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From: James Bottomley <jejb@linux.vnet.ibm.com>
To: Greg KH <gregkh@linuxfoundation.org>,
	Dan Williams <dan.j.williams@intel.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arch@vger.kernel.org,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	linux-scsi <linux-scsi@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Netdev <netdev@vger.kernel.org>,
	qla2xxx-upstream@qlogic.com, Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Elena Reshetova <elena.reshetova@intel.com>,
	Alan Cox <alan@linux.intel.com>
Subject: Re: [PATCH 10/18] qla2xxx: prevent bounds-check bypass via speculative execution
Date: Fri, 12 Jan 2018 07:25:11 -0800	[thread overview]
Message-ID: <1515770711.3922.5.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <20180112072758.GD25517@kroah.com>

On Fri, 2018-01-12 at 08:27 +0100, Greg KH wrote:
> On Thu, Jan 11, 2018 at 02:15:12PM -0800, Dan Williams wrote:
> > 
> > On Sat, Jan 6, 2018 at 1:03 AM, Greg KH <gregkh@linuxfoundation.org
> > > wrote:
> > > 
> > > On Fri, Jan 05, 2018 at 05:10:48PM -0800, Dan Williams wrote:
> > > > 
> > > > Static analysis reports that 'handle' may be a user controlled
> > > > value that is used as a data dependency to read 'sp' from the
> > > > 'req->outstanding_cmds' array.  In order to avoid potential
> > > > leaks of kernel memory values, block speculative execution of
> > > > the instruction stream that could issue reads based on an
> > > > invalid value of 'sp'. In this case 'sp' is directly
> > > > dereferenced later in the function.
> > > 
> > > I'm pretty sure that 'handle' comes from the hardware, not from
> > > userspace, from what I can tell here.  If we want to start
> > > auditing __iomem data sources, great!  But that's a bigger task,
> > > and one I don't think we are ready to tackle...
> > 
> > I think it falls in the hygiene bucket of shutting off an array
> > index from a source that could be under attacker control. Should we
> > leave this one un-patched while we decide if we generally have a
> > problem with trusting completion 'tags' from hardware? My vote is
> > patch it for now.
> 
> Hah, if you are worried about "tags" from hardware, we have a lot
> more auditing to do, right? 

We'd also have a lot more to do: the assumption would have to be
malicious hardware and most hardware has access to fairly vital stuff
directly.  I really don't think we have to worry about side channel
attacks from hardware until the direct attack vector is closed.

James

  reply	other threads:[~2018-01-12 15:26 UTC|newest]

Thread overview: 161+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-06  1:09 [PATCH 00/18] prevent bounds-check bypass via speculative execution Dan Williams
2018-01-06  1:09 ` [PATCH 01/18] asm-generic/barrier: add generic nospec helpers Dan Williams
2018-01-06  2:55   ` Linus Torvalds
2018-01-06  5:23     ` Dan Williams
2018-01-06 17:08       ` Mark Rutland
2018-01-06  1:10 ` [PATCH 02/18] Documentation: document " Dan Williams
2018-01-08 16:29   ` Jonathan Corbet
2018-01-08 17:09     ` Mark Rutland
2018-01-08 21:19       ` Jonathan Corbet
2018-01-06  1:10 ` [PATCH 03/18] arm64: implement nospec_ptr() Dan Williams
2018-01-06  1:10 ` [PATCH 04/18] arm: " Dan Williams
2018-01-10  2:04   ` Laura Abbott
2018-01-10  7:40     ` Hanjun Guo
2018-01-10 17:24       ` Laura Abbott
2018-01-06  1:10 ` [PATCH 05/18] x86: implement nospec_barrier() Dan Williams
2018-01-06  1:10 ` [PATCH 06/18] x86, barrier: stop speculation for failed access_ok Dan Williams
2018-01-06  2:52   ` Linus Torvalds
2018-01-06  3:09     ` Linus Torvalds
2018-01-06 23:31       ` Dan Williams
2018-01-07  1:20         ` Linus Torvalds
2018-01-08 21:09           ` Dan Williams
2018-01-08 23:44             ` Linus Torvalds
2018-01-08 23:53               ` Dan Williams
2018-01-06  5:47     ` Dan Williams
2018-01-06 12:32     ` Alan Cox
2018-01-06 17:56       ` Linus Torvalds
2018-01-06 18:13       ` Alexei Starovoitov
2018-01-06 18:29         ` Dan Williams
2018-01-06 18:39           ` Alexei Starovoitov
2018-01-06 18:54             ` Dan Williams
2018-01-06 19:25               ` Alexei Starovoitov
2018-01-06 19:36                 ` Dan Williams
2018-01-06 19:41                 ` Thomas Gleixner
2018-01-08 10:02                   ` Andrea Arcangeli
2018-01-06 18:38         ` Alan Cox
2018-01-06 18:51           ` Alexei Starovoitov
2018-01-06 19:55             ` Alan Cox
2018-01-06 20:09               ` Alexei Starovoitov
2018-01-06 20:22                 ` Alan Cox
2018-01-06 21:17                   ` Alexei Starovoitov
2018-01-06 21:21                     ` Thomas Gleixner
2018-01-06 23:05                     ` Alan Cox
2018-01-07  3:38                       ` Alexei Starovoitov
2018-01-07  6:33                         ` Willy Tarreau
2018-01-07 19:47                           ` Linus Torvalds
2018-01-07 20:12                             ` Willy Tarreau
2018-01-07 20:17                               ` Linus Torvalds
2018-01-07 20:56                                 ` Thomas Gleixner
2018-01-08  2:23                                   ` David Miller
2018-01-08  7:38                                     ` Greg KH
2018-01-07 22:15                                 ` Willy Tarreau
2018-01-07 20:15                             ` Dan Williams
2018-01-08  2:24                               ` Alexei Starovoitov
2018-01-08  9:51                                 ` Peter Zijlstra
2018-01-08 18:21                                   ` Ingo Molnar
2018-01-08 12:00                             ` David Laight
2018-01-08 12:12                               ` Alan Cox
2018-01-08 12:33                                 ` David Laight
2018-01-07 10:08                         ` Thomas Gleixner
2018-01-08  2:09                           ` Alexei Starovoitov
2018-01-07 13:59                         ` Alan Cox
2018-01-08  2:57                           ` Alexei Starovoitov
2018-01-08  9:57                             ` Peter Zijlstra
2018-01-06 20:42           ` Willy Tarreau
2018-01-07  1:36             ` David Miller
2018-01-07 17:19               ` James Bottomley
2018-01-07 18:31                 ` Thomas Gleixner
2018-01-08  2:04                   ` David Miller
2018-01-07 19:24                 ` Alan Cox
2018-01-09 21:41     ` Josh Poimboeuf
2018-01-09 21:47       ` Dan Williams
2018-01-09 21:49         ` Josh Poimboeuf
2018-01-09 21:59           ` Dan Williams
2018-01-09 22:23             ` Josh Poimboeuf
2018-01-09 22:35               ` Dan Williams
2018-01-06  1:10 ` [PATCH 07/18] [media] uvcvideo: prevent bounds-check bypass via speculative execution Dan Williams
2018-01-06  9:09   ` Greg KH
2018-01-06  9:40     ` Greg KH
2018-01-06 17:41       ` Dan Williams
2018-01-07  9:09         ` Greg KH
2018-01-07 19:37           ` Dan Williams
2018-01-09  8:40       ` Laurent Pinchart
2018-01-09 10:04         ` Greg KH
2018-01-09 14:26           ` Laurent Pinchart
2018-01-09 14:47             ` Greg KH
2018-01-08 11:23   ` Laurent Pinchart
2018-01-09  2:11     ` Dan Williams
2018-01-06  1:10 ` [PATCH 08/18] carl9170: " Dan Williams
2018-01-06 10:01   ` Sergei Shtylyov
2018-01-06 14:23   ` Christian Lamparter
2018-01-06 15:06     ` Alan Cox
2018-01-06 16:38       ` Christian Lamparter
2018-01-06 16:34     ` Dan Williams
2018-01-06  1:10 ` [PATCH 09/18] p54: " Dan Williams
2018-01-06 10:01   ` Sergei Shtylyov
2018-01-06  1:10 ` [PATCH 10/18] qla2xxx: " Dan Williams
2018-01-06  9:03   ` Greg KH
2018-01-06  9:42     ` Greg KH
2018-01-11 22:15     ` Dan Williams
2018-01-12  7:27       ` Greg KH
2018-01-12 15:25         ` James Bottomley [this message]
2018-01-06  1:10 ` [PATCH 11/18] cw1200: " Dan Williams
2018-01-06  1:10 ` [PATCH 12/18] Thermal/int340x: " Dan Williams
2018-01-06  1:53   ` Srinivas Pandruvada
2018-01-06  1:57     ` Dan Williams
2018-01-06 17:24       ` Srinivas Pandruvada
2018-01-06 10:03   ` Sergei Shtylyov
2018-01-06  1:11 ` [PATCH 13/18] ipv6: " Dan Williams
2018-01-06 10:04   ` Sergei Shtylyov
2018-01-06 14:48   ` Stephen Hemminger
2018-01-06 18:05     ` Dan Williams
2018-01-06  1:11 ` [PATCH 14/18] ipv4: " Dan Williams
2018-01-06  9:00   ` Greg KH
2018-01-06  9:01   ` Greg KH
2018-01-06 12:23     ` Alan Cox
2018-01-06 15:14       ` Greg KH
2018-01-06 16:29         ` Dan Williams
2018-01-06 18:10           ` Dan Williams
2018-01-06 10:04   ` Sergei Shtylyov
2018-01-06  1:11 ` [PATCH 15/18] vfs, fdtable: " Dan Williams
2018-01-06 10:05   ` Sergei Shtylyov
2018-01-06  1:11 ` [PATCH 16/18] net: mpls: " Dan Williams
2018-01-06 10:06   ` Sergei Shtylyov
2018-01-09  3:11   ` Eric W. Biederman
2018-01-09  3:42     ` Dan Williams
2018-01-09  4:13       ` Linus Torvalds
2018-01-09  4:21         ` Linus Torvalds
2018-01-10  0:48         ` Dan Williams
2018-01-10  1:33           ` Dan Williams
2018-01-10  1:57           ` Alexei Starovoitov
2018-01-10  2:22             ` Dan Williams
2018-01-10  3:07               ` Alexei Starovoitov
2018-01-10  3:27           ` Linus Torvalds
2018-01-09 16:17       ` Eric W. Biederman
2018-01-09 18:01         ` Dan Williams
2018-01-10  0:54           ` Eric W. Biederman
2018-01-10  1:31             ` Dan Williams
2018-01-06  1:11 ` [PATCH 17/18] udf: " Dan Williams
2018-01-08 10:20   ` Jan Kara
2018-01-06  1:11 ` [PATCH 18/18] userns: " Dan Williams
2018-01-06  2:22 ` [PATCH 00/18] " Eric W. Biederman
2018-01-06  6:30   ` Dan Williams
2018-01-08 10:08     ` Peter Zijlstra
2018-01-08 11:14       ` Laurent Pinchart
2018-01-08 11:43       ` Alan Cox
2018-01-08 11:55         ` Peter Zijlstra
2018-01-08 18:33         ` Ingo Molnar
2018-01-08 16:20     ` Bart Van Assche
2018-01-06 18:56 ` Florian Fainelli
2018-01-06 18:59   ` Arjan van de Ven
2018-01-06 19:37 ` Dan Williams
2018-01-06 20:07   ` Dan Williams
2018-01-08  4:49 ` Bart Van Assche
2018-01-08 13:33   ` Arjan van de Ven
2018-01-09 19:34 ` Jiri Kosina
2018-01-09 19:44   ` Dan Williams
2018-01-09 20:55     ` Josh Poimboeuf
2018-01-11  9:54       ` Jiri Kosina
2018-01-11 15:58         ` Dan Williams
2018-01-11 16:34           ` Daniel Borkmann
2018-01-13 11:33 ` QingFeng Hao

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