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* [PATCH] compat_ioctl: fix reimplemented SG_IO handling causing -EINVAL from sg_io()
@ 2019-09-18 15:34 Steffen Maier
  2019-10-09 16:01 ` Arnd Bergmann
  0 siblings, 1 reply; 2+ messages in thread
From: Steffen Maier @ 2019-09-18 15:34 UTC (permalink / raw)
  To: Arnd Bergmann, James E . J . Bottomley, Martin K . Petersen,
	Doug Gilbert
  Cc: linux-scsi, linux-s390, Benjamin Block, Heiko Carstens,
	Vasily Gorbik, Steffen Maier, linux-kernel, Jens Axboe, viro,
	linux-fsdevel, Chaitanya Kulkarni, Thomas Gleixner,
	Mauro Carvalho Chehab, Omar Sandoval, linux-block, linux-next,
	Mark Brown, dm-devel

scsi_cmd_ioctl() had hdr as on stack auto variable and called
copy_{from,to}_user with the address operator &hdr and sizeof(hdr).

After the refactoring, {get,put}_sg_io_hdr() takes a pointer &hdr.
So the copy_{from,to}_user within the new helper functions should
just take the given pointer argument hdr and sizeof(*hdr).

I saw -EINVAL from sg_io() done by /usr/lib/udev/scsi_id which could
in turn no longer whitelist SCSI disks for devicemapper multipath.

Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Fixes: 4f45155c29fd ("compat_ioctl: reimplement SG_IO handling")
---

Arnd, I'm not sure about the sizeof(hdr32) change in the compat part in
put_sg_io_hdr().

This is for next, probably via Arnd's y2038/y2038,
and it fixes next-20190917 for me regarding SCSI generic.

 block/scsi_ioctl.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index cbeb629ee917..650bade5ea5a 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -607,14 +607,14 @@ int put_sg_io_hdr(const struct sg_io_hdr *hdr, void __user *argp)
 			.info		 = hdr->info,
 		};
 
-		if (copy_to_user(argp, &hdr32, sizeof(hdr)))
+		if (copy_to_user(argp, &hdr32, sizeof(hdr32)))
 			return -EFAULT;
 
 		return 0;
 	}
 #endif
 
-	if (copy_to_user(argp, &hdr, sizeof(hdr)))
+	if (copy_to_user(argp, hdr, sizeof(*hdr)))
 		return -EFAULT;
 
 	return 0;
@@ -659,7 +659,7 @@ int get_sg_io_hdr(struct sg_io_hdr *hdr, const void __user *argp)
 	}
 #endif
 
-	if (copy_from_user(&hdr, argp, sizeof(hdr)))
+	if (copy_from_user(hdr, argp, sizeof(*hdr)))
 		return -EFAULT;
 
 	return 0;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] compat_ioctl: fix reimplemented SG_IO handling causing -EINVAL from sg_io()
  2019-09-18 15:34 [PATCH] compat_ioctl: fix reimplemented SG_IO handling causing -EINVAL from sg_io() Steffen Maier
@ 2019-10-09 16:01 ` Arnd Bergmann
  0 siblings, 0 replies; 2+ messages in thread
From: Arnd Bergmann @ 2019-10-09 16:01 UTC (permalink / raw)
  To: Steffen Maier
  Cc: James E . J . Bottomley, Martin K . Petersen, Doug Gilbert,
	linux-scsi, linux-s390, Benjamin Block, Heiko Carstens,
	Vasily Gorbik, linux-kernel, Jens Axboe, Al Viro,
	Linux FS-devel Mailing List, Chaitanya Kulkarni, Thomas Gleixner,
	Mauro Carvalho Chehab, Omar Sandoval, linux-block,
	Linux-Next Mailing List, Mark Brown, dm-devel

On Wed, Sep 18, 2019 at 5:35 PM Steffen Maier <maier@linux.ibm.com> wrote:
>
> scsi_cmd_ioctl() had hdr as on stack auto variable and called
> copy_{from,to}_user with the address operator &hdr and sizeof(hdr).
>
> After the refactoring, {get,put}_sg_io_hdr() takes a pointer &hdr.
> So the copy_{from,to}_user within the new helper functions should
> just take the given pointer argument hdr and sizeof(*hdr).
>
> I saw -EINVAL from sg_io() done by /usr/lib/udev/scsi_id which could
> in turn no longer whitelist SCSI disks for devicemapper multipath.
>
> Signed-off-by: Steffen Maier <maier@linux.ibm.com>
> Fixes: 4f45155c29fd ("compat_ioctl: reimplement SG_IO handling")
> ---
>
> Arnd, I'm not sure about the sizeof(hdr32) change in the compat part in
> put_sg_io_hdr().
>
> This is for next, probably via Arnd's y2038/y2038,
> and it fixes next-20190917 for me regarding SCSI generic.

Hi Steffen,

Sorry for the long delay. I ended up not sending my pull request for
v5.4, so the bug is not there. I have now rebased my branch
on top of v5.4-rc2 and plan to send it for the v5.5 merge window.

I have folded your bugfix into my original patch, hope that's ok with
you. Tomorrow's linux-next should be fixed.

    Arnd

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2019-09-18 15:34 [PATCH] compat_ioctl: fix reimplemented SG_IO handling causing -EINVAL from sg_io() Steffen Maier
2019-10-09 16:01 ` Arnd Bergmann

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