This is a note to let you know that I've just added the patch titled
brd: fix overflow in __brd_direct_access
to the 4.13-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:
brd-fix-overflow-in-__brd_direct_access.patch
and it can be found in the queue-4.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 02a4843618fb35f847cf8c31cd3893873aa0edde Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Date: Wed, 13 Sep 2017 09:17:57 -0400
Subject: brd: fix overflow in __brd_direct_access
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
commit 02a4843618fb35f847cf8c31cd3893873aa0edde upstream.
The code in __brd_direct_access multiplies the pgoff variable by page size
and divides it by 512. It can cause overflow on 32-bit architectures. The
overflow happens if we create ramdisk larger than 4G and use it as a
sparse device.
This patch replaces multiplication and division with multiplication by the
number of sectors per page.
Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Fixes: 1647b9b959c7 ("brd: add dax_operations support")
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/block/brd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -339,7 +339,7 @@ static long __brd_direct_access(struct b
if (!brd)
return -ENODEV;
- page = brd_insert_page(brd, PFN_PHYS(pgoff) / 512);
+ page = brd_insert_page(brd, (sector_t)pgoff << PAGE_SECTORS_SHIFT);
if (!page)
return -ENOSPC;
*kaddr = page_address(page);
Patches currently in stable-queue which might be from mpatocka@xxxxxxxxxx are
queue-4.13/brd-fix-overflow-in-__brd_direct_access.patch
queue-4.13/dax-remove-the-pmem_dax_ops-flush-abstraction.patch
queue-4.13/dm-integrity-do-not-check-integrity-for-failed-read-operations.patch