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Date: Sat, 26 Feb 2011 13:57:31 +0100
From: Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH 3/5] exec: unify compat_do_execve() code
Message-ID: <20110226125731.GA5315@redhat.com>
References: <20101130200129.GG11905@redhat.com> <compat-not-unlikely@mdm.bga.com> <20101201182747.GB6143@redhat.com> <20110225175202.GA19059@redhat.com> <20110225175314.GD19059@redhat.com> <AANLkTik8epq5cx8n=k6ocMUfbg9kkUAZ8KL7ZiG4UuoU@mail.gmail.com> <20110226123731.GC4416@redhat.com>
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To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, pageexec@freemail.hu, Solar Designer <solar@openwall.com>, Eugene Teo <eteo@redhat.com>, Brad Spengler <spender@grsecurity.net>, Roland McGrath <roland@redhat.com>, Milton Miller <miltonm@bga.com>

On 02/26, Oleg Nesterov wrote:
>
> Once again, to me "void __user*" looks better (just simpler). In this
> case get_arg_ptr() becomes (without const/__user for the clarity)
>
> 	void *get_arg_ptr(void **argv, int argc, bool compat)
> 	{
> 		char *ptr;
>
> 	#ifdef CONFIG_COMPAT
> 		if (unlikely(compat)) {
> 			compat_uptr_t *a = argv;
> 			compat_uptr_t p;
>
> 			if (get_user(p, a + argc))
> 				return ERR_PTR(-EFAULT);
>
> 			return compat_ptr(p);
> 		}
> 	#endif
>
> 		if (get_user(ptr, argv + argc))
> 			return ERR_PTR(-EFAULT);
>
> 		return ptr;
> 	}
>
> Otherwise, get_arg_ptr() should return conditional_user_ptr_t as well,

No, this is not true, I am stupid.

Still,

> this looks like the unnecessary complication to me, but of course this
> is subjective.
>
> So, what do you think?

Yes, please.

Oleg.

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