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authorOliver Neukum <oneukum@suse.de>2013-03-12 14:52:42 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-12 16:33:05 -0700
commitc0f5ecee4e741667b2493c742b60b6218d40b3aa (patch)
tree64f1a695a53a28eaaebe90a0816746d28ab63511 /drivers/usb/class/cdc-wdm.c
parenta57e82a18779ab8a5e5a1f5841cef937cf578913 (diff)
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/usb/class/cdc-wdm.c')
-rw-r--r--drivers/usb/class/cdc-wdm.c23
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);