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From: Christoph Hellwig <hch@lst.de>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Eric Dumazet <edumazet@google.com>,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org, bpf@vger.kernel.org,
	netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
	linux-sctp@vger.kernel.org, linux-hams@vger.kernel.org,
	linux-bluetooth@vger.kernel.org,
	bridge@lists.linux-foundation.org, linux-can@vger.kernel.org,
	dccp@vger.kernel.org, linux-decnet-user@lists.sourceforge.net,
	linux-wpan@vger.kernel.org, linux-s390@vger.kernel.org,
	mptcp@lists.01.org, lvs-devel@vger.kernel.org,
	rds-devel@oss.oracle.com, linux-afs@lists.infradead.org,
	tipc-discussion@lists.sourceforge.net, linux-x25@vger.kernel.org
Subject: Re: [PATCH 03/24] net: add a new sockptr_t type
Date: Wed, 22 Jul 2020 09:56:20 +0200	[thread overview]
Message-ID: <20200722075620.GA26554@lst.de> (raw)
In-Reply-To: <20200720175543.GF1292162@gmail.com>

On Mon, Jul 20, 2020 at 10:55:43AM -0700, Eric Biggers wrote:
> On Mon, Jul 20, 2020 at 07:43:22PM +0200, Christoph Hellwig wrote:
> > On Mon, Jul 20, 2020 at 09:37:48AM -0700, Eric Biggers wrote:
> > > How does this not introduce a massive security hole when
> > > CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE?
> > > 
> > > AFAICS, userspace can pass in a pointer >= TASK_SIZE,
> > > and this code makes it be treated as a kernel pointer.
> > 
> > Yeah, we'll need to validate that before initializing the pointer.
> > 
> > But thinking this a little further:  doesn't this mean any
> > set_fs(KERNEL_DS) that has other user pointers than the one it is
> > intended for has the same issue?  Pretty much all of these are gone
> > in mainline now, but in older stable kernels there might be some
> > interesting cases, especially in the compat ioctl handlers.
> 
> Yes.  I thought that eliminating that class of bug is one of the main
> motivations for your "remove set_fs" work.  See commit 128394eff343
> ("sg_write()/bsg_write() is not fit to be called under KERNEL_DS") for a case
> where this type of bug was fixed.
> 
> Are you aware of any specific cases that weren't already fixed?  If there are
> any, they need to be urgently fixed.

current mainline has almost no set_fs left, and setsockopt seems
pretty much safe.  But if we go back a long term stable release or two
I bet I'd find one or two.

  reply	other threads:[~2020-07-22  7:56 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-20 12:47 get rid of the address_space override in setsockopt Christoph Hellwig
2020-07-20 12:47 ` [PATCH 01/24] bpfilter: reject kernel addresses Christoph Hellwig
2020-07-20 12:47 ` [PATCH 02/24] bpfilter: fix up a sparse annotation Christoph Hellwig
2020-07-21  2:40   ` Luc Van Oostenryck
2020-07-21  5:23     ` Christoph Hellwig
2020-07-21  5:28       ` Al Viro
2020-07-20 12:47 ` [PATCH 03/24] net: add a new sockptr_t type Christoph Hellwig
2020-07-20 16:37   ` Eric Biggers
2020-07-20 17:43     ` Christoph Hellwig
2020-07-20 17:55       ` Eric Biggers
2020-07-22  7:56         ` Christoph Hellwig [this message]
2020-07-21  9:55     ` David Laight
2020-07-21 10:14   ` David Laight
2020-07-20 12:47 ` [PATCH 04/24] net: switch copy_bpf_fprog_from_user to sockptr_t Christoph Hellwig
2020-07-20 12:47 ` [PATCH 05/24] net: switch sock_setbindtodevice " Christoph Hellwig
2020-07-20 12:47 ` [PATCH 06/24] net: switch sock_set_timeout " Christoph Hellwig
2020-07-20 12:47 ` [PATCH 07/24] " Christoph Hellwig
2020-07-20 12:47 ` [PATCH 08/24] net/xfrm: switch xfrm_user_policy " Christoph Hellwig
2020-07-20 12:47 ` [PATCH 09/24] netfilter: remove the unused user argument to do_update_counters Christoph Hellwig
2020-07-20 12:47 ` [PATCH 10/24] netfilter: switch xt_copy_counters to sockptr_t Christoph Hellwig
2020-07-20 12:47 ` [PATCH 11/24] netfilter: switch nf_setsockopt " Christoph Hellwig
2020-07-20 12:47 ` [PATCH 12/24] bpfilter: switch bpfilter_ip_set_sockopt " Christoph Hellwig
2020-07-21  8:36   ` David Laight
2020-07-22  8:00     ` 'Christoph Hellwig'
2020-07-22  8:01       ` 'Christoph Hellwig'
2020-07-20 12:47 ` [PATCH 13/24] net/ipv4: switch ip_mroute_setsockopt " Christoph Hellwig
2020-07-20 12:47 ` [PATCH 14/24] net/ipv4: merge ip_options_get and ip_options_get_from_user Christoph Hellwig
2020-07-20 12:47 ` [PATCH 15/24] net/ipv4: switch do_ip_setsockopt to sockptr_t Christoph Hellwig
2020-07-20 12:47 ` [PATCH 16/24] net/ipv6: switch ip6_mroute_setsockopt " Christoph Hellwig
2020-07-20 12:47 ` [PATCH 17/24] net/ipv6: split up ipv6_flowlabel_opt Christoph Hellwig
2020-07-20 12:47 ` [PATCH 18/24] net/ipv6: switch ipv6_flowlabel_opt to sockptr_t Christoph Hellwig
2020-07-20 12:47 ` [PATCH 19/24] net/ipv6: factor out a ipv6_set_opt_hdr helper Christoph Hellwig
2020-07-20 12:47 ` [PATCH 20/24] net/ipv6: switch do_ipv6_setsockopt to sockptr_t Christoph Hellwig
2020-07-20 12:47 ` [PATCH 21/24] net/udp: switch udp_lib_setsockopt " Christoph Hellwig
2020-07-20 12:47 ` [PATCH 22/24] net/tcp: switch ->md5_parse " Christoph Hellwig
2020-07-20 12:47 ` [PATCH 23/24] net/tcp: switch do_tcp_setsockopt " Christoph Hellwig
2020-07-20 12:47 ` [PATCH 24/24] net: pass a sockptr_t into ->setsockopt Christoph Hellwig
2020-07-20 14:19   ` Stefan Schmidt
2020-07-20 23:20     ` David Miller
2020-07-22  8:26   ` [MPTCP] " Matthieu Baerts
2020-07-20 16:38 ` get rid of the address_space override in setsockopt Eric Biggers
2020-07-20 17:43   ` Christoph Hellwig
2020-07-20 20:47 ` Alexei Starovoitov
2020-07-22  7:56   ` Christoph Hellwig
2020-07-22 17:09     ` Alexei Starovoitov
2020-07-21  9:38 ` David Laight
2020-07-22  8:06   ` 'Christoph Hellwig'
2020-07-22  8:21     ` David Laight
2020-07-21 10:26 ` David Laight
2020-07-22  8:07   ` 'Christoph Hellwig'

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