On Tue, Jan 10, 2017 at 11:23 AM, Kees Cook <keesc...@chromium.org> wrote:
> On Tue, Jan 10, 2017 at 10:28 AM, Julia Lawall <julia.law...@lip6.fr> wrote:
>>> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2159
>>> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2257
>>> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2302
>>> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2342
>>> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2365
>>> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2406
>>> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2439
>>> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2491
>>
>> Do you want the above results? They have the form:
>>
>> if (copy_from_user(&t, useraddr, sizeof(t)))
>>
>> My reasoning was that there could be no problem here, because the size is
>> the size of the destination structure. It doesn't depend on user level data.
>
> They're likely false positives, but it does follow the pattern of
> reading the same userspace location twice:
>
> if (copy_from_user(&cmd, useraddr, sizeof(cmd)))
> return -EFAULT;
>
> switch (cmd) {
> case CHELSIO_SET_QSET_PARAMS:{
> int i;
> struct qset_params *q;
> struct ch_qset_params t;
> int q1 = pi->first_qset;
> int nqsets = pi->nqsets;
>
> if (!capable(CAP_NET_ADMIN))
> return -EPERM;
> if (copy_from_user(&t, useraddr, sizeof(t)))
> return -EFAULT;
>
> If there is any logic that examines cmd (u32) and operates on t
> (struct ch_qset_params), there could be a flaw. It doesn't look like
> it here, but a "correct" version of this would be:
>
> if (copy_from_user(&t, useraddr, sizeof(t)))
> return -EFAULT;
> t.cmd = cmd;
Errr, no. Think-o. Should be "if (t.cmd != cmd) { freak out }"...
-Kees
--
Kees Cook
Nexus Security
