Patch "libata: reject passthrough WRITE SAME requests" has been added to the 4.9-stable tree

Patch "libata: reject passthrough WRITE SAME requests" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    libata: reject passthrough WRITE SAME requests

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     libata-reject-passthrough-write-same-requests.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From c6ade20f5e50e188d20b711a618b20dd1d50457e Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Tue, 25 Apr 2017 13:39:54 +0200
Subject: libata: reject passthrough WRITE SAME requests

From: Christoph Hellwig <hch@lst.de>

commit c6ade20f5e50e188d20b711a618b20dd1d50457e upstream.

The WRITE SAME to TRIM translation rewrites the DATA OUT buffer.  While
the SCSI code accomodates for this by passing a read-writable buffer
userspace applications don't cater for this behavior.  In fact it can
be used to rewrite e.g. a readonly file through mmap and should be
considered as a security fix.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/ata/libata-scsi.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3405,6 +3405,14 @@ static unsigned int ata_scsi_write_same_
 	if (unlikely(!dev->dma_mode))
 		goto invalid_opcode;
 
+	/*
+	 * We only allow sending this command through the block layer,
+	 * as it modifies the DATA OUT buffer, which would corrupt user
+	 * memory for SG_IO commands.
+	 */
+	if (unlikely(blk_rq_is_passthrough(scmd->request)))
+		goto invalid_opcode;
+
 	if (unlikely(scmd->cmd_len < 16)) {
 		fp = 15;
 		goto invalid_fld;


Patches currently in stable-queue which might be from hch@lst.de are

queue-4.9/fs-block_dev-always-invalidate-cleancache-in-invalidate_bdev.patch
queue-4.9/target-fileio-fix-zero-length-read-and-write-handling.patch
queue-4.9/libata-reject-passthrough-write-same-requests.patch
queue-4.9/dm-rq-check-blk_mq_register_dev-return-value-in-dm_mq_init_request_queue.patch

Re: Patch "libata: reject passthrough WRITE SAME requests" has been added to the 4.9-stable tree

[Greg KH]

On Thu, May 18, 2017 at 09:46:58AM +0200, gregkh@linuxfoundation.org wrote:
> 
> This is a note to let you know that I've just added the patch titled
> 
>     libata: reject passthrough WRITE SAME requests
> 
> to the 4.9-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>      libata-reject-passthrough-write-same-requests.patch
> and it can be found in the queue-4.9 subdirectory.

Also broke the build in 4.9, so I'm dropping it there as well.

thanks,

greg k-h