Patch "libata: reject passthrough WRITE SAME requests" has been added to the 4.11-stable tree

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

libata: reject passthrough WRITE SAME requests

to the 4.11-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-4.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Christoph Hellwig <[email protected]>
Date: Tue, 25 Apr 2017 13:39:54 +0200
Subject: libata: reject passthrough WRITE SAME requests

From: Christoph Hellwig <[email protected]>

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.

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

@@ -3462,6 +3462,14 @@ 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 [email protected] are

queue-4.11/fs-block_dev-always-invalidate-cleancache-in-invalidate_bdev.patch queue-4.11/target-fileio-fix-zero-length-read-and-write-handling.patch queue-4.11/libata-reject-passthrough-write-same-requests.patch queue-4.11/dm-rq-check-blk_mq_register_dev-return-value-in-dm_mq_init_request_queue.patch queue-4.11/fs-fix-data-invalidation-in-the-cleancache-during-direct-io.patch