[PATCH 0/4 v2] Fix possible use after free with AIO

[PATCH 0/4 v2] Fix possible use after free with AIO

[Jan Kara]

  Hi,

  since nobody seem to have picked up any of the patches (at least
nobody told me so), I've added acks I received to the patches and I'm
sending them to Al for merging. Al, can you please merge these? Thanks.

								Honza

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[PATCH 1/4] ext4: Fix possible use-after-free with AIO

[Jan Kara]

Running AIO is pinning inode in memory using file reference. Once AIO
is completed using aio_complete(), file reference is put and inode can
be freed from memory. So we have to be sure that calling aio_complete()
is the last thing we do with the inode.

CC: linux-ext4@vger.kernel.org
CC: "Theodore Ts'o" <tytso@mit.edu>
CC: stable@vger.kernel.org
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c   |    2 +-
 fs/ext4/page-io.c |    9 ++++-----
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index cbfe13b..ba06638 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2977,9 +2977,9 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
 	if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
 		ext4_free_io_end(io_end);
 out:
+		inode_dio_done(inode);
 		if (is_async)
 			aio_complete(iocb, ret, 0);
-		inode_dio_done(inode);
 		return;
 	}
 
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 0016fbc..b42d04f 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -103,14 +103,13 @@ static int ext4_end_io(ext4_io_end_t *io)
 			 "(inode %lu, offset %llu, size %zd, error %d)",
 			 inode->i_ino, offset, size, ret);
 	}
-	if (io->iocb)
-		aio_complete(io->iocb, io->result, 0);
-
-	if (io->flag & EXT4_IO_END_DIRECT)
-		inode_dio_done(inode);
 	/* Wake up anyone waiting on unwritten extent conversion */
 	if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))
 		wake_up_all(ext4_ioend_wq(inode));
+	if (io->flag & EXT4_IO_END_DIRECT)
+		inode_dio_done(inode);
+	if (io->iocb)
+		aio_complete(io->iocb, io->result, 0);
 	return ret;
 }
 
-- 
1.7.1

Re: [PATCH 1/4] ext4: Fix possible use-after-free with AIO

[Theodore Ts'o]

On Wed, Jan 30, 2013 at 12:27:58AM +0100, Jan Kara wrote:
> Running AIO is pinning inode in memory using file reference. Once AIO
> is completed using aio_complete(), file reference is put and inode can
> be freed from memory. So we have to be sure that calling aio_complete()
> is the last thing we do with the inode.
> 
> CC: linux-ext4@vger.kernel.org
> CC: "Theodore Ts'o" <tytso@mit.edu>
> CC: stable@vger.kernel.org
> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
> Acked-by: Jeff Moyer <jmoyer@redhat.com>
> Signed-off-by: Jan Kara <jack@suse.cz>

I've picked up the ext4 change.  Sorry for not getting to this sooner.

     	       	   		       	   - Ted

[PATCH 2/4] xfs: Fix possible use-after-free with AIO

[Jan Kara]

Running AIO is pinning inode in memory using file reference. Once AIO
is completed using aio_complete(), file reference is put and inode can
be freed from memory. So we have to be sure that calling aio_complete()
is the last thing we do with the inode.

CC: xfs@oss.sgi.com
CC: Ben Myers <bpm@sgi.com>
CC: stable@vger.kernel.org
Reviewed-by: Ben Myers <bpm@sgi.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/xfs/xfs_aops.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 4111a40..5f707e5 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -86,11 +86,11 @@ xfs_destroy_ioend(
 	}
 
 	if (ioend->io_iocb) {
+		inode_dio_done(ioend->io_inode);
 		if (ioend->io_isasync) {
 			aio_complete(ioend->io_iocb, ioend->io_error ?
 					ioend->io_error : ioend->io_result, 0);
 		}
-		inode_dio_done(ioend->io_inode);
 	}
 
 	mempool_free(ioend, xfs_ioend_pool);
-- 
1.7.1

Re: [PATCH 2/4] xfs: Fix possible use-after-free with AIO

[Ben Myers]

Hi Jan,

On Wed, Jan 30, 2013 at 12:27:59AM +0100, Jan Kara wrote:
> Running AIO is pinning inode in memory using file reference. Once AIO
> is completed using aio_complete(), file reference is put and inode can
> be freed from memory. So we have to be sure that calling aio_complete()
> is the last thing we do with the inode.
> 
> CC: xfs@oss.sgi.com
> CC: Ben Myers <bpm@sgi.com>
> CC: stable@vger.kernel.org
> Reviewed-by: Ben Myers <bpm@sgi.com>
> Acked-by: Jeff Moyer <jmoyer@redhat.com>
> Signed-off-by: Jan Kara <jack@suse.cz>

We picked this up in the xfs tree.  Sorry to keep you hanging.

Regards,
	Ben

[PATCH 3/4] ocfs2: Fix possible use-after-free with AIO

[Jan Kara]

Running AIO is pinning inode in memory using file reference. Once AIO
is completed using aio_complete(), file reference is put and inode can
be freed from memory. So we have to be sure that calling aio_complete()
is the last thing we do with the inode.

CC: Joel Becker <jlbec@evilplan.org>
CC: ocfs2-devel@oss.oracle.com
CC: stable@vger.kernel.org
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ocfs2/aops.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 6577432..340bd02 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -593,9 +593,9 @@ static void ocfs2_dio_end_io(struct kiocb *iocb,
 	level = ocfs2_iocb_rw_locked_level(iocb);
 	ocfs2_rw_unlock(inode, level);
 
+	inode_dio_done(inode);
 	if (is_async)
 		aio_complete(iocb, ret, 0);
-	inode_dio_done(inode);
 }
 
 /*
-- 
1.7.1

[PATCH 4/4] fs: Fix possible use-after-free with AIO

[Jan Kara]

Running AIO is pinning inode in memory using file reference. Once AIO
is completed using aio_complete(), file reference is put and inode can
be freed from memory. So we have to be sure that calling aio_complete()
is the last thing we do with the inode.

CC: Christoph Hellwig <hch@infradead.org>
CC: Jens Axboe <axboe@kernel.dk>
CC: Jeff Moyer <jmoyer@redhat.com>
CC: stable@vger.kernel.org
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/direct-io.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/direct-io.c b/fs/direct-io.c
index cf5b44b..f853263 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -261,9 +261,9 @@ static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret, bool is
 		dio->end_io(dio->iocb, offset, transferred,
 			    dio->private, ret, is_async);
 	} else {
+		inode_dio_done(dio->inode);
 		if (is_async)
 			aio_complete(dio->iocb, ret, 0);
-		inode_dio_done(dio->inode);
 	}
 
 	return ret;
-- 
1.7.1

Re: [PATCH 0/4 v2] Fix possible use after free with AIO

[Al Viro]

On Wed, Jan 30, 2013 at 12:27:57AM +0100, Jan Kara wrote:
> 
>   Hi,
> 
>   since nobody seem to have picked up any of the patches (at least
> nobody told me so), I've added acks I received to the patches and I'm
> sending them to Al for merging. Al, can you please merge these? Thanks.

VFS part (4/4) picked; IMO at least ext* and xfs should go through the
filesystem trees.  If ocfs2 folks don't pick fs/ocfs2 part, I'll grab
it as well - not sure how active their tree is these days...

Re: [PATCH 0/4 v2] Fix possible use after free with AIO

[Li Zefan]

On 2013/1/30 22:45, Al Viro wrote:
> On Wed, Jan 30, 2013 at 12:27:57AM +0100, Jan Kara wrote:
>>
>>   Hi,
>>
>>   since nobody seem to have picked up any of the patches (at least
>> nobody told me so), I've added acks I received to the patches and I'm
>> sending them to Al for merging. Al, can you please merge these? Thanks.
> 
> VFS part (4/4) picked; IMO at least ext* and xfs should go through the
> filesystem trees.  If ocfs2 folks don't pick fs/ocfs2 part, I'll grab
> it as well - not sure how active their tree is these days...

I would say just grab it.

We've been sending bug fixes to ocfs2 mailing list since Aug 2012, but none
was pushed into upstream.

Re: [PATCH 0/4 v2] Fix possible use after free with AIO

[Joel Becker]

On Wed, Jan 30, 2013 at 02:45:35PM +0000, Al Viro wrote:
> On Wed, Jan 30, 2013 at 12:27:57AM +0100, Jan Kara wrote:
> > 
> >   Hi,
> > 
> >   since nobody seem to have picked up any of the patches (at least
> > nobody told me so), I've added acks I received to the patches and I'm
> > sending them to Al for merging. Al, can you please merge these? Thanks.
> 
> VFS part (4/4) picked; IMO at least ext* and xfs should go through the
> filesystem trees.  If ocfs2 folks don't pick fs/ocfs2 part, I'll grab
> it as well - not sure how active their tree is these days...

	I thought akpm had this through -mm.  I acked it there.

Joel

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