linux-kernel - Re: [GIT PULL] gcc-plugins updates for v4.13-rc1

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Message-ID: <CAGXu5j+Jf8aPMHxsK3XMCk0TCn-5-uSkAZvUcSnFrLsPOp-aRQ@mail.gmail.com>
Date:   Wed, 5 Jul 2017 14:52:34 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Jean Delvare <jdelvare@...e.de>
Subject: Re: [GIT PULL] gcc-plugins updates for v4.13-rc1

On Wed, Jul 5, 2017 at 2:48 PM, Arnd Bergmann <arnd@...db.de> wrote:
> On Wed, Jul 5, 2017 at 11:35 PM, Linus Torvalds
> <torvalds@...ux-foundation.org> wrote:
>
>> So the issue I think would be good to fix is perhaps best explained by
>> pseudo-code
>>
>>   int testfn(struct somestruct __user *p)
>>   {
>>         struct somestruct a;
>>
>>         initialize_struct(&a);
>>         if (copy_to_user(p, &a, sizeof(a)))
>>                 return -EFAULT;
>>         return 0;
>>   }
>>
>> which is obviously made-up code, but is not actually entirely unrealistic.
>
> This particular example should be handled by
> scripts/gcc-plugins/structleak_plugin.c, right?

Only if struct somestruct _contains_ a __user pointer. I would love to
see this logic expanded, of course. :)

-Kees

-- 
Kees Cook
Pixel Security