Patch "dm crypt: allow unaligned bv_offset" has been added to the 4.14-stable tree

Patch "dm crypt: allow unaligned bv_offset" has been added to the 4.14-stable tree

[gregkh]

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

    dm crypt: allow unaligned bv_offset

to the 4.14-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:
     dm-crypt-allow-unaligned-bv_offset.patch
and it can be found in the queue-4.14 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 0440d5c0ca9744b92a07aeb6df0a9a75db6f4280 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Tue, 7 Nov 2017 10:35:57 -0500
Subject: dm crypt: allow unaligned bv_offset
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Mikulas Patocka <mpatocka@redhat.com>

commit 0440d5c0ca9744b92a07aeb6df0a9a75db6f4280 upstream.

When slub_debug is enabled kmalloc returns unaligned memory. XFS uses
this unaligned memory for its buffers (if an unaligned buffer crosses a
page, XFS frees it and allocates a full page instead - see the function
xfs_buf_allocate_memory).

dm-crypt checks if bv_offset is aligned on page size and these checks
fail with slub_debug and XFS.

Fix this bug by removing the bv_offset checks. Switch to checking if
bv_len is aligned instead of bv_offset (this check should be sufficient
to prevent overruns if a bio with too small bv_len is received).

Fixes: 8f0009a22517 ("dm crypt: optionally support larger encryption sector size")
Reported-by: Bruno Prémont <bonbons@sysophe.eu>
Tested-by: Bruno Prémont <bonbons@sysophe.eu>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/md/dm-crypt.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1075,7 +1075,7 @@ static int crypt_convert_block_aead(stru
 	BUG_ON(cc->integrity_iv_size && cc->integrity_iv_size != cc->iv_size);
 
 	/* Reject unexpected unaligned bio. */
-	if (unlikely(bv_in.bv_offset & (cc->sector_size - 1)))
+	if (unlikely(bv_in.bv_len & (cc->sector_size - 1)))
 		return -EIO;
 
 	dmreq = dmreq_of_req(cc, req);
@@ -1168,7 +1168,7 @@ static int crypt_convert_block_skcipher(
 	int r = 0;
 
 	/* Reject unexpected unaligned bio. */
-	if (unlikely(bv_in.bv_offset & (cc->sector_size - 1)))
+	if (unlikely(bv_in.bv_len & (cc->sector_size - 1)))
 		return -EIO;
 
 	dmreq = dmreq_of_req(cc, req);


Patches currently in stable-queue which might be from mpatocka@redhat.com are

queue-4.14/dm-allocate-struct-mapped_device-with-kvzalloc.patch
queue-4.14/dm-integrity-allow-unaligned-bv_offset.patch
queue-4.14/dm-crypt-allow-unaligned-bv_offset.patch