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From: yalin wang <yalin.wang2010@gmail.com>
To: Borislav Petkov <bp@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	mingo@redhat.com, hpa@zytor.com, x86@kernel.org,
	open list <linux-kernel@vger.kernel.org>,
	Will Deacon <will.deacon@arm.com>
Subject: Re: [x86] copy_from{to}_user question
Date: Mon, 17 Aug 2015 11:27:01 +0800	[thread overview]
Message-ID: <6ABF6137-251E-47EF-B824-AC77C9C9AB24@gmail.com> (raw)
In-Reply-To: <20150813164302.GA15881@nazgul.tnic>


> On Aug 14, 2015, at 00:43, Borislav Petkov <bp@suse.de> wrote:
> 
> On Thu, Aug 13, 2015 at 06:04:54PM +0800, yalin wang wrote:
>> we store type into one fix register, for example r12 ,
>> then in fix up code, we can know the exception is caused by copy_from
>> copy_to or copy_in user function by check r12 value(0 , 1 ,2 value), then if 
>> it is copy_from, we only allow read fault, if the exception is write fault, panic() .
>> 
>> the same rules also apply to copy_to / copy_in function .
>> 
>> is it possible to change it like this ?
> 
> ... and we'll do all that jumping through hoops to fix what actual,
> real-life problem exactly?
i just want the x86 copy_from{to,in}_user() function have 
the same behaviour as other platforms.
and can disclose potential BUGs in kernel, if do like this.

Thanks.


  reply	other threads:[~2015-08-17  3:27 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-12  9:01 [x86] copy_from{to}_user question yalin wang
2015-08-12 10:07 ` Borislav Petkov
2015-08-13 10:04   ` yalin wang
2015-08-13 16:43     ` Borislav Petkov
2015-08-17  3:27       ` yalin wang [this message]
2015-08-17  4:16         ` Borislav Petkov
2015-08-20  8:58           ` yalin wang
2015-08-20 18:22           ` H. Peter Anvin
2015-08-21  4:35             ` Borislav Petkov
2015-08-21 21:06               ` H. Peter Anvin
2015-08-22  9:05                 ` Borislav Petkov
2015-08-24  7:52                   ` yalin wang
2015-08-24 12:05                     ` Jeff Epler

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