From: Christoph Hellwig <hch@lst.de>
To: Miles Chen <miles.chen@mediatek.com>
Cc: linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org,
Christoph Hellwig <hch@lst.de>,
wsd_upstream@mediatek.com,
"David S . Miller" <davem@davemloft.net>
Subject: Re: [PATCH] net: untag pointer in sockptr_is_kernel
Date: Tue, 11 Aug 2020 13:15:51 +0200 [thread overview]
Message-ID: <20200811111551.GA3958@lst.de> (raw)
In-Reply-To: <20200811102704.17875-1-miles.chen@mediatek.com>
On Tue, Aug 11, 2020 at 06:27:04PM +0800, Miles Chen wrote:
> From: Miles Chen <miles.chen@mediatek.com>
>
> sockptr_is_kernel() uses (sockptr.kernel >= TASK_SIZE) to tell
> if the pointer is kernel space or user space. When user space uses
> the "top byte ignored" feature such as HWAsan, we must untag
> the pointer before checking against TASK_SIZE.
>
> sockptr_is_kernel() will view a tagged user pointer as a kernel pointer
> and use memcpy directly and causes a kernel crash.
Dave merged a patch from me to rever the optimized sockptr
implementation for now. If we bring it back we should fold in your
fix.
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WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Miles Chen <miles.chen@mediatek.com>
Cc: Christoph Hellwig <hch@lst.de>,
"David S . Miller" <davem@davemloft.net>,
linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org,
wsd_upstream@mediatek.com
Subject: Re: [PATCH] net: untag pointer in sockptr_is_kernel
Date: Tue, 11 Aug 2020 13:15:51 +0200 [thread overview]
Message-ID: <20200811111551.GA3958@lst.de> (raw)
In-Reply-To: <20200811102704.17875-1-miles.chen@mediatek.com>
On Tue, Aug 11, 2020 at 06:27:04PM +0800, Miles Chen wrote:
> From: Miles Chen <miles.chen@mediatek.com>
>
> sockptr_is_kernel() uses (sockptr.kernel >= TASK_SIZE) to tell
> if the pointer is kernel space or user space. When user space uses
> the "top byte ignored" feature such as HWAsan, we must untag
> the pointer before checking against TASK_SIZE.
>
> sockptr_is_kernel() will view a tagged user pointer as a kernel pointer
> and use memcpy directly and causes a kernel crash.
Dave merged a patch from me to rever the optimized sockptr
implementation for now. If we bring it back we should fold in your
fix.
next prev parent reply other threads:[~2020-08-11 11:16 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-11 10:27 [PATCH] net: untag pointer in sockptr_is_kernel Miles Chen
2020-08-11 11:15 ` Christoph Hellwig [this message]
2020-08-11 11:15 ` Christoph Hellwig
2020-08-11 11:44 ` David Laight
2020-08-11 11:44 ` David Laight
2020-08-12 9:15 ` Miles Chen
2020-08-12 9:15 ` Miles Chen
2020-08-12 9:48 ` David Laight
2020-08-12 9:48 ` David Laight
2020-08-11 12:24 ` kernel test robot
2020-08-11 12:24 ` kernel test robot
2020-08-11 12:24 ` kernel test robot
2020-08-11 12:28 ` kernel test robot
2020-08-11 12:28 ` kernel test robot
2020-08-11 12:28 ` kernel test robot
2020-08-12 9:17 ` Miles Chen
2020-08-12 9:17 ` Miles Chen
2020-08-12 9:17 ` Miles Chen
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