 trog cifs.upcall: creduid=0
Feb  8 09:48:14 trog cifs.upcall: user=smbadmin at PHYSICS.WISC.EDU
Feb  8 09:48:14 trog cifs.upcall: pid=26578
Feb  8 09:48:14 trog cifs.upcall: handle_krb5_mech: getting service
ticket for smb.physics.wisc.edu
Feb  8 09:48:14 trog cifs.upcall: handle_krb5_mech: obtained service ticket
Feb  8 09:48:14 trog cifs.upcall: Exit status 0
Feb  8 09:48:14 trog cifs.upcall: key description:
cifs.spnego;0;0;39010000;ver=0x2;host=smb.physics.wisc.edu;ip4=128.104.160.17;sec=krb5;uid=0x5d6;creduid=0x5d6;pid=0x6725
Feb  8 09:48:14 trog cifs.upcall: ver=2
Feb  8 09:48:14 trog cifs.upcall: host=smb.physics.wisc.edu
Feb  8 09:48:14 trog kernel: [223018.425633] CIFS VFS: Send error in
SessSetup = -126
Feb  8 09:48:14 trog cifs.upcall: ip=128.104.160.17
Feb  8 09:48:14 trog cifs.upcall: sec=1
Feb  8 09:48:14 trog cifs.upcall: uid=1494
Feb  8 09:48:14 trog cifs.upcall: creduid=1494
Feb  8 09:48:14 trog cifs.upcall: pid=26405
Feb  8 09:48:14 trog cifs.upcall: get_tgt_time: unable to get principal
Feb  8 09:48:14 trog cifs.upcall: Exit status 1

Aurélien Aptel

2017-Feb-09 13:15 UTC

head link

[Samba] cifs-utils: regression in (mulituser?) mounting 'CIFS VFS: Send error in SessSetup = -126'

Chad William Seys via samba <samba at lists.samba.org>
writes:>    But when cifs-utils 6.4-1 is installed (from jessie) the different
> user can access as expect.  AFAIK there are no other differences besides
> the cifs-utils version.
Not counting any distro-specific patches it seems cifs.upcall only had 5
commits affecting it between these 2 releases:

  $ git log  --pretty=oneline cifs-utils-6.6...cifs-utils-6.4 cifs.upcall.c
  7852bec cifs.upcall: stop passing around ccache name strings
  39dbb7b cifs.upcall: make get_tgt_time take a ccache arg
  3db6b3a cifs.upcall: remove KRB5_TC_OPENCLOSE
  a3743af cifs.upcall: make the krb5_context a static global variable
  9be6e88 cifs.upcall: use krb5 routines to get default ccname

It seems the way cached credentials are searched changed, which your logs
show if you diff them:

  uid=0
  creduid=0
  user=smbadmin at PHYSICS.WISC.EDU
 -pid=27600
 -find_krb5_cc: scandir error on directory '/run/user/0': No such file
or directory
 -find_krb5_cc: considering /tmp/krb5cc_0
 -find_krb5_cc: FILE:/tmp/krb5cc_0 is valid ccache
 -find_krb5_cc: considering /tmp/krb5cc_1494_sM11PG
 -find_krb5_cc: /tmp/krb5cc_1494_sM11PG is owned by 1494, not 0
 +pid=26578
 +get_tgt_time: unable to get principal
  handle_krb5_mech: getting service ticket for smb.physics.wisc.edu
  handle_krb5_mech: obtained service ticket
  Exit status 0

That "get_tgt_time: unable to get principal" message looks like it
could
be related to "39dbb7b cifs.upcall: make get_tgt_time take a ccache
arg". Since you can easily reproduce the problem, if I were you I would
try to find the bad commits between those 5.

-- 
Aurélien Aptel / SUSE Labs Samba Team
GPG: 1839 CB5F 9F5B FB9B AA97  8C99 03C8 A49B 521B D5D3
SUSE Linux GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)

Chad William Seys

2017-Feb-09 19:23 UTC

head link

[Samba] cifs-utils: regression in (mulituser?) mounting 'CIFS VFS: Send error in SessSetup = -126'

Hi Aurélien,
   Thanks for the idea!
For Debian packages:
   6.4-1 works
   6.5-1 works
   6.5-2 works
   6.6-1 fails
   6.6-5 fails

So looks like something changed from 6.5 to 6.6...
When I have time I'll figure out how to compile the upcall binary.

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