Commit Graph

3547 Commits

Author SHA1 Message Date
Linus Torvalds
dcf23ac3e8 locks: reinstate locks_delete_block optimization
There is measurable performance impact in some synthetic tests due to
commit 6d390e4b5d (locks: fix a potential use-after-free problem when
wakeup a waiter). Fix the race condition instead by clearing the
fl_blocker pointer after the wake_up, using explicit acquire/release
semantics.

This does mean that we can no longer use the clearing of fl_blocker as
the wait condition, so switch the waiters over to checking whether the
fl_blocked_member list_head is empty.

Reviewed-by: yangerkun <yangerkun@huawei.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Fixes: 6d390e4b5d (locks: fix a potential use-after-free problem when wakeup a waiter)
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-18 13:03:38 -07:00
Murphy Zhou
979a2665eb CIFS: fiemap: do not return EINVAL if get nothing
If we call fiemap on a truncated file with none blocks allocated,
it makes sense we get nothing from this call. No output means
no blocks have been counted, but the call succeeded. It's a valid
response.

Simple example reproducer:
xfs_io -f 'truncate 2M' -c 'fiemap -v' /cifssch/testfile
xfs_io: ioctl(FS_IOC_FIEMAP) ["/cifssch/testfile"]: Invalid argument

Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org>
2020-03-17 13:27:06 -05:00
Shyam Prasad N
1be1fa42eb CIFS: Increment num_remote_opens stats counter even in case of smb2_query_dir_first
The num_remote_opens counter keeps track of the number of open files which must be
maintained by the server at any point. This is a per-tree-connect counter, and the value
of this counter gets displayed in the /proc/fs/cifs/Stats output as a following...

Open files: 0 total (local), 1 open on server
                             ^^^^^^^^^^^^^^^^
As a thumb-rule, we want to increment this counter for each open/create that we
successfully execute on the server. Similarly, we should decrement the counter when
we successfully execute a close.

In this case, an increment was being missed in case of smb2_query_dir_first,
in case of successful open. As a result, we would underflow the counter and we
could even see the counter go to negative after sufficient smb2_query_dir_first calls.

I tested the stats counter for a bunch of filesystem operations with the fix.
And it looks like the counter looks correct to me.

I also check if we missed the increments and decrements elsewhere. It does not
seem so. Few other cases where an open is done and we don't increment the counter are
the compound calls where the corresponding close is also sent in the request.

Signed-off-by: Shyam Prasad N <nspmangalore@gmail.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-03-17 13:27:03 -05:00
Dan Carpenter
39946886fc cifs: potential unintitliazed error code in cifs_getattr()
Smatch complains that "rc" could be uninitialized.

    fs/cifs/inode.c:2206 cifs_getattr() error: uninitialized symbol 'rc'.

Changing it to "return 0;" improves readability as well.

Fixes: cc1baf98c8f6 ("cifs: do not ignore the SYNC flags in getattr")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
2020-03-17 13:26:26 -05:00
Linus Torvalds
807f030b44 Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:
 "A couple of fixes for old crap in ->atomic_open() instances"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  cifs_atomic_open(): fix double-put on late allocation failure
  gfs2_atomic_open(): fix O_EXCL|O_CREAT handling on cold dcache
2020-03-12 15:51:26 -07:00
Al Viro
d9a9f4849f cifs_atomic_open(): fix double-put on late allocation failure
several iterations of ->atomic_open() calling conventions ago, we
used to need fput() if ->atomic_open() failed at some point after
successful finish_open().  Now (since 2016) it's not needed -
struct file carries enough state to make fput() work regardless
of the point in struct file lifecycle and discarding it on
failure exits in open() got unified.  Unfortunately, I'd missed
the fact that we had an instance of ->atomic_open() (cifs one)
that used to need that fput(), as well as the stale comment in
finish_open() demanding such late failure handling.  Trivially
fixed...

Fixes: fe9ec8291f "do_last(): take fput() on error after opening to out:"
Cc: stable@kernel.org # v4.7+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-03-12 18:25:20 -04:00
Joe Perches
fb4b5f1346 cifs: Use #define in cifs_dbg
All other uses of cifs_dbg use defines so change this one.

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-02-24 14:20:38 -06:00
Aurelien Aptel
86f740f2ae cifs: fix rename() by ensuring source handle opened with DELETE bit
To rename a file in SMB2 we open it with the DELETE access and do a
special SetInfo on it. If the handle is missing the DELETE bit the
server will fail the SetInfo with STATUS_ACCESS_DENIED.

We currently try to reuse any existing opened handle we have with
cifs_get_writable_path(). That function looks for handles with WRITE
access but doesn't check for DELETE, making rename() fail if it finds
a handle to reuse. Simple reproducer below.

To select handles with the DELETE bit, this patch adds a flag argument
to cifs_get_writable_path() and find_writable_file() and the existing
'bool fsuid_only' argument is converted to a flag.

The cifsFileInfo struct only stores the UNIX open mode but not the
original SMB access flags. Since the DELETE bit is not mapped in that
mode, this patch stores the access mask in cifs_fid on file open,
which is accessible from cifsFileInfo.

Simple reproducer:

	#include <stdio.h>
	#include <stdlib.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <fcntl.h>
	#include <unistd.h>
	#define E(s) perror(s), exit(1)

	int main(int argc, char *argv[])
	{
		int fd, ret;
		if (argc != 3) {
			fprintf(stderr, "Usage: %s A B\n"
			"create&open A in write mode, "
			"rename A to B, close A\n", argv[0]);
			return 0;
		}

		fd = openat(AT_FDCWD, argv[1], O_WRONLY|O_CREAT|O_SYNC, 0666);
		if (fd == -1) E("openat()");

		ret = rename(argv[1], argv[2]);
		if (ret) E("rename()");

		ret = close(fd);
		if (ret) E("close()");

		return ret;
	}

$ gcc -o bugrename bugrename.c
$ ./bugrename /mnt/a /mnt/b
rename(): Permission denied

Fixes: 8de9e86c67 ("cifs: create a helper to find a writeable handle by path name")
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
2020-02-24 14:20:38 -06:00
Steve French
ec57010acd cifs: add missing mount option to /proc/mounts
We were not displaying the mount option "signloosely" in /proc/mounts
for cifs mounts which some users found confusing recently

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2020-02-24 14:20:38 -06:00
Paulo Alcantara (SUSE)
1542552338 cifs: fix potential mismatch of UNC paths
Ensure that full_path is an UNC path that contains '\\' as delimiter,
which is required by cifs_build_devname().

The build_path_from_dentry_optional_prefix() function may return a
path with '/' as delimiter when using SMB1 UNIX extensions, for
example.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
2020-02-24 14:20:38 -06:00
Ronnie Sahlberg
fc513fac56 cifs: don't leak -EAGAIN for stat() during reconnect
If from cifs_revalidate_dentry_attr() the SMB2/QUERY_INFO call fails with an
error, such as STATUS_SESSION_EXPIRED, causing the session to be reconnected
it is possible we will leak -EAGAIN back to the application even for
system calls such as stat() where this is not a valid error.

Fix this by re-trying the operation from within cifs_revalidate_dentry_attr()
if cifs_get_inode_info*() returns -EAGAIN.

This fixes stat() and possibly also other system calls that uses
cifs_revalidate_dentry*().

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>
2020-02-24 14:20:38 -06:00
Ronnie Sahlberg
85db6b7ae6 cifs: make sure we do not overflow the max EA buffer size
RHBZ: 1752437

Before we add a new EA we should check that this will not overflow
the maximum buffer we have available to read the EAs back.
Otherwise we can get into a situation where the EAs are so big that
we can not read them back to the client and thus we can not list EAs
anymore or delete them.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
2020-02-14 11:10:24 -06:00
Steve French
2c6251ad91 cifs: enable change notification for SMB2.1 dialect
It was originally enabled only for SMB3 or later dialects, but
had requests to add it to SMB2.1 mounts as well given the
large number of systems at that dialect level.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reported-by: L Walsh <cifs@tlinx.org>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
2020-02-14 11:10:06 -06:00
Frank Sorenson
f52aa79df4 cifs: Fix mode output in debugging statements
A number of the debug statements output file or directory mode
in hex.  Change these to print using octal.

Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-02-12 22:24:26 -06:00
Petr Pavlu
3f6166aaf1 cifs: fix mount option display for sec=krb5i
Fix display for sec=krb5i which was wrongly interleaved by cruid,
resulting in string "sec=krb5,cruid=<...>i" instead of
"sec=krb5i,cruid=<...>".

Fixes: 96281b9e46 ("smb3: for kerberos mounts display the credential uid used")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-02-10 08:32:30 -06:00
Linus Torvalds
d1ea35f4cd 13 cifs/smb3 patches most from testing at the SMB3 plugfest this week
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Merge tag '5.6-rc-smb3-plugfest-patches' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "13 cifs/smb3 patches, most from testing at the SMB3 plugfest this week:

   - Important fix for multichannel and for modefromsid mounts.

   - Two reconnect fixes

   - Addition of SMB3 change notify support

   - Backup tools fix

   - A few additional minor debug improvements (tracepoints and
     additional logging found useful during testing this week)"

* tag '5.6-rc-smb3-plugfest-patches' of git://git.samba.org/sfrench/cifs-2.6:
  smb3: Add defines for new information level, FileIdInformation
  smb3: print warning once if posix context returned on open
  smb3: add one more dynamic tracepoint missing from strict fsync path
  cifs: fix mode bits from dir listing when mounted with modefromsid
  cifs: fix channel signing
  cifs: add SMB3 change notification support
  cifs: make multichannel warning more visible
  cifs: fix soft mounts hanging in the reconnect code
  cifs: Add tracepoints for errors on flush or fsync
  cifs: log warning message (once) if out of disk space
  cifs: fail i/o on soft mounts if sessionsetup errors out
  smb3: fix problem with null cifs super block with previous patch
  SMB3: Backup intent flag missing from some more ops
2020-02-09 13:27:17 -08:00
Steve French
51d92d69f7 smb3: Add defines for new information level, FileIdInformation
See MS-FSCC 2.4.43.  Valid to be quried from most
Windows servers (among others).

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2020-02-06 17:32:24 -06:00
Steve French
ab3459d8f0 smb3: print warning once if posix context returned on open
SMB3.1.1 POSIX Context processing is not complete yet - so print warning
(once) if server returns it on open.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2020-02-06 17:31:56 -06:00
Steve French
2391ca41b4 smb3: add one more dynamic tracepoint missing from strict fsync path
We didn't have a dynamic trace point for catching errors in
file_write_and_wait_range error cases in cifs_strict_fsync.

Since not all apps check for write behind errors, it can be
important for debugging to be able to trace these error
paths.

Suggested-and-reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-02-06 17:21:23 -06:00
Aurelien Aptel
e3e056c351 cifs: fix mode bits from dir listing when mounted with modefromsid
When mounting with -o modefromsid, the mode bits are stored in an
ACE. Directory enumeration (e.g. ls -l /mnt) triggers an SMB Query Dir
which does not include ACEs in its response. The mode bits in this
case are silently set to a default value of 755 instead.

This patch marks the dentry created during the directory enumeration
as needing re-evaluation (i.e. additional Query Info with ACEs) so
that the mode bits can be properly extracted.

Quick repro:

$ mount.cifs //win19.test/data /mnt -o ...,modefromsid
$ touch /mnt/foo && chmod 751 /mnt/foo
$ stat /mnt/foo
  # reports 751 (OK)
$ sleep 2
  # dentry older than 1s by default get invalidated
$ ls -l /mnt
  # since dentry invalid, ls does a Query Dir
  # and reports foo as 755 (WRONG)

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-02-06 17:19:38 -06:00
Aurelien Aptel
cc95b67727 cifs: fix channel signing
The server var was accidentally used as an iterator over the global
list of connections, thus overwritten the passed argument. This
resulted in the wrong signing key being returned for extra channels.

Fix this by using a separate var to iterate.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-02-06 12:42:36 -06:00
Steve French
d26c2ddd33 cifs: add SMB3 change notification support
A commonly used SMB3 feature is change notification, allowing an
app to be notified about changes to a directory. The SMB3
Notify request blocks until the server detects a change to that
directory or its contents that matches the completion flags
that were passed in and the "watch_tree" flag (which indicates
whether subdirectories under this directory should be also
included).  See MS-SMB2 2.2.35 for additional detail.

To use this simply pass in the following structure to ioctl:

 struct __attribute__((__packed__)) smb3_notify {
        uint32_t completion_filter;
        bool    watch_tree;
 } __packed;

 using CIFS_IOC_NOTIFY  0x4005cf09
 or equivalently _IOW(CIFS_IOCTL_MAGIC, 9, struct smb3_notify)

SMB3 change notification is supported by all major servers.
The ioctl will block until the server detects a change to that
directory or its subdirectories (if watch_tree is set).

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
2020-02-06 09:14:28 -06:00
Aurelien Aptel
343a1b777a cifs: make multichannel warning more visible
When no interfaces are returned by the server we cannot open multiple
channels. Make it more obvious by reporting that to the user at the
VFS log level.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-02-06 09:12:16 -06:00
Ronnie Sahlberg
09c40b1535 cifs: fix soft mounts hanging in the reconnect code
RHBZ: 1795423

This is the SMB1 version of a patch we already have for SMB2

In recent DFS updates we have a new variable controlling how many times we will
retry to reconnect the share.
If DFS is not used, then this variable is initialized to 0 in:

static inline int
dfs_cache_get_nr_tgts(const struct dfs_cache_tgt_list *tl)
{
        return tl ? tl->tl_numtgts : 0;
}

This means that in the reconnect loop in smb2_reconnect() we will immediately wrap retries to -1
and never actually get to pass this conditional:

                if (--retries)
                        continue;

The effect is that we no longer reach the point where we fail the commands with -EHOSTDOWN
and basically the kernel threads are virtually hung and unkillable.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
2020-02-06 09:12:00 -06:00
Steve French
f2bf09e97b cifs: Add tracepoints for errors on flush or fsync
Makes it easier to debug errors on writeback that happen later,
and are being returned on flush or fsync

For example:
  writetest-17829 [002] .... 13583.407859: cifs_flush_err: ino=90 rc=-28

Signed-off-by: Steve French <stfrench@microsoft.com>
2020-02-05 18:24:19 -06:00
Steve French
d6fd41905e cifs: log warning message (once) if out of disk space
We ran into a confusing problem where an application wasn't checking
return code on close and so user didn't realize that the application
ran out of disk space.  log a warning message (once) in these
cases. For example:

  [ 8407.391909] Out of space writing to \\oleg-server\small-share

Signed-off-by: Steve French <stfrench@microsoft.com>
Reported-by: Oleg Kravtsov <oleg@tuxera.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-02-05 17:58:52 -06:00
Ronnie Sahlberg
b0dd940e58 cifs: fail i/o on soft mounts if sessionsetup errors out
RHBZ: 1579050

If we have a soft mount we should fail commands for session-setup
failures (such as the password having changed/ account being deleted/ ...)
and return an error back to the application.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
2020-02-05 06:32:41 -06:00
Steve French
87f93d82e0 smb3: fix problem with null cifs super block with previous patch
Add check for null cifs_sb to create_options helper

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2020-02-05 06:32:19 -06:00
Linus Torvalds
bddea11b1b Merge branch 'imm.timestamp' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs timestamp updates from Al Viro:
 "More 64bit timestamp work"

* 'imm.timestamp' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  kernfs: don't bother with timestamp truncation
  fs: Do not overload update_time
  fs: Delete timespec64_trunc()
  fs: ubifs: Eliminate timespec64_trunc() usage
  fs: ceph: Delete timespec64_trunc() usage
  fs: cifs: Delete usage of timespec64_trunc
  fs: fat: Eliminate timespec64_trunc() usage
  utimes: Clamp the timestamps in notify_change()
2020-02-05 05:02:42 +00:00
Alexey Dobriyan
97a32539b9 proc: convert everything to "struct proc_ops"
The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

	llseek		=> proc_lseek
	unlocked_ioctl	=> proc_ioctl

	xxx		=> proc_xxx

	delete ".owner = THIS_MODULE" line

[akpm@linux-foundation.org: fix drivers/isdn/capi/kcapi_proc.c]
[sfr@canb.auug.org.au: fix kernel/sched/psi.c]
  Link: http://lkml.kernel.org/r/20200122180545.36222f50@canb.auug.org.au
Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 03:05:26 +00:00
Amir Goldstein
0f060936e4 SMB3: Backup intent flag missing from some more ops
When "backup intent" is requested on the mount (e.g. backupuid or
backupgid mount options), the corresponding flag was missing from
some of the operations.

Change all operations to use the macro cifs_create_options() to
set the backup intent flag if needed.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-02-03 16:12:47 -06:00
Steve French
b581098482 cifs: update internal module version number
To 2.25

Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-31 15:13:22 -06:00
Ronnie Sahlberg
c54849ddd8 cifs: fix soft mounts hanging in the reconnect code
RHBZ: 1795429

In recent DFS updates we have a new variable controlling how many times we will
retry to reconnect the share.
If DFS is not used, then this variable is initialized to 0 in:

static inline int
dfs_cache_get_nr_tgts(const struct dfs_cache_tgt_list *tl)
{
        return tl ? tl->tl_numtgts : 0;
}

This means that in the reconnect loop in smb2_reconnect() we will immediately wrap retries to -1
and never actually get to pass this conditional:

                if (--retries)
                        continue;

The effect is that we no longer reach the point where we fail the commands with -EHOSTDOWN
and basically the kernel threads are virtually hung and unkillable.

Fixes: a3a53b7603 (cifs: Add support for failover in smb2_reconnect())
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
CC: Stable <stable@vger.kernel.org>
2020-01-30 15:23:55 -06:00
Vincent Whitchurch
f1f27ad745 CIFS: Fix task struct use-after-free on reconnect
The task which created the MID may be gone by the time cifsd attempts to
call the callbacks on MIDs from cifs_reconnect().

This leads to a use-after-free of the task struct in cifs_wake_up_task:

 ==================================================================
 BUG: KASAN: use-after-free in __lock_acquire+0x31a0/0x3270
 Read of size 8 at addr ffff8880103e3a68 by task cifsd/630

 CPU: 0 PID: 630 Comm: cifsd Not tainted 5.5.0-rc6+ #119
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
 Call Trace:
  dump_stack+0x8e/0xcb
  print_address_description.constprop.5+0x1d3/0x3c0
  ? __lock_acquire+0x31a0/0x3270
  __kasan_report+0x152/0x1aa
  ? __lock_acquire+0x31a0/0x3270
  ? __lock_acquire+0x31a0/0x3270
  kasan_report+0xe/0x20
  __lock_acquire+0x31a0/0x3270
  ? __wake_up_common+0x1dc/0x630
  ? _raw_spin_unlock_irqrestore+0x4c/0x60
  ? mark_held_locks+0xf0/0xf0
  ? _raw_spin_unlock_irqrestore+0x39/0x60
  ? __wake_up_common_lock+0xd5/0x130
  ? __wake_up_common+0x630/0x630
  lock_acquire+0x13f/0x330
  ? try_to_wake_up+0xa3/0x19e0
  _raw_spin_lock_irqsave+0x38/0x50
  ? try_to_wake_up+0xa3/0x19e0
  try_to_wake_up+0xa3/0x19e0
  ? cifs_compound_callback+0x178/0x210
  ? set_cpus_allowed_ptr+0x10/0x10
  cifs_reconnect+0xa1c/0x15d0
  ? generic_ip_connect+0x1860/0x1860
  ? rwlock_bug.part.0+0x90/0x90
  cifs_readv_from_socket+0x479/0x690
  cifs_read_from_socket+0x9d/0xe0
  ? cifs_readv_from_socket+0x690/0x690
  ? mempool_resize+0x690/0x690
  ? rwlock_bug.part.0+0x90/0x90
  ? memset+0x1f/0x40
  ? allocate_buffers+0xff/0x340
  cifs_demultiplex_thread+0x388/0x2a50
  ? cifs_handle_standard+0x610/0x610
  ? rcu_read_lock_held_common+0x120/0x120
  ? mark_lock+0x11b/0xc00
  ? __lock_acquire+0x14ed/0x3270
  ? __kthread_parkme+0x78/0x100
  ? lockdep_hardirqs_on+0x3e8/0x560
  ? lock_downgrade+0x6a0/0x6a0
  ? lockdep_hardirqs_on+0x3e8/0x560
  ? _raw_spin_unlock_irqrestore+0x39/0x60
  ? cifs_handle_standard+0x610/0x610
  kthread+0x2bb/0x3a0
  ? kthread_create_worker_on_cpu+0xc0/0xc0
  ret_from_fork+0x3a/0x50

 Allocated by task 649:
  save_stack+0x19/0x70
  __kasan_kmalloc.constprop.5+0xa6/0xf0
  kmem_cache_alloc+0x107/0x320
  copy_process+0x17bc/0x5370
  _do_fork+0x103/0xbf0
  __x64_sys_clone+0x168/0x1e0
  do_syscall_64+0x9b/0xec0
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

 Freed by task 0:
  save_stack+0x19/0x70
  __kasan_slab_free+0x11d/0x160
  kmem_cache_free+0xb5/0x3d0
  rcu_core+0x52f/0x1230
  __do_softirq+0x24d/0x962

 The buggy address belongs to the object at ffff8880103e32c0
  which belongs to the cache task_struct of size 6016
 The buggy address is located 1960 bytes inside of
  6016-byte region [ffff8880103e32c0, ffff8880103e4a40)
 The buggy address belongs to the page:
 page:ffffea000040f800 refcount:1 mapcount:0 mapping:ffff8880108da5c0
 index:0xffff8880103e4c00 compound_mapcount: 0
 raw: 4000000000010200 ffffea00001f2208 ffffea00001e3408 ffff8880108da5c0
 raw: ffff8880103e4c00 0000000000050003 00000001ffffffff 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  ffff8880103e3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8880103e3980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 >ffff8880103e3a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                           ^
  ffff8880103e3a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8880103e3b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ==================================================================

This can be reliably reproduced by adding the below delay to
cifs_reconnect(), running find(1) on the mount, restarting the samba
server while find is running, and killing find during the delay:

  	spin_unlock(&GlobalMid_Lock);
  	mutex_unlock(&server->srv_mutex);

 +	msleep(10000);
 +
  	cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
  	list_for_each_safe(tmp, tmp2, &retry_list) {
  		mid_entry = list_entry(tmp, struct mid_q_entry, qhead);

Fix this by holding a reference to the task struct until the MID is
freed.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-01-26 19:24:17 -06:00
Chen Zhou
050d2a8b69 cifs: use PTR_ERR_OR_ZERO() to simplify code
PTR_ERR_OR_ZERO contains if(IS_ERR(...)) + PTR_ERR, just use
PTR_ERR_OR_ZERO directly.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
2020-01-26 19:24:17 -06:00
Ronnie Sahlberg
8bd0d70144 cifs: add support for fallocate mode 0 for non-sparse files
RHBZ 1336264

When we extend a file we must also force the size to be updated.

This fixes an issue with holetest in xfs-tests which performs the following
sequence :
1, create a new file
2, use fallocate mode==0 to populate the file
3, mmap the file
4, touch each page by reading the mmapped region.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:17 -06:00
Ronnie Sahlberg
fe12926863 cifs: fix NULL dereference in match_prepath
RHBZ: 1760879

Fix an oops in match_prepath() by making sure that the prepath string is not
NULL before we pass it into strcmp().

This is similar to other checks we make for example in cifs_root_iget()

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:17 -06:00
Steve French
643fbceef4 smb3: fix default permissions on new files when mounting with modefromsid
When mounting with "modefromsid" mount parm most servers will require
that some default permissions are given to users in the ACL on newly
created files, files created with the new 'sd context' - when passing in
an sd context on create, permissions are not inherited from the parent
directory, so in addition to the ACE with the special SID which contains
the mode, we also must pass in an ACE allowing users to access the file
(GENERIC_ALL for authenticated users seemed like a reasonable default,
although later we could allow a mount option or config switch to make
it GENERIC_ALL for EVERYONE special sid).

CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-By: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-01-26 19:24:17 -06:00
Boris Protopopov
438471b679 CIFS: Add support for setting owner info, dos attributes, and create time
This is needed for backup/restore scenarios among others.

Add extended attribute "system.cifs_ntsd" (and alias "system.smb3_ntsd")
to allow for setting owner and DACL in the security descriptor. This is in
addition to the existing "system.cifs_acl" and "system.smb3_acl" attributes
that allow for setting DACL only. Add support for setting creation time and
dos attributes using set_file_info() calls to complement the existing
support for getting these attributes via query_path_info() calls.

Signed-off-by: Boris Protopopov <bprotopopov@hotmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:17 -06:00
YueHaibing
c4985c3d99 cifs: remove set but not used variable 'server'
fs/cifs/smb2pdu.c: In function 'SMB2_query_directory':
fs/cifs/smb2pdu.c:4444:26: warning:
 variable 'server' set but not used [-Wunused-but-set-variable]
  struct TCP_Server_Info *server;

It is not used, so remove it.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:17 -06:00
Paulo Alcantara (SUSE)
0a5a98863c cifs: Fix memory allocation in __smb2_handle_cancelled_cmd()
__smb2_handle_cancelled_cmd() is called under a spin lock held in
cifs_mid_q_entry_release(), so make its memory allocation GFP_ATOMIC.

This issue was observed when running xfstests generic/028:

[ 1722.589204] CIFS VFS: \\192.168.30.26 Cancelling wait for mid 72064 cmd: 5
[ 1722.590687] CIFS VFS: \\192.168.30.26 Cancelling wait for mid 72065 cmd: 17
[ 1722.593529] CIFS VFS: \\192.168.30.26 Cancelling wait for mid 72066 cmd: 6
[ 1723.039014] BUG: sleeping function called from invalid context at mm/slab.h:565
[ 1723.040710] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 30877, name: cifsd
[ 1723.045098] CPU: 3 PID: 30877 Comm: cifsd Not tainted 5.5.0-rc4+ #313
[ 1723.046256] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
[ 1723.048221] Call Trace:
[ 1723.048689]  dump_stack+0x97/0xe0
[ 1723.049268]  ___might_sleep.cold+0xd1/0xe1
[ 1723.050069]  kmem_cache_alloc_trace+0x204/0x2b0
[ 1723.051051]  __smb2_handle_cancelled_cmd+0x40/0x140 [cifs]
[ 1723.052137]  smb2_handle_cancelled_mid+0xf6/0x120 [cifs]
[ 1723.053247]  cifs_mid_q_entry_release+0x44d/0x630 [cifs]
[ 1723.054351]  ? cifs_reconnect+0x26a/0x1620 [cifs]
[ 1723.055325]  cifs_demultiplex_thread+0xad4/0x14a0 [cifs]
[ 1723.056458]  ? cifs_handle_standard+0x2c0/0x2c0 [cifs]
[ 1723.057365]  ? kvm_sched_clock_read+0x14/0x30
[ 1723.058197]  ? sched_clock+0x5/0x10
[ 1723.058838]  ? sched_clock_cpu+0x18/0x110
[ 1723.059629]  ? lockdep_hardirqs_on+0x17d/0x250
[ 1723.060456]  kthread+0x1ab/0x200
[ 1723.061149]  ? cifs_handle_standard+0x2c0/0x2c0 [cifs]
[ 1723.062078]  ? kthread_create_on_node+0xd0/0xd0
[ 1723.062897]  ret_from_fork+0x3a/0x50

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Fixes: 9150c3adbf ("CIFS: Close open handle after interrupted close")
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-01-26 19:24:17 -06:00
Paulo Alcantara (SUSE)
5739375ee4 cifs: Fix mount options set in automount
Starting from 4a367dc044, we must set the mount options based on the
DFS full path rather than the resolved target, that is, cifs_mount()
will be responsible for resolving the DFS link (cached) as well as
performing failover to any other targets in the referral.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reported-by: Martijn de Gouw <martijn.de.gouw@prodrive-technologies.com>
Fixes: 4a367dc044 ("cifs: Add support for failover in cifs_mount()")
Link: https://lore.kernel.org/linux-cifs/39643d7d-2abb-14d3-ced6-c394fab9a777@prodrive-technologies.com
Tested-by: Martijn de Gouw <martijn.de.gouw@prodrive-technologies.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Steve French
463a7b457c cifs: fix unitialized variable poential problem with network I/O cache lock patch
static analysis with Coverity detected an issue with the following
commit:

 Author: Paulo Alcantara (SUSE) <pc@cjr.nz>
 Date:   Wed Dec 4 17:38:03 2019 -0300

    cifs: Avoid doing network I/O while holding cache lock

Addresses-Coverity: ("Uninitialized pointer read")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
YueHaibing
eecfc57130 cifs: Fix return value in __update_cache_entry
copy_ref_data() may return error, it should be
returned to upstream caller.

Fixes: 03535b72873b ("cifs: Avoid doing network I/O while holding cache lock")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
742d8de018 cifs: Avoid doing network I/O while holding cache lock
When creating or updating a cache entry, we need to get an DFS
referral (get_dfs_referral), so avoid holding any locks during such
network operation.

To prevent that, do the following:
* change cache hashtable sync method from RCU sync to a read/write
  lock.
* use GFP_ATOMIC in memory allocations.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
06d57378bc cifs: Fix potential deadlock when updating vol in cifs_reconnect()
We can't acquire volume lock while refreshing the DFS cache because
cifs_reconnect() may call dfs_cache_update_vol() while we are walking
through the volume list.

To prevent that, make vol_info refcounted, create a temp list with all
volumes eligible for refreshing, and then use it without any locks
held.

Besides, replace vol_lock with a spinlock and protect cache_ttl from
concurrent accesses or changes.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
ff2f7fc082 cifs: Merge is_path_valid() into get_normalized_path()
Just do the trivial path validation in get_normalized_path().

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
345c1a4a9e cifs: Introduce helpers for finding TCP connection
Add helpers for finding TCP connections that are good candidates for
being used by DFS refresh worker.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
199c6bdfb0 cifs: Get rid of kstrdup_const()'d paths
The DFS cache API is mostly used with heap allocated strings.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
185352ae61 cifs: Clean up DFS referral cache
Do some renaming and code cleanup.

No functional changes.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
David Howells
6629400a22 cifs: Don't use iov_iter::type directly
Don't use iov_iter::type directly, but rather use the new accessor
functions that have been added.  This allows the .type field to be split
and rearranged without the need to update the filesystems.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Ronnie Sahlberg
731b82bb17 cifs: set correct max-buffer-size for smb2_ioctl_init()
Fix two places where we need to adjust down the max response size for
ioctl when it is used together with compounding.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org>
2020-01-26 19:24:16 -06:00
Ronnie Sahlberg
37478608f0 cifs: use compounding for open and first query-dir for readdir()
Combine the initial SMB2_Open and the first SMB2_Query_Directory in a compound.
This shaves one round-trip of each directory listing, changing it from 4 to 3
for small directories.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-01-26 19:24:16 -06:00
Ronnie Sahlberg
af08f9e79c cifs: create a helper function to parse the query-directory response buffer
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-01-26 19:24:16 -06:00
Ronnie Sahlberg
0a17799cc0 cifs: prepare SMB2_query_directory to be used with compounding
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2020-01-26 19:24:16 -06:00
zhengbin
01d1bd76a1 fs/cifs/cifssmb.c: use true,false for bool variable
Fixes coccicheck warning:

fs/cifs/cifssmb.c:4622:3-22: WARNING: Assignment of 0/1 to bool variable
fs/cifs/cifssmb.c:4756:3-22: WARNING: Assignment of 0/1 to bool variable

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
zhengbin
720aec0126 fs/cifs/smb2ops.c: use true,false for bool variable
Fixes coccicheck warning:

fs/cifs/smb2ops.c:807:2-36: WARNING: Assignment of 0/1 to bool variable

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
046aca3c25 cifs: Optimize readdir on reparse points
When listing a directory with thounsands of files and most of them are
reparse points, we simply marked all those dentries for revalidation
and then sending additional (compounded) create/getinfo/close requests
for each of them.

Instead, upon receiving a response from an SMB2_QUERY_DIRECTORY
(FileIdFullDirectoryInformation) command, the directory entries that
have a file attribute of FILE_ATTRIBUTE_REPARSE_POINT will contain an
EaSize field with a reparse tag in it, so we parse it and mark the
dentry for revalidation only if it is a DFS or a symlink.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-12-23 09:04:44 -06:00
Nathan Chancellor
7935799e04 cifs: Adjust indentation in smb2_open_file
Clang warns:

../fs/cifs/smb2file.c:70:3: warning: misleading indentation; statement
is not part of the previous 'if' [-Wmisleading-indentation]
         if (oparms->tcon->use_resilient) {
         ^
../fs/cifs/smb2file.c:66:2: note: previous statement is here
        if (rc)
        ^
1 warning generated.

This warning occurs because there is a space after the tab on this line.
Remove it so that the indentation is consistent with the Linux kernel
coding style and clang no longer warns.

Fixes: 592fafe644 ("Add resilienthandles mount parm")
Link: https://github.com/ClangBuiltLinux/linux/issues/826
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-12-23 09:04:44 -06:00
Pavel Shilovsky
d919131935 CIFS: Close cached root handle only if it has a lease
SMB2_tdis() checks if a root handle is valid in order to decide
whether it needs to close the handle or not. However if another
thread has reference for the handle, it may end up with putting
the reference twice. The extra reference that we want to put
during the tree disconnect is the reference that has a directory
lease. So, track the fact that we have a directory lease and
close the handle only in that case.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-12-13 00:49:57 -06:00
Steve French
e0fc5b1153 SMB3: Fix crash in SMB2_open_init due to uninitialized field in compounding path
Ran into an intermittent crash in
	SMB2_open_init+0x2f6/0x970
due to oparms.cifs_sb not being initialized when called from:
	smb2_compound_op+0x45d/0x1690
Zero the whole oparms struct in the compounding path before setting up the
oparms so we don't risk any uninitialized fields.

Fixes: fdef665ba4 ("smb3: fix mode passed in on create for modetosid mount option")

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-12-13 00:49:38 -06:00
Steve French
281393894a smb3: fix refcount underflow warning on unmount when no directory leases
Fix refcount underflow warning when unmounting to servers which didn't grant
directory leases.

[  301.680095] refcount_t: underflow; use-after-free.
[  301.680192] WARNING: CPU: 1 PID: 3569 at lib/refcount.c:28
refcount_warn_saturate+0xb4/0xf3
...
[  301.682139] Call Trace:
[  301.682240]  close_shroot+0x97/0xda [cifs]
[  301.682351]  SMB2_tdis+0x7c/0x176 [cifs]
[  301.682456]  ? _get_xid+0x58/0x91 [cifs]
[  301.682563]  cifs_put_tcon.part.0+0x99/0x202 [cifs]
[  301.682637]  ? ida_free+0x99/0x10a
[  301.682727]  ? cifs_umount+0x3d/0x9d [cifs]
[  301.682829]  cifs_put_tlink+0x3a/0x50 [cifs]
[  301.682929]  cifs_umount+0x44/0x9d [cifs]

Fixes: 72e73c78c4 ("cifs: close the shared root handle on tree disconnect")

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reported-and-tested-by: Arthur Marsh <arthur.marsh@internode.on.net>
2019-12-09 19:47:10 -06:00
Deepa Dinamani
918c900987 fs: cifs: Delete usage of timespec64_trunc
timestamp_truncate() is the replacement api for
timespec64_trunc. timestamp_truncate() additionally clamps
timestamps to make sure the timestamps lie within the
permitted range for the filesystem.

Truncate the timestamps in the struct cifs_attr at the
site of assignment to inode times. This
helps us use the right fs api timestamp_trucate() to
perform the truncation.

Also update the ktime_get_* api to match the one used in
current_time(). This allows for timestamps to be updated
the same way always.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: stfrench@microsoft.com
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-12-08 19:10:52 -05:00
Linus Torvalds
a78f7cdddb 9 cifs/smb3 fixes: two timestamp fixes, one oops fix (during oplock break) for stable, two fixes found in multichannel testing, two fixes for file create when using modeforsid mount parm
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Merge tag '5.5-rc-smb3-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "Nine cifs/smb3 fixes:

   - one fix for stable (oops during oplock break)

   - two timestamp fixes including important one for updating mtime at
     close to avoid stale metadata caching issue on dirty files (also
     improves perf by using SMB2_CLOSE_FLAG_POSTQUERY_ATTRIB over the
     wire)

   - two fixes for "modefromsid" mount option for file create (now
     allows mode bits to be set more atomically and accurately on create
     by adding "sd_context" on create when modefromsid specified on
     mount)

   - two fixes for multichannel found in testing this week against
     different servers

   - two small cleanup patches"

* tag '5.5-rc-smb3-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
  smb3: improve check for when we send the security descriptor context on create
  smb3: fix mode passed in on create for modetosid mount option
  cifs: fix possible uninitialized access and race on iface_list
  cifs: Fix lookup of SMB connections on multichannel
  smb3: query attributes on file close
  smb3: remove unused flag passed into close functions
  cifs: remove redundant assignment to pointer pneg_ctxt
  fs: cifs: Fix atime update check vs mtime
  CIFS: Fix NULL-pointer dereference in smb2_push_mandatory_locks
2019-12-08 12:12:18 -08:00
Steve French
231e2a0ba5 smb3: improve check for when we send the security descriptor context on create
We had cases in the previous patch where we were sending the security
descriptor context on SMB3 open (file create) in cases when we hadn't
mounted with with "modefromsid" mount option.

Add check for that mount flag before calling ad_sd_context in
open init.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-12-07 17:38:22 -06:00
Steve French
fdef665ba4 smb3: fix mode passed in on create for modetosid mount option
When using the special SID to store the mode bits in an ACE (See
http://technet.microsoft.com/en-us/library/hh509017(v=ws.10).aspx)
which is enabled with mount parm "modefromsid" we were not
passing in the mode via SMB3 create (although chmod was enabled).
SMB3 create allows a security descriptor context to be passed
in (which is more atomic and thus preferable to setting the mode
bits after create via a setinfo).

This patch enables setting the mode bits on create when using
modefromsid mount option.  In addition it fixes an endian
error in the definition of the Control field flags in the SMB3
security descriptor. It also makes the ACE type of the special
SID better match the documentation (and behavior of servers
which use this to store mode bits in SMB3 ACLs).

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-12-06 14:15:52 -06:00
Linus Torvalds
0aecba6173 Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs d_inode/d_flags memory ordering fixes from Al Viro:
 "Fallout from tree-wide audit for ->d_inode/->d_flags barriers use.
  Basically, the problem is that negative pinned dentries require
  careful treatment - unless ->d_lock is locked or parent is held at
  least shared, another thread can make them positive right under us.

  Most of the uses turned out to be safe - the main surprises as far as
  filesystems are concerned were

   - race in dget_parent() fastpath, that might end up with the caller
     observing the returned dentry _negative_, due to insufficient
     barriers. It is positive in memory, but we could end up seeing the
     wrong value of ->d_inode in CPU cache. Fixed.

   - manual checks that result of lookup_one_len_unlocked() is positive
     (and rejection of negatives). Again, insufficient barriers (we
     might end up with inconsistent observed values of ->d_inode and
     ->d_flags). Fixed by switching to a new primitive that does the
     checks itself and returns ERR_PTR(-ENOENT) instead of a negative
     dentry. That way we get rid of boilerplate converting negatives
     into ERR_PTR(-ENOENT) in the callers and have a single place to
     deal with the barrier-related mess - inside fs/namei.c rather than
     in every caller out there.

  The guts of pathname resolution *do* need to be careful - the race
  found by Ritesh is real, as well as several similar races.
  Fortunately, it turns out that we can take care of that with fairly
  local changes in there.

  The tree-wide audit had not been fun, and I hate the idea of repeating
  it. I think the right approach would be to annotate the places where
  we are _not_ guaranteed ->d_inode/->d_flags stability and have sparse
  catch regressions. But I'm still not sure what would be the least
  invasive way of doing that and it's clearly the next cycle fodder"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs/namei.c: fix missing barriers when checking positivity
  fix dget_parent() fastpath race
  new helper: lookup_positive_unlocked()
  fs/namei.c: pull positivity check into follow_managed()
2019-12-06 09:06:58 -08:00
Aurelien Aptel
9a7d5a9e6d cifs: fix possible uninitialized access and race on iface_list
iface[0] was accessed regardless of the count value and without
locking.

* check count before accessing any ifaces
* make copy of iface list (it's a simple POD array) and use it without
  locking.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
2019-12-04 11:51:18 -06:00
Paulo Alcantara (SUSE)
3345bb44ba cifs: Fix lookup of SMB connections on multichannel
With the addition of SMB session channels, we introduced new TCP
server pointers that have no sessions or tcons associated with them.

In this case, when we started looking for TCP connections, we might
end up picking session channel rather than the master connection,
hence failing to get either a session or a tcon.

In order to fix that, this patch introduces a new "is_channel" field
to TCP_Server_Info structure so we can skip session channels during
lookup of connections.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-12-04 11:50:32 -06:00
Steve French
43f8a6a74e smb3: query attributes on file close
Since timestamps on files on most servers can be updated at
close, and since timestamps on our dentries default to one
second we can have stale timestamps in some common cases
(e.g. open, write, close, stat, wait one second, stat - will
show different mtime for the first and second stat).

The SMB2/SMB3 protocol allows querying timestamps at close
so add the code to request timestamp and attr information
(which is cheap for the server to provide) to be returned
when a file is closed (it is not needed for the many
paths that call SMB2_close that are from compounded
query infos and close nor is it needed for some of
the cases where a directory close immediately follows a
directory open.

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-12-03 15:48:02 -06:00
Steve French
9e8fae2597 smb3: remove unused flag passed into close functions
close was relayered to allow passing in an async flag which
is no longer needed in this path.  Remove the unneeded parameter
"flags" passed in on close.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2019-12-02 18:07:17 -06:00
Colin Ian King
a9f76cf827 cifs: remove redundant assignment to pointer pneg_ctxt
The pointer pneg_ctxt is being initialized with a value that is never
read and it is being updated later with a new value.  The assignment
is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-12-02 16:55:08 -06:00
Deepa Dinamani
69738cfdfa fs: cifs: Fix atime update check vs mtime
According to the comment in the code and commit log, some apps
expect atime >= mtime; but the introduced code results in
atime==mtime.  Fix the comparison to guard against atime<mtime.

Fixes: 9b9c5bea0b ("cifs: do not return atime less than mtime")
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: stfrench@microsoft.com
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-12-02 15:15:35 -06:00
Pavel Shilovsky
6f582b273e CIFS: Fix NULL-pointer dereference in smb2_push_mandatory_locks
Currently when the client creates a cifsFileInfo structure for
a newly opened file, it allocates a list of byte-range locks
with a pointer to the new cfile and attaches this list to the
inode's lock list. The latter happens before initializing all
other fields, e.g. cfile->tlink. Thus a partially initialized
cifsFileInfo structure becomes available to other threads that
walk through the inode's lock list. One example of such a thread
may be an oplock break worker thread that tries to push all
cached byte-range locks. This causes NULL-pointer dereference
in smb2_push_mandatory_locks() when accessing cfile->tlink:

[598428.945633] BUG: kernel NULL pointer dereference, address: 0000000000000038
...
[598428.945749] Workqueue: cifsoplockd cifs_oplock_break [cifs]
[598428.945793] RIP: 0010:smb2_push_mandatory_locks+0xd6/0x5a0 [cifs]
...
[598428.945834] Call Trace:
[598428.945870]  ? cifs_revalidate_mapping+0x45/0x90 [cifs]
[598428.945901]  cifs_oplock_break+0x13d/0x450 [cifs]
[598428.945909]  process_one_work+0x1db/0x380
[598428.945914]  worker_thread+0x4d/0x400
[598428.945921]  kthread+0x104/0x140
[598428.945925]  ? process_one_work+0x380/0x380
[598428.945931]  ? kthread_park+0x80/0x80
[598428.945937]  ret_from_fork+0x35/0x40

Fix this by reordering initialization steps of the cifsFileInfo
structure: initialize all the fields first and then add the new
byte-range lock list to the inode's lock list.

Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-12-02 15:15:00 -06:00
Linus Torvalds
937d6eefc7 Here's the main documentation changes for 5.5:
- Various kerneldoc script enhancements.
 
  - More RST conversions; those are slowing down as we run out of things to
    convert, but we're a ways from done still.
 
  - Dan's "maintainer profile entry" work landed at last.  Now we just need
    to get maintainers to fill in the profiles...
 
  - A reworking of the parallel build setup to work better with a variety of
    systems (and to not take over huge systems entirely in particular).
 
  - The MAINTAINERS file is now converted to RST during the build.
    Hopefully nobody ever tries to print this thing, or they will need to
    load a lot of paper.
 
  - A script and documentation making it easy for maintainers to add Link:
    tags at commit time.
 
 Also included is the removal of a bunch of spurious CR characters.
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Merge tag 'docs-5.5a' of git://git.lwn.net/linux

Pull Documentation updates from Jonathan Corbet:
 "Here are the main documentation changes for 5.5:

   - Various kerneldoc script enhancements.

   - More RST conversions; those are slowing down as we run out of
     things to convert, but we're a ways from done still.

   - Dan's "maintainer profile entry" work landed at last. Now we just
     need to get maintainers to fill in the profiles...

   - A reworking of the parallel build setup to work better with a
     variety of systems (and to not take over huge systems entirely in
     particular).

   - The MAINTAINERS file is now converted to RST during the build.
     Hopefully nobody ever tries to print this thing, or they will need
     to load a lot of paper.

   - A script and documentation making it easy for maintainers to add
     Link: tags at commit time.

  Also included is the removal of a bunch of spurious CR characters"

* tag 'docs-5.5a' of git://git.lwn.net/linux: (91 commits)
  docs: remove a bunch of stray CRs
  docs: fix up the maintainer profile document
  libnvdimm, MAINTAINERS: Maintainer Entry Profile
  Maintainer Handbook: Maintainer Entry Profile
  MAINTAINERS: Reclaim the P: tag for Maintainer Entry Profile
  docs, parallelism: Rearrange how jobserver reservations are made
  docs, parallelism: Do not leak blocking mode to other readers
  docs, parallelism: Fix failure path and add comment
  Documentation: Remove bootmem_debug from kernel-parameters.txt
  Documentation: security: core.rst: fix warnings
  Documentation/process/howto/kokr: Update for 4.x -> 5.x versioning
  Documentation/translation: Use Korean for Korean translation title
  docs/memory-barriers.txt: Remove remaining references to mmiowb()
  docs/memory-barriers.txt/kokr: Update I/O section to be clearer about CPU vs thread
  docs/memory-barriers.txt/kokr: Fix style, spacing and grammar in I/O section
  Documentation/kokr: Kill all references to mmiowb()
  docs/memory-barriers.txt/kokr: Rewrite "KERNEL I/O BARRIER EFFECTS" section
  docs: Add initial documentation for devfreq
  Documentation: Document how to get links with git am
  docs: Add request_irq() documentation
  ...
2019-12-02 11:51:02 -08:00
Dan Carpenter via samba-technical
68464b88cc CIFS: fix a white space issue in cifs_get_inode_info()
We accidentally messed up the indenting on this if statement.

Fixes: 16c696a6c300 ("CIFS: refactor cifs_get_inode_info()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-27 11:31:49 -06:00
Steve French
1656a07a89 cifs: update internal module version number
To 2.24

Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 10:00:02 -06:00
Paulo Alcantara (SUSE)
ff6b6f3f91 cifs: Always update signing key of first channel
Update signing key of first channel whenever generating the master
sigining/encryption/decryption keys rather than only in cifs_mount().

This also fixes reconnect when re-establishing smb sessions to other
servers.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 09:59:28 -06:00
Paulo Alcantara (SUSE)
5bb30a4dd6 cifs: Fix retrieval of DFS referrals in cifs_mount()
Make sure that DFS referrals are sent to newly resolved root targets
as in a multi tier DFS setup.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Link: https://lkml.kernel.org/r/05aa2995-e85e-0ff4-d003-5bb08bd17a22@canonical.com
Cc: stable@vger.kernel.org
Tested-by: Matthew Ruffell <matthew.ruffell@canonical.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 09:36:49 -06:00
Paulo Alcantara (SUSE)
84a1f5b1cc cifs: Fix potential softlockups while refreshing DFS cache
We used to skip reconnects on all SMB2_IOCTL commands due to SMB3+
FSCTL_VALIDATE_NEGOTIATE_INFO - which made sense since we're still
establishing a SMB session.

However, when refresh_cache_worker() calls smb2_get_dfs_refer() and
we're under reconnect, SMB2_ioctl() will not be able to get a proper
status error (e.g. -EHOSTDOWN in case we failed to reconnect) but an
-EAGAIN from cifs_send_recv() thus looping forever in
refresh_cache_worker().

Fixes: e99c63e4d8 ("SMB3: Fix deadlock in validate negotiate hits reconnect")
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Suggested-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 09:33:04 -06:00
Paulo Alcantara (SUSE)
df3df923b3 cifs: Fix lookup of root ses in DFS referral cache
We don't care about module aliasing validation in
cifs_compose_mount_options(..., is_smb3) when finding the root SMB
session of an DFS namespace in order to refresh DFS referral cache.

The following issue has been observed when mounting with '-t smb3' and
then specifying 'vers=2.0':

...
Nov 08 15:27:08 tw kernel: address conversion returned 0 for FS0.WIN.LOCAL
Nov 08 15:27:08 tw kernel: [kworke] ==> dns_query((null),FS0.WIN.LOCAL,13,(null))
Nov 08 15:27:08 tw kernel: [kworke] call request_key(,FS0.WIN.LOCAL,)
Nov 08 15:27:08 tw kernel: [kworke] ==> dns_resolver_cmp(FS0.WIN.LOCAL,FS0.WIN.LOCAL)
Nov 08 15:27:08 tw kernel: [kworke] <== dns_resolver_cmp() = 1
Nov 08 15:27:08 tw kernel: [kworke] <== dns_query() = 13
Nov 08 15:27:08 tw kernel: fs/cifs/dns_resolve.c: dns_resolve_server_name_to_ip: resolved: FS0.WIN.LOCAL to 192.168.30.26
===> Nov 08 15:27:08 tw kernel: CIFS VFS: vers=2.0 not permitted when mounting with smb3
Nov 08 15:27:08 tw kernel: fs/cifs/dfs_cache.c: CIFS VFS: leaving refresh_tcon (xid = 26) rc = -22
...

Fixes: 5072010ccf ("cifs: Fix DFS cache refresher for DFS links")
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 09:25:32 -06:00
Paulo Alcantara (SUSE)
8354d88efd cifs: Fix use-after-free bug in cifs_reconnect()
Ensure we grab an active reference in cifs superblock while doing
failover to prevent automounts (DFS links) of expiring and then
destroying the superblock pointer.

This patch fixes the following KASAN report:

[  464.301462] BUG: KASAN: use-after-free in
cifs_reconnect+0x6ab/0x1350
[  464.303052] Read of size 8 at addr ffff888155e580d0 by task
cifsd/1107

[  464.304682] CPU: 3 PID: 1107 Comm: cifsd Not tainted 5.4.0-rc4+ #13
[  464.305552] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
BIOS rel-1.12.1-0-ga5cab58-rebuilt.opensuse.org 04/01/2014
[  464.307146] Call Trace:
[  464.307875]  dump_stack+0x5b/0x90
[  464.308631]  print_address_description.constprop.0+0x16/0x200
[  464.309478]  ? cifs_reconnect+0x6ab/0x1350
[  464.310253]  ? cifs_reconnect+0x6ab/0x1350
[  464.311040]  __kasan_report.cold+0x1a/0x41
[  464.311811]  ? cifs_reconnect+0x6ab/0x1350
[  464.312563]  kasan_report+0xe/0x20
[  464.313300]  cifs_reconnect+0x6ab/0x1350
[  464.314062]  ? extract_hostname.part.0+0x90/0x90
[  464.314829]  ? printk+0xad/0xde
[  464.315525]  ? _raw_spin_lock+0x7c/0xd0
[  464.316252]  ? _raw_read_lock_irq+0x40/0x40
[  464.316961]  ? ___ratelimit+0xed/0x182
[  464.317655]  cifs_readv_from_socket+0x289/0x3b0
[  464.318386]  cifs_read_from_socket+0x98/0xd0
[  464.319078]  ? cifs_readv_from_socket+0x3b0/0x3b0
[  464.319782]  ? try_to_wake_up+0x43c/0xa90
[  464.320463]  ? cifs_small_buf_get+0x4b/0x60
[  464.321173]  ? allocate_buffers+0x98/0x1a0
[  464.321856]  cifs_demultiplex_thread+0x218/0x14a0
[  464.322558]  ? cifs_handle_standard+0x270/0x270
[  464.323237]  ? __switch_to_asm+0x40/0x70
[  464.323893]  ? __switch_to_asm+0x34/0x70
[  464.324554]  ? __switch_to_asm+0x40/0x70
[  464.325226]  ? __switch_to_asm+0x40/0x70
[  464.325863]  ? __switch_to_asm+0x34/0x70
[  464.326505]  ? __switch_to_asm+0x40/0x70
[  464.327161]  ? __switch_to_asm+0x34/0x70
[  464.327784]  ? finish_task_switch+0xa1/0x330
[  464.328414]  ? __switch_to+0x363/0x640
[  464.329044]  ? __schedule+0x575/0xaf0
[  464.329655]  ? _raw_spin_lock_irqsave+0x82/0xe0
[  464.330301]  kthread+0x1a3/0x1f0
[  464.330884]  ? cifs_handle_standard+0x270/0x270
[  464.331624]  ? kthread_create_on_node+0xd0/0xd0
[  464.332347]  ret_from_fork+0x35/0x40

[  464.333577] Allocated by task 1110:
[  464.334381]  save_stack+0x1b/0x80
[  464.335123]  __kasan_kmalloc.constprop.0+0xc2/0xd0
[  464.335848]  cifs_smb3_do_mount+0xd4/0xb00
[  464.336619]  legacy_get_tree+0x6b/0xa0
[  464.337235]  vfs_get_tree+0x41/0x110
[  464.337975]  fc_mount+0xa/0x40
[  464.338557]  vfs_kern_mount.part.0+0x6c/0x80
[  464.339227]  cifs_dfs_d_automount+0x336/0xd29
[  464.339846]  follow_managed+0x1b1/0x450
[  464.340449]  lookup_fast+0x231/0x4a0
[  464.341039]  path_openat+0x240/0x1fd0
[  464.341634]  do_filp_open+0x126/0x1c0
[  464.342277]  do_sys_open+0x1eb/0x2c0
[  464.342957]  do_syscall_64+0x5e/0x190
[  464.343555]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[  464.344772] Freed by task 0:
[  464.345347]  save_stack+0x1b/0x80
[  464.345966]  __kasan_slab_free+0x12c/0x170
[  464.346576]  kfree+0xa6/0x270
[  464.347211]  rcu_core+0x39c/0xc80
[  464.347800]  __do_softirq+0x10d/0x3da

[  464.348919] The buggy address belongs to the object at
ffff888155e58000
                which belongs to the cache kmalloc-256 of size 256
[  464.350222] The buggy address is located 208 bytes inside of
                256-byte region [ffff888155e58000, ffff888155e58100)
[  464.351575] The buggy address belongs to the page:
[  464.352333] page:ffffea0005579600 refcount:1 mapcount:0
mapping:ffff88815a803400 index:0x0 compound_mapcount: 0
[  464.353583] flags: 0x200000000010200(slab|head)
[  464.354209] raw: 0200000000010200 ffffea0005576200 0000000400000004
ffff88815a803400
[  464.355353] raw: 0000000000000000 0000000080100010 00000001ffffffff
0000000000000000
[  464.356458] page dumped because: kasan: bad access detected

[  464.367005] Memory state around the buggy address:
[  464.367787]  ffff888155e57f80: fc fc fc fc fc fc fc fc fc fc fc fc
fc fc fc fc
[  464.368877]  ffff888155e58000: fb fb fb fb fb fb fb fb fb fb fb fb
fb fb fb fb
[  464.369967] >ffff888155e58080: fb fb fb fb fb fb fb fb fb fb fb fb
fb fb fb fb
[  464.371111]                                                  ^
[  464.371775]  ffff888155e58100: fc fc fc fc fc fc fc fc fc fc fc fc
fc fc fc fc
[  464.372893]  ffff888155e58180: fc fc fc fc fc fc fc fc fc fc fc fc
fc fc fc fc
[  464.373983] ==================================================================

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 09:23:10 -06:00
Aurelien Aptel
85150929a1 cifs: dump channel info in DebugData
* show server&TCP states for extra channels
* mention if an interface has a channel connected to it

In this version three of the patch, fixed minor printk format
issue pointed out by the kbuild robot.
Reported-by: kbuild test robot <lkp@intel.com>

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:17:12 -06:00
Steve French
1ae9a5a551 smb3: dump in_send and num_waiters stats counters by default
Number of requests in_send and the number of waiters on sendRecv
are useful counters in various cases, move them from
CONFIG_CIFS_STATS2 to be on by default especially with multichannel

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
2019-11-25 01:17:12 -06:00
Aurelien Aptel
65a37a3414 cifs: try harder to open new channels
Previously we would only loop over the iface list once.
This patch tries to loop over multiple times until all channels are
opened. It will also try to reuse RSS ifaces.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:17:12 -06:00
Pavel Shilovsky
9bd4540836 CIFS: Properly process SMB3 lease breaks
Currenly we doesn't assume that a server may break a lease
from RWH to RW which causes us setting a wrong lease state
on a file and thus mistakenly flushing data and byte-range
locks and purging cached data on the client. This leads to
performance degradation because subsequent IOs go directly
to the server.

Fix this by propagating new lease state and epoch values
to the oplock break handler through cifsFileInfo structure
and removing the use of cifsInodeInfo flags for that. It
allows to avoid some races of several lease/oplock breaks
using those flags in parallel.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:17:12 -06:00
Ronnie Sahlberg
32546a9586 cifs: move cifsFileInfo_put logic into a work-queue
This patch moves the final part of the cifsFileInfo_put() logic where we
need a write lock on lock_sem to be processed in a separate thread that
holds no other locks.
This is to prevent deadlocks like the one below:

> there are 6 processes looping to while trying to down_write
> cinode->lock_sem, 5 of them from _cifsFileInfo_put, and one from
> cifs_new_fileinfo
>
> and there are 5 other processes which are blocked, several of them
> waiting on either PG_writeback or PG_locked (which are both set), all
> for the same page of the file
>
> 2 inode_lock() (inode->i_rwsem) for the file
> 1 wait_on_page_writeback() for the page
> 1 down_read(inode->i_rwsem) for the inode of the directory
> 1 inode_lock()(inode->i_rwsem) for the inode of the directory
> 1 __lock_page
>
>
> so processes are blocked waiting on:
>   page flags PG_locked and PG_writeback for one specific page
>   inode->i_rwsem for the directory
>   inode->i_rwsem for the file
>   cifsInodeInflock_sem
>
>
>
> here are the more gory details (let me know if I need to provide
> anything more/better):
>
> [0 00:48:22.765] [UN]  PID: 8863   TASK: ffff8c691547c5c0  CPU: 3
> COMMAND: "reopen_file"
>  #0 [ffff9965007e3ba8] __schedule at ffffffff9b6e6095
>  #1 [ffff9965007e3c38] schedule at ffffffff9b6e64df
>  #2 [ffff9965007e3c48] rwsem_down_write_slowpath at ffffffff9af283d7
>  #3 [ffff9965007e3cb8] legitimize_path at ffffffff9b0f975d
>  #4 [ffff9965007e3d08] path_openat at ffffffff9b0fe55d
>  #5 [ffff9965007e3dd8] do_filp_open at ffffffff9b100a33
>  #6 [ffff9965007e3ee0] do_sys_open at ffffffff9b0eb2d6
>  #7 [ffff9965007e3f38] do_syscall_64 at ffffffff9ae04315
> * (I think legitimize_path is bogus)
>
> in path_openat
>         } else {
>                 const char *s = path_init(nd, flags);
>                 while (!(error = link_path_walk(s, nd)) &&
>                         (error = do_last(nd, file, op)) > 0) {  <<<<
>
> do_last:
>         if (open_flag & O_CREAT)
>                 inode_lock(dir->d_inode);  <<<<
>         else
> so it's trying to take inode->i_rwsem for the directory
>
>      DENTRY           INODE           SUPERBLK     TYPE PATH
> ffff8c68bb8e79c0 ffff8c691158ef20 ffff8c6915bf9000 DIR  /mnt/vm1_smb/
> inode.i_rwsem is ffff8c691158efc0
>
> <struct rw_semaphore 0xffff8c691158efc0>:
>         owner: <struct task_struct 0xffff8c6914275d00> (UN -   8856 -
> reopen_file), counter: 0x0000000000000003
>         waitlist: 2
>         0xffff9965007e3c90     8863   reopen_file      UN 0  1:29:22.926
>   RWSEM_WAITING_FOR_WRITE
>         0xffff996500393e00     9802   ls               UN 0  1:17:26.700
>   RWSEM_WAITING_FOR_READ
>
>
> the owner of the inode.i_rwsem of the directory is:
>
> [0 00:00:00.109] [UN]  PID: 8856   TASK: ffff8c6914275d00  CPU: 3
> COMMAND: "reopen_file"
>  #0 [ffff99650065b828] __schedule at ffffffff9b6e6095
>  #1 [ffff99650065b8b8] schedule at ffffffff9b6e64df
>  #2 [ffff99650065b8c8] schedule_timeout at ffffffff9b6e9f89
>  #3 [ffff99650065b940] msleep at ffffffff9af573a9
>  #4 [ffff99650065b948] _cifsFileInfo_put.cold.63 at ffffffffc0a42dd6 [cifs]
>  #5 [ffff99650065ba38] cifs_writepage_locked at ffffffffc0a0b8f3 [cifs]
>  #6 [ffff99650065bab0] cifs_launder_page at ffffffffc0a0bb72 [cifs]
>  #7 [ffff99650065bb30] invalidate_inode_pages2_range at ffffffff9b04d4bd
>  #8 [ffff99650065bcb8] cifs_invalidate_mapping at ffffffffc0a11339 [cifs]
>  #9 [ffff99650065bcd0] cifs_revalidate_mapping at ffffffffc0a1139a [cifs]
> #10 [ffff99650065bcf0] cifs_d_revalidate at ffffffffc0a014f6 [cifs]
> #11 [ffff99650065bd08] path_openat at ffffffff9b0fe7f7
> #12 [ffff99650065bdd8] do_filp_open at ffffffff9b100a33
> #13 [ffff99650065bee0] do_sys_open at ffffffff9b0eb2d6
> #14 [ffff99650065bf38] do_syscall_64 at ffffffff9ae04315
>
> cifs_launder_page is for page 0xffffd1e2c07d2480
>
> crash> page.index,mapping,flags 0xffffd1e2c07d2480
>       index = 0x8
>       mapping = 0xffff8c68f3cd0db0
>   flags = 0xfffffc0008095
>
>   PAGE-FLAG       BIT  VALUE
>   PG_locked         0  0000001
>   PG_uptodate       2  0000004
>   PG_lru            4  0000010
>   PG_waiters        7  0000080
>   PG_writeback     15  0008000
>
>
> inode is ffff8c68f3cd0c40
> inode.i_rwsem is ffff8c68f3cd0ce0
>      DENTRY           INODE           SUPERBLK     TYPE PATH
> ffff8c68a1f1b480 ffff8c68f3cd0c40 ffff8c6915bf9000 REG
> /mnt/vm1_smb/testfile.8853
>
>
> this process holds the inode->i_rwsem for the parent directory, is
> laundering a page attached to the inode of the file it's opening, and in
> _cifsFileInfo_put is trying to down_write the cifsInodeInflock_sem
> for the file itself.
>
>
> <struct rw_semaphore 0xffff8c68f3cd0ce0>:
>         owner: <struct task_struct 0xffff8c6914272e80> (UN -   8854 -
> reopen_file), counter: 0x0000000000000003
>         waitlist: 1
>         0xffff9965005dfd80     8855   reopen_file      UN 0  1:29:22.912
>   RWSEM_WAITING_FOR_WRITE
>
> this is the inode.i_rwsem for the file
>
> the owner:
>
> [0 00:48:22.739] [UN]  PID: 8854   TASK: ffff8c6914272e80  CPU: 2
> COMMAND: "reopen_file"
>  #0 [ffff99650054fb38] __schedule at ffffffff9b6e6095
>  #1 [ffff99650054fbc8] schedule at ffffffff9b6e64df
>  #2 [ffff99650054fbd8] io_schedule at ffffffff9b6e68e2
>  #3 [ffff99650054fbe8] __lock_page at ffffffff9b03c56f
>  #4 [ffff99650054fc80] pagecache_get_page at ffffffff9b03dcdf
>  #5 [ffff99650054fcc0] grab_cache_page_write_begin at ffffffff9b03ef4c
>  #6 [ffff99650054fcd0] cifs_write_begin at ffffffffc0a064ec [cifs]
>  #7 [ffff99650054fd30] generic_perform_write at ffffffff9b03bba4
>  #8 [ffff99650054fda8] __generic_file_write_iter at ffffffff9b04060a
>  #9 [ffff99650054fdf0] cifs_strict_writev.cold.70 at ffffffffc0a4469b [cifs]
> #10 [ffff99650054fe48] new_sync_write at ffffffff9b0ec1dd
> #11 [ffff99650054fed0] vfs_write at ffffffff9b0eed35
> #12 [ffff99650054ff00] ksys_write at ffffffff9b0eefd9
> #13 [ffff99650054ff38] do_syscall_64 at ffffffff9ae04315
>
> the process holds the inode->i_rwsem for the file to which it's writing,
> and is trying to __lock_page for the same page as in the other processes
>
>
> the other tasks:
> [0 00:00:00.028] [UN]  PID: 8859   TASK: ffff8c6915479740  CPU: 2
> COMMAND: "reopen_file"
>  #0 [ffff9965007b39d8] __schedule at ffffffff9b6e6095
>  #1 [ffff9965007b3a68] schedule at ffffffff9b6e64df
>  #2 [ffff9965007b3a78] schedule_timeout at ffffffff9b6e9f89
>  #3 [ffff9965007b3af0] msleep at ffffffff9af573a9
>  #4 [ffff9965007b3af8] cifs_new_fileinfo.cold.61 at ffffffffc0a42a07 [cifs]
>  #5 [ffff9965007b3b78] cifs_open at ffffffffc0a0709d [cifs]
>  #6 [ffff9965007b3cd8] do_dentry_open at ffffffff9b0e9b7a
>  #7 [ffff9965007b3d08] path_openat at ffffffff9b0fe34f
>  #8 [ffff9965007b3dd8] do_filp_open at ffffffff9b100a33
>  #9 [ffff9965007b3ee0] do_sys_open at ffffffff9b0eb2d6
> #10 [ffff9965007b3f38] do_syscall_64 at ffffffff9ae04315
>
> this is opening the file, and is trying to down_write cinode->lock_sem
>
>
> [0 00:00:00.041] [UN]  PID: 8860   TASK: ffff8c691547ae80  CPU: 2
> COMMAND: "reopen_file"
> [0 00:00:00.057] [UN]  PID: 8861   TASK: ffff8c6915478000  CPU: 3
> COMMAND: "reopen_file"
> [0 00:00:00.059] [UN]  PID: 8858   TASK: ffff8c6914271740  CPU: 2
> COMMAND: "reopen_file"
> [0 00:00:00.109] [UN]  PID: 8862   TASK: ffff8c691547dd00  CPU: 6
> COMMAND: "reopen_file"
>  #0 [ffff9965007c3c78] __schedule at ffffffff9b6e6095
>  #1 [ffff9965007c3d08] schedule at ffffffff9b6e64df
>  #2 [ffff9965007c3d18] schedule_timeout at ffffffff9b6e9f89
>  #3 [ffff9965007c3d90] msleep at ffffffff9af573a9
>  #4 [ffff9965007c3d98] _cifsFileInfo_put.cold.63 at ffffffffc0a42dd6 [cifs]
>  #5 [ffff9965007c3e88] cifs_close at ffffffffc0a07aaf [cifs]
>  #6 [ffff9965007c3ea0] __fput at ffffffff9b0efa6e
>  #7 [ffff9965007c3ee8] task_work_run at ffffffff9aef1614
>  #8 [ffff9965007c3f20] exit_to_usermode_loop at ffffffff9ae03d6f
>  #9 [ffff9965007c3f38] do_syscall_64 at ffffffff9ae0444c
>
> closing the file, and trying to down_write cifsi->lock_sem
>
>
> [0 00:48:22.839] [UN]  PID: 8857   TASK: ffff8c6914270000  CPU: 7
> COMMAND: "reopen_file"
>  #0 [ffff9965006a7cc8] __schedule at ffffffff9b6e6095
>  #1 [ffff9965006a7d58] schedule at ffffffff9b6e64df
>  #2 [ffff9965006a7d68] io_schedule at ffffffff9b6e68e2
>  #3 [ffff9965006a7d78] wait_on_page_bit at ffffffff9b03cac6
>  #4 [ffff9965006a7e10] __filemap_fdatawait_range at ffffffff9b03b028
>  #5 [ffff9965006a7ed8] filemap_write_and_wait at ffffffff9b040165
>  #6 [ffff9965006a7ef0] cifs_flush at ffffffffc0a0c2fa [cifs]
>  #7 [ffff9965006a7f10] filp_close at ffffffff9b0e93f1
>  #8 [ffff9965006a7f30] __x64_sys_close at ffffffff9b0e9a0e
>  #9 [ffff9965006a7f38] do_syscall_64 at ffffffff9ae04315
>
> in __filemap_fdatawait_range
>                         wait_on_page_writeback(page);
> for the same page of the file
>
>
>
> [0 00:48:22.718] [UN]  PID: 8855   TASK: ffff8c69142745c0  CPU: 7
> COMMAND: "reopen_file"
>  #0 [ffff9965005dfc98] __schedule at ffffffff9b6e6095
>  #1 [ffff9965005dfd28] schedule at ffffffff9b6e64df
>  #2 [ffff9965005dfd38] rwsem_down_write_slowpath at ffffffff9af283d7
>  #3 [ffff9965005dfdf0] cifs_strict_writev at ffffffffc0a0c40a [cifs]
>  #4 [ffff9965005dfe48] new_sync_write at ffffffff9b0ec1dd
>  #5 [ffff9965005dfed0] vfs_write at ffffffff9b0eed35
>  #6 [ffff9965005dff00] ksys_write at ffffffff9b0eefd9
>  #7 [ffff9965005dff38] do_syscall_64 at ffffffff9ae04315
>
>         inode_lock(inode);
>
>
> and one 'ls' later on, to see whether the rest of the mount is available
> (the test file is in the root, so we get blocked up on the directory
> ->i_rwsem), so the entire mount is unavailable
>
> [0 00:36:26.473] [UN]  PID: 9802   TASK: ffff8c691436ae80  CPU: 4
> COMMAND: "ls"
>  #0 [ffff996500393d28] __schedule at ffffffff9b6e6095
>  #1 [ffff996500393db8] schedule at ffffffff9b6e64df
>  #2 [ffff996500393dc8] rwsem_down_read_slowpath at ffffffff9b6e9421
>  #3 [ffff996500393e78] down_read_killable at ffffffff9b6e95e2
>  #4 [ffff996500393e88] iterate_dir at ffffffff9b103c56
>  #5 [ffff996500393ec8] ksys_getdents64 at ffffffff9b104b0c
>  #6 [ffff996500393f30] __x64_sys_getdents64 at ffffffff9b104bb6
>  #7 [ffff996500393f38] do_syscall_64 at ffffffff9ae04315
>
> in iterate_dir:
>         if (shared)
>                 res = down_read_killable(&inode->i_rwsem);  <<<<
>         else
>                 res = down_write_killable(&inode->i_rwsem);
>

Reported-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:17:12 -06:00
Aurelien Aptel
d70e9fa558 cifs: try opening channels after mounting
After doing mount() successfully we call cifs_try_adding_channels()
which will open as many channels as it can.

Channels are closed when the master session is closed.

The master connection becomes the first channel.

,-------------> global cifs_tcp_ses_list <-------------------------.
|                                                                  |
'- TCP_Server_Info  <-->  TCP_Server_Info  <-->  TCP_Server_Info <-'
      (master con)           (chan#1 con)         (chan#2 con)
      |      ^                    ^                    ^
      v      '--------------------|--------------------'
   cifs_ses                       |
   - chan_count = 3               |
   - chans[] ---------------------'
   - smb3signingkey[]
      (master signing key)

Note how channel connections don't have sessions. That's because
cifs_ses can only be part of one linked list (list_head are internal
to the elements).

For signing keys, each channel has its own signing key which must be
used only after the channel has been bound. While it's binding it must
use the master session signing key.

For encryption keys, since channel connections do not have sessions
attached we must now find matching session by looping over all sessions
in smb2_get_enc_key().

Each channel is opened like a regular server connection but at the
session setup request step it must set the
SMB2_SESSION_REQ_FLAG_BINDING flag and use the session id to bind to.

Finally, while sending in compound_send_recv() for requests that
aren't negprot, ses-setup or binding related, use a channel by cycling
through the available ones (round-robin).

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:16:30 -06:00
Aurelien Aptel
b8f7442bc4 CIFS: refactor cifs_get_inode_info()
Make logic of cifs_get_inode() much clearer by moving code to sub
functions and adding comments.

Document the steps this function does.

cifs_get_inode_info() gets and updates a file inode metadata from its
file path.

* If caller already has raw info data from server they can pass it.
* If inode already exists (just need to update) caller can pass it.

Step 1: get raw data from server if none was passed
Step 2: parse raw data into intermediate internal cifs_fattr struct
Step 3: set fattr uniqueid which is later used for inode number. This
        can sometime be done from raw data
Step 4: tweak fattr according to mount options (file_mode, acl to mode
        bits, uid, gid, etc)
Step 5: update or create inode from final fattr struct

* add is_smb1_server() helper
* add is_inode_cache_good() helper
* move SMB1-backupcreds-getinfo-retry to separate func
  cifs_backup_query_path_info().
* move set-uniqueid code to separate func cifs_set_fattr_ino()
* don't clobber uniqueid from backup cred retry
* fix some probable corner cases memleaks

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:16:30 -06:00
Aurelien Aptel
f6a6bf7c4d cifs: switch servers depending on binding state
Currently a lot of the code to initialize a connection & session uses
the cifs_ses as input. But depending on if we are opening a new session
or a new channel we need to use different server pointers.

Add a "binding" flag in cifs_ses and a helper function that returns
the server ptr a session should use (only in the sess establishment
code path).

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:16:30 -06:00
Aurelien Aptel
f780bd3fef cifs: add server param
As we get down to the transport layer, plenty of functions are passed
the session pointer and assume the transport to use is ses->server.

Instead we modify those functions to pass (ses, server) so that we
can decouple the session from the server.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:16:30 -06:00
Aurelien Aptel
bcc8880115 cifs: add multichannel mount options and data structs
adds:
- [no]multichannel to enable/disable multichannel
- max_channels=N to control how many channels to create

these options are then stored in the volume struct.

- store channels and max_channels in cifs_ses

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:16:30 -06:00
Aurelien Aptel
35adffed07 cifs: sort interface list by speed
New channels are going to be opened by walking the list sequentially,
so by sorting it we will connect to the fastest interfaces first.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:16:30 -06:00
Pavel Shilovsky
fa9c236249 CIFS: Fix SMB2 oplock break processing
Even when mounting modern protocol version the server may be
configured without supporting SMB2.1 leases and the client
uses SMB2 oplock to optimize IO performance through local caching.

However there is a problem in oplock break handling that leads
to missing a break notification on the client who has a file
opened. It latter causes big latencies to other clients that
are trying to open the same file.

The problem reproduces when there are multiple shares from the
same server mounted on the client. The processing code tries to
match persistent and volatile file ids from the break notification
with an open file but it skips all share besides the first one.
Fix this by looking up in all shares belonging to the server that
issued the oplock break.

Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:16:30 -06:00
Ronnie Sahlberg
3591bb83ee cifs: don't use 'pre:' for MODULE_SOFTDEP
It can cause
to fail with
modprobe: FATAL: Module <module> is builtin.

RHBZ: 1767094

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:16:30 -06:00
Long Li
4357d45f50 cifs: smbd: Return -EAGAIN when transport is reconnecting
During reconnecting, the transport may have already been destroyed and is in
the process being reconnected. In this case, return -EAGAIN to not fail and
to retry this I/O.

Signed-off-by: Long Li <longli@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:16:30 -06:00
Long Li
c21ce58eab cifs: smbd: Only queue work for error recovery on memory registration
It's not necessary to queue invalidated memory registration to work queue, as
all we need to do is to unmap the SG and make it usable again. This can save
CPU cycles in normal data paths as memory registration errors are rare and
normally only happens during reconnection.

Signed-off-by: Long Li <longli@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:16:30 -06:00
Ronnie Sahlberg
87bc2376ff smb3: add debug messages for closing unmatched open
Helps distinguish between an interrupted close and a truly
unmatched open.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:14:53 -06:00
Pavel Shilovsky
7b71843fa7 CIFS: Do not miss cancelled OPEN responses
When an OPEN command is cancelled we mark a mid as
cancelled and let the demultiplex thread process it
by closing an open handle. The problem is there is
a race between a system call thread and the demultiplex
thread and there may be a situation when the mid has
been already processed before it is set as cancelled.

Fix this by processing cancelled requests when mids
are being destroyed which means that there is only
one thread referencing a particular mid. Also set
mids as cancelled unconditionally on their state.

Cc: Stable <stable@vger.kernel.org>
Tested-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:14:53 -06:00
Pavel Shilovsky
86a7964be7 CIFS: Fix NULL pointer dereference in mid callback
There is a race between a system call processing thread
and the demultiplex thread when mid->resp_buf becomes NULL
and later is being accessed to get credits. It happens when
the 1st thread wakes up before a mid callback is called in
the 2nd one but the mid state has already been set to
MID_RESPONSE_RECEIVED. This causes NULL pointer dereference
in mid callback.

Fix this by saving credits from the response before we
update the mid state and then use this value in the mid
callback rather then accessing a response buffer.

Cc: Stable <stable@vger.kernel.org>
Fixes: ee258d7915 ("CIFS: Move credit processing to mid callbacks for SMB3")
Tested-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:14:53 -06:00