From: Peter Zijlstra <peterz@infradead.org>
To: 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, aryabinin@virtuozzo.com,
glider@google.com, dvyukov@google.com
Subject: Re: [PATCH 5/6] objtool: Add UACCESS validation
Date: Wed, 27 Feb 2019 15:08:30 +0100 [thread overview]
Message-ID: <20190227140830.GP32494@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190225125232.191698923@infradead.org>
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.
---
>> arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x59: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x6a: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x7b: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x8f: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0xa3: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0xb4: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0xc5: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0xdc: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0xf0: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x101: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x112: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x123: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x134: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x145: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x156: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x167: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x177: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x192: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x1bc: call to __asan_store8_noabort() with UACCESS enabled
>> arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x1f2: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x212: call to __asan_store8_noabort() with UACCESS enabled
>> arch/x86/kernel/signal.o: warning: objtool: restore_sigcontext()+0x1d8: call to force_valid_ss.isra.0() with UACCESS enabled
>> arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x3f: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x50: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x61: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x75: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x89: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x9a: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0xab: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0xbc: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0xcd: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0xde: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0xef: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x100: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x111: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x122: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x133: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x143: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x157: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x173: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x18e: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x1a8: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x1c2: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x1ee: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: setup_sigcontext()+0x217: call to __asan_load8_noabort() with UACCESS enabled
>> arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x618: call to __asan_load8_noabort() with UACCESS enabled
>> arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x630: call to __asan_loadN_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x681: call to __asan_load8_noabort() with UACCESS enabled
>> arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x6a0: call to __asan_load4_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x6bd: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x7cb: call to __asan_load8_noabort() with UACCESS enabled
>> arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x6dd: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x6f0: call to __asan_store8_noabort() with UACCESS enabled
>> arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x707: call to __asan_store4_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x2c6: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x2e3: call to __asan_loadN_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x334: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x352: call to __asan_load4_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x374: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x49d: call to __asan_load8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x393: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x3aa: call to __asan_store8_noabort() with UACCESS enabled
arch/x86/kernel/signal.o: warning: objtool: do_signal()+0x3c1: call to __asan_store4_noabort() with UACCESS enabled
next prev parent reply other threads:[~2019-02-27 14:08 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 [this message]
2019-02-27 14:17 ` Andrey Ryabinin
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
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