From: Andrey Ryabinin <aryabinin@virtuozzo.com>
To: Peter Zijlstra <peterz@infradead.org>,
torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com,
julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net,
mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com,
valentin.schneider@arm.com, brgerst@gmail.com,
jpoimboe@redhat.com, luto@kernel.org, bp@alien8.de,
dvlasenk@redhat.com
Cc: linux-kernel@vger.kernel.org, glider@google.com, dvyukov@google.com
Subject: Re: [PATCH 5/6] objtool: Add UACCESS validation
Date: Wed, 27 Feb 2019 17:17:58 +0300 [thread overview]
Message-ID: <19b35cb1-9527-2e15-6deb-9ce7c1ef1d66@virtuozzo.com> (raw)
In-Reply-To: <20190227140830.GP32494@hirez.programming.kicks-ass.net>
On 2/27/19 5:08 PM, Peter Zijlstra wrote:
> On Mon, Feb 25, 2019 at 01:43:35PM +0100, Peter Zijlstra wrote:
>> It is important that UACCESS regions are as small as possible;
>> furthermore the UACCESS state is not scheduled, so doing anything that
>> might directly call into the scheduler will cause random code to be
>> ran with UACCESS enabled.
>>
>> Teach objtool too track UACCESS state and warn about any CALL made
>> while UACCESS is enabled. This very much includes the __fentry__()
>> tracing calls and __preempt_schedule() calls.
>>
>> Note that exceptions _do_ save/restore the UACCESS state, and therefore
>> they can drive preemption. This also means that all exception handlers
>> must have an otherwise dedundant UACCESS disable instruction;
>> therefore ignore this warning for !STT_FUNC code (exception handlers
>> are not normal functions).
>>
>> It also provides a UACCESS_SAFE() annotation which allows explicit
>> annotation. This is meant to be used for future things like:
>> unsafe_copy_{to,from}_user().
>>
>> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>
> So KASAN is wildly unhappy..
>
> I can't actually find any definitions of those functions, so I can't
> very well mark the safe, even if we wanted to.
>
They are macro-generated. Use 'git grep DEFINE_ASAN'
> ---
>
>>> arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x59: call to __asan_store8_noabort() with UACCESS enabled
next prev parent reply other threads:[~2019-02-27 14:17 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-25 12:43 [PATCH 0/6] objtool: UACCESS validation Peter Zijlstra
2019-02-25 12:43 ` [PATCH 1/6] x86/uaccess: Dont evaluate argument inside AC region Peter Zijlstra
2019-02-25 15:43 ` Andy Lutomirski
2019-02-25 16:02 ` Peter Zijlstra
2019-02-25 16:36 ` Borislav Petkov
2019-02-25 16:50 ` Andy Lutomirski
2019-02-25 19:09 ` Linus Torvalds
2019-02-25 19:18 ` Borislav Petkov
2019-02-25 18:10 ` [tip:x86/urgent] x86/uaccess: Don't leak the AC flag into __put_user() value evaluation tip-bot for Andy Lutomirski
2019-02-25 19:46 ` tip-bot for Andy Lutomirski
2019-02-25 12:43 ` [PATCH 2/6] x86/ia32: Fix ia32_restore_sigcontext AC leak Peter Zijlstra
2019-02-25 15:41 ` Andy Lutomirski
2019-02-25 16:10 ` Peter Zijlstra
2019-02-25 16:29 ` Andy Lutomirski
2019-02-25 16:37 ` Peter Zijlstra
2019-02-25 16:41 ` Peter Zijlstra
2019-02-25 16:49 ` Andy Lutomirski
2019-02-25 12:43 ` [PATCH 3/6] objtool: Set insn->func for alternatives Peter Zijlstra
2019-02-25 12:43 ` [PATCH 4/6] objtool: Replace STACK_FRAME_NON_STANDARD annotation Peter Zijlstra
2019-02-25 16:11 ` Josh Poimboeuf
2019-02-25 16:17 ` Peter Zijlstra
2019-02-25 16:23 ` Josh Poimboeuf
2019-02-27 12:20 ` Peter Zijlstra
2019-02-28 0:30 ` Andy Lutomirski
2019-02-25 12:43 ` [PATCH 5/6] objtool: Add UACCESS validation Peter Zijlstra
2019-02-25 15:53 ` Andy Lutomirski
2019-02-25 16:12 ` Peter Zijlstra
2019-02-25 17:15 ` Peter Zijlstra
2019-02-25 17:34 ` Linus Torvalds
2019-02-25 17:38 ` Josh Poimboeuf
2019-02-27 14:08 ` Peter Zijlstra
2019-02-27 14:17 ` Andrey Ryabinin [this message]
2019-02-27 14:26 ` Peter Zijlstra
2019-02-27 14:33 ` Peter Zijlstra
2019-02-27 15:40 ` Dmitry Vyukov
2019-02-27 17:28 ` Peter Zijlstra
2019-02-28 9:40 ` Peter Zijlstra
2019-02-28 9:59 ` Dmitry Vyukov
2019-02-28 10:05 ` Dmitry Vyukov
2019-02-28 10:52 ` Peter Zijlstra
2019-02-27 16:18 ` Linus Torvalds
2019-02-27 17:30 ` Peter Zijlstra
2019-02-27 17:36 ` Linus Torvalds
2019-02-25 12:43 ` [PATCH 6/6] objtool: Add Direction Flag validation Peter Zijlstra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=19b35cb1-9527-2e15-6deb-9ce7c1ef1d66@virtuozzo.com \
--to=aryabinin@virtuozzo.com \
--cc=bp@alien8.de \
--cc=brgerst@gmail.com \
--cc=catalin.marinas@arm.com \
--cc=dvlasenk@redhat.com \
--cc=dvyukov@google.com \
--cc=glider@google.com \
--cc=hpa@zytor.com \
--cc=james.morse@arm.com \
--cc=jpoimboe@redhat.com \
--cc=julien.thierry@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=luto@kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=valentin.schneider@arm.com \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).