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mirror of https://github.com/samba-team/samba.git synced 2025-02-09 09:57:48 +03:00

8872 Commits

Author SHA1 Message Date
Gary Lockyer
3bc5685445 rpc: Always supply both the remote and local address to the auth subsystem
This ensures that gensec, and then the NTLM auth subsystem under it, always gets the
remote and local address pointers for potential logging.

The local address allows us to know which interface an authentication is on

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Pair-Programmed-by: Gary Lockyer <gary@catalyst.net.nz>
Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
2017-03-29 02:37:27 +02:00
Andrew Bartlett
85536c1ff3 auth: Always supply both the remote and local address to the auth subsystem
This ensures that gensec, and then the NTLM auth subsystem under it, always gets the
remote and local address pointers for potential logging.

The local address allows us to know which interface an authentication is on

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Pair-Programmed-by: Gary Lockyer <gary@catalyst.net.nz>
Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
2017-03-29 02:37:26 +02:00
Andrew Bartlett
ea3f00f2b5 auth: Add "auth_description" to allow logs to distinguish simple bind (etc)
This will allow the authentication log to indicate clearly how the password was
supplied to the server.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Pair-Programmed-by: Gary Lockyer <gary@catalyst.net.nz>
Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
2017-03-29 02:37:26 +02:00
Andrew Bartlett
c048918959 auth: Fill in user_info->service_description from all callers
This will allow the logging code to make clear which protocol an authentication was for.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Pair-Programmed-by: Gary Lockyer <gary@catalyst.net.nz>
Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
2017-03-29 02:37:25 +02:00
Andrew Bartlett
d82ac32eb7 s3-auth: Pass service_description into gensec via auth_generic_prepare()
This allows the GENSEC service description to be set from the various callers
that go via this function.

The RPC service description is the name of the interface from the IDL.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Pair-Programmed-by: Gary Lockyer <gary@catalyst.net.nz>
Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
2017-03-29 02:37:25 +02:00
Ralph Boehme
0622811fab s3/smbd: optimize copy-chunk by merging chunks if possible
Merge chunks with adjacent ranges. This results in fewer IO requests for
the typical server-side file copy usecase: just one 16 MB copy instead
of sixteen 1 MB.

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-28 17:45:20 +02:00
Ralph Boehme
8bc94a9f9d s3/smbd: implement a serializing async copy-chunk loop
Later commits will make the low level copy-chunk implementation async
using a thread pool. That means the individual chunks may be scheduled
and copied out-of-order at the low level.

According to conversation with MS Dochelp, a server implementation
must process individual chunks in order.

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-28 17:45:20 +02:00
Ralph Boehme
6314dda7fe s3/smbd: move cc_copy into fsctl_srv_copychunk_state
No change, in behaviour, just preperational stuff to unroll the core
copy loop.

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-28 17:45:20 +02:00
Ralph Boehme
dc4bd3f751 s3/smbd: move copychunk ioctl limits to IDL
This will be needed in the next commit in vfs_default.

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-28 17:45:20 +02:00
Jeremy Allison
e182a4d39e s3: smbd: Fix "follow symlink = no" regression part 2.
Use the cwd_name parameter to reconstruct the original
client name for symlink testing.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12721

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
2017-03-28 13:20:26 +02:00
Jeremy Allison
83e30cb488 s3: smbd: Fix "follow symlink = no" regression part 2.
Add an extra paramter to cwd_name to check_reduced_name().

If cwd_name == NULL then fname is a client given path relative
to the root path of the share.

If cwd_name != NULL then fname is a client given path relative
to cwd_name. cwd_name is relative to the root path of the share.

Not yet used, logic added in the next commit.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12721

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
2017-03-28 13:20:26 +02:00
Jeremy Allison
ae17bebd25 s3: smbd: Fix incorrect logic exposed by fix for the security bug 12496 (CVE-2017-2619).
In a UNIX filesystem, the names "." and ".." by definition can *never*
be symlinks - they are already reserved names.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12721

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-28 03:04:17 +02:00
Uri Simchoni
6711522e1e smbd: add zero_file_id flag
This flag instructs the SMB layer to report a zero on-disk
file identifier.

According to [MS-SMB2] 3.3.5.9.9, the reported on-disk file ID
SHOULD be unique. However, macOS clients seem to expect it to be
unique over time as well, like the HFS+ CNID. Reporting a file ID
of 0 seems to instruct the Mac client not to trust the server-reported
file ID.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12715

Signed-off-by: Uri Simchoni <uri@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
2017-03-26 19:42:16 +02:00
Jeremy Allison
294a1a8374 CVE-2017-2619: s3: smbd: Use the new non_widelink_open() function.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>

Autobuild-User(master): Karolin Seeger <kseeger@samba.org>
Autobuild-Date(master): Thu Mar 23 22:55:04 CET 2017 on sn-devel-144
2017-03-23 22:55:04 +01:00
Jeremy Allison
4301505d97 CVE-2017-2619: s3: smbd: Add the core functions to prevent symlink open races.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Jeremy Allison
592e7fa67b CVE-2017-2619: s3: smbd: Move special handling of symlink errno's into a utility function.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Jeremy Allison
6ff5f0a75a CVE-2017-2619: s3: smbd: Remove O_NOFOLLOW guards. We insist on O_NOFOLLOW existing.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Jeremy Allison
49ed0b01d1 CVE-2017-2619: s3: smbd: Correctly fallback to open_dir_safely if FDOPENDIR not supported on system.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Jeremy Allison
f6dfdf7d31 CVE-2017-2619: s3: smbd: Move the reference counting and destructor setup to just before retuning success.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Jeremy Allison
e68e73b8d3 CVE-2017-2619: s3: smbd: OpenDir_fsp() - Fix memory leak on error.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Jeremy Allison
86f15237a1 CVE-2017-2619: s3: smbd: OpenDir_fsp() use early returns.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Jeremy Allison
05a9898dda CVE-2017-2619: s3: smbd: Create and use open_dir_safely(). Use from OpenDir().
Hardens OpenDir against TOC/TOU races.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Jeremy Allison
682d597ee3 CVE-2017-2619: s3: smbd: Opendir_internal() early return if SMB_VFS_OPENDIR failed.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Jeremy Allison
3461518027 CVE-2017-2619: s3: smbd: Create wrapper function for OpenDir in preparation for making robust.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Ralph Boehme
47b6b6f8f5 CVE-2017-2619: s3/smbd: re-open directory after dptr_CloseDir()
dptr_CloseDir() will close and invalidate the fsp's file descriptor, we
have to reopen it.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=12496

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Uri Simchoni <uri@samba.org>
2017-03-23 19:10:19 +01:00
Aurelien Aptel
1eaafead1e s3:smbd: exit early if srv_send_smb fails
coverity fix.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Ralph Böhme <slow@samba.org>
2017-03-16 20:30:19 +01:00
Jeremy Allison
125c78ad0b s3: locking: Move two leases functions into a new file.
map_oplock_to_lease_type(), fsp_lease_type().

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12628

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
2017-03-15 16:14:08 +01:00
Ralph Boehme
d3e2e41995 s3/smbd: add my copyright to open.c
Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-10 03:28:26 +01:00
Ralph Boehme
b35a296a27 s3/smbd: fix deferred open with streams and kernel oplocks
I noticed smbd can get stuck in an open() call with kernel oplocks
enabled and named streams (provided by vfs_streams_xattr):

- client opens a file and with an exclusive oplock

- client starts writing to the file

- client opens an existing stream of the file

- the smbd process gets stuck in an open()

What happens is:

we had setup a locking.tdb record watch in defer_open(), the watch was
triggered, we reattempted the open and got stuck in a blocking open
because the oplock holder (ourselves) hadn't given up the oplock yet.

Cf e576bf5310bc9de9686a71539e9a1b60b4fba5cc for the commit that added
the kernel oplock retry logic. tldr: with kernel oplocks the first open
is non-blocking, but the second one is blocking.

Detailed analysis follows.

When opening a named stream of a file, Samba internally opens the
underlying "base" file first. This internal open of the basefile suceeds
and does *not* trigger an oplock break (because it is an internal open
that doesn't call open() at all) but it is added as an entry to the
locking.tdb record of the file.

Next, the stream open ends up in streams_xattr where a non-blocking
open() on the base file is called. This open fails with EWOULDBLOCK
because we have another fd with a kernel oplock on the file.

So we call defer_open() which sets up a watch on the locking.tdb record.

In the subsequent error unwinding code in open_file_ntcreate() and
callers we close the internal open file handle of the basefile which
also removes the entry from the locking.tdb record and so *changes the
record*.

This fires the record watch and in the callback defer_open_done() we
don't check whether the condition (oplock gone) we're interested in is
actually met. The callback blindly reschedules the open request with
schedule_deferred_open_message_smb().

schedule_deferred_open_message_smb() schedules an immediate tevent event
which has precedence over the IPC fd events in messaging, so the open is
always (!) reattempted before processing the oplock break message.

As explained above, this second open will be a blocking one so we get
stuck in a blocking open.

It doesn't help to make all opens non-blocking, that would just result
in a busy loop failing the open, as we never process the oplock break
message (remember, schedule_deferred_open_message_smb() used immediate
tevent events).

To fix this we must add some logic to the record watch callback to check
whether the record watch was done for a kernel oplock file and if yes,
check if the oplock state changed. If not, simply reschedule the
deferred open and keep waiting.

This logic is only needed for kernel oplocks, not for Samba-level
oplocks, because there's no risk of deadlocking, the worst that can
happen is a rescheduled open that fails again in the oplock checks and
gets deferred again.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=7537

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-10 03:28:26 +01:00
Ralph Boehme
1a6c82e5d5 s3/smbd: all callers of defer_open() pass a lck
No change in behaviour. Update the function comment explaining how it
works and relies on lck for a record watch.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=7537

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-10 03:28:26 +01:00
Ralph Boehme
7fa2f11594 s3/smbd: remove async_open arg from defer_open()
All remaining callers pass false.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=7537

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-10 03:28:25 +01:00
Ralph Boehme
ad8c36125f s3/smbd: fix schedule_async_open() timer
schedule_async_open() was calling defer_open with sharemode lock = NULL,
as a result there was never an active 20 s timeout.

This has been broken since the commits in

$ git log --reverse -p -10 8283fd0e0090ed12b0b12d5acb550642d621b026

Just roll our own deferred record instead of calling defer_open() and
also set up timer that, as a last resort, catches stuck opens and just
exits for now.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=7537

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-10 03:28:25 +01:00
Ralph Boehme
beaba62228 s3/smbd: add and use retry_open() instead of defer_open() in two places
Add a new function that does an immediate open rescheduling.

The first deferred open this commit changes was never scheduled, as the
scheduling relies on a timeout of the watch on the sharemode lock.

This has been broken since the commits in

$ git log --reverse -p -10 8283fd0e0090ed12b0b12d5acb550642d621b026

That patchset added the dbwrap watch record logic to defer_open() and
removed the timers.

I'm doing this mainly to untangle the defer_open() logic which is
complicated by the lck arg.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=7537

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-10 03:28:25 +01:00
Ralph Boehme
b17ff9b181 s3/smbd: simplify defer_open()
Add a helper function deferred_open_record_create() that creates a
deferred_open_record and let all callers pass all needed arguments
individually.

While we're at it, enhance the debug message in defer_open() to print
all variables.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=7537

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-10 03:28:25 +01:00
Ralph Boehme
8580adc1d9 s3/smbd: req is already validated at the beginning of open_file_ntcreate()
req can't be NULL because the if condition surrounding this code checks
!(oplock_request & INTERNAL_OPEN_ONLY).

Bug: https://bugzilla.samba.org/show_bug.cgi?id=7537

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-10 03:28:25 +01:00
Ralph Boehme
f5631f6b35 s3/smbd: add comments and some reformatting to open_file_ntcreate()
No change in behaviour.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=7537

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-10 03:28:25 +01:00
Ralph Boehme
6924e72ade s3/smbd: add const to get_lease_type() args
Bug: https://bugzilla.samba.org/show_bug.cgi?id=7537

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-10 03:28:25 +01:00
Volker Lendecke
cf9acf9a3d smbd: Do an early exit on negprot failure
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12610

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Ralph Böhme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-03 02:24:09 +01:00
Jeremy Allison
1e0c79ddb3 s3: smbd: Restart reading the incoming SMB2 fd when the send queue is drained.
When the send queue grows greater than xconn->smb2.credits.max/16,
smbd_smb2_request_next_incoming() doesn't allocate a new request in state->req.

After smbd_smb2_io_handler() is called, it marks the fd not readable as
state->req == NULL, and never marks it readable again.

Fix by calling smbd_smb2_request_next_incoming() to restart
reads inside smbd_smb2_flush_send_queue() which drains the
send queue.

Reported by <chen.yehua@h3c.com>

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12608

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>

Autobuild-User(master): Ralph Böhme <slow@samba.org>
Autobuild-Date(master): Fri Mar  3 02:23:20 CET 2017 on sn-devel-144
2017-03-03 02:23:20 +01:00
Uri Simchoni
4bfd27b077 smbd: remove coupling between get_ea_names_from_file() and "ea support"
The "ea support" configuration variable determines whether smbd
should attempt to manipulate extended attributes via SMB protocol.
It does not pertain to the underlying storage and its support for
extended attributes.

get_ea_names_from_file() is being used also by vfs_streams_xattr -
a module which has nothing to do with client-visible extended
attributes. As such, vfs_streams_xattr should be able to operate
irrespective of the value of "ea support".

This patch moves the check for ea support to the callers.

Signed-off-by: Uri Simchoni <uri@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
2017-03-02 22:30:23 +01:00
Uri Simchoni
fb95985a03 smbd: get_ea_list_from_file_path() - remove a duplicate statement
Signed-off-by: Uri Simchoni <uri@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
2017-03-02 22:30:23 +01:00
Uri Simchoni
abd845082e smbd: refuse_symlink() - do not fail if the file does not exist
If the file does not exist, it is not a symlink. Current callers
use this function to see if extended attributes can be set / fetched.
Allow them to try and leave the error code at the discretion of the
VFS.

Signed-off-by: Uri Simchoni <uri@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
2017-03-02 22:30:23 +01:00
Volker Lendecke
cc3417549c posix_acls: Use talloc_zero_array
This is a slight change in behaviour: We now also zero out
the space for num_profile_acls.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-01 20:33:18 +01:00
Volker Lendecke
2dc369feac posix_acls: Do a *bit* of reformatting
Makes the next commit a bit more obvious to me

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2017-03-01 20:33:17 +01:00
Aurelien Aptel
73180972db s3/smbd: allow GET_DFS_REFERRAL fsctl on any smb2 connexion
This FSCTL should work on any non-IPC share.

According to [MS-SMB2]
> 3.2.4.20.3 Application Requests DFS Referral Information:
>  The client MUST search for an existing Session and TreeConnect to any
>  share on the server identified by ServerName for the user identified by
>  UserCredentials. If no Session and TreeConnect are found, the client
>  MUST establish a new Session and TreeConnect to IPC$ on the target
>  server as described in section 3.2.4.2 using the supplied ServerName and
>  UserCredentials.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: David Disseldorp <ddiss@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Sat Feb 25 02:38:28 CET 2017 on sn-devel-144
2017-02-25 02:38:28 +01:00
Chris Lamb
43421364ac Correct "allready" typos.
Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
2017-02-22 08:26:24 +01:00
Chris Lamb
98453b0dbb Correct "succeded" typos.
Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
2017-02-22 08:26:23 +01:00
Chris Lamb
1134f4f177 Correct "cleint" typos.
Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
2017-02-22 08:26:23 +01:00
Chris Lamb
bca0d8ee67 Correct "defered" typos.
Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
2017-02-22 08:26:23 +01:00
Jeremy Allison
10c3e39230 s3: smbd: Don't loop infinitely on bad-symlink resolution.
In the FILE_OPEN_IF case we have O_CREAT, but not
O_EXCL. Previously we went into a loop trying first
~(O_CREAT|O_EXCL), and if that returned ENOENT
try (O_CREAT|O_EXCL). We kept looping indefinately
until we got an error, or the file was created or
opened.

The big problem here is dangling symlinks. Opening
without O_NOFOLLOW means both bad symlink
and missing path return -1, ENOENT from open(). As POSIX
is pathname based it's not possible to tell
the difference between these two cases in a
non-racy way, so change to try only two attempts before
giving up.

We don't have this problem for the O_NOFOLLOW
case as we just return NT_STATUS_OBJECT_PATH_NOT_FOUND
mapped from the ELOOP POSIX error and immediately
returned.

Unroll the loop logic to two tries instead.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12572

Pair-programmed-with: Ralph Boehme <slow@samba.org>

Signed-off-by: Jeremy Allison <jra@samba.org>
Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
2017-02-16 18:14:20 +01:00