[PATCH] Updates for stricter automatic memcpy bounds checking

Arik Nemtsov arik at wizery.com
Mon Apr 13 04:13:31 EDT 2015


On Sun, Apr 12, 2015 at 11:26 PM, Nick Kralevich <nnk at google.com> wrote:
> On Sun, Apr 12, 2015 at 12:53 AM, Arik Nemtsov <arik at wizery.com> wrote:
>> >                 struct {
>> > +                       u8 unused;
>> >                         /* only variable items: SSID, Supported rates */
>> > -                       u8 variable[0];
>> > +                       u8 variable[];
>> >                 } STRUCT_PACKED probe_req;
>>
>> Isn't this introducing a bug? This piece of code will now point to the
>> wrong location I believe:
>>
>> ie = mgmt->u.probe_req.variable;
>
> Yes, I believe this is a bug. I updated the patch to avoid changing
> this structure, since I couldn't figure out a clean way to fix it
> properly. gcc doesn't support the use of a flexible array element as
> the only element of a structure
> (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53548)

Looks good. Yea I guess the simplest solution is to just avoid
verification here for now.

Arik


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