USB: devio: Properly do access_ok() checks

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@bu3sch.de>
Cc: stable <stable@kernel.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 38b8bce782d6..e192fa05f8a1 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1321,7 +1321,8 @@ static int get_urb32(struct usbdevfs_urb *kurb,
                      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) ||
@@ -1536,8 +1537,9 @@ static int proc_ioctl_compat(struct dev_state *ps, compat_uptr_t arg)
         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);