From: Jason Gunthorpe <jgg@ziepe.ca>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Parav Pandit <parav@mellanox.com>,
netdev@vger.kernel.org, Leon Romanovsky <leon@kernel.org>,
Eli Cohen <eli@mellanox.com>, Doug Ledford <dledford@redhat.com>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
"kernel-janitors@vger.kernel.org"
<kernel-janitors@vger.kernel.org>
Subject: Re: [PATCH] IB/mlx5: add checking for "vf" from do_setvfinfo()
Date: Wed, 24 Apr 2019 11:24:26 -0300 [thread overview]
Message-ID: <20190424142426.GH16061@ziepe.ca> (raw)
In-Reply-To: <20190424140820.GB14798@kadam>
On Wed, Apr 24, 2019 at 05:08:20PM +0300, Dan Carpenter wrote:
> I think I'm just going to ask netdev for an opinion on this. It could
> be that we're just reading the code wrong...
I don't think you are reading it wrong.
Allowing the compiler to implicitly cast a user controlled u32 to an
int is simply wrong in all cases, IMHO.
If the value was intended to be signed from the user it should have
been a s32. Allowing an unsigned value to become interpreted as
negative so often leads to security bugs.
IMHO it would be a good thing for smatch to warn on the general case
of implicit casting of user controlled data to a smaller range
type. Particularly it can do a bounds analysis to show the control
flow hasn't somehow restricted the bounds to be compatible.
I've seen more that a few real world security bugs that are caused by
wrong use of 'int' like this :(
Jason
next prev parent reply other threads:[~2019-04-24 14:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190412175504.GA20857@kadam>
[not found] ` <VI1PR0501MB22714D465D6CD60511FDFFD5D1280@VI1PR0501MB2271.eurprd05.prod.outlook.com>
[not found] ` <20190415094610.GO6095@kadam>
[not found] ` <VI1PR0501MB22713CCB1141529CCB6934B1D12B0@VI1PR0501MB2271.eurprd05.prod.outlook.com>
[not found] ` <20190416082112.GA27670@kadam>
[not found] ` <AM4PR0501MB22609E4C9D126A096DD7F614D1240@AM4PR0501MB2260.eurprd05.prod.outlook.com>
[not found] ` <20190420095102.GA14798@kadam>
[not found] ` <VI1PR0501MB22713B232B3CF42B849F959BD1220@VI1PR0501MB2271.eurprd05.prod.outlook.com>
[not found] ` <20190423154943.GC14820@kadam>
[not found] ` <AM4PR0501MB2260ADC1DA37E87D01979969D1230@AM4PR0501MB2260.eurprd05.prod.outlook.com>
2019-04-24 14:08 ` [PATCH] IB/mlx5: add checking for "vf" from do_setvfinfo() Dan Carpenter
2019-04-24 14:24 ` Jason Gunthorpe [this message]
2019-04-24 22:12 ` Parav Pandit
2019-04-25 0:36 ` Jakub Kicinski
2019-04-25 6:15 ` Parav Pandit
2019-09-24 9:21 ` Dan Carpenter
2019-09-25 17:14 ` Parav Pandit
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