From: Johan Hovold <johan@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org, Alan Stern <stern@rowland.harvard.edu>,
Oliver Neukum <oneukum@suse.com>,
Juergen Stuber <starblue@users.sourceforge.net>,
legousb-devel@lists.sourceforge.net,
Johan Hovold <johan@kernel.org>, stable <stable@vger.kernel.org>
Subject: [PATCH RESEND 3/4] USB: legousbtower: fix potential NULL-deref on disconnect
Date: Thu, 19 Sep 2019 10:30:38 +0200 [thread overview]
Message-ID: <20190919083039.30898-4-johan@kernel.org> (raw)
In-Reply-To: <20190919083039.30898-1-johan@kernel.org>
The driver is using its struct usb_device pointer as an inverted
disconnected flag, but was setting it to NULL before making sure all
completion handlers had run. This could lead to a NULL-pointer
dereference in a number of dev_dbg and dev_err statements in the
completion handlers which relies on said pointer.
Fix this by unconditionally stopping all I/O and preventing
resubmissions by poisoning the interrupt URBs at disconnect and using a
dedicated disconnected flag.
This also makes sure that all I/O has completed by the time the
disconnect callback returns.
Fixes: 9d974b2a06e3 ("USB: legousbtower.c: remove err() usage")
Fixes: fef526cae700 ("USB: legousbtower: remove custom debug macro")
Fixes: 4dae99638097 ("USB: legotower: remove custom debug macro and module parameter")
Cc: stable <stable@vger.kernel.org> # 3.5
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/usb/misc/legousbtower.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)
diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c
index 773e4188f336..4fa999882635 100644
--- a/drivers/usb/misc/legousbtower.c
+++ b/drivers/usb/misc/legousbtower.c
@@ -190,6 +190,7 @@ struct lego_usb_tower {
unsigned char minor; /* the starting minor number for this device */
int open_count; /* number of times this port has been opened */
+ unsigned long disconnected:1;
char* read_buffer;
size_t read_buffer_length; /* this much came in */
@@ -289,8 +290,6 @@ static inline void lego_usb_tower_debug_data(struct device *dev,
*/
static inline void tower_delete (struct lego_usb_tower *dev)
{
- tower_abort_transfers (dev);
-
/* free data structures */
usb_free_urb(dev->interrupt_in_urb);
usb_free_urb(dev->interrupt_out_urb);
@@ -430,7 +429,8 @@ static int tower_release (struct inode *inode, struct file *file)
retval = -ENODEV;
goto unlock_exit;
}
- if (dev->udev == NULL) {
+
+ if (dev->disconnected) {
/* the device was unplugged before the file was released */
/* unlock here as tower_delete frees dev */
@@ -466,10 +466,9 @@ static void tower_abort_transfers (struct lego_usb_tower *dev)
if (dev->interrupt_in_running) {
dev->interrupt_in_running = 0;
mb();
- if (dev->udev)
- usb_kill_urb (dev->interrupt_in_urb);
+ usb_kill_urb(dev->interrupt_in_urb);
}
- if (dev->interrupt_out_busy && dev->udev)
+ if (dev->interrupt_out_busy)
usb_kill_urb(dev->interrupt_out_urb);
}
@@ -505,7 +504,7 @@ static __poll_t tower_poll (struct file *file, poll_table *wait)
dev = file->private_data;
- if (!dev->udev)
+ if (dev->disconnected)
return EPOLLERR | EPOLLHUP;
poll_wait(file, &dev->read_wait, wait);
@@ -552,7 +551,7 @@ static ssize_t tower_read (struct file *file, char __user *buffer, size_t count,
}
/* verify that the device wasn't unplugged */
- if (dev->udev == NULL) {
+ if (dev->disconnected) {
retval = -ENODEV;
pr_err("No device or device unplugged %d\n", retval);
goto unlock_exit;
@@ -638,7 +637,7 @@ static ssize_t tower_write (struct file *file, const char __user *buffer, size_t
}
/* verify that the device wasn't unplugged */
- if (dev->udev == NULL) {
+ if (dev->disconnected) {
retval = -ENODEV;
pr_err("No device or device unplugged %d\n", retval);
goto unlock_exit;
@@ -748,7 +747,7 @@ static void tower_interrupt_in_callback (struct urb *urb)
resubmit:
/* resubmit if we're still running */
- if (dev->interrupt_in_running && dev->udev) {
+ if (dev->interrupt_in_running) {
retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
if (retval)
dev_err(&dev->udev->dev,
@@ -813,6 +812,7 @@ static int tower_probe (struct usb_interface *interface, const struct usb_device
dev->udev = udev;
dev->open_count = 0;
+ dev->disconnected = 0;
dev->read_buffer = NULL;
dev->read_buffer_length = 0;
@@ -938,6 +938,10 @@ static void tower_disconnect (struct usb_interface *interface)
/* give back our minor and prevent further open() */
usb_deregister_dev (interface, &tower_class);
+ /* stop I/O */
+ usb_poison_urb(dev->interrupt_in_urb);
+ usb_poison_urb(dev->interrupt_out_urb);
+
mutex_lock(&dev->lock);
/* if the device is not opened, then we clean up right now */
@@ -945,7 +949,7 @@ static void tower_disconnect (struct usb_interface *interface)
mutex_unlock(&dev->lock);
tower_delete (dev);
} else {
- dev->udev = NULL;
+ dev->disconnected = 1;
/* wake up pollers */
wake_up_interruptible_all(&dev->read_wait);
wake_up_interruptible_all(&dev->write_wait);
--
2.23.0
next prev parent reply other threads:[~2019-09-19 8:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-19 8:30 [PATCH RESEND 0/4] USB: legousbtower: misc fixes Johan Hovold
2019-09-19 8:30 ` [PATCH RESEND 1/4] USB: legousbtower: fix slab info leak at probe Johan Hovold
2019-09-19 8:30 ` [PATCH RESEND 2/4] USB: legousbtower: fix deadlock on disconnect Johan Hovold
2019-09-19 8:30 ` Johan Hovold [this message]
2019-09-19 8:30 ` [PATCH RESEND 4/4] USB: legousbtower: fix open after failed reset request Johan Hovold
Reply instructions:
You may reply publicly 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=20190919083039.30898-4-johan@kernel.org \
--to=johan@kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=legousb-devel@lists.sourceforge.net \
--cc=linux-usb@vger.kernel.org \
--cc=oneukum@suse.com \
--cc=stable@vger.kernel.org \
--cc=starblue@users.sourceforge.net \
--cc=stern@rowland.harvard.edu \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).