linux-stable.git/fs/cifs, branch linux-3.19.y

cifs: fix use-after-free bug in find_writable_file

2015-04-19T08:10:23+00:00

commit e1e9bda22d7ddf88515e8fe401887e313922823e upstream.

Under intermittent network outages, find_writable_file() is susceptible
to the following race condition, which results in a user-after-free in
the cifs_writepages code-path:

Thread 1                                        Thread 2
========                                        ========

inv_file = NULL
refind = 0
spin_lock(&cifs_file_list_lock)

// invalidHandle found on openFileList

inv_file = open_file
// inv_file->count currently 1

cifsFileInfo_get(inv_file)
// inv_file->count = 2

spin_unlock(&cifs_file_list_lock);

cifs_reopen_file()                            cifs_close()
// fails (rc != 0)                            ->cifsFileInfo_put()
                                       spin_lock(&cifs_file_list_lock)
                                       // inv_file->count = 1
                                       spin_unlock(&cifs_file_list_lock)

spin_lock(&cifs_file_list_lock);
list_move_tail(&inv_file->flist,
      &cifs_inode->openFileList);
spin_unlock(&cifs_file_list_lock);

cifsFileInfo_put(inv_file);
->spin_lock(&cifs_file_list_lock)

  // inv_file->count = 0
  list_del(&cifs_file->flist);
  // cleanup!!
  kfree(cifs_file);

  spin_unlock(&cifs_file_list_lock);

spin_lock(&cifs_file_list_lock);
++refind;
// refind = 1
goto refind_writable;

At this point we loop back through with an invalid inv_file pointer
and a refind value of 1. On second pass, inv_file is not overwritten on
openFileList traversal, and is subsequently dereferenced.

Signed-off-by: David Disseldorp 
Reviewed-by: Jeff Layton 
Signed-off-by: Steve French 
Signed-off-by: Greg Kroah-Hartman

cifs: smb2_clone_range() - exit on unhandled error

2015-04-19T08:10:22+00:00

commit 2477bc58d49edb1c0baf59df7dc093dce682af2b upstream.

While attempting to clone a file on a samba server, we receive a
STATUS_INVALID_DEVICE_REQUEST. This is mapped to -EOPNOTSUPP which
isn't handled in smb2_clone_range(). We end up looping in the while loop
making same call to the samba server over and over again.

The proposed fix is to exit and return the error value when encountered
with an unhandled error.

Signed-off-by: Sachin Prabhu 
Signed-off-by: Steve French 
Signed-off-by: Steve French 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6

2015-02-04T18:22:08+00:00

Pull cifs fixes from Steve French:
 "Three small cifs fixes.  One fixes a hang under stress, and the other
  two are security related"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix MUST SecurityFlags filtering
  Complete oplock break jobs before closing file handle
  cifs: use memzero_explicit to clear stack buffer

cifs: fix MUST SecurityFlags filtering

2015-01-27T01:38:26+00:00

If CONFIG_CIFS_WEAK_PW_HASH is not set, CIFSSEC_MUST_LANMAN
and CIFSSEC_MUST_PLNTXT is defined as 0.

When setting new SecurityFlags without any MUST flags,
your flags would be overwritten with CIFSSEC_MUST_LANMAN (0).

Signed-off-by: Niklas Cassel 
Signed-off-by: Steve French

Complete oplock break jobs before closing file handle

2015-01-20T02:20:46+00:00

Commit
c11f1df5003d534fd067f0168bfad7befffb3b5c
requires writers to wait for any pending oplock break handler to
complete before proceeding to write. This is done by waiting on bit
CIFS_INODE_PENDING_OPLOCK_BREAK in cifsFileInfo->flags. This bit is
cleared by the oplock break handler job queued on the workqueue once it
has completed handling the oplock break allowing writers to proceed with
writing to the file.

While testing, it was noticed that the filehandle could be closed while
there is a pending oplock break which results in the oplock break
handler on the cifsiod workqueue being cancelled before it has had a
chance to execute and clear the CIFS_INODE_PENDING_OPLOCK_BREAK bit.
Any subsequent attempt to write to this file hangs waiting for the
CIFS_INODE_PENDING_OPLOCK_BREAK bit to be cleared.

We fix this by ensuring that we also clear the bit
CIFS_INODE_PENDING_OPLOCK_BREAK when we remove the oplock break handler
from the workqueue.

The bug was found by Red Hat QA while testing using ltp's fsstress
command.

Signed-off-by: Sachin Prabhu 
Acked-by: Shirish Pargaonkar 
Signed-off-by: Jeff Layton 
Cc: stable@vger.kernel.org
Signed-off-by: Steve French

cifs: use memzero_explicit to clear stack buffer

2015-01-19T21:32:13+00:00

When leaving a function use memzero_explicit instead of memset(0) to
clear stack allocated buffers. memset(0) may be optimized away.

This particular buffer is highly likely to contain sensitive data which
we shouldn't leak (it's named 'passwd' after all).

Signed-off-by: Giel van Schijndel 
Acked-by: Herbert Xu 
Reported-at: http://www.viva64.com/en/b/0299/
Reported-by: Andrey Karpov
Reported-by: Svyatoslav Razmyslov
Signed-off-by: Steve French

fix deadlock in cifs_ioctl_clone()

2015-01-19T04:49:26+00:00

It really needs to check that src is non-directory *and* use
{un,}lock_two_nodirectories().  As it is, it's trivial to cause
double-lock (ioctl(fd, CIFS_IOC_COPYCHUNK_FILE, fd)) and if the
last argument is an fd of directory, we are asking for trouble
by violating the locking order - all directories go before all
non-directories.  If the last argument is an fd of parent
directory, it has 50% odds of locking child before parent,
which will cause AB-BA deadlock if we race with unlink().

Cc: stable@vger.kernel.org @ 3.13+
Signed-off-by: Al Viro

cifs: make new inode cache when file type is different

2014-12-22T20:16:21+00:00

In spite of different file type,
 if file is same name and same inode number, old inode cache is used.
This causes that you can not cd directory, can not cat SymbolicLink.
So this patch is that if file type is different, return error.

Reproducible sample :
1. create file 'a' at cifs client.
2. repeat rm and mkdir 'a' 4 times at server, then direcotry 'a' having same inode number is created.
   (Repeat 4 times, then same inode number is recycled.)
   (When server is under RHEL 6.6, 1 time is O.K.  Always same inode number is recycled.)
3. ls -li at client, then you can not cd directory, can not remove directory.

SymbolicLink has same problem.

Bug link:
https://bugzilla.kernel.org/show_bug.cgi?id=90011

Signed-off-by: Nakajima Akira 
Acked-by: Jeff Layton 
Signed-off-by: Steve French

Fix signed/unsigned pointer warning

2014-12-14T20:55:57+00:00

Commit 2ae83bf93882d1 ("[CIFS] Fix setting time before epoch (negative
time values)") changed "u64 t" to "s64 t", which makes do_div() complain
about a pointer signedness mismatch:

      CC      fs/cifs/netmisc.o
    In file included from ./arch/mips/include/asm/div64.h:12:0,
                     from include/linux/kernel.h:124,
                     from include/linux/list.h:8,
                     from include/linux/wait.h:6,
                     from include/linux/net.h:23,
                     from fs/cifs/netmisc.c:25:
    fs/cifs/netmisc.c: In function ‘cifs_NTtimeToUnix’:
    include/asm-generic/div64.h:43:28: warning: comparison of distinct pointer types lacks a cast [enabled by default]
      (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
                                ^
    fs/cifs/netmisc.c:941:22: note: in expansion of macro ‘do_div’
       ts.tv_nsec = (long)do_div(t, 10000000) * 100;

Introduce a temporary "u64 abs_t" variable to fix this.

Signed-off-by: Kevin Cernekee 
Signed-off-by: Steve French

Convert MessageID in smb2_hdr to LE

2014-12-14T20:55:45+00:00

We have encountered failures when When testing smb2 mounts on ppc64
machines when using both Samba as well as Windows 2012.

On poking around, the problem was determined to be caused by the
high endian MessageID passed in the header for smb2. On checking the
corresponding MID for smb1 is converted to LE before being sent on the
wire.

We have tested this patch successfully on a ppc64 machine.

Signed-off-by: Sachin Prabhu