Interesting issues with CCMP
kyle at engsoc.carleton.ca
Fri Sep 24 20:08:34 EDT 2004
On Fri, Sep 24, 2004 at 04:28:30PM -0700, James Woo wrote:
> It's a Linksys WAP54g bug. It's not clearing the PwrMgt bit (bit 12) when
> the AAD. You're losing your multicast packets when PwrMgt bit is set. To
> become bug-compatible,
> change line 818 in hostap_crypt_ccmp.c from
> aad = pos & 0xc7; to aad = pos & 0xe7;
> and then your problem should go away.
> James Woo
> P.S. Linksys WAP54g has similar CCMP problem with fragmentation too.
> It's clearing the fragment number when constructing the AAD. To verify the
> problem, you'll
> see no data traffic when fragmentation is enabled (for example,
> fragmentation = 256).
Ick. I guess I'll have to hope for a firmware upgrade from linksys.
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