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| author | Johan Hovold <johan@kernel.org> | 2019-09-25 11:29:13 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-04 11:02:59 +0200 |
| commit | b2fa7baee744fde746c17bc1860b9c6f5c2eebb7 (patch) | |
| tree | e5ca4d7fb071be16b0366348cf5b125ca75c7782 | |
| parent | 44efc269db7929f6275a1fa927ef082e533ecde0 (diff) | |
| download | lwn-b2fa7baee744fde746c17bc1860b9c6f5c2eebb7.tar.gz lwn-b2fa7baee744fde746c17bc1860b9c6f5c2eebb7.zip | |
USB: adutux: fix NULL-derefs on disconnect
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>
Link: https://lore.kernel.org/r/20190925092913.8608-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/misc/adutux.c | 16 |
1 files 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 */ |