diff mbox series

[1/2] scsi: Fix get_user() in call sg_scsi_ioctl()

Message ID 20221116004353.15052-2-kirill.shutemov@linux.intel.com
State New
Headers
Series x86/mm: Fix sparse warning due to LAM patchset |

Commit Message

Kirill A. Shutemov Nov. 16, 2022, 12:43 a.m. UTC 
  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(-)

Comments

Dave Hansen Nov. 16, 2022, 12:48 a.m. UTC | #1 
On 11/15/22 16:43, Kirill A. Shutemov wrote:
> 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.

What's the side-effect if this isn't applied?  Is it worse than sparse
warnings?
Kirill A. Shutemov Nov. 16, 2022, 12:55 a.m. UTC | #2 
On Tue, Nov 15, 2022 at 04:48:40PM -0800, Dave Hansen wrote:
> On 11/15/22 16:43, Kirill A. Shutemov wrote:
> > 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.
> 
> What's the side-effect if this isn't applied?  Is it worse than sparse
> warnings?

Build will fail if 2/2 applied without this one:

arch/x86/include/asm/uaccess.h:46:9: error: cast specifies array type
David Laight Nov. 16, 2022, 10:40 p.m. UTC | #3 
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

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
Kirill A. Shutemov Nov. 17, 2022, 12:03 a.m. UTC | #4 
On Wed, Nov 16, 2022 at 10:40:09PM +0000, David Laight wrote:
> 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.

Okay. Fair enough. Adjusted patch is below.

From 86baed963c9295c067940479ab0f844c3644e1c9 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Wed, 16 Nov 2022 03:22:28 +0300
Subject: [PATCHv2 1/2] scsi: Fix get_user() in call sg_scsi_ioctl()

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.

Explicitly take pointer to the first element of the array. 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..fdd47565a311 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, &sic->data[0]))
 		return -EFAULT;
 
 	bytes = max(in_len, out_len);
diff mbox series

Patch

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