[patch 19/28] USB: devio: Properly do access_ok() checks

[Greg KH]

2.6.27-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Michael Buesch <mb@xxxxxxxxx>

commit 18753ebc8a98efe0e8ff6167afb31cef220c8e50 upstream.

access_ok() checks must be done on every part of the userspace structure
that is accessed. If access_ok() on one part of the struct succeeded, it
does not imply it will succeed on other parts of the struct. (Does
depend on the architecture implementation of access_ok()).

This changes the __get_user() users to first check access_ok() on the
data structure.

Signed-off-by: Michael Buesch <mb@xxxxxxxxx>
Cc: Pete Zaitcev <zaitcev@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/usb/core/devio.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1305,7 +1305,8 @@ static int get_urb32(struct usbdevfs_urb
 		     struct usbdevfs_urb32 __user *uurb)
 {
 	__u32  uptr;
-	if (get_user(kurb->type, &uurb->type) ||
+	if (!access_ok(VERIFY_READ, uurb, sizeof(*uurb)) ||
+	    __get_user(kurb->type, &uurb->type) ||
 	    __get_user(kurb->endpoint, &uurb->endpoint) ||
 	    __get_user(kurb->status, &uurb->status) ||
 	    __get_user(kurb->flags, &uurb->flags) ||
@@ -1522,8 +1523,9 @@ static int proc_ioctl_compat(struct dev_
 	u32 udata;
 
 	uioc = compat_ptr((long)arg);
-	if (get_user(ctrl.ifno, &uioc->ifno) ||
-	    get_user(ctrl.ioctl_code, &uioc->ioctl_code) ||
+	if (!access_ok(VERIFY_READ, uioc, sizeof(*uioc)) ||
+	    __get_user(ctrl.ifno, &uioc->ifno) ||
+	    __get_user(ctrl.ioctl_code, &uioc->ioctl_code) ||
 	    __get_user(udata, &uioc->data))
 		return -EFAULT;
 	ctrl.data = compat_ptr(udata);


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