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From:   David Laight <David.Laight@ACULAB.COM>
To:     "'Kirill A. Shutemov'" <kirill.shutemov@linux.intel.com>,
        "kirill@shutemov.name" <kirill@shutemov.name>
CC:     "dave.hansen@intel.com" <dave.hansen@intel.com>,
        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
        "jejb@linux.ibm.com" <jejb@linux.ibm.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "lkp@intel.com" <lkp@intel.com>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
        "oe-kbuild-all@lists.linux.dev" <oe-kbuild-all@lists.linux.dev>,
        "x86@kernel.org" <x86@kernel.org>
Subject: RE: [PATCH 1/2] scsi: Fix get_user() in call sg_scsi_ioctl()
Thread-Topic: [PATCH 1/2] scsi: Fix get_user() in call sg_scsi_ioctl()
Thread-Index: AQHY+VSNJhar89N50E24WEBG2HeXiK5CJcRg
Date:   Wed, 16 Nov 2022 22:40:09 +0000
Message-ID: <9d59ec367e0445028775d304bcf64704@AcuMS.aculab.com>
References: <20221115155802.p3vjnk7eqqcyskt3@box.shutemov.name>
 <20221116004353.15052-1-kirill.shutemov@linux.intel.com>
 <20221116004353.15052-2-kirill.shutemov@linux.intel.com>
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From: Kirill A. Shutemov
> Sent: 16 November 2022 00:44
> 
> get_user() expects the pointer to be pointer-to-simple-variable type,
> but sic->data is array of 'unsigned char'. It violates get_user()
> contracts.
> 
> Cast it explicitly to 'unsigned char __user *'. It matches current
> behaviour.
> 
> This is preparation for fixing sparse warnings caused by Linear Address
> Masking patchset.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> ---
>  drivers/scsi/scsi_ioctl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/scsi_ioctl.c b/drivers/scsi/scsi_ioctl.c
> index 2d20da55fb64..72b3ab5137b8 100644
> --- a/drivers/scsi/scsi_ioctl.c
> +++ b/drivers/scsi/scsi_ioctl.c
> @@ -519,7 +519,7 @@ static int sg_scsi_ioctl(struct request_queue *q, fmode_t mode,
>  		return -EFAULT;
>  	if (in_len > PAGE_SIZE || out_len > PAGE_SIZE)
>  		return -EINVAL;
> -	if (get_user(opcode, sic->data))
> +	if (get_user(opcode, (unsigned char __user *)sic->data))

Using &sic->data[0] should work and is much nicer than the cast.

	David

>  		return -EFAULT;
> 
>  	bytes = max(in_len, out_len);
> --
> 2.38.0

-
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