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SubjectRe: [PATCH 2/2] x86: ia32_signal: remove unnecessary padding
H. Peter Anvin writes:
> Hiroshi Shimamoto wrote:
> > H. Peter Anvin wrote:
> >> Mikael Pettersson wrote:
> >>> It does cause each signal delivery to leak 2 uninitialised
> >>> kernel bytes to the end of retcode[], which seems unnecessary.
> >> Not just unnecessary, it is a huge no-no for security.
> >
> > Am I missing important thing?
> > The frame->retcode is 8 bytes and packed structure with padding
> > is 10 bytes each, and the code is copied to user stack 8 bytes only.
> >
> > err |= __copy_to_user(frame->retcode, &code, 8);
> >
> > I don't think the behavior is changed.
> >
>
> Ah, nevermind, then. Then it fine, obviously.

Agreed. I wonder how on earth those templates ended
up as 10 bytes large when retcode[] always has been
8 bytes.


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