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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Christoph Hellwig <hch@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Network Development <netdev@vger.kernel.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arch@vger.kernel.org, Andi Kleen <ak@linux.intel.com>,
	Kees Cook <keescook@chromium.org>,
	kernel-hardening@lists.openwall.com,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alan Cox <alan@linux.intel.com>,
	David Miller <davem@davemloft.net>
Subject: Re: [RFC][PATCH] get rid of the use of set_fs() (by way of kernel_recvmsg()) in sunrpc
Date: Thu, 18 Jan 2018 17:10:20 +0000	[thread overview]
Message-ID: <20180118171020.GA13338@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20180118162957.GA16649@infradead.org>

On Thu, Jan 18, 2018 at 08:29:57AM -0800, Christoph Hellwig wrote:
> > 	We could turn ->msg_control/->msg_controllen into another
> > iov_iter, but seeing that we never do scatter-gather for those
> > IMO that would be a massive overkill.  A flag controlling whether
> > ->msg_control is kernel or userland pointer would do, especially
> > since we already have a flag for "do we want a native or compat
> > layout for cmsg" in there.
> 
> While your current hack seems like a nice short term improvement
> I think we need an iov_iter or iov_iter-light there in the long run.

For one caller in the entire history of the kernel?

> Same for ioctl so that we can pass properly typed kernel or user
> buffers through without all these set_fs hacks.

Umm...  Most of the PITA with ioctls is due to compat ones being
reformatted for native and fed under set_fs().  I actually have
a series dealing with most of such places for net ioctls.  Sure,
there's also ioctl_by_bdev(), but for those we might be better
off exposing the things like ->get_last_session() and its ilk to
filesystems that want to deal with cdroms...

It's kernel_setsockopt() that is the real PITA...

  parent reply	other threads:[~2018-01-18 17:10 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-13 18:17 [PATCH v3 0/9] core, x86: prevent bounds-check bypass via speculative execution Dan Williams
2018-01-13 18:17 ` Dan Williams
2018-01-13 18:17 ` [PATCH v3 1/9] Documentation: document array_ptr Dan Williams
2018-01-13 18:17   ` Dan Williams
2018-01-13 18:17 ` [PATCH v3 2/9] arm64: implement ifence_array_ptr() Dan Williams
2018-01-13 18:17 ` [PATCH v3 3/9] arm: " Dan Williams
2018-01-13 18:17   ` Dan Williams
2018-01-13 18:17 ` [PATCH v3 4/9] x86: implement ifence() Dan Williams
2018-01-13 18:17   ` Dan Williams
2018-01-13 18:17 ` [PATCH v3 5/9] x86: implement ifence_array_ptr() and array_ptr_mask() Dan Williams
2018-01-13 18:17   ` Dan Williams
2018-01-13 18:17 ` [PATCH v3 6/9] asm/nospec: mask speculative execution flows Dan Williams
2018-01-13 18:17   ` Dan Williams
2018-01-13 18:18 ` [PATCH v3 7/9] x86: introduce __uaccess_begin_nospec and ASM_IFENCE Dan Williams
2018-01-13 18:18   ` Dan Williams
2018-01-13 18:18 ` [PATCH v3 8/9] x86: use __uaccess_begin_nospec and ASM_IFENCE in get_user paths Dan Williams
2018-01-13 18:18   ` Dan Williams
2018-01-13 19:05   ` Linus Torvalds
2018-01-13 19:33     ` Linus Torvalds
2018-01-13 20:22       ` Eric W. Biederman
2018-01-13 20:22         ` Eric W. Biederman
2018-01-16 22:23       ` Dan Williams
2018-01-16 22:23         ` Dan Williams
     [not found]         ` <CA+55aFxAFG5czVmCyhYMyHmXLNJ7pcXxWzusjZvLRh_qTGHj6Q@mail.gmail.com>
2018-01-16 22:41           ` Linus Torvalds
2018-01-17 14:17             ` Alan Cox
2018-01-17 18:52               ` Al Viro
2018-01-17 18:52                 ` Al Viro
2018-01-17 19:54                 ` Dan Williams
2018-01-17 19:54                   ` Dan Williams
2018-01-17 20:05                   ` Al Viro
2018-01-17 20:14                     ` Dan Williams
2018-01-18  3:06                 ` [RFC][PATCH] get rid of the use of set_fs() (by way of kernel_recvmsg()) in sunrpc Al Viro
2018-01-18  3:06                   ` Al Viro
2018-01-18  3:16                   ` Linus Torvalds
2018-01-18  3:16                     ` Linus Torvalds
2018-01-18  4:43                     ` Al Viro
2018-01-18 16:29                       ` Christoph Hellwig
2018-01-18 16:29                         ` Christoph Hellwig
2018-01-18 17:10                         ` Al Viro [this message]
2018-01-18 19:31                       ` Al Viro
2018-01-18 20:33                         ` Al Viro
2018-01-19  3:27                         ` Al Viro
2018-01-19  3:27                           ` Al Viro
2018-01-17 19:26               ` [PATCH v3 8/9] x86: use __uaccess_begin_nospec and ASM_IFENCE in get_user paths Linus Torvalds
2018-01-17 20:01                 ` Eric Dumazet
2018-01-17 20:01                   ` Eric Dumazet
2018-01-18 16:38                 ` Christoph Hellwig
2018-01-18 16:49                   ` Linus Torvalds
2018-01-18 16:49                     ` Linus Torvalds
2018-01-18 18:12                     ` Al Viro
2018-01-17  4:30         ` Dan Williams
2018-01-17  6:28           ` Al Viro
2018-01-17  6:28             ` Al Viro
2018-01-17  6:50             ` Dan Williams
2018-01-17  6:50               ` Dan Williams
2018-01-17 10:07               ` David Laight
2018-01-17 10:07                 ` David Laight
2018-01-17 18:12               ` Dan Williams
2018-01-17 19:16           ` Linus Torvalds
2018-01-17 19:16             ` Linus Torvalds
2018-01-13 18:18 ` [PATCH v3 9/9] vfs, fdtable: prevent bounds-check bypass via speculative execution Dan Williams
2018-01-13 18:18   ` Dan Williams

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