Messages in this thread | | | Date | Thu, 16 Jul 2015 08:40:31 +0200 | Subject | Re: [PATCH] asm-generic: {get,put}_user ptr argument evaluate only 1 time | From | Geert Uytterhoeven <> |
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Hi Sato-san,
On Thu, Jul 16, 2015 at 7:15 AM, Yoshinori Sato <ysato@users.sourceforge.jp> wrote: > Current implemantation ptr argument evaluate 2 times. > It'll be an unexpected result. > > Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
> --- > include/asm-generic/uaccess.h | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h > index 72d8803..1b813fb 100644 > --- a/include/asm-generic/uaccess.h > +++ b/include/asm-generic/uaccess.h > @@ -163,9 +163,10 @@ static inline __must_check long __copy_to_user(void __user *to, > > #define put_user(x, ptr) \ > ({ \ > + __typeof__((ptr)) __p = (ptr); \ > might_fault(); \ > - access_ok(VERIFY_WRITE, ptr, sizeof(*ptr)) ? \ > - __put_user(x, ptr) : \ > + access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \ > + __put_user(x, __p) : \
For safety, you may want to change "x" to "(x") while at it.
> -EFAULT; \ > }) > > @@ -225,9 +226,10 @@ extern int __put_user_bad(void) __attribute__((noreturn)); > > #define get_user(x, ptr) \ > ({ \ > + __typeof__((ptr)) __p = (ptr); \ > might_fault(); \ > - access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \ > - __get_user(x, ptr) : \ > + access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \ > + __get_user(x, __p) : \
Likewise.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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