[PATCH 0/4] FS-Cache: Miscellaneous fixes

[PATCH 0/4] FS-Cache: Miscellaneous fixes

[David Howells]

Attached are another couple of miscellaneous fixes for FS-Cache and
CacheFiles:

 (1) Fix a race between object burial in cachefiles and external rmdir.

 (2) Fix a race from a split atomic op.

 (3) Fix incomplete initialisation of cookie key space.

 (4) Fix out-of-bounds read.

The patches are tagged here:

	git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
	fscache-fixes-20181017

and can also be found on the following branch:

	http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=fscache-fixes

David
---
Al Viro (1):
      cachefiles: fix the race between cachefiles_bury_object() and rmdir(2)

David Howells (1):
      fscache: Fix incomplete initialisation of inline key space

Eric Sandeen (1):
      fscache: Fix out of bound read in long cookie keys

kiran.modukuri (1):
      fscache: Fix race in fscache_op_complete() due to split atomic_sub & read


 fs/cachefiles/namei.c         |    2 +-
 fs/fscache/cookie.c           |   31 ++++++++++---------------------
 fs/fscache/internal.h         |    1 -
 fs/fscache/main.c             |    4 +---
 include/linux/fscache-cache.h |    4 ++--
 5 files changed, 14 insertions(+), 28 deletions(-)

[PATCH 0/4] FS-Cache: Miscellaneous fixes

[David Howells]

Attached are another couple of miscellaneous fixes for FS-Cache and
CacheFiles:

 (1) Fix a race between object burial in cachefiles and external rmdir.

 (2) Fix a race from a split atomic op.

 (3) Fix incomplete initialisation of cookie key space.

 (4) Fix out-of-bounds read.

The patches are tagged here:

	git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
	fscache-fixes-20181017

and can also be found on the following branch:

	http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=fscache-fixes

David
---
Al Viro (1):
      cachefiles: fix the race between cachefiles_bury_object() and rmdir(2)

David Howells (1):
      fscache: Fix incomplete initialisation of inline key space

Eric Sandeen (1):
      fscache: Fix out of bound read in long cookie keys

kiran.modukuri (1):
      fscache: Fix race in fscache_op_complete() due to split atomic_sub & read


 fs/cachefiles/namei.c         |    2 +-
 fs/fscache/cookie.c           |   31 ++++++++++---------------------
 fs/fscache/internal.h         |    1 -
 fs/fscache/main.c             |    4 +---
 include/linux/fscache-cache.h |    4 ++--
 5 files changed, 14 insertions(+), 28 deletions(-)

[PATCH 1/4] cachefiles: fix the race between cachefiles_bury_object() and rmdir(2)

[David Howells]

From: Al Viro <viro@zeniv.linux.org.uk>

the victim might've been rmdir'ed just before the lock_rename();
unlike the normal callers, we do not look the source up after the
parents are locked - we know it beforehand and just recheck that it's
still the child of what used to be its parent.  Unfortunately,
the check is too weak - we don't spot a dead directory since its
->d_parent is unchanged, dentry is positive, etc.  So we sail all
the way to ->rename(), with hosting filesystems _not_ expecting
to be asked renaming an rmdir'ed subdirectory.

The fix is easy, fortunately - the lock on parent is sufficient for
making IS_DEADDIR() on child safe.

Cc: stable@vger.kernel.org
Fixes: 9ae326a69004 (CacheFiles: A cache that backs onto a mounted filesystem)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/cachefiles/namei.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index af2b17b21b94..95983c744164 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -343,7 +343,7 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache,
 	trap = lock_rename(cache->graveyard, dir);
 
 	/* do some checks before getting the grave dentry */
-	if (rep->d_parent != dir) {
+	if (rep->d_parent != dir || IS_DEADDIR(d_inode(rep))) {
 		/* the entry was probably culled when we dropped the parent dir
 		 * lock */
 		unlock_rename(cache->graveyard, dir);

Re: [PATCH 0/4] FS-Cache: Miscellaneous fixes

[Greg KH]

On Wed, Oct 17, 2018 at 03:23:14PM +0100, David Howells wrote:
> 
> Attached are another couple of miscellaneous fixes for FS-Cache and
> CacheFiles:
> 
>  (1) Fix a race between object burial in cachefiles and external rmdir.
> 
>  (2) Fix a race from a split atomic op.
> 
>  (3) Fix incomplete initialisation of cookie key space.
> 
>  (4) Fix out-of-bounds read.

Patches 1, 3, and 4 are now merged, thanks.  I didn't pull from you as
patch 2 needed to be dropped according to the thread.

thanks,

greg k-h