linux-stable.git/fs, branch v3.10.76

dcache: Fix locking bugs in backported "deal with deadlock in d_walk()"

2015-04-29T08:34:02+00:00

commit 20defcec264ceab2630356fb9d397f3d237b5e6d upstream in 3.2-stable

Steven Rostedt reported:
> Porting -rt to the latest 3.2 stable tree I triggered this bug:
>
> =====================================
> [ BUG: bad unlock balance detected! ]
> -------------------------------------
> rm/1638 is trying to release lock (rcu_read_lock) at:
> [] rcu_read_unlock+0x0/0x23
> but there are no more locks to release!
>
> other info that might help us debug this:
> 2 locks held by rm/1638:
>  #0:  (&sb->s_type->i_mutex_key#9/1){+.+.+.}, at: [] do_rmdir+0x5f/0xd2
>  #1:  (&sb->s_type->i_mutex_key#9){+.+.+.}, at: [] vfs_rmdir+0x49/0xac
>
> stack backtrace:
> Pid: 1638, comm: rm Not tainted 3.2.66-test-rt96+ #2
> Call Trace:
>  [] ? printk+0x1d/0x1f
>  [] print_unlock_inbalance_bug+0xc3/0xcd
>  [] lock_release_non_nested+0x98/0x1ec
>  [] ? trace_hardirqs_off_caller+0x18/0x90
>  [] ? local_clock+0x2d/0x50
>  [] ? d_hash+0x2f/0x2f
>  [] ? d_hash+0x2f/0x2f
>  [] lock_release+0x192/0x1ad
>  [] rcu_read_unlock+0x17/0x23
>  [] shrink_dcache_parent+0x227/0x270
>  [] vfs_rmdir+0x68/0xac
>  [] do_rmdir+0x98/0xd2
>  [] ? fput+0x1a3/0x1ab
>  [] ? sysenter_exit+0xf/0x1a
>  [] ? trace_hardirqs_on_caller+0x118/0x149
>  [] sys_unlinkat+0x2b/0x35
>  [] sysenter_do_call+0x12/0x12
>
>
>
>
> There's a path to calling rcu_read_unlock() without calling
> rcu_read_lock() in have_submounts().
>
> 	goto positive;
>
> positive:
> 	if (!locked && read_seqretry(&rename_lock, seq))
> 		goto rename_retry;
>
> rename_retry:
> 	rcu_read_unlock();
>
> in the above path, rcu_read_lock() is never done before calling
> rcu_read_unlock();

I reviewed locking contexts in all three functions that I changed when
backporting "deal with deadlock in d_walk()".  It's actually worse
than this:

- We don't hold this_parent->d_lock at the 'positive' label in
  have_submounts(), but it is unlocked after 'rename_retry'.
- There is an rcu_read_unlock() after the 'out' label in
  select_parent(), but it's not held at the 'goto out'.

Fix all three lock imbalances.

Reported-by: Steven Rostedt 
Signed-off-by: Ben Hutchings 
Tested-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

deal with deadlock in d_walk()

2015-04-29T08:34:00+00:00

commit ca5358ef75fc69fee5322a38a340f5739d997c10 upstream.

... by not hitting rename_retry for reasons other than rename having
happened.  In other words, do _not_ restart when finding that
between unlocking the child and locking the parent the former got
into __dentry_kill().  Skip the killed siblings instead...

Signed-off-by: Al Viro 
Cc: Ben Hutchings 
[hujianyang: Backported to 3.10 refer to the work of Ben Hutchings in 3.2:
 - As we only have try_to_ascend() and not d_walk(), apply this
   change to all callers of try_to_ascend()
 - Adjust context to make __dentry_kill() apply to d_kill()]
Signed-off-by: hujianyang 
Signed-off-by: Greg Kroah-Hartman

move d_rcu from overlapping d_child to overlapping d_alias

2015-04-29T08:34:00+00:00

commit 946e51f2bf37f1656916eb75bd0742ba33983c28 upstream.

Signed-off-by: Al Viro 
Cc: Ben Hutchings 
[hujianyang: Backported to 3.10 refer to the work of Ben Hutchings in 3.2:
 - Apply name changes in all the different places we use d_alias and d_child
 - Move the WARN_ON() in __d_free() to d_free() as we don't have dentry_free()]
Signed-off-by: hujianyang 
Signed-off-by: Greg Kroah-Hartman

splice: Apply generic position and size checks to each write

2015-04-29T08:33:57+00:00

commit 894c6350eaad7e613ae267504014a456e00a3e2a from the 3.2-stable branch.

We need to check the position and size of file writes against various
limits, using generic_write_check().  This was not being done for
the splice write path.  It was fixed upstream by commit 8d0207652cbe
("->splice_write() via ->write_iter()") but we can't apply that.

CVE-2014-7822

Signed-off-by: Ben Hutchings 
[Ben fixed it in 3.2 stable, i ported it to 3.10 stable]
Signed-off-by: Zhang Zhen 
Signed-off-by: Greg Kroah-Hartman

jfs: fix readdir regression

2015-04-29T08:33:57+00:00

Upstream commit 44512449, "jfs: fix readdir cookie incompatibility
with NFSv4", was backported incorrectly into the stable trees which
used the filldir callback (rather than dir_emit). The position is
being incorrectly passed to filldir for the . and .. entries.

The still-maintained stable trees that need to be fixed are 3.2.y,
3.4.y and 3.10.y.

https://bugzilla.kernel.org/show_bug.cgi?id=94741

Signed-off-by: Dave Kleikamp 
Cc: jfs-discussion@lists.sourceforge.net
Signed-off-by: Greg Kroah-Hartman

remove extra definitions of U32_MAX

2015-04-29T08:33:54+00:00

commit 04f9b74e4d96d349de12fdd4e6626af4a9f75e09 upstream.

Now that the definition is centralized in , the
definitions of U32_MAX (and related) elsewhere in the kernel can be
removed.

Signed-off-by: Alex Elder 
Acked-by: Sage Weil 
Acked-by: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

conditionally define U32_MAX

2015-04-29T08:33:54+00:00

commit 77719536dc00f8fd8f5abe6dadbde5331c37f996 upstream.

The symbol U32_MAX is defined in several spots.  Change these
definitions to be conditional.  This is in preparation for the next
patch, which centralizes the definition in .

Signed-off-by: Alex Elder 
Cc: Sage Weil 
Cc: David Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

pagemap: do not leak physical addresses to non-privileged userspace

2015-04-19T08:10:51+00:00

commit ab676b7d6fbf4b294bf198fb27ade5b0e865c7ce upstream.

As pointed by recent post[1] on exploiting DRAM physical imperfection,
/proc/PID/pagemap exposes sensitive information which can be used to do
attacks.

This disallows anybody without CAP_SYS_ADMIN to read the pagemap.

[1] http://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html

[ Eventually we might want to do anything more finegrained, but for now
  this is the simple model.   - Linus ]

Signed-off-by: Kirill A. Shutemov 
Acked-by: Konstantin Khlebnikov 
Acked-by: Andy Lutomirski 
Cc: Pavel Emelyanov 
Cc: Andrew Morton 
Cc: Mark Seaborn 
Signed-off-by: Linus Torvalds 
Signed-off-by: mancha security 
Signed-off-by: Greg Kroah-Hartman

ocfs2: _really_ sync the right range

2015-04-19T08:10:50+00:00

commit 64b4e2526d1cf6e6a4db6213d6e2b6e6ab59479a upstream.

"ocfs2 syncs the wrong range" had been broken; prior to it the
code was doing the wrong thing in case of O_APPEND, all right,
but _after_ it we were syncing the wrong range in 100% cases.
*ppos, aka iocb->ki_pos is incremented prior to that point,
so we are always doing sync on the area _after_ the one we'd
written to.

Spotted by Joseph Qi  back in January;
unfortunately, I'd missed his mail back then ;-/

Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

cifs: fix use-after-free bug in find_writable_file

2015-04-19T08:10:50+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