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From: Christoph Hellwig <hch@infradead.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>,
	Sumit Saxena <sumit.saxena@broadcom.com>,
	Shivasharan S <shivasharan.srikanteshwara@broadcom.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	hch@infradead.org, stable@vger.kernel.org,
	Anand Lodnoor <anand.lodnoor@broadcom.com>,
	Chandrakanth Patil <chandrakanth.patil@broadcom.com>,
	Hannes Reinecke <hare@suse.de>,
	megaraidlinux.pdl@broadcom.com, linux-scsi@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] scsi: megaraid_sas: check user-provided offsets
Date: Sat, 12 Sep 2020 08:20:53 +0100	[thread overview]
Message-ID: <20200912072053.GB1945@infradead.org> (raw)
In-Reply-To: <20200908213715.3553098-2-arnd@arndb.de>

On Tue, Sep 08, 2020 at 11:36:22PM +0200, Arnd Bergmann wrote:
> It sounds unwise to let user space pass an unchecked 32-bit
> offset into a kernel structure in an ioctl. This is an unsigned
> variable, so checking the upper bound for the size of the structure
> it points into is sufficient to avoid data corruption, but as
> the pointer might also be unaligned, it has to be written carefully
> as well.
> 
> While I stumbled over this problem by reading the code, I did not
> continue checking the function for further problems like it.

Oh, yikes!

> 
> Cc: stable@vger.kernel.org

What about a Fixes tag instead?

>  	if (ioc->sense_len) {
> +		/* make sure the pointer is part of the frame */
> +		if (ioc->sense_off > (sizeof(union megasas_frame) - sizeof(__le64))) {

No need for the inner braces and please avoid over 80 char lines.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

  reply	other threads:[~2020-09-12  7:21 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-08 21:36 [PATCH 1/3] scsi: aacraid: improve compat_ioctl handlers Arnd Bergmann
2020-09-08 21:36 ` [PATCH 2/3] scsi: megaraid_sas: check user-provided offsets Arnd Bergmann
2020-09-12  7:20   ` Christoph Hellwig [this message]
2020-09-12 17:03     ` Arnd Bergmann
2020-12-31  0:15   ` Phil Oester
2021-01-03 16:26     ` Arnd Bergmann
2021-01-03 17:00       ` James Bottomley
2021-01-03 18:49         ` Arnd Bergmann
2021-01-03 20:12           ` James Bottomley
2021-01-04 17:48       ` Phil Oester
2021-01-04 22:24         ` Arnd Bergmann
2020-09-08 21:36 ` [PATCH 3/3] scsi: megaraid_sas: simplify compat_ioctl handling Arnd Bergmann
2020-09-12  7:47   ` Christoph Hellwig
2020-09-12 12:49     ` Arnd Bergmann
2020-09-13  6:50       ` compat_alloc_user_space removal, was " Christoph Hellwig
2020-09-13 11:46         ` Arnd Bergmann
2020-09-17 14:55           ` Arnd Bergmann
2020-09-17 14:57             ` Christoph Hellwig
2020-09-12  7:09 ` [PATCH 1/3] scsi: aacraid: improve compat_ioctl handlers Christoph Hellwig
2020-09-17 15:02   ` Arnd Bergmann

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