From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754949AbbGASu4 (ORCPT ); Wed, 1 Jul 2015 14:50:56 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44961 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753661AbbGASkz (ORCPT ); Wed, 1 Jul 2015 14:40:55 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marek Szyprowski , Will Deacon Subject: [PATCH 3.14 01/34] arm64: dma-mapping: always clear allocated buffers Date: Wed, 1 Jul 2015 11:40:08 -0700 Message-Id: <20150701183955.364087102@linuxfoundation.org> X-Mailer: git-send-email 2.4.4 In-Reply-To: <20150701183955.306219425@linuxfoundation.org> References: <20150701183955.306219425@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marek Szyprowski commit 6829e274a623187c24f7cfc0e3d35f25d087fcc5 upstream. Buffers allocated by dma_alloc_coherent() are always zeroed on Alpha, ARM (32bit), MIPS, PowerPC, x86/x86_64 and probably other architectures. It turned out that some drivers rely on this 'feature'. Allocated buffer might be also exposed to userspace with dma_mmap() call, so clearing it is desired from security point of view to avoid exposing random memory to userspace. This patch unifies dma_alloc_coherent() behavior on ARM64 architecture with other implementations by unconditionally zeroing allocated buffer. Signed-off-by: Marek Szyprowski [will: ported to 3.14.y] Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/mm/dma-mapping.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -54,8 +54,7 @@ static void *arm64_swiotlb_alloc_coheren *dma_handle = phys_to_dma(dev, page_to_phys(page)); addr = page_address(page); - if (flags & __GFP_ZERO) - memset(addr, 0, size); + memset(addr, 0, size); return addr; } else { return swiotlb_alloc_coherent(dev, size, dma_handle, flags);