linux-kernel - Re: [PATCH 18/18] x86/traps: Use a new on_thread

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CALCETrXFhqtq+NzWOguwRpj0dHGxo1KHpwnCbr9PfFcC21feew@mail.gmail.com>
Date:   Wed, 1 Nov 2017 03:45:14 -0700
From:   Andy Lutomirski <luto@...nel.org>
To:     Borislav Petkov <bp@...e.de>
Cc:     Andy Lutomirski <luto@...nel.org>, X86 ML <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Brian Gerst <brgerst@...il.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 18/18] x86/traps: Use a new on_thread_stack() helper to
 clean up an assertion

I added a commit message :)

On Wed, Nov 1, 2017 at 3:31 AM, Borislav Petkov <bp@...e.de> wrote:
> On Thu, Oct 26, 2017 at 01:26:50AM -0700, Andy Lutomirski wrote:
>> Signed-off-by: Andy Lutomirski <luto@...nel.org>
>> ---
>>  arch/x86/include/asm/processor.h | 6 ++++++
>>  arch/x86/kernel/traps.c          | 3 +--
>>  2 files changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
>> index 562c575d8bc3..26fc33231cbd 100644
>> --- a/arch/x86/include/asm/processor.h
>> +++ b/arch/x86/include/asm/processor.h
>> @@ -541,6 +541,12 @@ static inline unsigned long current_top_of_stack(void)
>>  #endif
>>  }
>>
>> +static inline bool on_thread_stack(void)
>> +{
>> +     return (unsigned long)(current_top_of_stack() -
>> +                            current_stack_pointer) < THREAD_SIZE;
>> +}
>> +
>>  #ifdef CONFIG_PARAVIRT
>>  #include <asm/paravirt.h>
>>  #else
>> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
>> index 67db4f43309e..42a9c4458f5d 100644
>> --- a/arch/x86/kernel/traps.c
>> +++ b/arch/x86/kernel/traps.c
>> @@ -141,8 +141,7 @@ void ist_begin_non_atomic(struct pt_regs *regs)
>>        * will catch asm bugs and any attempt to use ist_preempt_enable
>>        * from double_fault.
>>        */
>> -     BUG_ON((unsigned long)(current_top_of_stack() -
>> -                            current_stack_pointer) >= THREAD_SIZE);
>> +     BUG_ON(!on_thread_stack());
>>
>>       preempt_enable_no_resched();
>>  }
>> --
>
> Having a commit message is always better. Other than that:
>
> Reviewed-by: Borislav Petkov <bp@...e.de>
>
> --
> Regards/Gruss,
>     Boris.
>
> SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
> --