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From: Christoph Hellwig <hch@infradead.org>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: Kees Cook <keescook@chromium.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Felipe Balbi <felipe.balbi@linux.intel.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-usb@vger.kernel.org, Christoph Hellwig <hch@infradead.org>
Subject: Re: [GIT PULL] USB/PHY driver patches for 4.17-rc1
Date: Thu, 5 Apr 2018 00:31:11 -0700	[thread overview]
Message-ID: <20180405073111.GA15981@infradead.org> (raw)
In-Reply-To: <2d80686d-529d-0238-b91c-3fb88bcf37d5@metafoo.de>

On Thu, Apr 05, 2018 at 09:19:28AM +0200, Lars-Peter Clausen wrote:
> On 04/05/2018 08:31 AM, Kees Cook wrote:
> > On Wed, Apr 4, 2018 at 3:31 AM, Greg KH <gregkh@linuxfoundation.org> wrote:
> >> Lars-Peter Clausen (2):
> >>       usb: gadget: ffs: Execute copy_to_user() with USER_DS set
> > 
> > https://git.kernel.org/linus/4058ebf33cb0be88ca516f968eda24ab7b6b93e4
> > 
> > Isn't there a better way to do this without the set_fs() usage? We've
> > been try to eliminate it in the kernel. I thought there was a safer
> > way to use iters now?
> 
> The problem is use_mm(). It needs to be accompanied with set_fs(DS_USER) to
> work reliably. This has simply been missing for this particular instance of
> use_mm().

To me it seems like use_mm() should do set_fs(USER_DS) and unuse_mm()
should do set_fs(KERNEL_DS) to get drivers outo of this mess.  I'll see
if I can come up with patches for the next merge window.

  reply	other threads:[~2018-04-05  7:31 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-04 10:31 [GIT PULL] USB/PHY driver patches for 4.17-rc1 Greg KH
2018-04-05  6:31 ` Kees Cook
2018-04-05  7:19   ` Lars-Peter Clausen
2018-04-05  7:31     ` Christoph Hellwig [this message]
2018-04-06  0:04       ` Al Viro

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