[gpfsug-discuss] Snapshots / Windows previous versions
Sobey, Richard A
r.sobey at imperial.ac.uk
Wed Jul 6 13:22:53 BST 2016
Thanks Daniel – sorry to be dense, but does this indicate working as intended, or a bug? I assume the former. So, the question still remains how has this suddenly broken, when:
[root at server ict]# mmgetacl -k nfs4 .snapshots/
.snapshots/: Operation not permitted
…appears to be the correct output and is consistent with someone else’s GPFS cluster where it is working.
Cheers
Richard
From: gpfsug-discuss-bounces at spectrumscale.org [mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Daniel Kidger
Sent: 06 July 2016 12:51
To: gpfsug-discuss at spectrumscale.org
Cc: gpfsug-discuss at spectrumscale.org
Subject: Re: [gpfsug-discuss] Snapshots / Windows previous versions
Looking at recent patches to SAMBA I see from December 2015:
https://download.samba.org/pub/samba/patches/security/samba-4.1.21-security-2015-12-16.patch,
(link found at https://bugzilla.samba.org/show_bug.cgi?id=11658 which includes the comment:
Failing that, smbd_check_access_rights should check Unix perms at that point.
)
diff --git a/source3/modules/vfs_shadow_copy2.c b/source3/modules/vfs_shadow_copy2.c
index fca05cf..07e2f8a 100644
--- a/source3/modules/vfs_shadow_copy2.c
+++ b/source3/modules/vfs_shadow_copy2.c
@@ -30,6 +30,7 @@
*/
#include "includes.h"
+#include "smbd/smbd.h"
#include "system/filesys.h"
#include "include/ntioctl.h"
#include <ccan/hash/hash.h>
@@ -1138,6 +1139,42 @@ static char *have_snapdir(struct vfs_handle_struct *handle,
return NULL;
}
+static bool check_access_snapdir(struct vfs_handle_struct *handle,
+ const char *path)
+{
+ struct smb_filename smb_fname;
+ int ret;
+ NTSTATUS status;
+
+ ZERO_STRUCT(smb_fname);
+ smb_fname.base_name = talloc_asprintf(talloc_tos(),
+ "%s",
+ path);
+ if (smb_fname.base_name == NULL) {
+ return false;
+ }
+
+ ret = SMB_VFS_NEXT_STAT(handle, &smb_fname);
+ if (ret != 0 || !S_ISDIR(smb_fname.st.st_ex_mode)) {
+ TALLOC_FREE(smb_fname.base_name);
+ return false;
+ }
+
+ status = smbd_check_access_rights(handle->conn,
+ &smb_fname,
+ false,
+ SEC_DIR_LIST);
+ if (!NT_STATUS_IS_OK(status)) {
+ DEBUG(0,("user does not have list permission "
+ "on snapdir %s\n",
+ smb_fname.base_name));
+ TALLOC_FREE(smb_fname.base_name);
+ return false;
+ }
+ TALLOC_FREE(smb_fname.base_name);
+ return true;
+}
+
Daniel
Dr Daniel Kidger
IBM Technical Sales Specialist
Software Defined Solution Sales
+44-07818 522 266
daniel.kidger at uk.ibm.com<mailto:daniel.kidger at uk.ibm.com>
----- Original message -----
From: "Sobey, Richard A" <r.sobey at imperial.ac.uk<mailto:r.sobey at imperial.ac.uk>>
Sent by: gpfsug-discuss-bounces at spectrumscale.org<mailto:gpfsug-discuss-bounces at spectrumscale.org>
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org<mailto:gpfsug-discuss at spectrumscale.org>>
Cc:
Subject: Re: [gpfsug-discuss] Snapshots / Windows previous versions
Date: Wed, Jul 6, 2016 10:55 AM
Sure. It might be easier if I just post the entire smb.conf:
[global]
netbios name = store
workgroup = IC
security = ads
realm = IC.AC.UK
kerberos method = secrets and keytab
vfs objects = shadow_copy2 syncops gpfs fileid
ea support = yes
store dos attributes = yes
map readonly = no
map archive = no
map system = no
map hidden = no
unix extensions = no
allocation roundup size = 1048576
disable netbios = yes
smb ports = 445
# server signing = mandatory
template shell = /bin/bash
interfaces = bond2 lo bond0
allow trusted domains = no
printing = bsd
printcap name = /dev/null
load printers = no
disable spoolss = yes
idmap config IC : default = yes
idmap config IC : cache time = 180
idmap config IC : backend = ad
idmap config IC : schema_mode = rfc2307
idmap config IC : range = 500 - 2000000
idmap config * : range = 3000000 - 3500000
idmap config * : backend = tdb2
winbind refresh tickets = yes
winbind nss info = rfc2307
winbind use default domain = true
winbind offline logon = true
winbind separator = /
winbind enum users = true
winbind enum groups = true
winbind nested groups = yes
winbind expand groups = 2
winbind max clients = 10000
clustering = yes
ctdbd socket = /tmp/ctdb.socket
gpfs:sharemodes = yes
gpfs:winattr = yes
gpfs:leases = yes
gpfs:dfreequota = yes
# nfs4:mode = special
# nfs4:chown = no
nfs4:chown = yes
nfs4:mode = simple
nfs4:acedup = merge
fileid:algorithm = fsname
force unknown acl user = yes
shadow:snapdir = .snapshots
shadow:fixinodes = yes
shadow:snapdirseverywhere = yes
shadow:sort = desc
syncops:onclose = no
syncops:onmeta = no
kernel oplocks = yes
level2 oplocks = yes
oplocks = yes
notify:inotify = no
wide links = no
async smb echo handler = yes
smbd:backgroundqueue = False
use sendfile = no
dmapi support = yes
aio write size = 1
aio read size = 1
enable core files = no
#debug logging
log level = 2
log file = /var/log/samba.%m
max log size = 1024
debug timestamp = yes
[IC]
comment = Unified Group Space Area
path = /gpfs/prd/groupspace/ic
public = no
read only = no
valid users = "@domain users"
From: gpfsug-discuss-bounces at spectrumscale.org<mailto:gpfsug-discuss-bounces at spectrumscale.org> [mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Barry Evans
Sent: 06 July 2016 10:47
To: gpfsug-discuss at spectrumscale.org<mailto:gpfsug-discuss at spectrumscale.org>
Subject: Re: [gpfsug-discuss] Snapshots / Windows previous versions
Can you cut/paste your full VFS options for gpfs and shadow copy from smb.conf?
On 06/07/2016 10:37, Sobey, Richard A wrote:
Quick followup on this. Doing some more samba debugging (i.e. increasing log levels!) and come up with the following:
[2016/07/06 10:07:35.602080, 3] ../source3/smbd/vfs.c:1322(check_reduced_name)
check_reduced_name: admin/ict/serviceoperations/slough_project/Slough_Layout reduced to /gpfs/prd/groupspace/ic/admin/ict/serviceoperations/slough_project/Slough_Layout
[2016/07/06 10:07:35.611881, 3] ../source3/smbd/dosmode.c:196(unix_mode)
unix_mode(admin/ict/serviceoperations/slough_project/Slough_Layout) returning 0644
[2016/07/06 10:07:35.613374, 0] ../source3/modules/vfs_shadow_copy2.c:1211(check_access_snapdir)
user does not have list permission on snapdir /gpfs/prd/groupspace/ic/admin/ict/.snapshots
[2016/07/06 10:07:35.613416, 0] ../source3/modules/vfs_shadow_copy2.c:1380(shadow_copy2_get_shadow_copy_data)
access denied on listing snapdir /gpfs/prd/groupspace/ic/admin/ict/.snapshots
[2016/07/06 10:07:35.613434, 0] ../source3/modules/vfs_default.c:1145(vfswrap_fsctl)
FSCTL_GET_SHADOW_COPY_DATA: connectpath /gpfs/prd/groupspace/ic, failed - NT_STATUS_ACCESS_DENIED.
[2016/07/06 10:07:47.648557, 3] ../source3/smbd/service.c:1138(close_cnum)
155.198.55.14 (ipv4:155.198.55.14:51298) closed connection to service IPC$
Any takers? I cannot run mmgetacl on the .snapshots folder at all, as root. A snapshot I just created to make sure I had full control on the folder: (39367 is me, I didn’t run this command on a CTDB node so the UID mapping isn’t working).
[root at icgpfs01 .snapshots]# mmgetacl -k nfs4 @GMT-2016.07.06-08.00.06
#NFSv4 ACL
#owner:root
#group:root
group:74036:r-x-:allow:FileInherit:DirInherit:Inherited
(X)READ/LIST (-)WRITE/CREATE (-)MKDIR (X)SYNCHRONIZE (X)READ_ACL (X)READ_ATTR (X)READ_NAMED
(-)DELETE (-)DELETE_CHILD (-)CHOWN (X)EXEC/SEARCH (-)WRITE_ACL (-)WRITE_ATTR (-)WRITE_NAMED
user:39367:rwxc:allow:FileInherit:DirInherit:Inherited
(X)READ/LIST (X)WRITE/CREATE (X)MKDIR (X)SYNCHRONIZE (X)READ_ACL (X)READ_ATTR (X)READ_NAMED
(X)DELETE (X)DELETE_CHILD (X)CHOWN (X)EXEC/SEARCH (X)WRITE_ACL (X)WRITE_ATTR (X)WRITE_NAMED
From: gpfsug-discuss-bounces at spectrumscale.org<mailto:gpfsug-discuss-bounces at spectrumscale.org> [mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Sobey, Richard A
Sent: 20 June 2016 16:03
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org><mailto:gpfsug-discuss at spectrumscale.org>
Subject: Re: [gpfsug-discuss] Snapshots / Windows previous versions
Thanks Kevin. We are upgrading to GPFS 4.2 and CES in a few weeks but our customers have come to like previous versions and indeed it is sort of a selling point for us.
Samba is the only thing we’ve changed recently after the badlock debacle so I’m tempted to blame that, but who knows.
If (when) I find out I’ll let everyone know.
Richard
From: gpfsug-discuss-bounces at spectrumscale.org<mailto:gpfsug-discuss-bounces at spectrumscale.org> [mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Buterbaugh, Kevin L
Sent: 20 June 2016 15:56
To: gpfsug main discussion list <gpfsug-discuss at spectrumscale.org><mailto:gpfsug-discuss at spectrumscale.org>
Subject: Re: [gpfsug-discuss] Snapshots / Windows previous versions
Hi Richard,
I can’t answer your question but I can tell you that we have experienced either the exact same thing you are or something very similar. It occurred for us after upgrading from GPFS 3.5 to 4.1.0.8 and it persists even after upgraded to GPFS 4.2.0.3 and the very latest sernet-samba.
And to be clear, when we upgraded from GPFS 3.5 to 4.1 we did *not* upgrade SAMBA versions at that time. Therefore, I believe that something changed in GPFS. That doesn’t mean it’s GPFS’ fault, of course. SAMBA may have been relying on a bug<ctrl-h><ctrl-h><ctrl-h>undocumented feature in GPFS that IBM fixed for all I know, and I’m obviously speculating here.
The problem we see is that the .snapshots directory in each folder can be cd’d to but is empty. The snapshots are all there, however, if you:
cd /<mount point of fs>/.snapshots/<data and time snapshot was taken>/rest/of/path/to/folder/in/question
This obviously prevents users from being able to do their own recovery of files unless you do something like what you describe, which we are unwilling to do for security reasons. We have a ticket open with DDN…
Kevin
On Jun 20, 2016, at 8:45 AM, Sobey, Richard A <r.sobey at imperial.ac.uk<mailto:r.sobey at imperial.ac.uk>> wrote:
Hi all
Can someone clarify if the ability for Windows to view snapshots as Previous Versions is exposed by SAMBA or GPFS? Basically, if suddenly my users cannot restore files from snapshots over a CIFS share, where should I be looking?
I don’t know when this problem occurred, but within the last few weeks certainly our users with full control over their data now see no previous versions available, but if we export their fileset and set “force user = root” all the snapshots are available.
I think the answer is SAMBA, right? We’re running GPFS 3.5 and sernet-samba 4.2.9.
Many thanks
Richard
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