diff options
| author | Oliver Neukum <oneukum@suse.de> | 2013-03-12 17:52:42 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-13 03:33:05 +0400 |
| commit | c0f5ecee4e741667b2493c742b60b6218d40b3aa (patch) | |
| tree | 64f1a695a53a28eaaebe90a0816746d28ab63511 /drivers | |
| parent | a57e82a18779ab8a5e5a1f5841cef937cf578913 (diff) | |
| download | linux-c0f5ecee4e741667b2493c742b60b6218d40b3aa.tar.xz | |
USB: cdc-wdm: fix buffer overflow
The buffer for responses must not overflow.
If this would happen, set a flag, drop the data and return
an error after user space has read all remaining data.
Signed-off-by: Oliver Neukum <oliver@neukum.org>
CC: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/class/cdc-wdm.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index 5f0cb417b736..122d056d96d5 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -56,6 +56,7 @@ MODULE_DEVICE_TABLE (usb, wdm_ids); #define WDM_RESPONDING 7 #define WDM_SUSPENDING 8 #define WDM_RESETTING 9 +#define WDM_OVERFLOW 10 #define WDM_MAX 16 @@ -155,6 +156,7 @@ static void wdm_in_callback(struct urb *urb) { struct wdm_device *desc = urb->context; int status = urb->status; + int length = urb->actual_length; spin_lock(&desc->iuspin); clear_bit(WDM_RESPONDING, &desc->flags); @@ -185,9 +187,17 @@ static void wdm_in_callback(struct urb *urb) } desc->rerr = status; - desc->reslength = urb->actual_length; - memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength); - desc->length += desc->reslength; + if (length + desc->length > desc->wMaxCommand) { + /* The buffer would overflow */ + set_bit(WDM_OVERFLOW, &desc->flags); + } else { + /* we may already be in overflow */ + if (!test_bit(WDM_OVERFLOW, &desc->flags)) { + memmove(desc->ubuf + desc->length, desc->inbuf, length); + desc->length += length; + desc->reslength = length; + } + } skip_error: wake_up(&desc->wait); @@ -435,6 +445,11 @@ retry: rv = -ENODEV; goto err; } + if (test_bit(WDM_OVERFLOW, &desc->flags)) { + clear_bit(WDM_OVERFLOW, &desc->flags); + rv = -ENOBUFS; + goto err; + } i++; if (file->f_flags & O_NONBLOCK) { if (!test_bit(WDM_READ, &desc->flags)) { @@ -478,6 +493,7 @@ retry: spin_unlock_irq(&desc->iuspin); goto retry; } + if (!desc->reslength) { /* zero length read */ dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__); clear_bit(WDM_READ, &desc->flags); @@ -1004,6 +1020,7 @@ static int wdm_post_reset(struct usb_interface *intf) struct wdm_device *desc = wdm_find_device(intf); int rv; + clear_bit(WDM_OVERFLOW, &desc->flags); clear_bit(WDM_RESETTING, &desc->flags); rv = recover_from_urb_loss(desc); mutex_unlock(&desc->wlock); |