From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:34482 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752348AbdJCMc2 (ORCPT ); Tue, 3 Oct 2017 08:32:28 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Williams , Mikulas Patocka , Jens Axboe Subject: [PATCH 4.13 064/110] brd: fix overflow in __brd_direct_access Date: Tue, 3 Oct 2017 14:29:26 +0200 Message-Id: <20171003114243.903995083@linuxfoundation.org> In-Reply-To: <20171003114241.408583531@linuxfoundation.org> References: <20171003114241.408583531@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mikulas Patocka 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 Signed-off-by: Mikulas Patocka Fixes: 1647b9b959c7 ("brd: add dax_operations support") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- 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);