From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Jann Horn <jannh@google.com>
Cc: Andy Lutomirski <luto@kernel.org>,
the arch/x86 maintainers <x86@kernel.org>,
kernel list <linux-kernel@vger.kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
kasan-dev@googlegroups.com,
Alexander Potapenko <glider@google.com>,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH] x86/entry/64: wipe KASAN stack shadow in rewind_stack_do_exit()
Date: Tue, 28 Aug 2018 14:33:48 +0300 [thread overview]
Message-ID: <daba9c5b-b5c6-beaa-ca96-81cf6af760b9@virtuozzo.com> (raw)
In-Reply-To: <CAG48ez1zYqx8-1We3JkDBmYREksUMoUe7VBeAOv2JH98gVWcKw@mail.gmail.com>
On 08/28/2018 01:38 PM, Jann Horn wrote:
>>
>>
>> Why this has to be done in the rewind_stack_do_exit()?
>> Are there any problems with calling the kasan_unpoison_task_stack(current) from oops_end(), before the rewind_stack_do_exit()?
>
> Ooh, good point! I didn't see that KASAN instrumentation is disabled
> for dumpstack.c.
It doesn't really matter. This would work with instrumented oops_end() as well.
kasan_unpoison_task_stack() will unpoison everything including oops_end's stack.
It would be also ok if kasan_unpoison_task_stack() instrumented, or calling any number of instrumented functions
in between kasan_unpoison_task_stack() and rewind_stack_do_exit(). As long as we return from these functions before
the rewind_stack_do_exit(), the stack will be unpoisoned on return.
next prev parent reply other threads:[~2018-08-28 11:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-24 23:58 Jann Horn
2018-08-25 0:13 ` Dmitry Vyukov
2018-08-28 9:04 ` Andrey Ryabinin
2018-08-28 10:38 ` Jann Horn
2018-08-28 11:33 ` Andrey Ryabinin [this message]
2018-08-28 12:53 ` Jann Horn
2018-08-28 19:57 ` Andy Lutomirski
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