Date: Wed, 2 May 2012 16:14:10 +0200 From: Lukas Odzioba <lukas.odzioba@...il.com> To: john-dev@...ts.openwall.com Subject: Re: wpapsk.h warnings 2012/5/2 Solar Designer <solar@...nwall.com>: > Lukas, magnum - > > On Tue, May 01, 2012 at 11:57:05PM +0200, magnum wrote: >> I get these warnings when building. The first one looks like an actual >> bug to me, or maybe I misunderstand the code: >> >> In file included from opencl_wpapsk_fmt.c:15:0: >> wpapsk.h: In function ???decode_hccap???: >> wpapsk.h:102:9: warning: array subscript is above array bounds >> [-Warray-bounds] >> >> The array is char but you write all the way to 118 * 3, no? > > I looked into this yesterday. The out-of-bounds writes look intentional > (I think they're still within the struct, although I did not verify > that), but there's assumption that they're permitted and that the struct > is packed. We can only ensure the latter with specific compilers (such > as with gcc's __attribute__((packed)), which we'll need to specify), > although in practice I am not aware of cases of compilers inserting > padding between fields of type char. > > I think it'd be best to rewrite this, maybe by using a union - one > sufficiently large array union'ed with a struct - although that still > depends on the struct being packed. > > Alexander Code may look weird but it was intentional. I didn't want to parse/copy each parameter separately. I added in hccap2john and in _fmt files asserts(sizeof(hccap)==HCCAP_SIZE); I am not absolutely sure but this in my opinion catch out of struct error if it may occur. If necessary I could rewrite this method in "proper" way. Lukas
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