Re: [RFC PATCH] binfmt_elf: Extract .note.gnu.property from an ELF file

[Pavel Machek <pavel@ucw.cz>]

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Hi!


> > +static int scan(u8 *buf, u32 buf_size, int item_size, test_item_fn test_item,
> > +               next_item_fn next_item, u32 *arg, u32 type, u32 *pos)
> > +{
> > +       int found = 0;
> > +       u8 *p, *max;
> > +
> > +       max = buf + buf_size;
> > +       if (max < buf)
> > +               return 0;
> 
> How can this ever legitimately happen? If it can't, perhaps you meant
> to put a WARN_ON_ONCE() or something like that here?
> Also, computing out-of-bounds pointers is UB (section 6.5.6 of C99:
> "If both the pointer operand and the result point to elements of the
> same array object, or one past the last element of the array object,
> the evaluation shall not produce an overflow; otherwise, the behavior
> is undefined."), and if the addition makes the pointer wrap, that's
> certainly out of bounds; so I don't think this condition can trigger
> without UB.

Kernel assumes sane compiler. We pass flags to get it... C99 does not
quite apply here.
								Pavel
								
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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