The driver was clearing its struct usb_device pointer, which it used as an inverted disconnected flag, before deregistering the character device and without serialising against racing release().
This could lead to a use-after-free if a racing release() callback observes the cleared pointer and frees the driver data before disconnect() is finished with it.
This could also lead to NULL-pointer dereferences in a racing open().
Fixes: f08812d5eb8f ("USB: FIx locks and urb->status in adutux (updated)") Cc: stable stable@vger.kernel.org # 2.6.24 Reported-by: syzbot+0243cb250a51eeefb8cc@syzkaller.appspotmail.com Tested-by: syzbot+0243cb250a51eeefb8cc@syzkaller.appspotmail.com Signed-off-by: Johan Hovold johan@kernel.org --- drivers/usb/misc/adutux.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/misc/adutux.c b/drivers/usb/misc/adutux.c index 344d523b0502..bcc138990e2f 100644 --- a/drivers/usb/misc/adutux.c +++ b/drivers/usb/misc/adutux.c @@ -762,14 +762,15 @@ static void adu_disconnect(struct usb_interface *interface)
dev = usb_get_intfdata(interface);
- mutex_lock(&dev->mtx); /* not interruptible */ - dev->udev = NULL; /* poison */ usb_deregister_dev(interface, &adu_class); - mutex_unlock(&dev->mtx);
mutex_lock(&adutux_mutex); usb_set_intfdata(interface, NULL);
+ mutex_lock(&dev->mtx); /* not interruptible */ + dev->udev = NULL; /* poison */ + mutex_unlock(&dev->mtx); + /* if the device is not opened, then we clean up right now */ if (!dev->open_count) adu_delete(dev);
The driver was 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 statements in the completion handlers which relies on said pointer.
The pointer was also dereferenced unconditionally in a dev_dbg statement release() something which would lead to a NULL-deref whenever a device was disconnected before the final character-device close if debugging was enabled.
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: 1ef37c6047fe ("USB: adutux: remove custom debug macro and module parameter") Fixes: 66d4bc30d128 ("USB: adutux: remove custom debug macro") Cc: stable stable@vger.kernel.org # 3.12 Signed-off-by: Johan Hovold johan@kernel.org --- drivers/usb/misc/adutux.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/misc/adutux.c b/drivers/usb/misc/adutux.c index bcc138990e2f..f9efec719359 100644 --- a/drivers/usb/misc/adutux.c +++ b/drivers/usb/misc/adutux.c @@ -75,6 +75,7 @@ struct adu_device { char serial_number[8];
int open_count; /* number of times this port has been opened */ + unsigned long disconnected:1;
char *read_buffer_primary; int read_buffer_length; @@ -116,7 +117,7 @@ static void adu_abort_transfers(struct adu_device *dev) { unsigned long flags;
- if (dev->udev == NULL) + if (dev->disconnected) return;
/* shutdown transfer */ @@ -243,7 +244,7 @@ static int adu_open(struct inode *inode, struct file *file) }
dev = usb_get_intfdata(interface); - if (!dev || !dev->udev) { + if (!dev) { retval = -ENODEV; goto exit_no_device; } @@ -326,7 +327,7 @@ static int adu_release(struct inode *inode, struct file *file) }
adu_release_internal(dev); - if (dev->udev == NULL) { + if (dev->disconnected) { /* the device was unplugged before the file was released */ if (!dev->open_count) /* ... and we're the last user */ adu_delete(dev); @@ -354,7 +355,7 @@ static ssize_t adu_read(struct file *file, __user char *buffer, size_t count, return -ERESTARTSYS;
/* 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 exit; @@ -518,7 +519,7 @@ static ssize_t adu_write(struct file *file, const __user char *buffer, goto exit_nolock;
/* 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 exit; @@ -764,11 +765,14 @@ static void adu_disconnect(struct usb_interface *interface)
usb_deregister_dev(interface, &adu_class);
+ usb_poison_urb(dev->interrupt_in_urb); + usb_poison_urb(dev->interrupt_out_urb); + mutex_lock(&adutux_mutex); usb_set_intfdata(interface, NULL);
mutex_lock(&dev->mtx); /* not interruptible */ - dev->udev = NULL; /* poison */ + dev->disconnected = 1; mutex_unlock(&dev->mtx);
/* if the device is not opened, then we clean up right now */
linux-stable-mirror@lists.linaro.org
-
Johan Hovold