From: Scott Bauer <scott.bauer@intel.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: "keith.busch@intel.com" <keith.busch@intel.com>,
"arnd@arndb.de" <arnd@arndb.de>,
"hch@infradead.org" <hch@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"axboe@fb.com" <axboe@fb.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"jonathan.derrick@intel.com" <jonathan.derrick@intel.com>
Subject: Re: Sed-opal fixups
Date: Thu, 9 Feb 2017 10:45:27 -0700 [thread overview]
Message-ID: <20170209174526.GA5200@sbauer-Z170X-UD5> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6DB0281B85@AcuExch.aculab.com>
On Thu, Feb 09, 2017 at 05:43:20PM +0000, David Laight wrote:
> From: Scott Bauer
> > Sent: 09 February 2017 17:20
> > It may be too late to change anyhting in the uapi header. When we
> > switched over to using IOC_SIZE I found a bug where I had switched
> > up a structure in one of the series from v4 to v5 but never changed
> > the structure in the IOW. The structure that was in there was to small
> > so when we kzalloc on it we don't request enough space. It worked before
> > because we were using the cmd strictly as a command #, not using the IOC
> > and friends.
> >
> > If it's too late to modify that IOW, I can work around it by reallocing
> > on the correct size for that command only. I verified the rest of the
> > commands and the structures are the same.
> >
> > Let me know what you think, please.
>
> Maybe define IOC_OPAL_ACTIVATE_LSP_OLD to the incorrect value and
> IOC_OPAL_ACTIVATE_LSP to the correct one.
> But that relies on any users specifying the correct structure.
> I wouldn't guarantee that.
I think I'm the only userspace user right now, this went in on monday,
so I can can change my tooling easily. I just wasnt sure if there was a
set time where the user ABI cannot be changed.
>
> At the top of the driver's ioctl path add:
> if (cmd == IOC_OPAL_ACTIVATE_LSP_OLD) cmd = IOC_OPAL_ACTIVATE_LSP;
>
I think it would have to be the other way around the correct sized one would
be IOC_OPAL_ACTIAVE_LSP_NEW so the check would be:
if (cmd == IOC_OPAL_ACTIVATE_LSP) cmd = IOC_OPAL_ACTIVATE_LSP_NEW. If we're
allowed to change it (the bad sized one) from LSP to LSP_OLD then we should
just change the structure. If we have to leave it we need to introduce a _NEW
with the correct size.
> For some code I added a userspace wrapper on ioctl() to check the
> size of the supplied arg matched that required by the 'cmd'.
> I've also done the same in the kernel.
> (all as compile time checks).
>
> David
>
>
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next prev parent reply other threads:[~2017-02-09 17:45 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-09 17:19 Sed-opal fixups Scott Bauer
2017-02-09 17:20 ` [PATCH V3 1/2] uapi: sed-opal fix IOW for activate lsp to use correct struct Scott Bauer
2017-02-09 17:20 ` [PATCH V3 2/2] Move stack parameters for sed_ioctl to prevent oversized stack with CONFIG_KASAN Scott Bauer
2017-02-09 19:51 ` Rafael Antognolli
2017-02-10 7:45 ` Johannes Thumshirn
2017-02-10 10:28 ` David Laight
2017-02-10 11:00 ` Arnd Bergmann
2017-02-10 8:01 ` Arnd Bergmann
2017-02-10 15:57 ` Scott Bauer
2017-02-09 17:43 ` Sed-opal fixups David Laight
2017-02-09 17:45 ` Scott Bauer [this message]
2017-02-09 18:24 ` Jens Axboe
2017-02-09 20:01 ` Scott Bauer
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