diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2012-07-19 16:08:21 -0400 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2012-07-20 11:24:23 +0200 |
| commit | 668160e5a80536251b4931a332dfe34d6ec2aeb7 (patch) | |
| tree | 326dff1f73e54f8f57a49b090a9f0411cd22dfdb | |
| parent | 61c901c56905256a4a4d7c2af92d66200a2ee7f2 (diff) | |
HID: usbhid: fix use-after-free bug
This patch (as1592) fixes an obscure problem in the usbhid driver.
Under some circumstances, a control or interrupt-OUT URB can be
submitted twice. This will happen if the first submission fails; the
queue pointers aren't updated, so the next time the queue is restarted
the same URB will be submitted again.
The problem is that raw_report gets deallocated during the first
submission. The second submission will then dereference and try to
free an already-freed region of memory. The patch fixes the problem
by setting raw_report to NULL when it is deallocated and checking for
NULL before dereferencing it.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| -rw-r--r-- | drivers/hid/usbhid/hid-core.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c index 482f936fc29..6b9bad54070 100644 --- a/drivers/hid/usbhid/hid-core.c +++ b/drivers/hid/usbhid/hid-core.c @@ -331,9 +331,12 @@ static int hid_submit_out(struct hid_device *hid) usbhid->urbout->transfer_buffer_length = ((report->size - 1) >> 3) + 1 + (report->id > 0); usbhid->urbout->dev = hid_to_usb_dev(hid); - memcpy(usbhid->outbuf, raw_report, - usbhid->urbout->transfer_buffer_length); - kfree(raw_report); + if (raw_report) { + memcpy(usbhid->outbuf, raw_report, + usbhid->urbout->transfer_buffer_length); + kfree(raw_report); + usbhid->out[usbhid->outtail].raw_report = NULL; + } dbg_hid("submitting out urb\n"); @@ -362,8 +365,11 @@ static int hid_submit_ctrl(struct hid_device *hid) if (dir == USB_DIR_OUT) { usbhid->urbctrl->pipe = usb_sndctrlpipe(hid_to_usb_dev(hid), 0); usbhid->urbctrl->transfer_buffer_length = len; - memcpy(usbhid->ctrlbuf, raw_report, len); - kfree(raw_report); + if (raw_report) { + memcpy(usbhid->ctrlbuf, raw_report, len); + kfree(raw_report); + usbhid->ctrl[usbhid->ctrltail].raw_report = NULL; + } } else { int maxpacket, padlen; |