Linux-USB Archive on lore.kernel.org
 help / color / Atom feed
From: Valentin Vidic <vvidic@valentin-vidic.from.hr>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Oliver Neukum <oneukum@suse.com>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Valentin Vidic <vvidic@valentin-vidic.from.hr>,
	syzbot+0761012cebf7bdb38137@syzkaller.appspotmail.com
Subject: [PATCH] usb: iowarrior: fix access to freed data structure
Date: Wed,  9 Oct 2019 00:23:07 +0200
Message-ID: <20191008222307.18587-1-vvidic@valentin-vidic.from.hr> (raw)

struct iowarrior gets freed prematurely in iowarrior_release while
it is still being referenced from usb_interface, so let only
iowarrior_disconnect call iowarrior_delete.

Fixes: KMSAN: uninit-value in iowarrior_disconnect
Reported-by: syzbot+0761012cebf7bdb38137@syzkaller.appspotmail.com
Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr>
---
 drivers/usb/misc/iowarrior.c | 35 +++++++++++++++--------------------
 1 file changed, 15 insertions(+), 20 deletions(-)

diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
index f5bed9f29e56..0492ea76c4bf 100644
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -638,7 +638,6 @@ static int iowarrior_open(struct inode *inode, struct file *file)
 static int iowarrior_release(struct inode *inode, struct file *file)
 {
 	struct iowarrior *dev;
-	int retval = 0;
 
 	dev = file->private_data;
 	if (!dev)
@@ -650,27 +649,23 @@ static int iowarrior_release(struct inode *inode, struct file *file)
 	mutex_lock(&dev->mutex);
 
 	if (dev->opened <= 0) {
-		retval = -ENODEV;	/* close called more than once */
 		mutex_unlock(&dev->mutex);
-	} else {
-		dev->opened = 0;	/* we're closing now */
-		retval = 0;
-		if (dev->present) {
-			/*
-			   The device is still connected so we only shutdown
-			   pending read-/write-ops.
-			 */
-			usb_kill_urb(dev->int_in_urb);
-			wake_up_interruptible(&dev->read_wait);
-			wake_up_interruptible(&dev->write_wait);
-			mutex_unlock(&dev->mutex);
-		} else {
-			/* The device was unplugged, cleanup resources */
-			mutex_unlock(&dev->mutex);
-			iowarrior_delete(dev);
-		}
+		return -ENODEV;	/* close called more than once */
 	}
-	return retval;
+
+	dev->opened = 0;	/* we're closing now */
+	if (dev->present) {
+		/*
+		 * The device is still connected so we only shutdown
+		 * pending read/write ops.
+		 */
+		usb_kill_urb(dev->int_in_urb);
+		wake_up_interruptible(&dev->read_wait);
+		wake_up_interruptible(&dev->write_wait);
+	}
+
+	mutex_unlock(&dev->mutex);
+	return 0;
 }
 
 static __poll_t iowarrior_poll(struct file *file, poll_table * wait)
-- 
2.20.1


             reply index

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-08 22:23 Valentin Vidic [this message]
2019-10-09  7:36 ` Johan Hovold

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191008222307.18587-1-vvidic@valentin-vidic.from.hr \
    --to=vvidic@valentin-vidic.from.hr \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=oneukum@suse.com \
    --cc=syzbot+0761012cebf7bdb38137@syzkaller.appspotmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-USB Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-usb/0 linux-usb/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-usb linux-usb/ https://lore.kernel.org/linux-usb \
		linux-usb@vger.kernel.org
	public-inbox-index linux-usb

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-usb


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git