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Message-ID: <CAGXu5j+uUH9fRbFSkVGeAc1Z6+oLHPLLFFvkU6KDC6nuDX-8Lw@mail.gmail.com>
Date: Wed, 26 Oct 2016 13:51:05 -0700
From: Kees Cook <keescook@...omium.org>
To: "Reshetova, Elena" <elena.reshetova@...el.com>
Cc: David Windsor <dwindsor@...il.com>, AKASHI Takahiro <takahiro.akashi@...aro.org>,
"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>,
Hans Liljestrand <ishkamiel@...il.com>
Subject: Re: [RFC v2 PATCH 12/13] x86: implementation for HARDENED_ATOMIC
On Wed, Oct 26, 2016 at 4:15 AM, Reshetova, Elena
<elena.reshetova@...el.com> wrote:
>>> +static __always_inline int __atomic_add_unless_wrap(atomic_wrap_t *v,
>>> + int a, int u)
>>> +{
>>> + int c, old, new;
>>> + c = atomic_read_wrap(v);
>>> + for (;;) {
>>> + if (unlikely(c == (u)))
>>> + break;
>>> +
>>> + asm volatile("addl %2,%0\n"
>>> +
>>> +#ifdef CONFIG_HARDENED_ATOMIC
>>> + "jno 0f\n"
>>> + "subl %2,%0\n"
>>> + "int $4\n0:\n"
>>> + _ASM_EXTABLE(0b, 0b)
>>> +#endif
>>
>> Is this a mistake? We don't need a check here.
>
>>Yes, this appears to be a mistake.
>
> Clear copy paste mistake. Fixed now. Thanks again!
What was the mistake here?
-Kees
--
Kees Cook
Nexus Security
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