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From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Maxim Patlasov <MPatlasov@parallels.com>,
	Robert Baldyga <r.baldyga@samsung.com>,
	Michal Nazarewicz <mina86@mina86.com>,
	Felipe Balbi <balbi@ti.com>,
	linux-aio@kvack.org, linux-fsdevel@vger.kernel.org,
	stable@vger.kernel.org
Subject: [PATCH 06/12] gadgetfs: use-after-free in ->aio_read()
Date: Mon, 23 Feb 2015 10:00:30 -0800	[thread overview]
Message-ID: <1424714436-19371-7-git-send-email-hch@lst.de> (raw)
In-Reply-To: <1424714436-19371-1-git-send-email-hch@lst.de>

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

AIO_PREAD requests call ->aio_read() with iovec on caller's stack, so if
we are going to access it asynchronously, we'd better get ourselves
a copy - the one on kernel stack of aio_run_iocb() won't be there
anymore.  function/f_fs.c take care of doing that, legacy/inode.c
doesn't...

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 drivers/usb/gadget/legacy/inode.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index db49ec4..9fbbaa0 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -566,7 +566,6 @@ static ssize_t ep_copy_to_user(struct kiocb_priv *priv)
 		if (total == 0)
 			break;
 	}
-
 	return len;
 }
 
@@ -585,6 +584,7 @@ static void ep_user_copy_worker(struct work_struct *work)
 	aio_complete(iocb, ret, ret);
 
 	kfree(priv->buf);
+	kfree(priv->iv);
 	kfree(priv);
 }
 
@@ -605,6 +605,7 @@ static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
 	 */
 	if (priv->iv == NULL || unlikely(req->actual == 0)) {
 		kfree(req->buf);
+		kfree(priv->iv);
 		kfree(priv);
 		iocb->private = NULL;
 		/* aio_complete() reports bytes-transferred _and_ faults */
@@ -640,7 +641,7 @@ ep_aio_rwtail(
 	struct usb_request	*req;
 	ssize_t			value;
 
-	priv = kmalloc(sizeof *priv, GFP_KERNEL);
+	priv = kzalloc(sizeof *priv, GFP_KERNEL);
 	if (!priv) {
 		value = -ENOMEM;
 fail:
@@ -649,7 +650,14 @@ fail:
 	}
 	iocb->private = priv;
 	priv->iocb = iocb;
-	priv->iv = iv;
+	if (iv) {
+		priv->iv = kmemdup(iv, nr_segs * sizeof(struct iovec),
+				   GFP_KERNEL);
+		if (!priv->iv) {
+			kfree(priv);
+			goto fail;
+		}
+	}
 	priv->nr_segs = nr_segs;
 	INIT_WORK(&priv->work, ep_user_copy_worker);
 
@@ -689,6 +697,7 @@ fail:
 	mutex_unlock(&epdata->lock);
 
 	if (unlikely(value)) {
+		kfree(priv->iv);
 		kfree(priv);
 		put_ep(epdata);
 	} else
-- 
1.9.1


  parent reply	other threads:[~2015-02-23 18:02 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-23 18:00 [RFC] split struct kiocb Christoph Hellwig
2015-02-23 18:00 ` [PATCH 01/12] new helper: dup_iter() Christoph Hellwig
2015-02-23 18:00 ` [PATCH 02/12] move iov_iter.c from mm/ to lib/ Christoph Hellwig
2015-02-23 18:00 ` [PATCH 03/12] gadget/function/f_fs.c: close leaks Christoph Hellwig
2015-02-23 18:00 ` [PATCH 04/12] gadget/function/f_fs.c: use put iov_iter into io_data Christoph Hellwig
2015-02-23 18:00 ` [PATCH 05/12] gadget/function/f_fs.c: switch to ->{read,write}_iter() Christoph Hellwig
2015-02-23 18:00 ` Christoph Hellwig [this message]
2015-03-08 10:07   ` [PATCH 06/12] gadgetfs: use-after-free in ->aio_read() Ming Lei
2015-03-09 15:18     ` Michal Nazarewicz
2015-02-23 18:00 ` [PATCH 07/12] gadget: switch ep_io_operations to ->read_iter/->write_iter Christoph Hellwig
2015-02-23 18:00 ` [PATCH 08/12] fs: remove ki_nbytes Christoph Hellwig
2015-02-23 18:00 ` [PATCH 09/12] fuse: handle synchronous iocbs internally Christoph Hellwig
2015-03-06  2:54   ` Maxim Patlasov
2015-02-23 18:00 ` [PATCH 10/12] fs: don't allow to complete sync iocbs through aio_complete Christoph Hellwig
2015-02-23 18:00 ` [PATCH 11/12] fs: split generic and aio kiocb Christoph Hellwig
2015-02-23 18:00 ` [PATCH 12/12] fs: move struct kiocb to fs.h Christoph Hellwig
2015-02-23 21:20 ` [RFC] split struct kiocb Al Viro
2015-02-23 21:22   ` Christoph Hellwig
2015-02-23 21:39     ` Al Viro
2015-02-24  3:47       ` Al Viro
2015-02-23 21:23   ` Felipe Balbi
2015-02-23 21:42     ` Al Viro
2015-02-23 21:50       ` Felipe Balbi
2015-02-25 17:13   ` Felipe Balbi

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